[Gas leakage from an anesthetic circuit caused by mis-installation of a canister].

We report a case of gas leakage from an anesthetic circuit, due to mis-installation of a different but very similar canister. A 56-year-old woman was scheduled for a pylogastrectomy. We planned to use a Mera MD757XLV anesthesia machine. At preoperative checking of the anesthetic machine, there was a gas leak from the anesthesia circuit without apparent reasons. We therefore had to use another anesthetic machine, MD705XL, which showed no gas leakage and was used without problems during anesthesia. Closed examination after the operation showed that the gas leakage from the MD757XLV machine occurred, because one of two canisters was wrongly replaced by a canister of MD705XL. The shapes of canisters of these two anesthesia machines look very similar, but there are crucial differences in their specifications, but even the manufacturer did not notice. These unnoticeable differences led to mis-installation of canisters, and one machine provided an airtight seal whereas the other did not. Both manufacturer and users should be aware of this danger.