ABSTRACT
ObjectiveTo compare the effects of different tidal volumes and positive end expiratory pressures （PEEPs） during mechanical ventilation on the cardiac output of pigs measured by pulmonary artery catheter， transpulmonary thermodilution and pulse contour analysis， and to explore their consistency in cardiac output determination. MethodsTwelve experimental pigs were selected and randomly divided into 3 groups， with 4 pigs in each. Cardiac output was measured by different methods， control group by pulmonary artery catheter， group A by transpulmonary thermodilution and group B by pulse contour analysis. Then we compared the effects of different tidal volumes and PEEPs on the cardiac output of pigs and to explore the consistency. The correlation coefficient between pulse contour analysis and pulmonary artery catheter was r=0.754， and they were positively correlated. The correlation coefficient between transpulmonary thermodilution and pulmonary artery catheter was r=0.771， and they were positively correlated. In determining cardiac output， pulse contour analysis was consistent with pulmonary artery catheter， with a relative error of 13.5% between them； transpulmonary thermodilution was consistent with pulmonary artery catheter， with a relative error of 12.9% between them. The cardiac output decreased significantly along with the increase of tidal volumes or PEEPs and the differences were statistically significant （P<0.05） ConclusionPulmonary artery catheter， transpulmonary thermodilution and pulse contour analysis are well consistent with each other in measuring the cardiac output of pigs. The pigs’cardiac output gradually decreased along with the increase of tidal volumes or PEEPs during mechanical ventilation.