Impact of misplaced subclavian vein catheter into jugular vein on transpulmonary thermodilution measurement variables.

OBJECTIVE

The subclavian vein (SCV) is usually used to inject the indicator of cold saline for a transpulmonary thermodilution (TPTD) measurement. The SCV catheter being misplaced into the internal jugular (IJV) vein is a common occurrence. The present study explores the influence of a misplaced SCV catheter on TPTD variables.

METHODS

Thirteen severe acute pancreatitis (SAP) patients with malposition of the SCV catheter were enrolled in this study. TPTD variables including cardiac index (CI), global end-diastolic volume index (GEDVI), intrathoracic blood volume index (ITBVI), and extravascular lung water index (EVLWI) were obtained after injection of cold saline via the misplaced SCV catheter. Then, the misplaced SCV catheter was removed and IJV access was constructed for a further set of TPTD variables. Comparisons were made between the TPTD results measured through the IJV and misplaced SCV accesses.

RESULTS

A total of 104 measurements were made from TPTD curves after injection of cold saline via the IJV and misplaced SCV accesses. Bland-Altman analysis demonstrated an overestimation of +111.40 ml/m(2) (limits of agreement: 6.13 and 216.70 ml/m(2)) for GEDVI and ITBVI after a misplaced SCV injection. There were no significant influences on CI and EVLWI. The biases of +0.17 L/(min·m(2)) for CI and +0.17 ml/kg for EVLWI were revealed by Bland-Altman analysis.

CONCLUSIONS

The malposition of an SCV catheter does influence the accuracy of TPTD variables, especially GEDVI and ITBVI. The position of the SCV catheter should be confirmed by chest X-ray in order to make good use of the TPTD measurements.