Effects of oxygen administration, bicarbonate infusions, and brief hyperventilation on patients with pulmonary vascular obstructive disease.

Publisher Website
Google Scholar
Abstract
To clarify the mechanisms underlying labile rise in pulmonary vascular resistance, the effects of administering high O2 concentrations, brief voluntary hyperventilation and correction of acidosis were studied in 16 patients in whom congenital heart disease was associated with pulmonary vascular disease. On breathing 100% O2 there was a significant fall in pulmonary vascular resistance from 21.8 .+-. 4.6 to 12.9 .+-. 3.6 units/m2 (P < 0.001), with a rise in pulmonary blood flow from 4.4 .+-. 0.6 to 8.8 .+-. 2.0 l/min per m2 (P < 0.025) and a fall in pulmonary artery pressure from 67.8 .+-. 2.8 to 61.8 .+-. 4.0 mmHg (P < 0.025). The changes occurring on sodium bicarbonate administration in 6 patients did not reach levels of significance, but the size of each individual response was closely correlated with the response to O2 administration. No significant changes occurred on voluntary hyperventilation or, in the systemic circulation, with any intervention. Systemic vascular resistance was positively correlated with pulmonary vascular resistance (P < 0.01). Though age was correlated positively with both pulmonary artery mean pressure (P < 0.025) and vascular resistance (P < 0.025), it was not correlated with the ratio of pulmonary to systemic resistance. Since pulmonary vascular disease is progressive, the validity of resistance ratio as a measure of its severity is doubted.