Bubbles and hematologic alterations in intracranial veins during experimental decompression sickness.

Rats were exposed to 6.1 bar (abs.) air for 90 min and subsequently decompressed to the ambient pressure. After a decompression rate of 6.8 bar/min pial veins and superior sagittal sinuses were found to contain gas bubbles; no intravascular bubbles were observed subsequent to a decompression rate of 1.5 bar/min. Under the electron microscope platelet aggregates were observed at both the electron-dense layer of the blood-bubble interface and in pial veins with no bubbles. It is concluded that during decompression sickness bubbles and both activation and aggregation of platelets occur in intracranial veins. Subsequent venous congestion may contribute to the neuronal lesions and symptoms of acute decompression sickness.