Incidence and cardiac effects of systemic venous air embolism. Echocardiographic evidence of arterial embolization via noncardiac shunt.

Central nervous system dysfunction in venous air embolism may result from air entering the arterial circulation. Using two-dimensional and pulsed-wave Doppler echocardiography, this study not only documented the frequent presence of air in the right heart chambers of patients undergoing upright neurosurgery or pacemaker insertion, but also documented the presence of air in the left atrium and left ventricle of one patient via noncardiac shunt. Studies in dogs confirmed paradoxical air embolism in the absence of anatomic communications between right and left heart chambers. Systemic venous air also produced a dose-dependent increase in pulmonary artery pressure and diastolic flattening of the ventricular septum with increase in left ventricular filling pressure despite preserved systolic function.