"improving intensive care in Scotland"

Other sedative agents used in the ICU


  • Is contraindicated as a sedative in ICU patients.

  • It abolishes adrenal cortical steroid production and was found to increase mortality when administered to critically ill patients by infusion.


  • Is still used by continuous intravenous infusion for refractory status epilepticus andintractable intracranial hypertension. This is predominately in children and less commonly in adults.

  • Thiopentone obeys saturation kinetics (i.e. the liver enzymes metabolizing it become completely saturated and thus the drug accumulates markedly) during continuous infusion, resulting in an extremely protracted duration of action.


  • Is an NMDA-receptor antagonist.

  • Produces dissociative anaesthesia (profound analgesia, mild sedation, amnesia and reduced motor activity), making it very useful for procedural analgesia (e.g. burns dressings).

  • Produces sympathetic stimulation with its benefits being related to this (and therefore its lack of cardiovascular and respiratory depression) leading to its use as a treatment for life threatening asthma/severe unresponsive bronchospasm and anaesthesia for shocked patients.

  • Ketamine does have notable side effects:

    - Unpleasant dreams, emergence delirium, hallucinations

    • Increased cerebral metabolic rate (contraindicated in raised ICP)

    • Increased myocardial oxygen consumption (cautious use in patients with coronary artery disease).

Inhalational anaesthetics:

  • E.G. sevoflurane, desflurane, isoflurane

  • Can and have been used for sedation in ICU, though their use is not common place.

  • Their main limitations are with difficult/non-practical administration and scavenging and high cost.

  • They may have a role in managing life threatening asthma/severe unresponsive bronchospasm in mechanically ventilated patients in the ICU.

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