Preload index: pulmonary artery occlusion pressure and intrathoracic blood volume monitoring during lung transplantation

Introduction

We analyzed two preload variables, pulmonary artery occlusion pressure (PAOP) and intrathoracic blood volume index (ITBVI), with respect to cardiac index (CIpa), obtained from pulmonary artery catheter (PAC) during lung transplantation. The reproducibility and precision of all transpulmonary single indicator dilution technique (CIart) and CIpa measurements were also evaluated.

Methods

Measurements were made in 48 patients monitored with PAC and with PiCCO System at six specific stages through the study. The relationship between the two different preload variables (PAOP and ITBVI) and the CIpa were analyzed by linear regression. Agreement between CI measurements obtained by PAC and PiCCO system was analyzed using the analysis suggested by Bland and Altman.

Results

Linear regression between ITBVI-CIpa was r² = 0.40 (P < 0.0001) while PAOP poor correlated to CIpa (r² = 0.004) (Figs 1 and 2). Mean bias between CIart and CIpa was 0.15 l min^-1 m^-2(1.37).

Figure 1

Figure 2

Conclusion

ITBVI, rather than PAOP, is a reliable indicator of cardiac preload in patients undergoing lung transplantation.