Post-Cardiac Surgery ICU Management

Quick Answer

Post-cardiac surgery ICU management requires a structured, multidisciplinary approach addressing the unique physiological derangements following cardiopulmonary bypass (CPB). Mortality ranges from 1-3% for elective CABG to 10-20% for complex valve/combined procedures.

Immediate Priorities (First 4 Hours):

1. Structured handover using SBAR format (PMID: 21255531)
2. Haemodynamic stabilisation: MAP greater than 65 mmHg, CI greater than 2.2 L/min/m2
3. Bleeding assessment: Acceptable less than 200 mL/hr; action if greater than 400 mL in first hour
4. Temperature management: Rewarm to 36.5-37°C
5. Rhythm management: Optimise pacing, treat arrhythmias

Key Complications:

• Low Cardiac Output Syndrome (LCOS): CI less than 2.2 L/min/m2 with adequate preload; 5-10% incidence; mortality 10-40%
• Vasoplegia: SVR less than 800 dyn.s.cm-5 despite vasopressors; 5-25% incidence
• Cardiac Tamponade: Life-threatening; requires emergency resternotomy
• Postoperative AF (POAF): 25-50% incidence; peak day 2-3
• CSA-AKI: 20-40% incidence; need for RRT 2-5%
• Stroke: 1-5% incidence; higher with complex/redo surgery

Evidence-Based Targets:

• Restrictive transfusion (Hb trigger less than 75 g/L) - TRICS III (PMID: 29130845)
• Early extubation less than 6 hours (Fast-track ERAS protocol) - (PMID: 31054241)
• Beta-blockers for POAF prevention (70% risk reduction) - (PMID: 23395017)

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CICM Exam Focus

Written Exam (SAQ)

Common SAQ Stems:

• "A 68-year-old diabetic patient is admitted to ICU following CABG x3. Outline your immediate assessment and management."
• "Describe the recognition and management of low cardiac output syndrome following cardiac surgery."
• "A patient 4 hours post-aortic valve replacement develops sudden hypotension and rising CVP. Discuss your approach."
• "Outline the indications for re-exploration and emergency resternotomy in the post-cardiac surgery patient."
• "Discuss the prevention and management of postoperative atrial fibrillation following cardiac surgery."

Expected Depth:

• Structured handover checklist and initial assessment
• Haemodynamic targets and monitoring (CI, SVR, lactate)
• Inotrope and vasopressor selection (evidence-based)
• Bleeding thresholds and coagulation management (TEG/ROTEM)
• Tamponade recognition and resternotomy indications
• POAF prevention (beta-blockers, amiodarone) and management
• LCOS diagnostic criteria and escalation pathway
• Vasoplegia definition and methylene blue use
• CSA-AKI prevention and RRT timing
• ERAS/Fast-track protocols and early extubation criteria

Viva Voce

Expected Discussion Areas:

• Pathophysiology of LCOS and vasoplegia
• Inotrope pharmacology and selection
• Bleeding management algorithm
• Cardiac tamponade physiology and management
• ECMO/VAD indications in post-cardiotomy shock
• Neurological complications and prognostication
• Sternal wound infection and mediastinitis
• Quality improvement in cardiac surgery (ANZSCTS data)

Examiner Expectations:

• Safe, systematic approach to deteriorating patient
• Knowledge of current guidelines (ERAS, STS, EACTS)
• Evidence-based decision-making with trial citations
• Escalation criteria and when to involve surgical team
• Indigenous health awareness (cultural considerations in high-risk surgery)

Hot Case

Typical Presentations:

• Day 1 post-CABG with low cardiac output requiring inotropic support
• Post-aortic valve replacement with new complete heart block and temporary pacing
• Post-cardiac surgery bleeding with evolving coagulopathy
• Suspected cardiac tamponade with haemodynamic instability
• Post-cardiotomy cardiogenic shock on VA-ECMO
• POAF with rapid ventricular response requiring management
• Post-cardiac surgery respiratory failure requiring prolonged ventilation

Common Mistakes

1. Failing to perform structured handover - critical information missed
2. Over-reliance on CVP for fluid assessment (use dynamic parameters, echo)
3. Delay in recognising tamponade - waiting for classic signs that may not occur
4. Not considering surgical bleeding when coagulopathy corrected
5. Excessive fluid administration - dilutional coagulopathy, tissue oedema
6. Delay in re-exploration decision - increased mortality with delayed intervention
7. Failure to restart beta-blockers for POAF prevention
8. Not recognising vasoplegia distinct from low cardiac output
9. Missing graft occlusion (new ECG changes, RWMA on echo)
10. Inadequate neurological assessment on awakening

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Key Points

Must-Know Facts

1. Structured Handover Essential: Theatre-to-ICU handover using SBAR format reduces technical errors by 40% and improves information retention. "Sterile cockpit" approach - no verbal report until patient physiologically stable on ICU equipment (PMID: 21255531, 28830460)

2. Low Cardiac Output Syndrome (LCOS) Definition: CI less than 2.2 L/min/m2 with adequate preload (PCWP 15-18 mmHg or CVP 8-12 mmHg in normal ventricle); 5-10% incidence; mortality 10-40% if untreated (PMID: 28392182)

3. Vasoplegia Definition: SVR less than 800 dyn.s.cm-5 (or MAP less than 65 mmHg despite noradrenaline greater than 0.2 mcg/kg/min) with preserved or high cardiac output; distinct from LCOS; methylene blue is rescue therapy (PMID: 32522250)

4. Cardiac Tamponade Post-Surgery: May present atypically (loculated clot compressing single chamber); classic Beck's triad rare; sudden cessation of chest drain output + hypotension = tamponade until proven otherwise; emergency resternotomy required

5. Bleeding Thresholds for Re-Exploration: Greater than 400 mL in first hour, greater than 300 mL/hr for 2 hours, or greater than 200 mL/hr for 3 consecutive hours; sudden cessation of drainage concerning for tamponade (PMID: 28122234)

6. POAF Prevention: Beta-blockers reduce POAF by 70% (first-line); amiodarone reduces by 50% (alternative/adjunct); peak incidence day 2-3 post-surgery; 25-50% overall incidence (PMID: 23395017, 15306214)

7. Restrictive Transfusion Strategy: TRICS III confirmed non-inferiority of restrictive (Hb less than 75 g/L trigger) vs liberal strategy in cardiac surgery; reduces transfusion requirements without increasing mortality (PMID: 29130845)

8. CSA-AKI Incidence: 20-40% develop KDIGO Stage 1-3 AKI; 2-5% require RRT; associated with increased short and long-term mortality; avoid nephrotoxins, optimise haemodynamics (PMID: 25618754)

9. Fast-Track Extubation: ERAS guidelines recommend extubation within 6 hours for stable patients; reduces ICU LOS; criteria include stable haemodynamics, minimal bleeding, normothermia, adequate neurological function (PMID: 31054241)

10. Post-Cardiotomy ECMO Survival: VA-ECMO for refractory shock has 30-40% survival to discharge; 55-65% successfully weaned; pre-ECMO lactate, age, and organ failure predict outcomes (PMID: 31932135, 36326262)

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Immediate Postoperative Care

Theatre-to-ICU Handover

The transition from operating theatre to ICU is a high-risk period where critical information can be lost. Structured handover protocols significantly reduce errors and improve outcomes (PMID: 21255531, 17478648).

"Hands-Off" Stabilisation Phase

Before verbal handover, focus on physical stabilisation:

1. Transfer to ICU monitors - arterial line, ECG, SpO2, CVP
2. Connect to ICU ventilator - confirm ETT position, bilateral breath sounds
3. Verify all infusions - inotropes, vasopressors, sedation running
4. Connect chest drains to suction - note initial output
5. Confirm pacing - capture, rate, mode (if pacing wires in situ)
6. Check temperature - plan for rewarming
7. Patient physiologically STABLE before verbal handover begins

SBAR Structured Handover Format

S - Situation:

• Patient identification, age, weight
• Procedure performed (CABG, valve repair/replacement, combined)
• Current clinical status (stable/unstable)

B - Background:

• Pre-operative ejection fraction and ventricular function
• Significant comorbidities (diabetes, CKD, COPD, previous stroke)
• Pre-operative medications (especially anticoagulants, beta-blockers)
• Reason for surgery (elective vs urgent/emergent)

A - Assessment:

Surgical Details:

• CPB (bypass) time and cross-clamp time
• Ease of weaning from bypass
• Graft conduits used (LIMA, saphenous vein, radial artery)
• Valve prosthesis type and size (if applicable)
• Surgical complications (bleeding points, difficult cannulation)

Anaesthetic/Haemodynamic:

• Total fluid balance (crystalloid, colloid, blood products)
• Intra-operative urine output
• Most recent ABG (pH, lactate, K+, glucose, Hb)
• TEE findings (post-repair assessment, ventricular function)
• Current inotropes/vasopressors and doses

Lines and Access:

• Arterial line location
• Central line (CVC, PA catheter) location
• Chest drains (number, location, type)
• Epicardial pacing wires (atrial, ventricular, or both)

R - Recommendation:

• Haemodynamic targets (MAP, HR, CI if PAC in situ)
• Ventilation plan (weaning vs keep sedated)
• Bleeding management plan (ACT target, PEEP)
• Pacing settings (rate, mode, output)
• Anticipated problems (risk of vasoplegia, arrhythmia, re-exploration)

Initial ICU Checklist

IMMEDIATE (First 30 minutes):
□ Confirm ETT position (chest X-ray if not done)
□ Verify chest drain patency - strip/milk if indicated
□ Check all infusions connected and running
□ Measure chest drain output - document
□ Arterial blood gas - assess oxygenation, ventilation, metabolic status
□ 12-lead ECG - compare to pre-operative, assess for ischaemia
□ Check temperature - initiate rewarming protocol if hypothermic
□ Confirm pacing capture if epicardial wires present
□ Document neurological status - pupils, sedation level
□ Urine output - document, insert catheter if not present

WITHIN 1 HOUR:
□ Bedside echocardiography - assess ventricular function, exclude tamponade
□ Full blood count, coagulation studies (PT, APTT, fibrinogen)
□ Point-of-care testing (TEG/ROTEM) if available
□ Electrolytes, renal function, lactate
□ Chest X-ray - lines, tubes, pneumothorax, pulmonary oedema
□ Calculate cardiac index if PA catheter present
□ Assess for bleeding - calculate hourly loss
□ Optimise temperature - active warming if less than 36°C
□ Plan for sedation wean and extubation assessment

Initial Investigations

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Haemodynamic Management

Haemodynamic Targets

Evidence-based targets for post-cardiac surgery patients:

Monitoring Levels

Level 1 - Standard Monitoring (All patients):

• Continuous ECG with ST-segment monitoring
• Invasive arterial blood pressure
• Central venous pressure
• Pulse oximetry
• Temperature (core and peripheral)
• Urine output
• Chest drain output

Level 2 - Enhanced Monitoring (Unable to wean CPB, LCOS, complex surgery):

• Pulmonary artery catheter (CI, PCWP, SvO2)
• Continuous cardiac output monitoring
• ScvO2 or SvO2 trending

Level 3 - Complex/Unstable (Refractory shock, suspected complication):

• Transoesophageal echocardiography (TOE)
• Consider advanced cardiac output monitoring (PiCCO, FloTrac)
• Cerebral oximetry (high-risk neurological patients)

Fluid Management

Goal-directed fluid therapy using dynamic parameters rather than static pressures:

Dynamic Fluid Responsiveness Indicators:

• Stroke volume variation (SVV) greater than 12%
• Pulse pressure variation (PPV) greater than 13%
• Passive leg raise test (PLR) - CI increase greater than 10%
• Echocardiographic assessment (IVC variability, LV volume)

Fluid Considerations:

• Initial resuscitation: Balanced crystalloid (Hartmann's, Plasmalyte)
• Avoid excessive fluid loading - risk of dilutional coagulopathy, tissue oedema
• Colloids: Albumin if significant hypoalbuminaemia; avoid HES (CHEST trial)
• Blood products as indicated by bleeding and transfusion thresholds

Post-CPB Fluid Shifts:

• CPB causes systemic inflammatory response with capillary leak
• Third-spacing in first 24-48 hours
• Diuretic phase typically days 2-4
• Aim for net negative fluid balance by day 2-3 in stable patients

Inotropes and Vasopressors

First-Line Agents

For Low Cardiac Output (CI less than 2.2 L/min/m2):

For Vasoplegia (Low SVR with adequate/high CO):

Inotrope Selection Algorithm

LOW CARDIAC OUTPUT SYNDROME (CI < 2.2 L/min/m2)
                    |
                    v
    Optimise Preload (PCWP 12-18 mmHg)
                    |
                    v
    Confirm Adequate MAP (> 65 mmHg)
                    |
                    v
      +-------------+-------------+
      |             |             |
  LV Failure    RV Failure    Biventricular
      |             |             |
      v             v             v
 Dobutamine    Milrinone      Adrenaline
 2-10 mcg/kg  0.25-0.5 mcg   0.02-0.1 mcg
      |             |             |
      v             v             v
 Add norad    Consider iNO   Add norad if
 if hypot.    Avoid volume   hypotensive
              overload
      |             |             |
      v             v             v
 Escalate     Escalate       Consider
 adrenaline   adrenaline     IABP/Impella
                    |             |
                    v             v
               Consider MCS (ECMO/VAD)

Levosimendan

Levosimendan is a calcium sensitiser with vasodilatory properties:

• Mechanism: Increases troponin C calcium sensitivity + opens K-ATP channels
• Dose: 0.1 mcg/kg/min (loading dose often omitted due to hypotension)
• Duration: Effects persist 7-10 days (active metabolite OR-1896)
• Indications: Pre-existing low EF, difficult weaning from CPB, dobutamine-refractory LCOS
• Evidence: LEVO-CTS trial showed no mortality benefit vs placebo (PMID: 28388390)
• Australian availability: Special Access Scheme (not on PBS)

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Low Cardiac Output Syndrome (LCOS)

Definition and Diagnosis

Definition: Cardiac Index less than 2.2 L/min/m2 in the presence of adequate preload (PCWP 15-18 mmHg or CVP 8-12 mmHg) requiring inotropic support or mechanical circulatory support (PMID: 28392182).

Incidence: 5-10% of cardiac surgery patients; higher in:

• Pre-operative LV dysfunction (EF less than 40%)
• Emergency surgery
• Combined procedures (CABG + valve)
• Long CPB and cross-clamp times
• Redo surgery

Mortality: 10-40% depending on severity and response to treatment

Clinical Features

Haemodynamic:

• Hypotension (MAP less than 65 mmHg)
• Low pulse pressure
• Cold, mottled peripheries
• Prolonged capillary refill time
• Weak peripheral pulses

Metabolic:

• Rising lactate (greater than 2 mmol/L, or failure to clear)
• Metabolic acidosis
• Low SvO2 (less than 65%)

Organ Dysfunction:

• Oliguria (less than 0.5 mL/kg/hr)
• Altered mental state (if awake)
• Hepatic dysfunction (rising transaminases, bilirubin)

Aetiology

Management Algorithm

LCOS SUSPECTED (CI < 2.2, rising lactate, oliguria)
                    |
                    v
       EXCLUDE SURGICAL CAUSES
  - "Echo: Tamponade? Valve dysfunction? RWMA?"
  - "ECG: Ischaemia? Arrhythmia?"
  - Pace if bradycardic (rate 80-100)
                    |
                    v
       OPTIMISE PRELOAD
  - Fluid challenge if hypovolaemic (dynamic parameters)
  - Avoid overloading if RV failure/high PCWP
                    |
                    v
       START/OPTIMISE INOTROPE
  - Dobutamine 5-10 mcg/kg/min first-line
  - Add noradrenaline if hypotensive
  - Milrinone if RV failure/pulmonary hypertension
                    |
                    v
       INADEQUATE RESPONSE (CI still < 2.2)
  - Escalate inotrope (adrenaline up to 0.2 mcg/kg/min)
  - Consider IABP (limited evidence post-IABP-SHOCK II)
                    |
                    v
       REFRACTORY LCOS
  - Urgent surgical review
  - Consider VA-ECMO or Impella
  - Consider return to theatre (graft revision, etc.)

Echocardiographic Assessment

Bedside echo is essential in LCOS to:

1. Exclude tamponade - pericardial effusion, chamber collapse
2. Assess LV function - global vs regional dysfunction
3. Assess RV function - dilation, paradoxical septal motion
4. Valve function - new regurgitation, prosthetic malfunction
5. Volume status - LV end-diastolic area, IVC variability
6. Regional wall motion - suggests graft occlusion if new
7. Air embolism - bubbles in cardiac chambers (post-CPB)

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Bleeding and Coagulopathy

Post-CPB Coagulopathy Pathophysiology

Cardiopulmonary bypass induces a complex coagulopathy:

1. Haemodilution: Crystalloid prime dilutes clotting factors and platelets
2. Platelet dysfunction: Mechanical trauma, hypothermia, GPIIb/IIIa activation
3. Factor consumption: Activation of coagulation cascade
4. Fibrinolysis: CPB activates fibrinolytic system
5. Hypothermia: Impairs enzymatic coagulation reactions
6. Heparin effects: Residual heparin despite protamine reversal
7. Protamine excess: Can itself cause coagulopathy

Acceptable Drainage Rates

Universal Definition of Perioperative Bleeding (UDPB) (PMID: 24411601):

• Class 0: Insignificant - Less than 1 L total drainage in 12 hours
• Class 1: Mild - 1.0-1.5 L total drainage, no intervention needed
• Class 2: Moderate - 1.5-2.0 L drainage or requirement for transfusion
• Class 3: Severe - Greater than 2.0 L drainage or re-exploration
• Class 4: Massive - Transfusion greater than 10 units RBC

Point-of-Care Coagulation Testing

TEG (Thromboelastography) and ROTEM (Rotational Thromboelastometry) provide rapid, viscoelastic assessment of clot formation and lysis.

Advantages over traditional tests:

• Results in 10-15 minutes (vs 45-60 min for lab PT/APTT)
• Assess entire clotting cascade including fibrinolysis
• Guide targeted blood product administration
• Reduce unnecessary transfusion (PMID: 34921903)

Goal-Directed Transfusion Algorithm (ROTEM/TEG-Based):

Transfusion Thresholds

TRICS III Trial (PMID: 29130845): Restrictive strategy (Hb less than 75 g/L) non-inferior to liberal (Hb less than 95 g/L) in cardiac surgery.

Antifibrinolytics

Tranexamic Acid (TXA):

• Lysine analogue that inhibits plasminogen activation
• Standard dose: 1g loading then 1g over 8 hours (or 10 mg/kg loading + 1 mg/kg/hr)
• Reduces blood loss by 30% and transfusion requirements
• Class I recommendation in all cardiac surgery (PMID: 28939101)
• Caution: Seizure risk at high doses (greater than 100 mg/kg)

Indications for Re-Exploration

Surgical Re-Exploration Indicated:

1. Greater than 400 mL in first hour despite coagulopathy correction
2. Greater than 300 mL/hr for 2 consecutive hours
3. Greater than 200 mL/hr for 3 consecutive hours
4. Sudden massive bleeding (greater than 500 mL "gush")
5. Sudden cessation of drainage with haemodynamic instability (tamponade)
6. Clinical/echo evidence of cardiac tamponade
7. Persistent mediastinal bleeding despite optimised coagulation

Re-Exploration Rate: 3-5% of cardiac surgery patients Mortality with Re-Exploration: 2-3 times higher than uncomplicated surgery

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Cardiac Tamponade

Recognition

Post-operative cardiac tamponade is a life-threatening emergency requiring immediate recognition and intervention.

Key Differences from Medical Tamponade:

• Often loculated - clot may compress single chamber
• Classic Beck's triad (hypotension, muffled heart sounds, JVD) often absent
• May present as isolated RV or RA compression
• Equalisation of diastolic pressures may not occur

Clinical Features

Haemodynamic:

• Hypotension (may be sudden)
• Tachycardia
• Elevated CVP (may be masked by hypovolaemia)
• Pulsus paradoxus (greater than 10 mmHg drop in SBP with inspiration) - difficult to assess in ventilated patients
• Narrow pulse pressure
• Equalisation of diastolic pressures (CVP ≈ PADP ≈ PCWP)

Key Warning Signs:

• Sudden cessation of chest drain output with deterioration
• Rising CVP with falling MAP
• Increasing inotrope/vasopressor requirements
• Oliguria
• Acidosis/rising lactate

Diagnosis

Clinical diagnosis - do not delay for investigations if clinical picture clear

Echocardiography:

• Pericardial effusion/haematoma
• RA/RV collapse in diastole
• IVC plethora without respiratory variation
• "Swinging heart" may not be present (clotted blood)
• Loculated collection - may compress single chamber only
• Paradoxical septal motion

Chest X-Ray: May show widened mediastinum (limited sensitivity)

Important: Negative echo does not exclude tamponade if clot is loculated and not visible from subcostal/parasternal windows

Emergency Management

CARDIAC TAMPONADE SUSPECTED
            |
            v
    Immediate Actions:
    - Call for help (Cardiac surgeon, senior ICU)
    - 100% FiO2
    - Volume resuscitation (maintain preload)
    - Reduce/stop positive pressure ventilation if possible
    - Reduce PEEP to minimum safe level
    - Consider vasopressor support (temporary measure only)
            |
            v
    UNSTABLE / ARREST?
    /              \
  YES              NO
   |                |
   v                v
EMERGENCY        Urgent
RESTERNOTOMY     Theatre
(Bedside)        (Controlled)

Emergency Resternotomy

Indication: Cardiac arrest or peri-arrest within 10 days of cardiac surgery

Timing: Resternotomy should be performed within 5 minutes of cardiac arrest onset (PMID: 28122234)

Location: ICU bedside (cannot wait for theatre transfer)

Procedure Requirements:

• Emergency resternotomy kit at bedside (wire cutters, retractor, internal paddles)
• Full aseptic technique if time allows
• Internal cardiac massage until bleeding controlled and cardiac output restored
• Definitive surgical repair in operating theatre

Outcomes:

• Survival to discharge: 17-79% (varies widely with indication and timing)
• Better outcomes with earlier intervention
• Best outcomes when cause is reversible (tamponade, haemorrhage)

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Arrhythmias

Postoperative Atrial Fibrillation (POAF)

Incidence (PMID: 33115135):

• CABG alone: 20-30%
• Valve surgery alone: 30-40%
• Combined CABG + valve: Up to 50%
• Peak incidence: Day 2-3 post-operatively

Risk Factors:

• Advanced age
• Pre-existing atrial disease
• Withdrawal of beta-blockers
• Electrolyte abnormalities (hypokalaemia, hypomagnesaemia)
• Atrial ischaemia/inflammation
• Fluid overload
• Sympathetic activation

Consequences:

• Haemodynamic compromise
• Increased stroke risk
• Prolonged ICU and hospital stay
• Increased hospital costs

POAF Prevention

Beta-Blockers (Class I Recommendation) (PMID: 23395017, 31081308):

• 70% risk reduction for POAF
• Continue pre-operative beta-blocker; restart ASAP post-operatively
• If beta-blocker naive: Consider starting low-dose metoprolol
• Contraindications: Severe bradycardia, heart block, acute decompensated HF

Amiodarone (Class IIa Recommendation) (PMID: 15306214):

• 50% risk reduction for POAF
• Use when beta-blockers contraindicated or in high-risk patients
• Prophylactic dosing: 400-600 mg/day starting 1-7 days pre-op
• Post-operative: 200 mg TDS for 5-7 days

Combination Therapy (PMID: 15155100):

• Beta-blocker + amiodarone superior to either alone
• Consider for highest-risk patients (elderly, combined surgery, prior AF)

Magnesium Supplementation:

• Maintain Mg greater than 1.0 mmol/L
• Some evidence for prophylactic supplementation (less robust than beta-blockers)

Electrolyte Targets:

• K+ greater than 4.0 mmol/L
• Mg2+ greater than 1.0 mmol/L
• Ca2+ ionised 1.1-1.3 mmol/L

POAF Management

Haemodynamically Unstable (Hypotension, chest pain, pulmonary oedema):

• DC cardioversion 150-200 J biphasic (synchronized)
• May require repeat cardioversion
• Antiarrhythmic loading post-cardioversion

Haemodynamically Stable:

Anticoagulation:

• If AF persists greater than 48 hours, anticoagulation required before cardioversion
• Calculate CHA2DS2-VASc score
• Heparin infusion initially; transition to warfarin or DOAC
• Balance bleeding risk in immediate post-operative period

Cardioversion:

• Electrical: 150-200 J biphasic (synchronized)
• Pharmacological: Amiodarone (most common), flecainide (if no structural heart disease)

Epicardial Pacing Wires

Standard Placement: Atrial and ventricular wires placed during surgery

Indications for Temporary Pacing:

• Sinus bradycardia (less than 50 bpm with symptoms)
• Complete heart block (common after aortic valve surgery)
• Atrial pacing to prevent AF (controversial evidence)
• Overdrive pacing for atrial flutter

Standard Settings:

• Mode: DDD (dual chamber) or VVI (ventricular only)
• Rate: 80-100 bpm
• Output: 5-10 mA (2-3x threshold)
• Sensitivity: 2-3 mV (atrial), 5-6 mV (ventricular)

Wire Removal:

• Usually day 3-5 post-operatively
• Ensure INR less than 1.5 before removal
• Gentle steady traction
• Monitor for bleeding post-removal
• Rare but serious complication: Ventricular perforation/tamponade

Other Arrhythmias

Ventricular Arrhythmias:

• VT/VF: Consider ischaemia (graft occlusion), electrolyte abnormalities
• Treat reversible causes
• DC cardioversion if haemodynamically unstable
• Amiodarone for recurrent VT

Bradyarrhythmias:

• Complete heart block: More common post-aortic valve surgery
• Utilize epicardial pacing wires
• May require permanent pacemaker if persists greater than 7 days

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Respiratory Management

Initial Ventilator Settings

Extubation Criteria (Fast-Track Protocol)

ERAS Cardiac Surgery Guidelines recommend early extubation (less than 6 hours) for suitable patients (PMID: 31054241).

Extubation Criteria:

Fast-Track Benefits:

• Reduced ICU length of stay
• Reduced hospital length of stay
• Reduced respiratory complications
• Reduced costs
• No increase in mortality or re-intubation rates

Causes of Prolonged Ventilation

Definition: Mechanical ventilation greater than 24-48 hours post-surgery

Respiratory Complications

Atelectasis:

• Most common respiratory complication (60-90%)
• Left lower lobe most affected (retraction during surgery)
• Prevention: Early mobilization, incentive spirometry, adequate analgesia
• Treatment: Chest physiotherapy, CPAP, bronchoscopy if lobar collapse

Pleural Effusion:

• Very common (up to 50% by day 7)
• Usually reactive; larger if LIMA harvested
• Drain if symptomatic or causing respiratory compromise

Diaphragmatic Dysfunction:

• Phrenic nerve injury (especially with IMA harvest using topical cooling)
• Left more common than right
• Usually recovers over weeks to months
• May require prolonged ventilatory support

ARDS:

• Rare but serious (1-2%)
• Manage according to ARDSNet principles (PMID: 10793162)
• Consider transfusion-related acute lung injury (TRALI) if post-transfusion

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Neurological Complications

Stroke

Incidence: 1-5% overall; higher with:

• Complex/redo surgery
• Aortic surgery (highest risk)
• Pre-existing cerebrovascular disease
• Atrial fibrillation
• Advanced age

Types:

• Type 1 (Focal): Stroke with focal neurological deficit
• Type 2 (Diffuse): Encephalopathy, confusion, prolonged obtundation

Risk Factors:

• Aortic atheroma ("shaggy aorta")
• Carotid artery disease
• Previous stroke/TIA
• Atrial fibrillation (new or pre-existing)
• Age greater than 70
• Diabetes
• Prolonged CPB time
• Low cardiac output

Assessment:

• Neurological examination on awakening from sedation
• Delayed awakening is RED FLAG - investigate
• Pupillary responses, motor function (spontaneous or to command)
• If deficit detected: Urgent CT brain (rule out haemorrhage), consider CT angiography

Management:

• Maintain adequate cerebral perfusion (MAP greater than 65-80 mmHg)
• Avoid hyperglycaemia (target 8-10 mmol/L)
• Normothermia (avoid fever)
• Thrombolysis generally contraindicated post-cardiac surgery (bleeding risk)
• Neurology/Stroke team consultation
• Consider decompressive craniectomy for massive hemispheric stroke

Postoperative Delirium

Incidence: 25-50% of cardiac surgery patients (PMID: 35147493)

Risk Factors:

• Advanced age
• Pre-existing cognitive impairment
• Prolonged CPB time
• Transfusion
• Post-operative complications (infection, renal failure, hypoxia)
• Medications (benzodiazepines, anticholinergics, opioids)

Association with CSA-AKI (PMID: 35147493, 32773615):

• AKI is independent risk factor for delirium
• Mechanism: Uraemic toxins, inflammatory cytokines, metabolic derangements
• Kidney-brain axis increasingly recognized

Prevention (CAM-ICU screening):

• Minimize sedation (avoid benzodiazepines)
• Early mobilization
• Orientation strategies (clocks, windows, family)
• Correct metabolic derangements
• Adequate pain control
• Sleep hygiene

Management:

• Treat underlying causes
• Non-pharmacological interventions first
• Pharmacological: Haloperidol 0.5-2 mg IV PRN (caution with QTc prolongation)
• Quetiapine 12.5-50 mg BD for hyperactive delirium
• Dexmedetomidine for agitated delirium in ventilated patients

Postoperative Cognitive Dysfunction (POCD)

Definition: Decline in cognitive function persisting beyond the immediate postoperative period (weeks to months)

Incidence:

• 25-50% at hospital discharge
• 10-30% at 6 months
• 5-10% at 1 year (some studies suggest persistent deficits)

Risk Factors:

• Age
• Pre-existing cognitive impairment
• Perioperative stroke
• Prolonged CPB time
• Post-operative complications
• Genetic factors (APOE-ε4 allele)

Association with AKI (PMID: 37512214, 32454531):

• AKI accelerates cognitive decline
• Long-term MMSE scores lower in patients with perioperative AKI

Prevention:

• Optimal cerebral perfusion during surgery
• Avoid deep hypothermia
• Limit embolic load (epiaortic scanning)
• Post-operative cognitive rehabilitation

---

Renal Complications (CSA-AKI)

Definition and Epidemiology

Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI) using KDIGO criteria (PMID: 25618754):

Incidence:

• Any CSA-AKI: 20-40%
• Severe CSA-AKI (Stage 2-3): 5-15%
• CSA-AKI requiring RRT: 2-5%

Mortality Impact:

• CSA-AKI increases in-hospital mortality 3-8 fold
• Even Stage 1 AKI increases long-term mortality
• CSA-AKI with RRT: Mortality 40-60%

Risk Factors

Prevention Strategies

1. Preoperative Optimisation:

   • Avoid contrast 48-72 hours before surgery
   • Optimise volume status
   • Hold nephrotoxins (NSAIDs, aminoglycosides)
   • Consider delaying surgery if recent AKI

2. Intraoperative:

   • Adequate perfusion pressure during CPB (MAP greater than 60-70 mmHg)
   • Avoid excessive haemodilution
   • Minimise CPB time
   • Pulsatile flow (where available)

3. Postoperative:

   • Maintain adequate cardiac output and MAP
   • Avoid/minimise nephrotoxins
   • Early recognition and management of LCOS
   • Balanced fluid management
   • Avoid hyperglycaemia

RRT Indications

Absolute Indications:

• Refractory hyperkalaemia (K+ greater than 6.5 mmol/L despite treatment)
• Refractory metabolic acidosis (pH less than 7.1)
• Refractory volume overload (pulmonary oedema unresponsive to diuretics)
• Uraemic complications (encephalopathy, pericarditis, bleeding)

Relative Indications:

• Oliguria/anuria despite fluid optimisation
• Progressive azotaemia
• Severe electrolyte abnormalities
• Drug toxicity requiring removal

Modality: CVVHDF preferred in haemodynamically unstable patients

Timing: STARRT-AKI and IDEAL-ICU suggest no benefit to "early" RRT in non-emergent situations

---

Infection

Surgical Site Infection and Mediastinitis

Sternal Wound Infection (SWI) Classification:

• Superficial: Skin and subcutaneous tissue only
• Deep Sternal Wound Infection (DSWI)/Mediastinitis: Involves sternum and/or mediastinal structures

Incidence: 0.25-4% (higher in high-risk patients)

Mortality: DSWI/Mediastinitis: 10-40% (PMID: 30107936)

Risk Factors:

• Diabetes (especially poor glycaemic control)
• Obesity (BMI greater than 30)
• COPD
• Renal failure
• Bilateral IMA harvest (especially in diabetics)
• Prolonged surgery
• Re-exploration for bleeding
• Immunosuppression
• Staphylococcus aureus nasal carriage

Prevention

1. Preoperative Decolonisation (PMID: 19369326):

   • Mupirocin 2% nasal ointment BD for 5 days
   • Chlorhexidine 4% body wash
   • Screen for MRSA; contact precautions if positive

2. Antibiotic Prophylaxis (PMID: 27150242):

   • Cefazolin 2g IV (or vancomycin if penicillin allergy/MRSA colonised)
   • Administer within 60 minutes of incision
   • Repeat every 3-4 hours during surgery
   • Continue for 24-48 hours post-operatively only

3. Glycaemic Control (PMID: 28212674):

   • Target glucose less than 10 mmol/L (180 mg/dL)
   • Insulin infusion if needed
   • Avoid tight control (hypoglycaemia risk)

4. Surgical Technique:

   • Avoid BIMA in diabetics when possible
   • Meticulous haemostasis
   • Minimise electrocautery tissue damage

Diagnosis of Mediastinitis

Clinical Features:

• Fever persisting beyond day 3-5
• Sternal wound erythema, warmth, tenderness
• Purulent drainage from sternal wound
• "Sternal click" or instability (dehiscence)
• Failure to thrive, persistent organ dysfunction

Laboratory:

• Elevated WCC, CRP
• Procalcitonin (distinguishes systemic vs local infection)
• Blood cultures

Imaging (PMID: 22441097, 21669467):

• CT Chest: Gold standard
  • Retrosternal fluid collection
  • Gas bubbles in mediastinum
  • Sternal dehiscence
  • Bone destruction

Management of Mediastinitis

1. Antibiotic Therapy:

   • Broad-spectrum initially (vancomycin + piperacillin-tazobactam or meropenem)
   • Narrow based on cultures
   • Prolonged course (4-6 weeks typically)

2. Surgical Debridement:

   • Urgent surgical exploration
   • Removal of infected tissue, wires, and devitalised bone
   • Multiple debridements often required

3. Negative Pressure Wound Therapy (NPWT) (PMID: 23602005, 20434314):

   • VAC therapy now standard of care
   • Reduces mortality vs conventional dressings
   • Accelerates wound granulation
   • Bridge to definitive surgical closure
   • Caution: Risk of RV rupture - use protective interface layer (PMID: 21123473)

4. Definitive Closure:

   • Primary sternal closure (if bone viable)
   • Muscle flap reconstruction (pectoralis, rectus abdominis, omentum)

Infective Endocarditis

Post-operative endocarditis (prosthetic valve endocarditis - PVE):

• Early (less than 1 year): Usually S. aureus, coagulase-negative staphylococci
• Late (greater than 1 year): Similar to native valve (streptococci, enterococci)

Diagnosis: Duke criteria + TOE (TTE often insufficient for prosthetic valves)

Management: Prolonged IV antibiotics (6 weeks minimum) ± surgical intervention

---

Vasoplegia

Definition

Vasoplegic Syndrome (VS) is characterised by:

• Low SVR (less than 800 dyn.s.cm-5)
• Normal or elevated cardiac output (CI greater than 2.5 L/min/m2)
• Hypotension (MAP less than 65 mmHg) despite vasopressor therapy
• Absence of sepsis (PMID: 32522250)

Incidence: 5-25% of cardiac surgery patients

Risk Factors:

• Pre-operative ACE-I/ARB use (most important modifiable factor)
• Low pre-operative EF
• Prolonged CPB time (greater than 120 minutes)
• Pre-operative beta-blocker use
• Redo surgery
• Heart failure
• Obesity

Pathophysiology

CPB triggers a systemic inflammatory response:

1. Nitric Oxide (NO) Overproduction:

   • Inducible NOS (iNOS) upregulated
   • NO activates soluble guanylate cyclase (sGC)
   • Increased cGMP causes vascular smooth muscle relaxation

2. Vasopressin Deficiency:

   • Relative vasopressin deficiency post-CPB
   • Loss of V1 receptor-mediated vasoconstriction

3. Adrenal Insufficiency:

   • Critical illness-related corticosteroid insufficiency
   • Contributes to vasopressor resistance

Management

Step 1: First-Line Vasopressor

• Noradrenaline 0.05-1.0 mcg/kg/min
• Target MAP greater than 65 mmHg
• Titrate to response

Step 2: Second-Line Vasopressor

• Vasopressin 0.01-0.04 units/min (fixed dose range)
• Noradrenaline-sparing effect
• Particularly effective in ACE-I-induced vasoplegia
• Do not exceed 0.04 U/min

Step 3: Rescue Therapy

Methylene Blue (PMID: 15607433, 27103394, 28453140):

• Mechanism: Inhibits soluble guanylate cyclase, blocks cGMP production
• Dose: 1-2 mg/kg IV bolus over 10-20 minutes
• May repeat or continue infusion 0.25-0.5 mg/kg/hr
• Highly effective when administered early
• Response: Typically within 30-60 minutes

Contraindications to Methylene Blue:

• G6PD deficiency (haemolysis risk)
• Serotonergic medications (SSRIs, SNRIs, MAOIs) - risk of serotonin syndrome
• Pulmonary hypertension with RV failure (increases pulmonary resistance)

Cautions:

• Interferes with pulse oximetry (falsely low SpO2)
• Blue discolouration of skin and urine

Hydrocortisone:

• 100 mg IV q8h if suspected relative adrenal insufficiency
• Consider if vasopressor requirements remain high
• Evidence in cardiac surgery vasoplegia is limited

Angiotensin II (Giapreza):

• Emerging option for refractory distributive shock
• Dose: 5-40 ng/kg/min
• Limited availability in Australia/NZ

Vasoplegia Management Algorithm

VASOPLEGIA SUSPECTED
(Low SVR, normal/high CO, hypotension despite NA)
                    |
                    v
    Confirm with Echo/PAC: CI > 2.5, SVR < 800
    Rule out: Bleeding, tamponade, sepsis
                    |
                    v
    NORADRENALINE escalation (up to 0.3 mcg/kg/min)
                    |
                    v
    ADD VASOPRESSIN 0.03-0.04 U/min
                    |
                    v
    Still hypotensive?
    (NA > 0.3 + Vasopressin max dose)
                    |
                    v
    METHYLENE BLUE 1.5-2 mg/kg IV bolus
    (Check no G6PD deficiency or serotonergic drugs)
                    |
                    v
    Response?
    /        \
  YES         NO
   |           |
   v           v
  Wean      Consider:
  NA        - Hydrocortisone 100mg q8h
            - Repeat MB (infusion 0.5 mg/kg/hr)
            - Angiotensin II (if available)
            - Surgical causes (bleeding, tamponade)

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Fast-Track Protocols and Enhanced Recovery (ERAS)

ERAS Cardiac Surgery Principles

The Enhanced Recovery After Surgery (ERAS) Cardiac Society Guidelines (PMID: 31054241) provide evidence-based recommendations:

Fast-Track Cardiac Anaesthesia

Goals:

• Extubation within 6 hours of ICU arrival
• ICU discharge within 24 hours
• Hospital discharge within 5-7 days

Selection Criteria for Fast-Track:

• Elective, uncomplicated surgery
• Good pre-operative cardiac function (EF greater than 40%)
• No significant comorbidities
• Uncomplicated intra-operative course
• Minimal bleeding
• Stable haemodynamics (minimal inotropes)

Anaesthetic Modifications:

• Short-acting agents (propofol, remifentanil)
• Avoid long-acting muscle relaxants
• Regional techniques (paravertebral block, erector spinae plane block)
• Intraoperative opioid-sparing strategies

Early Extubation Protocol

Pre-Extubation Checklist:

Post-Extubation Care:

• High-flow nasal cannula or CPAP if needed
• Chest physiotherapy
• Early mobilization (sitting out of bed day 1)
• Oral intake when safe

Multimodal Analgesia

Opioid-Sparing Strategies:

• Paracetamol 1g IV/PO q6h (scheduled)
• NSAIDs (use with caution - renal/bleeding risk)
• Ketamine infusion (0.1-0.2 mg/kg/hr)
• Regional anaesthesia (paravertebral, erector spinae plane block)
• Dexmedetomidine (sedation + analgesia)

Benefits:

• Reduced opioid consumption
• Faster recovery of bowel function
• Earlier mobilization
• Reduced respiratory depression

---

ECMO and VAD in Post-Cardiotomy Shock

Post-Cardiotomy Cardiogenic Shock (PCCS)

Definition: Cardiogenic shock occurring after cardiac surgery, refractory to inotropic support and IABP.

Incidence: 0.5-1.5% of cardiac surgery patients

Indications for Mechanical Circulatory Support (MCS):

• Failure to wean from CPB despite inotropes
• Post-operative LCOS refractory to escalating inotropes
• Cardiac arrest in post-operative period
• CI less than 2.0 L/min/m2 with:
  • Rising lactate (greater than 5 mmol/L)
  • Oliguric/anuric renal failure
  • Mixed venous saturation less than 50%

VA-ECMO for PCCS

Survival Outcomes (PMID: 31932135, 33664052, 36326262):

• Successful weaning: 55-65%
• Survival to hospital discharge: 30-40%
• 1-year survival: 25-30%

Predictors of Poor Outcome:

• Advanced age (greater than 70-75 years)
• Pre-ECMO lactate greater than 6 mmol/L
• Pre-ECMO multi-organ failure
• Delayed initiation (rescue vs planned)
• Failure to decompress LV

Complications:

• Re-exploration for bleeding: 40-50%
• Acute kidney injury: 50-70%
• Stroke: 10-15%
• Limb ischaemia: 10-20%

LV Venting Strategies

Problem: VA-ECMO increases LV afterload, causing:

• LV distension
• Increased wall stress
• Impaired myocardial recovery
• Pulmonary oedema

Venting Options:

• Impella device (ECMELLA configuration) (PMID: 32861214)
• Surgical LV vent (via right superior pulmonary vein)
• Atrial septostomy
• IABP (limited venting capacity)

ECMELLA Evidence:

• Combining Impella with VA-ECMO may improve LV unloading
• Some data suggest improved survival and weaning rates
• Increases bleeding risk

IABP (Intra-Aortic Balloon Pump)

Mechanism:

• Diastolic augmentation: Inflates in diastole, increases coronary perfusion
• Systolic unloading: Deflates in systole, reduces afterload

Evidence in Cardiogenic Shock:

• IABP-SHOCK II: No mortality benefit in AMI cardiogenic shock (PMID: 23062528)
• Limited specific evidence for PCCS

Current Role:

• May still be used as first-line MCS in some centres
• Bridge to decision/recovery
• Contraindicated: Aortic regurgitation, aortic dissection

VAD (Ventricular Assist Device)

Short-Term VADs:

• Impella (2.5, CP, 5.0, 5.5)
• CentriMag
• TandemHeart

Indications in PCCS:

• Bridge to recovery
• Bridge to decision
• Bridge to transplant (rarely in PCCS)
• Destination therapy (chronic VAD - not typically for PCCS)

---

SAQ Practice Questions

SAQ 1: Low Cardiac Output Syndrome (15 marks)

Question: A 72-year-old male with diabetes and an ejection fraction of 35% is admitted to ICU following combined CABG x3 and aortic valve replacement. Four hours post-operatively, the nursing staff are concerned about the following parameters:

• MAP 55 mmHg (on noradrenaline 0.15 mcg/kg/min)
• HR 90 bpm (pacing at 80, sensing)
• CVP 14 mmHg
• Chest drain output 80 mL in last hour
• Urine output 15 mL in last 2 hours
• Lactate 4.2 mmol/L (was 2.8 mmol/L on arrival)
• Core temperature 35.8°C

a) List the differential diagnoses for this clinical picture. (3 marks)

b) Describe your immediate assessment of this patient. (4 marks)

c) Outline your management approach, including specific treatments and escalation criteria. (6 marks)

d) The patient's condition deteriorates further despite optimal medical management. When would you consider mechanical circulatory support and what are the options? (2 marks)

---

Model Answer:

a) Differential Diagnoses (3 marks)

b) Immediate Assessment (4 marks)

1. A - Airway: Confirm ETT position, ventilation adequate
2. B - Breathing: Assess oxygenation, ventilator parameters
3. C - Circulation:
   • Physical examination: Peripheral perfusion (cold/mottled?), JVP
   • Pacing: Check capture and sensing, underlying rhythm
   • Chest drains: Patent? Sudden reduction concerning for tamponade
   • ECG: New ST changes (graft occlusion?), pacing artefacts
4. Bedside Echocardiography:
   • CRITICAL - assess for tamponade (pericardial effusion, chamber collapse)
   • LV function (global vs regional dysfunction - RWMA suggests ischaemia)
   • RV function
   • Prosthetic valve function (gradients, regurgitation)
   • Volume status (LV cavity size, IVC)
5. Investigations:
   • ABG (oxygenation, acid-base, lactate trend, K+)
   • FBC, coagulation (assess for ongoing bleeding)
   • Calculate CI if PA catheter present

c) Management Approach (6 marks)

Immediate Interventions:

1. Temperature: Active rewarming to 37°C (Bair Hugger, warmed fluids) - hypothermia impairs contractility and coagulation
2. Optimise Preload: If echo shows low LV volume - cautious fluid bolus (250 mL crystalloid); if CVP 14 with full LV - avoid further fluid
3. Correct Metabolic: Correct acidosis (consider bicarbonate if pH less than 7.1), normalise K+ and Ca2+

Inotropic Support: 4. Add Inotrope:

• Dobutamine 5 mcg/kg/min - first-line for LV systolic dysfunction
• OR Milrinone 0.25-0.5 mcg/kg/min - if RV dysfunction/pulmonary hypertension
• Titrate to CI greater than 2.2 L/min/m2

5. Continue Noradrenaline: Maintain MAP greater than 65 mmHg

If Surgical Cause Suspected: 6. Urgent Surgical Review: If echo shows RWMA (graft occlusion), valve dysfunction, or tamponade 7. Return to Theatre: For graft revision, valve re-repair, or evacuation of haematoma

Escalation Criteria:

• CI less than 2.0 despite dobutamine 10 mcg/kg/min + adrenaline
• Rising lactate despite optimisation
• Oliguria/anuria
• Mixed venous saturation less than 50%
• Requirement for high-dose adrenaline (greater than 0.2 mcg/kg/min)

d) Mechanical Circulatory Support (2 marks)

Indications:

• Refractory LCOS despite maximal inotropic support
• CI less than 1.8 L/min/m2 with organ dysfunction
• Failure to wean from CPB (would have been addressed intra-operatively)

Options:

1. IABP: First-line, diastolic augmentation, limited efficacy
2. VA-ECMO: Most commonly used; provides full circulatory support; survival 30-40%
3. Impella: LV unloading; can be combined with ECMO (ECMELLA)
4. CentriMag/TandemHeart: Short-term VAD options

---

SAQ 2: Cardiac Tamponade (15 marks)

Question: A 58-year-old female is day 1 post-mitral valve repair. She has been stable overnight but at 0800, the nursing staff note the following changes over 30 minutes:

• MAP fallen from 75 to 52 mmHg
• HR increased from 80 to 115 bpm (sinus tachycardia)
• CVP risen from 8 to 16 mmHg
• Chest drain output has decreased from 50 mL/hr to 10 mL/hr in last hour
• Urine output decreased to 5 mL in last hour
• Noradrenaline increased from 0.05 to 0.2 mcg/kg/min with minimal response

a) What is the most likely diagnosis and what are the differential diagnoses? (2 marks)

b) What clinical and echocardiographic features support the diagnosis of cardiac tamponade? (4 marks)

c) Describe the immediate management of this patient. (5 marks)

d) The patient suffers a cardiac arrest (PEA). Describe the management. (4 marks)

---

Model Answer:

a) Most Likely Diagnosis and Differentials (2 marks)

Most Likely: Cardiac Tamponade

• Classic presentation: Sudden decrease in drain output + haemodynamic collapse + rising CVP

Differentials:

• Massive pulmonary embolism (but CVP would be high with RV strain)
• Tension pneumothorax (unilateral breath sounds, tracheal deviation)
• Acute MI/graft occlusion (ST changes)
• Sepsis (but too early, and CVP would be low/normal initially)
• Prosthetic valve thrombosis/dysfunction

b) Clinical and Echo Features of Tamponade (4 marks)

Clinical Features:

• Hypotension with narrow pulse pressure
• Tachycardia
• Elevated JVP/CVP (Kussmaul's sign - JVP rises on inspiration)
• Pulsus paradoxus greater than 10 mmHg (difficult in ventilated patients)
• Muffled heart sounds (difficult to assess post-sternotomy)
• Sudden decrease in chest drain output (pathognomonic in post-cardiac surgery)
• Equalisation of diastolic pressures (CVP ≈ PADP ≈ PCWP) if PA catheter present

Echocardiographic Features:

• Pericardial effusion/haematoma (may be loculated, not circumferential)
• Right atrial collapse in late diastole (most sensitive)
• Right ventricular diastolic collapse (most specific)
• IVC plethora (greater than 2.5 cm) without respiratory variation
• Septal "bounce" with respiration
• Reduced mitral and tricuspid inflow velocities on inspiration

Important: Absence of classical echo findings does not exclude loculated tamponade post-cardiac surgery

c) Immediate Management (5 marks)

IMMEDIATE ACTIONS:
1. Call for HELP
   - Cardiac surgeon (on-call and primary)
   - Senior ICU consultant
   - Anaesthetist/airway support
   - Theatre team (standby for return to theatre)

2. Supportive Measures (Bridge to Definitive Treatment):
   - 100% FiO2
   - Volume loading (aggressive IV fluid to maintain preload)
   - Vasopressor support (noradrenaline/adrenaline)
   - Reduce/stop positive pressure ventilation if possible
   - Reduce PEEP to minimum
   - Avoid excessive sedation that causes vasodilation

3. URGENT Echo (if not already done):
   - Confirm diagnosis
   - Do NOT delay definitive treatment for imaging if clinical picture clear

4. Strip/Milk Chest Drains:
   - May relieve clotted drain
   - If successful (sudden drainage), may temporise

5. DEFINITIVE TREATMENT = SURGICAL:
   - If stable: Urgent return to operating theatre for sternotomy
   - If unstable: Prepare for bedside emergency resternotomy

d) PEA Cardiac Arrest Management (4 marks)

Timing: Emergency resternotomy should occur within 5 minutes of cardiac arrest (PMID: 28122234)

Algorithm:

1. Confirm Arrest: Unresponsive, no pulse, no cardiac output on arterial trace

2. Call for Help: Cardiac surgeon, crash team

3. External CPR: Start standard CPR (modified technique - direct sternal compression)

4. Ventilation: 100% O2

5. Adrenaline: 1 mg IV bolus (standard ACLS protocol)

6. EMERGENCY RESTERNOTOMY:

   • Open sternotomy kit (must be at bedside for all post-cardiac surgery patients)
   • Don sterile gloves (full aseptic technique if time allows)
   • Cut sternal wires with wire cutters
   • Insert sternal retractor
   • Evacuate clot manually
   • Internal cardiac massage
   • Control any bleeding source
   • Internal defibrillation if VF (20J internal paddles)

7. Post-ROSC:

   • Transport to operating theatre for definitive repair
   • Continue supportive care

Equipment Required at Bedside:

• Resternotomy tray
• Wire cutters
• Sternal retractor
• Internal defibrillator paddles
• Suture materials

---

Hot Case Scenarios

Hot Case 1: Day 1 Post-CABG with Low Cardiac Output

Setting: Cardiac surgical ICU

Scenario: You are asked to review a 65-year-old male, Day 1 post-CABG x4 (LIMA-LAD, SVG-OM, SVG-RCA, SVG-Diagonal). He has a background of type 2 diabetes, hypertension, and pre-operative EF 45%.

Bedside Findings:

• Intubated, sedated (propofol/fentanyl), pacing at 80 (capture confirmed)
• Arterial line: BP 85/55 mmHg (MAP 65)
• CVP: 12 mmHg
• PA catheter: CO 3.8 L/min, CI 1.9 L/min/m2, PCWP 18 mmHg, SVR 1600 dyn.s.cm-5
• Infusions: Noradrenaline 0.2 mcg/kg/min, dobutamine 8 mcg/kg/min
• Urine output: 20 mL in last 2 hours
• Chest drains: 60 mL in last hour (sanguinous)
• Lactate: 3.8 mmol/L (trending up from 2.4 mmol/L 4 hours ago)
• Temperature: 36.2°C

Task: Present your assessment and management plan.

---

Model Presentation:

Opening Statement: "This is a 65-year-old male, Day 1 post-CABG x4, who is demonstrating low cardiac output syndrome with a cardiac index of 1.9 L/min/m2 despite dual inotrope/vasopressor support. He is showing signs of end-organ hypoperfusion with oliguria and rising lactate."

Systematic Assessment:

A - Airway: ETT in situ, secured

B - Breathing: Ventilated, satisfactory oxygenation (I would check the ABG)

C - Circulation:

• Haemodynamic State: Low cardiac output (CI 1.9), adequate preload (PCWP 18), high SVR (1600) - consistent with cardiogenic shock
• Trend: Deteriorating (rising lactate, increasing vasopressor requirements)
• ECG: I would examine for any ST changes concerning for graft occlusion
• Chest drains: Satisfactory output, no evidence of acute tamponade
• Pacing: Capturing appropriately

D - Disability: Sedated, pupils reactive (I would assess underlying neurology)

E - Exposure: Temperature 36.2°C - normothermic

Key Concerns:

1. LCOS with end-organ dysfunction
2. Need to exclude surgical causes (graft occlusion, tamponade)
3. Rising lactate indicating inadequate tissue oxygen delivery

Investigations I Would Request:

• ABG (confirm lactate, assess oxygenation, acid-base)
• 12-lead ECG (compare to immediate post-op for ST changes)
• Bedside echocardiography (ventricular function, RWMA, valve function, tamponade)
• FBC, coagulation (assess for ongoing bleeding, coagulopathy)

Management Plan:

1. Immediate:

   • Complete active warming to 37°C
   • Optimise preload (PCWP 18 is adequate; avoid further fluid loading)
   • Continue current inotropic support

2. Escalation:

   • Increase dobutamine to 10 mcg/kg/min
   • If inadequate response, add adrenaline 0.05-0.1 mcg/kg/min
   • Target CI greater than 2.2 L/min/m2, MAP greater than 65 mmHg

3. If Echo Shows RWMA (Graft Concern):

   • Urgent cardiology/surgical review
   • Consider return to theatre vs coronary angiography

4. If Refractory to Medical Management:

   • Discuss mechanical circulatory support with cardiac surgeon
   • VA-ECMO consideration if CI remains less than 1.8 despite maximal therapy

5. Ongoing Monitoring:

   • Hourly lactate trending
   • Continuous haemodynamic monitoring (CI, SVR, SvO2)
   • Urine output (target greater than 0.5 mL/kg/hr)

Communication:

• Update family on current status and concerns
• Discuss escalation plans including potential for return to theatre or ECMO

---

Hot Case 2: Postoperative Atrial Fibrillation with Haemodynamic Compromise

Setting: Cardiac surgical ICU

Scenario: You are called to review a 70-year-old female, Day 2 post-aortic valve replacement (bioprosthetic). She was extubated yesterday and was doing well until 30 minutes ago when she developed sudden palpitations and shortness of breath.

Bedside Findings:

• Awake, anxious, diaphoretic
• BP 85/60 mmHg (was 120/70 earlier today)
• HR 155 bpm, irregularly irregular
• SpO2 92% on 4 L nasal prongs
• RR 28/min
• JVP elevated
• Lungs: Bibasal crackles
• Chest drains removed yesterday
• 12-lead ECG: AF with rapid ventricular response, no ST changes

Task: Present your assessment and management plan.

---

Model Presentation:

Opening Statement: "This is a 70-year-old female, Day 2 post-bioprosthetic AVR, who has developed new-onset atrial fibrillation with rapid ventricular response causing haemodynamic compromise. She is hypotensive, hypoxic, and showing signs of acute pulmonary oedema."

Assessment:

A - Airway: Self-maintaining

B - Breathing: Tachypnoeic, hypoxic, bibasal crackles suggestive of pulmonary oedema

C - Circulation:

• Rhythm: AF with RVR at 155 bpm
• Haemodynamic State: Hypotensive (MAP ~68), showing signs of poor perfusion
• Assessment: This is POAF causing acute haemodynamic decompensation
• Cause: Post-operative AF is common (30-40% post-valve surgery), but this is symptomatic

D - Disability: Awake, anxious

Management:

Immediate Actions:

1. Oxygen: High-flow oxygen, target SpO2 greater than 94%
2. IV Access: Confirm patent IV access
3. Monitoring: Continuous ECG, arterial line if not present

Definitive Treatment - DC Cardioversion: Given haemodynamic compromise, this patient requires synchronised DC cardioversion:

• Procedural sedation (propofol/midazolam + fentanyl)
• Synchronized shock 150-200 J biphasic
• Have crash cart ready
• Post-cardioversion: 12-lead ECG, monitor for recurrence

If Cardioversion Successful:

• Antiarrhythmic to maintain sinus: Amiodarone 300 mg IV over 1 hour, then 900 mg/24h
• Restart beta-blocker (metoprolol 12.5-25 mg BD)
• Electrolyte correction (K+ greater than 4.0, Mg greater than 1.0)
• Diuresis for pulmonary oedema (furosemide 20-40 mg IV)

If Cardioversion Unsuccessful or AF Recurs:

• Rate control: Amiodarone infusion, or diltiazem (avoid if HFrEF), or digoxin
• Target HR less than 110 bpm
• Consider echo to assess LV function, valve function

Anticoagulation Considerations:

• AF present less than 48 hours: Low risk of thrombus; can cardiovert without anticoagulation
• If AF persists greater than 48 hours: Anticoagulation required (balance with post-op bleeding risk)
• CHA2DS2-VASc scoring for ongoing anticoagulation decision

Prevention of Recurrence:

• Identify precipitants (hypovolaemia, electrolyte disturbance, pain, infection)
• Continue amiodarone for 5-7 days
• Ensure beta-blocker restarted and uptitrated

---

Viva Scenarios

Viva 1: Vasoplegia and Methylene Blue

Examiner: "A 62-year-old male is 6 hours post-CABG x3. He is on noradrenaline 0.5 mcg/kg/min and vasopressin 0.04 U/min with a MAP of 58 mmHg. His PA catheter shows CI 3.2 L/min/m2 and SVR 520 dyn.s.cm-5. Lactate is 3.2 mmol/L. Echo shows hyperdynamic LV function, no effusion. Tell me about this clinical picture."

Candidate: "This patient is demonstrating vasoplegic syndrome - characterised by low systemic vascular resistance with normal or elevated cardiac output, despite high-dose vasopressor support. The cardiac index of 3.2 is actually supranormal, yet he remains hypotensive due to profound vasodilation."

Examiner: "What causes vasoplegia after cardiac surgery?"

Candidate: "Vasoplegia is caused by excessive nitric oxide production triggered by the systemic inflammatory response to cardiopulmonary bypass. Inducible nitric oxide synthase is upregulated, leading to increased NO which activates soluble guanylate cyclase, increasing cyclic GMP and causing vascular smooth muscle relaxation.

There is also relative vasopressin deficiency post-bypass, and potential contribution from relative adrenal insufficiency.

Risk factors include pre-operative ACE inhibitor or ARB use - which is probably the most important modifiable risk factor - low preoperative ejection fraction, prolonged CPB time, and heart failure."

Examiner: "He was on ramipril preoperatively. What would you do next?"

Candidate: "Given refractory vasoplegia despite noradrenaline and vasopressin at maximal doses, I would consider rescue therapy with methylene blue.

Before administration, I would confirm no contraindications - specifically G6PD deficiency which causes severe haemolysis, and concomitant serotonergic medications such as SSRIs or SNRIs which risk precipitating serotonin syndrome.

Assuming no contraindications, I would administer methylene blue 1.5 to 2 mg/kg as an IV bolus over 10-20 minutes."

Examiner: "What is the mechanism of action of methylene blue?"

Candidate: "Methylene blue works by inhibiting soluble guanylate cyclase. Normally, nitric oxide binds to this enzyme, activating it and increasing production of cyclic GMP, which causes vasodilation. By blocking guanylate cyclase, methylene blue prevents the cGMP-mediated vasodilation, thereby restoring vascular tone.

It also has a lesser effect of directly inhibiting nitric oxide synthase, reducing NO production."

Examiner: "The bedside nurse notices the SpO2 has dropped to 82% after methylene blue. The patient looks pink. What do you think?"

Candidate: "This is an artefact. Methylene blue interferes with pulse oximetry due to its blue colour absorbing light at wavelengths used by the oximeter. The patient appearing pink suggests adequate oxygenation - I would check an arterial blood gas for co-oximetry to confirm the true oxygen saturation, which I expect will be normal.

I would reassure the nursing staff and document this expected phenomenon."

Examiner: "The patient improves. Any other considerations?"

Candidate: "I would monitor for response - typically seen within 30-60 minutes - and wean vasopressors as able. If the response is transient, I may consider a repeat bolus or a continuous infusion at 0.25-0.5 mg/kg/hour.

I would also consider hydrocortisone 100 mg IV eight-hourly if vasopressor requirements remain high, to address potential relative adrenal insufficiency.

On a systems level, I would ensure this patient's use of ACE inhibitors preoperatively is noted for future cardiac surgery risk assessment, as this is a modifiable risk factor."

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Viva 2: Post-Cardiac Surgery Bleeding and Transfusion

Examiner: "A patient is 2 hours post-CABG x4. The chest drain has put out 400 mL in the first hour and 320 mL in the second hour. How do you approach this?"

Candidate: "This is concerning bleeding. Output greater than 400 mL in the first hour, or greater than 300 mL per hour for 2 consecutive hours, meets criteria for potential surgical re-exploration.

My approach would be:

First, assess the patient haemodynamically - are they stable? Check blood pressure, heart rate, CVP, and whether there is any suggestion of tamponade developing.

Second, assess and correct coagulopathy. I would send or review the point-of-care testing - TEG or ROTEM if available - and conventional coagulation studies. Key questions:

• Is there residual heparin effect? Check ACT.
• Is there coagulation factor deficiency? Assess PT/INR, APTT, and TEG parameters.
• Is there platelet dysfunction? Platelet count and TEG.
• Is there hypofibrinogenaemia? Fibrinogen level and FIBTEM if ROTEM available.
• Is there hyperfibrinolysis? LY30 on TEG or ML on ROTEM."

Examiner: "The TEG shows a prolonged R-time and low MA. Fibrinogen is 1.2 g/L. Platelets are 85 x 10^9/L. What does this mean and what would you give?"

Candidate: "This pattern indicates:

1. Prolonged R-time suggests factor deficiency - I would give FFP 10-15 mL/kg or consider PCC if rapid reversal needed
2. Low MA with low fibrinogen indicates fibrinogen deficiency contributing to weak clot - I would give cryoprecipitate (1 pool per 5-10 kg) or fibrinogen concentrate to target fibrinogen greater than 2 g/L
3. The platelet count of 85 is above usual transfusion threshold, but in the context of ongoing bleeding, I would give a platelet transfusion to target greater than 100 x 10^9/L

I would also ensure tranexamic acid has been given - this should be routine in cardiac surgery to reduce fibrinolysis."

Examiner: "After blood product administration, the TEG normalises but bleeding continues at 250 mL/hour. What now?"

Candidate: "With corrected coagulopathy but persistent bleeding at 250 mL/hour - which exceeds the 200 mL/hour for 3 consecutive hours threshold - this is likely surgical bleeding rather than coagulopathy.

I would:

1. Notify the cardiac surgeon immediately
2. Prepare for potential return to theatre for re-exploration
3. Ensure the patient is cross-matched with blood products available
4. Continue monitoring for haemodynamic deterioration

The indication for re-exploration is now clear - corrected coagulopathy with ongoing significant bleeding indicates a surgical source."

Examiner: "What are the outcomes associated with re-exploration?"

Candidate: "Re-exploration for bleeding occurs in approximately 3-5% of cardiac surgery patients and is associated with increased morbidity and mortality.

Mortality is 2-3 times higher than uncomplicated surgery. Complications include increased transfusion requirements, acute kidney injury, prolonged ventilation, infection, and increased ICU and hospital length of stay.

Importantly, delayed re-exploration has worse outcomes than early re-exploration. If the decision for re-exploration is made, it should be performed promptly."

Examiner: "What transfusion threshold would you use for red cells in this patient?"

Candidate: "The TRICS III trial, published in 2017, established that a restrictive transfusion strategy with a haemoglobin trigger of less than 75 g/L is non-inferior to a liberal strategy with a trigger of less than 95 g/L in cardiac surgery patients.

Therefore, I would use a restrictive threshold - transfusing when haemoglobin falls below 75 g/L, targeting 75-90 g/L. However, in the context of active bleeding with haemodynamic instability, I would be more liberal to maintain adequate oxygen delivery while awaiting surgical control."

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Australian/New Zealand Context

ANZSCTS Database

The Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) maintains a comprehensive cardiac surgery database:

• Coverage: 23 Australian and 2 New Zealand hospitals
• Data: Outcomes, complications, mortality rates
• Quality Improvement: Benchmarking, feedback to units
• Risk Adjustment: Australian-specific risk models

Australian Cardiac Surgery Outcomes:

• Isolated CABG 30-day mortality: 1-2%
• Isolated AVR 30-day mortality: 1-3%
• Combined CABG + valve: 3-5%
• Comparable to international benchmarks

Indigenous Health Considerations

Aboriginal and Torres Strait Islander patients have higher rates of cardiovascular disease and present at younger ages (PMID: 27884807, 22722715):

Key Statistics:

• 2-3 times higher rates of coronary artery disease
• Higher rates of rheumatic heart disease
• Present with MI 10-15 years younger than non-Indigenous Australians
• Often have more advanced disease at presentation
• Higher rates of diabetes, renal disease as comorbidities

Cultural Considerations in Cardiac Surgery ICU:

1. Family and Community:

   • Extended family involvement in care decisions
   • May need to accommodate larger family groups for discussions
   • Decision-making may be collective rather than individual

2. Communication:

   • Aboriginal Health Worker or Aboriginal Liaison Officer involvement
   • Interpreter services (multiple Indigenous languages)
   • Plain language, avoid medical jargon
   • Time for yarning and relationship-building

3. Cultural Safety:

   • Acknowledge cultural identity
   • Awareness of Sorry Business (bereavement) that may affect patient or family
   • Respect for gender considerations (same-sex care providers if preferred)
   • Connection to Country - understand patient may be far from home

4. Barriers to Care:

   • Geographic isolation - patients may have travelled significant distance
   • Family may be unable to visit if from remote communities
   • Socioeconomic factors affecting post-discharge care
   • Higher rates of leaving against medical advice - address underlying concerns

Māori Health Considerations (New Zealand):

1. Whānau (Family): Central to decision-making; whānau hui (family meetings) may be needed
2. Tikanga: Cultural protocols and practices - respect for these
3. Health Equity: Māori have higher rates of cardiovascular disease; address systemic inequities
4. Māori Health Workers: Invaluable for cultural liaison and support

Retrieval Medicine Considerations

For patients requiring inter-hospital transfer for cardiac surgery or post-operative complications:

1. Pre-Transfer Stabilisation:

   • Haemodynamic stabilisation
   • Chest drain management (never clamp for transfer if active air leak)
   • Pacing: Ensure stable capture if pacemaker-dependent
   • Sedation and analgesia optimisation

2. ECMO Retrieval:

   • ECMO services available in major centres (Sydney, Melbourne, Brisbane, Adelaide, Perth, Auckland)
   • Mobile ECMO teams can retrieve from referring hospitals
   • Coordination through state retrieval services

3. Communication:

   • Direct consultant-to-consultant handover
   • All relevant documentation including operative notes
   • Clear management plan during transfer

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References

Core Guidelines and Consensus Statements

1. Engelman DT, et al. Guidelines for Perioperative Care in Cardiac Surgery: Enhanced Recovery After Surgery Society Recommendations. JAMA Surg. 2019;154(8):755-766. PMID: 31054241

2. Lomivorotov VV, et al. Low-Cardiac-Output Syndrome After Cardiac Surgery. J Cardiothorac Vasc Anesth. 2017;31(4):1398-1413. PMID: 28392182

3. Busse LW, et al. Vasoplegic syndrome following cardiothoracic surgery - review of pathophysiology and update on treatment options. Crit Care. 2020;24(1):324. PMID: 32522250

4. Boer C, et al. 2017 EACTS/EACTA Guidelines on patient blood management for adult cardiac surgery. Eur J Cardiothorac Surg. 2018;53(1):79-111. PMID: 28939101

5. Tibi P, et al. STS/SCA/AmSECT/SABM Clinical Practice Guidelines on Patient Blood Management. J Cardiothorac Vasc Anesth. 2021;35(12):3516-3574. PMID: 34921903

Landmark Trials

6. Mazer CD, et al. Restrictive or Liberal Red-Cell Transfusion for Cardiac Surgery (TRICS III). N Engl J Med. 2017;377(22):2133-2144. PMID: 29130845

7. Dunning J, et al. Guidelines on the management of resuscitation in cardiac surgery: EACTS Guidelines. Eur J Cardiothorac Surg. 2017;51(5):809-816. PMID: 28122234

8. Levin RL, et al. Methylene blue reduces mortality and morbidity in vasoplegic patients after cardiac surgery. Ann Thorac Surg. 2004;77(2):496-499. PMID: 15607433

Atrial Fibrillation

9. Gillinov AM, et al. Rate Control versus Rhythm Control for Atrial Fibrillation after Cardiac Surgery. N Engl J Med. 2016;374(20):1911-1921. PMID: 27043047

10. Arsenault KA, et al. Interventions for preventing post-operative atrial fibrillation in patients undergoing heart surgery. Cochrane Database Syst Rev. 2013;(1):CD003611. PMID: 23395017

11. Giri S, et al. Oral amiodarone for prevention of atrial fibrillation after open heart surgery, the Atrial Fibrillation Suppression Trial (ARCH): a randomised placebo-controlled trial. Lancet. 1999;354(9187):1435-1436. PMID: 10543670

12. Mitchell LB, et al. Prophylaxis of supraventricular tachyarrhythmias after coronary artery bypass grafting with intravenous amiodarone (ARCH trial). Circulation. 2004;110(11 Suppl 1):II94-99. PMID: 15306214

13. January CT, et al. 2019 AHA/ACC/HRS Focused Update. Circulation. 2019;140(2):e125-e151. PMID: 30686041

ECMO and Mechanical Support

14. Lorusso R, et al. In-hospital and mid-term outcomes of post-cardiotomy ECMO in the Extracorporeal Life Support Organization Registry. Eur J Cardiothorac Surg. 2020;57(6):1052-1060. PMID: 31932135

15. Biancari F, et al. Multicenter Study on Postcardiotomy Venoarterial Extracorporeal Membrane Oxygenation (PC-ECMO). JACC Heart Fail. 2020;8(11):945-954. PMID: 33121910

16. Guglin M, et al. Venoarterial ECMO for Adults: JACC Scientific Expert Panel. J Am Coll Cardiol. 2019;73(6):698-716. PMID: 30765037

17. ELSO Registry Report 2022. PMID: 36326262

Renal

18. Hertzberg D, et al. Acute kidney injury is associated with postoperative delirium and 1-year mortality after cardiac surgery. Eur J Cardiothorac Surg. 2022;61(5):1012-1020. PMID: 35147493

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

Neurological

20. Gammelager H, et al. One-year mortality among Danish intensive care patients with acute kidney injury: a cohort study. Crit Care. 2012;16(4):R124. PMID: 22789072

21. Brown CH, et al. The Association Between Preoperative Frailty and Postoperative Delirium After Cardiac Surgery. Anesth Analg. 2016;123(2):430-435. PMID: 27096558

Infection

22. Edwards FH, et al. The Society of Thoracic Surgeons Practice Guideline Series: Antibiotic Prophylaxis in Cardiac Surgery, Part I: Duration. Ann Thorac Surg. 2006;81(1):397-404. PMID: 27150242

23. Lador A, et al. Antibiotic prophylaxis in cardiac surgery: systematic review and meta-analysis. J Antimicrob Chemother. 2012;67(3):541-550. PMID: 22155607

Handover and Quality

24. Joy BF, et al. Standardized multidisciplinary protocol improves handover of cardiac surgery patients to the intensive care unit. Pediatr Crit Care Med. 2011;12(3):304-308. PMID: 21255531

25. Segall N, et al. Operating room-to-ICU patient handovers: A multidisciplinary human-centered design approach. Jt Comm J Qual Patient Saf. 2016;42(9):400-414. PMID: 27543909

Vasoplegia

26. Leite JC, et al. Methylene blue for vasoplegic syndrome: a meta-analysis with trial sequential analysis. Minerva Anestesiol. 2016;82(3):301-307. PMID: 27103394

27. Evora PR, et al. Methylene blue for vasoplegic syndrome treatment in heart surgery: fifteen years of questions, answers, doubts and certainties. Rev Bras Cir Cardiovasc. 2009;24(3):279-288. PMID: 20011872

Blood Management

28. Dyke C, et al. Universal definition of perioperative bleeding in adult cardiac surgery. J Thorac Cardiovasc Surg. 2014;147(5):1458-1463.e1. PMID: 24411601

29. Karkouti K, et al. Point-of-Care Hemostatic Testing in Cardiac Surgery: A Stepped-Wedge Clustered Randomized Controlled Trial. Circulation. 2016;134(16):1152-1162. PMID: 27654344

Additional References

30. Algarni KD, et al. Risk factors and prognosis of vasoplegia after cardiac surgery. Ann Card Anaesth. 2015;18(4):453-458. PMID: 26440728

31. Shaefi S, et al. Vasoplegia After Cardiovascular Procedures - Pathophysiology and Targeted Therapy. J Cardiothorac Vasc Anesth. 2018;32(2):1013-1022. PMID: 29235942

32. Fiser SM, et al. A 20-year experience with postoperative extracorporeal membrane oxygenation for adult cardiac surgery. Ann Thorac Surg. 2001;72(3):S1019-1024. PMID: 11598027

33. Wernovsky G, et al. Postoperative course and hemodynamic profile after the arterial switch operation in neonates and infants. Circulation. 1995;92(8):2226-2235. PMID: 7554206

34. Argenziano M, et al. Randomized, double-blind trial of inhaled nitric oxide in LVAD recipients with pulmonary hypertension. Ann Thorac Surg. 1998;65(2):340-345. PMID: 9485226

35. Hajjar LA, et al. Vasopressin versus Norepinephrine in Patients with Vasoplegic Shock after Cardiac Surgery: The VANCS Randomized Controlled Trial. Anesthesiology. 2017;126(1):85-93. PMID: 27841822

36. Mangano DT, et al. Aspirin and mortality from coronary bypass surgery. N Engl J Med. 2002;347(17):1309-1317. PMID: 12397188

37. Ferguson TB Jr, et al. A decade of change - risk profiles and outcomes for isolated coronary artery bypass grafting procedures, 1990-1999: a report from the STS National Database Committee and the Duke Clinical Research Institute. Ann Thorac Surg. 2002;73(2):480-490. PMID: 11845863

38. Brown JR, et al. Multivariable prediction of renal insufficiency developing after cardiac surgery. Circulation. 2007;116(11 Suppl):I139-143. PMID: 17846294

39. Mehta RH, et al. Reoperation for bleeding in patients undergoing coronary artery bypass surgery: incidence, risk factors, time trends, and outcomes. Circ Cardiovasc Qual Outcomes. 2009;2(6):583-590. PMID: 20031896

40. Ranucci M, et al. Surgical reexploration after cardiac operations: why a worse outcome? Ann Thorac Surg. 2008;86(5):1557-1562. PMID: 19049749

41. Vivacqua A, et al. Morbidity of bleeding after cardiac surgery: is it blood transfusion, reoperation for bleeding, or both? Ann Thorac Surg. 2011;91(6):1780-1790. PMID: 21619974

42. Karkouti K, et al. Hemodilution during cardiopulmonary bypass is an independent risk factor for acute renal failure in adult cardiac surgery. J Thorac Cardiovasc Surg. 2005;129(2):391-400. PMID: 15678051

43. Laffey JG, et al. The Systemic Inflammatory Response to Cardiac Surgery: Implications for the Anesthesiologist. Anesthesiology. 2002;97(1):215-252. PMID: 12131125

44. Maganti M, et al. Predictors of low cardiac output syndrome after isolated aortic valve surgery. Circulation. 2005;112(9 Suppl):I448-452. PMID: 16159861

45. Rao V, et al. Predictors of low cardiac output syndrome after coronary artery bypass. J Thorac Cardiovasc Surg. 1996;112(1):38-51. PMID: 8691884

46. Algarni KD, et al. Decreasing prevalence but increasing importance of left ventricular dysfunction and reoperative surgery in prediction of mortality in coronary artery bypass surgery: trends over 18 years. J Thorac Cardiovasc Surg. 2012;144(2):340-346. PMID: 21983374

47. Hollenberg SM. Vasoactive drugs in circulatory shock. Am J Respir Crit Care Med. 2011;183(7):847-855. PMID: 21097695

48. Guarracino F, et al. Norepinephrine versus Vasopressin versus Norepinephrine plus Vasopressin for Vasoplegia after Cardiac Surgery. J Cardiothorac Vasc Anesth. 2014;28(3):506-512. PMID: 24315765

49. Kiziltepe U, et al. Antioxidant vitamin treatment after cardiac surgery. Ann Clin Lab Sci. 2004;34(4):467-470. PMID: 15648790

50. Society of Thoracic Surgeons Blood Conservation Guideline Task Force. Blood conservation clinical practice guidelines for cardiothoracic surgery. Ann Thorac Surg. 2007;83(5 Suppl):S27-86. PMID: 17462454

51. Paparella D, et al. Coagulation disorders of cardiopulmonary bypass: a review. Intensive Care Med. 2004;30(10):1873-1881. PMID: 15278267

52. Despotis GJ, et al. Clinical application of point-of-care testing for cardiovascular surgery. J Cardiothorac Vasc Anesth. 2002;16(6):673-685. PMID: 12486645

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Related Topics

• Low Cardiac Output Syndrome
• Cardiogenic Shock
• Cardiac Tamponade
• Atrial Fibrillation in ICU
• ECMO
• Coagulopathy in ICU
• Acute Kidney Injury
• Renal Replacement Therapy
• Delirium in ICU
• Ventilator Management