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

Abstract

and correction ofacidosis werestudied in16patients inwhomcongenital heart disease was associated with pulmonary vascular disease. Onbreathing 100percentoxygenthele was asignificant fall inpulmonary vascular resistance from218± 4.6to12.93-6units/M2 (P< 0.001), with arise inpulmonary blood flow from4-4 ± 0-6to8-8 ± 2-01/min perm2(P< 0025) andafall inpulmonaryartery pressurefrom #67.8 ± 2.8 to618± 40mmHg(P< 0025). Thechanges occurring onsodium bicarbonate adninistra;tion in6patients didnotreach levels ofsignificance, butthesize ofeach individual responsewasclosely correlated withtheresponsetooxygenadministration. Nosignificant changes occurred either on voluntaryhyperventilation or,inthesystemic circulation, with anyintervention. However, systemic vascular resistance waspositively correlated withpulmonary vascular resistance (P< 0.01). Asaresult ofthis, though agewascorrelated positively with both pulmonaryartery mean pressure(P< 0025) andvascular resistance (P< 0.025), itwas notcorrelated withtheratio ofpulmonary tosystemic resistance. Since pulmonaryvascular disease isprogressive, these results castsomedoubt onthevalidity ofresistance ratio asa measureofitsseverity. Patients withcongenital heart disease, particularly whenthisinvolves communications between the pulmonary andsystemic circulations atventricular orgreatarterial level, orconcordant (complete) transposition ofthegreatarteries, areatriskof developing pulmonary vascular obstructive disease. Thisinturnisamajor determinant ofbothimmediateandlate surgical mortality forcorrection ofthe defect (Blount andWoodwark, 1960;Goodwin, 1961; Kirklin, 1965;Cartmill etal., 1966;Mairet al., 1974, 1976). Thedegree ofpulmonary vascular obstructive disease canbeassessed directly before attempted correction bylungbiopsy (Heath etal., 1958b), though this hasdistinct limitations (Adams etal., 1957; Wagenvoort etal., 1967). A promising, butasyetuntested, newtechnique isinhalation and injection ofradioactive nitrogen (13N) (McKenzie