Effect of Intravenous Lignocaine Infusion on Intraoperative End Tidal Desflurane Concentration Requirements

Overview

Lignocaine is a local anaesthetic that is widely used in all medical and surgical fields. Many clinical studies have shown that intravenous (IV) lignocaine given in the perioperative period was safe, reduced airway complications, obtunds cough reflex, reduce sore throat, pain, opioid consumption, nausea, length of hospital stay. Multiple animal studies have shown that IV lignocaine was able to lower anaesthetic gas requirements. Desflurane is an anaesthetic gas that has a rapid onset and offset of action. This study aims to evaluate the effect of IV lignocaine infusion on desflurane requirements. Hypothesis of the study is that IV lignocaine infusion reduces desflurane requirements.

All volunteers will be randomly assigned into two groups based on computer generated randomisation tables. Group Lignocaine will receive an IV bolus dose of 1.5 mg/kg of 2% lignocaine HCL diluted up to 10 ml with normal saline in a 10 ml syringe which will be delivered via a syringe pump over a period of 3 min. This is then followed by an IV infusion at the rate of 1 mg/kg/h of 2% lignocaine HCL in a 20 ml syringe which will be administered by another syringe pump. Group Placebo will receive an IV bolus of 10 ml of normal saline over a period of 3 min followed by an IV infusion of an equal volume of normal saline, both of which will be delivered by separate syringe pumps. After induction of anaesthesia, all volunteers will be ventilated with Aisys™ CS² anaesthesia machine. Anaesthesia shall be maintained with desflurane, in 50% oxygen-air balance with a total flow of 1.0 L/min. The end tidal desflurane (Et-Des) concentration will be adjusted to maintain a target BIS of between 40-60. Desflurane and study infusions will be discontinued and estimation of desflurane cost and volume used will be estimated at the end of surgery.