Paradoxical cerebral air embolism without an intracardiac septal defect. Case report.

Cerebral air embolism occurred in a patient undergoing trigeminal rhizotomy in the sitting position. During the acute episode, a murmur was detected by the Doppler probe and foam was aspirated from the central venous catheter. The patient did not regain consciousness postoperatively, and computerized tomography demonstrated diffuse cerebral infarction. Subsequently, the patient died, and neuropathological examination revealed multifocal discrete infarcts in the gray and white matter with normal intervening brain. No intracardiac septal defects were present. This is the first fully documented case of cerebral air embolism of venous origin in the absence of intracardiac septal defects, and reemphasizes the hazards of operative procedures in the sitting position.