Propofol, a commonly used surgical anesthetic, is safer than midazolam for sedating critically ill patients on mechanical ventilation, according to researchers.

In a large study, a team led by Alexandre Braga Libório, of the Federal University of Ceará in Ceará, Brazil, demonstrated that propofol use was associated with a significantly lower risk of adverse renal outcomes, including acute kidney injury (AKI), fluid-related complications, and need for renal replacement therapy (RRT) compared with midazolam use.

The study included 698 propofol-treated patients closely matched to the same number of midazolam-treated patients. All were adults experiencing their first intensive care unit (ICU) admission and all required mechanical ventilation.

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The incidence of AKI in the first 7-day ICU time period was lower in the propofol than midazolam group using both urine output criteria (45% vs. 55.7%) and serum creatinine criteria (28.8% vs. 37.2%), Dr. Libório’s group reported online ahead of print in the Clinical Journal of the American Society of Nephrology. Oliguria (less than 400 mL/day) occurred significantly less frequently in the propofol than midazolam group (12.4% vs. 19.6%). In addition, propofol-treated patients had diuretics prescribed less frequently than the midazolam-treated patients (8.5% vs. 14.3%). The need for RRT in the first 7 days of ICU stay occurred significantly less often in the propofol than midazolam group (3.4% vs. 5.9%). The ICU mortality rate was significantly lower in the propofol recipients (14.6% vs. 29.7%).

Critically ill patients often are managed using a continuous-infusion sedative for comfort and to reduce anxiety, the researchers explained. The ICU sedation strategy can include either benzodiazepine or non-benzodiazepine medications. Propofol has anti-inflammatory and immunomodulatory properties in addition to its intrinsic anesthetic properties, they pointed out. It has been shown to provide protection against renal ischemia/reperfusion injury experimentally, but clinical evidence is limited to patients undergoing cardiac surgery. The investigators cited a recent randomly controlled study showing that propofol anesthesia was associated with a decrease in AKI incidence compared with sevoflurane anesthesia in patients undergoing valvular heart surgery (Yoo YC et al. Kidney Int 2014;86:414-422).

Dr. Libório and his colleagues obtained data for their study from the Multiparameter Intelligent Monitoring in Intensive Care II database, which is maintained by the Massachusetts Institute of Technology Laboratory for Computational Physiology in Boston. The database contains data from patients hospitalized in an ICU at Beth Israel Deaconess Medical Center in Boston from 2001 to 2008.

The use of this large and detailed database was among the study strengths, the authors noted “The detailed information provided by this database is of utmost importance, because it enables it to expand the baseline characteristics beyond the possibilities of an administrative database,” they wrote.

The investigators also acknowledged study limitations, including the retrospective nature of the study, the use of data from a single center, and a relatively low number of patients receiving midazolam.