Comparison of oropharyngeal leak pressure between supraglottic airway devices LMA Protector and I-Gel® in obese patients during laparoscopic cholecystectomy: A randomized control trial.

The study is a randomised control trial regarding the comparison of oropharyngeal leak pressure between supraglottic airway devices (LMA Protector and I Gel®) in obese patients during laparoscopic cholecystectomy.

Obese patients frequently have poorer chest compliance because of their thick chest walls and require higher peak inspiratory pressures when positive pressure ventilation is implemented. Laparoscopic surgeries in obese patients will require higher airway pressure during mechanical ventilation, thus requiring a supraglottic airway device (SAD) with higher oropharyngeal leak pressures (OLP).

Limited research has been conducted to compare the oropharyngeal leak pressure of different supraglottic airway devices, specifically in obese patients undergoing laparoscopic cholecystectomy.  sample size is calculated based on a study by Chang et al. A sample size of 80 (40 per group) will be taken, considering dropouts and errors in sample size calculation. Convenient sampling is done. The primary objective is to compare the oropharyngeal leak pressure LMA Protector and I gel® in obese patients during laparoscopic cholecystectomy. The secondary objective is to evaluate and compare the peak pressure before and after pneumoperitoneum , Fiberoptic glottic views , Insertion attempts , Insertion time , Number and type of airway manipulation , and perioperative and postoperative anesthesia-related problems. The inclusion criteria is obese patients of 18–60 years of age of ASA Physical status I and II planned for elective laparoscopic cholecystectomy under general anesthesia with a BMI of 30 and above. The exclusion criteria includes Patient refusal , Anticipated difficult airway , History of gastroesophageal reflux diseases , Patients with previous abdominal surgery and/or comorbidities that would affect surgical time, time under anaesthesia , Expected duration of surgery > 3 hours; any surgery with expected postoperative ICU admission.

  PPSJ. Patients meeting the inclusion criteria will be shifted to the operating room (OR). Upon arrival inside the OR , all ASA standard monitors will be attached and recording of baseline parameters will be noted. Before inducing the patient, sequentially numbered opaque sealed envelopes with allocated groups will be handed over to the anesthesiologist, and the patient will be induced under general anaesthesia. The appropriate size of SAD will be inserted as per the manufacturer’s guidelines. The OLP will be measured by closing the expiratory valve of the circle system at fresh gas flow of 3 l/minutre and noting the airway pressure at which equilibrium will be reached. Two readings of OLP and peak pressure will be taken: one after insertion and successful placement of SAD (T1), and the other 15 minutes after pneumoperitoneum and reverse trendelenberg position.

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