[Leak test for the internal circuit of anesthesia machines]

In spite of detailed periodic inspection performed by specialized engineers, a great number of anesthesia machines fail to meet the standard of low flow leak test because of leak in the internal circuit. To find out the background and the solution to the problem, we sent questionnaire to 11 major manufacturers and/or dealers each responsible for periodic inspection of anesthetic machines. According to the responses to the questionnaire, the manufacturers and/or the dealers had various methods of internal circuit leak test without a unified standard in detail. The mismatch of the test methods with those anesthesia machines equipped with check valve mechanism has also led to poor evaluation of internal circuit leak. Leak test must be standardized for its appropriate application to work effectively for the problem of leak in the internal circuit of anesthesia machines.