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DOI

  • Alexander Patrician
    University of British Columbia
  • Michael M Tymko
    University of British Columbia
  • Hannah G Caldwell
    University of British Columbia
  • Connor A Howe
    University of British Columbia
  • Geoff B Coombs
    University of British Columbia
  • Rachel Stone
    University of British Columbia
  • Allison Hamilton
    University of British Columbia
  • Ryan L Hoiland
    University of British Columbia
  • Philip N Ainslie
    University of British Columbia

We examined the hypothesis that an expiratory resistance mask containing a small amount of dead space (ER/DS) would reduce the apnea-hypopnea index (AHI) during sleep, attenuate the severity of acute mountain sickness (AMS), and offset decrements in cognitive function compared with a sham mask. In a double-blinded, randomized, sham-controlled, crossover design, 19 volunteers were exposed to two nights of normobaric hypoxia (FIO2 = 0.125), using a ER/DS mask (3.5 mm restrictive expiratory orifice; 125 mL DS volume) and sham mask (zero-flow resistance; 50 mL DS volume). Cognitive function, AMS, and ventilatory acclimatization were assessed before and after the 12-hour normobaric hypoxia exposure. Polysomnography was conducted during sleep. AHI was reduced using the ER/DS sleep mask compared with the sham (30.1 ± 23.9 events·hr-1 vs. 58.9 ± 34.4 events·hr-1, respectively; p = 0.01). Likewise, oxygen desaturation index and headache severity were reduced (both p < 0.05). There were also benefits on limiting the hypoxia-induced reductions in select measures of reaction speed and attention (p < 0.05). Our study indicates that a simple noninvasive and portable ER/DS mask resulted in reductions (49%) in AHI, and reduced headache severity and aspects of cognitive decline. The field applications of this ER/DS mask should be investigated before recommendations can be made to support its benefit for travel to high altitude.

Keywords

  • Acclimatization/physiology, Adult, Altitude, Altitude Sickness/physiopathology, Cognition/physiology, Cross-Over Studies, Double-Blind Method, Exhalation/physiology, Female, Humans, Hypoxia/physiopathology, Male, Masks, Middle Aged, Respiratory Dead Space/physiology, Sleep/physiology
Original languageEnglish
Pages (from-to)61-70
Number of pages10
JournalHigh Altitude Medicine and Biology
Volume20
Issue number1
DOIs
Publication statusPublished - Mar 2019
Externally publishedYes
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