A Prospective Observational Study of Medication Errors in a Tertiary Care Emergency Department

Study objective: We determine the rate and severity of medication errors, as well as factors associated with error occurrence in the emergency department (ED). Methods: This was a prospective observational study conducted between May 1, 2008, and February 1, 2009. The pharmacist observer was present in the ED for 28 shifts (12 hours each). Information was collected on the medication use process by observing the activities of nurses caring for the patients. Errors were categorized by severity. Logistic regression was used to analyze factors associated with a risk of medication error. Results: The observer identified 178 medication errors in 192 patients during the data collection period. At least 1 error occurred in 59.4% of patients, and 37% of patients overall had an error that reached them. No errors in the study resulted in permanent harm to the patient or contributed to initial or prolonged hospitalization; however, interventions were performed to prevent patient harm that likely influenced the severity of error. Errors categorized according to stage were prescribing (53.9%), transcribing (10.7%), dispensing (0.6%), and administering (34.8%). Variables predictive of medication errors were boarded patient status (odds ratio [OR] 2.15; 95% confidence interval [CI] 1.03 to 4.5), number of medication orders (OR 1.25; 95% CI 1.12 to 1.39), number of medications administered (OR 1.22; 95% CI 1.07 to 1.38), and nursing employment status (less error if full time) (OR 0.37; 95% CI 0.16 to 0.86). Conclusion: Medication errors in the ED are common, and most errors occur in the prescribing and administering phases. Boarded patient status, increasing number of medications orders, increasing number of medications administered, and part-time nursing status are associated with an increased risk of medication error.