Chronic Mountain Sickness

Hurtado, Alberto

doi:10.1001/jama.1942.02830510016004

Cited by 62 publications

(23 citation statements)

References 6 publications

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“…H. M. had signs of an old myocardial infarction and P. T. showed atrial fibrillation, QRS axis oriented to the left and right bundle branch block. All the symptoms and signs de scribed corresponded to those seen in CMP pa tients [7,12,15,19,23].…”

Section: Subjectssupporting

confidence: 54%

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Phlebotomy improves Pulmonary Gas Exchange in Chronic Mountain Polycythemia

Cruz¹,

Díaz²,

Marticorena³

et al. 1979

Respiration

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There is not unanimous agreement in the literature regarding the effects of bleeding on pulmonary gas exchange in polycythemic patients. Spirometry, alveolar-arterial O₂ and CO₂ tension differences, PaO₂ breathing 100% oxygen and carbon monoxide-diffusing capacity were measured before and after 1 week of chronic phlebotomy in 4 chronic mountain polycythemic patients. Studies were carried out at 3,700 m above sea level (P_B = 491 mm Hg). Before phlebotomy, 2 patients showed abnormal spirometry and gas exchange. Only 1 patient had high PaCO₂ and all of them showed low values of PaO₂ breathing oxygen. Phlebotomy improved both spirometry and gas exchange. Improvement in arterial oxygen saturation and PaO₂ could not be attributed to changes in alveolar ventilation, but rather to better distribution of V_A/Q_C ratios since physiological dead space decreased. Our results are similar to those reported in polycythemia vera patients. A significant correlation between the changes in PaO₂ with phlebotomy and the control PaO₂ have been found from 45 polycythemic patients with chronic obstructive pulmonary disease collected from the literature. It is concluded that excessive polycythemia worsened hypoxemia and that phlebotomy improved gas exchange.

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Section: Subjectssupporting

confidence: 54%

“…The arterial oxygen saturations and tensions were decreased as is known to occur in CMP patients [7,12,13,15,19,23]. 3 pa tients had normal PaC02 values for their altitude of residence and 1 was hypercapnic.…”

Section: Resultsmentioning

confidence: 86%

Phlebotomy improves Pulmonary Gas Exchange in Chronic Mountain Polycythemia

Cruz¹,

Díaz²,

Marticorena³

et al. 1979

Respiration

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“…16 However, sea level residence of CMS Andeans eliminates all signs and symptoms of the disease. 17 This suggests that altitude natives of the Andes are not well adapted to their hypoxic environment. Conversely, Ethiopian altitude dwellers are not known to show signs of maladaptation to their native habitat.…”

Section: Discussionmentioning

confidence: 99%

Cerebral Vasodilatation to Exogenous NO Is a Measure of Fitness for Life at Altitude

Appenzeller

Claydon

Gulli

et al. 2006

Stroke

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Background and Purpose-Andean highlanders, unlike Ethiopians, develop chronic mountain sickness (CMS), a maladaptation to their native land. Ambient hypoxia induces NO-mediated vasodilatation. Fitness for life at altitude might be revealed by cerebrovascular responses to NO. Methods-Nine altitude-native men were examined at 3622 and 794 m in Ethiopia and compared with 9 altitude-native Andean men tested at 4338 and 150 m in Peru. We assessed CMS scores, hematocrits, end-tidal pressure of carbon dioxide (P ET CO 2 ), oxygen saturations, and cerebral blood flow velocity (CBV). We evaluated fitness for life at altitude from the cerebrovascular response to an exogenous NO donor. Results-At high altitude, CMS scores and hematocrits were higher in Andeans, and they had lower oxygen saturations.Ethiopians had higher P ET CO 2 at all study sites. At low altitude, saturations were similar in both groups. Responsiveness of the cerebral circulation to NO was minimal in Ethiopians at low altitude, whereas Andeans had a large response. In contrast, at high altitude, Ethiopians showed large responses, and Peruvians had minimal responses. Conclusions-By our measure, high altitude-native Peruvians were well-adapted lowlanders, whereas Ethiopian highlanders were well adapted to altitude life. Environmental pressures were sufficient for human adaptation to chronic hypoxia in Africa but not South America. The mechanisms underlying these differences are unknown, although studies of neurovascular diseases suggest that this may be related to a NO receptor polymorphism. Key Words: altitude Ⅲ nitric oxide Ⅲ cerebral hypoxia Ⅲ cerebrovascular circulation Ⅲ evolution A ltitude is an inhospitable environment for humans, and yet permanent settlements are found at 5100 m. 1 The fall in barometric pressure with increasing altitude in these habitats reduces the availability of oxygen compared with sea level. Therefore, hypoxia in the mountains is inescapable. Ethiopian highlanders are, by some measures, the best adapted for life at altitude, 2 showing no evidence of chronic mountain sickness (CMS), a failure to adapt to altitude that is commonly seen in the high Andes. 3,4 The severity of CMS is inversely related to fitness for survival in the Andes.A key measure of survival in the mountains is the maintenance of optimal oxygen concentrations in all tissues. An adequate blood flow to the brain is essential for maintenance of a proper oxygen supply, and blood flow, in turn, is profoundly affected by changes in oxygen availability. In response to hypoxia, blood vessels, including those in the cerebral circulation, undergo NO-mediated vasodilatation. Inappropriate release of NO with hypoxia has been implicated in some maladaptation syndromes in sojourners to altitude. 5 We hypothesized that cerebrovascular responsiveness to NO donors would predict the ability for adaptation to life at high altitude. To test this proposal, we compared cerebral blood flow velocity (CBV) responses to NO donors in 2 populations: Peruvian native highlanders, who freq...

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“…Nonetheless, the Pronto-7 could be used as a screening tool using alternate hemoglobin cutoffs to screen for individuals who are at risk of having EE. At high altitude, it is well recognized that oxyhemoglobin saturation values are associated with hemoglobin concentrations (Hurtado, 1942. León-Velarde et al, 1994, Peñaloza et al, 2007, Sahota et al, 2013.…”

Section: Figmentioning

confidence: 99%

Noninvasive Assessment of Excessive Erythrocytosis as a Screening Method for Chronic Mountain Sickness at High Altitude

Vyas

Danz

Gilman

et al. 2015

High Altitude Medicine & Biology

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. Noninvasive assessment of excessive erythrocytosis as a screening method for chronic mountain sickness at high altitude. High Alt Med Biol 16:162-168, 2015.-Globally, over 140 million people are at risk of developing chronic mountain sickness, a common maladaptation to life at high altitude ( > 2500 meters above sea level). The diagnosis is contingent upon the identification of excessive erythrocytosis (EE). Current best practices to identify EE require a venous blood draw, which is cumbersome for large-scale surveillance. We evaluated two point-of-care biomarkers to screen for EE: noninvasive spot-check tests of total hemoglobin and oxyhemoglobin saturation (Pronto-7, Masimo Corporation). We conducted paired evaluations of total serum hemoglobin from a venous blood draw and noninvasive, spot-check testing of total hemoglobin and oxyhemoglobin saturation with the Pronto-7 in 382 adults aged ‡ 35 years living in Puno, Peru (3825 meters above sea level). We used the Bland-Altman method to measure agreement between the noninvasive hemoglobin assessment and the gold standard lab hemoglobin analyzer. Mean age was 58.8 years and 47% were male. The Pronto-7 test was unsuccessful in 21 (5%) participants. Limits of agreement between total hemoglobin measured via venous blood draw and the noninvasive, spot-check test ranged from -2.8 g/dL (95% CI -3.0 to -2.5) to 2.5 g/dL (95% CI 2.2 to 2.7), with a bias of -0.2 g/dL (95% CI -0.3 to -0.02) for the difference between total hemoglobin and noninvasive hemoglobin concentrations. Overall, the noninvasive spot-check test of total hemoglobin had a better area under the receiver operating characteristic curve compared to oxyhemoglobin saturation for the identification of EE as measured by a gold standard laboratory hemoglobin analyzer (0.96 vs. 0.82; p < 0.001). Best cut-off values to screen for EE with the Pronto 7 were ‡ 19.9 g/dL in males and ‡ 17.5 g/dL in females. At these cutpoints, sensitivity and specificity were both 92% and 89% for males and females, respectively. A noninvasive, spot-check test of total hemoglobin had low bias and high discrimination for the detection of EE in high altitude Peru, and may be a useful point-of-care tool for large-scale surveillance in high-altitude settings.

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Chronic Mountain Sickness

Cited by 62 publications

References 6 publications

Phlebotomy improves Pulmonary Gas Exchange in Chronic Mountain Polycythemia

Phlebotomy improves Pulmonary Gas Exchange in Chronic Mountain Polycythemia

Cerebral Vasodilatation to Exogenous NO Is a Measure of Fitness for Life at Altitude

Noninvasive Assessment of Excessive Erythrocytosis as a Screening Method for Chronic Mountain Sickness at High Altitude

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