Relationship between positive end-expiratory pressure and internal jugular vein cross-sectional area.

BACKGROUND: Application of positive end-expiratory pressure (PEEP) has been used to increase the cross-sectional area (CSA) of the right internal jugular vein (IJV) in order to facilitate catheterisation. We aimed to determine the PEEP level at which the maximum increase of CSA occurred. METHODS: We enrolled 60 American Society of Anesthesiologists physical status I and II patients undergoing general endotracheal anaesthesia. The CSA was measured in the supine position with no PEEP (control condition, P0) and after applying five different PEEPs in random order: 3 (P3), 6 (P6), 9 (P9), 12 (P12), and 15 (P15) cm H(2) O. Ultrasound was used to measure and record the CSA of the right IJV at the level of the cricoid cartilage. RESULTS: All PEEP levels increased the CSA of the right IJV relative to the control (all P < 0.05). On average, P3, P6, P9, P12, and P15 increased the CSA by 21.5, 37.4, 51.9, 66.5, and 72.4%, respectively. There was no significant increase in CSA above a PEEP of 12 cm H(2) O. CONCLUSION: The application of PEEP effectively increases the CSA of the right IJV. The PEEP giving the largest CSA is 12 cm H(2) O.