Decompression Sickness Rates in USAF Altitude Chamber Training Before and After Changing the Peak Altitude from 43,000 Feet to 35,000 Feet

Abstract

Each year, many aircrew members undergo altitude chamber training as part of their duty requirements. While necessary to trainees understanding of reduced pressure environments, they do risk developing decompression sickness (DCS). Examining DCS incidence is important in evaluating training safety. In 1998, peak training altitude was decreased from 43,000 feet to 35,000 feet. General opinion, at the time, held that DCS risk would fall as well as DCS incidence. This study evaluated the overall incidence of DCS in trainees before and after the change. Data collected included chamber flight profile, altitude of DCS onset, and severity of symptoms; the data were collected from the AF Form 361 (Chamber Reactor Form). Cases of DCS from 1997-2000 were counted and classified as Type 1 or Type 2. Incidence rates (DCS cases per total exposures) prior to and following the change were calculated. There was no significant difference in the overall DCS incidence rates and there was no significant difference in the incidence rates of Type 1 or Type 2 DCS. The overall relative risk of DCS after the change was 1.3 (p = 0.24), while the relative risk of Type 1 DCS and Type 2 DCS was 1.2 (p = 0.45) and 1.6 (p = 0.30), respectively. Contrary to general opinion, the drop in peak altitude did not affect DCS rates. Explanation lay in the profiles themselves. Profile overlays, profile area-under-the-curve comparisons, and Altitude DCS Risk Assessment Computer analyses found no substantial exposure differences between training profiles, thus validating the DCS incidence rates found. This methodology may well prove useful in creating and/or customizing future altitude chamber training profiles.

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Document Details

Document Type
Technical Report
Publication Date
Oct 23, 2020
Accession Number
AD1116650

Entities

People

  • David C. Johanson
  • Miranda L. Hancock
  • William P. Butler

Organizations

  • 711th Human Performance Wing

Tags

Communities of Interest

  • Biomedical

DTIC Thesaurus Topics

  • Air Force
  • Air Force Personnel
  • Air Force Research Laboratories
  • Altitude
  • Altitude Chambers
  • Computers
  • Decompression
  • Decompression Sickness
  • Governments
  • Information Science
  • Public Health
  • Risk
  • Risk Analysis
  • Statistical Analysis
  • Trainees
  • Training
  • United States

Readers

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  • Mathematics or Statistics
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