Hyperbaric Decompression by Means of Bubble Detection.
Abstract
Present decompression procedures, based on the Haldane concept, allow the maximum possible degree of supersaturation without producing decompression sickness in an attempt to provide the greatest rate of gas elimination and the shortest possible safe decompression. The initially large supersaturation values experienced in a Haldane type decompression were shown to predispose bubble formation. Using the Doppler detector implanted on the pulmonary artery or posterior vena cava in sheep and goats, we have demonstrated the presence of gaseous emboli in all Haldane model decompressions. Emboli signals from implanted cuffs were clear with a high signal to noise ratio and were therefore adaptable for signal analysis and absolute quantitation with a gas emboli counter. Gas emboli-free ascent procedures were developed using the ultrasonic detector and the emboli counter. These gaseous emboli when detected in large numbers heralded the onset of decompression sickness. Even in small numbers these emboli caused changes in platelet and fibrinogen survival times. We conclude that the most probable cause of bubble formation in a Haldane type decompression is the initial ascent rate and that gas emboli are pathogenic and should be eliminated to provide a truly safe decompression. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 20, 1978
- Accession Number
- ADA062441
Entities
People
- Kent H. Smith
- Lee Stayton