End tidal carbon dioxide monitoring for detection of venous air embolism.

With the aim of defecting the potential hazard of air embolism, end tidal carbon dioxide (ETCO2) was monitored in 238 patients undergoing neurosurgery (in the sitting position), for early detection of venous air embolism (VAE). Fifty six episodes (26.3%) of significant fall in ETCO2 were observed in 41 patients (17.2%). Haemodynamic disturbances occurred in only 26 patients (10.9%) and were always preceded by a fall in ETCO2. Thirteen patients had positive air aspiration and cardiac murmurs were heard in only six. One patient suffered severe hypoxaemia (PaO2 = 55 mm Hg) whereas two had severe haemodynamic disturbances, but could be promptly resuscitated.