Decompression profile and bubble formation after dives with surface decompression: experimental support for a dual phase model of decompression.

The present study was initiated in order to determine the effect of decompression profiles on bubble formation following surface decompression using oxygen. Following an air dive to 496 kPa (130 fsw) for 90 minutes, three different profiles were tested in the pig; a USN staged decompression profile, a profile using linear continuous decompression with the same total decompression time as the USN profile (ABI) and a linear profile with half the total decompression time compared to the the first two (ABII). The subsequent surface decompression at 220 kPa lasted 68 minutes for all three schedules.

Microdialysis in cisterna magna during cerebral air embolism in swine.

Arterial gas embolism may occur as a consequence of lung rupture, decompression sickness, following operative procedures or as accidental infusion of gas during various diagnostic procedures. It can lead to severe morbidity or even death. Microdialysis is a technique that has been extensively used for evaluating localized changes in the brain.

Endothelial damage by bubbles in the pulmonary artery of the pig.

A method for measuring endothelial damage caused by decompression was developed for vessels with a large radius. Segments of the pulmonary artery from pigs (8-12 wk old) were tested for endothelium damage using a system for recording changes in the tension in the vessel wall. Substance P (SP) was used as an endothelial-dependent dilation agonist.

Effect of oxygen tension and rate of pressure reduction during decompression on central gas bubbles.

Reduction in ascent speed and an increase in the O2 tension in the inspired air have been used to reduce the risk for decompression sickness. It has previously been reported that decompression speed and O2 partial pressure are linearly related for human decompressions from saturation hyperbaric exposures. The constant of proportionality K (K = rate/partial pressure of inspired O2) indicates the incidence of decompression sickness.