Pulse Oximetry at High Altitude

Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington 98104, USA.
High altitude medicine & biology (Impact Factor: 1.28). 06/2011; 12(2):109-19. DOI: 10.1089/ham.2011.0013
Source: PubMed

ABSTRACT Pulse oximetry is a valuable, noninvasive, diagnostic tool for the evaluation of ill individuals at high altitude and is also being increasingly used to monitor the well-being of individuals traveling on high altitude expeditions. Although the devices are simple to use, data output may be inaccurate or hard to interpret in certain situations, which could lead to inappropriate clinical decisions. The purpose of this review is to consider such issues in greater detail. After examining the operating principles of pulse oximetry, we describe the available devices and the potential uses of oximetry at high altitude. We then consider the pitfalls of pulse oximetry in this environment and provide recommendations about how to deal with these issues. Device users should recognize that oxygen saturation changes rapidly in response to small changes in oxygen tensions at high altitude and that device accuracy declines with arterial oxygen saturations of less than 80%. The normal oxygen saturation at a given elevation may not be known with certainty and should be viewed as a range of values, rather than a specific number. For these reasons, clinical decisions should not be based on small differences in saturation over time or among individuals. Effort should also be made to minimize factors that cause measurement errors, including cold extremities, excess ambient light, and ill-fitting oximeter probes. Attention to these and other issues will help the users of these devices to apply them in appropriate situations and to minimize erroneous clinical decisions.

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    • "The list of medical problems and medications of the pilgrims needs to be properly written out in legible writing in English, Hindi, or Nepali (as the case may be) which the pilgrims need to carry in person. A simple, hand-held pulse oximeter may be useful in evaluating a pilgrim with the symptoms of altitude illness or to monitor pilgrims with cardiopulmonary problems, although pitfalls in their use need to be noted (Luks and Swenson, 2011). Finally, since pilgrimages are often a family journey, AMS prevention programs should be targeted both at parents and children. "
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    ABSTRACT: Abstract Religious pilgrims have been going to high altitude pilgrimages long before trekkers and climbers sojourned in high altitude regions, but the medical literature about high altitude pilgrimage is sparse. Gosainkunda Lake (4300 m) near Kathmandu, Nepal, and Shri Amarnath Yatra (3800 m) in Sri Nagar, Kashmir, India, are the two sites in the Himalayas from where the majority of published reports of high altitude pilgrimage have originated. Almost all travels to high altitude pilgrimages are characterized by very rapid ascents by large congregations, leading to high rates of acute mountain sickness (AMS). In addition, epidemiological studies of pilgrims from Gosainkunda Lake show that some of the important risk factors for AMS in pilgrims are female sex and older age group. Studies based on the Shri Amarnath Yatra pilgrims show that coronary artery disease, complications of diabetes, and peptic ulcer disease are some of the common, important reasons for admission to hospital during the trip. In this review, the studies that have reported these and other relevant findings will be discussed and appropriate suggestions made to improve pilgrims' safety at high altitude.
    High Altitude Medicine & Biology 10/2014; 15(4). DOI:10.1089/ham.2014.1088 · 1.28 Impact Factor
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    • "Mean value of SaO2 at 4,240 m ranged 87%-87.6% (18), therefore, we chose 87% as a cut-off value in this study. "
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    ABSTRACT: This study was performed to evaluate whether increasing hemoglobin before ascent by prophylactic erythropoietin injections prevents acute mountain sickness (AMS). This open-label, randomized, controlled trial involved 39 healthy volunteers with hemoglobin ≤15.5 g/dL who were divided randomly into erythropoietin (n=20) and control (n=19) groups. Epoetin alpha 10,000 IU injections were given weekly for four consecutive weeks. On day 1, and 7 days after the last injection (day 29), oxygen saturation (SaO2), and hemoglobin were measured. The subjects departed Seoul on day 30 and arrived at Annapurna base camp (ABC, 4,130 m) on day 34. AMS was diagnosed when headache and Lake Louise score (LLS) of ≥3 were present. Immediate descent criteria followed US Army recommendations. Two groups differ in hemoglobin levels on day 29 (15.4±1.1 vs 14.2±1.0 g/dL, P=0.001). At ABC, erythropoietin group had a significantly lower mean LLS, AMS incidence, and number of subjects who met immediate descent criteria. Multiple logistic regression analysis showed that SaO2<87% and control group, but not hemoglobin<15.0 g/dL, independently predicted satisfaction of immediate descent criteria. Erythropoietin-related adverse effects were not observed. In conclusion, erythropoietin may be an effective prophylaxis for AMS.(Clinical Trial Registry Number; NCT 01665781). Graphical Abstract
    Journal of Korean medical science 03/2014; 29(3):416-22. DOI:10.3346/jkms.2014.29.3.416 · 1.27 Impact Factor
    • "Individuals’ SpO2 levels were within the expected range when compared to previous studies examining travelers at similar altitudes.[1516] As the majority of pilgrims traveling to Hemkund Sahib are ethnically Punjabi, it is unlikely that they would have any genetic advantage in maintaining higher SpO2 when trekking through the mountains; unlike, say, the Tibetan people in nearby Himachal Pradesh and Jammu and Kashmir who possibly do.[17] "
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    ABSTRACT: Hemkund Sahib is a popular pilgrimage located at 4,330 m in the Garhwal range of the Indian Himalayas. Many travelers to the region have observed pilgrims exhibiting Acute Mountain Sickness (AMS)-like symptoms. However, no systematic study on its prevalence at Hemkund has been conducted. We surveyed 25 adults. AMS rates were determined using a standard Lake Louise Score (LLS). Responses to questions related to awareness of AMS, the perceived difficulty of the trek, and physiological data including arterial oxygen saturation (SpO2) and pulse rate, amongst others, were collected. Overall prevalence of AMS was 28% (mild AMS 20%, severe AMS 8%). Borg Rating of Perceived Exertion (RPE) was 3.9/10. Water consumption for the 4-5 hour trek to Hemkund was only 0.9 L and 20% of pilgrims consumed no water at all. Nine pilgrims claimed to be aware of AMS although only one had taken prophylactic medication. SpO2 was 82.2 ± 1.2% and pulse rate was 106.5 ± 2.9 bpm (mean ± SEM). There were no differences in non-LLS-related parameters when pilgrims were subdivided by presence or absence of AMS. This pilot study has, for the first time, documented the prevalence of AMS amongst pilgrims to Hemkund Sahib in the Indian Himalayas.
    Indian journal of occupational and environmental medicine 03/2013; 17(1):12-15. DOI:10.4103/0019-5278.116366
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