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


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
    • "When procedural sedation is contemplated, exhaled carbon dioxide concentration and electrocardiogram monitoring should also be considered (Goodwin et al., 2005). In the mountains, electronic monitoring maybe unreliable or impractical; sensor placement, battery performance, and the normal range of readings at altitude are a few of the factors that disrupt reliability (Luks and Swenson, 2011). In the same situations, managing adverse responses to analgesics and drug combinations can also be challenging. "
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    ABSTRACT: Aims: We aimed to describe evidence-based options for prehospital analgesia, and to offer practical advice to physicians and nonphysicians working in mountain rescue. Methods: A literature search was performed; the results and recommendations were discussed among the authors. Four authors considered a scenario. The final article was discussed and approved by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM) in October 2013. Results and recommendations: Many health care providers fail to recognize, assess, and treat pain adequately. Assessment scales and treatment protocols should be implemented in mountain rescue services to encourage better management of pain. Specific training in assessing and managing pain is essential for all mountain rescuers. Persons administrating analgesics should receive appropriate detailed training. There is no ideal analgesic that will accomplish all that is expected in every situation. A range of drugs and delivery methods will be needed. Thus, an 'analgesic module' reflecting its users and the environment should be developed. The number of drugs carried should be reduced to a minimum by careful selection and, where possible, utilizing drugs with multiple delivery options. A strong opioid is recommended as the core drug for managing moderate or severe pain; a multimodal approach may provide additional benefits.
    High altitude medicine & biology 04/2014; 15(1):8-14. DOI:10.1089/ham.2013.1135 · 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
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