BACKGROUND: There are different views on the effects of resident involvement on surgical outcomes. We hypothesized that resident participation in surgical care does not appreciably alter outcomes.

STUDY DESIGN: We analyzed an American College of Surgeons NSQIP subset of inpatients having procedures with high complexity, including 4 surgical specialties (general surgery, cardiothoracic surgery, neurosurgery, and vascular surgery) with the highest mean work relative value units. We evaluated surgical outcomes in patients having procedures performed by the attending surgeon alone, or by the attending surgeon with assistance from at least one surgical resident (PGY1 to PGY≥6). Outcomes measures included operative mortality, composite morbidity, and failure to rescue (FTR). Propensity-score matching minimized the effects of nonrandom assignment of residents to procedures.

RESULTS: In 266,411 patients, unmatched comparisons showed significantly higher operative mortality and composite morbidity rates, but decreased FTR, in operations performed with resident involvement. After propensity-score matching, there were small but significant resident-related increases in composite morbidity, but significant improvement in FTR. Senior-level resident involvement translated into improved outcomes, especially in cardiothoracic surgery procedures where >63.6% of procedures had PGY≥6 resident involvement. Resident involvement attenuated the significant worsening of operative mortality and FTR associated with multiple serious complications in individual patients. Measures of resource use increased modestly with resident involvement.

CONCLUSIONS: We found substantial improvement in FTR with resident involvement, both in unmatched and propensity-matched comparisons. Senior-level resident participation seemed to attenuate, and even improve, surgical outcomes, despite slightly increased resource use. These results provide some reassurance about teaching paradigms.