Influences observed on incidence and reporting of medication errors in anesthesia

Medication errors are a common occurrence during the conduct of anesthesia (one in 133-450 [corrected] patients). Several factors contribute to medication errors in anesthesia, including experience of the anesthesia provider, severity of comorbidities, and type of procedure. The inexperience of anesthesia providers-in-training also leads to increased error rates. This prospective observational study repeats and extends previous work by Webster et al. and Llewellyn et al. examining the role of comorbidities, type of case, and level of provider experience on the incidence of medication errors.

After Institutional Review Board review and exemption from informed consent, medication error reporting forms were attached to every anesthetic record during a six-month period. All providers were asked to return the forms for every anesthetic, on a strictly voluntary and anonymous basis, and to record the occurrence of medication errors. If providers indicated that a medication error had occurred, additional details about the event were obtained anonymously.

There were 8,777 (83%) responses obtained in a review of 10,574 case forms. A medication error was reported in 35 forms, with an additional 17 forms indicating a medication pre-error or near miss, resulting in 52 (0.49%) errors/pre-errors or a reported incidence of 1:203 anesthetics. Most case types were observed to have a statistically significant increase in reported medication errors. Reported errors by type of anesthesia provider were categorized into anesthesia provider-in-training group and the experienced provider group. The anesthesia provider-in-training group reported a twofold increase in the rate of errors, with the most frequently reported errors being incorrect dose and substitution.

This study suggests that case type, American Society of Anesthesiologists' classification, and level of provider experience play a role on the rate of medication errors. The results of this study are in agreement with previously reported error rates.