Bubbles and hematologic alterations in intracranial veins during experimental decompression sickness

Area of Science:

• Physiology
• Barotrauma Research
• Vascular Biology

Background:

• Decompression sickness (DCS) is a risk in diving and aerospace activities.
• Intracranial venous involvement in DCS is not fully understood.
• Platelet activation is implicated in DCS pathogenesis.

Purpose of the Study:

• To investigate the effect of decompression rate on bubble formation in rat intracranial veins.
• To examine platelet aggregation at the blood-bubble interface and in venous vasculature during DCS.
• To elucidate the role of intracranial venous changes in acute DCS.

Main Methods:

• Rats were exposed to hyperbaric air (6.1 bar absolute) for 90 minutes.
• Subsequent decompression was performed at different rates (6.8 bar/min vs. 1.5 bar/min).
• Intracranial veins and sinuses were examined for gas bubbles; platelet aggregates were analyzed via electron microscopy.

Main Results:

• Rapid decompression (6.8 bar/min) resulted in gas bubbles in pial veins and superior sagittal sinuses.
• Slower decompression (1.5 bar/min) prevented observable intravascular bubbles.
• Electron microscopy revealed platelet aggregates at the blood-bubble interface and within pial veins, even without visible bubbles.

Conclusions:

• Decompression sickness in rats involves intracranial venous gas emboli and platelet activation/aggregation.
• Platelet aggregation occurs independently of visible bubbles in some cases.
• Intracranial venous congestion secondary to these events may contribute to DCS symptoms and neurological lesions.