To the Editor:—
Numerous techniques and maneuvers have been described to anesthetize the upper airway in preparation for awake tracheal intubation, notably the nerve block techniques to the superior laryngeal or the glossopharyngeal nerves as well as the topical application of a local anesthetic, in the form of a gel, spray, or inhaler.1The current report describes the efficacy of a lollipop containing 150 mg lidocaine HCl for providing upper airway analgesia for patients undergoing awake fiberoptic bronchoscope (FOB) tracheal intubation or direct laryngoscopy.
After extensive search through Medline and multiple other databases about the stability of lidocaine HCl salt, a lidocaine lollipop (LL) was developed in collaboration with the pharmacy at the American University of Beirut. Fifty grams of white sugar was heated until liquefied; an equal amount of maple golden syrup was slowly added. For each lollipop, 3 ml of this mixture was poured into a small cylindrical container, to which 150 mg lidocaine HCl salt was added and stirred. As the temperature cooled down and before the mixture solidified, a small plastic stick was plunged at one end for holding the LL. The ready-to-use LL was then labeled and stored in a refrigerator.
The protocol used was approved by the internal review board, and informed consent was obtained from all participants. Exclusion criteria consisted of any history of allergic reaction to local anesthetics, diabetes, or risk for aspiration of gastric contents. All participants had noninvasive serial blood pressure measurements, pulse oximetry, and continuous electrocardiographic monitoring. A total of 45 patients aged 25–78 yr, with American Society of Anesthesiologists physical status I–III, scheduled to undergo elective surgery and requiring general anesthesia and tracheal intubation were recruited. Premedication consisted of 5 mg oral diazepam and 0.2 mg intramuscular glycopyrrolate. All patients were given the LL on arrival to the holding area. The LL was easily consumed by all patients in 8–17 min. Its taste was described as good in more than 80% of patients and acceptable in the remaining participants. The onset of analgesia as depicted by sensation of tongue numbness was reported within 1–2 min.
After finishing the whole LL, and without any additional sedatives, patients were transferred to the operating room. Thirty of the 45 patients underwent awake FOB intubation. A single anesthesiologist introduced a No. 80 Berman intubating oral airway, advanced the FOB (3.8 mm Olympus LF2; Olympus Corporation, Lake Sweeney, NY) to the level of the vocal cords, and injected 2 ml lidocaine HCl, 2%, via the working channel to anesthetize the vocal cords and the trachea. The FOB was then advanced into the trachea, and the endotracheal tube was slid over the insertion cord of the FOB into the trachea.
In case of inability to perform FOB-guided intubation, 1 mg midazolam and 1 μg/kg fentanyl were administered intravenously, and then the FOB intubation was reattempted.
Tracheal intubation using the FOB was easily performed in 93.4% of patients with minimal or no discomfort, with no associated hemodynamic changes, and without the need for additional sedation. Furthermore, the incidence of gagging and discomfort that warranted additional sedation was observed in only 6.7% of patients, as compared with the reported 9.5% for topical analgesia, 10.5% for nerve block techniques,2or 8% for combined nerve block and topical anesthesia techniques.3
In the remaining 15 patients, an awake direct laryngoscopy in an attempt to visualize the vocal cords was performed. General anesthesia was then administered whether direct laryngoscopy and vocal cord visualization were successful or not. The incidence of gagging and failure of direct rigid laryngoscopy was significantly higher than that observed during FOB (46.7% vs. 6.7%, respectively). This may be due to the higher number of pressure receptors recruited during awake direct laryngoscopy than during the awake FOB-aided intubation.
In conclusion, the LL containing 150 mg lidocaine may provide a simple, noninvasive, hands-free, effective technique for awake FOB-aided tracheal intubation. The observed effectiveness of the LL technique could be explained by the continuous release of lidocaine from sucking the LL, in addition to swallowing of the saliva mixed with the local anesthetic. This allows for the homogenous spread of the local anesthetic, not only to the mucosa of the oropharynx, but also to the posterior third of the tongue, the area that contains the deep pressure receptors responsible for the gag reflex.1
*American University of Beirut Medical Center, Beirut, Lebanon. firstname.lastname@example.org