Performance of emergency underwater breathing systems in cool (25°C) and cold (12°C) water

Research output: Contribution to journalArticle

Original languageEnglish
Pages (from-to)1002-1007
Number of pages6
JournalAviation, Space, and Environmental Medicine
Volume81
Issue number11
DOIs
Publication statusPublished - 2010
Externally publishedYes
Introduction: The shortfall between breath-hold time on cold-water immersion and the time required to make an underwater escape from a helicopter provides the rationale for emergency underwater breathing systems (EUBS) for passengers flying over cold water. This study compared three types of EUBS: a compressed gas system (CG); a rebreather system (RB); and a hybrid system (H). Methods: Each EUBS was examined during water deployment (Wdep) and over 90 s in cool (25°C) and cold water (12°C) immersion to the neck (Imm) and submersion (Subm). Subjects wore standardized clothing, including dry suit. Measures included: Wdep time, stay time (Imm and Subm), dyspnea rating, O2 and CO2 remaining in rebreather bags [H and RB (partial pressure mmHg)], and gas volume used (CG). Results: Mean data show Wdep was slowest in the H (17.7 s) compared to the RB (10.0 s) and CG (8.1 s). Stay time was greatest in the H (90.0 s) compared to the RB (68.3 s) and CG (87.0 s); stay time in CG was also greater than RB. Dyspnea ratings were greater in RB trials (6.5 cm) compared to the CG (2.4 cm) and H (1.9 cm). Across devices, stay time in cold water was shorter during submersion than immersion (85.9 s vs. 70.1 s). During submersion stay time was shorter in cold compared to cool water (12°C: 62.8 s; 25°C: 77.5 s). Discussion: The data suggest that the CG and H devices outperformed the RB device, but the H device required longer to deploy.

    Research areas

  • breath-hold time, cold shock, helicopter underwater escape

External organisations

  • University of Portsmouth

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