Transpulmonary thermodilution technique for cardiac output measurements: single versus double indicator

Introduction

The aim of the study was to compare ITBVI and EVLWI measured by the double indicator (ITBVI_TD, EVLWI_TD) [1] with those estimated by the single indicator technique (ITBVI_ST, EVLWI_ST) [2].

Methods

Thirty-five patients (24 male, 11 female), mean age 49 (10) years, body surface area 1.8 (0.2) m², undergoing liver transplantation (Ltx) were studied. Each patient received a pulmonary artery catheter placed via the right internal jugular vein and a 4 Fr thermistor-tipped fiberoptic catheter for thermal dye dilution inserted into the descending aorta connected to the COLD-Z021 (Pulsion Medical System, Munich, Germany). For the double indicator method, a bolus injection was made with cooled (0–4°C) indocyanine green dissolved in glucose 5% in a concentration of 2 mg/ml, and for the single indicator technique 15 ml cooled normal saline was used. Bland and Altman analysis was used for statistical evaluation.

Results

The mean bias between ITBVI_TD and ITBVI_ST was 8.6 ml/m² with a standard deviation of 61.8 ml/m², and the mean bias between EVLWI_TD and EVLWI_ST was -0.2 ml/kg with a standard deviation of 2.2 ml/kg.

Conclusions

The single transpulmonary thermodilution technique is as accurate as the double indicator method for ITBVI and EVLWI estimation.

Figure 1

Figure 2