Severe pulmonary barotrauma

Pulmonary barotrauma is a well-known but rarely seen complication of mechanical intermittent positive pressure ventilation. It is thought to be related to raised pressures within alveoli which lead to their eventual rupture and the subsequent development of respiratory embarrassment. Mishaps related to faulty one-way valves in the self-inflating, bag-ventilation devices commonly used in cardiopulmonary resuscitation (CPR) can, although rarely, lead to severe barotrauma. In this report, we describe a case of pulmonary barotrauma that appeared to be related to the "locking" of the "Ambu" bag's one-way valve in the inspiratory position during routine CPR.(Au)

Inspiratory valve malfunction in a circle system: pitfalls in capnography

Capnography is a useful technique in monitoring the integrity of anaesthetic equipment such as the malfunctioning of unidirectional valves in circle system. However, the lack of a precise mechanism in existing capnographs to identify the start of inspiration and the beginning of expiration in the capnograms, makes the analysis of the carbon dioxide waveforms during inspiration difficult and thus results in inaccurate assessement of rebreathing. We report a case where, during the malfunction of the inspiratory unidirectional valve in the circle system, the capnograph failed to detect the presence of substantial rebreathing. Critical analysis of the capnogram recorded during the malfunction revealed that there was substantial rebreathing which was underestimated by the capnograph as it reports only the lowest CO2 concentration rebreathed during inspiration in such abnormal situations.(AU)