Internal mis-mating of breathing system components.

A patient anaesthetized for bronchoscopy could not be ventilated when components of the breathing system met too closely and prevented the out flow of expired gas. This type of obstruction within the system may occur in the Ayre's T-piece, and when "low dead space" mask angles or co-axial systems are used with "low dead space" tracheal connectors or bronchoscopes. The problem is especially dangerous because it is not easily identified and subjects the patient to a very high airway pressure.