Inadvertent disconnection of the carbon dioxide absorber canister of a Blease Frontline anaesthetic machine

Abstract

We wish to report the recurrent, accidental disengagement of the lever securing the carbon dioxide absorbing canister of a Blease Frontline 560 plus® anaesthetic machine (Blease UK, Chesham, UK) resulting in a leak. Appropriate immediate action and identification of the problem prevented any harm to the patient. On close examination it was found that minimal force was sufficient to disengage the lever from its locked position. We would like to emphasise that the design of the canister makes it very easy for the lever (Fig. 3) to be accidentally knocked from its normal position (securing the absorber canister). The slow, controlled way in which the lever moves from the locked to the fully open position means that the leak may initially be small (not triggering any alarms), before creating a larger leak some time after the lever was knocked – making the detection of the source of the leak more difficult. The locking lever for the carbon dioxide absorber canister assembly of the Blease Frontline 560 plus anaesthetic machine. There are a number of potential solutions to this problem, ranging from a screw type securing mechanism, to a catch securing the lever preventing its inadvertent displacement and subsequent release. However, the most elegant and reliable solutions tend to be the simplest, and a physical guard placed over the lever while in its locked position would prevent any inadvertent displacement. We believe that this should be combined with clear, unambiguous labelling indicating the locked and unlocked position of the lever; a notable absence from the current design. This incident has been reported to the MHRA.