Critically ill patients in the intensive care unit (ICU) who are intubated and mechanically ventilated typically experience pain, anxiety, and other forms of discomfort that are often accompanied by agitation, sleep deprivation, and psychosis [1–4]. Inadequately treated discomfort and agitation in these patients can have detrimental cardiopulmonary and metabolic consequences such as tachycardia, hypertension, arrhythmias, myocardial ischemia, and increases in oxygen consumption and carbon dioxide production which can contribute significantly to increased morbidity and mortality [5–9]. Traditionally, opioids, benzodiazepines, and neuroleptics have been used most commonly for sedation of patients in the ICU . Long-term administration of these medications to critically ill patients may result in persistent sedation, cognitive deficits, and/or respiratory depression following discontinuation of these drugs due to accumulation of either the parent compound or active metabolites [11–18]. Propofol is a short-acting intravenous sedative-hypnotic agent which has been used for several years in both the United States and in Europe for general anesthesia and intra-operative sedation. Propofol has become an attractive alternative to other medications used for sedation of patients in the ICU because of its rapid onset and offset of sedation and its low side-effect profile, even with long-term administration to critically ill patients.