To determine the consistency of the pulmonary vasoconstrictor response to arterial hypoxemia, 6 dogs were anesthetized, intubated, and ventilated for 15 minutes alternatively with air and 10% oxygen gas mixture including nitrous oxide. Catheters
were
placed in the pulmonary artery for measurement of pulmonary artery pressure(PAP), pulmonary capillary wedge pressure (PCWP), and cardiac output (CO) and in the femoral artery for monitoring systemic blood pressure and arterial blood gases.
Arterial
Pco2
and pH were kept at steady levels throughout by ventilating the dogs with animal respiratory so that only the isolated effect of hypoxemia on the pulmonary vasculature was studied.
@ES The results were as follows:
@EN 1. Mean value of arterial pH, PaO2 Pco2 was within range of 7.37±0.01~7.40±0.03, 47.83±1.17~51.67±0.80 mmHg, and 34.57±0.17~37.17±0.75 mmHg respectively throughout the experiment.
2. Pulmonary artery pressure was increased 82% at 1st exposure to arterial hypoxemia and 121% at 6 th one from basic value of 14.33±1.63mmHg(p=0.0000).
3. Pulmonary vascular resistance was also increased 142% and 199% at 1st and 6th exposure to arterial hypoxemia from basic value of 329.68±23.89 dyne. Sec. cm-5(P=0.0000).
4. There was no significant changes in CVP, PCWP, MAP, CO, and heart rate.
With the above results the author recognized that PAP and PVR was markedly increased when arterial hypoxemia occured and agreed that the reason was probably the response of pulmonary vasculature to arterial hypoxemia.
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