TY  - JOUR
AU  - Schumacker, Paul T.
A2  - Schumacker, Paul T.
A2  - Suggett, Andrew J.
A2  - Wagner, Peter D.
A2  - West, John B.
DB  - BISp
DP  - BISp
KW  - Blut
KW  - Gasstoffwechsel
KW  - Hypoxie
KW  - Hämoglobinaffinität
KW  - Höhenphysiologie
KW  - Leistungsfähigkeit, körperliche
KW  - Sauerstoffdissoziationskurve
KW  - Sauerstofftransport
KW  - Sportmedizin
KW  - Tierversuch
LA  - eng
TI  - Role of hemoglobin P50 in 02 transport during normoxic and hypoxic exercise in the dog
TT  - Die Rolle des Haemoglobins P50 beim Sauerstofftransport waehrend normoxischer und hypoxischer Belastungen beim Hund
PY  - 1985
N2  - High hemoglobin affinity for 02  could degrade exercise performance in normoxia by lowering mean tissue P02 but could enhance O2 transport in hypoxic exercise by increasing arterial 02 saturation. We measured 02 transport at rest and at graded levels of steady-state exercise in tracheostomized dogs with normal P50 (28.8 +/- 1.8 Torr) and again after P50 was lowered (19.5 +/- 0.7 Torr) by sodium cyanate infusions. Measurements were made during ventilation with room air (RA), 12 02 in N2, or 10 02 in N2. Cardiac output (QT) as a function of 02 consumption (V02) was not altered by low P50 at any inspired 02 fraction. With RA exercise, arterial content (CaO2) and O2 delivery (QT x CaO2) were unchanged at low P50, whereas mixed venous PO2 was reduced at each level of VO2. With exercise in hypoxia, CaO2 and 02 delivery were significantly improved at low P50. Mixed venous PO2 was lower than control during 12 02 but not different from control during 10 02 exercise at low P50. Despite a presumed decrease in tissue PO2 during RA and 12 O2 exercise, exercise performance and base excess decline were not significantly worse than control levels. We conclude that, in canine steady-state exercise, hemoglobin P50 is not an important determinant of tissue 02-extraction capacity during normoxia or moderate hypoxia. In extreme hypoxia, low P50 may help to maintain tissue PO2 by enhancing systemic 02 delivery at each level of QT. Verf.-Referat
SP  - S. 749-757
SN  - 8750-7587
JO  - Journal of applied physiology
IS  - 3
VL  - 59
M3  - Gedruckte Ressource
ID  - PU198702027954
ER  -