Errors and adverse outcomes on a surgical service: what is the role of residents?

The extensive changeover in residents that occurs every July in university-affiliated hospitals has been postulated to result in impaired delivery of patient care as new house staff are less experienced and unfamiliar with hospital-specific systems (the "July phenomenon"). To assess the impact of this process on patient safety, we examined the incidence and sources of medical error and adverse outcomes on a pediatric general surgery service during the final month of an academic year and the first month of the subsequent academic year.

All admissions to two pediatric surgeons during June and July 2002 were prospectively followed. The attending surgeon, a surgical fellow, and a medical student reviewed in-patient care daily. Errors committed by doctors, nurses, and allied health workers were identified through daily patient encounters, nursing rounds, medical rounds, and chart audit. Adverse outcomes were evaluated based on type and contributing factors, including involvement of residents. To correct for variations in patient volume, the incidence of errors and adverse outcomes were expressed as a percentage of total patient days.

The error rate was 46/643 patient days (7.1%) in June, and 58/776 patient days (7.5%) in July (P = 0.9). Resident error accounted for 52.2% of errors in June and 39.7% of errors in July (P = 0.28). There was no significant difference in the adverse outcome rates (5% versus 6.7%, P = 0.21) or incidence of error-related adverse outcomes (10.8% versus 22.4%, P = 0.2) between June and July. Most errors were made by the on-call resident.

Resident changeover at the completion of an academic year did not result in an increased number of medical errors or adverse outcomes, indicating that effective systems are in place to prevent the "July phenomenon."