Possible strategies to reduce altitude-related excessive polycythemia

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Schmidt, Walter ; Wachsmuth, Nadine ; Romero Pozo, Maria Catarina ; Aguilar Valerio, Martha Teresa ; Contreras Tapia, Ivonee Clorinda ; Vater, Marina ; Kaufmann, Julia ; Jiménez-Claros, Jesus Carlos ; Soria, Rudy:
Possible strategies to reduce altitude-related excessive polycythemia.
In: Journal of Applied Physiology. Bd. 134 (2023) Heft 6 . - S. 1321-1331.
ISSN 1522-1601
DOI: https://doi.org/10.1152/japplphysiol.00076.2023

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Abstract

We sought to determine the effects of three treatments on hemoglobin (Hb) levels in patients with chronic mountain sickness (CMS): 1.) descent to lower altitude, 2.) nocturnal O 2 supply, 3.) administration of acetazolamide. Nineteen CMS patients living at an altitude of 3,940 ±130 m participated in the study, which consisted of a three week intervention phase and a four-week post-intervention phase. Six patients spent three weeks at an altitude of 1,050 m (LAG), six received supplemental oxygen for 12 h overnight (OXG) and seven received 250 mg of acetazolamide daily (ACZG). Hemoglobin mass (Hbmass) was determined using an adapted carbon monoxide (CO) rebreathing method before, weekly during, and four weeks post-intervention. Hbmass decreased by 245±116 g (p<0.01) in the LAG and by 100±38 g in OXG, and 99±64 g in ACZG (p<0.05, each), respectively. In LAG, [Hb] decreased by 2.1±0.8 g/dl and hematocrit by 7.4±2.9 % (both p<0.01), whereas OXG and ACZG only trended toward lower values. Erythropoietin concentration ([EPO]) decreased between 81±12 % and 73±21 % in LAG at low altitude (p<0.01) and increased by 161±118 % five days after return (p<0.01). In OXG and ACZG, the [EPO] decrease was ~75 % and ~50 %, respectively, during the intervention (p<0.01). Descent to low altitude (from 3,940 m to 1,050 m) is a fast-acting measure for the treatment of excessive erythrocytosis in CMS patients, reducing Hbmass by 16 % within three weeks. Nighttime oxygen supplementation and daily acetazolamide administration are also effective, but reduce Hbmass by only 6 %.