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Among the key innovations of critical care medicine is treatment directed by continuously measured objective physiologic data. A prime example is the dosing of vasopressors using continuous measurements of systemic arterial pressure acquired from an indwelling arterial catheter. Similarly, the settings of mechanical ventilators are based on pressure and volume measurements of airway gases and arterial blood gas analysis. However, not all of the care provided in ICUs is so carefully monitored and titrated. This is especially true concerning sedation and analgesia, which are widely used in ICUs, as reported in this issue of CHEST (see page 496), by Arroliga and colleagues. These investigators analyzed data from a prospective, multicenter, international cohort of 5,183 adult ICU patients who received mechanical ventilation for > 12 h in 361 ICUs. Sixty-eight percent of these patients received sedation while being mechanically ventilated, while 13% also received a neuromuscular blocker for at least 1 day. The latter patients had a 50% mortality rate. The sedated patients had longer durations of mechanical ventilation, weaning time, and ICU stays than nonsedated patients. These results are not unexpected since patients receiving sedation and neuromuscular blockade tend to be the most severely ill. However, there is always the lingering question as to whether sedation, analgesia, and administration of neuromuscular blockers contribute to the morbidity and mortality of such patients or are only indications of severe illness.
Critically ill patients are constantly subjected to noxious stimuli, unpleasant experiences, and pain. They require sedatives, amnesties, and analgesics to reduce anxiety and suffering, to control pain, and to manage agitation. Despite the frequent use of these pharmacologie modalities, there is a lack of consensus as to the following: (1) when to administer these drugs, (2) which drugs to administer, (3) the depth of sedation required, and (4) how to monitor the depth of sedation and adequacy of analgesia. This lack of consensus is occasioned by the absence of well-designed and conclusive studies examining these issues.1 Additionally, there are relatively few studies examining when and how to use neuromuscular blocking agents in critically ill patients.1
Much of the knowledge mid many of the drugs used to sedate, reduce pain, and pharmacologically paralyze patients in the ICU have been adapted from the operating room environment.1 However, there are...