The changes of pulmonary dead space, shunt and gas exchange after thromboembolism of lungs in swine / 中华急诊医学杂志

ABSTRACT

Objective To investigate the alterations of pulmonary dead space,pulmonary shunt fraction (Qs/Qt) and gas exchange after thromboembolism of lungs in swines and to evaluate the mechanism in respect of pathophysiology and implication.Methods Swine model of pulmonary thromboembolism was made by injection of thrombus into pulmonary artery.Eight swine were used for study of physiologic dead space (VDphy),alveoli dead space (VDalv),airway dead space (VDaw),Qs/Qt,pulmonary arterial pressure (PAP),oxygen partial pressure in arterial blood (PaO2 ),carbon dioxide partial pressure in arterial blood (PaCO2 ),alveolar-arterial O2 gradient (PA-aDO2) determined 30 min before thromboembolism and 0 min,30 min,60 min,120 min after thromboembolism.Results The results showed that VDphy,VDalv,Qs/Qt,PAP,PA-aDO2 increased markedly after thromboembolism in comparison with pre-thromboembolism (P ＜ 0.01 ),while PaO2 declined significantly (P ＜ 0.01 ),and the differences in VDaw and PaCO2 were not significant ( P ＞ 0.05 ).SNK test showed that VDphy and VDalv declined to be smaller at 60 min,120 min than those at 30 min,and PAP declined to be lower at 30 min,60 min,120 min than that at 0 min.Other variables did not change at different intervals after thromboembolism.Hemodynamics did not change significantly after embolization.Conclusions After pulmonary thromboembolism,a various of changes in pathophysiology happened such as increase in dead space,Qs/Qt and PA-aDO2 and decrease in PaO2,but PaCO2 did not change.