For patients, intubation is an uncomfortable procedure that is intolerable without pharmacological support. Patients also typically experience discomfort after extubation, with postoperative sore throat being among the most commonly reported complaints following general anesthesia with endotracheal intubation, having an incidence ranging from 14% to 100% depending on patient characteristics, tube size, cuff design, and assessment methodology. To attenuate airway mucosal injury, clinicians employ pharmacological strategies like topical lidocaine, which is one of the most widely used interventions. Topical lidocaine can be administered either as a spray applied to the endotracheal tube (ETT) cuff and/or surrounding structures or as a gel or jelly lubricant applied to the tube’s distal end prior to intubation.
Early research comparing different forms of topical anesthesia for intubation studied 94 surgical patients randomized to receive laryngeal lignocaine spray, lignocaine jelly applied to the ETT cuff, the combination of both, or no lubrication. Counterintuitively, the combination group exhibited the highest rate of postoperative airway side effects at 95%, compared to 62% in the unlubricated control group. Jelly alone produced side effects in 85% of patients, and spray alone in 68%. These findings challenged early assumptions that any form of topical anesthesia would be uniformly protective and raised the possibility that certain formulations or their additives could independently irritate the tracheal mucosa.
A double-blind randomized trial of 204 patients undergoing cataract surgery under general anesthesia compared six distinct lidocaine application methods. Patients receiving 2% lidocaine jelly on the ETT tip demonstrated among the highest frequencies of both postoperative cough and sore throat—performing worse than the saline control group in cough frequency and exhibiting the greatest sore throat burden at one hour post-extubation. In contrast, intracuff lidocaine and intravenous lidocaine administered at the conclusion of surgery provided the most effective protection against both outcomes.
Another study compared lidocaine formulations and other medications, randomizing 372 patients to receive either benzydamine hydrochloride spray, 10% lidocaine spray, 2% lidocaine spray, or normal saline applied to the ETT cuff prior to intubation. At six hours post-extubation, the 10% lidocaine group exhibited a rate of postoperative sore throat of 53.7%, significantly exceeding not only the benzydamine group (17.0%) but also the 2% lidocaine (37.0%) and normal saline (40.8%) groups. The 10% spray applied to the ETT tip produced intermediate results, performing better than jelly but considerably worse than intracuff or systemic routes. These findings suggest that the route and pharmacokinetic profile of delivery are critical determinants of efficacy.
The severity of symptoms at one, six, and twelve hours was also significantly elevated in the 10% lidocaine group compared to both lower-concentration and saline controls. The authors attributed this paradoxical worsening to the excipients present in the 10% lidocaine formulation—specifically ethanol, polyethylene glycol 400, menthol, saccharin, and macrogol—which can independently irritate tracheal mucosa.
This mechanistic hypothesis received additional support from Taşkın et al., whose 2025 randomized controlled trial demonstrated a markedly different outcome when 10% lidocaine was delivered via the Trachospray device, a soft mist inhaler that distributes the agent evenly across the vocal cords, using a pure, additive-free lidocaine hydrochloride formulation containing only sodium chloride as an excipient. In 100 patients undergoing laparoscopic cholecystectomy, the Trachospray group exhibited significantly lower postoperative sore throat severity and incidence at all measured time points (2, 6, 12, and 24 hours).
Additionally, changes in heart rate and both systolic and diastolic blood pressure were significantly attenuated at one minute following intubation, suggesting a meaningful hemodynamic benefit. These results imply that the poor performance of 10% lidocaine spray in prior studies may reflect formulation-specific irritant effects rather than any intrinsic pharmacological limitation of the drug itself.
A 2019 systematic review and meta-analysis included 14 randomized controlled trials encompassing 2,146 patients. Across all formulations and delivery routes, lidocaine lubricants applied to the ETT tip demonstrated no statistically significant benefit over controls for postoperative sore throat at one or twenty-four hours, moderate-to-severe symptoms, postoperative cough, or postoperative hoarseness.
The authors proposed that the pharmacological pain-suppressing effect of lidocaine may be counteracted by the mucosal irritant properties of preservatives and additives commonly included in commercially available preparations. They also noted in vitro evidence that lidocaine concentrations of 5% or greater can induce apoptosis in human oral mucosal fibroblasts. In light of the potential cytotoxic effects of lidocaine jelly on laryngeal mucosa, the authors explicitly recommended against the routine use of lidocaine lubricants for orotracheal intubation.
Taken together, the available evidence suggests that the clinical utility of lidocaine spray vs. gel for intubation is highly formulation- and route-dependent. Lidocaine gel applied to the ETT cuff or tip does not reduce postoperative symptoms and may worsen discomfort through mucosal irritation. High-concentration lidocaine spray (10%) in conventional formulations similarly exacerbates sore throat, likely owing to excipient effects. Intracuff lidocaine remains the most evidence-supported topical route among the formulations studied. Newer delivery systems that employ additive-free lidocaine via soft mist devices represent a potentially promising avenue, though further investigation in larger and more heterogeneous surgical populations is warranted before firm clinical recommendations can be made.
References
- Klemola, U. M., Saarnivaara, L. & Yrjölä, H. Post-operative sore throat: effect of lignocaine jelly and spray with endotracheal intubation. Eur. J. Anaesthesiol. 5, 391–399 (1988). https://pubmed.ncbi.nlm.nih.gov/3240760/
- Soltani, H. A. & Aghadavoudi, O. The effect of different lidocaine application methods on postoperative cough and sore throat. J. Clin. Anesth. 14, 15–18 (2002). https://doi.org/10.1016/S0952-8180(01)00344-0
- Hung, N. K. et al. Effect on postoperative sore throat of spraying the endotracheal tube cuff with benzydamine hydrochloride, 10% lidocaine, and 2% lidocaine. Anesth. Analg. 111, 882–886 (2010). https://doi.org/10.1213/ANE.0b013e3181d4854e
- Taşkın, K. et al. Efficacy of lidocaine via trachospray in postoperative sore throat and hemodynamic response to intubation: a randomized controlled trial. BMC Anesthesiol. 25, 133 (2025). https://doi.org/10.1186/s12871-025-03004-2
- Liao, A. H. W. et al. Lidocaine lubricants for intubation-related complications: a systematic review and meta-analysis. Can. J. Anesth. 66, 1221–1239 (2019). https://doi.org/10.1007/s12630-019-01408-6