Objective: To assess the value of quality control tests after routine maintenance procedures of anaesthesia machines.
Study design: Prospective laboratory study.
Material and methods: Over a 4-year-period, anaesthesia machines were checked after regular maintenance procedures, in order to detect unrecognized dysfunctions before clinical use.
Results: Overall 106 tests were performed on 14 machines and five dysfunctions were identified. Three of them concerned gas proportioning devices, which delivered a hypoxic gas mixture (FO2 < 15%). This defect was recognized by gas analysis at their outlet, whereas mechanical controls were satisfactory. The last two concerned pressure relief valve linearity and gas leak at PEEP valve.
Conclusions: This study underlines the necessity of both postmaintenance controls and gas analysis at the outlet of the gas proportioning device. These controls should be performed by hospital technicians, independent from those involved in regular maintenance procedures.