Measurement of Cross-sectional Area of the Internal Jugular Vein during Ventilation under Anesthesia Using a Portable Ultrasonic Device

We measured the cross-sectional area of the internal jugular vein using a portable ultrasonic device in 50 artificially ventilated patients. Measurement was preformed at end-expiration, end-inspiration and end-inspiration with plateau pressure of 20cm H2O for 3seconds, as well as at three Trendelenburg positions 0, 10, and 20 degrees.1. The cross-sectional area increased from 0.54±0.22cm2 at end-expiration to 0.79±0.26cm2 at end-inspiration, and to 1.18±0.04cm2 at plateau of 20cm2 H2O.2. At the Trendelenburg position of 20 degrees, the cross-sectional area increased to 0.69±0.28cm2 at the end-expiration, and to 0.89±0.32cm2 at the end-inspiration.3. The effect of the Trendelenburg position was smaller than that of positive pressure ventilation.