Abstract des Autors

The purpose of this study was to determine the relationship between blood gases and acid-base measurements in arterial, arterialized venous, and venous blood measured simultaneously during short-term maximal exercise. Ten well-trained male cyclists performed a graded maximal exercise test on a cycle ergometer to determine the power output corresponding to their peak oxygen consumption (test I), and a short term maximal test on a cycle ergometer at peak power output (test II). During test II arterial, arterialized venous and venous blood were sampled simultaneously for determination of partial pressures of oxygen and carbon dioxide, pH, bicarbonate (HCO3), base excess (BE), and lactate (La). Except at rest venous and arterialized venous measurements tended to be the same at all sampling intervals, but differed significantly from measurements in arterial blood. BE was the only variable that rendered consistently significant correlations between arterial and arterialized venous blood at each sampling interval. It is concluded that except for base excess, blood gases and acid-base measurements in venous and arterialized venous blood do not accurately reflect values found in arterial blood during short-term maximal exercise. We suggest that these differences may be due in part to clearance by inactive muscle near the sampling site or vasoconstriction at the inactive sampling site.