SINCE the original report by von Euler and Liljestrand, in 1946, which showed that acute hypoxia increased pulmonary vascular resistance,1 a number of studies in normal subjects have demonstrated the effects of acute hypoxia on pulmonary arterial pressure.2 In most studies 10% oxygen was used resulting in a decrease in arterial oxygen saturation to 75% to 85%. In spite of this severe hypoxic stimulus, mean pulmonary arterial pressure increased but 4 to 8 mm mercury (Hg).2
By contrast, in the subject with a hyperreactive pulmonary vascular bed, maintained by chronic hypoxia, increased pulmonary blood flow, or pulmonary venous hypertension, considerably greater increases in pulmonary arterial pressure have been noted with acute hypoxia. Thus, in a study of high-altitude subjects, ages 13 to 17 years, exposed to the chronic hypoxia of Leadville, Col at 10,150 feet, mean pulmonary arterial pressures increased by as much as 38 mm Hg
Vogel JHK, Kelminson LL, Cotton EK. Pulmonary Hypertension During Sleep. Am J Dis Child. 1967;113(5):576–580. doi:10.1001/archpedi.1967.02090200108011
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