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

2. Future studies should evaluate the consequences of one anesthesiologist covering multiple operating rooms under direct care by anesthesiology residents.

Evidence Rating Level: 2 (Good)

Study Rundown: Overlapping responsibilities across different medical specialties has been linked to poor patient outcomes. However, this has not been studied well in anesthesiology, where this practice is prevalent; in particular, overlapping responsibilities occur in models where certified registered nurse anesthetists (CRNAs), anesthesia assistants, or anesthesiology residents are supervised by an anesthesiologist. This retrospective cohort study evaluated whether there was an association between varying anesthesiology staffing ratios and patient major morbidity or mortality. The Multicenter Perioperative Outcomes Group (MPOG) database was used to obtain data from 23 hospitals in 18 U.S. states between January 1, 2010, to October 31, 2017. Operations were included if an anesthesiologist was supervising rooms directly under the care of CRNAs or ones with less than 25% resident involvement; operations were excluded if care was provided directly by the staff anesthesiologist. Propensity-score matching was used to develop groups; groups were created depending on how many operations the staff anesthesiologist was covering (group 1: staffing ratio of 1; group 1-2: staffing ratio between 1 and 2; group 2-3: staffing ratio between 2 and 3; group 3-4: staffing ratio between 3 and 4). The primary outcome was a composite of 30-day mortality and six major surgical co-morbidities (cardiac, respiratory, gastrointestinal, urinary, bleeding, and infectious). Compared to group 1-2, patients in group 2-3 had a 4% relative increase (adjusted odds ratio [AOR]: 1.04 [95% CI: 1.01-1.18]; p= 0.02) and those in group 3-4 had a 14% relative increase (AOR: 1.15 [95% CI: 1.09-1.21]; p< 0.001) in risk of major morbidity or mortality. Additionally, group 3-4 was significantly more likely to suffer from morbidity or mortality than group 2-3 (AOR: 1.10 [95% CI: 1.04-1.16]; p= 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 surgical procedures performed each year, these outcomes have major implications. One limitation of this study, however, is the strict exclusion criteria, such as limiting resident involvement to less than 25% in an operating room to be included in the study; further research into 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

Image: PD

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