Method: the complaint breathing circuit was returned to the manufacturer for evaluation.
The complaint breathing circuit was visually inspected and pressure tested for leaks.
Results: the visual inspection revealed a hole in the expiratory (evaqua) limb, approximately 11cm away from the patient end connector.
The pressure test confirmed the reported leak.
A lot check could not be performed as no lot number was provided.
Conclusion: based on inspection of the damage, it is likely that the evaqua expiratory limb was punctured or scratched by a blunt during use.
The hospital has further reported that they used a drager circuit hanger.
All rt340 breathing circuits are pressure tested for leaks prior to distribution and those that fail are rejected.
This suggests that the breathing circuit was damaged post-production.
The key difference between the evaqua breathing circuits and conventional breathing circuits is that the expiratory tube of evaqua circuits such as the rt340 is composed of a thin, semi-permeable film specially designed to allow water vapour from expired ventilatory gas to pass through.
The evaqua expiratory tube has a protective mesh which prevents damage to the walls of the tube, however the evaqua tubing remains more susceptible to damage than conventional circuits when exposed to rough handling or damage caused by sharp objects and non-fph circuit hangers.
The user instructions supplied with the rt340 breathing circuit state: perform a pressure and leak test on the breathing system and check for occlusions before connecting to a patient; set appropriate ventilator alarms; fit only the supplied fisher & paykel healthcare circuit hanger with care to avoid circuit damage.