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Hospitals that operate at or over capacity are more likely to have patient safety problems

Under pressure to maximize revenue and minimize costs, many hospitals are providing more complex care to more patients with fewer staff. Yet, hospitals that operate at or over capacity are likely to experience more patient safety problems, according to a new study. These hospitals should consider re-engineering the structures of care to respond better during periods of high stress on hospital capacity, suggests Joel S. Weissman, Ph.D., of Harvard Medical School and Massachusetts General Hospital. His team examined rates of adverse events—ranging from hospital-acquired infections and medication reactions to pressure sores and falls—and peak hospital workload at two large urban and two smaller suburban teaching hospitals over a 1-year period in 2000 and 2001.

The researchers characterized daily workload for each hospital by volume throughput (number of daily admissions and discharges), intensity (case complexity or severity of illness of patients being cared for), and staffing (patient-to-nurse ratios). They screened medical records to find 6,841 patients who suffered an adverse event. One urban teaching hospital had occupancy rates over 100 percent for more than one fourth of the year. At that hospital, increasing the occupancy rate by 10 percent increased the rate of adverse events by 15 percent, while a 0.1 increase in the patient-to-nurse ratio led to a 28 percent increase in the adverse event rate.

Results at the other three hospitals varied and were mainly nonsignificant. High workload may be risky at organizations with little room for slack, conclude the researchers.

Their study was supported by the Agency for Healthcare Research and Quality (HS12035). More details are in "Hospital workload and adverse events," by Dr. Weissman, Jeffrey M. Rothschild, M.D., M.P.H., Eran Bendavid, M.D., and others in the May 2007 Medical Care 45(5), pp. 448-455.

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