Comparative incidence of cardiovascular changes during venous air embolism as detected by transesophageal echocardiography alone or in combination with end tidal carbon dioxide tension monitoring

The objective of our study was to compare the incidences of cardiovascular disturbance during venous air embolism (VAE) episodes detected using transesophageal echocardiography (TEE) and end tidal carbon dioxide (ETCO2) tension monitoring. We retrospectively analyzed the anesthesia records of patients who underwent posterior fossa surgery while in the sitting position and who were simultaneously monitored using both TEE and ETCO2 tension monitoring. Data on the occurrence of VAE and the cardiovascular changes associated with it were recorded. Patients were divided into the ETCO2-positive group (both TEE and ETCO2 tension monitoring indicated VAE) and the ETCO2-negative group (TEE alone indicated VAE, no significant drop in ETCO2). No instances of cardiovascular disturbance were detected in the ETCO2-negative group, whereas the incidences of tachycardia and hypotension were 20% and 30%, respectively, in the ETCO2-positive group. None of the episodes of VAE detected by TEE (without a fall in ETCO2) were clinically significant. We conclude that ETCO2 monitoring is sensitive enough to detect hemodynamically significant VAE episodes.