Investigation of correlation between house-staff work hours and prescribing errors

The possible correlation between the frequency and significance of prescribing errors and the number of hours worked during a 24-hour shift by hospital house staff was studied.

A prospective observational trial was conducted in two internal medicine units at an academic medical center. Orders written by medical house staff covering the study units between January 8 and March 10, 2001, were collected daily and evaluated for obvious prescribing errors, the type and significance of the errors, and the number of hours the resident had worked during a 24-hour shift at the time of the prescribing error.

A total of 45,366 orders (including orders for medications, laboratory tests, diagnostic procedures, and nursing care) were entered on the study units during the study period. A total of 498 erroneous prescribing orders were identified. A majority of the erroneous orders (77%) could have resulted in significant morbidity or mortality had they reached the patient. The most common errors involved the wrong dose (18%), the wrong dosage frequency (15%), and duplicate orders (15%). There was no statistically significant correlation between the number of hours worked and the frequency or significance of the errors.

The number of hours worked by medical house staff during a 24-hour shift did not appear to affect the frequency or significance of their prescribing errors.