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American Academy of Emergency Medicine

Medical Errors and Injury and Emergency Medicine

The Nature of Adverse Events in Hospitalized Patients - Results of the Harvard Medical Practice Study II
Lucian L. Leape, M.D., Troyen A. Brennan, M.D., J.D., M.P.H., Nan Laird, Ph.D., Ann G. Lawthers, Sc.D., A. Russell Localio, J.D., M.P.H., Benjamin A. Barnes, M.D., Liesi Herbert, Sc.D., Joseph P. Newhouse, Ph.D., Paul C. Weiler, LL.M., and Howard Hiatt, M.D.

NEJM. 1991;6:377-384.

This was the pioneering study on medical errors and injury.

In a sample of 30,195 randomly selected hospital records, the authors identified 1133 patients (3.7 percent) with disabling injuries caused by medical treatment. The study reports an analysis of these adverse events and their relation to error, negligence, and disability. Approximately 3 percent of the adverse events occurred in the Emergency Department. Importantly, the Emergency Department had the highest proportion of adverse events due to negligence of any area of the hospital.

The high rate of negligence in adverse events resulting from treatment in the Emergency Department were likely caused by several factors. Because no operations and only a few procedures are performed in the Emergency Department, the adverse events identified there were more likely to involve diagnostic errors or mishaps of noninvasive treatment, which the reviewers frequently judged as negligent. The following quote from the article speaks to the importance of having high quality, board-certified emergency physicians. "Emergency Departments are sometimes staffed with part time physicians who are not well trained in emergency care. Because they are frequently very busy, these physicians have less time to spend with each patient. Finally, some of the sickest patients enter the hospital through the Emergency Department". The authors noted that in a prior study 58 percent of patients with severe trauma treated in the Emergency Department had serious errors in treatment.

Although the prevention of many adverse events must await improvements in medical knowledge, the high proportion that are due to management errors suggests that many others are potentially preventable now. Reducing the incidence of these events will require identifying their cause and developing methods to prevent error or reduce its effects.