Sedation in icu

Surgical approach (if applicable)

Not an operation: sedation in ICU supports organ support (ventilation, procedures, comfort, safety) rather than a surgical technique.
Procedures commonly requiring ICU sedation/analgesia
- Endotracheal intubation / tracheostomy care, bronchoscopy, chest drain insertion, central/arterial lines, wound care/dressings, imaging/transfer.

Anaesthetic management (ICU sedation context)

Type of anaesthesia: ICU sedation/analgesia (not GA), titrated to a sedation target; may require GA-level hypnosis for specific procedures (e.g., bronchoscopy) or neuromuscular blockade in selected cases.
Airway: often already intubated/tracheostomy; if not, plan airway strategy for procedures/transfer (oxygenation, aspiration risk, rescue plan).
Duration: hours to days; aim for the lightest effective sedation with daily review and sedation breaks where appropriate.
How painful: sedation ≠ analgesia; many ICU stressors are painful (ETT, suction, drains, wounds). Prioritise analgesia-first strategies.

Aims and principles

Provide comfort, anxiolysis and ventilator synchrony while enabling early mobilisation, neurological assessment and weaning.
Use protocolised sedation with a defined target (e.g., RASS) and frequent reassessment.
Analgesia-first sedation: treat pain before escalating hypnotics.
Minimise benzodiazepines; avoid deep sedation unless specific indication (e.g., refractory hypoxaemia, raised ICP, status epilepticus).
Daily sedation interruption / sedation hold and spontaneous breathing trials when safe.

Indications for sedation in ICU

Mechanical ventilation: tolerance of ETT, ventilator synchrony, prevention of self-extubation.
Procedures: bronchoscopy, line insertion, imaging/transfer.
Control of agitation/delirium (after reversible causes addressed).
Specific indications for deeper sedation: severe ARDS (including proning), neuromuscular blockade, raised ICP, therapeutic hypothermia/TTM, status epilepticus.

Sedation targets and assessment tools

Set a target level and document regularly (at least 4-hourly; more frequently during titration).
RASS (Richmond Agitation–Sedation Scale): +4 combative to −5 unarousable; common target for ventilated patients is 0 to −2 unless specific indication for deeper sedation.
SAS (Sedation–Agitation Scale) as alternative.
Pain assessment: self-report if possible; otherwise behavioural tools (e.g., BPS/CPOT).
Delirium screening: CAM-ICU or ICDSC; treat contributors and use non-pharmacological measures first-line.
Depth of sedation monitoring (EEG-based e.g., BIS) is not routine; consider when neuromuscular blockade, refractory seizures, or concern about awareness with paralysis.

Drug options: key properties and exam-relevant comparisons

Propofol (infusion)
- Pros: rapid onset/offset; easy titration; antiemetic; reduces ICP/CMRO2 (useful in neuro).
- Cons: hypotension (vasodilation, myocardial depression); hypertriglyceridaemia; pancreatitis; no analgesia; risk of Propofol Infusion Syndrome (PRIS).
- PRIS risk factors: high dose and prolonged infusion, critical illness (sepsis), catecholamines, steroids, low carbohydrate states; features include metabolic acidosis, rhabdomyolysis, renal failure, hyperkalaemia, cardiac failure/arrhythmias.
Dexmedetomidine (alpha-2 agonist)
- Pros: cooperative/rousable sedation; minimal respiratory depression; may reduce delirium and facilitate extubation; opioid-sparing.
- Cons: bradycardia, hypotension (and sometimes hypertension with loading); limited depth—may be insufficient alone for severe agitation/ARDS; cost.
Opioids (analgesia-first): fentanyl/alfentanil/remifentanil/morphine
- Use to treat pain and ventilator intolerance; combine with light hypnotic if needed.
- Fentanyl: haemodynamically stable; accumulation with prolonged infusion (context-sensitive half-time increases).
- Remifentanil: very short context-sensitive half-time; useful for rapid wake-up/extubation; risk of acute tolerance/hyperalgesia; requires alternative analgesia plan.
- Morphine: histamine release (hypotension), active metabolites (M6G) accumulate in renal failure; slower offset.
- All opioids: respiratory depression (less relevant if ventilated but important during weaning), ileus, urinary retention, immunomodulation, delirium contribution.
Benzodiazepines (midazolam/lorazepam)
- Role: seizures, alcohol/benzo withdrawal, short-term sedation when others unsuitable.
- Cons: delirium association, prolonged sedation (accumulation esp. with midazolam), respiratory depression, hypotension (less than propofol), tolerance/withdrawal.
- Midazolam: lipophilic; context-sensitive half-time increases markedly with prolonged infusion; active metabolite (1-hydroxymidazolam) accumulates in renal failure.
Ketamine (adjunct)
- Pros: analgesia, opioid-sparing; maintains airway reflexes/resp drive (dose-dependent); bronchodilation; useful in opioid-tolerant patients.
- Cons: sympathetic stimulation (tachycardia, hypertension), sialorrhoea, emergence phenomena; caution in severe coronary disease; consider impact on ICP (evidence suggests safe with controlled ventilation, but exam answer: caution in raised ICP).
Antipsychotics (for delirium/agitation): haloperidol, atypicals
- Use for distressing agitation or risk to staff/patient after addressing causes; not for routine delirium prevention.
- Risks: QT prolongation/torsades, extrapyramidal effects, NMS (rare). Monitor ECG and electrolytes (K, Mg).

Non-pharmacological measures (high-yield)

Treat reversible causes of agitation: pain, hypoxia, hypercapnia, hypotension, hypoglycaemia, withdrawal, urinary retention, constipation, sepsis, environmental stress.
Sleep and orientation: day–night cues, reduce noise/light overnight, hearing aids/glasses, regular reorientation, family engagement where appropriate.
Early mobilisation and physiotherapy; minimise restraints and lines where possible.

Ventilation, weaning and sedation holds

Daily sedation interruption (if safe) reduces duration of ventilation and ICU length of stay when combined with protocolised care.
Coordinate with spontaneous breathing trials; aim for awake, comfortable, cooperative patient for extubation (often RASS −1 to 0).
Avoid over-sedation: delays weaning, increases delirium, increases VAP risk and ICU-acquired weakness (via immobility).

Special situations

Neurocritical care (raised ICP/brain injury)
- Need reliable neuro exams: prefer short-acting, titratable agents; avoid prolonged benzos.
- Propofol reduces ICP/CMRO2 but watch hypotension (maintain CPP).
ARDS/proning/NMB
- May require deeper sedation to tolerate ventilation strategies and paralysis; ensure analgesia and consider EEG-based monitoring if paralysed.
Renal/hepatic failure
- Avoid accumulation: midazolam and morphine metabolites accumulate in renal failure; consider propofol/dexmedetomidine/remifentanil with careful haemodynamic monitoring.
Alcohol/benzodiazepine withdrawal
- Benzodiazepines are first-line; consider adjuncts (e.g., clonidine/dexmedetomidine) for sympathetic overactivity; give thiamine and correct electrolytes (Mg, PO4).

Monitoring and safety

Minimum: ECG, SpO2, NIBP/arterial line, capnography if ventilated, temperature, urine output; regular sedation/pain/delirium scoring.
Drug-specific monitoring: triglycerides/CK/lactate for prolonged propofol; ECG QT for antipsychotics; bradycardia/hypotension for dexmedetomidine.
Prevent complications: DVT prophylaxis, pressure area care, eye care (especially if paralysed), mouth care, stress ulcer prophylaxis when indicated.

Delirium: approach (very examinable)

Definition: acute fluctuating disturbance of attention/awareness with cognitive change; hyperactive, hypoactive or mixed.
Risk factors: age, dementia, sepsis, organ failure, hypoxia, sleep deprivation, benzodiazepines, alcohol withdrawal, pain, immobility.
Management: identify/treat causes (infection, hypoxia, metabolic), optimise analgesia, reduce/stop deliriogenic drugs, non-pharmacological bundle (sleep, reorientation, mobilisation).
Drug therapy: only if severe distress or danger; haloperidol/atypicals with ECG monitoring; dexmedetomidine may help in ventilated patients with agitation preventing extubation.

You are asked to review sedation for a ventilated ICU patient. How do you structure your approach?

Aim for safe, goal-directed, analgesia-first, light sedation with daily review.

Confirm indication for sedation and set a sedation target (e.g., RASS 0 to −2 unless specific reason for deeper sedation).
Assess pain (BPS/CPOT), agitation (RASS/SAS), delirium (CAM-ICU/ICDSC), ventilator synchrony, and safety risks (self-extubation).
Look for reversible causes of agitation: pain, hypoxia/hypercapnia, sepsis, hypoglycaemia, withdrawal, urinary retention/constipation, environmental factors.
Optimise analgesia-first (opioid ± adjuncts) before increasing hypnotic.
Choose sedative based on haemodynamics, organ failure, need for neurological assessment and extubation plan (propofol vs dexmedetomidine vs midazolam).
Plan sedation hold and SBT if appropriate; ensure monitoring and prevention of complications (PRIS/QT/bradycardia).

Compare propofol, dexmedetomidine and midazolam for ICU sedation.

Examiners want a structured comparison: onset/offset, haemodynamics, respiratory effects, delirium, accumulation, special risks.

Propofol: rapid on/off, easy titration; hypotension; no analgesia; hypertriglyceridaemia; PRIS with high-dose/prolonged infusion.
Dexmedetomidine: cooperative sedation, minimal respiratory depression, helpful for weaning/extubation; bradycardia/hypotension; may be insufficient for deep sedation needs.
Midazolam: useful for seizures/withdrawal; accumulation and prolonged wake-up (esp. renal failure via active metabolite); associated with delirium; respiratory depression.

What is Propofol Infusion Syndrome (PRIS)? How do you recognise and manage it?

Classic FRCA viva topic: definition, risk factors, features, investigations, management.

Definition: rare, potentially fatal syndrome associated with prolonged/high-dose propofol infusion causing mitochondrial dysfunction and impaired fatty acid oxidation.
Risk factors: high dose and prolonged infusion, critical illness (sepsis/ARDS), catecholamines, steroids, low carbohydrate intake, young age (classically).
Features: high anion gap metabolic acidosis, rhabdomyolysis (↑CK), hyperkalaemia, acute kidney injury, lipaemia/↑triglycerides, hepatomegaly, ECG changes/arrhythmias, cardiac failure.
Investigations: ABG/lactate, U&E/K+, CK, triglycerides, LFTs, ECG/echo if instability; consider myoglobinuria.
Management: stop propofol immediately; switch sedation (e.g., dexmedetomidine/midazolam); supportive care (vasopressors/inotropes), treat hyperkalaemia/acidosis, consider RRT/ECMO in refractory cardiac failure; ensure adequate carbohydrate intake.

A ventilated patient is agitated. How do you differentiate pain, delirium and inadequate sedation, and what do you do?

Start with physiology and reversible causes; use validated tools.

Assess pain first (BPS/CPOT; check recent procedures, suctioning, drains, positioning). Treat with opioid bolus/infusion ± paracetamol/ketamine.
Assess sedation level (RASS) vs target; if under-sedated after analgesia, titrate sedative.
Screen for delirium (CAM-ICU) and address causes: sepsis, hypoxia, metabolic disturbance, withdrawal, sleep deprivation; implement non-pharmacological measures.
If severe agitation risk: short-term pharmacological control (e.g., dexmedetomidine if extubation goal; antipsychotic with ECG monitoring; avoid escalating benzos unless withdrawal).

Describe a sedation hold (daily interruption). When is it contraindicated?

Know the concept, benefits, and common contraindications.

Process: stop sedatives (continue analgesia as needed), monitor closely, reassess neuro status and readiness for SBT/extubation; restart at lower dose if required to target.
Benefits: reduces ventilation duration and ICU LOS; improves neuro assessment; reduces drug accumulation.
Contraindications/relative: ongoing neuromuscular blockade, refractory hypoxaemia/high PEEP with instability, active seizures/status epilepticus, raised ICP requiring deep sedation, severe agitation risking harm, therapeutic hypothermia/TTM phase, unstable haemodynamics.

How would you sedate a patient for weaning and extubation in ICU?

Aim for awake, cooperative patient with good analgesia and minimal respiratory depression.

Target light sedation (RASS −1 to 0) and ensure pain control; avoid over-sedation.
Consider dexmedetomidine to allow cooperative sedation with minimal respiratory depression; or reduce/stop propofol and use short-acting opioid strategy.
If using remifentanil, plan transition to longer-acting analgesia before stopping to avoid rebound pain/hyperalgesia.
Coordinate sedation reduction with SBT; treat delirium contributors; ensure airway plan and post-extubation analgesia/antiemesis.

Discuss ICU delirium: risk factors, consequences, prevention and treatment.

Delirium is common and associated with worse outcomes; prevention is largely non-pharmacological.

Risk factors: age, dementia, sepsis, hypoxia, organ failure, sleep deprivation, benzodiazepines, alcohol withdrawal, pain, immobility.
Consequences: longer ventilation/ICU stay, increased mortality, long-term cognitive impairment.
Prevention: analgesia-first, light sedation targets, minimise benzodiazepines, sleep promotion, reorientation, early mobilisation, sensory aids.
Treatment: identify/treat causes; if severe agitation endangering patient/staff consider haloperidol/atypicals (QT monitoring) or dexmedetomidine in ventilated patients where agitation prevents extubation.

How does renal failure affect your choice of sedative and analgesic drugs in ICU?

Key is avoiding active metabolite accumulation and prolonged wake-up.

Avoid/limit morphine (M6G accumulation) and midazolam (active metabolite accumulation) where possible; expect prolonged sedation if used.
Consider propofol (hepatic metabolism) with haemodynamic vigilance; consider dexmedetomidine; remifentanil is useful due to esterase metabolism (but plan analgesia transition).
Dose titration to effect, frequent reassessment, and use sedation holds to detect accumulation early.

A patient on dexmedetomidine becomes bradycardic and hypotensive. What are your steps?

Treat as drug-related until proven otherwise, but exclude other causes.

Assess ABCs, confirm rhythm, check perfusion; review other contributors (hypovolaemia, sepsis, beta-blockers, conduction disease).
Reduce or stop dexmedetomidine; avoid loading doses; consider alternative sedation if needed.
Treat hypotension with fluids if appropriate and vasopressors; treat symptomatic bradycardia per ALS (e.g., atropine) if required.

Outline a protocol for safe ICU sedation (what should be in it?).

Think: goals, scoring, drug ladder, holds, delirium, safety monitoring.

Defined sedation target (RASS) and pain target (BPS/CPOT), with documentation frequency and titration guidance.
Analgesia-first ladder (opioid choice, adjuncts, neuropathic pain options) and sedation agent choices with contraindications.
Daily sedation hold and SBT criteria; contraindications list; escalation plan for agitation/delirium.
Monitoring requirements and drug-specific labs (e.g., triglycerides/CK for propofol, ECG for QT-prolonging drugs).