Abstract
We examined the effect of systemic hypercapnia on hypoxic pulmonary vasoconstriction during one lung ventilation in five dogs with thoracotomy.
The lung was ventilated with 100% oxygen and systemic arterial carbon dioxyde was controlled by changing the ventilatory rates. Aortic and left pulmonary blood flows are electromagnetically measured. The blockade of the left main bronchus resulted in immediate and sustained decrease in the percent left lung blood flow in 15min; from 36±4% to 13±2% in the group with systemic normocapnia and from 33±3% to 24±2% in the group with systemic hypercapnia.
We conclude that systemic hypercapnia significantly masks the effect of one lung hypoxic pulmonary vasoconstriction.
