Comparison of the effect of the Trendelenburg and passive leg raising positions on internal jugular vein size in critically ill patients.

Central vein catheterization is a common procedure performed on patients under intensive care. The safe and successful placement of the central venous catheter depends on vein size. Although used for this purpose, the Trendelenburg position can be hazardous in some patients. The aim of this study was to compare the effects of the Trendelenburg and passive leg raising (PLR) positions on the size of the right internal jugular vein (IJV) in mechanically ventilated patients under intensive care. Seventy-eight mechanically ventilated patients under intensive care were included into the study. Sonographic images of the right IJV were recorded in supine (control), 10° Trendelenburg and 40° PLR positions. Anterior-posterior and transverse diameter, cross-sectional area (CSA), and depth were calculated from the recorded images. The size of the right IJV (CSA, transverse and vertical diameters) was significantly larger in the Trendelenburg and PLR positions than in supine position. An increase of 26% in the IJV CSA was obtained in the Trendelenburg position and 23% in the PLR position, compared to the supine position. There was no significant difference between the measurements obtained from the Trendelenburg and PLR positions. The study shows that the Trendelenburg and PLR positions increase the size of the IJV to a similar extent in mechanically ventilated patients under intensive care.