title: Study Looking at End Expiratory Pressure for Altitude Illness Decrease (SLEEP-AID).
abstract: Lipman, Grant S., Nicholas C. Kanaan, Caleb Phillips, Dave Pomeranz, Patrick Cain, Kristin Fontes, Becky Higbee, Carolyn Meyer, Michael Shaheen, Sean Wentworth, and Diane Walsh. Study Looking at End Expiratory Pressure for Altitude Illness Decrease (SLEEP-AID). High Alt Med Biol 16:154-161, 2015.--Acute mountain sickness (AMS) affects 25%-70% of the tens of millions of high altitude travelers annually, with hypoxia and nocturnal desaturations as major contributing factors. This is the first double blind randomized placebo controlled trial to assess expiratory positive airway pressure (EPAP) for AMS prevention and nocturnal hypoxic events. Healthy adult participants trekking in the Khumbu region of the Himalayas were randomized to a single-use EPAP nasal strip, or a visually identical sham device (placebo) prior to first night sleeping between 4371-4530 m (14,340-14,800 ft). The primary outcome was AMS incidence, measured by Lake Louise Questionnaire (LLQ), with secondary outcomes of AMS severity (by LLQ) and physiologic sleep indices measured by continuous sleep monitor. Intent-to-treat analysis included 219 participants with comparable demographic characteristics, of which 115 received EPAP and 104 placebo. There was no decrease in AMS with EPAP intervention (14% EPAP vs. 17% placebo; p=0.65; risk difference (-)3.15%, 95% CI (-)12.85%-6.56%). While overall AMS severity was not different between groups, EPAP reported decreased incidence of headache (64% vs. 76%; p<0.05, OR 0.51, 95% CI 0.27-0.95) and dizziness (81% vs. 98%; p<0.03, OR 0.29, 95% CI 0.09-0.78). During sleep, EPAP resulted in significant improvements in average peripheral oxygenation (Spo(2)) (80% versus 78%; p<0.01, mean difference=2, 95% CI 0.58-3.63) and a reduced percentage of time below 80% Spo(2) (31% vs. 46%; p<0.03, median difference=16, 95% CI 2.22-28.18). This lightweight and inexpensive EPAP device did not prevent acute mountain sickness, but did reduce the subgroup incidence of headache and dizziness while improving average nighttime peripheral oxygenation.
authors.affiliation: 1 Stanford University School of Medicine , Stanford, California.
authors.forename: Grant S
authors.initials: GS
authors.lastname: Lipman
authors.affiliation: 2 University of Utah , Salt Lake City, Utah.
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Kanaan
authors.affiliation: 3 University of Colorado at Boulder , Boulder, Colorada.
authors.forename: Caleb
authors.initials: C
authors.lastname: Phillips
authors.affiliation: 4 LA County-USC Emergency Medicine Residency , Los Angeles, California.
authors.forename: Dave
authors.initials: D
authors.lastname: Pomeranz
authors.affiliation: 5 Midwestern University Emergency Medicine Residency , Chicago, Illinois.
authors.forename: Patrick
authors.initials: P
authors.lastname: Cain
authors.affiliation: 6 Stanford-Kaiser Emergency Medicine Residency , Palo Alto, California.
authors.forename: Kristin
authors.initials: K
authors.lastname: Fontes
authors.affiliation: 6 Stanford-Kaiser Emergency Medicine Residency , Palo Alto, California.
authors.forename: Becky
authors.initials: B
authors.lastname: Higbee
authors.affiliation: 7 St. Luke's-Roosevelt Emergency Medicine Residency , New York City, New York.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Meyer
authors.affiliation: 6 Stanford-Kaiser Emergency Medicine Residency , Palo Alto, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Shaheen
authors.affiliation: 8 University of Arizona Emergency Medicine Residency , Tucson, Arizona.
authors.forename: Sean
authors.initials: S
authors.lastname: Wentworth
authors.affiliation: 9 University of Utah Medical School , Salt Lake City, Utah.
authors.forename: Diane
authors.initials: D
authors.lastname: Walsh
mesh_terms: D000208:Acute Disease; D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000453:epidemiology / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009390:Nepal; D010100:Oxygen / Q000378:metabolism; D017286:Polysomnography; D011175:Positive-Pressure Respiration; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D010100:Oxygen
keywords: acclimatization; acute mountain sickness; hypobaric hypoxia; pressure support ventilation; sleep at high altitude