A Multicenter Study of the Point Prevalence of Drug-Induced Hypotension in the ICU

Objective: To determine the point prevalence of drug-induced hypotension episodes in critically ill patients, to assess the episodes resulting from error, and to describe how episodes are treated. Design: Multicenter observational, 24-hour snapshot study. Setting: Forty-seven ICUs in 27 institutions located in the United States, Canada, and Singapore. Patients: A total of 688 ICU patients were evaluated. Interventions: None. Measurements and Main Results: Patients were included in the study if they had an episode of hypotension in the 24 hours prior to the clinical pharmacists' evaluation. The definition for a hypotensive episode is either a systolic blood pressure less than 90 mm Hg or a decrease in systolic blood pressure of 30 mm Hg over a 2-hour period. Each episode of unintentional hypotension was assessed for suspected drug-related causes. When a drug-related cause was suspected, an objective assessment tool, the modified Kramer, was used to determine causality. A score of at least "possible" was considered drug induced, referred to as a "drug-related hazardous condition." A drug-related-hazardous condition is the temporal gap (intermediate stage) between the identification of an adverse drug reaction and the subsequent onset of drug-induced injury, known as an "adverse drug event." Drug-induced episodes were evaluated for medication errors and treatment. One hundred fifty-eight patients experienced 204 hypotensive episodes that were considered unintentional and drug related. Common drugs implicated included propofol, fentanyl, metoprolol, lorazepam, hydralazine, and furosemide. A total of 54 episodes (26.5%) resulted from medication errors. Common error types were improper dose/quantity (46%) and prescribing (25%). A total of 56.9% episodes were treated. Conclusions: Many hypotensive episodes in the ICU are drug related and require treatment. A substantial portion of these episodes result from errors and are therefore preventable. This presents opportunities to improve prescribing including optimizing drug dosing to avoid possible patient harm from drug-induced hypotension.