Effect Of Positive End-expiratory Pressure On The Cross-sectional Area Of The Internal Jugular Vein And Anatomic Relationship Between The Internal Jugular Vein And The Carotid Artery In General Anaesthesia Of Laryngeal Mask Airway

Objective Aim to investigate the effect of positive end-expiratory pressure?PEEP?on the cross-sectional area?CSA?of the internal jugular vein?IJV?and anatomic relationship between the IJV and the common carotid artery?CCA?in general anaesthesia of laryngeal mask airway?LMA?.Methods 60 American Society of Anesthesiologists?ASA?I or II grade patients undergoing elective operation received general anaesthesia using LMA from May to November 2017,aged 20-65 were included in this study and randomly divided to 4 groups:group P0?PEEP 0 cmH₂O?,group P5?PEEP 5 cmH₂O?,group P10?PEEP 10 cmH₂O?,group P15?PEEP 15 cmH₂O?.After the general anesthesia induction,LMA was inserted,and mechanical ventilation was started while the right cervical vessels was imaged by ultrasonography after applying 4different PEEPs in random order.Measurements were made after 1 min in each PEEP.The CSA,transverse diameter?TD?,anteroposterior diameters?AD?of the IJV and the diameter,overlap distance and overlap index of CCA was measured.The arterial blood pressure,heart rate,and vasoactive drugs used were also recorded.Results There was significant difference in the CSA,TD,AD of IJV among the 4 groups?F=56.90,11.81,17.39,P?0.001?.There was no significant difference in the CSA,TD,AD of IJV between group P0 and P5?P?0.05?.Compared to group P0,the CSA,TD and AD of IJV in group P10and P15 were significantly increased?P0/P10:t=7.81,3.81,4.30,P?0.001,0.01,0.001;P0/P15:t=11.68,5.40,6.96,all P?0.001?.There was no significant difference in the AD and TD of IJV between group P10and P15?P?0.05?,while the CSA of group P15 was bigger than that of group P10?t=2.17,P?0.05?.There was no changes in the diameter of CCA among the 4 groups?F=2.06,P?0.05?.The overlap distance and overlap index among the 4 groups had statistic difference?F=18.33,10.34,P?0.001?.There was no significant difference in the overlap distance and overlap index between group P0 and P5?P?0.05?.Compared to group P0,the overlap distance and overlap index in group P10 and P15 were significantly increased?P0/P10:t=4.49,3.41,P?0.001,0.01;P0/P15:t=5.91,4.63,both P?0.001?.There was no significant changes in the overlap distance and overlap index between group P10 and P15?P?0.05?.There was no statistic difference in the HR among the 4 groups?F=0.68,P?0.05?.The MAP of group P15 was lower than that of group P10?t=2.745,P?0.05?.No patients were given atropine or norepinephrine.Conclusion The application of PEEP effectively increased the CSA of IJV in general anaesthesia of LMA.At the same time,it also led to higher overlap index between the IJV and CCA.10cm H₂O PEEP provided the best balance between the increase of CSA and the stability of haemodynamics.