A Medical Risk Assessment of Pressurized Submarine Escape Training
Abstract
A review of the available literature on injuries attributed to pressurized submarine escape training was undertaken. Additionally, the most recent mortality and morbidity statistics from cooperating nations, which undertake pressurized escape training, was requested, collected and analyzed. Currently, submarine escape training is undertaken in two ways: I) buoyant ascent, in which a buoyancy aid is worn to assist the escaper to the surface and during which controlled exhalation is required to avoid pulmonary overinflation; and 2) hooded ascent, in which the escaper breathes normally from air retained in a hood worn over the head. The maximum safe depth of escape is constrained by the rate at which the central nervous system can clear nitrogen,which it has accumulated during the compression and early part of the ascent. For survivors in an unpressurized submarine, this depth has been demonstrated to be more than 500 feet (152.4m) of sea water. There appears to be a random component to the risk of pulmonary overinflation and, consequently, any form of pressurized training carries some risk of this condition.Injury data were obtained from 11 nations that have conducted, or currently conduct, training from depths ranging from three to more than 100 feet (30.48m). Hooded ascent appears to be the safest technique, with an incident rate of between 0.1 to 0.6 per 1000 escapes and a fatality rate 10 to 50 times lower than that. For each method of escape, there appears to be a trend toward a higher incidence rate with increasing depth. The overall frequency of incidents and the risk of injury to an individual trainee will be reduced by limiting the number of training ascents that are conducted. Medical screening of escape training candidates, with particular reference to lungsize, may further reduce the risk.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 07, 1999
- Accession Number
- AD1189704
Entities
People
- B. K. Stepke
- D. D. Wray
- P. K. Weathersby
- S. J. Ryder
- T. J. R. Francis
Organizations
- Naval Submarine Medical Research Laboratory