Sedation and Analgesia Protocols in ICU

1. Quick Answer

Sedation and analgesia protocols in the ICU follow an "analgesia-first" approach targeting light sedation (RASS -2 to 0) using validated assessment tools. The SCCM PADIS Guidelines 2018 represent the evidence-based standard, emphasizing Pain, Agitation/sedation, Delirium, Immobility, and Sleep disruption.

Key Principles:

• Assess pain with BPS/CPOT (non-verbal) or NRS (verbal) before sedation
• Target light sedation (RASS -2 to 0) unless specific indications for deeper sedation
• Daily Sedation Interruption (SAT) paired with Spontaneous Breathing Trials (SBT)
• Avoid benzodiazepines as first-line; prefer propofol or dexmedetomidine
• Implement ABCDEF bundle for ICU liberation

ICU Mortality Impact: Deep sedation increases mortality by ~10% per RASS point below -2 (PMID: 22016520).

Must-Know Facts:

• RASS target -2 to 0 for most ventilated patients
• BPS score ≥5 or CPOT ≥3 indicates significant pain requiring treatment
• Dexmedetomidine reduces delirium duration vs. benzodiazepines (MENDS trial)
• Daily sedation interruption reduces ventilator days by 2.4 days (Kress trial)

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2. CICM Exam Focus

What Examiners Expect

Second Part Written (SAQ):

Common SAQ stems:

• "A 68-year-old male on Day 3 of mechanical ventilation for pneumonia is agitated with RASS +2. Outline your approach to assessment and management."
• "Discuss the evidence for light sedation strategies in mechanically ventilated ICU patients."
• "Compare and contrast propofol, dexmedetomidine, and midazolam for ICU sedation."
• "A patient develops unexplained metabolic acidosis and triglyceridemia on Day 5 of propofol infusion. Describe your differential and management."

Expected depth:

• Systematic pain and sedation assessment using validated tools
• Pharmacology of sedative agents including context-sensitive half-times
• Evidence from landmark trials (Kress, SLEAP, SPICE III, MENDS)
• PADIS guideline recommendations
• Complications of oversedation and specific agents

Second Part Hot Case:

Typical presentations:

• Ventilated patient who is difficult to wean due to agitation
• Day 5 post-operative patient with hyperactive delirium
• Patient with bronchospasm on propofol requiring agent switch
• Sedated patient with unexplained metabolic acidosis

Examiners assess:

• Systematic sedation and pain assessment at bedside
• Recognition of over/under-sedation using RASS
• Drug choice justification based on patient factors
• Awareness of complications (PRIS, delirium, ICUAW)
• Communication about sedation goals with family

Second Part Viva:

Expected discussion areas:

• PADIS guidelines 2018 - recommendations and evidence
• Pharmacology of sedative agents (receptors, metabolism, context-sensitive half-time)
• Daily sedation interruption - evidence, contraindications, protocol
• Delirium prevention and the role of sedation choices
• Regional analgesia in ICU - indications and evidence

Examiner expectations:

• Cite PADIS 2018, Kress, SLEAP, MENDS, SPICE III trials
• Demonstrate safe consultant-level decision-making
• Address Indigenous health considerations for sedation/analgesia

Common Mistakes

• Using deep sedation (RASS -4/-5) as default target
• Defaulting to benzodiazepines rather than propofol/dexmedetomidine
• Failing to assess pain before adjusting sedation
• Not knowing contraindications to daily sedation interruption
• Inability to describe PRIS clinical features and management

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3. Key Points

Must-Know Facts

1. Analgesia-First Approach: Treat pain before sedation; 50-70% of ICU patients have significant pain, and untreated pain causes agitation often mistaken for need for deeper sedation (PMID: 11445675).

2. RASS Target -2 to 0: Light sedation reduces mortality, ventilator days, and delirium compared to deep sedation (RASS -4/-5). SLEAP trial showed 2.4 fewer ventilator days (PMID: 22016520).

3. BPS/CPOT for Non-Verbal Patients: Behavioral Pain Scale (BPS: 3-12) and Critical Care Pain Observation Tool (CPOT: 0-8) are validated for patients unable to self-report. BPS ≥5 or CPOT ≥3 indicates clinically significant pain (PMID: 19542879).

4. Avoid Benzodiazepines First-Line: Midazolam increases delirium risk 2-3 fold compared to propofol or dexmedetomidine. Reserve for seizures, alcohol withdrawal, or when other agents contraindicated (PMID: 19926799).

5. Dexmedetomidine for Delirium Prevention: MENDS trial showed dexmedetomidine reduced delirium duration compared to lorazepam (PMID: 17993652). SPICE III showed no mortality difference vs usual care but confirmed safety (PMID: 30576417).

6. Daily Sedation Interruption (DSI): Kress 2000 trial showed DSI reduces ventilator days by 2.4 days and ICU LOS by 3.5 days (PMID: 10816189). Contraindicated in seizures, raised ICP, severe respiratory failure, paralysis, alcohol withdrawal.

7. PADIS 2018 Guidelines: SCCM guidelines recommend analgesia-first, light sedation, non-benzodiazepine agents, protocolized sedation with daily assessment, and delirium monitoring (PMID: 30113379).

8. Propofol Infusion Syndrome (PRIS): Risk increases with doses >4 mg/kg/hr for >48 hours. Features: metabolic acidosis, rhabdomyolysis, hyperlipidemia, bradyarrhythmias, cardiac failure. Mortality 33-80%. Immediate cessation of propofol is essential (PMID: 19318366).

9. Ketamine as Adjunct: Low-dose ketamine (0.1-0.5 mg/kg/hr) reduces opioid requirements by 25-50% via NMDA antagonism. Useful for opioid tolerance or chronic pain patients (PMID: 31638442).

10. ABCDEF Bundle: Comprehensive ICU liberation strategy - Assess/manage pain, Both SAT+SBT, Choice of sedation, Delirium monitoring, Early mobility, Family engagement. Improves survival and reduces delirium (PMID: 27695824).

Memory Aids

PADIS Mnemonic: Pain → Agitation → Delirium → Immobility → Sleep

• Pain assessment and treatment first
• Agitation/sedation targeting light sedation
• Delirium prevention and management
• Immobility prevention (early mobilization)
• Sleep promotion

Sedation Assessment - RASS:

• +4: Combative
• +3: Very agitated
• +2: Agitated
• +1: Restless
• 0: Alert and calm
• -1: Drowsy (eye opening >10 sec)
• -2: Light sedation (eye opening <10 sec)
• -3: Moderate sedation (movement to voice)
• -4: Deep sedation (movement to physical stimulation)
• -5: Unarousable

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4. Definition & Epidemiology

Definitions

Sedation: Pharmacologically induced reduction in consciousness to facilitate ventilation, reduce metabolic demand, and provide comfort. Ranges from light (arousable) to deep (unarousable) states.

Analgesia: Prevention and treatment of pain using pharmacological (opioids, non-opioids, regional) and non-pharmacological approaches.

Analgesia-First Sedation (eCASH Protocol): Early Comfort using Analgesia, minimal Sedatives, maximal Humane care. Prioritizes pain control before sedation, with goal of minimal sedative use (PMID: 27306264).

Light Sedation: RASS -2 to 0 (drowsy but arousable, or calm and cooperative). Patient can follow simple commands but tolerates mechanical ventilation.

Deep Sedation: RASS -4 to -5 (unarousable or responds only to physical stimulation). Reserved for specific indications: severe ARDS, paralysis, raised ICP, status epilepticus.

Severity Classification - RASS Scale

Epidemiology

International Data:

• Mechanical ventilation: 30-40% of ICU patients
• Sedation use in ventilated patients: 70-90%
• Deep sedation (RASS ≤-3) prevalence: 40-60% despite guidelines
• Delirium incidence in ventilated patients: 50-80%
• Pain prevalence in ICU patients: 50-70%

Australian/NZ Data (ANZICS APD):

• Median mechanical ventilation duration: 2-3 days
• Sedation-related prolonged ventilation: 15-25% of patients
• ICU-acquired weakness incidence: 25-50%
• ANZICS CORE sedation audit 2019: 68% of Australian ICUs use protocolized sedation

Risk Factors for Prolonged Sedation:

• Patient Factors: Age >65, obesity (context-sensitive half-time increased), hepatic dysfunction, renal dysfunction, hypoalbuminemia (increased unbound drug)
• Drug Factors: Benzodiazepines (accumulation), high-dose opioids, polypharmacy
• Disease Factors: ARDS requiring deep sedation, status epilepticus, neurocritical care

High-Risk Populations:

• Aboriginal and Torres Strait Islander: 2-3× higher rates of chronic pain conditions; potential for under-assessment due to communication barriers; higher rates of hepatorenal disease affecting drug metabolism (PMID: 29760987)
• Māori: Similar disparities; cultural considerations for family involvement in sedation discussions
• Remote/Rural: Limited access to multimodal analgesia options; retrieval considerations for oversedation

Outcomes:

• Deep sedation mortality: 10-15% increase per RASS point below -2
• Ventilator days: 2-4 additional days with deep vs light sedation
• ICU LOS: 1-2 additional days per RASS point deeper
• Delirium: 2× increased risk with deep sedation

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5. Applied Basic Sciences

Neuroanatomy of Consciousness and Pain

Consciousness Networks:

• Ascending Reticular Activating System (ARAS): Brainstem nuclei (locus coeruleus, raphe nuclei, pedunculopontine nucleus) → thalamus → cortex. Sedatives reduce ARAS output.
• Thalamocortical Circuits: Propofol disrupts thalamic gating of sensory information to cortex.
• Locus Coeruleus: Primary target for α2-agonists (dexmedetomidine). Produces "natural sleep-like" sedation via noradrenergic suppression.

Pain Pathways:

• Peripheral Nociceptors: Aδ (fast, sharp) and C fibers (slow, dull) transmit via dorsal root ganglia
• Spinothalamic Tract: Ascends contralaterally to thalamus
• Cortical Processing: Primary somatosensory cortex (S1), anterior cingulate cortex (affective component)
• Descending Modulation: Periaqueductal gray → rostroventral medulla → dorsal horn. Opioids enhance descending inhibition.

Pharmacology - Sedative Agents

Propofol

• Class: 2,6-diisopropylphenol in lipid emulsion
• Mechanism: GABA-A receptor positive allosteric modulator (β3 subunit binding); also inhibits NMDA receptors and voltage-gated sodium channels
• Pharmacokinetics:
  • "Onset: 30-45 seconds (rapid BBB penetration)"
  • "Distribution half-life: 2-4 minutes"
  • "Elimination half-life: 4-12 hours (hepatic conjugation)"
  • "Context-sensitive half-time: 40 min (after 8-hour infusion), increases with duration"
  • "Volume of distribution: 2-10 L/kg (highly lipophilic)"
  • "Clearance: 20-30 mL/kg/min (exceeds hepatic blood flow - extrahepatic metabolism)"
• ICU Dosing:
  • "Induction: 1.5-2.5 mg/kg (reduce in elderly/hypovolemic)"
  • "Infusion: 0.5-4 mg/kg/hr (target RASS)"
  • "Maximum: 4 mg/kg/hr for >48 hours (PRIS risk)"
• Monitoring: Triglycerides (q24-48h), CK if prolonged use, lactate, ECG
• Adverse Effects:
  • Hypotension (peripheral vasodilation, myocardial depression)
  • Bradycardia
  • Respiratory depression
  • Pain on injection (mitigated by lidocaine pre-treatment)
  • Propofol Infusion Syndrome (PRIS)
  • Hypertriglyceridemia (lipid emulsion vehicle)
• PBS/TGA: PBS listed, S4 drug

Propofol Infusion Syndrome (PRIS)

Definition: Rare but potentially fatal syndrome associated with high-dose (>4 mg/kg/hr) or prolonged (>48h) propofol infusion.

Pathophysiology:

• Impaired mitochondrial fatty acid oxidation (carnitine palmitoyltransferase I inhibition)
• Uncoupling of oxidative phosphorylation
• Impaired mitochondrial respiratory chain (complex II, coenzyme Q)

Clinical Features (PMID: 19318366):

• Metabolic acidosis (unexplained)
• Rhabdomyolysis (elevated CK >10,000)
• Hyperlipidemia (triglycerides >5 mmol/L)
• Cardiac failure (dilated cardiomyopathy)
• Bradyarrhythmias/asystole
• Renal failure (myoglobinuria)
• Hepatomegaly/fatty liver

Risk Factors:

• High-dose propofol >4 mg/kg/hr
• Duration >48 hours
• Catecholamine infusions
• Low carbohydrate intake (enhanced fatty acid reliance)
• Critical illness severity
• Pediatric patients (originally described in children)

Management:

• Immediate cessation of propofol
• Switch to alternative sedation (dexmedetomidine, midazolam)
• Supportive care: hemodynamic support, RRT for acidosis/rhabdomyolysis
• Consider ECMO for refractory cardiac failure
• Mortality: 33-80% (early recognition critical)

Midazolam

• Class: Water-soluble benzodiazepine
• Mechanism: GABA-A receptor positive allosteric modulator at α subunit benzodiazepine binding site. Enhances chloride conductance.
• Pharmacokinetics:
  • "Onset: 2-3 minutes IV"
  • "Distribution half-life: 6-15 minutes"
  • "Elimination half-life: 1.5-2.5 hours (single dose); prolonged with infusion"
  • "Context-sensitive half-time: 200-250 minutes after prolonged infusion"
  • "Active metabolite: 1-hydroxymidazolam (50% activity, renal elimination)"
  • "Metabolism: Hepatic CYP3A4"
  • "Volume of distribution: 0.8-1.5 L/kg"
• ICU Dosing:
  • "Loading: 0.01-0.1 mg/kg IV"
  • "Infusion: 0.02-0.2 mg/kg/hr"
• Accumulation: Prolonged sedation in hepatic dysfunction (reduced metabolism), renal dysfunction (metabolite accumulation), obesity (lipophilic storage), elderly
• Adverse Effects:
  • Delirium (2-3× increased risk vs propofol/dexmedetomidine)
  • Prolonged sedation
  • Respiratory depression
  • Hypotension (mild)
  • Paradoxical agitation
  • Tolerance and withdrawal
• Indications in ICU: Seizures, alcohol withdrawal, refractory agitation, propofol contraindication

Dexmedetomidine

• Class: Imidazole α2-adrenoceptor agonist
• Mechanism: Highly selective α2A-agonist (α2:α1 = 1600:1). Binds locus coeruleus → reduced noradrenergic output → sedation mimicking NREM sleep. Also binds spinal dorsal horn α2 receptors → analgesia.
• Unique Feature: "Cooperative sedation"
• patients arousable to voice, can follow commands, return to sleep. Minimal respiratory depression.
• Pharmacokinetics:
  • "Onset: 5-10 minutes"
  • "Peak effect: 15-30 minutes (with loading dose)"
  • "Elimination half-life: 2-3 hours"
  • "Context-sensitive half-time: 40-60 minutes (minimal accumulation)"
  • "Metabolism: Hepatic glucuronidation (CYP2A6)"
  • No active metabolites
  • "Clearance: 39 L/hr"
• ICU Dosing:
  • "Loading dose: 0.5-1 mcg/kg over 10-20 min (optional, causes hypotension/bradycardia)"
  • "Infusion: 0.2-1.4 mcg/kg/hr (typically 0.2-0.7)"
• Monitoring: HR, BP, ECG (for bradycardia)
• Adverse Effects:
  • Bradycardia (8-30%, especially with loading dose)
  • "Hypotension (loading dose: initial hypertension from α1 effect, then hypotension)"
  • Atrial fibrillation (increased incidence in cardiac surgery)
  • Withdrawal syndrome (rebound hypertension, agitation)
• Advantages:
  • Reduced delirium vs benzodiazepines
  • No respiratory depression (can use for procedural sedation in non-intubated)
  • Opioid-sparing (analgesic properties)
  • Natural sleep architecture preservation
• Contraindications: Hemodynamically unstable (without vasopressor support), severe bradycardia, heart block (without pacing)
• PBS/TGA: PBS Authority required, S4 drug

Ketamine

• Class: Phencyclidine derivative, NMDA receptor antagonist
• Mechanism: Non-competitive antagonist at NMDA glutamate receptor. Also interacts with opioid receptors, monoamine transporters, voltage-gated sodium channels.
• Effects:
  • Dissociative anesthesia (disconnection of thalamus from limbic system)
  • Analgesia (NMDA antagonism, opioid receptor modulation)
  • Bronchodilation (β2-agonist effect, anticholinergic)
  • Sympathetic stimulation (catecholamine reuptake inhibition)
  • Anti-depressant (subanesthetic doses)
• Pharmacokinetics:
  • "Onset: 30-60 seconds IV"
  • "Duration: 10-20 minutes (single dose)"
  • "Elimination half-life: 2-3 hours"
  • "Metabolism: Hepatic CYP3A4, CYP2B6"
  • "Active metabolite: Norketamine (33% activity)"
  • "Context-sensitive half-time: Minimal increase with prolonged infusion"
• ICU Dosing:
  • "Analgesia (adjunct): 0.1-0.3 mg/kg/hr"
  • "Sedation/anesthesia: 0.5-2 mg/kg/hr"
  • "Bolus for procedures: 0.5-1 mg/kg"
• Advantages in ICU:
  • Hemodynamic stability (sympathetic stimulation)
  • Bronchodilation (useful in asthma/COPD)
  • Opioid-sparing (25-50% reduction in opioid requirements)
  • Anti-hyperalgesic (prevents OIH)
  • Reduced PONV with low-dose use
• Adverse Effects:
  • Emergence phenomena (dysphoria, hallucinations, nightmares) - reduced with benzodiazepines
  • Hypertension, tachycardia
  • Hypersalivation
  • Raised ICP (controversial - only in spontaneously breathing patients without ventilation)
  • Nausea
• Cautions: Uncontrolled hypertension, ischemic heart disease, psychiatric history

Pharmacology - Analgesic Agents

Opioids (General Principles)

Mechanism: Agonists at μ (mu), κ (kappa), δ (delta) opioid receptors. Predominantly μ-receptor activation produces analgesia via:

• Presynaptic: Reduced neurotransmitter release (Ca2+ channel inhibition)
• Postsynaptic: K+ channel opening → hyperpolarization
• Descending modulation: Enhanced inhibitory pathways

Common ICU Opioids:

Fentanyl in ICU:

• Dosing: Loading 25-100 mcg, infusion 25-200 mcg/hr
• Advantages: Rapid onset, hemodynamic stability, no histamine release
• Disadvantages: Lipophilic - accumulates in prolonged infusion (context-sensitive half-time increases from 40 min after 2 hr to 300 min after 8 hr)
• Chest wall rigidity: High-dose bolus (>5 mcg/kg rapid) - treat with naloxone or muscle relaxant

Morphine in ICU:

• Dosing: Loading 2-5 mg, infusion 1-5 mg/hr
• Caution: M6G accumulation in renal failure → prolonged sedation, respiratory depression
• Histamine release: May cause hypotension, bronchospasm

Remifentanil in ICU:

• Dosing: 0.025-0.2 mcg/kg/min (no loading dose)
• Advantages: Ultra-short acting (organ-independent metabolism), no accumulation
• Disadvantages: Expensive, acute tolerance, opioid-induced hyperalgesia (OIH), requires continuous infusion
• Use: Short-term analgesia, neurological assessment windows

Paracetamol (Acetaminophen)

• Mechanism: Central COX inhibition, serotonergic descending pathway modulation, possible cannabinoid receptor activation (via AM404 metabolite)
• Dosing: 1g IV/PO q6h (max 4g/day); reduce to 2-3g/day in hepatic dysfunction, chronic alcohol use, malnutrition
• Efficacy: Reduces opioid requirements by 20-30% (PMID: 21343554)
• Cautions: Hepatotoxicity in overdose, dose reduction in liver disease, avoid in acute liver failure

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

• Mechanism: COX-1 and COX-2 inhibition → reduced prostaglandin synthesis
• ICU Use: Limited due to adverse effect profile
• Adverse Effects:
  • Acute kidney injury (prostaglandin-mediated renal vasodilation loss)
  • GI bleeding
  • Platelet dysfunction
  • Cardiovascular events (COX-2 selective)
• Relative Contraindications in ICU: AKI, GI bleeding risk, coagulopathy, cardiac surgery

Regional Analgesia in ICU

Benefits:

• Superior analgesia for chest trauma, abdominal surgery, thoracic surgery
• Reduced opioid requirements (40-60%)
• Improved respiratory mechanics (chest wall pain)
• Possible reduction in chronic pain development

Common ICU Blocks:

Evidence:

• ANZICS trauma guidelines recommend regional analgesia for rib fractures (PMID: 29486912)
• Thoracic epidural reduces respiratory complications in blunt chest trauma (PMID: 16317094)
• Paravertebral block comparable to epidural for rib fractures with fewer side effects (PMID: 26366472)

Contraindications to Neuraxial Analgesia in ICU:

• Coagulopathy (platelets <80, INR >1.5, therapeutic anticoagulation)
• Sepsis/local infection
• Hemodynamic instability (epidural sympathetic block)
• Patient refusal
• Spinal cord compression

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6. Clinical Presentation and Assessment

Pain Assessment

Verbal Patients - Numeric Rating Scale (NRS)

Description: Patient rates pain 0-10 (0 = no pain, 10 = worst imaginable)

Implementation:

• Assess at rest and with movement (coughing, turning)
• Pain ≥4 indicates need for intervention
• Target NRS ≤3-4 for comfort

Non-Verbal Patients - Behavioral Pain Scale (BPS)

Description: Validated for intubated patients unable to self-report (PMID: 11445675)

Interpretation:

• Total score: 3-12
• BPS ≥5: Clinically significant pain requiring treatment
• Sensitivity 63%, Specificity 91% for pain detection

Non-Verbal Patients - Critical Care Pain Observation Tool (CPOT)

Description: Alternative to BPS, validated in surgical and medical ICU populations (PMID: 19542879)

Interpretation:

• Total score: 0-8
• CPOT ≥3: Clinically significant pain
• Sensitivity 86%, Specificity 78%

Sedation Assessment

Richmond Agitation-Sedation Scale (RASS)

Description: Most widely validated sedation scale in ICU (PMID: 12131178)

Assessment Procedure:

1. Observe patient for 30 seconds without stimulation
2. If not alert, call patient's name and ask to open eyes
3. If no response to voice, physically stimulate (shoulder shake or sternal rub)

Scoring (see Table in Key Points section)

Advantages:

• Excellent inter-rater reliability (κ = 0.91)
• Validated against EEG and BIS
• Simple and rapid (10-20 seconds)

Sedation-Agitation Scale (SAS)

Description: Seven-point scale, alternative to RASS (PMID: 10470645)

Target: SAS 3-4 for most patients (equivalent to RASS -2 to 0)

Motor Activity Assessment Scale (MAAS)

Description: Seven-point scale focusing on motor activity (PMID: 10605946)

Target: MAAS 2-4

Delirium Assessment

Confusion Assessment Method for ICU (CAM-ICU)

Description: Validated for ICU delirium detection, 95% sensitivity, 89% specificity (PMID: 11445689)

Assessment:

1. Feature 1: Acute onset or fluctuating course
2. Feature 2: Inattention (LETTERS auditory test or PICTURES)
3. Feature 3: Altered level of consciousness (RASS ≠ 0)
4. Feature 4: Disorganized thinking (simple questions + commands)

Diagnosis: Feature 1 + Feature 2 + (Feature 3 OR Feature 4)

Frequency: At least twice daily (am and pm)

Intensive Care Delirium Screening Checklist (ICDSC)

Description: 8-item checklist, score ≥4 = delirium

Items: Altered consciousness, inattention, disorientation, hallucinations/delusions, psychomotor agitation/retardation, inappropriate speech/mood, sleep/wake disturbance, symptom fluctuation

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7. ICU Management

Initial Assessment and Protocol Initiation

Step 1: Pain Assessment (First Priority)

• Use NRS for verbal patients, BPS or CPOT for non-verbal
• Assess at rest and with movement
• Treat pain if NRS ≥4, BPS ≥5, or CPOT ≥3

Step 2: Sedation Assessment

• Use RASS (preferred) or SAS
• Determine sedation goal based on clinical situation:
  • "Most patients: RASS -2 to 0"
  • "ARDS requiring paralysis: RASS -4 to -5"
  • "Raised ICP: RASS -3 to -5"
  • "Status epilepticus: RASS -4 to -5"
  • "Alcohol withdrawal: RASS -1 to 0 (symptom-triggered)"

Step 3: Delirium Screening

• CAM-ICU or ICDSC twice daily
• If positive, implement delirium management pathway

Analgesia-First Protocol

Principle: Treat pain before sedation - many "agitated" patients are actually in pain.

Step 1: Non-Pharmacological Interventions

• Positioning, pressure area care
• Music therapy
• Family presence
• Noise reduction
• Sleep optimization

Step 2: Regular Paracetamol

• 1g IV/PO q6h (max 4g/day)
• Reduces opioid requirements by 20-30%

Step 3: Opioid Analgesia

• First-line: Fentanyl (hemodynamic stability) or morphine
• Fentanyl infusion: 25-100 mcg/hr (titrate to BPS/CPOT)
• Consider PCA in awake, cooperative patients

Step 4: Adjunctive Analgesia (if opioid requirements high)

• Low-dose ketamine: 0.1-0.3 mg/kg/hr
• Regional analgesia (if appropriate anatomy and no contraindications)
• Avoid NSAIDs in most ICU patients

Sedation Protocol

Indications for Sedation:

• Facilitate mechanical ventilation tolerance
• Reduce metabolic demand (e.g., ARDS, trauma)
• Prevent self-harm (removal of tubes/lines)
• Anxiolysis
• Facilitate procedures
• Manage agitation

First-Line Agents (PADIS 2018 Recommendation):

Short-term (<48h): Propofol

• Start: 0.5-1 mg/kg/hr
• Titrate: 0.5-4 mg/kg/hr to RASS target
• Maximum: 4 mg/kg/hr (PRIS prevention)
• Monitor: Triglycerides q24-48h, lactate

Long-term (>48h) or Delirium Risk: Dexmedetomidine

• Optional loading: 0.5 mcg/kg over 10-20 min (causes hypotension/bradycardia)
• Infusion: 0.2-0.7 mcg/kg/hr (max 1.4 mcg/kg/hr)
• Advantages: Reduced delirium, cooperative sedation

Second-Line (Specific Indications): Midazolam

• Indications: Seizures, alcohol withdrawal, propofol/dexmedetomidine contraindicated
• Loading: 0.01-0.05 mg/kg
• Infusion: 0.02-0.1 mg/kg/hr
• Monitor for accumulation (especially hepatic/renal dysfunction)

Daily Sedation Interruption (DSI) Protocol

Evidence Base:

• Kress 2000 (PMID: 10816189): DSI reduced mechanical ventilation by 2.4 days, ICU LOS by 3.5 days
• Girard ABC Trial (PMID: 18431285): Combined SAT+SBT reduced mortality (HR 0.68), ICU LOS, ventilator days

Protocol:

Daily Assessment (0600-0800):

1. Screen for contraindications
2. If no contraindications, stop sedation infusion
3. Wait 30-60 minutes

Awakening Trial Endpoints (restart sedation at 50% dose):

• Agitation (RASS +2 or greater)
• Anxiety/distress
• Sustained SpO2 <88%
• RR >35/min for >5 min
• Acute cardiac arrhythmia
• Signs of increased ICP
• Patient request

Contraindications to DSI:

• Receiving neuromuscular blockade
• Active seizures or status epilepticus
• Severe alcohol withdrawal
• Severe acute respiratory failure (P/F <100, high PEEP >15)
• Agitation requiring escalating sedation
• Raised ICP requiring sedation
• Open abdomen
• Active myocardial ischemia
• Therapeutic hypothermia protocol

If Awakening Trial Passed:

• Proceed to Spontaneous Breathing Trial (SBT)
• Reduce sedation target to RASS 0

ABCDEF Bundle Implementation

A - Assess, Prevent, and Manage Pain:

• BPS/CPOT assessment q4h
• Target BPS <5, CPOT <3
• Analgesia-first approach

B - Both SAT and SBT:

• Daily SAT unless contraindicated
• Proceed to SBT within 1 hour of SAT pass
• SBT: 30-120 min on minimal support (PS 5-8, PEEP 5)

C - Choice of Analgesia and Sedation:

• Avoid benzodiazepines first-line
• Propofol or dexmedetomidine preferred
• Light sedation target (RASS -2 to 0)
• Opioid-sparing strategies

D - Delirium: Assess, Prevent, and Manage:

• CAM-ICU twice daily
• Prevention: Light sedation, early mobilization, sleep hygiene, reorientation
• Treatment: Treat reversible causes, avoid antipsychotics routinely (MIND-USA trial negative)

E - Early Mobility and Exercise:

• Mobilization from Day 1 if hemodynamically stable
• Progressive mobility protocol (in-bed, sitting, standing, walking)
• Evidence: Reduced delirium, improved functional outcomes (PMID: 25608884)

F - Family Engagement and Empowerment:

• Open visiting hours
• Family participation in care
• Shared decision-making
• ICU diary provision

Special Populations

Indigenous Health Considerations

Aboriginal and Torres Strait Islander Patients:

• Cultural Safety: Involve Aboriginal Health Worker (AHW) or Aboriginal Liaison Officer (ALO) in care planning
• Pain Assessment: May underreport pain due to cultural factors; use behavioral scales liberally
• Communication: Ensure appropriate interpreter services; avoid assuming English proficiency
• Family Involvement: Extended family decision-making common; allow for larger family meetings
• Spiritual Care: Respect for Country and cultural protocols; liaise with cultural liaison services
• Discharge Planning: Consider remote community access to follow-up; involve community health services early

Māori Patients:

• Whānau Involvement: Extended family central to decision-making
• Te Whare Tapa Whā Model: Address all four dimensions - tinana (physical), hinengaro (mental), wairua (spiritual), whānau (family)
• Cultural Protocols: Karakia (prayers) may be important for family; respect tapu (sacred) and noa (ordinary)
• Māori Health Workers: Involve early for cultural liaison

Obesity

• Pharmacokinetics: Increased Vd for lipophilic drugs (propofol, fentanyl, midazolam)
• Dosing:
  • "Propofol: Use LBW for induction, TBW for infusion maintenance"
  • "Fentanyl: Use LBW or IBW (accumulation concern)"
  • "Dexmedetomidine: Use IBW"
  • "Midazolam: Use IBW (accumulation in fat)"
• Monitoring: More frequent assessment; context-sensitive half-time prolonged
• PRIS Risk: Higher in obesity; limit propofol to <4 mg/kg/hr (based on TBW)

Renal Dysfunction

• Morphine: Avoid - M6G accumulation causes prolonged sedation/respiratory depression
• Midazolam: Accumulation of 1-hydroxymidazolam; reduce dose, use intermittent boluses
• Fentanyl: Preferred opioid; no significant active metabolites
• Propofol/Dexmedetomidine: No dose adjustment required
• Paracetamol: No dose adjustment required

Hepatic Dysfunction

• Midazolam: Significantly prolonged half-life; reduce dose 50%+
• Fentanyl: Reduced clearance; reduce dose by 50%
• Propofol: Reduced clearance; use lower maintenance doses
• Dexmedetomidine: Reduce dose; hepatic metabolism
• Paracetamol: Reduce to 2-3g/day maximum

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8. Monitoring & Complications

Monitoring Parameters

Pain Monitoring:

• BPS/CPOT: q4h and before/after painful procedures
• Document trends and response to interventions

Sedation Monitoring:

• RASS: q1-2h during titration, q4h when stable
• Target documented and reviewed daily
• Assess for over/under-sedation

Delirium Monitoring:

• CAM-ICU: Twice daily (am and pm)
• ICDSC: Alternative, once daily minimum

Drug-Specific Monitoring:

• Propofol: Triglycerides q24-48h, CK if prolonged, lactate daily
• Dexmedetomidine: HR, BP continuous; ECG for bradycardia
• Opioids: Respiratory rate, pupil size, bowel function
• Midazolam: Watch for accumulation in renal/hepatic dysfunction

Complications

Oversedation

Definition: RASS -4 to -5 when not indicated or RASS deeper than target

Consequences:

• Increased mortality (10% per RASS point below -2)
• Prolonged mechanical ventilation (2-4 additional days)
• Increased delirium incidence
• ICU-acquired weakness
• Delayed functional recovery
• Increased healthcare costs

Prevention:

• Protocol-driven sedation with light targets
• Daily sedation interruption
• Regular RASS assessment
• Nurse-driven titration protocols

Undersedation/Agitation

Definition: RASS +1 to +4 or failure to tolerate ventilator

Consequences:

• Self-extubation (5-15% of ventilated patients)
• Line removal
• Patient injury, falls
• Staff injury
• Increased sympathetic stress response
• PTSD risk

Management:

• Assess and treat pain first
• Identify reversible causes (hypoxia, hypoglycemia, urinary retention, constipation)
• Exclude organic causes (sepsis, withdrawal, stroke)
• Optimize sedation agent and dose

Delirium

Incidence: 50-80% of ventilated ICU patients

Risk Factors:

• Deep sedation (RASS ≤-3)
• Benzodiazepine use
• Age >65
• Pre-existing cognitive impairment
• Alcohol/substance use
• Sepsis, metabolic derangements

Subtypes:

• Hyperactive (5%): Agitation, restlessness, hallucinations
• Hypoactive (45%): Withdrawn, flat affect, inattention - easily missed
• Mixed (50%): Fluctuates between states

Management:

• Non-pharmacological interventions first (reorientation, sleep hygiene, early mobilization, hearing aids/glasses)
• Avoid deliriogenic drugs (benzodiazepines, anticholinergics)
• Treat reversible causes
• Pharmacological: Antipsychotics NOT routinely recommended (MIND-USA trial, PMID: 30346242)

Withdrawal Syndromes

Risk Factors: Prolonged sedation (>5-7 days), high doses, abrupt cessation

Opioid Withdrawal:

• Features: Agitation, mydriasis, piloerection, diarrhea, tachycardia, hypertension
• Prevention: Taper by 10-20% per day
• Treatment: Methadone, clonidine

Benzodiazepine Withdrawal:

• Features: Anxiety, tremor, seizures, autonomic instability
• Prevention: Gradual taper over 3-7 days
• Treatment: Diazepam (long half-life), clonidine for autonomic symptoms

Dexmedetomidine Withdrawal:

• Features: Hypertension, tachycardia, agitation
• Prevention: Gradual taper
• Incidence: Less than benzodiazepines

ICU-Acquired Weakness (ICUAW)

Association with Sedation: Deep sedation prevents early mobilization, contributes to neuromuscular dysfunction

Prevention:

• Light sedation allowing patient participation
• Early mobilization from Day 1
• Minimize neuromuscular blockade
• Avoid aminoglycosides if possible

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9. Prognosis & Outcomes

Mortality

Deep Sedation Impact (PMID: 22016520):

• Each RASS point below -2: 10% increase in mortality
• RASS -4/-5 vs RASS -2/0: ~30% relative increase in mortality

Delirium Impact:

• ICU delirium: 2-3× increased mortality
• Each additional delirium day: 10% increase in mortality

Morbidity

Ventilator Days:

• Light sedation: 2-4 fewer ventilator days vs deep sedation
• SAT+SBT: 2.4 fewer ventilator days (Kress)

ICU Length of Stay:

• Light sedation: 1-2 fewer days per RASS point toward 0
• SAT+SBT: 3.5 fewer ICU days (Kress)

Long-Term Outcomes (PICS - Post-Intensive Care Syndrome):

• Cognitive impairment: 30-50% at 1 year
• PTSD: 10-20%
• Depression: 20-30%
• Physical weakness: 25-50%

Prognostic Factors

Good Prognostic Factors:

• Light sedation achieved early
• Early mobilization
• Minimal delirium duration
• Younger age
• Lower illness severity (APACHE II)

Poor Prognostic Factors:

• Prolonged deep sedation (>7 days)
• High cumulative benzodiazepine dose
• Prolonged delirium
• ICU-acquired weakness
• Prolonged mechanical ventilation

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10. Landmark Trials and Evidence

Kress Daily Sedation Interruption (2000)

Reference: Kress JP et al. N Engl J Med. 2000;342:1471-7. PMID: 10816189

Design: Single-center RCT, N=128 mechanically ventilated adults

Intervention: Daily sedation interruption until awake vs. usual care

Results:

• Mechanical ventilation: 4.9 vs 7.3 days (p=0.004)
• ICU LOS: 6.4 vs 9.9 days (p=0.02)
• No difference in adverse events

Impact: Established DSI as standard of care

SLEAP ABC Trial (2008)

Reference: Girard TD et al. Lancet. 2008;371:126-34. PMID: 18191684

Design: Multi-center RCT, N=336 mechanically ventilated adults

Intervention: Paired SAT+SBT vs SBT alone

Results:

• Ventilator-free days: 14.7 vs 11.6 (p=0.02)
• 1-year mortality: 44% vs 56% (HR 0.68, p=0.01)
• Delirium-free days: 2.5 more (p<0.001)

Impact: Demonstrated mortality benefit of coordinated SAT+SBT

SPICE III (2019)

Reference: Shehabi Y et al. N Engl J Med. 2019;380:2506-17. PMID: 30576417

Design: Multi-center RCT, N=4000 mechanically ventilated adults (Australia/NZ-led)

Intervention: Early dexmedetomidine-based sedation vs usual care

Results:

• 90-day mortality: 29.1% vs 29.1% (RR 1.0, p=0.98)
• Ventilator-free days: No difference
• Coma-free days: No difference
• More bradycardia and hypotension with dexmedetomidine

Impact: Dexmedetomidine safe but no mortality benefit; light sedation achievable with various agents

MENDS Trial (2007)

Reference: Pandharipande PP et al. JAMA. 2007;298:2644-53. PMID: 18073360

Design: Double-blind RCT, N=106 mechanically ventilated adults

Intervention: Dexmedetomidine vs lorazepam for sedation

Results:

• Delirium-free days: 7.0 vs 3.0 (p=0.01)
• Coma-free days: 9.6 vs 4.9 (p=0.003)
• No mortality difference

Impact: Demonstrated dexmedetomidine reduces delirium vs benzodiazepines

MENDS2 Trial (2021)

Reference: Hughes CG et al. N Engl J Med. 2021;384:1424-36. PMID: 33755045

Design: Multi-center RCT, N=432 adults with sepsis

Intervention: Dexmedetomidine vs propofol for sedation

Results:

• Delirium-free days: No difference (10.7 vs 10.8)
• 90-day mortality: No difference (38% vs 39%)
• Ventilator-free days: No difference

Impact: Dexmedetomidine and propofol equivalent in sepsis for delirium prevention

DahLIA Trial (2016)

Reference: Reade MC et al. Am J Respir Crit Care Med. 2016;194:285-94. PMID: 27372735

Design: Multi-center RCT, N=74 adults with delirium (Australia/NZ-led)

Intervention: Dexmedetomidine vs placebo for ICU delirium resolution

Results:

• Delirium resolution: HR 1.58 (p=0.05)
• Ventilator-free hours: 144 vs 127 (p=0.01)
• More bradycardia with dexmedetomidine

Impact: Dexmedetomidine may hasten delirium resolution

PADIS Guidelines 2018

Reference: Devlin JW et al. Crit Care Med. 2018;46:e825-e873. PMID: 30113379

Key Recommendations:

• Assess pain using valid tools (BPS, CPOT)
• Analgesia-first approach
• Light sedation (RASS -2 to 0)
• Daily sedation interruption
• Avoid benzodiazepines first-line
• Monitor for delirium (CAM-ICU) twice daily
• Early mobilization
• Non-pharmacological delirium prevention

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11. SAQ Practice

SAQ 1: Agitated Ventilated Patient

Time Allocation: 10 minutes
Total Marks: 20

Stem: A 58-year-old male is on Day 2 of mechanical ventilation for community-acquired pneumonia in the ICU. He was previously on midazolam 5 mg/hr and fentanyl 100 mcg/hr. The nurse calls you because he is pulling at his endotracheal tube and fighting the ventilator. His RASS is +2.

Observations:

• HR: 118 bpm
• BP: 165/95 mmHg
• RR: 28/min (set RR 16)
• SpO2: 92% on FiO2 0.5
• Temperature: 37.8°C

Question 1.1 (8 marks)

Outline your systematic approach to assessing and managing this patient's agitation.

Question 1.2 (6 marks)

Discuss the advantages and disadvantages of three sedative agents you might use in this patient.

Question 1.3 (6 marks)

The patient stabilizes overnight but on Day 5 you note he is deeply sedated (RASS -4) on midazolam 8 mg/hr, has a new rise in creatinine from 85 to 220 μmol/L, and has an unexplained metabolic acidosis. Discuss your concerns and management.

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Model Answer - SAQ 1

Question 1.1 (8 marks)

Immediate Assessment - ABCDE Approach (2 marks):

• Airway: Confirm ETT in place, check cuff pressure, exclude displacement
• Breathing: Auscultate for pneumothorax, bronchospasm; check ventilator alarms for high pressures; ensure adequate oxygenation
• Circulation: Exclude hypotension/hypertension, arrhythmia, hemorrhage
• Disability: Assess for pain (BPS/CPOT), exclude hypoglycemia, stroke

Pain Assessment (2 marks):

• Use Behavioral Pain Scale (BPS) since patient is non-verbal
• Score facial expression, upper limb movement, ventilator compliance
• BPS ≥5 indicates significant pain requiring analgesia before sedation adjustment

Reversible Causes Checklist (2 marks):

• Hypoxia (check SpO2, ABG)
• Urinary retention (check bladder volume, insert/flush IDC)
• Constipation (examine abdomen, check bowel chart)
• Full stomach (check gastric residual volumes)
• Uncomfortable positioning
• Noise, light, environmental factors
• Alcohol/benzodiazepine withdrawal

Management (2 marks):

• Treat pain first: Bolus fentanyl 25-50 mcg, increase infusion if ongoing pain
• If still agitated: Propofol bolus 20-40 mg, consider changing to propofol infusion
• Reassess in 15-30 min with RASS scoring
• Set sedation target (likely RASS -2 to 0 for this patient)
• Investigate causes: Consider CT brain if neurological deterioration, septic screen if febrile

Question 1.2 (6 marks)

Question 1.3 (6 marks)

Concerns (3 marks):

• Midazolam accumulation due to AKI: 1-hydroxymidazolam (active metabolite) is renally cleared, accumulates in renal dysfunction
• Unexplained metabolic acidosis: Consider PRIS if propofol was used (check if recently switched), sepsis, lactic acidosis, AKI itself
• Over-sedation: RASS -4 exceeds appropriate target for pneumonia; prolonged sedation increases delirium, ventilator days, mortality
• AKI etiology: Drug-induced (nephrotoxins), sepsis, hypovolemia, obstruction

Management (3 marks):

• Reduce midazolam significantly or switch agent (e.g., to propofol or dexmedetomidine)
• Investigate AKI: Urinalysis, renal ultrasound, review nephrotoxins, optimize volume status
• Address metabolic acidosis: ABG with lactate, check anion gap, septic screen
• Lighten sedation target: Aim RASS -2 to 0 with daily sedation interruption
• Consider transition to intermittent bolus sedation rather than continuous infusion
• Document plan for weaning sedation

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SAQ 2: Propofol Infusion Syndrome

Time Allocation: 10 minutes
Total Marks: 20

Stem: A 45-year-old male is on Day 6 of ICU admission for severe traumatic brain injury (GCS 6T on admission). He required decompressive craniectomy Day 1 and has been sedated for ICP control. Current sedation is propofol 5 mg/kg/hr and fentanyl 150 mcg/hr. He is also on noradrenaline 0.2 mcg/kg/min.

Overnight he developed:

• New-onset bradycardia (HR 45 bpm)
• Metabolic acidosis (pH 7.22, lactate 6.5 mmol/L)
• Triglycerides 8.5 mmol/L (previous 2.1)
• CK 18,500 U/L (previous 850)

Question 2.1 (8 marks)

Discuss your differential diagnosis and the most likely diagnosis in this clinical context.

Question 2.2 (6 marks)

Outline your immediate management of this condition.

Question 2.3 (6 marks)

Discuss strategies to prevent this complication in ICU patients requiring prolonged sedation.

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Model Answer - SAQ 2

Question 2.1 (8 marks)

Most Likely Diagnosis: Propofol Infusion Syndrome (PRIS) (4 marks):

• Classic pentad present: Metabolic acidosis + rhabdomyolysis (CK 18,500) + hyperlipidemia (TG 8.5) + bradyarrhythmia + cardiac dysfunction (hypotension requiring vasopressors)
• High-risk scenario: Propofol 5 mg/kg/hr (exceeds 4 mg/kg/hr threshold), duration 6 days (exceeds 48h), catecholamine infusion, young male, TBI (catecholamine surge)
• Pathophysiology: Impaired mitochondrial fatty acid oxidation, uncoupling of oxidative phosphorylation, mitochondrial respiratory chain dysfunction

Differential Diagnosis (4 marks):

• Sepsis: Could cause metabolic acidosis, tachycardia (not bradycardia), elevated lactate; rhabdomyolysis less typical
• Seizures (NCSE): Could explain metabolic acidosis and rhabdomyolysis in TBI patient; would expect tachycardia not bradycardia
• Acute coronary syndrome: Could cause bradycardia, elevated CK; but CK this high more consistent with rhabdomyolysis; would check troponin
• Medication toxicity (other): Review all medications; fentanyl toxicity less likely with this picture
• Refeeding syndrome: Could cause metabolic disturbance; check phosphate, magnesium, potassium
• Malignant hyperthermia: Unlikely without volatile anesthetics/succinylcholine

Question 2.2 (6 marks)

Immediate Management (6 marks):

1. Stop propofol immediately (2 marks) - Critical first step; switch to alternative sedation

2. Alternative sedation for ICP control (1 mark):

   • Midazolam 0.05-0.2 mg/kg/hr
   • Consider dexmedetomidine if hemodynamically tolerant (caution with bradycardia)
   • Maintain ICP <22 mmHg target

3. Cardiovascular support (1 mark):

   • Treat bradycardia: Atropine if symptomatic, consider pacing if refractory
   • Inotropic support: May need switch from noradrenaline to adrenaline or dobutamine
   • Prepare for cardiac arrest (PRIS mortality 33-80%)

4. Metabolic correction (1 mark):

   • Treat metabolic acidosis: Supportive, consider RRT if severe (pH <7.1)
   • Manage rhabdomyolysis: Aggressive IV fluids, target UO 200-300 mL/hr, consider RRT for myoglobinuria/AKI
   • Lipid management: Supportive; TG will fall after propofol cessation

5. Investigations and monitoring (1 mark):

   • Serial ABG/VBG for lactate clearance
   • Serial CK, troponin, electrolytes
   • ECG and continuous cardiac monitoring
   • Consider ECMO if refractory cardiac failure

Question 2.3 (6 marks)

Prevention Strategies (6 marks):

1. Dose limitation (2 marks):

   • Maximum propofol 4 mg/kg/hr
   • Maximum duration 48-72 hours at high doses
   • Consider alternative agents if higher doses needed

2. Monitoring (2 marks):

   • Daily triglycerides (aim <5 mmol/L)
   • CK at baseline and if prolonged use (q48-72h)
   • Daily lactate
   • ECG monitoring
   • Maintain carbohydrate intake (reduces reliance on fatty acid oxidation)

3. Risk factor modification (1 mark):

   • Minimize catecholamine infusions if possible
   • Adequate nutrition (6-8 g/kg/day carbohydrate)
   • Consider propofol-sparing regimens (multimodal sedation)

4. Alternative sedation strategies (1 mark):

   • Early transition to dexmedetomidine
   • Low-dose ketamine as adjunct
   • Midazolam when propofol limits reached
   • Regular sedation breaks/DSI when ICP allows

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12. Viva Scenarios

Viva 1: PADIS Guidelines and Evidence

Stem: "A new ICU registrar asks you about the evidence behind our sedation protocols. Please explain the PADIS guidelines and the key evidence supporting them."

Duration: 12 minutes (2 min reading + 10 min discussion)

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Opening Question: "What are the PADIS guidelines and what are the key recommendations?"

Expected Answer (3 minutes):

"PADIS stands for Pain, Agitation/sedation, Delirium, Immobility, and Sleep disruption. These are the 2018 Society of Critical Care Medicine guidelines, published in Critical Care Medicine. They replace the previous PAD guidelines from 2013.

Key Recommendations:

Pain:

• Use validated pain assessment tools: NRS for verbal patients, BPS or CPOT for non-verbal
• Analgesia-first approach before sedation
• Multimodal analgesia to reduce opioid requirements

Agitation/Sedation:

• Light sedation targeting RASS -2 to 0 for most patients
• Avoid benzodiazepines as first-line; prefer propofol or dexmedetomidine
• Daily sedation interruption when appropriate
• Protocol-driven sedation management

Delirium:

• Routine screening with CAM-ICU or ICDSC twice daily
• Non-pharmacological prevention strategies
• Antipsychotics NOT routinely recommended for treatment (MIND-USA trial negative)

Immobility:

• Early mobilization from Day 1 when safe
• Reduces delirium and improves functional outcomes

Sleep:

• Promote sleep hygiene: reduce noise, cluster care, dim lights at night
• Consider sleep protocols

---

Follow-up Question 1: "What is the evidence for light sedation?"

Expected Answer (2-3 minutes):

"Multiple trials demonstrate benefit from light sedation:

Kress 2000: Landmark trial showing daily sedation interruption reduced ventilator days by 2.4 days and ICU LOS by 3.5 days. No increase in adverse events.

Girard ABC Trial 2008: Paired SAT+SBT versus SBT alone. Demonstrated 12% absolute mortality reduction at 1 year (44% vs 56%), plus reduced ventilator and ICU days. This was the first trial to show mortality benefit.

SLEAP/ABC Collaborative 2012: Confirmed that deeper sedation (RASS -3 to -5) associated with increased mortality - approximately 10% increase per RASS point below -2.

Mechanism: Light sedation allows earlier spontaneous breathing trials, reduces delirium, enables earlier mobilization, and may reduce catecholamine stress response.

However, some patients require deep sedation: severe ARDS with prone positioning, paralysis, raised ICP, status epilepticus. The key is appropriate targeting for individual patients."

---

Follow-up Question 2: "What is the role of dexmedetomidine and the evidence supporting it?"

Expected Answer (2-3 minutes):

"Dexmedetomidine is a selective alpha-2 agonist with unique properties - it produces 'cooperative sedation' where patients are arousable yet calm, mimicking natural sleep via locus coeruleus inhibition.

Evidence:

MENDS 2007: Dexmedetomidine vs lorazepam showed more delirium-free and coma-free days with dexmedetomidine. This established superiority over benzodiazepines.

MENDS2 2021: Dexmedetomidine vs propofol in sepsis showed NO difference in delirium-free days or mortality. So dexmedetomidine is non-inferior to propofol.

SPICE III 2019: Large Australian/NZ trial (4000 patients). Early dexmedetomidine vs usual care showed NO mortality difference. 90-day mortality identical at 29.1%. More bradycardia and hypotension with dexmedetomidine.

DahLIA 2016: Australian trial showing dexmedetomidine may hasten delirium resolution in established delirium.

Bottom Line: Dexmedetomidine reduces delirium compared to benzodiazepines but has no proven advantage over propofol. Choice depends on patient factors - dexmedetomidine preferred if delirium risk high, propofol if need for rapid titration or deeper sedation."

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Follow-up Question 3: "How would you apply these guidelines in an Aboriginal patient from a remote community?"

Expected Answer (2 minutes):

"Indigenous patients require additional considerations:

Cultural Safety:

• Involve Aboriginal Health Worker or Aboriginal Liaison Officer early
• Recognize that pain may be underreported due to cultural factors - use behavioral scales liberally
• Extended family central to decision-making - allow for larger family meetings

Clinical Considerations:

• Higher rates of hepatorenal disease affecting drug metabolism
• Consider dose adjustments for sedatives with hepatic/renal clearance
• Higher rates of chronic pain conditions - may have opioid tolerance

Communication:

• Ensure interpreter services if needed
• Allow time for discussions; avoid rushing decisions
• Respect for Country and cultural protocols important

Discharge Planning:

• Remote communities have limited follow-up access
• Involve community health services early
• Consider retrieval implications if complications develop

These principles align with the Health Advocate domain of CICM curriculum - addressing vulnerable populations."

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Viva 2: Pain Assessment in Non-Verbal Patients

Stem: "A nursing colleague asks you to review their pain assessment protocol for ventilated patients who cannot communicate. Please discuss the validated tools and your approach."

Duration: 12 minutes

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Opening Question: "What validated tools are available for pain assessment in non-verbal ICU patients?"

Expected Answer (3 minutes):

"The PADIS guidelines recommend either the Behavioral Pain Scale (BPS) or Critical Care Pain Observation Tool (CPOT) for non-verbal patients.

Behavioral Pain Scale (BPS):

• Three domains: Facial expression, upper limb movement, ventilator compliance
• Score range 3-12 (each domain 1-4)
• BPS ≥5 indicates clinically significant pain
• Sensitivity 63%, specificity 91%
• Originally validated by Payen in 2001

Critical Care Pain Observation Tool (CPOT):

• Four domains: Facial expression, body movements, muscle tension, ventilator compliance (or vocalization if extubated)
• Score range 0-8 (each domain 0-2)
• CPOT ≥3 indicates clinically significant pain
• Sensitivity 86%, specificity 78%
• Validated by Gelinas in 2006

Advantages of BPS: Simpler, widely used Advantages of CPOT: Higher sensitivity, includes muscle tension assessment

Either tool is acceptable; the key is consistent use and documentation of trends."

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Follow-up Question: "How do you assess pain when the patient is deeply sedated?"

Expected Answer (2-3 minutes):

"This is challenging because behavioral indicators are attenuated in deep sedation.

Approach:

1. Observe during painful procedures: Dressing changes, turning, suctioning. Even deeply sedated patients may show autonomic (tachycardia, hypertension, pupil dilation) or behavioral (grimacing, movement) responses to painful stimuli.

2. Physiological indicators (supportive but not diagnostic):

   • Tachycardia, hypertension may indicate pain
   • Pupil dilation
   • Diaphoresis
   • However, these are non-specific - also occur with sepsis, hypercarbia, agitation

3. Analgesia trial: If unclear, trial of opioid analgesia and observe for:

   • Reduction in autonomic signs
   • Improved ventilator synchrony
   • Reduction in sedation requirement

4. Assume pain in high-risk situations:

   • Post-operative patients
   • Trauma patients
   • Procedures being performed
   • Known painful conditions

5. Document and reassess: Frequent reassessment as sedation lightens; reassess with each shift change."

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Follow-up Question: "What are the barriers to adequate pain assessment and treatment in ICU?"

Expected Answer (2 minutes):

"Multiple barriers exist at patient, clinician, and system levels:

Patient Barriers:

• Inability to communicate (intubation, cognitive impairment)
• Altered level of consciousness
• Cultural factors affecting pain expression
• Fear of addiction (opioid concerns)

Clinician Barriers:

• Lack of training in validated tools
• Time constraints
• Concern about respiratory depression from opioids
• Misinterpreting pain as agitation and increasing sedation
• Underappreciation of pain in certain populations (elderly, cognitively impaired)

System Barriers:

• Lack of protocolized pain assessment
• Infrequent documentation requirements
• No mandatory pain scoring
• Limited access to multimodal analgesia options

Solutions:

• Mandatory regular pain scoring (q4h minimum)
• Nurse-driven analgesia protocols
• Education on validated tools
• Quality improvement initiatives tracking pain scores
• Multimodal analgesia protocols to reduce opioid reliance"