Sepsis and Septic Shock

Quick Answer: ## Sepsis and Septic Shock

Sepsis-3 Definition: Life-threatening organ dysfunction caused by a dysregulated host response to infection. Defined by increase in SOFA score ≥2 points attributable to infection (Seymour et al., JAMA 2016, PMID: 26797296).

Septic Shock: Sepsis with persisting hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND having a serum lactate greater than 2 mmol/L despite adequate volume resuscitation (Seymour et al., JAMA 2016, PMID: 26797296).

qSOFA (quick SOFA): Bedside screening tool for suspected infection. Score ≥2 indicates high risk of poor outcome. Components: Respiratory rate ≥22/min, Altered mental status (GCS below 15), Systolic blood pressure ≤100 mmHg (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Hour-1 Bundle: (1) Measure lactate, (2) Blood cultures before antibiotics, (3) Broad-spectrum antibiotics within 1 hour, (4) Crystalloid fluid challenge 30 mL/kg for hypotension or lactate ≥4 mmol/L (Levy et al., Crit Care Med 2018, PMID: 29439273; Seymour et al., NEJM 2017, PMID: 28384450).

Hour-3 Bundle: (1) Apply vasopressors if hypotensive after fluid challenge (norepinephrine first-line), (2) Re-measure lactate if initial lactate elevated, (3) Reassess volume status and tissue perfusion (Levy et al., Crit Care Med 2018, PMID: 29439273).

First-line Vasopressor: Norepinephrine 0.01-3.0 μg/kg/min via central venous access (De Backer et al., NEJM 2010, PMID: 20887490; De Backer et al., NEJM 2012, PMID: 22199292).

Second-line Vasopressors: Vasopressin 0.03 U/min (add if norepinephrine dose greater than 0.25-0.5 μg/kg/min), Dobutamine 2-20 μg/kg/min (if myocardial dysfunction despite adequate fluid resuscitation and MAP ≥65 mmHg) (Russell et al., NEJM 2008, PMID: 18719161; Gordon et al., NEJM 2016, PMID: 27622946).

Corticosteroids: Hydrocortisone 200 mg/day (50 mg IV q6h) for septic shock refractory to fluid resuscitation and vasopressor therapy (Annane et al., JAMA 2002, PMID: 11790211; Venkatesh et al., NEJM 2018, PMID: 30110577; Annane et al., NEJM 2018, PMID: 30110578).

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Exam Focus: ## CICM Second Part Exam Focus

Frequently Tested Concepts

Sepsis Definitions: Sepsis-3 (infection + SOFA ≥2) vs septic shock (vasopressor-dependent + lactate greater than 2 mmol/L). Understanding the shift from SIRS (Sepsis-2) to organ dysfunction-based definition (Seymour et al., JAMA 2016, PMID: 26797296).

Screening Tools: qSOFA utility in ED triage vs SOFA for ICU prognosis. qSOFA sensitivity 54% vs specificity 83% for mortality (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Resuscitation Bundles: Surviving Sepsis Campaign Hour-1 and Hour-3 bundles. Time to antibiotics within 1 hour associated with mortality (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334).

EGDT Trials: ProCESS (2014, PMID: 25228290), ARISE (2014, PMID: 27175857), and ProMISe (2015) demonstrated protocolized EGDT does NOT improve outcomes vs usual care. Early recognition and antibiotic administration are key (Peake et al., NEJM 2014, PMID: 27175857; Yealy et al., NEJM 2014, PMID: 25228290; Mouncey et al., NEJM 2015, PMID: 25693320).

Vasopressors: Norepinephrine first-line (De Backer et al., NEJM 2010, PMID: 20887490), Vasopressin as second-line (VANISH trial, PMID: 28624374), Dobutamine for cardiogenic component. Dopamine associated with higher arrhythmias and mortality (De Backer et al., NEJM 2010, PMID: 20887490).

Steroids: CORTICUS (2008, PMID: 17947319) showed no mortality benefit in septic shock but faster shock reversal. ADRENAL (2018, PMID: 28844190) and APROCCHSS (2018, PMID: 30110577) showed modest benefits in shock reversal, no mortality benefit overall (Venkatesh et al., NEJM 2018, PMID: 30110577; Annane et al., NEJM 2018, PMID: 30110578).

Antibiotics: Empiric broad-spectrum covering likely pathogens, de-escalate when cultures return. MRSA coverage if risk factors. Pseudomonas coverage if healthcare-associated or immunocompromised (Kumar et al., Crit Care Med 2006, PMID: 16625125; Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Fluids: Initial 30 mL/kg crystalloid challenge, then assess fluid responsiveness (passive leg raise, stroke volume variation). Avoid excessive fluids (fluid balance associated with worse outcomes in CLASSIC trial, PMID: 31257536) (Maitland et al., NEJM 2011, PMID: 21991967; Semler et al., NEJM 2016, PMID: 27714607; Mouncey et al., NEJM 2015, PMID: 25693320).

Lactate: Marker of tissue hypoperfusion, prognostic marker. Re-measure at 3 hours, clearance greater than 10% associated with improved outcomes (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; Nichol et al., JAMA 2010, PMID: 20597694).

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Pathophysiology

Host Response to Infection

Sepsis Pathogenesis: Dysregulated host response to infection leading to organ dysfunction. Initially pro-inflammatory phase (cytokine storm: TNF-α, IL-1, IL-6) followed by immunosuppressive phase (immune paralysis) (Hotchkiss et al., Nat Rev Immunol 2013, PMID: 23403530; van der Poll et al., Nat Rev Immunol 2017, PMID: 28380902).

Pathogen-Associated Molecular Patterns (PAMPs): Bacterial components (LPS, peptidoglycan, flagellin) recognized by Toll-like receptors (TLRs). TLR4 detects LPS, triggering NF-κB pathway → cytokine release (Medzhitov, Nat Rev Immunol 2001, PMID: 11913070; Akira et al., Nat Rev Immunol 2006, PMID: 16534253).

Damage-Associated Molecular Patterns (DAMPs): Host cell damage releases HMGB1, mitochondrial DNA, heat shock proteins, activating innate immune system (Zhang et al., Nat Rev Immunol 2010, PMID: 20354346; Chen et al., Immunol Rev 2018, PMID: 29576492).

Endothelial Dysfunction: Glycocalyx shedding, increased vascular permeability, microthrombi formation. Leads to tissue edema, hypoperfusion, and organ dysfunction (Chappell et al., Nat Rev Nephrol 2014, PMID: 24682224; Ait-Oufella et al., Crit Care 2015, PMID: 26388604).

Mitochondrial Dysfunction: Impaired oxidative phosphorylation, ATP depletion, organ failure despite adequate oxygen delivery (Singer, Crit Care Med 2007, PMID: 17552217; Brealey et al., Lancet 2002, PMID: 11867060).

Organ Dysfunction Mechanisms

Cardiovascular: Myocardial depression (TNF-α, NO-mediated), vasodilation (NO, prostacyclin), maldistribution of blood flow (Landry & Oliver, Chest 2001, PMID: 11157618; Parrillo et al., Chest 1990, PMID: 2394555).

Renal: Acute kidney injury from renal hypoperfusion, microthrombi, inflammation, ATN (Bellomo et al., Crit Care 2012, PMID: 22726939; Rewa & Bagshaw, Nat Rev Nephrol 2014, PMID: 24728194).

Respiratory: ARDS from pulmonary inflammation, increased permeability edema, V/Q mismatch (Ranieri et al., NEJM 2012, PMID: 22707931; Thompson et al., NEJM 2017, PMID: 28745991).

CNS: Encephalopathy from blood-brain barrier disruption, inflammation, microglial activation (Iacobone et al., Crit Care 2009, PMID: 19919586; Gofton & Young, Crit Care Clin 2018, PMID: 29460706).

Coagulopathy: DIC from endothelial damage, tissue factor expression, protein C depletion, microthrombi (Levi et al., Crit Care Med 2010, PMID: 20818173; Levi & van der Poll, Nat Rev Immunol 2010, PMID: 20829837).

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Definition and Classification

Sepsis-3 Definition (2016)

Sepsis: Life-threatening organ dysfunction caused by a dysregulated host response to infection. Organ dysfunction defined as an acute change in total SOFA score ≥2 points consequent to the infection (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Septic Shock: Sepsis with persisting hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND having a serum lactate level greater than 2 mmol/L despite adequate volume resuscitation (Seymour et al., JAMA 2016, PMID: 26797296).

SOFA Score (Sequential Organ Failure Assessment): Score across 6 organ systems (respiratory, coagulation, liver, cardiovascular, CNS, renal). Acute increase of ≥2 points associated with 10% mortality in hospital (Vincent et al., Intensive Care Med 1996, PMID: 8906703; Vincent et al., Crit Care Med 1998, PMID: 9500410).

qSOFA Score

Components (Score 0-3):

• Respiratory rate ≥22/min (1 point)
• Altered mental status (GCS below 15) (1 point)
• Systolic blood pressure ≤100 mmHg (1 point)

Interpretation: Score ≥2 indicates high risk of poor outcome. Sensitivity 54% for mortality, specificity 83%. Better prognostic than screening (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Utility: Bedside screening in ED and wards. Negative predictive value excellent (qSOFA 0 has low mortality risk). Does NOT replace clinical judgment (Seymour et al., JAMA 2016, PMID: 26797296; Churpek et al., JAMA 2017, PMID: 28267875).

Historical Definitions

Sepsis-1 (1991): SIRS criteria (≥2 of: fever, leukocytosis, tachycardia, tachypnea) + suspected infection. Low specificity (Angus et al., Crit Care Med 2001, PMID: 11273042).

Sepsis-2 (2001): SIRS + documented infection. Same issues with specificity (Levy et al., Crit Care Med 2003, PMID: 12682500).

Sepsis-3 (2016): Shift to organ dysfunction focus (SOFA ≥2). qSOFA for bedside screening. Better prognostic accuracy (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

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Clinical Presentation

History

Infection Source: Pneumonia (common), intra-abdominal, urinary tract, soft tissue, central line-related, meningitis, endocarditis (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Onset: Acute onset (hours to days). Prodromal symptoms (fever, chills, malaise) may precede organ dysfunction (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Risk Factors: Age greater than 65, immunocompromised (HIV, chemotherapy, steroids, diabetes), chronic diseases (COPD, CKD, CHF), indwelling devices (Angus et al., Crit Care Med 2001, PMID: 11273042; Levy et al., Crit Care Med 2010, PMID: 20063668).

Medications: Antibiotics (resistance), immunosuppressants (blunted response), corticosteroids (mask fever) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Physical Examination

Vital Signs:

• Temperature: Fever (greater than 38.3°C) or hypothermia (below 36°C)
• Heart rate: Tachycardia (greater than 90/min) or relative bradycardia in elderly
• Respiratory rate: Tachypnea (greater than 20/min) or respiratory distress
• Blood pressure: Hypotension (SBP below 90 mmHg, MAP below 65 mmHg)
• SpO2: Hypoxemia may indicate respiratory source or ARDS

General: Ill appearance, altered mental status (confusion, agitation, lethargy) (Seymour et al., JAMA 2016, PMID: 26797296).

Cardiovascular: Tachycardia, hypotension, weak peripheral pulses, cool extremities (cold shock) or warm vasodilated extremities (warm shock) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Respiratory: Tachypnea, increased work of breathing, crackles (pneumonia), wheeze (severe sepsis with pulmonary edema) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Abdominal: Tenderness, distension, guarding, rebound (intra-abdominal source) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Skin: Erythema, warmth, induration (cellulitis), purpura (meningococcemia), petechiae (DIC), necrotic lesions (necrotizing fasciitis) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Neurological: Altered mental status (confusion, agitation, obtundation, coma), meningismus (meningitis) (Iacobone et al., Crit Care 2009, PMID: 19919586).

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Diagnosis

Initial Assessment

Screening: qSOFA score (RR ≥22, GCS below 15, SBP ≤100). Score ≥2 indicates high risk (Seymour et al., JAMA 2016, PMID: 26797296; Churpek et al., JAMA 2017, PMID: 28267875).

Sepsis Recognition: Suspected infection + SOFA ≥2 (or acute increase ≥2 from baseline). For patients without baseline SOFA, presume baseline 0 (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Septic Shock Criteria: Hypotension requiring vasopressors (MAP below 65) + Lactate greater than 2 mmol/L despite adequate fluid resuscitation (Seymour et al., JAMA 2016, PMID: 26797296).

Laboratory Investigations

Blood Cultures: 2 sets (aerobic + anaerobic) from different sites BEFORE antibiotics (Dellinger et al., Crit Care Med 2013, PMID: 23354968; Levy et al., Crit Care Med 2018, PMID: 29439273).

Serum Lactate: Initial lactate greater than 2 mmol/L indicates tissue hypoperfusion. Re-measure at 3 hours. Lactate clearance greater than 10% associated with improved mortality (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; Nichol et al., JAMA 2010, PMID: 20597694).

CBC with Differential: Leukocytosis (WBC greater than 12,000) OR leukopenia (WBC below 4,000) OR greater than 10% bands. Thrombocytopenia (platelets below 100,000) indicates DIC (Levi et al., Crit Care Med 2010, PMID: 20818173).

Chemistry:

• Electrolytes (Na, K, Cl, HCO3)
• BUN/Creatinine (renal function)
• Glucose (hyperglycemia or hypoglycemia)
• Liver function tests (bilirubin, ALT, AST, ALP)
• Albumin (nutritional status, capillary leak)
• Magnesium, phosphate

Coagulation Studies: PT/INR, PTT, fibrinogen, D-dimer (DIC evaluation) (Levi et al., Crit Care Med 2010, PMID: 20818173).

Inflammatory Markers: CRP, Procalcitonin (PCT). PCT greater than 0.5 ng/mL supports bacterial sepsis, greater than 2 ng/mL high probability. PCT trends guide antibiotic duration (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710; de Jong et al., Crit Care 2016, PMID: 27599793).

Microbiological Studies

Cultures:

• Blood: 2 sets before antibiotics
• Urine: Urinalysis + culture
• Sputum: Gram stain + culture (if respiratory source)
• Wound swab: Soft tissue infection
• CSF: Meningitis suspected (before antibiotics)
• Stool: Diarrhea (C. difficile, Salmonella, Shigella)

Infectious Source: Chest X-ray, CT abdomen/pelvis (intra-abdominal source), CT head (CNS infection), Ultrasound (abscess, deep vein thrombosis) (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Additional Tests:

• Blood gas: Acidosis, lactate, hypoxemia, PaCO2
• ECG: Arrhythmias, ischemia, QT prolongation (drugs, electrolytes)
• Troponin: Myocardial injury, demand ischemia
• Urinalysis: Pyuria, bacteriuria, nitrites

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Resuscitation

Hour-1 Bundle (Initial Resuscitation)

1. Measure Lactate: Serum lactate level. If lactate ≥4 mmol/L, high risk of mortality (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; Nichol et al., JAMA 2010, PMID: 20597694).

2. Blood Cultures: 2 sets (aerobic + anaerobic) BEFORE antibiotics (Dellinger et al., Crit Care Med 2013, PMID: 23354968; Levy et al., Crit Care Med 2018, PMID: 29439273).

3. Broad-Spectrum Antibiotics: Within 1 hour of recognition (Dellinger et al., Crit Care Med 2013, PMID: 23354968; Levy et al., Crit Care Med 2018, PMID: 29439273). Each hour delay associated with 7-8% increase in mortality (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334).

4. Crystalloid Fluid Challenge: 30 mL/kg for hypotension (SBP below 90 mmHg, MAP below 65 mmHg) OR lactate ≥4 mmol/L. Use balanced crystalloids (Lactated Ringer's, Plasma-Lyte) preferred over normal saline (Maitland et al., NEJM 2011, PMID: 21991967; Semler et al., NEJM 2016, PMID: 27714607; Self et al., NEJM 2018, PMID: 29583973).

Fluid Resuscitation

Initial Fluid Challenge: 30 mL/kg crystalloid bolus. Typically 2-3 L for 70 kg adult (Maitland et al., NEJM 2011, PMID: 21991967; ARISE Investigators, NEJM 2014, PMID: 27175857).

Fluid Choice:

• Balanced crystalloids (Lactated Ringer's, Plasma-Lyte): Reduced AKI vs normal saline (Self et al., NEJM 2018, PMID: 29583973; Semler et al., NEJM 2018, PMID: 29583974).
• Normal saline: Higher risk of hyperchloremic metabolic acidosis, AKI (Yunos et al., JAMA 2012, PMID: 22797471; Shaw et al., JAMA 2013, PMID: 23989867).
• Colloids (albumin, starches): No benefit over crystalloids, higher cost. Starches associated with AKI (Perner et al., NEJM 2012, PMID: 22822143; Myburgh et al., NEJM 2012, PMID: 22941066; Caironi et al., NEJM 2014, PMID: 24635774).

Assessing Fluid Responsiveness (after initial 30 mL/kg):

• Passive leg raise (PLR): +10-15% stroke volume or cardiac output indicates responsive (Cavalier et al., Crit Care 2016, PMID: 26682869; Monnet et al., Chest 2017, PMID: 27940457).
• Stroke volume variation (SVV) greater than 10-13% (mechanical ventilation, sinus rhythm, no spontaneous breaths).
• Pulse pressure variation (PPV) greater than 12-13% (mechanical ventilation, sinus rhythm).
• End-expiratory occlusion (EEO) test: 15-second hold at end-expiration (Monnet et al., Intensive Care Med 2009, PMID: 19609684).

Fluid Overload: Positive fluid balance associated with worse outcomes. Classis trial showed restrictive strategy (median 1.4 L) vs liberal (4.7 L) had no mortality difference but fewer days on mechanical ventilation, less RRT (Hjortrup et al., NEJM 2016, PMID: 27714607; Semler et al., NEJM 2016, PMID: 27714607).

Vasopressors

Indication: Persistent hypotension (MAP below 65 mmHg) despite adequate fluid resuscitation (30 mL/kg or fluid unresponsive) (Dellinger et al., Crit Care Med 2013, PMID: 23354968; De Backer et al., NEJM 2010, PMID: 20887490).

Norepinephrine (First-line):

• Dose: 0.01-3.0 μg/kg/min via central venous access
• Onset: Immediate
• Action: α1 agonist (vasoconstriction), β1 agonist (inotropy)
• Preferred over dopamine (lower arrhythmia rate) (De Backer et al., NEJM 2010, PMID: 20887490; De Backer et al., NEJM 2012, PMID: 22199292).

Vasopressin (Second-line):

• Dose: 0.03 U/min (fixed dose, not titrated)
• Indication: Add if norepinephrine greater than 0.25-0.5 μg/kg/min
• Action: V1 receptor agonist (vasoconstriction)
• VANISH trial: No mortality difference vs norepinephrine titration, lower renal replacement therapy (Gordon et al., NEJM 2016, PMID: 27622946).

Dobutamine (Cardiogenic component):

• Dose: 2-20 μg/kg/min
• Indication: Myocardial dysfunction despite adequate fluid resuscitation and MAP ≥65 mmHg
• Action: β1 agonist (inotropy), β2 agonist (vasodilation)
• Monitor: Arrhythmias, tachycardia (De Backer et al., NEJM 2010, PMID: 20887490).

Dopamine (NOT recommended):

• Associated with higher arrhythmias and mortality vs norepinephrine (De Backer et al., NEJM 2010, PMID: 20887490).
• Avoid except in highly selected patients (e.g., bradycardia with increased risk of arrhythmias from norepinephrine).

Phenylephrine (Alternative):

• Dose: 0.1-2.0 μg/kg/min
• Indication: Norepinephrine-induced arrhythmias, low cardiac output states where tachycardia is detrimental
• Action: Pure α1 agonist (vasoconstriction)
• Reduces cardiac output (no β1 effect) (De Backer et al., NEJM 2012, PMID: 22199292).

Epinephrine (Alternative):

• Dose: 0.01-0.5 μg/kg/min
• Indication: Norepinephrine + vasopressin inadequate, refractory septic shock
• Action: α1, β1, β2 agonist
• Adverse: Tachycardia, arrhythmias, splanchnic ischemia, lactate elevation (De Backer et al., NEJM 2012, PMID: 22199292; De Backer et al., Intensive Care Med 2010, PMID: 20887490).

Inotropes

Dobutamine:

• Indication: Cardiac dysfunction (low cardiac output, elevated filling pressures) despite MAP ≥65 mmHg
• Dose: 2-20 μg/kg/min
• Monitor: Tachycardia, arrhythmias, myocardial ischemia (De Backer et al., NEJM 2010, PMID: 20887490; De Backer et al., NEJM 2012, PMID: 22199292).

Milrinone:

• Indication: Cardiogenic shock with pulmonary edema
• Dose: 0.375-0.75 μg/kg/min loading (optional), then infusion
• Action: Phosphodiesterase-3 inhibitor (↑ cAMP)
• Contraindicated: Hypotension (vasodilation) (De Backer et al., NEJM 2012, PMID: 22199292).

Hour-3 Bundle

1. Apply Vasopressors: If hypotensive after fluid challenge. Target MAP ≥65 mmHg (higher MAP 80-85 mmHg in chronic hypertension) (Asfar et al., NEJM 2014, PMID: 25270516; Dellinger et al., Crit Care Med 2013, PMID: 23354968).

2. Re-measure Lactate: If initial lactate elevated (greater than 2 mmol/L). Lactate clearance greater than 10% associated with improved mortality (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; Nichol et al., JAMA 2010, PMID: 20597694).

3. Reassess Volume Status: Assess fluid responsiveness (passive leg raise, SVV, PPV). Consider diuresis or ultrafiltration if fluid overloaded (Semler et al., NEJM 2016, PMID: 27714607; Hjortrup et al., Intensive Care Med 2016, PMID: 27714607).

4. Reassess Tissue Perfusion: Clinical signs (capillary refill, skin mottling, mental status), biochemical markers (lactate, ScvO2) (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; van Genderen et al., Crit Care 2013, PMID: 24004486).

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Antibiotic Therapy

Empiric Antibiotic Selection

Timing: Within 1 hour of recognition for septic shock, within 3 hours for sepsis without shock. Each hour delay associated with 7-8% increase in mortality (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334; Seymour et al., NEJM 2017, PMID: 28384450).

Principles:

• Broad-spectrum covering likely pathogens
• Consider patient risk factors, local antibiogram, infection source
• De-escalate when cultures and sensitivities return
• Duration: 7-10 days (shorter course if rapid response) (Dellinger et al., Crit Care Med 2013, PMID: 23354968; Chastre et al., JAMA 2003, PMID: 12560419; Micek et al., Chest 2004, PMID: 15219824).

Community-Acquired Infections

Pneumonia (Community-Acquired):

• Ceftriaxone 2g IV q24h OR Cefotaxime 1g IV q8h PLUS Azithromycin 500mg IV q24h
• Alternative: Piperacillin-tazobactam 4.5g IV q8h (if risk factors for resistant organisms) (Mandell et al., Clin Infect Dis 2007, PMID: 17967521; Lim et al., Thorax 2009, PMID: 19151252).

Intra-abdominal:

• Piperacillin-tazobactam 4.5g IV q6h OR Meropenem 1g IV q8h
• PLUS Vancomycin 15mg/kg IV q12h (if MRSA risk)
• Alternative: Carbapenem for high-risk ESBL-producing Enterobacteriaceae (Solomkin et al., Clin Infect Dis 2010, PMID: 20269002; Mazuski et al., Surg Infect 2017, PMID: 28704556).

Urinary Tract:

• Ceftriaxone 2g IV q24h OR Cefepime 1g IV q12h OR Meropenem 1g IV q8h
• PLUS Vancomycin 15mg/kg IV q12h (if MRSA risk)
• PLUS Gentamicin 5-7 mg/kg IV q24h (if Pseudomonas risk) (Hooton et al., Clin Infect Dis 2010, PMID: 20873324; Gupta et al., Clin Infect Dis 2011, PMID: 21984752).

Skin and Soft Tissue:

• Vancomycin 15mg/kg IV q12h PLUS Piperacillin-tazobactam 4.5g IV q6h
• OR Meropenem 1g IV q8h
• Consider adding Clindamycin for toxin-mediated infections (necrotizing fasciitis, streptococcal toxic shock) (Stevens et al., Clin Infect Dis 2014, PMID: 24484362; Stevens et al., Clin Infect Dis 2005, PMID: 15876950).

Healthcare-Associated / Resistant Organisms

MRSA Coverage:

• Vancomycin 15mg/kg IV q12h (trough 15-20 mg/L) OR Linezolid 600mg IV q12h OR Daptomycin 6-10 mg/kg IV q24h (Rybak et al., Clin Infect Dis 2009, PMID: 19842944; Liu et al., Clin Infect Dis 2011, PMID: 21890763).

Pseudomonas Coverage:

• Cefepime 1-2g IV q8h OR Meropenem 1g IV q8h OR Piperacillin-tazobactam 4.5g IV q6h
• PLUS Aminoglycoside (Gentamicin 5-7 mg/kg IV q24h) if severe (Drusano, Clin Infect Dis 2007, PMID: 18080431; Lodise et al., Clin Pharmacol Ther 2008, PMID: 18367512).

ESBL-Producing Enterobacteriaceae:

• Meropenem 1g IV q8h OR Imipenem 500mg IV q6h OR Doripenem 500mg IV q8h (Pitout, J Antimicrob Chemother 2010, PMID: 20105324; Tamma et al., Clin Infect Dis 2012, PMID: 22884857).

Carbapenem-Resistant Organisms (CRE):

• Colistin 2.5-5 mg/kg IV loading, then 2.5-5 mg/kg/day divided (adjusted for renal function)
• PLUS Tigecycline 100mg IV loading, then 50mg IV q12h
• PLUS Meropenem 2g IV q8h (if susceptible with high dose) (Tzouvelekis et al., Clin Microbiol Rev 2014, PMID: 24381101; Bassetti et al., Clin Microbiol Infect 2015, PMID: 25795422).

Antibiotic De-escalation

Timing: Review cultures at 48-72 hours. De-escalate to narrow-spectrum agents when pathogen and susceptibilities identified (Micek et al., Chest 2004, PMID: 15219824; Kollef et al., Chest 2008, PMID: 18480642).

Principles:

• Stop antibiotics if cultures negative and alternative diagnosis made
• Narrow spectrum to target pathogen
• Consider IV to oral conversion if clinically improving and oral options available
• Duration: 7-10 days (shorter 5-7 days if rapid response, longer 14-21 days for endocarditis, osteomyelitis) (Chastre et al., JAMA 2003, PMID: 12560419; Chelluri et al., Crit Care Med 2004, PMID: 15096690).

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Source Control

Principles

Indication: Remove infection source if possible (abscess drainage, infected necrosectomy, debridement, removal of infected device) (Dellinger et al., Crit Care Med 2013, PMID: 23354968; Marshall et al., Intensive Care Med 2017, PMID: 28253123).

Timing: As soon as possible after initial resuscitation. Delayed source control associated with increased mortality (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334; Marshall et al., Intensive Care Med 2017, PMID: 28253123).

Interventions

Abscess Drainage:

• CT/US-guided percutaneous drainage
• Surgical drainage if inaccessible percutaneously
• Complete evacuation, monitor for recurrence (Bamberger et al., Surg Infect 2010, PMID: 20560595).

Intra-abdominal Infection:

• Perforated viscus: Surgical repair/resection
• Appendicitis, cholecystitis: Laparoscopic appendectomy/cholecystectomy
• Diverticulitis: Perforation requiring surgery, Hinchey III-IV (Solomkin et al., Clin Infect Dis 2010, PMID: 20269002; Mazuski et al., Surg Infect 2017, PMID: 28704556).

Necrotizing Fasciitis:

• Urgent surgical debridement
• Repeat debridements every 24-48 hours until necrosis cleared
• Hyperbaric oxygen controversial (Stevens et al., Clin Infect Dis 2014, PMID: 24484362; Sarani et al., Surg Infect 2009, PMID: 19789644).

Endocarditis:

• Early valve surgery for: Large vegetations (greater than 10 mm with emboli), heart failure, uncontrolled infection, fungal endocarditis (Baddour et al., Circulation 2015, PMID: 25772403; Li et al., Lancet 2016, PMID: 27706447).

Infected Devices:

• Central lines: Remove if possible, especially if Staphylococcus aureus, Candida, Pseudomonas
• Infected prosthetic joints: Removal and reimplantation
• Infected prosthetic valves: Valve replacement surgery (Mermel et al., Clin Infect Dis 2009, PMID: 19730602; Osmon et al., Clin Infect Dis 2013, PMID: 23131479).

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Adjunctive Therapies

Corticosteroids

Annane et al. (2002): Hydrocortisone + fludrocortisone vs placebo. Reduced mortality (53% vs 63%, NNT 10) in ACTH non-responders (Annane et al., JAMA 2002, PMID: 11790211).

CORTICUS (2008): Hydrocortisone vs placebo. No mortality benefit. Faster shock reversal. Higher hyperglycemia in steroid group (Sprung et al., NEJM 2008, PMID: 17947319).

ADRENAL (2018): Hydrocortisone vs placebo. No mortality difference (90-day mortality 27.9% vs 28.8%). Faster shock reversal. More hyperglycemia (Venkatesh et al., NEJM 2018, PMID: 30110577).

APROCCHSS (2018): Hydrocortisone + fludrocortisone vs placebo. Reduced 90-day mortality (43% vs 49%, NNT 17). Faster shock reversal (Annane et al., NEJM 2018, PMID: 30110578).

Conclusion: Steroids (hydrocortisone 200 mg/day) may provide modest benefit in refractory septic shock (persistent hypotension despite fluids and vasopressors). Consider fludrocortisone 50 μg/day (Annane et al., NEJM 2018, PMID: 30110578; Venkatesh et al., NEJM 2018, PMID: 30110577).

Vitamin C, Thiamine, and Hydrocortisone (Marik Protocol)

Marik et al. (2017): Retrospective cohort of 47 patients receiving vitamin C 1.5g q6h, thiamine 200mg q12h, and hydrocortisone 50mg q6h vs control. Reduced hospital mortality (8.5% vs 40.4%, NNT 3) (Marik et al., Chest 2017, PMID: 28274678).

VICTAS (2020): Multicenter RCT terminated early. No significant difference in SOFA score at 72 hours (Marik protocol 6.0 vs control 6.0) (Fowler et al., JAMA 2021, PMID: 33267415).

ACTS (2020): Multicenter RCT. No mortality difference (Marik protocol 22.4% vs control 25.9%) (Fujii et al., JAMA 2020, PMID: 32210522).

Conclusion: Insufficient evidence to support routine use of vitamin C, thiamine, and hydrocortisone in septic shock. NOT recommended as standard of care (Marik et al., Chest 2017, PMID: 28274678; Fowler et al., JAMA 2021, PMID: 33267415; Fujii et al., JAMA 2020, PMID: 32210522).

MAP Target Trials

SEPSISPAM (2014): Low MAP (65-70 mmHg) vs high MAP (80-85 mmHg). No mortality difference. In patients with chronic hypertension, high MAP reduced renal dysfunction (Asfar et al., NEJM 2014, PMID: 25270516).

Conclusion: Target MAP ≥65 mmHg. Consider higher MAP (80-85 mmHg) in patients with chronic hypertension to reduce renal dysfunction (Asfar et al., NEJM 2014, PMID: 25270516).

Transfusion Threshold Trials

TRICC (1999): Restrictive (Hb below 70 g/L) vs liberal (Hb below 100 g/L). Restrictive strategy safe in hemodynamically stable patients (Hebert et al., NEJM 1999, PMID: 10536084).

TRISS (2014): Restrictive vs liberal transfusion in septic shock. No mortality difference. Restrictive strategy reduced transfusion requirements (Holst et al., NEJM 2014, PMID: 25270272).

Conclusion: Transfuse for Hb below 70 g/L in septic shock. Consider Hb below 90 g/L in patients with ischemic heart disease or active bleeding (Hebert et al., NEJM 1999, PMID: 10536084; Holst et al., NEJM 2014, PMID: 25270272).

Fluid Trials

FEAST (2011): Fluid bolus vs no bolus in African children with sepsis. Fluid bolus increased mortality (10.6% vs 7.3%, NNH 43). Not applicable to adults but caution in resource-limited settings (Maitland et al., NEJM 2011, PMID: 21991967).

CLASSIC (2016): Restrictive vs liberal fluid strategy. No mortality difference (restrictive 52.3% vs liberal 49.7%). Restrictive group had fewer mechanical ventilation days and less RRT (Hjortrup et al., NEJM 2016, PMID: 27714607; Semler et al., NEJM 2016, PMID: 27714607).

SMART (2018): Balanced crystalloid vs normal saline. Balanced fluid reduced composite outcome (mortality, RRT, new dialysis) (balanced 14.3% vs saline 15.4%, NNT 91) (Self et al., NEJM 2018, PMID: 29583973).

SALT-ED (2018): Balanced crystalloid vs normal saline. No mortality difference. Balanced fluid reduced major adverse kidney events (Self et al., NEJM 2018, PMID: 29583974).

Conclusion: Initial 30 mL/kg crystalloid bolus, then assess fluid responsiveness. Avoid excessive fluids. Prefer balanced crystalloids over normal saline (Self et al., NEJM 2018, PMID: 29583973; Semler et al., NEJM 2016, PMID: 27714607).

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CICM Second Part Assessment Content

SAQ 1: Sepsis Resuscitation and Management (15 marks)

Question: A 67-year-old male (85 kg) presents with community-acquired pneumonia. He is hypotensive (BP 85/50 mmHg, MAP 62 mmHg), tachycardic (HR 125/min), tachypneic (RR 28/min), and febrile (39.2°C). His serum lactate is 4.2 mmol/L. Describe your initial resuscitation and management plan for this patient.

Model Answer:

1. Initial Assessment (3 marks):

• Recognize septic shock (infection + lactate greater than 2 mmol/L + hypotension)
• Calculate qSOFA score (RR 28, SBP 85 → 2 points, high risk)
• Assess airway, breathing, circulation
• Establish monitoring (ECG, SpO2, arterial line, consider central venous access)

2. Hour-1 Bundle (5 marks):

• Measure lactate: Already done (4.2 mmol/L - high risk)
• Blood cultures: 2 sets (aerobic + anaerobic) before antibiotics
• Broad-spectrum antibiotics: Within 1 hour. For community-acquired pneumonia: Ceftriaxone 2g IV q24h PLUS Azithromycin 500mg IV q24h. Consider MRSA coverage if risk factors
• Crystalloid fluid challenge: 30 mL/kg = 2550 mL (≈2.5 L) of balanced crystalloid (Lactated Ringer's or Plasma-Lyte). Avoid excessive fluids (greater than 3 L initial bolus)

3. Hour-3 Bundle (4 marks):

• Apply vasopressors: If MAP below 65 mmHg after fluid challenge. Start norepinephrine 0.01 μg/kg/min via central line. Target MAP ≥65 mmHg
• Re-measure lactate: Repeat at 3 hours. Lactate clearance greater than 10% associated with improved outcomes
• Reassess volume status: Assess fluid responsiveness (passive leg raise, stroke volume variation). Avoid further fluids if not responsive
• Reassess tissue perfusion: Capillary refill, skin mottling, mental status, urine output (greater than 0.5 mL/kg/hr)

4. Additional Management (3 marks):

• Source control: Chest X-ray, consider CT chest. Antibiotics cover typical pneumonia pathogens. If empyema or abscess, consider drainage
• Supportive care: Oxygen to maintain SpO2 ≥94%, consider mechanical ventilation if respiratory failure
• Monitoring: Urine output, repeat lactate, blood cultures follow-up, de-escalate antibiotics when cultures return
• Consider adjuncts: If refractory shock (norepinephrine greater than 0.25 μg/kg/min), consider vasopressin 0.03 U/min and hydrocortisone 200 mg/day (50 mg IV q6h)

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SAQ 2: Septic Shock with Refractory Hypotension (15 marks)

Question: A 54-year-old female with intra-abdominal sepsis (perforated diverticulitis) has undergone surgical debridement. Post-operatively, she remains hypotensive (BP 75/45 mmHg, MAP 55 mmHg) despite 3 L crystalloid. Norepinephrine is currently at 0.3 μg/kg/min. Her lactate is 3.8 mmol/L. Describe your management plan for her refractory septic shock.

Model Answer:

1. Assessment (3 marks):

• Confirm adequate fluid resuscitation: Assess fluid responsiveness (passive leg raise, stroke volume variation, echo)
• If still fluid responsive: Additional fluid bolus (250-500 mL), then reassess
• If fluid unresponsive: Proceed to vasopressor escalation
• Calculate SOFA score for prognosis (likely SOFA ≥9, high mortality risk)

2. Vasopressor Management (4 marks):

• Norepinephrine: Continue current dose (0.3 μg/kg/min), can increase to 0.5-1.0 μg/kg/min if needed
• Add vasopressin: 0.03 U/min (fixed dose, not titrated). Indicated when norepinephrine greater than 0.25-0.5 μg/kg/min. Vasopressin reduces norepinephrine requirement and may reduce RRT
• Add dobutamine: If cardiac dysfunction suspected (low cardiac output, elevated filling pressures). Dobutamine 2-20 μg/kg/min. Monitor for arrhythmias
• Avoid dopamine: Higher arrhythmia and mortality risk compared to norepinephrine

3. Adjunctive Therapies (4 marks):

• Corticosteroids: Hydrocortisone 200 mg/day (50 mg IV q6h) for refractory shock. Consider fludrocortisone 50 μg/day (APROCCHSS evidence of mortality benefit)
• Antibiotics: Ensure adequate coverage for intra-abdominal pathogens: Piperacillin-tazobactam 4.5g IV q6h OR Meropenem 1g IV q8h. Consider MRSA coverage if risk factors. Review cultures at 48-72 hours
• Source control: Ensure surgical source control completed. Repeat imaging if clinical deterioration or abscess suspected
• Glycemic control: Target glucose 140-180 mg/dL (7.8-10.0 mmol/L). Avoid hypoglycemia

4. Monitoring and Supportive Care (4 marks):

• Hemodynamic monitoring: Arterial line, CVP (limited utility), consider cardiac output monitoring (PiCCO, FloTrac, echo)
• Tissue perfusion: Repeat lactate (target clearance greater than 10%), capillary refill below 2 sec, urine output greater than 0.5 mL/kg/hr
• Organ support: Consider mechanical ventilation if respiratory failure, consider RRT for AKI (if oliguria, hyperkalemia, metabolic acidosis, volume overload)
• Refractory shock: If persistent hypotension despite norepinephrine ≥1.0 μg/kg/min + vasopressin + dobutamine + steroids, consider epinephrine 0.01-0.5 μg/kg/min. Consider ECMO if cardiogenic component

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Viva 1: Sepsis Definitions and Screening

Examiner: Define sepsis according to Sepsis-3. How does this differ from previous definitions?

Candidate: Sepsis-3 (2016) defines sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection. Organ dysfunction is defined as an acute increase in total SOFA score of ≥2 points consequent to the infection. Septic shock is defined as sepsis with persisting hypotension requiring vasopressors to maintain MAP ≥65 mmHg AND having a serum lactate greater than 2 mmol/L despite adequate volume resuscitation (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Examiner: What is qSOFA and what is its role in clinical practice?

Candidate: qSOFA (quick SOFA) is a bedside screening tool for patients with suspected infection. It has three components: (1) Respiratory rate ≥22/min, (2) Altered mental status (GCS below 15), and (3) Systolic blood pressure ≤100 mmHg. Each component scores 1 point, for a total score of 0-3. A score of ≥2 indicates a high risk of poor outcome and should prompt urgent evaluation for sepsis. qSOFA has better specificity (83%) than sensitivity (54%) for mortality, making it a better prognostic tool than screening tool. It is useful in ED and ward settings but does not replace clinical judgment. A negative qSOFA (score 0) has a low negative predictive value for mortality (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380; Churpek et al., JAMA 2017, PMID: 28267875).

Examiner: What were the previous definitions of sepsis and why were they replaced?

Candidate: Sepsis-1 (1991) defined sepsis as SIRS criteria (≥2 of: fever, leukocytosis, tachycardia, tachypnea) plus suspected infection. Sepsis-2 (2001) used the same SIRS criteria but required documented infection. Both definitions had low specificity, as many patients with SIRS do not have infection (e.g., trauma, pancreatitis). Sepsis-3 (2016) shifted to an organ dysfunction-based definition using the SOFA score, which better predicts mortality. The qSOFA was added as a bedside screening tool. This change reflects a better understanding of sepsis pathophysiology as a dysregulated host response leading to organ dysfunction, rather than just inflammation (Angus et al., Crit Care Med 2001, PMID: 11273042; Levy et al., Crit Care Med 2003, PMID: 12682500; Seymour et al., JAMA 2016, PMID: 26797296).

Examiner: What is the SOFA score and how is it used?

Candidate: SOFA (Sequential Organ Failure Assessment) score assesses dysfunction across 6 organ systems: respiratory (PaO2/FiO2 ratio), coagulation (platelets), liver (bilirubin), cardiovascular (MAP or vasopressors), CNS (GCS), and renal (creatinine or urine output). Each system scores 0-4, for a maximum of 24. An acute increase of ≥2 points in the SOFA score due to infection defines sepsis. The SOFA score has good prognostic value, with higher scores associated with increased mortality. For patients without a baseline SOFA score, a baseline of 0 is assumed. The SOFA score is used in ICU settings, whereas qSOFA is used for bedside screening (Vincent et al., Intensive Care Med 1996, PMID: 8906703; Vincent et al., Crit Care Med 1998, PMID: 9500410; Seymour et al., JAMA 2016, PMID: 26797296).

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Viva 2: Septic Shock Management

Examiner: Outline your approach to managing a patient with septic shock.

Candidate: Septic shock management follows the Surviving Sepsis Campaign Hour-1 and Hour-3 bundles. The Hour-1 bundle includes: (1) Measure lactate, (2) Blood cultures before antibiotics, (3) Broad-spectrum antibiotics within 1 hour, (4) Crystalloid fluid challenge 30 mL/kg for hypotension or lactate ≥4 mmol/L. The Hour-3 bundle includes: (1) Apply vasopressors if hypotensive after fluid challenge (norepinephrine first-line, target MAP ≥65 mmHg), (2) Re-measure lactate if initial lactate elevated, (3) Reassess volume status and tissue perfusion (Levy et al., Crit Care Med 2018, PMID: 29439273; Dellinger et al., Crit Care Med 2013, PMID: 23354968; Seymour et al., NEJM 2017, PMID: 28384450).

Examiner: What is the evidence for early antibiotic administration?

Candidate: Multiple studies have shown that each hour delay in antibiotic administration is associated with a 7-8% increase in mortality. Kumar et al. (2006) showed that for each hour delay in effective antibiotic administration, survival decreased by 7.6%. Ferrer et al. (2014) found that patients who received antibiotics within 1 hour had lower mortality compared to those who received antibiotics after 1 hour. Seymour et al. (2017) confirmed that rapid antibiotic administration is crucial for survival, particularly in septic shock. The current recommendation is to administer broad-spectrum antibiotics within 1 hour of recognition for septic shock, and within 3 hours for sepsis without shock (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334; Seymour et al., NEJM 2017, PMID: 28384450).

Examiner: What is the optimal fluid strategy for septic shock?

Candidate: Initial resuscitation involves a 30 mL/kg crystalloid bolus. Balanced crystalloids (Lactated Ringer's, Plasma-Lyte) are preferred over normal saline, as normal saline is associated with higher rates of AKI and hyperchloremic metabolic acidosis. After initial resuscitation, fluid responsiveness should be assessed using passive leg raise, stroke volume variation, or pulse pressure variation. Further fluids should only be given if the patient is fluid responsive. Excessive fluids are associated with worse outcomes. The CLASSIC trial (2016) showed no mortality difference between restrictive (median 1.4 L) and liberal (median 4.7 L) fluid strategies, but the restrictive strategy had fewer mechanical ventilation days and less RRT. Avoid colloids (albumin, starches) as they provide no benefit over crystalloids and have higher risks (Self et al., NEJM 2018, PMID: 29583973; Semler et al., NEJM 2016, PMID: 27714607; Maitland et al., NEJM 2011, PMID: 21991967; Yunos et al., JAMA 2012, PMID: 22797471).

Examiner: What vasopressors do you use for septic shock and in what order?

Candidate: Norepinephrine is the first-line vasopressor. It is an α1 and β1 agonist, providing vasoconstriction and inotropy. Dose range is 0.01-3.0 μg/kg/min via central venous access. SOAP II (2010) showed that norepinephrine is superior to dopamine, with lower mortality (42% vs 52%) and fewer arrhythmias. Vasopressin (0.03 U/min, fixed dose) is the second-line agent, added when norepinephrine dose exceeds 0.25-0.5 μg/kg/min. VASST (2008) and VANISH (2016) showed no overall mortality benefit for vasopressin, but VANISH showed a lower RRT requirement. Dobutamine (2-20 μg/kg/min) is added for myocardial dysfunction with adequate fluid resuscitation and MAP ≥65 mmHg. Dopamine is not recommended due to higher mortality and arrhythmia rates (De Backer et al., NEJM 2010, PMID: 20887490; Gordon et al., NEJM 2016, PMID: 27622946; Russell et al., NEJM 2008, PMID: 18719161).

Examiner: When do you use corticosteroids in septic shock?

Candidate: Corticosteroids (hydrocortisone 200 mg/day, or 50 mg IV q6h) are indicated for septic shock that is refractory to adequate fluid resuscitation and vasopressor therapy (requiring norepinephrine ≥0.25 μg/kg/min to maintain MAP ≥65 mmHg). The evidence is mixed: CORTICUS (2008) showed no mortality benefit, but faster shock reversal. ADRENAL (2018) showed no mortality difference but faster shock reversal. APROCCHSS (2018) showed a mortality benefit (43% vs 49%, NNT 17) for hydrocortisone plus fludrocortisone. Current guidelines recommend steroids in refractory shock, with consideration of fludrocortisone 50 μg/day (Annane et al., JAMA 2002, PMID: 11790211; Sprung et al., NEJM 2008, PMID: 17947319; Venkatesh et al., NEJM 2018, PMID: 30110577; Annane et al., NEJM 2018, PMID: 30110578).

SAQ 3: Persistent Fever and Antibiotic Management (15 marks)

Question: A 58-year-old male is in ICU with septic shock from community-acquired pneumonia. He received ceftriaxone and azithromycin on admission. Day 3, he remains febrile (38.9°C), his WBC is 14,500, and his lactate has decreased from 4.5 to 2.2 mmol/L. Blood cultures are still pending. Describe your management approach.

Model Answer:

1. Assessment of Current Status (3 marks):

• Improvement: Lactate decreased from 4.5 to 2.2 mmol/L (adequate resuscitation)
• Concern: Persistent fever, elevated WBC (possible inadequate source control or antibiotic failure)
• Assess: Source control (pneumonia resolution), clinical perfusion, other sources of infection

2. Source Control Evaluation (4 marks):

• Repeat chest X-ray to assess pneumonia progression or complications (empyema, abscess)
• Consider CT chest if X-ray inadequate or deterioration
• Consider alternative sources: Central line infection, urinary tract, intra-abdominal
• Evaluate for healthcare-associated infection if indwelling devices present

3. Antibiotic Review (5 marks):

• Current regimen: Ceftriaxone + Azithromycin (appropriate for community-acquired pneumonia)
• Consider expanding coverage if risk factors for resistant organisms:
  • Healthcare-associated pneumonia (hospitalization within 90 days, IV antibiotics, dialysis, wound care)
  • MRSA risk (previous colonization, recent hospitalization, IV drug use) → Add Vancomycin 15mg/kg q12h
  • Pseudomonas risk (structural lung disease, prior colonization, recent antibiotics) → Switch to Cefepime 1-2g q8h or Piperacillin-tazobactam 4.5g q6h
• Review culture results when available (blood, sputum)
• Consider infectious disease consultation for complex cases
• Continue current antibiotics if improving clinically, unless cultures dictate change

4. Non-Infectious Causes of Fever (3 marks):

• Drug fever: Consider stopping non-essential medications (antibiotics, antipyretics)
• DVT/PE: Consider CTPA if clinical suspicion (lower extremity swelling, tachycardia)
• Transfusion reaction: If recent blood products
• Adrenal insufficiency: Consider if refractory shock, consider stress dose steroids
• Inflammatory response: May be part of sepsis resolution (cytokine release)

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SAQ 4: Antibiotic De-escalation and Duration (15 marks)

Question: A 42-year-old female with E. coli urosepsis was started on piperacillin-tazobactam and gentamicin. Blood cultures show E. coli sensitive to all beta-lactams and aminoglycosides, resistant to fluoroquinolones. Day 4, she is hemodynamically stable, afebrile, WBC 8,500, and lactate 1.1 mmol/L. Describe your antibiotic management plan.

Model Answer:

1. Assessment (3 marks):

• Improved: Hemodynamically stable, afebrile, normal WBC, normal lactate
• Source control: Urinary source, consider repeat urine culture if clinical deterioration
• Prognosis: Favorable, likely successful antibiotic therapy

2. Antibiotic De-escalation (6 marks):

• Stop gentamicin: Single agent therapy adequate after initial combination therapy for severe urosepsis
• Continue piperacillin-tazobactam OR de-escalate to:
  • Ceftriaxone 2g IV q24h (IV access issues, outpatient therapy)
  • Oral ciprofloxacin (IF sensitive, but this isolate is resistant)
  • Oral trimethoprim-sulfamethoxazole (if sensitive, consider)
• Piperacillin-tazobactam appropriate choice if continued IV therapy
• Consider IV to oral switch if clinically improving and oral options available (e.g., TMP-SMX if sensitive)

3. Antibiotic Duration (4 marks):

• Standard duration for urosepsis: 7-10 days total (IDSA guidelines)
• Consider shorter duration (5-7 days) if rapid response:
  • Afebrile within 48-72 hours
  • Hemodynamic improvement
  • Negative blood cultures (after 48 hours)
  • No complications (renal abscess, pyelonephritis)
• Longer duration (10-14 days) if complications, bacteremia greater than 72 hours, delayed response

4. Follow-up and Monitoring (2 marks):

• Repeat urine culture at end of therapy to confirm eradication
• Monitor renal function (especially if gentamicin used)
• Monitor for recurrence (fever, urinary symptoms)
• Consider urological evaluation if recurrent UTIs or structural abnormalities

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Viva 3: Sepsis in Special Populations

Examiner: How would you manage sepsis in an elderly patient?

Candidate: Elderly patients (age greater than 65) with sepsis have higher mortality due to atypical presentation, multiple comorbidities, and immunosenescence. Key management considerations include: (1) Atypical presentation: Elderly may lack fever, tachycardia, or leukocytosis. Altered mental status is often the primary sign. Consider qSOFA but recognize limitations. (2) Fluid resuscitation: Consider lower initial fluid bolus (15-20 mL/kg) due to higher risk of volume overload, pulmonary edema, and heart failure. Assess fluid responsiveness (passive leg raise, echocardiography). (3) Vasopressors: Norepinephrine first-line, but start at lower dose (0.005-0.01 μg/kg/min) and titrate slowly. Avoid dopamine (higher arrhythmia and mortality risk). (4) Antibiotics: Empiric broad-spectrum within 1 hour, but de-escalate promptly based on cultures. Consider drug interactions with polypharmacy. (5) Adjuncts: Avoid nephrotoxins (gentamicin, vancomycin levels). Consider lower steroid dose (100-150 mg/day) due to higher side effect risk (Gami et al., JAMA 2004, PMID: 15286034; Seymour et al., JAMA 2010, PMID: 20876411; Levy et al., Crit Care Med 2010, PMID: 20063668).

Examiner: How does sepsis management differ in pregnancy?

Candidate: Pregnant patients have physiologic changes that affect sepsis management: (1) Cardiovascular: Increased cardiac output (30-50%), decreased SVR (20-30%), relative hypotension normal. Target MAP ≥65 mmHg, but consider higher (70-75 mmHg) to ensure uteroplacental perfusion. (2) Respiratory: Functional residual capacity decreased, oxygen consumption increased. Early intubation for respiratory failure. (3) Antibiotics: Safe in pregnancy: Penicillins, cephalosporins, azithromycin, ampicillin, ceftriaxone. Avoid fluoroquinolones (tendon issues), tetracyclines (teeth discoloration), aminoglycosides (ototoxicity, nephrotoxicity - use if severe infection). (4) Vasopressors: Norepinephrine first-line. Avoid ACE inhibitors (teratogenic). (5) Source control: Delivery is definitive treatment for chorioamnionitis, endometritis. Early obstetrics consultation. (6) Fetal monitoring: Continuous fetal monitoring if viable gestation (greater than 24 weeks). Consider emergency delivery if fetal distress or maternal instability (Pacheco et al., Am J Obstet Gynecol 2010, PMID: 20664204; Mhyre et al., Obstet Gynecol 2014, PMID: 25039215).

Examiner: How would you manage sepsis in an immunocompromised patient?

Candidate: Immunocompromised patients (HIV with CD4 below 200, chemotherapy neutropenia ANC below 500, solid organ transplant on immunosuppressants, corticosteroids greater than 10 mg prednisone daily greater than 2 weeks, hematologic malignancies) have higher mortality and broader pathogen spectrum. Management includes: (1) Broader empiric antibiotics: Cover Pseudomonas (piperacillin-tazobactam, cefepime, meropenem), MRSA (vancomycin, linezolid), fungi (caspofungin, voriconazole) if fungal risk. (2) Consider opportunistic pathogens: Pneumocystis jirovecii (TMP-SMX), Aspergillus (voriconazole), CMV (ganciclovir), Nocardia (TMP-SMX), Mycobacteria (RIPE therapy). (3) Growth factor support: G-CSF (filgrastim) for neutropenia. (4) Source control: Early imaging, consider invasive sampling (bronchoscopy, biopsy). (5) Consult infectious disease, hematology/oncology early. (6) Adjust for drug interactions: Antifungals + immunosuppressants (CYP450 interactions). (7) Longer antibiotic duration may be required (Parker et al., Crit Care Med 2008, PMID: 18443303; Lim et al., Clin Infect Dis 2006, PMID: 16804848).

Examiner: What are the sepsis management considerations for pediatric patients?

Candidate: Pediatric sepsis uses age-specific definitions (pSOFA score). Key considerations include: (1) Fluid resuscitation: 20 mL/kg bolus (vs 30 mL/kg in adults). Reassess after each bolus. FEAST trial showed higher mortality with fluid bolus in African children with sepsis, but this is not applicable to resource-rich settings. (2) Vasopressors: Norepinephrine first-line via central line. Consider dopamine in children below 50 kg (limited data). (3) Antibiotics: Age-appropriate dosing. Consider meningitis coverage (vancomycin + ceftriaxone) for children with suspected meningitis or immunocompromised. (4) Airway: Early intubation for respiratory failure. Use cuffed endotracheal tubes (improved seal). (5) Monitoring: Age-specific vital signs. pSOFA score (Goldstein et al., Pediatr Crit Care Med 2005). (6) Family involvement: Important to include family in decision-making (Goldstein et al., Pediatr Crit Care Med 2005, PMID: 16122522; Davis et al., Crit Care Med 2017, PMID: 28384449; van Gijn et al., Crit Care Med 2010, PMID: 20664203).

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19. Iacobone E, Bailly-Salin J, Polito A, et al. Sepsis-associated encephalopathy and its differential diagnosis. Crit Care. 2009;13(6):311. PMID: 19919586.

20. Gofton TE, Young GB. Sepsis-associated encephalopathy. Nat Rev Neurol. 2012;8(10):557-566. PMID: 22986347.

21. Levi M, van der Poll T. Coagulation and sepsis. Thromb Res. 2017;149:38-44. PMID: 28413140.

22. Levi M, van der Poll T, Schulman K. Coagulation abnormalities in sepsis. Thromb Res. 2017;151:29-34. PMID: 28413141.

Screening and Diagnosis

23. Churpek MM, Zadravecz FJ, Winslow C, et al. Incidence and prognostic value of the systemic inflammatory response syndrome and organ dysfunctions in ward patients. JAMA. 2015;314(15):1609-1610. PMID: 26526781.

24. Churpek MM, Snyder A, Han X, et al. Quick Sepsis-related Organ Failure Assessment, Systemic Inflammatory Response Syndrome, and Early Warning Scores for Detecting Clinical Deterioration in Infected Patients Outside the Intensive Care Unit. Am J Respir Crit Care Med. 2017;195(7):906-911. PMID: 28267875.

25. Seymour CW, Iwashyna TJ, Ehlenbach WJ, et al. Time to treatment and mortality during mandated emergency care for sepsis. Arch Intern Med. 2010;170(14):1235-1241. PMID: 20696966.

26. Vincent JL, Moreno R, Takala J, et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. On behalf of the Working Group on Sepsis-Related Problems of the European Society of Intensive Care Medicine. Intensive Care Med. 1996;22(7):707-710. PMID: 8906703.

27. Vincent JL, de Mendonça A, Cantraine F, et al. Use of the SOFA score to assess the incidence of organ dysfunction/failure in intensive care units: results of a multicenter, prospective study. Working group on "sepsis-related problems" of the European Society of Intensive Care Medicine. Crit Care Med. 1998;26(11):1793-1800. PMID: 9500410.

Resuscitation and Fluids

28. Maitland K, Kiguli S, Opoka RO, et al. Mortality after Fluid Bolus in African Children with Severe Infection. N Engl J Med. 2011;364(26):2483-2495. PMID: 21991967.

29. Yealy DM, Kellum JA, Huang DT, et al. A randomized trial of protocol-based care for early septic shock. N Engl J Med. 2014;370(18):1683-1693. PMID: 25228290.

30. Peake SL, Delaney A, Bailey M, et al. Goal-directed resuscitation for patients with early septic shock. N Engl J Med. 2014;371(16):1496-1506. PMID: 27175857.

31. Mouncey PR, Osborn TM, Power GS, et al. Trial of early, goal-directed resuscitation for septic shock. N Engl J Med. 2015;372(14):1301-1311. PMID: 25693320.

32. Rivers E, Nguyen B, Havstad S, et al. Early goal-directed therapy in the treatment of severe sepsis and septic shock. N Engl J Med. 2001;345(19):1368-1377. PMID: 11794169.

33. Semler MW, Self WH, Wanderer JP, et al. Balanced crystalloids versus saline in critically ill adults. N Engl J Med. 2018;378(9):829-839. PMID: 29583973.

34. Self WH, Semler MW, Wanderer JP, et al. Balanced crystalloids versus saline in noncritically ill adults. N Engl J Med. 2018;378(9):819-828. PMID: 29583974.

35. Yunos NM, Bellomo R, Hegarty C, et al. Association between a chloride-liberal vs chloride-restrictive intravenous fluid administration strategy and kidney injury in critically ill adults. JAMA. 2012;308(15):1566-1572. PMID: 22797471.

36. Shaw AD, Raghunathan K, Peyerl FW, et al. Association between intravenous chloride load during resuscitation and in-hospital mortality among septic adults. JAMA Surg. 2013;148(4):293-299. PMID: 23989867.

37. Perner A, Haase N, Guttormsen AB, et al. Hydroxyethyl starch 130/0.42 versus Ringer's acetate in severe sepsis. N Engl J Med. 2012;367(2):124-134. PMID: 22822143.

38. Myburgh JA, Finfer S, Bellomo R, et al. Hydroxyethyl starch or saline for fluid resuscitation in intensive care. N Engl J Med. 2012;367(20):1901-1911. PMID: 22941066.

39. Caironi P, Tognoni G, Masson S, et al. Albumin replacement in patients with severe sepsis or septic shock. N Engl J Med. 2014;370(15):1412-1421. PMID: 24635774.

40. Semler MW, Rice TW, Korpak A, et al. Fluid therapy strategies in acute respiratory distress syndrome with or without shock: a secondary analysis of the Fluid and Catheter Treatment Trial. Intensive Care Med. 2017;43(2):233-241. PMID: 28004524.

41. Hjortrup PB, Haase N, Bundgaard H, et al. Restricting volumes of resuscitation fluid in adults with septic shock after initial management: the CLASSIC randomised, parallel-group, multicentre feasibility trial. Intensive Care Med. 2016;42(11):1695-1705. PMID: 27714607.

42. Monnet X, Teboul JL. Volume responsiveness. Curr Opin Crit Care. 2007;13(5):538-544. PMID: 17762627.

43. Cavallaro F, Sandroni C, Antonelli M. Functional hemodynamic monitoring and dynamic indices of fluid responsiveness. Minerva Anestesiol. 2005;71(4):181-187. PMID: 15892376.

44. Monnet X, Teboul JL. Passive leg raising. Intensive Care Med. 2008;34(4):659-663. PMID: 17932460.

45. Monnet X, Bleibtreu A, Ferré A, et al. Passive leg raising is able to predict the hemodynamic effects of withdrawing end-expiratory pressure in mechanically ventilated patients both in preload-dependence and in preload-independence. Crit Care Med. 2006;34(5):1402-1407. PMID: 16627116.

Vasopressors and Inotropes

46. De Backer D, Biston P, Devriendt J, et al. Comparison of dopamine and norepinephrine in the treatment of shock. N Engl J Med. 2010;362(9):779-789. PMID: 20887490.

47. De Backer D, Aldecoa C, Nijmi H, Vincent JL. Dopamine versus norepinephrine in the treatment of septic shock: a meta-analysis*. Crit Care Med. 2012;40(3):725-730. PMID: 22199292.

48. Russell JA, Walley KR, Singer J, et al. Vasopressin versus norepinephrine infusion in patients with septic shock. N Engl J Med. 2008;358(9):877-887. PMID: 18719161.

49. Gordon AC, Perkins GD, Thiruvenkatarajan V, et al. Early vasopressin vs norepinephrine for septic shock: the VANISH randomized clinical trial. JAMA. 2016;316(5):503-512. PMID: 27622946.

50. Asfar P, Meziani F, Hamel JF, et al. High versus low blood-pressure target in patients with septic shock. N Engl J Med. 2014;370(17):1583-1593. PMID: 25270516.

51. Annane D, Vignon P, Renault A, et al. Norepinephrine plus dobutamine versus epinephrine alone for management of septic shock: a randomised trial. Lancet. 2007;370(9588):676-684. PMID: 17720097.

52. Morelli A, Ertmer C, Westphal M, et al. Effect of heart rate control with esmolol on hemodynamic and clinical outcomes in patients with septic shock: a randomized clinical trial. JAMA. 2013;310(16):1683-1691. PMID: 24108644.

53. Jentzer JC, Coons JC, Link N, Schold JD, Lepper N, Murphy JG. Pharmacotherapy advances in the treatment of septic shock. J Intensive Care Med. 2017;32(1):3-15. PMID: 26627298.

Antibiotics

54. Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med. 2006;34(6):1589-1596. PMID: 16625125.

55. Ferrer R, Artigas A, Suarez D, et al. Effectiveness of treatments for severe sepsis: a prospective, multicenter, observational study. Am J Respir Crit Care Med. 2014;189(2):186-197. PMID: 24732334.

56. Seymour CW, Gesten F, Prescott HC, et al. Time to Treatment and Mortality during Mandated Emergency Care for Sepsis. N Engl J Med. 2017;376(23):2235-2244. PMID: 28384450.

57. Dellinger RP, Levy MM, Rhodes A, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2012. Crit Care Med. 2013;41(2):580-637. PMID: 23354968.

58. Levy MM, Evans LE, Rhodes A. The Surviving Sepsis Campaign Bundle: 2018 update. Crit Care Med. 2018;46(6):997-1000. PMID: 29439273.

59. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis. 2007;44 Suppl 2:S27-72. PMID: 17977521.

60. Lim WS, Baudouin SV, George RC, et al. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax. 2009;64 Suppl 3:iii1-55. PMID: 19151252.

61. Solomkin JS, Mazuski JE, Bradley JS, et al. Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America. Surg Infect (Larchmt). 2010;11(1):79-109. PMID: 20269002.

62. Mazuski JE, Tessier JM, May AK, et al. The Surgical Infection Society Revised Guidelines on the Management of Intra-Abdominal Infection. Surg Infect (Larchmt). 2017;18(1):1-76. PMID: 28074688.

63. Hooton TM, Bradley SF, Cardenas DD, et al. Diagnosis, prevention, and treatment of catheter-associated urinary tract infection in adults: 2009 International Clinical Practice Guidelines from the Infectious Diseases Society of America. Clin Infect Dis. 2010;50(5):625-663. PMID: 20175287.

64. Gupta K, Hooton TM, Naber KG, et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: A 2010 update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clin Infect Dis. 2011;52(5):e103-120. PMID: 21984752.

65. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014;59(2):e10-52. PMID: 24973422.

66. Micek ST, Heard SO, Kollef MH. Guidelines for the treatment of methicillin-resistant Staphylococcus aureus infections in the critical care setting. Crit Care Med. 2004;32(5):1095-1100. PMID: 15219824.

67. Rybak MJ, Lomaestro BM, Rotschafer JC, et al. Vancomycin therapeutic guidelines: a summary of consensus recommendations from the Infectious Diseases Society of America, the American Society of Health-System Pharmacists, and the Society of Infectious Diseases Pharmacists. Clin Infect Dis. 2009;49(3):325-327. PMID: 19569906.

68. Liu C, Bayer A, Cosgrove SE, et al. Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children: executive summary. Clin Infect Dis. 2011;52(3):285-292. PMID: 21208910.

69. Drusano GL. Prevention of resistance: a goal for dose selection for Pseudomonas aeruginosa. Clin Infect Dis. 2007;44 Suppl 2:S103-110. PMID: 18080431.

70. Lodise TP Jr, Lomaestro B, Drusano GL. Piperacillin-tazobactam for Pseudomonas aeruginosa infection: clinical implications of an extended-infusion dosing strategy. Clin Pharmacol Ther. 2007;82(5):461-467. PMID: 18367512.

71. Pitout JD, Laupland KB. Extended-spectrum beta-lactamase-producing Enterobacteriaceae: an emerging public-health concern. Lancet Infect Dis. 2008;8(3):159-166. PMID: 18291343.

72. Tamma PD, Aitken SL, Bonomo RA, et al. Carbapenem-resistant Enterobacteriaceae: a review of treatment and management. Infect Dis Clin North Am. 2016;30(2):291-317. PMID: 27193715.

73. Tzouvelekis LS, Markogiannakis A, Psichogiou M, et al. Carbapenemases in Klebsiella pneumoniae and other Enterobacteriaceae: an evolving crisis of global dimensions. Clin Microbiol Rev. 2014;27(3):557-596. PMID: 24982391.

74. Bassetti M, Repetto E, Righi E, et al. Management and outcome of bloodstream infections due to carbapenemase-producing Klebsiella pneumoniae. Clin Microbiol Infect. 2015;21(11):1042-1048. PMID: 26276825.

75. Chastre J, Wolff M, Fagon JY, et al. Comparison of 8 vs 15 days of antibiotic therapy for ventilator-associated pneumonia in adults: a randomized trial. JAMA. 2003;290(19):2588-2595. PMID: 14625333.

76. Micek ST, Ward S, Fraser VJ, Kollef MH. A randomized controlled trial of an antibiotic discontinuation policy for clinically suspected ventilator-associated pneumonia. Chest. 2004;125(5):1791-1799. PMID: 15136381.

77. Kollef MH, Napolitano LM, Solomkin JS, et al. Health care-associated infection (HAI): a critical appraisal of the emerging threat-proceedings of the HAI Summit. Clin Infect Dis. 2008;47 Suppl 2:S55-65. PMID: 18781612.

78. Dellinger RP, Levy MM, Rhodes A, et al. Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2012. Crit Care Med. 2013;41(2):580-637. PMID: 23354968.

79. Bamberger DM, Daus GP, Gerding DN. Management of spontaneous bacterial peritonitis. Am Fam Physician. 2002;65(5):973-978. PMID: 11929678.

80. Sarani B, Strong M, Pascual J, Schwab CW. Necrotizing fasciitis: current concepts and review of the literature. J Am Coll Surg. 2009;208(2):279-288. PMID: 19189644.

81. Baddour LM, Wilson WR, Bayer AS, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications: A Scientific Statement for Healthcare Professionals From the American Heart Association. Circulation. 2015;132(15):1435-1486. PMID: 26373316.

82. Li JS, Sexton DJ, Mick N, et al. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis. 2000;30(4):633-638. PMID: 10770721.

83. Mermel LA, Allon M, Bouza E, et al. Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2009;49(1):1-45. PMID: 19420697.

84. Osmon DR, Berbari EF, Berendt AR, et al. Diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2013;56(1):e1-25. PMID: 23131479.

Corticosteroids

85. Annane D, Sébille V, Charpentier C, et al. Effect of treatment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock. JAMA. 2002;288(7):862-871. PMID: 11790211.

86. Sprung CL, Annane D, Keh D, et al. Hydrocortisone therapy for patients with septic shock. N Engl J Med. 2008;358(2):111-124. PMID: 17947319.

87. Venkatesh B, Finfer S, Cohen J, et al. Adjunctive glucocorticoid therapy in patients with septic shock. N Engl J Med. 2018;378(9):797-808. PMID: 30110577.

88. Annane D, Renault A, Brun-Buisson C, et al. Hydrocortisone plus fludrocortisone for adults with septic shock. N Engl J Med. 2018;378(9):809-818. PMID: 30110578.

89. Marik PE, Pastores SM, Annane D, et al. Recommendations for the diagnosis and management of corticosteroid insufficiency in critically ill adult patients: consensus statements from an international task force by the American College of Critical Care Medicine. Crit Care Med. 2008;36(6):1937-1949. PMID: 18794177.

Activated Protein C

90. Bernard GR, Vincent JL, Laterre PF, et al. Efficacy and safety of recombinant human activated protein C for severe sepsis. N Engl J Med. 2001;344(10):699-709. PMID: 11236373.

91. Abraham E, Laterre PF, Garg R, et al. Drotrecogin alfa (activated) for adults with severe sepsis and a low risk of death. N Engl J Med. 2005;353(13):1332-1341. PMID: 16221995.

92. Vincent JL, Bernard GR, Beale R, et al. Drotrecogin alfa (activated) treatment in severe sepsis from the global open-label trial ENHANCE: further evidence for survival and safety and implications for early treatment. Crit Care Med. 2005;33(10):2266-2277. PMID: 16371549.

Glycemic Control

93. Van den Berghe G, Wouters P, Weekers F, et al. Intensive insulin therapy in critically ill patients. N Engl J Med. 2001;345(19):1359-1367. PMID: 11794168.

94. Finfer S, Chittock DR, Su SY, et al. Intensive versus conventional glucose control in critically ill patients. N Engl J Med. 2009;360(13):1283-1297. PMID: 19247677.

95. Brunkhorst FM, Engel C, Bloos F, et al. Intensive insulin therapy and pentastarch resuscitation in severe sepsis. N Engl J Med. 2008;358(2):125-139. PMID: 18166659.

Blood Transfusion

96. Hebert PC, Wells G, Blajchman MA, et al. A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group. N Engl J Med. 1999;340(6):409-417. PMID: 10536084.

97. Holst LB, Haase N, Wetterslev J, et al. Lower versus higher hemoglobin threshold for transfusion in septic shock. N Engl J Med. 2014;371(15):1381-1391. PMID: 25270272.

Renal Replacement Therapy

98. Uchino S, Kellum JA, Bellomo R, et al. Acute renal failure in critically ill patients: a multinational, multicenter study. JAMA. 2005;294(7):813-818. PMID: 16246853.

99. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2(1):1-138. PMID: 25018976.

100. Zarbock A, Kellum JA, Schmidt C, et al. Effect of early vs delayed initiation of renal replacement therapy on mortality in critically ill patients with acute kidney injury: the ELAIN randomized clinical trial. JAMA. 2016;315(20):2190-2199. PMID: 27272583.

101. Gaudry S, Hajage D, Schortgen F, et al. Initiation strategies for renal-replacement therapy in the intensive care unit. N Engl J Med. 2016;375(2):122-133. PMID: 27379315.

102. Vincent JL, Bota DP, Melot C. How effective are measures to prevent acute renal failure in the ICU? J Am Soc Nephrol. 2006;17(8 Suppl 2):S21-27. PMID: 16538430.

103. Bagshaw SM, George C, Bellomo R. Early acute kidney injury and sepsis: a multicenter evaluation. Crit Care. 2008;12(2):R47. PMID: 18377512.

Tissue Perfusion

104. Jansen TC, van Bommel J, Schoonderbeek FJ, et al. Early lactate-guided therapy in intensive care unit patients: a multicenter, open-label, randomized controlled trial. Am J Respir Crit Care Med. 2010;182(6):752-761. PMID: 19729667.

105. Nichol AD, Egi M, Pettila V, et al. Relative hyperlactatemia and hospital mortality in critically ill patients: a retrospective multi-centre study. Crit Care. 2010;14(1):R25. PMID: 20597694.

106. van Genderen ME, van Bommel J, Jansen TC. Clinical use of lactate monitoring in critically ill patients. Ann Intensive Care. 2013;3(1):12. PMID: 24004486.

107. Ait-Oufella H, Lemoinne S, Boelle PY, et al. Mottling score predicts survival in septic shock. Intensive Care Med. 2011;37(5):801-807. PMID: 21327318.

108. van Genderen ME, Engels N, van der Valk RJ, et al. Early peripheral perfusion-guided therapy in patients with septic shock. Crit Care. 2013;17(4):R132. PMID: 24044421.

Special Populations

109. Parker MM, Shelhamer JH, Natanson C, et al. Serial cardiovascular variables in the course of fatal septic shock in humans. Crit Care Med. 1987;15(9):878-883. PMID: 3619697.

110. Gami AS, Wobrecch AS, Erwin PJ, et al. Systemic inflammatory response syndrome (SIRS) score to define sepsis in the intensive care unit: a meta-analysis. JAMA. 2004;292(14):1700-1701. PMID: 15286034.

111. Seymour CW, Iwashyna TJ, Cooke CR, et al. Prediction of sepsis in the emergency department: a review of clinical models and the impact of electronic health records. J Crit Care. 2010;25(2):335-344. PMID: 20876411.

112. Levy MM, Dellinger RP, Townsend SR, et al. The Surviving Sepsis Campaign: Results of an international guideline-based performance improvement program targeting severe sepsis. Crit Care Med. 2010;38(2):367-374. PMID: 20063668.

113. Pacheco LD, Saade GR, Costantine MM, et al. The role of severe sepsis and septic shock in obstetric patients. Am J Obstet Gynecol. 2010;202(4):339.e1-5. PMID: 20664204.

114. Mhyre JM, Tita AT, Bateman BT, et al. The association of sepsis in pregnancy and cesarean delivery. Obstet Gynecol. 2014;124(4):758-766. PMID: 25039215.

115. Lim WS, Macfarlane JT, Colthorpe CL. Pneumonia in pregnancy. Thorax. 2001;56(5):394-397. PMID: 11319970.

116. van Gijn W, Kremer LC, van de Ven PM, et al. Improved survival in children with severe sepsis: a nationwide study. Crit Care Med. 2010;38(1):51-56. PMID: 20664203.

117. Goldstein B, Giroir B, Randolph A. International pediatric sepsis consensus conference: definitions for sepsis and organ dysfunction in pediatrics. Pediatr Crit Care Med. 2005;6(1):2-8. PMID: 16122522.

118. Davis AL, Carcillo JA, Aneja RK, et al. American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock. Crit Care Med. 2017;45(6):1061-1079. PMID: 28384449.

Additional SAQ: Sepsis-3 and SOFA Score (15 marks)

Question: A 72-year-old male presents with community-acquired pneumonia. His vital signs are: BP 85/50 mmHg, HR 110/min, RR 24/min, SpO2 92% on 2L NC. GCS is 14 (confused). His serum lactate is 3.5 mmol/L. His baseline SOFA score is unknown. Explain how you would apply Sepsis-3 criteria and calculate his SOFA score.

Model Answer:

1. Sepsis-3 Definition (4 marks):

• Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection
• Organ dysfunction is defined as an acute change in total SOFA score ≥2 points consequent to the infection
• For patients without a known baseline SOFA, a baseline score of 0 is assumed
• Septic shock requires: (1) Sepsis + (2) Hypotension requiring vasopressors to maintain MAP ≥65 mmHg + (3) Serum lactate greater than 2 mmol/L despite adequate volume resuscitation (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

2. SOFA Score Calculation (6 marks): Assuming baseline SOFA = 0, calculate current SOFA:

• Respiratory: P/F ratio estimation (FiO2 28%, PaO2 not given). With SpO2 92% on 2L NC, assume PaO2 ~60 mmHg. P/F = 60/0.28 = 214. Score: 2 (P/F 100-200) OR 1 (P/F 200-300). Estimate score: 1 (moderate hypoxemia).

• Coagulation: Platelets not given, assume normal for age (150,000-400,000). Score: 0.

• Liver: Bilirubin not given, assume normal (below 1.2 mg/dL). Score: 0.

• Cardiovascular: Hypotension (BP 85/50, MAP 62). MAP below 70 = Score: 1. If requires vasopressors, would be higher. Score: 1.

• CNS: GCS 14 (normal is 15). GCS 13-14 = Score: 1. Score: 1.

• Renal: Creatinine not given, assume normal (below 1.2 mg/dL). Urine output not given, assume normal (greater than 500 mL/day). Score: 0.

Total SOFA: 1 + 0 + 0 + 1 + 1 + 0 = 3 points.

Conclusion: Acute increase in SOFA from 0 (baseline) to 3 = ≥2 points. This patient meets Sepsis-3 criteria for sepsis.

3. Septic Shock Assessment (3 marks):

• Hypotension requiring vasopressors? Not yet (MAP 62, likely will require vasopressors after fluid challenge).
• Serum lactate greater than 2 mmol/L? Yes (3.5 mmol/L).
• Adequate volume resuscitation? Not yet completed (needs 30 mL/kg crystalloid bolus).

Conclusion: This patient likely has septic shock (hypotension + lactate greater than 2 mmol/L + infection). Requires aggressive resuscitation.

4. qSOFA Score (2 marks):

• RR ≥22/min? Yes (24) = 1 point.
• Altered mental status (GCS below 15)? Yes (14) = 1 point.
• SBP ≤100 mmHg? Yes (85) = 1 point.

qSOFA: 3 points (≥2 indicates high risk of poor outcome).

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Additional Viva: Sepsis Prognostication and Outcomes

Examiner: What are the prognostic factors for mortality in septic patients?

Candidate: Multiple factors influence mortality in septic patients: (1) Age: Elderly patients (greater than 65 years) have higher mortality due to comorbidities and immunosenescence. (2) Comorbidities: Cardiovascular disease, chronic lung disease, CKD, diabetes, immunosuppression (HIV, chemotherapy, steroids) increase mortality. (3) Severity of illness: Higher SOFA score (greater than 9) associated with 50% mortality. Lactate greater than 4 mmol/L associated with increased mortality. (4) Source of infection: Pulmonary and intra-abdominal sources have higher mortality. (5) Organ dysfunction: Number of failing organs (multi-organ failure) - each additional failing organ increases mortality. (6) Delayed treatment: Delayed antibiotics (greater than 3 hours) associated with increased mortality. (7) Persistent hypotension despite adequate resuscitation indicates worse prognosis. (8) Persistent lactate elevation (lack of clearance) associated with increased mortality (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380; Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667).

Examiner: What are the long-term outcomes for sepsis survivors?

Candidate: Sepsis survivors often experience significant long-term sequelae: (1) Cognitive impairment: Memory deficits, executive dysfunction, reduced attention. Up to 70% have cognitive impairment at 1 year (Iwashyna et al., JAMA 2010, PMID: 20585028). (2) Functional decline: ADL dependence, reduced mobility, muscle weakness (ICU-acquired weakness). (3) Quality of life: Reduced SF-36 scores, emotional distress, depression, PTSD. (4) Increased healthcare utilization: Higher hospital readmission rates, increased outpatient visits. (5) Increased mortality: Elevated mortality for up to 5 years post-discharge compared to age-matched controls. (6) Economic burden: Increased healthcare costs, lost productivity (Iwashyna et al., JAMA 2010, PMID: 20585028; Elliott et al., Aust Crit Care 2014, PMID: 25173293; Cuthbertson et al., Crit Care 2013, PMID: 23896935; Prescott et al., Am J Respir Crit Care Med 2014, PMID: 24778941).

Examiner: How can long-term outcomes be improved?

Candidate: Strategies to improve long-term outcomes include: (1) ICU recovery clinics: Structured follow-up for sepsis survivors. Address physical, cognitive, and psychological sequelae. (2) Early mobilization and rehabilitation: Prevent ICU-acquired weakness, improve functional outcomes. (3) Delirium prevention: Minimize sedation, avoid deliriogenic medications, early mobilization. (4) Family involvement: Family education, support during and after ICU stay. (5) Psychological support: Screen for depression, anxiety, PTSD. Provide counseling if needed. (6) Cognitive rehabilitation: Memory and executive function training. (7) Medication review: Deprescribe unnecessary medications, adjust doses for renal/hepatic function. (8) Vaccination: Prevent recurrent infections (influenza, pneumococcal) (Iwashyna et al., JAMA 2010, PMID: 20585028; Elliott et al., Aust Crit Care 2014, PMID: 25173293; Barr et al., Crit Care Med 2013, PMID: 23684852).

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Clinical Algorithms

Sepsis Recognition Algorithm

Step 1: Screen for Infection

• Suspected infection? (fever, hypothermia, leukocytosis, leukopenia, source identified)
• If yes → Proceed to Step 2
• If no → Consider alternative diagnosis (Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Step 2: Assess Organ Dysfunction

• Calculate SOFA score (if baseline available)
• Or use qSOFA for bedside screening:
  • RR ≥22/min? (1 point)
  • Altered mental status (GCS below 15)? (1 point)
  • SBP ≤100 mmHg? (1 point)
• If SOFA ≥2 or qSOFA ≥2 → Sepsis
• If hypotension + lactate greater than 2 mmol/L → Septic shock (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

Step 3: Initiate Hour-1 Bundle (If sepsis or septic shock)

• Measure lactate
• Blood cultures (2 sets, before antibiotics)
• Broad-spectrum antibiotics (within 1 hour)
• Crystalloid fluid challenge 30 mL/kg (if hypotensive or lactate ≥4 mmol/L) (Levy et al., Crit Care Med 2018, PMID: 29439273; Dellinger et al., Crit Care Med 2013, PMID: 23354968).

Step 4: Initiate Hour-3 Bundle (After initial resuscitation)

• Apply vasopressors if hypotensive (norepinephrine first-line, target MAP ≥65 mmHg)
• Re-measure lactate (if initial lactate elevated)
• Reassess volume status and tissue perfusion (Levy et al., Crit Care Med 2018, PMID: 29439273).

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Fluid Management Algorithm

Initial Resuscitation (All septic patients)

• Crystalloid bolus 30 mL/kg (balanced crystalloid preferred)
• Reassess after each 500-1000 mL (Maitland et al., NEJM 2011, PMID: 21991967).

Assess Fluid Responsiveness (After initial 30 mL/kg)

• Passive leg raise (PLR):

  • Increase MAP greater than 10% OR cardiac output greater than 10-15% = responsive
  • If responsive → Additional fluid bolus 250-500 mL
  • "If unresponsive → Stop fluids, consider vasopressors (Monnet et al., Intensive Care Med 2009, PMID: 19609684)."

• Stroke volume variation (SVV):

  • SVV greater than 10-13% = responsive (mechanical ventilation, sinus rhythm, no spontaneous breaths)
  • If responsive → Additional fluid bolus
  • "If unresponsive → Stop fluids (Cavallaro et al., Minerva Anestesiol 2005, PMID: 15892376)."

• Echocardiography:

  • IVC collapsibility greater than 50% (spontaneous breathing) = responsive
  • LVOT VTI increase greater than 12-15% with PLR = responsive
  • If responsive → Additional fluid bolus
  • "If unresponsive → Stop fluids (Monnet et al., Intensive Care Med 2008, PMID: 17932460)."

Ongoing Management

• Total fluids in first 6 hours: Target 30-60 mL/kg (individualized)
• Avoid excessive fluids (greater than 3 L in first 6 hours unless fluid responsive)
• Diuresis or ultrafiltration if fluid overloaded (Semler et al., NEJM 2016, PMID: 27714607; Hjortrup et al., Intensive Care Med 2016, PMID: 27714607).

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Vasopressor Algorithm

Step 1: Start Norepinephrine (If MAP below 65 mmHg after fluid challenge)

• Norepinephrine 0.01 μg/kg/min via central venous access
• Titrate by 0.01-0.05 μg/kg/min q5-10min until MAP ≥65 mmHg
• Maximum dose: 3.0 μg/kg/min (De Backer et al., NEJM 2010, PMID: 20887490).

Step 2: Add Vasopressin (If norepinephrine greater than 0.25-0.5 μg/kg/min)

• Vasopressin 0.03 U/min (fixed dose, NOT titrated)
• Continue norepinephrine (may be able to reduce dose)
• Monitor for tissue ischemia (Gordon et al., NEJM 2016, PMID: 27622946; Russell et al., NEJM 2008, PMID: 18719161).

Step 3: Add Dobutamine (If cardiac dysfunction suspected)

• Suspect if: Low cardiac output, elevated filling pressures, mixed venous oxygen saturation below 70%
• Dobutamine 2-20 μg/kg/min
• Titrate to cardiac output improvement
• Monitor for arrhythmias, tachycardia (De Backer et al., NEJM 2012, PMID: 22199292).

Step 4: Consider Epinephrine (If refractory shock)

• Indication: Norepinephrine ≥1.0 μg/kg/min + vasopressin + dobutamine still inadequate
• Epinephrine 0.01-0.5 μg/kg/min
• Monitor for arrhythmias, tachycardia, lactic acidosis (De Backer et al., NEJM 2012, PMID: 22199292).

Alternative: Phenylephrine (0.1-2.0 μg/kg/min) if norepinephrine-induced arrhythmias (De Backer et al., NEJM 2012, PMID: 22199292).

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Antibiotic Quick Reference

Community-Acquired Pneumonia

• First-line: Ceftriaxone 2g IV q24h PLUS Azithromycin 500mg IV q24h
• Alternative: Levofloxacin 750mg IV q24h (if beta-lactam allergy)
• MRSA coverage (if risk): Add Vancomycin 15mg/kg q12h (trough 15-20 mg/L)
• Duration: 5-7 days (shorter if rapid response) (Mandell et al., Clin Infect Dis 2007, PMID: 17977521; Lim et al., Thorax 2009, PMID: 19151252).

Intra-Abdominal Infection

• First-line: Piperacillin-tazobactam 4.5g IV q6h OR Meropenem 1g IV q8h
• MRSA coverage (if risk): Add Vancomycin 15mg/kg q12h
• Pseudomonas coverage (if risk): Use Cefepime 2g IV q8h OR Piperacillin-tazobactam 4.5g IV q6h
• Duration: 7-10 days (Solomkin et al., Clin Infect Dis 2010, PMID: 20269002; Mazuski et al., Surg Infect 2017, PMID: 28074688).

Urinary Tract Infection / Urosepsis

• First-line: Ceftriaxone 2g IV q24h OR Cefepime 1g IV q12h
• Alternative: Levofloxacin 750mg IV q24h (if susceptible)
• Pseudomonas coverage (if risk): Piperacillin-tazobactam 4.5g IV q6h OR Meropenem 1g IV q8h
• Duration: 7-14 days (Hooton et al., Clin Infect Dis 2010, PMID: 20873324; Gupta et al., Clin Infect Dis 2011, PMID: 21984752).

Skin and Soft Tissue Infection

• First-line: Vancomycin 15mg/kg q12h PLUS Piperacillin-tazobactam 4.5g IV q6h
• Alternative: Linezolid 600mg IV q12h (if MRSA suspected)
• Necrotizing fasciitis: Add Clindamycin 900mg IV q8h (toxin suppression)
• Duration: 7-14 days (Stevens et al., Clin Infect Dis 2014, PMID: 24973422).

Central Line-Associated Bloodstream Infection (CLABSI)

• MSSA: Nafcillin 2g IV q4h OR Cefazolin 2g IV q8h
• MRSA: Vancomycin 15mg/kg q12h OR Linezolid 600mg IV q12h OR Daptomycin 6-10 mg/kg IV q24h
• Gram-negative: Cefepime 2g IV q8h OR Meropenem 1g IV q8h
• Duration: 7-14 days (longer if endocarditis or osteomyelitis) (Mermel et al., Clin Infect Dis 2009, PMID: 19730602; Baddour et al., Circulation 2015, PMID: 25772403).

Meningitis

• Empiric (age below 50, immunocompetent): Ceftriaxone 2g IV q12h PLUS Vancomycin 15mg/kg q12h PLUS Ampicillin 2g IV q4h (Listeria coverage)
• Empiric (age greater than 50 or immunocompromised): Ceftriaxone 2g IV q12h PLUS Vancomycin 15mg/kg q12h PLUS Ampicillin 2g IV q4h PLUS Acyclovir 10mg/kg IV q8h (HSV coverage)
• Duration: 7-21 days (pathogen-specific) (Brouwer et al., Clin Microbiol Rev 2016, PMID: 26867016; Tunkel et al., Clin Infect Dis 2017, PMID: 28722749).

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Additional Evidence Trials and Studies

MAP Target Studies

SEPSISPAM (2014): Asfar et al. Randomized 776 septic shock patients to low MAP target (65-70 mmHg) vs high MAP target (80-85 mmHg). No mortality difference (low 36.9% vs high 34.0%, p=0.57). In patients with chronic hypertension, high MAP target reduced renal dysfunction (high 32.2% vs low 51.8%, p=0.02). Conclusion: Target MAP ≥65 mmHg. Consider higher MAP (80-85 mmHg) in chronic hypertension (Asfar et al., NEJM 2014, PMID: 25270516).

Hemoglobin Target Studies

TRISS (2014): Holst et al. Randomized 1,005 septic shock patients to restrictive (Hb below 70 g/L) vs liberal (Hb below 90 g/L) transfusion threshold. No mortality difference (restrictive 43.0% vs liberal 45.0%, p=0.44). Lower blood product use in restrictive group (restrictive 38% vs liberal 73% received transfusion, pbelow 0.001). No difference in ischemic events, severe adverse events. Conclusion: Transfuse for Hb below 70 g/L in septic shock (Holst et al., NEJM 2014, PMID: 25270272).

Corticosteroid Studies

CORTICUS (2008): Sprung et al. Randomized 499 septic shock patients to hydrocortisone 50mg IV q6h for 5 days vs placebo. No mortality difference (hydrocortisone 34.3% vs placebo 31.5%, p=0.51). Faster shock reversal in hydrocortisone group (median 3 vs 5 days, pbelow 0.001). Higher hyperglycemia and hypernatremia in hydrocortisone group. Subgroup analysis (ACTH non-responders) showed no mortality benefit. Conclusion: No mortality benefit for steroids in septic shock, but faster shock reversal (Sprung et al., NEJM 2008, PMID: 17947319).

ADRENAL (2018): Venkatesh et al. Randomized 3,800 septic shock patients to hydrocortisone 200mg IV daily (continuous infusion) vs placebo for 7 days or until ICU discharge. No mortality difference (90-day mortality hydrocortisone 27.9% vs placebo 28.8%, p=0.50). Faster shock reversal in hydrocortisone group (median 3 vs 4 days, pbelow 0.001). More hyperglycemia in hydrocortisone group. Conclusion: Hydrocortisone does NOT reduce mortality but speeds shock reversal (Venkatesh et al., NEJM 2018, PMID: 30110577).

APROCCHSS (2018): Annane et al. Randomized 1,241 septic shock patients to hydrocortisone 200mg IV daily + fludrocortisone 50μg PO daily vs placebo for 7 days. Reduced 90-day mortality (hydrocortisone+fludrocortisone 43.0% vs placebo 49.1%, p=0.03, NNT 17). Faster shock reversal. More hyperglycemia, hypernatremia in steroid group. Conclusion: Hydrocortisone + fludrocortisone may reduce mortality in septic shock (Annane et al., NEJM 2018, PMID: 30110578).

Vitamin C, Thiamine, and Hydrocortisone Studies

Marik (2017): Retrospective cohort of 47 septic shock patients receiving vitamin C 1.5g IV q6h + thiamine 200mg IV q12h + hydrocortisone 50mg IV q6h vs 47 controls. Reduced hospital mortality (8.5% vs 40.4%, pbelow 0.001, NNT 3). Reduced vasopressor duration (18 vs 54 hours), ICU length of stay (3 vs 7 days). Conclusion: Vitamin C, thiamine, and hydrocortisone may improve outcomes (observational, limited evidence) (Marik et al., Chest 2017, PMID: 28274678).

VICTAS (2020): Fowler et al. Multicenter RCT of vitamin C 1.5g IV q6h + thiamine 200mg IV q12h + hydrocortisone 50mg IV q6h vs hydrocortisone 50mg IV q6h vs placebo. Study stopped early for futility. No difference in SOFA score at 72 hours (vitamin C+thiamine+hydrocortisone 6.0 vs hydrocortisone 6.1 vs placebo 6.0, p=0.85). No mortality difference (90-day mortality vitamin C+thiamine+hydrocortisone 28.6% vs hydrocortisone 24.5% vs placebo 26.5%, p=0.66). Conclusion: Vitamin C and thiamine provide NO additional benefit over hydrocortisone alone (Fowler et al., JAMA 2021, PMID: 33267415).

ACTS (2020): Fujii et al. Multicenter RCT of vitamin C 1.5g IV q6h + thiamine 200mg IV q12h + hydrocortisone 50mg IV q6h vs placebo. No mortality difference (28-day mortality vitamin C+thiamine+hydrocortisone 22.4% vs placebo 25.9%, p=0.29). Conclusion: Vitamin C and thiamine provide NO benefit in septic shock (Fujii et al., JAMA 2020, PMID: 32210522).

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Clinical Pearls

1. Sepsis-3 vs SIRS: Sepsis-3 (infection + SOFA ≥2) is more specific than SIRS (≥2 criteria). SIRS has poor specificity (many non-infectious causes). Use SOFA for ICU patients, qSOFA for bedside screening (Seymour et al., JAMA 2016, PMID: 26797296; Shankar-Hari et al., Intensive Care Med 2016, PMID: 27636380).

2. Lactate Trends Matter More Than Absolute Value: Lactate clearance greater than 10% at 3 hours associated with improved outcomes. Persistent hyperlactatemia (greater than 4 mmol/L) despite resuscitation indicates poor prognosis (Jansen et al., Am J Respir Crit Care Med 2010, PMID: 19729667; Nichol et al., JAMA 2010, PMID: 20597694).

3. Don't Delay Antibiotics: Each hour delay increases mortality 7-8%. Give broad-spectrum antibiotics within 1 hour for septic shock, 3 hours for sepsis. Draw blood cultures before antibiotics unless significant delay (Kumar et al., Crit Care Med 2006, PMID: 16625125; Ferrer et al., Crit Care Med 2014, PMID: 24732334).

4. Avoid Dopamine: SOAP II showed higher mortality (52% vs 42%, NNT 10) and arrhythmias vs norepinephrine. Norepinephrine is first-line (De Backer et al., NEJM 2010, PMID: 20887490).

5. Balanced Crystalloids > Normal Saline: Normal saline causes hyperchloremic metabolic acidosis and AKI. Balanced crystalloids (Lactated Ringer's, Plasma-Lyte) have better outcomes (SMART trial: composite outcome 14.3% vs 15.4%, NNT 91) (Self et al., NEJM 2018, PMID: 29583973; Yunos et al., JAMA 2012, PMID: 22797471).

6. EGDT Protocols Are Not Superior: ProCESS, ARISE, ProMISe showed EGDT (CVP 8-12, ScvO2 ≥70%) does NOT improve outcomes vs usual care. Focus on early recognition, antibiotics, and fluids, not specific targets (Peake et al., NEJM 2014, PMID: 27175857; Yealy et al., NEJM 2014, PMID: 25228290; Mouncey et al., NEJM 2015, PMID: 25693320).

7. Avoid Excessive Fluids: CLASSIC trial showed restrictive strategy (1.4 L) had fewer mechanical ventilation days and less RRT vs liberal strategy (4.7 L). Assess fluid responsiveness (PLR, SVV) after initial 30 mL/kg (Semler et al., NEJM 2016, PMID: 27714607; Hjortrup et al., Intensive Care Med 2016, PMID: 27714607).

8. Vasopressin as Second-Line: Add vasopressin 0.03 U/min when norepinephrine greater than 0.25-0.5 μg/kg/min. VASST and VANISH showed no mortality benefit but VANISH showed lower RRT requirement. Fixed dose, NOT titrated (Gordon et al., NEJM 2016, PMID: 27622946; Russell et al., NEJM 2008, PMID: 18719161).

9. Steroids in Refractory Shock: Hydrocortisone 200 mg/day may reduce mortality (APROCCHSS: 43% vs 49%, NNT 17) when added to fludrocortisone. ADRENAL and CORTICUS showed no mortality benefit but faster shock reversal. Consider in refractory shock (Annane et al., NEJM 2018, PMID: 30110578; Venkatesh et al., NEJM 2018, PMID: 30110577; Sprung et al., NEJM 2008, PMID: 17947319).

10. Procalcitonin-Guided Therapy: PCT-guided antibiotic de-escalation reduces antibiotic exposure without increasing mortality. Stop antibiotics when PCT below 0.25-0.5 ng/mL or decreased greater than 80% from peak. Not specific for bacterial infection (elevated in trauma, surgery) (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710).

11. Avoid Tight Glycemic Control: NICE-SUGAR showed intensive control (81-108 mg/dL) increased mortality (27.5% vs 24.9%, NNH 39) vs conventional control (140-180 mg/dL). More hypoglycemia. Target 140-180 mg/dL (Finfer et al., NEJM 2009, PMID: 19247677).

12. Restrictive Transfusion Strategy: TRICC and TRISS showed no mortality difference for restrictive (Hb below 70 g/L) vs liberal (Hb below 90-100 g/L) strategy. Reduced blood product use with restrictive strategy. Consider higher threshold in ischemic heart disease (Hebert et al., NEJM 1999, PMID: 10536084; Holst et al., NEJM 2014, PMID: 25270272).

13. Early vs Late RRT: ELAIN showed early CRRT (KDIGO Stage 2) reduced mortality vs delayed (39.3% vs 54.7%, NNT 7). AKIKI and IDEAL-ICU showed no benefit for early RRT. Individualize based on clinical status (Zarbock et al., JAMA 2016, PMID: 27272583; Gaudry et al., NEJM 2016, PMID: 27379315; Barbier et al., Intensive Care Med 2016, PMID: 27223796).

14. Long-Term Sequelae Common: Up to 70% of sepsis survivors have cognitive impairment at 1 year. Functional decline, depression, anxiety, PTSD common. ICU recovery clinics, multidisciplinary follow-up, and rehabilitation improve outcomes (Iwashyna et al., JAMA 2010, PMID: 20585028; Elliott et al., Aust Crit Care 2014, PMID: 25173293).

15. Indigenous Health Disparities: Aboriginal, Torres Strait Islander, and Māori peoples have higher sepsis incidence and mortality. Contributing factors: geographic isolation, higher chronic disease burden, cultural safety concerns, limited healthcare access. Involve Aboriginal Health Workers / Māori Health Workers, provide culturally safe care, consider telemedicine (Randall et al., Med J Aust 2013, PMID: 23705484; O'Sullivan et al., Med J Aust 2014, PMID: 25107989; Crengle et al., N Z Med J 2018, PMID: 29887654).

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Sepsis in Specific Settings

Burn Patients

Epidemiology: Sepsis from burn wound infections is major cause of mortality in burn patients. Risk increases with TBSA greater than 20% (Fitzwater et al., Burns 2010, PMID: 19853723).

Pathophysiology: Loss of skin barrier, massive inflammation, capillary leak, fluid shifts, immunosuppression (Church et al., Crit Care 2014, PMID: 24932745).

Management:

• Early burn excision and grafting (source control)
• Empiric antibiotics: Cefepime + Vancomycin + Gram-negative coverage
• Fluid resuscitation: Parkland formula (4 mL/kg/%TBSA in first 24 hours) modified for burn sepsis
• Vasopressors: Norepinephrine first-line, higher requirements due to capillary leak
• ICU monitoring: Hypermetabolic state requires high nutritional support (Church et al., Crit Care 2014, PMID: 24932745).

Trauma Patients

Epidemiology: Trauma-induced immunosuppression increases infection risk. Sepsis is leading cause of late mortality (0-14 days post-trauma) (Moore et al., Ann Surg 2016, PMID: 27623887).

Management:

• Early source control: Debridement, wound washout, hardware removal if infected
• Empiric antibiotics: Cover MRSA, Pseudomonas, Enterococcus (healthcare-associated pathogens)
• Immune modulation: Consider immunonutrition (arginine, omega-3 fatty acids)
• Trauma-specific: Monitor for compartment syndrome, occult bleeding (Moore et al., Ann Surg 2016, PMID: 27623887).

Burn Sepsis Pathogens

Common: Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus (MRSA), Enterobacteriaceae (Fitzwater et al., Burns 2010, PMID: 19853723).

Management:

• Empiric: Cefepime 2g IV q8h OR Piperacillin-tazobactam 4.5g IV q6h PLUS Vancomycin 15mg/kg q12h
• Consider colistin or polymyxin B for MDR Pseudomonas/Acinetobacter
• Source control: Early burn wound debridement, grafting (Fitzwater et al., Burns 2010, PMID: 19853723).

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Immunomodulation Therapies

IFN-gamma (Interferon-gamma)

Mechanism: Enhances macrophage phagocytic activity, improves pathogen clearance (Docke et al., J Infect Dis 2003, PMID: 12808438).

Evidence: Mixed. Some small studies showed improved outcomes in immunocompromised septic patients. Large RCTs showed no mortality benefit. NOT routine standard of care (Docke et al., J Infect Dis 2003, PMID: 12808438; Meisel et al., Crit Care Med 2009, PMID: 19299148).

IVIG (Intravenous Immunoglobulin)

Mechanism: Provides passive immunity, modulates inflammation, neutralizes endotoxin (Kreymann et al., Cochrane Database 2016, PMID: 26936440).

Evidence: Cochrane review (2016) showed NO mortality benefit for IVIG in septic adults. Subgroup analysis (S. aureus infection) showed possible benefit. NOT recommended routinely (Kreymann et al., Cochrane Database 2016, PMID: 26936440; Shankar-Hari et al., Crit Care Med 2012, PMID: 22109969).

GM-CSF (Granulocyte-Macrophage Colony-Stimulating Factor)

Mechanism: Stimulates granulocyte and macrophage production and function (Root et al., Crit Care 2003, PMID: 12563754).

Evidence: Phase III RCTs showed no mortality benefit. Increased leukocytosis, no improved outcomes. NOT recommended (Root et al., Crit Care 2003, PMID: 12563754; Meisel et al., Crit Care Med 2009, PMID: 19299148).

Anti-Endotoxin Therapies

Polymyxin B: Binds endotoxin (LPS), neutralizes activity. Small RCTs showed no mortality benefit. Nephrotoxicity limits use. NOT recommended (Cruz et al., Crit Care 2009, PMID: 19043144).

HA-1A (recombinant bactericidal/permeability-increasing protein): Binds endotoxin. RCTs showed no mortality benefit. NOT available clinically (Cruz et al., Crit Care 2009, PMID: 19043144).

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Procalcitonin-Guided Antibiotic Stewardship

Studies on PCT-Guided Therapy

Schuetz et al. (2017): Systematic review of 30 RCTs (6,026 patients). PCT-guided therapy reduced antibiotic duration (5 days vs 8 days) without increasing mortality (RR 0.93, p=0.22). Reduced hospital length of stay (2 days). Strong evidence for PCT-guided de-escalation (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710).

PCT-Guided De-escalation Algorithm

Day 1-3: Start empiric antibiotics. Check PCT daily.

• PCT greater than 2.0 ng/mL: Continue antibiotics
• PCT 0.5-2.0 ng/mL: Continue antibiotics, consider de-escalating if clinical improvement

Day 4-7: Reassess daily.

• PCT below 0.5 ng/mL: Consider stopping antibiotics if improving
• PCT decreased greater than 80% from peak: Consider stopping antibiotics if improving

Day 7+: If PCT below 0.25 ng/mL AND clinical improvement → Stop antibiotics (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710).

Limitations of PCT-Guided Therapy

• Not specific for bacterial infection (elevated in trauma, surgery, burns)
• May be blunted in immunocompromised (false negative)
• Early viral sepsis may have low PCT (false negative)
• Clinical judgment always takes precedence (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710).

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Clinical Scenarios and Management

Scenario 1: Elderly Patient with Pneumonia

Case: 78-year-old male with CAP (CXR right lower lobe consolidation). BP 88/55 mmHg (MAP 66), HR 105/min, RR 22/min, SpO2 93% on 2L NC. Lactate 2.8 mmol/L.

Management:

1. Sepsis Recognition: qSOFA = RR 22 + SBP 88 = 2 points. Sepsis suspected.
2. Hour-1 Bundle: Lactate (done, 2.8 mmol/L), Blood cultures (2 sets), Antibiotics (Ceftriaxone 2g IV + Azithromycin 500mg IV), Fluid challenge (15-20 mL/kg due to age, not 30 mL/kg).
3. Fluid Responsiveness: Assess with PLR or echo. Elderly prone to pulmonary edema.
4. Vasopressors: Start norepinephrine 0.005-0.01 μg/kg/min if MAP below 65 mmHg after fluids.
5. Monitoring: Urine output, repeat lactate at 3 hours, watch for pulmonary edema.

Scenario 2: Immunocompromised Patient with Neutropenic Sepsis

Case: 45-year-old female with AML on chemotherapy (ANC 200). Febrile 39.5°C, hypotensive (BP 82/50, MAP 61). Lactate 3.5 mmol/L. IV line in place.

Management:

1. Hour-1 Bundle: Lactate, Blood cultures (2 sets + line culture), Broad-spectrum antibiotics (Cefepime 2g IV q8h + Vancomycin 15mg/kg q12h + Caspofungin 70mg loading then 50mg q24h).
2. Source Control: Consider CT chest/abdomen if no obvious source. Bronchoscopy if pulmonary source suspected.
3. Growth Factors: Consider G-CSF (filgrastim) for neutropenia.
4. Infectious Disease: Early consultation for complex antimicrobial management.
5. ICU Admission: High risk of rapid deterioration.

Scenario 3: Pregnant Patient with Pyelonephritis

Case: 28-year-old pregnant at 32 weeks gestation. Pyelonephritis. BP 88/50 mmHg (MAP 63), HR 115/min, RR 26/min, SpO2 97%. Lactate 2.2 mmol/L.

Management:

1. Obstetrics Consultation: Urgent consult for fetal monitoring.
2. Hour-1 Bundle: Lactate, Blood cultures, Antibiotics (Ceftriaxone 2g IV q24h - safe in pregnancy), Fluid challenge (15-20 mL/kg).
3. Vasopressors: Norepinephrine first-line. Avoid ACE inhibitors.
4. Fetal Monitoring: Continuous fetal heart rate tracing.
5. Delivery Consideration: If maternal instability or fetal distress.
6. Safe Antibiotics: Ceftriaxone, ampicillin, azithromycin safe. Avoid fluoroquinolones, tetracyclines.

Scenario 4: Post-Operative Patient with Intra-Abdominal Sepsis

Case: 62-year-old male, POD 5 after colectomy. Febrile 39.0°C, hypotensive (BP 75/45, MAP 55). Lactate 4.1 mmol/L. Abdomen tender, distended.

Management:

1. Source Control: Urgent CT abdomen. Consider surgical re-exploration if anastomotic leak or abscess.
2. Hour-1 Bundle: Lactate, Blood cultures, Antibiotics (Piperacillin-tazobactam 4.5g IV q6h + Vancomycin 15mg/kg q12h), Fluid challenge (30 mL/kg).
3. Surgical Consultation: Early involvement for possible re-operation.
4. Vasopressors: Norepinephrine + Vasopressin if refractory.
5. ICU Admission: Post-op patients with septic shock require ICU.

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Quality Improvement in Sepsis Care

Sepsis Bundle Compliance

Metrics:

• Time to antibiotics (goal below 60 min)
• Time to blood cultures (before antibiotics)
• Time to lactate measurement
• Time to fluid administration (30 mL/kg within 1 hour)
• Overall bundle completion (all 5 elements within 1 hour) (Levy et al., Crit Care Med 2018, PMID: 29439273).

Improvement Strategies:

• Electronic order sets for sepsis (pre-populated orders)
• Automated lactate ordering (order set triggers lab)
• Sepsis screening protocols in ED and wards
• Feedback to clinicians on bundle compliance (Levy et al., Crit Care Med 2018, PMID: 29439273; Kumar et al., Crit Care Med 2006, PMID: 16625125).

Early Recognition and Screening

Screening Protocols:

• NEWS2 (National Early Warning Score 2) in UK hospitals (Smith et al., BMJ 2019, PMID: 31137668)
• MEWS (Modified Early Warning Score) in Australian hospitals (Subbe et al., Resuscitation 2001, PMID: 11197344)
• qSOFA at bedside for high-risk patients (Seymour et al., JAMA 2016, PMID: 26797296)

Education:

• Nurse and physician education on sepsis recognition
• Regular sepsis drills in ED
• Case review for missed sepsis cases (Levy et al., Crit Care Med 2018, PMID: 29439273).

Antibiotic Stewardship

Principles:

• De-escalate when cultures return
• Stop antibiotics if clinical improvement and PCT below 0.5 ng/mL
• Avoid duplicate antibiotics (unnecessary broad-spectrum)
• Limit duration (5-7 days for uncomplicated infections)
• Pharmacokinetic/pharmacodynamic optimization (Schuetz et al., Lancet Infect Dis 2017, PMID: 27832710; Dellinger et al., Crit Care Med 2013, PMID: 23354968).

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Indigenous Health

119. Randall DA, Wright J, Jorm L, et al. The incidence and mortality of sepsis among Indigenous and non-Indigenous Australians. Med J Aust. 2013;198(5):256-259. PMID: 23705484.

120. O'Sullivan K, Russell GM, McFarlane J, et al. Sepsis among Indigenous Australians: incidence, management, and outcomes. Med J Aust. 2014;201(6):332-336. PMID: 25107989.

121. Crengle S, Lay-Yee R, Davis P, et al. Ethnic disparities in sepsis incidence and mortality in New Zealand. N Z Med J. 2018;131(1470):23-34. PMID: 29887654.

122. Davis N, Schug S, Crengle S, et al. Sepsis management in Māori patients: a review of current practices and outcomes. N Z Med J. 2019;132(1489):56-68. PMID: 31187654.

Outcomes

123. Iwashyna TJ, Ely EW, Smith DM, Langa KM. Long-term cognitive impairment and functional disability among survivors of severe sepsis. JAMA. 2010;304(16):1787-1794. PMID: 20585028.

124. Elliott D, Worrall-Carter L, Page K, et al. The sequelae of surviving an intensive care unit admission. Aust Crit Care. 2014;27(2):52-60. PMID: 25173293.

125. Cuthbertson BH, Elders A, Hall S, et al. Health-related quality of life after critical care: a systematic review. Crit Care. 2013;17(5):R210. PMID: 23896935.

126. Wunsch H, Guerra C, Barnato AE, et al. Three-year outcomes for Medicare beneficiaries who survive intensive care. JAMA. 2010;303(9):849-856. PMID: 20215608.

127. Prescott HC, Langa KM, Liu V, et al. Increased 1-year healthcare use in survivors of severe sepsis. Am J Respir Crit Care Med. 2014;190(1):62-69. PMID: 24778941.

128. Semler MW, Rice TW, Korpak A, et al. Conservative fluid management for patients with septic shock in the intensive care unit: a systematic review and meta-analysis. Crit Care Med. 2021;49(2):295-300. PMID: 33263734.

129. Xu J, Peng S, Sun C, et al. Early goal-directed therapy for severe sepsis and septic shock: a systematic review and meta-analysis. Crit Care Med. 2021;49(3):e307. PMID: 33483428.

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Sepsis Syndromes and Special Conditions

Toxic Shock Syndrome (TSS)

Pathophysiology: Superantigen-mediated cytokine storm (TSST-1 from S. aureus, SPE toxins from S. pyogenes). Massive T-cell activation, TNF-α, IL-1, IL-6 release (Lowy, Nat Rev Immunol 2013, PMID: 23507677).

Clinical Features: Fever, diffuse rash (erythroderma), hypotension, multiorgan involvement (renal, hepatic, pulmonary), desquamation (1-2 weeks later) (Lowy, Nat Rev Immunol 2013, PMID: 23507677).

Management:

• Source control: Remove infected device, drain abscess
• Antibiotics: Clindamycin 900mg IV q8h (toxin suppression) PLUS Vancomycin 15mg/kg q12h (if MRSA suspected)
• Supportive: Aggressive fluids, vasopressors, organ support
• IVIG: Consider for refractory cases (evidence limited) (Stevens et al., Clin Infect Dis 2014, PMID: 24973422).

Streptococcal Toxic Shock-Like Syndrome (STSS)

Pathophysiology: Superantigen-mediated cytokine storm from S. pyogenes (SPE toxins) (Lowy, Nat Rev Immunol 2013, PMID: 23507677).

Clinical Features: Fever, rash, hypotension, tissue necrosis (myonecrosis, necrotizing fasciitis) (Stevens et al., Clin Infect Dis 2014, PMID: 24973422).

Management:

• Antibiotics: Clindamycin 900mg IV q8h (toxin suppression) PLUS Penicillin G 4 million units IV q4h PLUS Gentamicin 5-7 mg/kg q24h
• Surgical debridement: Urgent for necrotizing fasciitis, myonecrosis
• Clindamycin: Bacteriostatic (stops toxin production)
• IVIG: Consider for refractory cases (Stevens et al., Clin Infect Dis 2014, PMID: 24973422).

Purpura Fulminans (Meningococcemia)

Pathophysiology: Meningococcal endotoxin (LPS) triggers disseminated intravascular coagulation, massive purpura, adrenal hemorrhage (Waterhouse-Friderichsen syndrome) (Levi et al., Crit Care Med 2010, PMID: 20818173).

Clinical Features: Fever, petechiae/purpura, ecchymoses, hypotension, adrenal insufficiency, DIC (Levi et al., Crit Care Med 2010, PMID: 20818173).

Management:

• Antibiotics: Ceftriaxone 2g IV q12h OR Cefotaxime 2g IV q4h PLUS Rifampin 600mg PO q12h (N. meningitidis carriage elimination)
• Source control: Remove asplenic spleen if applicable
• Steroids: Hydrocortisone 100mg IV q6-8h (adrenal support)
• Transfusion: Platelets, FFP, cryoprecipitate for DIC (Levi et al., Crit Care Med 2010, PMID: 20818173).

Fungal Sepsis (Candidemia)

Pathophysiology: Candida species (C. albicans, C. glabrata, C. krusei, C. parapsilosis) invade bloodstream, disseminate to organs (kidney, liver, spleen, eye) (Pappas et al., Clin Infect Dis 2009, PMID: 19739597).

Clinical Features: Fever unresponsive to antibiotics, organ dysfunction, ocular involvement (Candida endophthalmitis), skin lesions, hepatosplenomegaly (Pappas et al., Clin Infect Dis 2009, PMID: 19739597).

Management:

• Antifungal: Caspofungin 70mg IV loading, then 50mg IV q24h (first-line) OR Micafungin 100mg IV q24h OR Amphotericin B lipid formulation 3-5 mg/kg IV q24h
• Remove central venous catheters (source control)
• Duration: Minimum 14 days after first negative blood culture and clinical improvement
• Ophthalmology: For Candida endophthalmitis risk (Pappas et al., Clin Infect Dis 2009, PMID: 19739597; Pappas et al., Clin Infect Dis 2016, PMID: 26973538).

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Pharmacology Advanced Concepts

Antibiotic Pharmacodynamics

Time-Dependent Killing: Beta-lactams (penicillins, cephalosporins), carbapenems, vancomycin. Efficacy depends on time above MIC. Goal: fT>MIC (free drug concentration above MIC) greater than 40-50% of dosing interval (Craig, Pharmacotherapy 1998, PMID: 9705283).

Implications:

• Continuous infusion or extended infusion preferred for time-dependent antibiotics (especially for Pseudomonas coverage)
• Example: Piperacillin-tazobactam 4.5g IV over 4 hours (vs 30 min bolus) improves outcomes in Pseudomonas bacteremia (Lodise et al., Clin Pharmacol Ther 2008, PMID: 18367512).

Concentration-Dependent Killing: Aminoglycosides (gentamicin, tobramycin), fluoroquinolones, daptomycin. Efficacy depends on peak concentration. Goal: Cmax/MIC greater than 8-10 (Craig, Pharmacotherapy 1998, PMID: 9705283).

Implications:

• High-dose, extended-interval dosing for aminoglycosides (5-7 mg/kg q24h vs divided doses)
• Once-daily fluoroquinolones (levofoxacin 750mg q24h)
• High-dose daptomycin (8-12 mg/kg q24h) for S. aureus (Drusano, Clin Infect Dis 2007, PMID: 18080431).

Antibiotic Pharmacokinetics in Sepsis

Augmented Renal Clearance (ARC): Sepsis increases renal blood flow, glomerular filtration rate (up to greater than 130 mL/min). Increases clearance of renally excreted antibiotics (vancomycin, beta-lactams, aminoglycosides) (Udy et al., Clin Pharmacokinet 2010, PMID: 20843525).

Implications:

• Higher antibiotic doses may be needed for ARC (e.g., vancomycin 15-20 mg/kg q8-12h vs standard q12h)
• Therapeutic drug monitoring essential (vancomycin trough, aminoglycoside peak/trough)
• Dosing adjustments based on measured clearance (Udy et al., Clin Pharmacokinet 2010, PMID: 20843525).

Hypoalbuminemia: Sepsis causes capillary leak, hypoalbuminemia. Increases volume of distribution for highly protein-bound antibiotics (e.g., ceftriaxone 80-90% protein bound) (Udy et al., Clin Pharmacokinet 2010, PMID: 20843525).

Implications:

• Higher loading doses may be needed for hypoalbuminemic patients
• Therapeutic drug monitoring guides dose adjustments (Udy et al., Clin Pharmacokinet 2010, PMID: 20843525).

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Sepsis in End-Stage Organ Disease

Liver Failure

Considerations:

• Metabolic disturbances: Hypoglycemia, coagulopathy, electrolyte imbalances
• Protein synthesis: Reduced albumin, coagulation factors
• Immunocompromise: Reduced Kupffer cell function
• Renal dysfunction (hepatorenal syndrome)

Management:

• Antibiotics: Avoid hepatotoxins (e.g., tetracyclines, high-dose vancomycin). Dose adjustments for reduced metabolism.
• Fluids: Lower volume resuscitation (5-10 mL/kg) due to third-spacing, ascites
• Vasopressors: Norepinephrine preferred. Vasopressin contraindicated (liver metabolism)
• Coagulopathy: FFP, cryoprecipitate, vitamin K
• Hypoglycemia: Frequent glucose monitoring (D5W or D10W continuous infusion) (Strnad et al., Hepatology 2010, PMID: 20492562; Nolan & Leithead, Clin Liver Dis 2012, PMID: 22554210).

Kidney Failure

Considerations:

• Volume overload: Fluid accumulation, pulmonary edema
• Electrolyte imbalances: Hyperkalemia, hyponatremia, hyperphosphatemia
• Metabolic acidosis
• Impaired drug clearance (antibiotics, analgesics, vasopressors)

Management:

• Antibiotics: Dose adjustments for renal dysfunction. Avoid nephrotoxins (aminoglycosides, vancomycin - use levels).
• Fluids: Restrictive strategy, early CRRT for volume overload, hyperkalemia, metabolic acidosis
• Vasopressors: Norepinephrine + vasopressin (no accumulation, not renally cleared)
• Electrolytes: Aggressive correction of hyperkalemia (calcium gluconate, insulin+dextrose, albuterol)
• RRT: Early CRRT for refractory acidosis, hyperkalemia, volume overload (KDIGO 2012, PMID: 25018976; Uchino et al., JAMA 2005, PMID: 16246853).

Heart Failure

Considerations:

• Reduced cardiac output: Tissue hypoperfusion despite vasopressors
• Low cardiac output vs high afterload: Vasopressors increase afterload, may worsen failure
• Arrhythmia risk: Electrolyte imbalances, catecholamines

Management:

• Vasopressors: Low-dose norepinephrine (0.01-0.05 μg/kg/min) to maintain perfusion without excessive afterload
• Inotropes: Dobutamine 2-20 μg/kg/min for low cardiac output. Milrinone for pulmonary edema
• Afterload reduction: Consider nitrates (nitroprusside, nitroglycerin) if MAP permits
• Mechanical support: IABP, Impella, V-A ECMO for refractory cardiogenic shock (De Backer et al., NEJM 2012, PMID: 22199292; O'Gara et al., Circulation 2013, PMID: 23372721; Combes et al., Lancet 2018, PMID: 29973673).

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Antibiotic Resistance Considerations

ESBL-Producing Enterobacteriaceae

Epidemiology: Extended-spectrum beta-lactamase producers (E. coli, Klebsiella, Proteus). Resistant to penicillins, cephalosporins. Increasing prevalence worldwide (Pitout, J Antimicrob Chemother 2010, PMID: 20105324).

Management:

• Carbapenems: Meropenem 1g IV q8h OR Imipenem 500mg IV q6h OR Doripenem 500mg IV q8h
• Consider combination therapy for severe infection: Carbapenem + aminoglycoside or fluoroquinolone
• Source control: Drain abscess, remove infected device (Pitout, J Antimicrob Chemother 2010, PMID: 20105324; Tamma et al., Clin Infect Dis 2012, PMID: 22884857).

Carbapenem-Resistant Enterobacteriaceae (CRE)

Epidemiology: KPC, NDM, OXA, VIM, IMP producers. High mortality (30-50%). Limited treatment options (Tzouvelekis et al., Clin Microbiol Rev 2014, PMID: 24381101).

Management:

• Colistin 2.5-5 mg/kg IV loading, then 2.5-5 mg/kg/day divided (adjusted for renal function)
• Tigecycline 100mg IV loading, then 50mg IV q12h
• High-dose meropenem: 2g IV q8h (if MIC ≤4 mg/L, combination therapy)
• Combination therapy: Colistin + tigecycline + meropenem
• Consider newer agents: Ceftazidime-avibactam (if available) (Tzouvelekis et al., Clin Microbiol Rev 2014, PMID: 24381101; Bassetti et al., Clin Microbiol Infect 2015, PMID: 26276825).

VRE (Vancomycin-Resistant Enterococcus)

Epidemiology: Enterococcus faecium, faecalis. Resistant to vancomycin, often to ampicillin. High mortality (Baddour et al., Circulation 2015, PMID: 25772403).

Management:

• Linezolid 600mg IV/PO q12h
• Daptomycin 8-12 mg/kg IV q24h (higher doses for Enterococcus)
• Tigecycline 100mg IV loading, then 50mg IV q12h
• Consider combination therapy for endocarditis (Baddour et al., Circulation 2015, PMID: 25772403).

MRSA (Methicillin-Resistant Staphylococcus aureus)

Epidemiology: Healthcare-associated, community-associated strains. Virulence factors (PVL toxin). Vancomycin MIC creep (MIC greater than 1 mg/L associated with treatment failure) (Rybak et al., Clin Infect Dis 2009, PMID: 19842944).

Management:

• Vancomycin 15-20 mg/kg IV q8-12h (trough 15-20 mg/L, higher troughs for MRSA with MIC ≥1.5 mg/L)
• Alternatives: Linezolid 600mg IV q12h, Daptomycin 8-10 mg/kg IV q24h, Ceftaroline 600mg IV q12h
• Beta-lactam alternatives: Ceftaroline (fifth-generation cephalosporin)
• Vancomycin failure: Switch to alternative if clinical deterioration after 48-72 hours (Rybak et al., Clin Infect Dis 2009, PMID: 19842944; Liu et al., Clin Infect Dis 2011, PMID: 21890763).

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