Comparative Evaluation of Laryngeal Mask Airway(LMA) ProSeal LMA, I-gel, Baska Mask and LMA Protector Supraglottic Airway Devices in Adult Laparoscopic Surgeries: A Randomized Controlled Trial

Consent for anaesthesia and participation in the study will be taken. On the day of surgery nil by mouth status of 8 hrs will be confirmed and intravenous cannula will be secured. Aspiration prophylaxis will be given with Inj pantoprazole 40mg and Inj ondansetron 8mg.

Group A- LMA Proseal will be used, Group B – I-gel , Group C – Baska mask and  Group-D – LMA Protector will be used in the operating room, standard monitors will be attached. All the patients will be initially pre - medicated with intravenous Inj. Glycopyrrolate at 0.005mg/kg, Inj. Midazolam at 0.05mg/kg and Inj. Fentanyl at 2mcg/kg. Pre-oxygenation with 100% oxygen will be given for 3 minutes. Anaesthesia will be induced with Inj Propofol 2mg/kg and neuromuscular blockade by Inj Atracurium 0.5mg/kg. Airway device of appropriate size will be inserted in accordance with manufacturer’s recommendation.

Oropharyngeal leak pressure (OLP) will be determined after 5min of insertion of device and 5 min of pneumoperitoneum.

The expiratory valve of the circle system will be closed at a fixed gas flow of 6 Litres per minute and recording the airway pressure at which gas leak occurs by detection of an audible noise by using stethoscope placed just lateral to thyroid cartilage. The ease of insertion will be defined as:

· Very easy : absolutely no resistance

· Easy: no resistance to insertion in the single manoeuvre.

· Difficult: resistances to insertion in the single manoeuvre

· Very difficult: more than one manoeuvre was required for the correct placement of the device. If an effective airway could not be achieved, the device wil be removed and failure of insertion will be recorded and endotracheal intubation will be done.

The duration of insertion will be defined as the time taken from the prepared LMA touching the incisors of the teeth to the successful placement of the device confirmed by square wave capnography, bilateral equal air entry and bilateral chest rise.

Patients will be ventilated at an inspired tidal volume of 6- 8 ml/kg, respiratory rate of 12-14 breaths/minute and an inspiratory: expiratory ratio of 1:2. Anaesthesia will be maintained with 1:1 oxygen-nitrous oxide mixture, Isoflurane (0.6-1%) and inj. Atracurium 0.15 mg/kg (IV) boluses.

Once the procedure is done, the neuromuscular blockade will be reversed with intravenous inj. Glycopyrrolate of dose 0.001mg/kg and inj. Neostigmine of dose 0.05mg/kg. After the return of protective airway reflexes, regain of consciousness, the airway device will be removed and ventilated with facemask for 5 min.