Ultrasound evaluation of central veinsin the intensive care unit:effects of dynamic manoeuvres.

Abstract

To determine: (1) the proportion of small (<5 mm) or thrombosed internal jugular veins (IJV) and femoral veins (FV) in which catheter placement would be difficult without ultrasound guidance; (2) which position increases central vein sizes and may facilitate cannulation of these vessels. Prospective study. Twelve-bed adult medical intensive care unit. Sixty patients (62 +/- 19 years, SAPS II score 36 +/- 17). Ultrasound examinations of the IJV and FV in supine, Trendelenburg (T) and reverse Trendelenburg (Ti) positions. Maximum diameter and cross-sectional area (CSA) were measured. Venous catheter placement would have been difficult (diameter < 5 mm) or even impossible (thrombosis) for 22% of right IJV, 13% of left IJV, 2% of left and 2% of right FV. In the T position, the CSA of the IJV increased (right IJV: 1.7 +/- 1.4 to 2.01 +/- 1.34 cm2, left IJV: 1.18 +/- 0.81 to 1.34 +/- 0.85 cm2; p < 0.05) and theCSA of the FV decreased (right FV: 1.42 +/- 0.61 to 1.22 +/- 0.58 cm2, left FV: 1.51 +/- 0.62 to 1.26 +/- 0.58 cm2; p < 0.05). In the Ti position, the CSA of the IJV decreased (right IJV: 1.7 +/- 1.4 to 1.35 +/- 1.35 cm2, left IJV: 1.18 +/- 0.81 to 0.87 +/- 0.62 cm2; p < 0.05) and the CSA of the FV increased (right FV: 1.42 +/- 0.61 to 1.66 +/- 0.65 cm2, left FV: 1.51 +/- 0.62 to 1.65 +/- 0.68 cm2; p < 0.05). In two-thirds of patients, the right IJV was significantly larger than the left IJV. Ultrasonography should be performed before at least central venous catheter placement to detect the presence of deep vein thrombosis or vessels less than 5 mm in diameter. Some positions increase veins' diameter at least internally, T position increasing IJV size and Ti position increasing FV size.