title: Submarine 'safe to escape' studies in man.
abstract: The Royal Navy requires reliable advice on the safe limits of escape from a distressed submarine (DISSUB). Flooding in a DISSUB may cause a rise in ambient pressure, increasing the risk of decompression sickness (DCS) and decreasing the maximum depth from which it is safe to escape. The aim of this study was to investigate the pressure/depth limits to escape following saturation at raised ambient pressure. Exposure to saturation pressures up to 1.6 bar (a) (160 kPa) (n = 38); escapes from depths down to 120 meters of sea water (msw) (n = 254) and a combination of saturation followed by escape (n = 90) was carried out in the QinetiQ Submarine Escape Simulator, Alverstoke, United Kingdom. Doppler ultrasound monitoring was used to judge the severity of decompression stress. The trials confirmed the previously untested advice, in the Guardbook, that if a DISSUB was lying at a depth of 90 msw, then it was safe to escape when the pressure in the DISSUB was 1.5 bar (a), but also indicated that this advice may be overly conservative. This study demonstrated that the upper DISSUB saturation pressure limit to safe escape from 90 msw was 1.6 bar (a), resulting in two cases of DCS.
authors.forename: K M
authors.initials: KM
authors.lastname: Jurd
authors.forename: F M
authors.initials: FM
authors.lastname: Seddon
authors.forename: J C
authors.initials: JC
authors.lastname: Thacker
authors.forename: S L
authors.initials: SL
authors.lastname: Blogg
authors.forename: M R D
authors.initials: MR
authors.lastname: Stansfield
authors.forename: M G
authors.initials: MG
authors.lastname: White
authors.forename: G A M
authors.initials: GA
authors.lastname: Loveman
mesh_terms: D000328:Adult; D001273:Atmosphere Exposure Chambers; D001274:Atmospheric Pressure; D001469:Barotrauma / Q000209:etiology*; D002138:Calibration; D003664:Decompression / Q000009:adverse effects / Q000379:methods* / Q000592:standards; D003665:Decompression Sickness / Q000000981:diagnostic imaging / Q000209:etiology*; D004432:Ear, Middle / Q000293:injuries*; D004618:Embolism, Air / Q000000981:diagnostic imaging / Q000209:etiology; D004867:Equipment Design; D006610:High Pressure Neurological Syndrome / Q000209:etiology*; D006801:Humans; D008297:Male; D008889:Military Personnel; D008962:Models, Theoretical; D009784:Occupational Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D012623:Seawater; D013366:Submarine Medicine / Q000295:instrumentation / Q000379:methods*; D014463:Ultrasonography; D006113:United Kingdom