1. This retrospective cohort study of 866,453 adults demonstrated that as the responsibilities of anesthesiologists overlapped, the risk of 30-day morbidity and mortality for surgical patients increased.

2. Future studies should assess the consequences of an anesthetist spanning multiple operating rooms under the direct care of anesthesiology residents.

Level of evidence assessment: 2 (good)

Summary of the study: Overlapping responsibilities between different medical specialties has been linked to poor patient outcomes. However, this has not been well studied in anesthesiology, where this practice is widespread; in particular, overlapping responsibilities occur in models where certified registered nurse anesthesiologists (CRNs), anesthesia assistants, or anesthesiology residents are supervised by an anesthesiologist. This retrospective cohort study assessed whether there was an association between different anesthesiology staffing ratios and major patient morbidity or mortality. The Multicenter Perioperative Outcomes Group (MPOG) database was used to obtain data from 23 hospitals in 18 US states between January 1, 2010 and October 31, 2017 with less than 25% resident participation; operations were excluded if care was provided directly by the staff anesthesiologist. Propensity score matching was used to develop groups; groups were created according to the number of operations covered by the anesthetist staff (group 1: staff ratio of 1; group 1-2: staff ratio between 1 and 2; group 2-3: ratio of numbers between 2 and 3; group 3-4: ratio of numbers between 3 and 4). The primary outcome was a composite of 30-day mortality and six major surgical comorbidities (cardiac, respiratory, gastrointestinal, urinary, hemorrhagic, and infectious). Compared to group 1-2, patients in group 2-3 had a relative increase of 4% (odds ratio adjusted [AOR]: 1.04 [95% CI: 1.01-1.18]; p= 0.02) and those in group 3-4 had a relative increase of 14% (AOR: 1.15 [95% CI: 1.09-1.21]; pp= 0.001). Overall, as overlapping anesthesiologist coverage increased, surgical patient morbidity and 30-day mortality risk increased. Despite small increases in risk, these results were still statistically significant; given the millions of surgeries performed each year, these findings have major implications. A limitation of this study, however, is the strict exclusion criteria, such as limiting resident participation to less than 25% in an operating room to be included in the study; further research on the consequences of supervising multiple residents should be considered to better understand these effects.

Click to read the study in JAMA Surgery

Click to read an accompanying editorial in JAMA

Relevant reading: Association of overlapping surgery with perioperative outcomes

Picture: PD

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