Preoperative Ultrasound-Guided Internal Branch Block of Superior Laryngeal Nerve Reduces Postoperative Sore Throat Caused by Double Lumen Endotracheal Intubation: A Randomized Trial

BACKGROUND: Postoperative sore throat (POST) is one of the more common side effects of tracheal intubation patients under general anesthesia (GA) after extubation using double-lumen endobronchial tubes (DLTs). The internal branches of the superior laryngeal nerve (SLN) block (iSLNB) have been reported to anesthetize the larynx for airway manipulation (such as awake tracheal intubation) and pain treatment efficiently. We hypothesized that ultrasound-guided iSLNB (US-guided iSLNB) combined with GA would ameliorate the incidence and severity of POST and hoarseness. METHODS: Patients (n = 82) undergoing thoracoscopic resection of pulmonary nodules/lobes/segments with one-lung ventilation (OLV) under GA were randomized into 2 groups depending on whether performed with iSLNB (S group, n = 41) or not (C group, n = 41) under GA. Patients in the S group received US-guided iSLNB bilaterally before surgery. POST and hoarseness were assessed at 2, 6, and 24 hours after surgery. The primary outcome of this study was the incidence of POST at 6 hours after surgery between groups. RESULTS: The overall accumulated incidence of POST was lower in the S goup than in the C group (9/41 vs 20/41; 95% CI, 0.30 [0.11–0.77]; P = .011). The incidence and severity of POST was lower in the S group than in the C group at 2 hours (9/41 vs 20/41; 95% CI, 0.30 [0.11–0.77]; P = .008 and P = .004) and 6 hours after (7/41 vs 17/41; 95% CI, 0.29 [0.10–0.81]; P = .012 and P = .015) surgery. The incidence and severity of POST at 24 hours after surgery was nonsignificant. However, the incidence and severity of hoarseness was comparable between the 2 groups at 2, 6, and 24 hours after surgery. CONCLUSIONS: Preoperative US-guided iSLNB could significantly ameliorate the incidence and severity of POST induced by double-lumen bronchial catheter intubation