CNS Drugs

, Volume 11, Issue 1, pp 9–22 | Cite as

Sedation in Critically Ill Patients

Practical Recommendations
  • Normand R. Gravel
  • Norman R. Searle
  • Philippe G. Sahab
  • Michel Carrier
Disease Management


Provision of anxiolysis and analgesia in critically ill patients is mandatory to improve patient comfort without undue autonomic or haemodynamic adverse effects. The assessment of the level of sedation in the intensive care unit (ICU) by means of scoring systems is important because both undersedation and over-sedation can be counterproductive. Scoring systems, such as the Ramsay Sedation Score or the Modified Observer’s Assessment of Alertness/Sedation Scale, offer an accurate means of communicating clinical information and monitoring clinical progress.

Understanding how the pharmacokinetic and pharmacodynamic profiles of sedative and analgesic agents are altered in critically ill patients is essential for administering effective care. Midazolam and lorazepam are commonly used to provide anxiolysis and amnesia. Although there are variations in morphine metabolism and/or excretion in certain disease states, it remains the opioid of choice for critically ill patients. Because of its unique pharmacokinetic properties, remifentanil may eventually prove to be an interesting alternative. Propofol possesses many characteristics of the ideal sedative agent: rapid onset of effect, easy titration, unaltered pharmacokinetics in hepatic and renal dysfunction, and rapid recovery after prolonged infusion.

Conditions most likely encountered in the ICU are reviewed and practical recommendations are provided. Sedation in patients with multiple organ failure raises several interesting problems regarding distribution volumes, plasma protein binding, metabolic rate, tissue perfusion, drug excretion and requirement for prolonged sedation. Weaning from prolonged sedation can be difficult and may reveal drug dependency. The use of propofol can ease the transition from long term benzodiazepine use.

Patients with respiratory failure are a special group in whom propofol seems to have a favourable profile. Unless absolutely necessary, neuromuscular blocking agents should be avoided. If these agents must be used, it is incumbent to provide appropriate sedation and monitor the neuromuscular junction with a peripheral nerve stimulator. Opioid drugs should be used sparingly.

Compared with other medical conditions, sedation post-cardiac surgery has received a lot of attention. Propofol or midazolam in association with morphine are effective and well tolerated. Both can be use for short term sedation without jeopardising early tracheal extubation.


Intensive Care Unit Morphine Fentanyl Adis International Limited Midazolam 
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Copyright information

© Adis International Limited 1999

Authors and Affiliations

  • Normand R. Gravel
    • 1
  • Norman R. Searle
    • 1
  • Philippe G. Sahab
    • 1
  • Michel Carrier
    • 1
  1. 1.Department of AnaesthesiaMontreal Heart InstituteMontrealCanada

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