Intracuff buffered lidocaine versus saline or air – A comparative study for smooth extubation in patients with hyperactive airways undergoing eye surgery

Abstract

Background: Increased cough and restlessness during emergence from general anaesthesia in patients undergoing ophthalmologic surgical procedures might result in increased intraocular pressure, ruptured sutures and suprachoroidal haemorrhage, which can be detrimental to the outcome of surgery. In hyperactive airway patients, as the cough receptors are in the hypersensitised stage, the patients tend to cough more frequently and violently during extubation. Hence, in such patients, we sought to determine the benefits of filling the endotracheal tube cuff with either buffered lidocaine, saline or air, so as to prevent endotracheal tube-induced coughing during emergence from general anaesthesia. Methods: Seventy five patients either with a history of chronic smoking or recently treated upper respiratory tract infections were randomly assigned into three groups (n = 25), based on the type of endotracheal tube cuff inflation, as follows: Group A (air), Group B (6 ml normal saline) and Group C (6 ml 2% lidocaine + 0.5 ml 7.5% sodium bicarbonate). A second, blinded anaesthetist, graded the extubation as: Grade 0 (no cough), Grade 1 (cough < 15s) and Grade 2 (cough > 15s). Results: Extubation was smooth in Group C compared with Groups B and A (p < 0.0001). Further, the incidence of sore throat was found to be lower in both liquid groups, B and C, compared with Group A at 1 h (p < 0.0001) and 24 h
(p < 0.01) postoperatively. Conclusions: Injecting buffered lidocaine into the endotracheal tube cuff, produces smooth extubation even in patients with hyperactive airways as the cough receptors in the tracheal mucosa gets blocked by the increased diffusion of uncharged base form of the drug across the hydrophobic polyvinyl chloride wall of the cuff.