Compound chamomile and lidocaine hydrochloride gel for postoperative sore throat after nasotracheal intubation: a randomized controlled trial

The incidence of postoperative sore throat (POST) following nasotracheal intubation ranges from 21 to 65%. Despite possessing anti-inflammatory and analgesic properties, the efficacy of Compound Chamomile and Lidocaine Hydrochloride Gel (CCLH-Gel) in relieving POST remains unproven. We hypothesized that CCLH-Gel applied to the endotracheal tube would reduce the incidence and severity of POST compared with a placebo gel. In this prospective, single-center, assessor-blind, randomized, placebo-controlled, superiority trial conducted at West China Hospital of Stomatology, Sichuan University (August 2025–April 2026), 140 patients undergoing bilateral temporomandibular joint (TMJ) surgery were randomly assigned to receive either CCLH-Gel ( n = 70) or plain gel without active ingredients (PL-Gel, n = 70) applied to the surface of the endotracheal tube for nasotracheal intubation. The gel was applied using a standardized two-step technique: first to the cuff and distal tip of the tube before insertion, and then under direct vision via video laryngoscopy after the tube was advanced through the nasal orifice into the hypopharynx. The primary outcome was the incidence of moderate-to-severe POST (Numerical Rating Scale [NRS] ≥ 4) at 3 h postoperatively. Secondary outcomes, including successful intubation rate and postoperative outcomes, including POST, postoperative airway complications, epistaxis, dry throat, and hoarseness, were recorded within 24 h after surgery. A total of 140 patients completed follow-up and were included in the analysis. The incidence of moderate-to-severe sore throat (NRS ≥ 4) at 3 h postoperatively was significantly lower in the CCLH-Gel group than in the PL-Gel group (8/70 [11.4%] vs. 30/70 [42.9%]; absolute risk difference 31.4%, 95% CI 18.6%–44.3% relative risk [RR], 0.267; 95% CI 0.132–0.540, P < 0.0001;number needed to treat [NNT] ≈ 3.2). Furthermore, NRS scores for sore throat in the CCLH-Gel group were lower than those in the PL-Gel group at multiple time points (1, 2, 6, and 24 h postoperatively; all P < 0.001). Additionally, the overall incidence of post-extubation adverse events, including coughing, laryngospasm, and agitation, was significantly lower in the CCLH-Gel group compared to the PL-Gel group (10/70 [14.3%] vs. 24/70 [34.3%]; P < 0.05), with a particularly pronounced reduction in the incidence of coughing. CCLH-Gel applied to the endotracheal tube was associated with reduced incidence and severity of POST and fewer post-extubation airway adverse events after nasotracheal intubation, with no safety concerns observed. Multicenter trials are warranted to confirm its generalizability across diverse surgical populations. Clinical trial registration: The trial was registered on August 25, 2025, at Chinese Clinical Trial Registry (ChiCTR2500108092; https://www.chictr.org.cn ).