Adverse Events in the Operating Room: Definitions, Prevalence, and Characteristics. A Systematic Review

The ongoing debate on the incidence and types of iatrogenic injuries in American hospitals has been informed primarily by the Harvard Medical Practice Study, which analyzed hospitalizations in New York in 1984. The generalizability of these findings is unknown and has been questioned by other studies. We used methods similar to the Harvard Medical Practice Study to estimate the incidence and types of adverse events and negligent adverse events in Utah and Colorado in 1992. We selected a representative sample of hospitals from Utah and Colorado and then randomly sampled 15,000 nonpsychiatric 1992 discharges. Each record was screened by a trained nurse-reviewer for 1 of 18 criteria associated with adverse events. If > or =1 criteria were present, the record was reviewed by a trained physician to determine whether an adverse event or negligent adverse event occurred and to classify the type of adverse event. The measures were adverse events and negligent adverse events. Adverse events occurred in 2.9+/-0.2% (mean+/-SD) of hospitalizations in each state. In Utah, 32.6+/-4% of adverse events were due to negligence; in Colorado, 27.4+/-2.4%. Death occurred in 6.6+/-1.2% of adverse events and 8.8+/-2.5% of negligent adverse events. Operative adverse events comprised 44.9% of all adverse events; 16.9% were negligent, and 16.6% resulted in permanent disability. Adverse drug events were the leading cause of nonoperative adverse events (19.3% of all adverse events; 35.1% were negligent, and 9.7% caused permanent disability). Most adverse events were attributed to surgeons (46.1%, 22.3% negligent) and internists (23.2%, 44.9% negligent). The incidence and types of adverse events in Utah and Colorado in 1992 were similar to those in New York State in 1984. Iatrogenic injury continues to be a significant public health problem. Improving systems of surgical care and drug delivery could substantially reduce the burden of iatrogenic injury.

Despite more than three decades of research on iatrogenesis, surgical adverse events have not been subjected to detailed study to identify their characteristics. This information could be invaluable, however, for guiding quality assurance and research efforts aimed at reducing the occurrence of surgical adverse events. Thus we conducted a retrospective chart review of 15,000 randomly selected admissions to Colorado and Utah hospitals during 1992 to identify and analyze these events. We selected a representative sample of hospitals from Utah and Colorado and then randomly sampled 15,000 nonpsychiatric discharges from 1992. With use of a 2-stage record-review process modeled on previous adverse event studies, we estimated the incidence, morbidity, and preventability of surgical adverse events that caused death, disability at the time of discharge, or prolonged hospital stay. We characterized their distribution by type of injury and by physician specialty and determined incidence rates by procedure. Adverse events were no more likely in surgical care than in nonsurgical care. Nonetheless, 66% of all adverse events were surgical, and the annual incidence among hospitalized patients who underwent an operation or child delivery was 3.0% (confidence interval 2.7% to 3.4%). Among surgical adverse events 54% (confidence interval 48.9% to 58.9%) were preventable. We identified 12 common operations with significantly elevated adverse event incidence rates that ranged from 4.4% for hysterectomy (confidence interval 2.9% to 6.8%) to 18.9% for abdominal aortic aneurysm repair (confidence interval 8.3% to 37.5%). Eight operations also carried a significantly higher risk of a preventable adverse event: lower extremity bypass graft (11.0%), abdominal aortic aneurysm repair (8.1%), colon resection (5.9%), coronary artery bypass graft/cardiac valve surgery (4.7%), transurethral resection of the prostate or of a bladder tumor (3.9%), cholecystectomy (3.0%), hysterectomy (2.8%), and appendectomy (1.5%). Among all surgical adverse events, 5.6% (confidence interval 3.7% to 8.3%) resulted in death, accounting for 12.2% (confidence interval 6.9% to 21.4%) of all hospital deaths in Utah and Colorado. Technique-related complications, wound infections, and postoperative bleeding produced nearly half of all surgical adverse events. These findings provide direction for research to identify the causes of surgical adverse events and for targeted quality improvement efforts.