Abstract
Background. End-diastolic volume indices determined by transpulmonary thermodilution and pulmonary artery thermodilution may give a better estimate of left ventricular preload than pulmonary capillary wedge pressure monitoring. The aim of this study was to compare volume preload monitoring using the two different thermodilution techniques with left ventricular preload assessment by transoesophageal echocardiography (TOE). Methods. Twenty patients undergoing elective cardiac surgery with preserved left-right ventricular function were studied after induction of anaesthesia. Conventional haemodynamic variables, global end-diastolic volume index using the pulse contour cardiac output (PiCCO) system (GEDVIPiCCO), continuous end-diastolic volume index (CEDVIPAC) measured by a modified pulmonary artery catheter (PAC), left ventricular end-diastolic area index (LVEDAI) using TOE and stroke volume indices (SVI) were recorded before and 20 and 40 min after fluid replacement therapy. Analysis of variance (Bonferroni-Dunn), Bland-Altman analysis and linear regression were performed. Results. GEDVIPiCCO, CEDVIPAC, LVEDAI and SVIPiCCO/PAC increased significantly after fluid load (P<0.05). An increase >10% for GEDVIPiCCO and LVEDAI was observed in 85% and 90% of the patients compared with 45% for CEDVIPAC. Mean bias (2 sd) between percentage changes (Δ) in GEDVIPiCCO and ΔLVEDAI was −3.2 (17.6)% and between ΔCEDVIPAC and ΔLVEDAI −8.7 (30.0)%. The correlation coefficient (r2) for ΔGEDVIPiCCO vs ΔLVEDAI was 0.658 and for ΔCEDVIPAC vs ΔLVEDAI 0.161. The relationship between ΔGEDVIPiCCO and ΔSVIPiCCO was stronger (r2=0.576) than that between ΔCEDVIPAC and ΔSVIPAC (r2=0.267). Conclusion. GEDVI assessed by the PiCCO system gives a better reflection of echocardiographic changes in left ventricular preload, in response to fluid replacement therapy, than CEDVI measured by a modified PAC
Hofer, C K