Ultrasonographic investigation of the effect of positive end-expiratory pressure on the cross-sectional area of the femoral vein

Femoral veins are commonly used as a relatively safe alternative route for central venous cannulation. Several maneuvers are used to increase the cross-sectional area of the vein. In this study, we assessed the effect of positive end-expiratory pressure (PEEP) on the cross-sectional area (CSA) of femoral veins, using ultrasound in adult patients under positive pressure ventilation. All patients received a standardized induction of general anesthesia and intravenous fluid administration. Using ultrasound, the cross-sectional areas of both femoral veins were measured in 57 adult patients in the supine position without PEEP (control) and in the supine position with PEEP of 10 cm H₂O. Mean arterial pressure and heart rate were recorded before and after the application of PEEP at 10 cm H₂O. The application of 10 cm H₂O PEEP significantly increased the CSA of the right femoral vein by 47.6 % and the left femoral vein by 48.4 % (each P < 0.001). Mean arterial pressure decreased by 2.6 mmHg (95 % CI 1.3–3.9; P < 0.001), whereas no significant change in heart rate was observed (P = 0.861). The CSA of the femoral vein is augmented with the application of 10 cm H₂O PEEP in adult patients undergoing positive pressure ventilation.