Impact of Resident Overnight Duty Hour Changes on Obstetrical Outcomes: A Population-Based Cohort Study [23OP

Abstract

INTRODUCTION: The Obstetrics program at the University of Toronto recently adopted a “night float” system, whereby residents work for a restricted number of hours overnight, but for four consecutive nights. The objective of this study was to determine if there has been a change in obstetrical patient outcomes following the introduction of restricted resident work hours. METHODS: We performed a population-based, retrospective cohort study using linked healthcare administrative databases in the province of Ontario, Canada. We included all obstetrical patients who underwent a delivery between July 2011 and June 2015 (two years prior to and after the implementation of resident duty hour restrictions), at three academic hospitals in Toronto, Canada. The primary outcome was a composite index of numerous maternal/fetal outcomes including maternal transfusion/postpartum hemorrhage, maternal infection, fetal mortality, NICU admissions and surgical/obstetrical complications. Secondary outcomes included assessment of each of the components of the primary outcome examined separately. A generalized estimating equation model, clustered by institution, was utilized to assess for a difference post-intervention. RESULTS: The pre-intervention cohort consisted of 6,763 deliveries, and the post-intervention cohort 5,548 deliveries. There were no differences in baseline patient demographics between groups. After the implementation of the restrictions, no significant difference was seen in the primary outcome. However, an increased incidence of composite maternal surgical/obstetrical outcomes (OR 1.2298, P=.0016) and transfusion/postpartum hemorrhage (OR 1.2629, P=.0006) was found. CONCLUSION: Since the implementation of resident duty hour restrictions with the addition of consecutive night shifts, there was an increased incidence of surgical/obstetrical complications and transfusion/postpartum hemorrhage.