Bain circuit occluded by foreign body.

The purpose of this report is to describe a potentially hypoxic event which occurred during mask induction with the Bain circuit in a healthy. ASA I boy. Failure of induction occurred because a pop-off weight from a bubble bottle was lodged in the elbow connecting the Bain circuit to the mask and prevented gas flow. Pethick and Foëx-Crampton Smith tests of the Bain circuit could also have missed this condition. Such an anaesthetic mishap could occur with any breathing circuit which is re-used. Although there was no serious misadventure, the potential for an hypoxic complication with either intra-venous induction of anaesthesia, or dislodging of the weight into the airway was significant. We conclude that the standard tests of system patency do not ensure safety.