[Diagnostic and prognostic significance of hemodynamic and respiratory parameters in venous air embolism].

In 25 patients undergoing neurosurgical operations in the sitting position we investigated the reliability of different continuously monitored haemodynamic and respiratory data for hypoxia, which is the most important alteration for the prognosis of air embolism. Simply referring to characteristic changes of end-tidal carbon dioxide (pCO2E) we were able to establish the diagnosis of venous air emboli in 12 of these patients. Besides a decrease in pCO2E, only the reduction of arterial oxygen concentration was statistically significant. Using a simple regression-test, however, no sufficient correlation between the two parameters could be found. Including pCO2E and haemodynamic data in our statistical comparison, multiple regression revealed an optimal correlation with the decrease in arterial pO2. Pathophysiological effects of air embolism are due to a transient accumulation of air in the pulmonary arterioles. Continuous monitoring of pCO2E is the most direct and therefore most reliable method for detection of pulmonary air emboli. Hypoxia, prognostically the most decisive alteration, develops parallel to the decrease in pCO2E and, being of multifactorial aetiology, is also influenced by haemodynamic effects of air embolism.