At the time of enrollment, the following baseline demographic data was collected: age, gender, past medical history, ICU admitting service, primary ICU admitting diagnosis and the Acute Physiology and Chronic Health Evaluation (APACHE) II score at ICU admission [62]. The specific PRIS-associated clinical manifestations and risk factors used in this study were identified from PRIS published case reports [2-57]. These case reports were identified from a MEDLINE search (1980 to December 2007), using the following search terms: propofol, propofol infusion syndrome, propofol-related infusion syndrome, PRIS, rhabdomyolysis and adverse drug events. This strategy is similar to that used in a recent evaluation of the FDA MEDWATCH database [58].Based on the above analysis, PRIS-associated clinical manifestations were grouped under nine categories and defined as follows: rhabdomyolysis (CPK �� 10,000 IU/L); hypotension (systolic blood pressure �� 90 mmHg or current use of a vasopressor agent); hepatic transaminitis (increase in the aspartate aminotransferase and/or alanine aminotransferase �� 3 times above baseline); metabolic acidosis (arterial pH �� 7.30 along with a serum bicarbonate �� 18 mg/dL); hypertriglyceridemia (serum triglyceride concentration �� 400 mg/dL); hypoxia (partial pressure of arterial oxygen �� 60 mmHg); hyperthermia (temperature �� 38.3��C); cardiac dysfunction that included a Brugada-like ECG pattern, asystole, pulseless electrical activity, ventricular fibrillation, sustained ventricular tachycardia of 30 seconds or longer, myocardial failure (ejection fraction �� 40%), or bradycardia (heart rate �� 50 bpm not felt to be related to a medication other than propofol); and renal failure that included oliguria (urine output �� 0.5 mL/kg/hr for �� 6 hours), anuria (urine output �� 10 mL/hr for �� 6 hours), elevation in serum creatinine (increase of �� 1 mg/dL from baseline), or hyperkalemia (serum K+ �� 6 mg/dL (excluding other known causes or hemolyzed specimens)). A patient was deemed to have experienced a particular manifestation category if they experienced any manifestation within the category. The presence of known risk factors for PRIS (i.e., a high propofol dose (= 83 ��g/kg/min (5 mg/kg/hr)) at any time point and concomitant vasopressor therapy) were also identified [59-61].Patients were monitored daily for the presence of each PRIS manifestation and risk factor by an experienced critical care pharmacist at baseline, during the period of propofol administration (up to 30 days), and then for 24 hours after propofol was discontinued.