Improving Sleep at Altitude: A Comparison of Therapies

• Published in: Wilderness & environmental medicine 2011-12, Vol.22 (4), p.316-320
• Main Authors: Rodway, George W., PhD, Edsell, Mark E., MB, ChB, FRCA, Wong, Bob, PhD, Windsor, Jeremy S., MB, ChB
• Format: Article
• Language: English
• Subjects: Acclimatization - physiology; Acetazolamide - administration & dosage; Adult; Altitude; Analysis of Variance; Carbon Dioxide - administration & dosage; Carbon Dioxide - metabolism; Data Interpretation, Statistical; Emergency; Female; Heart Rate - physiology; high altitude; Humans; hypoxia; Male; Middle Aged; Mountaineering - physiology; nocturnal periodic breathing; Oxygen - administration & dosage; Oxygen - metabolism; Oxygen Consumption; Pulmonary Gas Exchange - physiology; Respiratory Function Tests; Sleep - physiology; treatment
• ISSN: 1080-6032; 1545-1534
• DOI: 10.1016/j.wem.2011.07.002

Objective This study aimed to compare 3 treatment modalities during sleep at an altitude of 5300 m to identify strategies for reducing the incidence of periodic breathing at high altitude. Methods Fifteen trekkers, with identical ascent profiles and no signs or symptoms of altitude illness, served as subjects. All study participants arrived at 5300 m after a gradual ascent from 1300 m. On their second night at 5300 m, subjects were randomly assigned (with a computer - based random assignment procedure) to 1 of 4 different treatment groups: control ( n = 4); 1 L/min O2 via a demand system during sleep ( n = 3); 1 L/min O2 /CO2 mix (1.5% CO2 ) via a demand system during sleep ( n = 4); or 125 mg acetazolamide 30 minutes before bedtime ( n = 4). Heart rate, respiration rate, blood oxygen saturation, tidal volume, minute volume, and apnea hypopnea index were measured. Results Upon comparing the 4 groups, there were no statistically significant differences between the variables. One-way analysis of variance indicated a trend toward statistical significance for Sa O2 between groups (F = 2.9, P = .08), and Tukey Honestly Significant Difference (HSD) post hoc tests indicated a trend in the SaO2 difference between the 1 L/min oxygen and control groups ( P = .07). While 1-way analysis of variance suggested no difference for respiratory rate between groups (F = 2.5, P = .1), Tukey HSD indicated a trend in statistical difference of the respiratory rate between 1 L/min O2 and 1 L/min O2 /CO2 mixture ( P = .08). Conclusions These statistical trends found between control and treatment groups indicate that further study is warranted.