Adverse events detected by clinical surveillance on an obstetric service

OBJECTIVE: Adverse events are adverse patient outcomes resulting from medical care. We performed this study to estimate the rate of adverse events and potential adverse events-errors that have a high likelihood of causing patient harm-occurring during obstetric care. METHODS: This was a prospective cohort study of an obstetric unit in a teaching hospital. We included patients admitted consecutively to the hospital. A trained observer monitored patients for 72 triggers, which were predefined occurrences deemed likely to indicate an actual or potential adverse event. When a trigger occurred, the observer captured information describing it. A five-person multidisciplinary team, including the observer, three physicians, and a hospital risk manager, judged whether the trigger represented an adverse event or potential adverse event. Adverse events were further characterized as preventable. RESULTS: The cohort included 425 patients; 47% were in active labor. We identified 110 triggers. Nine were considered adverse events (risk 2%, 95% confidence interval [CI] 1-4%, rate 0.8 events per 100 patient days), and six were preventable (risk 1%, 95% CI 0-3%, rate 0.5 events per 100 patient days). The remaining triggers included 14 potential adverse events (risk 3%, 95% CI 2-5%, rate 1.3 events per 100 patient days). No adverse event resulted in permanent disability or death. Adverse events and potential adverse events were most commonly "system" problems, such as unavailable staff or operating rooms, or poor fetal outcomes, such as trauma to the newborn. CONCLUSION: Serious adverse events occur infrequently on an obstetric service. However, important quality problems are common and should be targeted for improvement.