Haemodynamic parameters obtained by transthoracic echocardiography and Swan-Ganz catheter: a comparative study in liver transplant patients.

Abstract

To compare the haemodynamic measurements of cardiac output (CO), central venous pressure (CVP), pulmonary capillary wedge pressure (Pw) and pulmonary artery systolic pressure (PASP), obtained by Swan-Ganz catheter and transthoracic echocardiography.Prospective study in a Medical/Surgical Intensive Care Unit (ICU). A total of 41 post liver transplant patients were enrolled. CO, CVP, Pw and PASP, were simultaneously determined by two independent observers, utilizing a Swan-Ganz catheter and transthoracic echocardiography, using equations described in the literature. A linear correlation and a Bland-Altman analysis were performed.A good correlation between invasive and non- invasive measurements for CO (r=0.97) and CVP (r=0.88) was found, but determinations of Pw (r=0.41) and PASP (r=0.18) did not correlate well. Bias and 95% confidence interval for CO were negligible namely when a CO<6 l/min was considered. Pulsed-wave Doppler-echocardiography underestimates the CO when compared with thermodilution, but the 2 techniques agree on average and can be used interchangeably.The non-invasive determination of CO in critical care post liver transplant patients correlates well with the invasive determinations. Transthoracic echocardiography was not appropriate for calculating filling parameters studied. Although the data was obtained in post liver transplant patients, they could be useful in defining the role of echocardiography in the ICU.