PPE for Airway Procedures
Otolaryngologists are commonly involved in AGPs requiring open or endoscopic airway instrumentation, including tracheostomy, direct laryngoscopy with interventions, and endotracheal intubation. A systematic review meant to assess the relative risk of transmission of SARS-CoV1 during a spectrum of AGPs found endotracheal intubation (odds ratio [OR]=6.6) and tracheostomy (OR=4.2) to be among the highest-risk procedures.15 On April 2, the American Academy of Otolaryngology (AAO) released an updated position statement recommending against elective tracheostomy within the first 2-3 weeks following intubation, in patients with high-pressure ventilatory requirements, and in patients without COVID-19 testing.16 Moreover, there is little existing evidence suggesting a definitive overall survival benefit associated with early tracheostomy among critically-ill patients.17 As such, the theoretical remaining benefits of early, elective tracheostomy (e.g. laryngotracheal morbidity) must be carefully weighed against the known risk of SARS-CoV2 transmission during tracheotomy procedures, when the option to bide time until viral clearance or ventilatory independence occurs. However, if patient circumstances (e.g. bulky head and neck tumor) necessitate a tracheostomy or elective tracheostomy is performed, appropriate PPE is strictly necessary.
PPE for tracheostomy procedures should abide by airborne-level precautions, which include an N95 mask with eye protection or PAPR, surgical cap, long-sleeved waterproof surgical gowns, gloves, and shoe/leg covers to prevent tracking. Some groups, cultivating their experience from treatment of either SARS-CoV1 or SARS-CoV2 patients, have advocated for enhanced PPE during high-risk, airway procedures, such as tracheostomy, including full face-shields or helmets with full face coverage and double gloves, or concomitant N95 and PAPR use.18,19 Other important considerations include 1) possibility of performing open tracheostomy in a negative-pressure room in the intensive care unit, to minimize unnecessary ventilatory circuit manipulation for patient transport; 2) complete muscular paralysis, when permitted (i.e. not awake tracheostomy), during the procedure to minimize coughing with an open airway; 3) minimization of electrocautery to mitigate the potential transmission of aerosolized virions through smoke20, and, 4) use of a closed tracheal suction system with a viral filter. While percutaneous tracheostomy can be considered as an alternative to intraoperative open tracheostomy, there may be similar, if not more significant, risk of aerosolization given the need for bronchoscopy and serial instrumentation of the airway for dilation.21 If awake tracheostomy cannot be avoided, additional unique considerations include adequate local anesthesia to prevent patient movement during the procedure, and a patient surgical facemask, with low-flow oxygen administration via nasal cannula, if necessary, to reduce large droplet transmission with coughing. Routine tracheostomy tube exchanges should be delayed in COVID-19 patients to limit airway manipulation; instead, simple cuff deflation should be considered to reduce mucosal irritation and facilitate phonation. If exchange is performed, standard airborne-level PPE (N95, eye protection or full faceshields, surgical gown, and gloves) should be donned by participating providers, including nurses and respiratory therapists.
Though specific guidelines have not been formulated for suspension microlaryngoscopy, the procedure exposes the distal airway with positive pressure ongoing (albeit with a seal created by the endotracheal tube cuff), and involves instrumentation of the respiratory mucosa. Given the CDC’s current characterization of intubation and bronchoscopy as “high-risk” procedures (i.e. either aerosolizing or associated with poor control of respiratory secretions), airborne precautions should be strongly considered for suspension microlaryngoscopy if surgery cannot be delayed (e.g. laryngeal cancer with marginal endoscopic resectability).22 Use of laser is common during microlaryngoscopic procedures; the risk of human papilloma virus (HPV) transmission has been studied in this setting. A study by Kunachack et al. found that no viable HPV virions could be cultured from CO2 laser plume.23 Another study by Ferenczy et al. found HPV DNA in the prefilter section of the smoke evacuator used to clear the surgical field of the laser plume; the inner, postfilter sections of the smoke evacuator, however were devoid of viral DNA.24While iatrogenic inoculation of the surgeon is not a widely reported phenomenon in the treatment of HPV related disease, it is unclear if empirical measures, including use of a smoke evacuator with a high-efficiency filter, or prior research concerning HPV would be applicable to SARS-CoV2. Lastly, jet ventilation should be avoided, if possible, given the procedure’s high applied pressure without an inflated cuff as a barrier to aerosolized virions. (Table 1)
Unless the otolaryngologist is required in the operating room during endotracheal intubation of COVID-positive or suspicious patients (e.g. if the risk of a surgical airway is high), only anesthesia providers should be present during intubation with appropriate PPE donned. A statement issued by the American Society of Anesthesiologists recommended standard airborne-level PPE (N95 respiratory with eye protection or facial protection covering the sides of the face versus PAPR, waterproof gown, and gloves) be worn by providers present during intubations for patients with confirmed or suspected COVID-19.25 Additional recommendations for the intubating provider include use of videolaryngoscopy to allow for greater distance between the provider and the patient and prompt inflation of the endotracheal tube cuff after passage through the vocal cords to create a seal before initiation of positive pressure ventilation.