Medication errors involving patient-controlled analgesia

Purpose. The magnitude, frequency, and nature of nonharmful and harmful medication errors associated with patient-controlled analgesia (PCA) were studied. Methods. A retrospective analysis of Medmarx, a national voluntary medication error-reporting database, was conducted for the period from July 1, 2000, to June 30, 2005, to identify all PCA-related medication errors. Quantitative analysis of the records included the severity of each error, type of error, phase in the medication-use process, principal cause, contributing factors, actions taken, and drug and staff involved. A qualitative analysis was also performed. Results. Over the five-year review period, 919,241 medication errors records from 801 facilities were submitted to Medmarx. Of these, 9,571 (1 %) were associated with PCA. There were 624 records of PCA associated with harm, corresponding to 6.5% of the patients. Errors were reported across all phases of the medication-use process, but the majority occurred during drug administration. Over one third (38%) involved an improper dosage or quantity, while 17.4% involved an omission and 17.3% an unauthorized or wrong drug. Overwhelmingly, human factors were the main cause of PCA errors. Equipment issues (19.5%) and similar drug names and product packaging (11.6%) were also implicated. Distractions (37.8%) and inexperienced staff (26.3%) were the leading contributing factors. Harmful errors required more institutional resources than nonharmful medication errors to manage. Prescribers often issued incomplete, duplicative, or contradictory orders or failed to adjust dosages for comorbid conditions. Dispensing errors were often associated with misfills from the automated dispensing cabinet, compounding of a wrong strength, or lack of drug product availability. Administration errors involved the wrong drug, amount, or concentration, often because the PCA device was misprogrammed. Conclusion. Events during all phases of the medication-use process contributed to PCA-related medication errors, many of which harmed patients.