The maintenance of life-supporting systems, such as respirators, has been the responsibillity of the central management unit since December 1991. The in-house unit was set up to ensure a high-quality level of maintenance and safety of medical equipment.
We analyzed the incidence of trouble with respirators between 1995 and 1999, based on the logs of the machines and check lists. Fifty-one percent of the incidence was found by medical engineers while they were making their rounds of inspection in the wards, thirty-four percent during periodical checkups at the central safety management unit, and fifteen percent upon request for examination. The faults in warmers and humidifiers attached to the respirators were found only at the wards or upon request for examination. The causes of trouble in the respirators were mechanical failures rather than human error. The mechanical factors was responsible for the incidence 2.9 times as much as human factors. The incidence of trouble associated with the warmers and humidifiers notably dropped after the types of instruments were unified in 1997. To ensure safety, we came to the conviction that the dual check system-the regular inspection at the central safety management unit and the engineers' rounds of inspection-is very effective. The selection of appropriate instruments was also important.