Wilderness Medical Society Clinical Practice Guidelines for the Prevention, Diagnosis, and Treatment of Acute Altitude Illness: 2024 Update.

To provide guidance to clinicians about best practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention, diagnosis, and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches for managing each form of acute altitude illness that incorporate these recommendations as well as recommendations on how to approach high altitude travel following COVID-19 infection. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine in 2010 and the subsequently updated WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2014 and 2019.

Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2019 Update.

To provide guidance to clinicians about best preventive and therapeutic practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. Recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each form of acute altitude illness that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in 2010 and subsequently updated as the WMS Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness in 2014.

Wilderness Medical Society Clinical Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2019 Update.

To provide guidance to clinicians, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and a balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is the 2019 update of the Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia: 2014 Update.

Risk Stratification for Athletes and Adventurers in High-Altitude Environments: Recommendations for Preparticipation Evaluation.

High-altitude athletes and adventurers face a number of environmental and medical risks. Clinicians often advise participants or guiding agencies before or during these experiences. Preparticipation evaluation (PPE) has the potential to reduce risk of high-altitude illnesses in athletes and adventurers. Specific conditions susceptible to high-altitude exacerbation also important to evaluate include cardiovascular and lung diseases. Recommendations by which to counsel individuals before participation in altitude sports and adventures are few and of limited focus. We reviewed the literature, collected expert opinion, and augmented principles of a traditional sport PPE to accommodate the high-altitude wilderness athlete/adventurer. We present our findings with specific recommendations on risk stratification during a PPE for the high-altitude athlete/adventurer.

Risk Stratification for Athletes and Adventurers in High-Altitude Environments: Recommendations for Preparticipation Evaluation.

High-altitude athletes and adventurers face a number of environmental and medical risks. Clinicians often advise participants or guiding agencies before or during these experiences. Preparticipation evaluation (PPE) has the potential to reduce risk of high-altitude illnesses in athletes and adventurers. Specific conditions susceptible to high-altitude exacerbation also important to evaluate include cardiovascular and lung diseases. Recommendations by which to counsel individuals before participation in altitude sports and adventures are few and of limited focus. We reviewed the literature, collected expert opinion, and augmented principles of a traditional sport PPE to accommodate the high-altitude wilderness athlete/adventurer. We present our findings with specific recommendations on risk stratification during a PPE for the high-altitude athlete/adventurer.

Wilderness Medical Society practice guidelines for the prevention and treatment of acute altitude illness: 2014 update.

To provide guidance to clinicians about best practices, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for prevention and treatment of acute mountain sickness, high altitude cerebral edema, and high altitude pulmonary edema. These guidelines present the main prophylactic and therapeutic modalities for each disorder and provide recommendations about their role in disease management. Recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to prevention and management of each disorder that incorporate these recommendations. This is an updated version of the original WMS Consensus Guidelines for the Prevention and Treatment of Acute Altitude Illness published in Wilderness & Environmental Medicine 2010;21(2):146-155.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia.

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update.

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is an updated version of the original Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia published in Wilderness & Environmental Medicine 2014;25(4):425-445.

High altitude renal syndrome (HARS).

More than 140 million people live permanently at high altitude (>2400 m) under hypoxic conditions that challenge basic physiology. Here we present a short historical review of the populating of these regions and of evidence for genetic adaptations and environmental factors (such as exposure to cobalt) that may influence the phenotypic responses. We also review some of the common renal physiologic responses focusing on clinical manifestations. The frequent presentation of systemic hypertension and microalbuminuria with relatively preserved GFR coupled with the presence of polycythemia and hyperuricemia suggests a new clinical syndrome we term high altitude renal syndrome (HARS). ACE inhibitors appear effective at reducing proteinuria and lowering hemoglobin levels in these patients.

End-tidal partial pressure of carbon dioxide and acute mountain sickness in the first 24 hours upon ascent to Cusco Peru (3326 meters).

OBJECTIVE: To explore the association of end-title partial pressure (Petco(2)) and oxygen saturation (Spo(2)) with the development of AMS in travelers rapidly ascending to Cusco, Peru (3326 m). METHODS: Using the 715 TIDAL WAVE Sp handheld, portable capnometer/oximeter, we measured Spo(2) and Petco(2) in 175 subjects upon ascent to Cusco, Peru (3326 m) from Lima (sea level) (a mean time of 3.9 hours.) Symptoms of AMS were recorded at the same initial time on arrival to altitude and 24 hours later using the Environmental Symptoms Questionnaire (ESQ). RESULTS: This study showed that no subjects with the lowest Petco(2) of 23 to 30 mm Hg had AMS (P <.044). The data also demonstrate that subjects with a higher Petco(2) (36-40 mm Hg) and lower Sao(2) (72%-86%) have a higher incidence of AMS. CONCLUSION: The most important finding of this study is that Petco(2) upon ascent was found to have a more significant effect than Spo(2) on a subject's ultimate ESQ score. This study demonstrates that those individuals with a brisk ventilatory response upon ascent to moderate altitude, as measured by Petco(2), did not develop AMS, whereas a blunted ventilatory response, as reflected in the highest Petco(2), was related to the subsequent development of AMS.

Wilderness Medical Society consensus guidelines for the prevention and treatment of acute altitude illness.

To provide guidance to clinicians about best practices, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the prevention and treatment of acute mountain sickness (AMS), high altitude cerebral edema (HACE), and high altitude pulmonary edema (HAPE). These guidelines present the main prophylactic and therapeutic modalities for each disorder and provide recommendations for their roles in disease management. Recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens according to criteria put forth by the American College of Chest Physicians. The guidelines also provide suggested approaches to the prevention and management of each disorder that incorporate these recommendations.

Illnesses at high altitude.

High-altitude illnesses have profound consequences on the health of many unsuspecting and otherwise healthy individuals who sojourn to high altitude for recreation and work. The clinical manifestations of high-altitude illnesses are secondary to the extravasation of fluid from the intravascular to extravascular space, especially in the brain and lungs. The most common of these illnesses, which can present as low as 2,000 m, is acute mountain sickness, which is usually self-limited but can progress to the more severe and potentially fatal entities of high-altitude cerebral edema and high-altitude pulmonary edema. This article will briefly review normal adaptation to high altitude and then more extensive reviews of the clinical presentations, prevention, and treatments of these potentially fatal conditions. Research on the mechanisms of these conditions will also be reviewed. A better understanding of these disorders by practitioners will lead to improved prevention and rational treatment for the increasing number of people visiting high-altitude areas around the globe. There will not be space for writing about high-altitude residents, medical conditions in low-altitude residents going to high altitude, or training for athletes at high altitude. These topics deserve another article.

A patient with vanishing lung syndrome and remarkable tolerance to high altitude.

Very little information is known about patients with chronic obstructive pulmonary disease who travel to high altitude for work or pleasure. Even less is known about the outcomes at high altitude for patients with severe bullous lung disease. We present the case of a 54-yr-old man with vanishing lung syndrome, an idiopathic form of severe bullous emphysema, who has made repeated trips to altitudes as high as 3400 m, where he has engaged in physical activity, such as downhill skiing. We consider the issues of adequacy of oxygenation and the risks of barotrauma in patients with obstructive lung disease traveling to high altitude, and we also consider factors, such as improved air-flow limitation, maintenance of adequate ventilation-perfusion matching, and underlying physical fitness, which may affect our patient's ability to tolerate physical activity in this environment. The case demonstrates that the presence of severe lung disease does not necessarily preclude travel to and moderate activity at high altitude. Such travel may, in fact, be safe as long as the patient has undergone appropriate pretravel evaluation, and we provide recommendations regarding such evaluation in patients with chronic obstructive pulmonary disease.

Acetazolamide and N-acetylcysteine in the treatment of chronic mountain sickness (Monge's disease).

Patients suffering from chronic mountain sickness (CMS) have excessive erythrocytosis. Low -level cobalt toxicity as a likely contributor has been demonstrated in some subjects. We performed a randomized, placebo controlled clinical trial in Cerro de Pasco, Peru (4380m), where 84 participants with a hematocrit (HCT) ≥65% and CMS score>6, were assigned to four treatment groups of placebo, acetazolamide (ACZ, which stimulates respiration), N-acetylcysteine (NAC, an antioxidant that chelates cobalt) and combination of ACZ and NAC for 6 weeks. The primary outcome was change in hematocrit and secondary outcomes were changes in PaO2, PaCO2, CMS score, and serum and urine cobalt concentrations. The mean (±SD) hematocrit, CMS score and serum cobalt concentrations were 69±4%, 9.8±2.4 and 0.24±0.15µg/l, respectively for the 66 participants. The ACZ arm had a relative reduction in HCT of 6.6% vs. 2.7% (p=0.048) and the CMS score fell by 34.9% vs. 14.8% (p=0.014) compared to placebo, while the reduction in PaCO2 was 10.5% vs. an increase of 0.6% (p=0.003), with a relative increase in PaO2 of 13.6% vs. 3.0%. NAC reduced CMS score compared to placebo (relative reduction of 34.0% vs. 14.8%, p=0.017), while changes in other parameters failed to reach statistical significance. The combination of ACZ and NAC was no better than ACZ alone. No changes in serum and urine cobalt concentrations were seen within any treatment arms. ACZ reduced polycythemia and CMS score, while NAC improved CMS score without significantly lowering hematocrit. Only a small proportion of subjects had cobalt toxicity, which may relate to the closing of contaminated water sources and several other environmental protection measures.

Limits of respiration at high altitude.

Under most conditions, the lungs compensate for the stresses of illness to ensure adequate acquisition of oxygen. Even with exposure to high altitude, the lungs' adaptations ensure that this process takes place. This process is challenged by global hypoxia, especially if there is impairment in the three processes needed for adequate tissue oxygenation: (1) intact ventilatory drive to breathe; (2) sufficient increase in alveolar ventilation, which is stimulated by that drive; and (3) intact gas exchange at the alveolar-capillary interface. This article reviews the mechanisms that make the study of high altitude relevant to patients who have heart or lung disease at low altitude.