Femoral central venous catheter (CVC) versus internal jugular CVC for assessment of haemodynamic parameters by transpulmonary thermodilution using pulse contour cardiac output

Objective

To compare the intrathoracic blood volume index (ITBVI), cardiac index (CI) and extravascular lung water index (ELWI) values in critically ill patients as measured by transpulmonary thermodilution (TPD) with the pulse contour cardiac output (PiCCO) system, using a femoral central venous catheter (CVC) versus conventional measurement using an internal jugular CVC.

Introduction

There is no evidence that the use of femoral venous access, instead of internal jugular venous access, for TPD measurements significantly alters the haemodynamic parameters obtained via PiCCO. We postulate that the ITBVI and ELWI differ significantly depending on the CVC site used.

Design

A prospective, controlled clinical study in an adult critical care unit in a large tertiary-care teaching hospital.

Patients

Five mechanically ventilated patients with sepsis/septic shock (n = 4) and acute liver failure (n = 1). Participants had an internal jugular CVC and femoral CVC or triple-lumen vascath in place as part of routine management, as well as a femoral arterial catheter connected to the Pulsion PiCCO system.

Materials and methods

Haemodynamic parameters were obtained by the TPD technique using bolus injections of 15 ml iced saline solution via the internal jugular and femoral CVCs (order randomly allocated). Bolus injections were performed in < 8 s and all measurements were completed in less than 10 min. Where applicable, haemofiltration was discontinued for the duration of the measurements.

Results

Ten separate sets of paired measurements were obtained from five patients. The paired t test (SPSS 11) indicated that the ITBVI was significantly overestimated by an average of 27% (P < 0.001) when the femoral CVC was used for the injectate. The CI was not affected by the site of the injectate and, in these preliminary results, there was only marginal overestimation of the ELWI (average 12%, P = 0.049) using the femoral CVC.

Conclusions

In critically ill patients the TPD technique with PiCCO using a femoral CVC may not provide as accurate or reliable measures of the ITBVI and possibly the ELWI as conventional measurement with an internal jugular CVC.

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