COVID-19 Pandemic: Negative-Pressure Tent During Atomization of Local Anesthetic for Awake Fiberoptic Intubation.

Abstract

To the Editor We read with great interest the editorial outlining the recommendation for endotracheal intubation of coronavirus disease 2019 (COVID-19) patients.1 Amid the COVID-19 pandemic, the safety of health care providers (HCPs) is paramount, especially for those performing aerosol-generating medical procedures (AGMPs). It was recommended that awake fiberoptic intubation (FOI) should be avoided as atomized local anesthetic during airway topicalization might aerosolize the virus, admitting the extent of aerosolization is likely multifactorial such as viral load, forceful coughing, duration of exposure, and ventilation system of the environment. Nonetheless, when confronted with an elective challenging airway, safe airway management takes precedent, even in the COVID-19 era. Herein, a novel technique to minimize aerosol dispersion during local anesthetic topicalization for awake FOI is described. This topicalization technique has been successfully performed clinically on a presumed COVID-19–positive patient (written informed consent obtained) with severe trismus of 2-finger breadths, undergoing resection of a large tonsillar tumor resulting in difficult ventilation and intubation. This prompted an elective awake FOI to be performed with this novel technique and was well tolerated by the patient without coughing or oxygen desaturation throughout the procedure. A negative-pressure “tent” to enclose the patient’s nose and mouth was assembled by attaching a clear, disposable, adult oxygen facemask (AirLife; Vyaire Medical Inc, Mettawa, IL) to the suction tubing (6 mm, 3.7 m; Cardinal Health, Waukegan, IL), which in turn was attached to the suction canister. For a non-rebreather mask, the reservoir bag could be removed with the opening sealed with tape. A “cross-shaped” slit was cut on the oxygen facemask to allow for the atomizer tubing to be inserted into the negative-pressure tent (Figure, panel A). Only a minimal number of HCPs considered necessary during the awake intubation should be present in the operating room with proper donning of airborne personal protective equipment (PPE). American Society of Anesthesia (ASA) monitoring was used, and 2 L/min of oxygen was applied via nasal cannula. The patient was lightly sedated with low-dose remifentanil, and the oropharynx was topicalized with lidocaine ointment before placement of the negative-pressure tent onto the patient’s face covering both the nose and the mouth, while oxygen was continued via the nasal cannula. We shaped the tip of the mucosal atomization device (MADgic; Teleflex Medical, Morrisville, NC) into a hockey stick and attached it to a 10-mL syringe filled with 2% lidocaine. We then inserted the atomizer through the cross-shaped slit of the facemask (Figure, panel B) into the patient’s mouth. We placed the atomizer device to the back of the oropharynx, and 10 mL of 2% lidocaine was slowly injected as the atomizer was advanced gently along the tongue base which took about 1 minute. The airway topicalization was completed, and we held the negative-pressure tent to the side of the patient’s face (or it could be repositioned to the patient’s forehead) with suction still attached. We then successfully performed an awake FOI.Figure.: The negative-pressure tent for airway topicalization. A, The assembly of the negative-pressure tent from a non-rebreather mask with the reservoir bag removed and the opening taped over with pink medical tape is shown. The cross-shaped slit is cut using scissors, and the suction tubing (with tip cut to fit) is attached to the port which is normally used for the oxygen tubing. B, The atomizer device can be inserted through the slit and manipulated freely during airway topicalization.To date, we are the first to describe an approach to minimize aerosol dispersal during airway topicalization for awake FOI amid COVID-19 pandemic. Given the high level of viral shedding in the upper respiratory tract2 and an increasing evidence of asymptomatic spread of COVID-19,3 caution is necessary during airway management. However, it should be emphasized that in situations where airway management poses a challenge, such as severe trismus or oropharyngeal/laryngeal tumor, patient safety might be jeopardized if awake FOI is avoided on the basis of minimizing harmful aerosol dispersal. The risk/benefit ratio should be carefully considered, while enhancing the safety of HCPs. Mucosal topicalization is feasible as described; this prevents close range airway exposure as encountered in glossopharyngeal nerve block or forceful coughing as experienced in recurrent laryngeal nerve block. Novel devices in the form of barrier enclosure have been suggested to contain droplets from a “forceful cough”4; however, this is not practical for awake FOI. Smoke evacuation devices or suction substitutes have been recommended to reduce aerosol transmission during desufflation of pneumoperitoneum in laparoscopic cases.5 Suction attached to a disposable oxygen face tent applied over a mannequin’s forehead has also been demonstrated to eliminate aerosolized vapor during simulated direct laryngoscopy.6 Applying these principles, a combination of barrier creation of the nose and mouth, as well as the negative pressure through suction, the aerosol generated from atomization of local anesthetic can potentially be contained, thereby minimizing the aerosol exposure to HCPs while providing optimal care for patients. One should note that this is an off-label use of commercial product amid COVID-19 pandemic which has not allowed time for well-investigated commercial products to be produced. Our technique of using negative-pressure tent is simple and cost-effective that can be readily applied onto the patient, serving to reduce aerosol dispersal during airway topicalization. When clinically indicated, awake FOI should not be dismissed, instead options should be explored to perform the procedure safely with a balanced risk/benefit ratio to both patients and HCPs. Vivian Ip, MBChB, FRCADepartment of Anesthesia and Pain MedicineUniversity of Alberta HospitalEdmonton, Alberta, Canada[email protected] Christopher Tham, RRTDepartment of Respiratory TherapyUniversity of Alberta HospitalEdmonton, Alberta, Canada