EVALUATION OF THE EFFECT OF DIFFERENT PEEP APPLICATIONS ON OPTIC NERVE SHEATH DIAMETER IN OBESE PATIENTS UNDERGOING LAPAROSCOPIC SURGERY

Abstract

OBJECTIVE: Positive end-expiratory pressure (PEEP) application, which is used to improve oxygenation by keeping the alveoli open, may cause an additional increase in intracranial pressure (ICP) during pneumoperitoneum in obese patients. In this study, the effect of different PEEP applications on the optic nerve sheath diameter (ONSD) in obese patients undergoing laparoscopic surgery was evaluated. MATERIAL AND METHODS: The study included 26 patients with a Body Mass Index (BMI) of ≥ 30 and the American Society of Anesthesiologists (ASA) I-II status undergoing laparoscopic surgery in the reverse Trendelenburg position. After anesthesia induction, the patients were randomly allocated to either the PEEP 5 group or the PEEP 8 group. The patients were compared with respect to age, gender, BMI, ASA status, operations performed, and the hemodynamic data and ONSD values recorded intraoperatively at regular intervals. RESULTS: 22 patients completed the study. Except for gender (p=0.020), there was no difference in demographic and hemodynamic data between the groups. No difference was observed between the groups in respect of ONSD measurements at all times. In the intra-group comparisons, there was no difference in the ONSD values within the PEEP 5 group, whereas in the PEEP 8 group, the measurements at 5 minutes (T2) and 30 minutes (T3) after pneumoperitoneum, and at the end of surgery (T4) were significantly higher than the basal measurements (T1) (p=0.010, p=0.003, p=0.012). CONCLUSIONS: Although PEEP 8 and PEEP 5 applications have similar effects to ICP increase, we thought that it would be safer to apply PEEP increments by measuring ONSD via ultrasonography.