TY - JOUR
T1 - Breathing in thin air
T2 - Acclimatization to altitude in ducks
AU - Powell, Frank L.
AU - Shams, Hashim
AU - Hempleman, Steven C.
AU - Mitchell, Gordon S.
N1 - Funding Information:
This work was supported by NIH HL-17731, HL-07212 and the University of California, White Mountain Research Station. We thank Glenn Adams, Leslie Hempleman, Pat Martin, Eileen Collins, Alan Fong and Andrew Gray for help with the data collection and analysis. We also thank the staff at WMRS and Drs. Lanphier (deceased) and Lehner at the University of Wisconsin Biotron hypobaric chamber for logistical support. Finally, we thank Peter Scheid for the inspiration to study respiration in birds at altitude.
PY - 2004/12/15
Y1 - 2004/12/15
N2 - We measured ventilation (V̇I) and arterial blood gases in Pekin ducks during acclimatization to 3800 m altitude for 1-90 days. Four experimental series were conducted over 4 years using both natural altitude and a hypobaric chamber. PaCO2 decreased to 3.5 Torr, relative to the value measured during acute hypoxia after 1day and remained at this level for up to 90 days. However, PaO2 did not increase. Arterial pH showed an unexpected metabolic alkalosis during the first hours at altitude but after 3 days, a metabolic acidosis partially compensated the respiratory alkalosis and pHa was constant thereafter. When normoxia was restored after hypoxia, PaCO2 was 5.5 Torr less than the original normoxic control value, but PaO2 was not increased. V̇I showed variable changes during acclimatization but if metabolic rate was constant in our study, as reported by others, then effective parabronchial V̇(V̇P) increased during acclimatization. Increased V̇P tends to restore PaO2 toward normoxic levels and decreases adverse effects of gas exchange limitation, which apparently increased during acclimatization in ducks.
AB - We measured ventilation (V̇I) and arterial blood gases in Pekin ducks during acclimatization to 3800 m altitude for 1-90 days. Four experimental series were conducted over 4 years using both natural altitude and a hypobaric chamber. PaCO2 decreased to 3.5 Torr, relative to the value measured during acute hypoxia after 1day and remained at this level for up to 90 days. However, PaO2 did not increase. Arterial pH showed an unexpected metabolic alkalosis during the first hours at altitude but after 3 days, a metabolic acidosis partially compensated the respiratory alkalosis and pHa was constant thereafter. When normoxia was restored after hypoxia, PaCO2 was 5.5 Torr less than the original normoxic control value, but PaO2 was not increased. V̇I showed variable changes during acclimatization but if metabolic rate was constant in our study, as reported by others, then effective parabronchial V̇(V̇P) increased during acclimatization. Increased V̇P tends to restore PaO2 toward normoxic levels and decreases adverse effects of gas exchange limitation, which apparently increased during acclimatization in ducks.
KW - Acid-base balance, hypoxia
KW - Altitude, ventilatory acclimatization
KW - Birds, duck
KW - Hypoxia, altitude
KW - Methods, plethysmography
KW - Ventilation, hypoxic response
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U2 - 10.1016/j.resp.2004.07.021
DO - 10.1016/j.resp.2004.07.021
M3 - Article
C2 - 15556105
AN - SCOPUS:8844258170
SN - 1569-9048
VL - 144
SP - 225
EP - 235
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
IS - 2-3 SPEC. ISS.
ER -