Evaluation of the effects of positive end-expiratory pressure of 12 and 15 on intracranial pressure and dynamic lung compliance in obese patients undergoing laparoscopic cholecystectomy under low flow anaesthesia: A randomized controlled trial.

Laparoscopic cholecystectomy, the minimally invasive removal of the gallbladder, has become  the standard treatment for gallstone disease due to benefits like reduced postoperative pain and  shorter recovery times. However, the creation of pneumoperitoneum—insufflation of carbon  dioxide into the abdominal cavity leads to increased intra-abdominal pressure, which  may subsequently elevate intracranial pressure (ICP) and increase the risk of lung atelectasis.  These changes may be aggravated in obese patients. With our study, we aim to evaluate the positive end expiratory pressure (PEEP) which can be freely applied without causing a significant rise in intracranial pressure and its effects on dynamic lung compliance and hemodynamic parameters. Obese patients aged 18-65 years belonging to ASA physical status 1-2 undergoing general anaesthesia for elective laparoscopic cholecystectomy will be included and patients having Pre-existing neurological conditions affecting ICP, severe respiratory, hepatic, cardiovascular or renal dysfunction , previous history of upper abdominal surgery , pregnant women, acute or chronic eye disease, history of intake of medications affecting ICP will be excluded. Routine PAC will be done and a standard anaesthetic procedure will be followed while applying a PEEP of 12 cm H2O in one group and a PEEP of 15 cm H2O will be applied in the other. Ultrasonography will be used to measure the optic nerve sheath diameter and values of dynamic lung compliance and hemodynamic parameters will be noted from the anaesthesia workstation at predetermined time points. Statistical analysis will be performed by using the SPSS software 25 version and a p-value of <0.05 will be considered statistically significant.