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Biomedical subjects

Jeremy S Windsor

Publications and source records attributed to Jeremy S Windsor.

5 recordsLinked to original sources

Supplemental oxygen and sleep at altitude.

Windsor, Jeremy S., and George W. Rodway. Supplemental oxygen and sleep at altitude. High Alt. Med. Biol. 7:307-311, 2006.--The purpose of this study was to examine the effect supplemental oxygen has on the respiratory and cardiovascular system of a mountaineer during sleep at high altitude by using a novel ambulatory, multisensor, continuous monitoring device. Supplemental oxygen was administered to a healthy subject via a nasal demand system (0, 16.7, 33.3, or 50 mL/sec per pulse dose delivered over 1 sec) during the first three nights of sleep at 4900 and 5700 m. Increases in pulse dose resulted in a consistent rise in Sa(O(2)) and a fall in minute ventilation (p < 0.05). The 50-mL pulse dose resulted in the greatest changes, with an increase in Sa(O(2)) from 68.5% to 81% (p < 0.05) and a fall in minute ventilation from 13.1 to 10.9 L/min (p < 0.05) being noted. Changes in Sa(O(2)) and minute ventilation also coincided with a fall in apnea/hypopnea index (AHI). At 4900 m the AHI fell from 12.5-52.3 (breathing air) to 0-7.5 (50-mL oxygen pulse), whereas at 5700 m a decrease from 49.1-80.4 to 3.5-10.0 was observed. No changes in respiratory rate or heart rate were identified when different pulse doses were compared (p < 0.05). The multisensor monitoring device proved to be a highly effective system, demonstrating marked improvements in Sa(O(2)), tidal volume, and AHI in our participant when supplemental oxygen was administered via a nasal demand system.

Administration, Intranasal↗

Airway mucociliary function at high altitude.

Despite the presence of a number of anecdotal reports in the mountaineering literature, mucociliary dysfunction at high altitude has received little scientific attention. However, the dry, cold, thin air at high altitude has the potential to undermine normal mucociliary function. This seems increasingly likely in mountaineers who also experience dehydration, nasal obstruction, and extremes of aerobic respiration when climbing in such environments. These factors may result in a number of clinical conditions that range from sore throats and coughs commonly seen at altitude to rarer cases of bronchiolar collapse and lung atelectasis. The purpose of this review is to discuss the etiology of mucociliary dysfunction at altitude and outline a number of potential solutions to the problems this phenomenon presents.

Altitude↗

The use of closed-circuit oxygen in the Himalayas.

Two days before the first ascent of Mt. Everest in 1953, Tom Bourdillon and Charles Evans climbed to within 90 m of the summit at unprecedented speeds. By breathing pure oxygen from a closed circuit, the pair were able to obtain an enormous physiological advantage. Unfortunately, due to a malfunction in Evans's circuit, the pair abandoned their attempt on the South Summit. For many who used the circuit in the 1930s and 1950s, the device proved too heavy, uncomfortable, and tiring for mountaineering. These factors, together with the wider ethical concerns of using supplemental oxygen at altitude, have meant that closed-circuit oxygen has been ignored for more than 50 years. In this article the authors will attempt to describe the history of this discarded circuit and the experience of those who utilized it.

Altitude Sickness↗

Mt. Kellas.

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Expeditions↗