Sono-anatomical analysis of right internal jugular vein and carotid artery at different levels of positive end-expiratory pressure in anaesthetised paralysed patients.

Background and Aims: Increasing the cross-sectional area (CSA) of the internal jugular vein (IJV) improves the success rate of cannulation and decreases complications. Application of positive end-expiratory pressure (PEEP) may increase the CSA of IJV beyond that achieved in Trendelenburg position. However, the optimum PEEP to achieve maximal increase in CSA of IJV and the effect of PEEP on IJV and CA relationship is not known.

Methods: In this prospective, blinded, randomised controlled study, 120 anesthetised paralysed patients of the American Society of Anesthesiologists physical Status I-II were placed in 20° Trendelenburg position. Patients were randomised into four groups as follows: PEEP of 0, 5, 10 and 15 cmH2 O. CSA, anteroposterior (AP) diameter and transverse diameter (Td) of IJV and overlapping of IJV with CA were assessed using two-dimensional ultrasound. Statistical analysis was performed in SPSS version 21.0 software using Chi-square/Fisher's exact test (categorical data) and analysis of variance (continuous data) tests and P < 0.05 was considered statistically significant.

Results: There was significant increase in AP diameter, CSA and Td with the application of PEEP 10-15 cmH2 O. Increase in CSA up to 25% with PEEP 10 and 44% with PEEP 15 was noted. There was a significant decrease in the overlapping of the internal CA with an increase in PEEP. It ranged from 21% at P0 to 17% P15.

Conclusion: Application of PEEP 10-15 cmH2 O in Trendelenburg position significantly increased CSA and AP diameter of IJV and decreased CA overlap of IJV in anesthetised paralysed patients.