Rationale: Cross-coverage is associated with medical errors caused by miscommunication during handoffs. However, no direct evidence links handoffs to outcomes, or explains the mechanisms leading to outcomes. Furthermore, the previous literature may overestimate the impact of handoffs because of hindsight bias.
Objectives: To explore the effects of nighttime cross-coverage on mortality and decision making in critically ill patients.
Methods: Observational cohort of 629 consecutive critically ill admissions, admitted for at least 48 hours, and critical care fellows in an academic hospital.
Measurements and main results: Intensive care unit (ICU) mortality and nighttime decisions. Our exposure variable was cross-covering status of fellows. We observed a decrease in ICU mortality (odds ratio, 0.77 per 1 d; 0.60-0.99; P = 0.04), a higher number of nighttime decisions (19.3 vs. 10.4%; odds ratio, 2.02; 95% confidence interval [CI], 1.03-3.95; P = 0.04), an increase in fentanyl equivalents administered to patients at night (difference, +10.2 μg/h; 95% CI, +1.4 to +19.0; P = 0.02), and an increase in transfusions at night (difference, +465 ml; 95% CI, +98 to +832; P = 0.01) when fellows were cross-covering.
Conclusions: In this single-center study exposure to cross-covering fellows was associated with a decrease in ICU mortality and with more nighttime decisions. Our findings contradict the dominant hypothesis that cross-coverage is associated with worse outcomes, and suggest that a "second look" by cross-covering fellows may mitigate cognitive errors. Future interventions to improve patient safety in ICUs should focus both on the quality of handoffs and on strategies to decrease cognitive errors.