Effect of lumbar elevation on dilatation of the central veins in normal subjects

Increasing the size of the central veins is required to increase the success rate of central line placement and decrease complication risk. Right-sided approach for the central veins, Valsalva maneuver, and Trendelenburg position have been recommended, but these may not be available for some cases. This study aimed to determine a more convenient patient position that can result in the largest central vein diameter.

Recruited subjects were placed in 60° and 30° upper body elevation, supine position, and 30° and 60° lower body elevation, and lumbar elevation (LE) was consecutively performed, with one position maintained for 10 min. Diameters of the subclavian vein (SCV) and internal jugular vein (IJV) were measured using high-resolution two-dimensional ultrasonography at each position.

The most suitable position on the ordinary bed for increasing central vein diameter was LE. The maximum and minimum SCV and IJV diameters in LE were significantly larger than those in the supine position (SCV: coefficients -0.633 and -0.863, p = 0.08 and 0.011, respectively; IJV: coefficients -1.09 and -1.15, p < 0.001 and = 0.001, respectively). Leg elevation for 10 min failed to dilate the central vein diameter.

The LE without leg elevation produced a greater and more significant increase in central vein diameter than the supine position and may be useful for central line placement.