The purpose of this study was to evaluate the impairment of pulmonary gas exchange during the postoperative period after cardiac surgery with CPB in the abscence of chest X ray abnormalities; and to relate these findings with the preoperative pulmonary function status. Therefore four patients with mitral valve disease (group I) and four patients with CAD (group II) were studied through the first 48 postoperative hours by repeated measurement of CO pulmonary hemodynamics (PAP, Pcw), PaO2, D(A-a)O2 and Q(S)/Q(T). Preoperative pulmonary function was significantly impaired in group I, when compared to group II. In face of the postoperative hemodynamic improvement observed in all the patients (greater in group I), pulmonary gas exchange showed a progressive impairment from the 12th to 48th hour. The fall in PaO2 was accompanied by a concurrent widening of D(A-2)O2 in both groups, while the increase in Q(S)/Q(T) was significant in CAD patients only, and highly related to D(A-2)O2. The finding of a lower venous admixture in group I could be explained by a preferential distribution of microatelectasies in the dependent lung zones, chronically underperfused and underventilated in mitral disease patients. D(A-2)O2 seems, therefore, to be a better index of gas exchanges function during the postoperative period in these patients. The observed pulmonary gas exchange impairment could be explained by the association of ventilatory abnormalities due to anaesthesia, surgery and the supine position, with the increase in extravascular lung water due to CPB and hemodilution.

Post-operative course of gas exchange parameters after cardiac surgery on extracorporeal circulation

BUCCA, Caterina;
1982-01-01

Abstract

The purpose of this study was to evaluate the impairment of pulmonary gas exchange during the postoperative period after cardiac surgery with CPB in the abscence of chest X ray abnormalities; and to relate these findings with the preoperative pulmonary function status. Therefore four patients with mitral valve disease (group I) and four patients with CAD (group II) were studied through the first 48 postoperative hours by repeated measurement of CO pulmonary hemodynamics (PAP, Pcw), PaO2, D(A-a)O2 and Q(S)/Q(T). Preoperative pulmonary function was significantly impaired in group I, when compared to group II. In face of the postoperative hemodynamic improvement observed in all the patients (greater in group I), pulmonary gas exchange showed a progressive impairment from the 12th to 48th hour. The fall in PaO2 was accompanied by a concurrent widening of D(A-2)O2 in both groups, while the increase in Q(S)/Q(T) was significant in CAD patients only, and highly related to D(A-2)O2. The finding of a lower venous admixture in group I could be explained by a preferential distribution of microatelectasies in the dependent lung zones, chronically underperfused and underventilated in mitral disease patients. D(A-2)O2 seems, therefore, to be a better index of gas exchanges function during the postoperative period in these patients. The observed pulmonary gas exchange impairment could be explained by the association of ventilatory abnormalities due to anaesthesia, surgery and the supine position, with the increase in extravascular lung water due to CPB and hemodilution.
1982
33
119
131
coronary artery bypass graft; extracorporeal circulation; respiratory system
Costa P.; Bucca C.; Pignatelli M.G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/108570
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