Effects of Trendelenburg position and positive intrathoracic pressure on internal jugular vein cross-sectional area in anesthetized children

Study Objective: To compare the cross-sectional area (in cm(2)) of the left internal jugular vein (LIJV) and right internal jugular vein (RIJV) In anesthetized children, and measure the response to the Trendelenburg tilt position (TBRG) and a positive inspiratory pressure hold. Design: Prospective, nonrandomized study. Setting: University medical center Patients: 45 ASA physical status I and II children, ages 6 months to 8 years, undergoing general anesthesia and mechanical ventilation. interventions: The cross-sectional area of both internal jugular veins was measured with a 5-MHz, two-dimensional surface transducer at the level of the cricoid cartilage. Three measurements were obtained: I) with the patient supine, 2) during a IO-second breath-hold with a positive inspiratory pressure (PIP) of 20 cm H2O, and 3) with the patient at 20 degrees TBRG. Data were analyzed with two-way analysis of variance (ANOVA) and Student-Newman-Keuls test, with a p < 0.05 considered significant. Measurements and Main Results: In supine patients, the cross-sectional area of the RIJV was larger than the LIJV in 31 patients (69%), and equal or smaller in 14 patients (31%) (0.80 +/- 0.38 vs. 0.59 +/- 0.22; p = 0.002). A PIP hold, but not TBRG, significantly dilated the RIJV(0.8 +/- 0.38 at baseline vs. 0.93 +/- 0.42 with TBRG; p = not significant vs. 1.1 +/- 0.46 with PIP; p < 0.05), whereas neither maneuver was effective with the LIJV. Conclusions: The cross-sectional area of the RIJV is often greater than the LIJV; the TBRG was not effective to increase the cross-sectional area of the internal jugular veins, and only a PIP hold increased significantly the cross-sectional area of the RIJV. In this study, the LIJV appeared of smaller size and less compliant compared with the RIJV. (C) 2001 by Elsevier Science Inc.