Sedation in the intensive care unit: a systematic review

Sedation has become an integral part of critical care practice in minimizing patient discomfort; however, sedatives have adverse effects and the potential to prolong mechanical ventilation, which may increase health care costs.

To determine which form of sedation is associated with optimal sedation, the shortest time to extubation, and length of intensive care unit (ICU) stay.

A key word search of MEDLINE, EMBASE, and the Cochrane Collaboration databases and hand searches of 6 anesthesiology journals from 1980 to June 1998. Experts and industry representatives were contacted, personal files were searched, and reference lists of relevant primary and review articles were reviewed.

Studies included were randomized controlled trials enrolling adult patients receiving mechanical ventilation and requiring short-term or long-term sedation. At least 2 sedative agents had to be compared and the quality of sedation, time to extubation, or length of ICU stay analyzed.

Data on population, intervention, outcome, and methodological quality were extracted in duplicate by 2 of 3 investigators using 8 validity criteria.

Of 49 identified randomized controlled trials, 32 met our selection criteria; 20 studied short-term sedation and 14, long-term sedation. Of these, 20 compared propofol with midazolam. Most trials were not double-blind and did not report or standardize important cointerventions. Propofol provides at least as effective sedation as midazolam and results in a faster time to extubation, with an increased risk of hypotension and higher cost. Insufficient data exist to determine effect on length of stay in the ICU. Isoflurane demonstrated some advantages over midazolam, and ketamine had a more favorable hemodynamic profile than fentanyl in patients with head injuries.

Considering the widespread use of sedation for critically ill patients, more large, high-quality, randomized controlled trials of the effectiveness of different agents for short-term and long-term sedation are warranted.