Effect of Blood Ph and CO2 Tension on the Performance of the Heart-Lung Preparation

摘要

When the performance of heart-lung preparations was evaluated by the relationship between stroke work and left atrial pressure, a change of the CO2 content of the inspired air from zero to 10 per cent caused a progressive decrease in performance. The use of HCl or NaHCO3 allowed for changing the pH and pCO2 of the arterial blood separately. Arterial blood pH rather than blood pCO2 appeared to be the decisive factor in mediating this change. Whenever a change of inspired air composition was made in either direction, the new performance level was preceded by a marked overshoot. A fall in arterial pH was accompanied by a slowing of the heart rate. (Author)