[Critical Incident Reporting on medication errors regarding units of measurement and calculations]

Medication safety is an important hot spot of patient safety. This fact prompted the Swiss Patient Safety Foundation to conduct its annual CIRRNET (Critical Incident Reporting & Reacting NETwork) reporting month on the topic of "Units of measurement of medicines and calculation errors in prescription/dispensing (mg, g, mmol etc.)".

During the CIRRNET reporting month 2018, the CIRS (Critical Incident Reporting System) managers of the health institutions participating in CIRRNET forwarded all incident reports on the topic to the CIRRNET database. The archive was also searched for usable reports on the same topic. The reports were analysed according to the type of medication involved (type of application and medication class according to ATC codes), the process stage affected (prescription, preparation, administration and documentation) and the error category.

Of the 110 reports analysed, 27 reports originated directly from the reporting month, 83 reports were additionally extracted from the archive. 67 reports (60 %) concerned intravenously administered medications and analgesics (opioids and non-opioids, such as NSAIDs) were the most frequently affected/involved medication class with 21 reports (18 %). The process step preparation/calculation was the one where most of the errors analysed occurred. With a total of 48 reports (44 %), most of the errors analysed were classified here. Regarding error categories, it becomes apparent that the categories "Derivation of the amount to be administered (volume/number of single doses) from strength or concentration" with 33 (30 %), "Unit of measurement ml - mg" with 20 (18 %) and "Dose/volume per time" with 14 reports (13 %) were reported most frequently.

Errors concerning units of measurement or the calculation of medication have been numerously reported by the CIRRNET institutions. Often, these were cases in which, for example, the volume of a drug to be administered was derived incorrectly. Such calculations are demanding, prone to error and represent a system problem. Therefore, good solution strategies need to be implemented in order to sustainably improve medication safety and thus patient safety.