A smaller endotracheal tube combined with intravenous lidocaine decreases post‐operative sore throat – a randomized controlled trial

BACKGROUND: Post-operative sore throat (POST) has increasingly been a common clinical complication particularly in thyroid surgery. We conducted a trial to evaluate the effect of non-pharmacological [smaller-sized endotracheal tube (ETT)] combined with pharmacological intervention [lidocaine intravenous (i.v.)] on POST in women undergoing thyroid surgery. METHODS: Two hundred and forty patients scheduled for thyroid surgery were randomly divided into four groups: Group A, ETT size 7.0 with saline; Group B, ETT size 6.0 with saline; Group C, ETT size 7.0 with lidocaine; Group D, ETT size 6.0 with lidocaine. Patients in Groups C and D received i.v. 1.5 mg/kg lidocaine that was filled in syringe up to 10 ml 5 min before induction of anaesthesia; whereas patients in Groups A and B received an equal volume of saline. The incidence and severity of POST were evaluated at 1, 6 and 24 h after tracheal extubation. RESULTS: The highest incidence of POST occurred at 6 h after extubation in all groups. The incidence of POST was significantly lower in Group D compared with Groups A (23% vs. 62%, P < 0.01), B (23% vs. 42%, P = 0.03) and C (23% vs. 43%, P = 0.02) at 6 h after extubation. Group D had significantly decreased severity of POST compared with Groups A, B and C 6 and 24 h after extubation (P < 0.05). CONCLUSION: Use of smaller-sized ETT combined with i.v. lidocaine decreases the incidence and severity of POST in women undergoing thyroid surgery.