Comparison of subclavian vein and inferior vena cava collapsibility index in the intensive care unit.

Abstract

Objective: The aim of this study was to evaluate the correlation between changes in the inferior vena cava collapsibility index and subclavian vein collapsibility index in patients undergoing passive leg raising tests in the intensive care unit, considering that respiratory changes affecting the inferior vena cava may similarly affect the subclavian vein.

Methods: This single-center observational study was conducted on patients aged between 18 and 85 years who underwent passive leg raising in the intensive care unit. When the patient was 45° above the bed, the inferior vena cava and subclavian vein were displayed using ultrasonography; subclavian vein collapsibility index and inferior vena cava collapsibility index values were calculated. After the initial values were recorded, passive leg raising was performed, and the initial measurements were repeated. The CI values measured after passive leg raising were subtracted from those calculated before passive leg raising to determine the changes (Δ) in inferior vena cava and subclavian vein collapsibility indices.

Results: The study was conducted with a total of 64 patients. The mean±standard deviation values for ΔIVC-CI% and ΔSCV-CI% variables were found as 8.97±8.89 and 10.31±10.81, respectively. There were no statistically significant differences in values of ΔIVC-CI% and ΔSCV-CI% (p=0.297). In the Bland-Altman plot, because there were only two values exceeding the +1.96 SD and -1.96 SD limits, it can be said that the agreement between ΔIVC-CI% and ΔSCV-CI% was adequate.

Conclusion: ΔSCV-CI% values are compatible and correlated with ΔIVC-CI% values. Inferior vena cava and subclavian vein responded similarly to fluid changes during passive leg raising.