Time course and magnitude of ventilatory and renal acid-base acclimatization following rapid ascent to and residence at 3,800 m over nine days
| Autor: | Jack K. Leacy, Brandon Pentz, Sarah A. Hewitt, Scott F. Thrall, Caroline A. Rickards, David P. Burns, Ken D. O'Halloran, Trevor A. Day, Nicholas G. Jendzjowsky, Richard J. A. Wilson, Craig D. Steinback, Glen E. Foster, Britta R.M. Byman, Peter Ondrus, Jordan Bird, Alexandra Skalk |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Renal compensation
medicine.medical_specialty Physiology Acclimatization 030204 cardiovascular system & hematology 03 medical and health sciences 0302 clinical medicine Physiology (medical) Internal medicine Ventilatory acclimatization High altitude Medicine Humans Base (exponentiation) Hypoxia Hypocapnia business.industry Altitude Hypoxia (medical) Effects of high altitude on humans Bicarbonates Time course Cardiology medicine.symptom Acid-base business 030217 neurology & neurosurgery |
| Popis: | Rapid ascent to high altitude imposes an acute hypoxic and acid-base challenge, with ventilatory and renal acclimatization countering these perturbations. Specifically, ventilatory acclimatization improves oxygenation, but with concomitant hypocapnia and respiratory alkalosis. A compensatory, renally-mediated relative metabolic acidosis follows via bicarbonate elimination, normalizing arterial pH(a). The time-course and magnitude of these integrated acclimatization processes are highly variable between individuals. Using a previously-developed metric of renal reactivity (RR), indexing the change in arterial bicarbonate concentration (∆[HCO3-]a; renal response) over the change in arterial pressure of CO2 (∆PaCO2; renal stimulus), we aimed to characterize changes in RR magnitude following rapid ascent and residence at altitude. Resident lowlanders (n=16) were tested at 1,045 m (Day [D]0) prior to ascent, on D2 within 24-hours of arrival, and D9 during residence at 3,800 m. Radial artery blood draws were obtained to measure acid-base variables: PaCO2, [HCO3-]a and pHa. Compared to D0, PaCO2 and [HCO3-]a were lower on D2 (P0.058) and RR (P=0.056) were not detected. As pHa appeared fully compensated on D2 and RR did not increase significantly from D2 to D9, these data demonstrate renal acid-base compensation within 24-hours at moderate steady-state altitude. Moreover, RR was strongly and inversely correlated with ∆pHa on D2 and D9 (r≤-0.95; P |
| Databáze: | OpenAIRE |
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