Accession Number:

ADA118923

Title:

The Role of High Pressure and Inert Gases in the Production and Reversal of the High Pressure Neurological Syndrome.

Descriptive Note:

Final rept. 1 Apr 73-31 Mar 82,

Corporate Author:

MASSACHUSETTS GENERAL HOSPITAL BOSTON

Personal Author(s):

• Miller,Keith W.

Report Date:

1982-08-06

Pagination or Media Count:

134.0

Abstract:

The ability of narcotic or anesthetic gases when added to oxy-helium breathing mixtures trimix to increase the depth limit imposed by the high pressure neurological syndrome HPNS has been investigated. Five such gases all gave good protection with potencies related to their anesthetic potencies. A large extension of the safe diving limits can be achieved, but finally a point is reached when the HPNS can only be a further postponed by adding anesthetic levels of the second inert gas. Thus, there now exists a trimix barrier to yet deeper diving. The gas mixtures required to prevent the HPNS can be calculated using as simple model of their mechanism of action called the critical volume hypothesis. These and further studies indicate that the several phases of the HPNS have separate etiologies and it is possible to selectively modify with drugs each of these end points. Neurochemical studies show promise of providing a deeper understanding of the underlying mechanisms. Author

Descriptors:

• *Rare gases
• *Breathing gases
• *Anesthetics
• Oxygen
• Helium
• High pressure
• Neurology
• Deep diving
• Safety
• Limitations
• Mixtures
• Mice

Subject Categories:

• Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE