CARING FOR THE CRITICALLY ILL PATIENT Sedation in the Intensive Care Unit A Systematic Review

TO MINIMIZE PATIENT DISCOMfort in the intensive care unit (ICU), sedation has become an integral part of critical care practice. Sedation reduces the stress response, provides anxiolysis, improves tolerance of ventilatory support, and facilitates nursing care. Unfortunately, sedatives have adverse effects, have the potential to prolong mechanical ventilation, and may increase health care costs. An ideal sedative agent would have rapid onset of action, be effective at providing adequate sedation, allow rapid recovery after discontinuation, be easy to administer, lack drug accumulation, have few adverse effects, interact minimally with other drugs, and be inexpensive. The lack of a recognized ideal sedative has resulted in varied approaches to sedation both among and within intensive care units (ICUs). In a survey of 164 ICUs in the United States, 18 different sedative agents were used. The most common agents listed were morphine sulfate, lorazepam, midazolam, diazepam, and haloperidol. Intensive care unit consultants in the United Kingdom reported use of 11 different agents in another survey. Similarly, Dasta et al reported the use of 23 different drugs for sedation, anxiety, and pain relief in their surgical ICU. These surveys indicate wide practice variation in sedative administration for critically ill patients. A number of narrative review articles have summarized the principles of sedation and the range of available agents. In 1992, the Society of Critical Care Medicine (SCCM) Task Force developed practice parameters for sedation in the ICU based on available scientific data, clinical expertise, and experience. After careful review and discussion, this group recommended the use of midazolam or propofol for shortterm (#24 hours) sedation, lorazepam for longer-term (.24 hours) sedation, and haloperidol for delirium. The level of evidence available from the literature for these reviewers was somewhat limited at the time, and these useful clinical recommendations required heavy reliance on expertise. A survey by Rhoney