• Marie-Hélène Masse, AdhikariNeill K JNKJInterdepartmental Division of Critical Care Medicine, University of Toronto, 209 Victoria Street, Toronto, Ontario, M5B 1T8, Canada.Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, Toronto, , Xavier Théroux, Marie-Claude Battista, Frédérick D'Aragon, Ruxandra Pinto, Alan Cohen, Michaël Mayette, Charles St-Arnaud, Michelle Kho, Michaël Chassé, Martine Lebrasseur, Irene Watpool, Rebecca Porteous, M Elizabeth Wilcox, and François Lamontagne.
• Faculty of Medicine and Health Sciences, Université de Sherbrooke, 12e Avenue Nord, Sherbrooke, Québec, J1H 5N4, Canada.
• BMC Anesthesiol. 2022 Jan 3; 22 (1): 6.

BackgroundIn randomized clinical controlled trials, the choice of usual care as the comparator may be associated with better clinician uptake of the study protocol and lead to more generalizable results. However, if care processes evolve to resemble the intervention during the course of a trial, differences between the intervention group and usual care control group may narrow. We evaluated the effect on mean arterial pressure of an unblinded trial comparing a lower mean arterial pressure target to reduce vasopressor exposure, vs. a clinician-selected mean arterial pressure target, in critically ill patients at least 65 years old.MethodsFor this multicenter observational study using data collected both prospectively and retrospectively, patients were recruited from five of the seven trial sites. We compared the mean arterial pressure of patients receiving vasopressors, who met or would have met trial eligibility criteria, from two periods: [1] at least 1 month before the trial started, and [2] during the trial period and randomized to usual care, or not enrolled in the trial.ResultsWe included 200 patients treated before and 229 after trial initiation. There were no differences in age (mean 74.5 vs. 75.2 years; p = 0.28), baseline Acute Physiology and Chronic Health Evaluation II score (median 26 vs. 26; p = 0.47) or history of chronic hypertension (n = 126 [63.0%] vs. n = 153 [66.8%]; p = 0.41). Mean of the mean arterial pressure was similar between the two periods (72.5 vs. 72.4 mmHg; p = 0.76).ConclusionsThe initiation of a trial of a prescribed lower mean arterial pressure target, compared to a usual clinician-selected target, was not associated with a change in mean arterial pressure, reflecting stability in the net effect of usual clinician practices over time. Comparing prior and concurrent control groups may alleviate concerns regarding drift in usual practices over the course of a trial or permit quantification of any change.© 2021. The Author(s).

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