An engineering critical incident: direct current burn from a neuromuscular stimulator

A patient received a third-degree, direct current (DC) burn on the wrist from a neuromuscular stimulator (NMS) that had been modified by a biomedical technician. The event is used to illustrate the accident process, procedures in investigation of engineering-related incidents, and the mechanisms of burns caused by DC. Similar to most industrial accidents, this one had several contributing causes. It demonstrates the need for thorough review and testing of device modifications, the subtle effects of personnel shortages, the dangers of grounded electrosurgical units, and the ways in which seemingly minor features of a device can contribute indirectly to an injury. Accident investigations should be instituted immediately following an event, but care must be taken to ensure that vital information is neither lost nor altered.