Cases of atypical pneumonia of unknown etiology were first reported in Wuhan, China in December 2019. Later that was confirmed to be caused by a new type of coronavirus. This novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), caused an epidemic in China and then rapidly spread around the world. As of April 20, 2020, 210 countries and territories have had patients infected with SARS-CoV-2 and the World Health Organization (WHO) declared it as a pandemic on March 11, 2020. It has affected health care resources, communities, economies, and countries, in a way that we have never seen before. More than 1 million have been infected and >50,000 died as of the date of this writing in the United States1, which is by all measures a very serious public health, health care crisis, and a human tragedy.
A massive surge in COVID-19 cases increased demands for medical resources such as hospital beds, personal protective equipment (PPE), SARS-CoV-2 testing kits, intensive care unit (ICU) beds, and ventilators, which led to a serious shortage of these resources in many hospitals worldwide. To avoid needs exceeding their capacity, many hospitals have activated measures to decrease demand and preserve supplies. For example, canceling elective surgeries, thus decreasing staff contact and exposure to the offending virus, and preserving PPE to make available for those caring for COVID-19 patients and keep hospital beds open and staff available for potential COVID-19 patients.
Emergent and urgent cases still needed to be done especially in the fields of head and neck surgeries, and bronchoscopy where airway emergencies are not uncommon, and procedures aimed at diagnosing and/or treating airway and lung malignancies are frequently encountered on daily basis. While care for emergent procedures continued, it was possible to delay some of the urgent/semiurgent procedures. Now that we have started seeing the “flattening the curve” phenomenon with a constant decrease in the number of SARS-CoV-2 diagnosed infections and related hospitalizations and ICU admissions, plans are underway to safely and gradually resume the care for time-sensitive (semiurgent, and semielective), and even elective procedures and surgeries. It is thought that these procedures present a high risk of potentially infectious exposure to the caring physicians and teams especially the anesthesiologists and plans, and protective measures should be used to minimize such risk.
In this article, we review the SARS-CoV-2 virus, its infectivity, pathogenesis, in the context of head and neck surgery, bronchoscopy, and dentistry. We will discuss these procedures’ characteristics and the mechanisms by which they pose an increased risk to health care providers (HCPs) especially the anesthesiologists, and recommendations for mitigating these risks based on the current state of knowledge and experience.
SARS-CoV-2 is a single-stranded RNA virus. The main route of transmission is thought to be droplets ejected when a patient coughs or sneezes, which are deposited on another person, or on objects/surfaces forming fomites (contaminated objects with infectious agents) and then transmit to any other person who touches these fomites. Moreover, SARS-CoV-2 is claimed to stay viable for hours and on some surfaces up to days2.
It is been also suggested that the coronavirus may be transmitted through aerosols. Aerosols are rather small particles that are emitted by coughing, sneezing, breathing vigorously, and even speaking loudly. Whereas the size of droplets is 1–5 mm and they reach a distance of up to 2 meters (≈6 feet), the size of aerosols is 1.0–5.0 μm and can remain hanging in the air and/or travel a distance of up to a hundred meters (≈300 feet)3. Whether SARS-CoV-2 is aerosol airborne or not is yet to be determined/confirmed, and needs more investigation4. However, the widespread viral infection, and published reports of its infectivity are difficult to explain based on a simple droplet transmission theory only. For example, some case reports have implied transmission by aerosols5,6. What complicates matters worse is that some reports indicate that SARS-CoV-2 may be transmitted from asymptomatic carriers6,7, and for symptomatic patients, they can be contagious even before they start having symptoms8. This pattern has some similarity to the infectivity pattern of the influenza virus; however, it contrasts with the SARS 2003 caused by the SARS-CoV-1 pattern when infectivity increases at 7–10 days post symptoms (this pattern increases the effectiveness of control measures)8. In addition, high viral loads exist in throat swabs soon after symptoms’ onset8. Not only that virus transmission starts before symptoms appear, but some actually believe that, that period might represent the peak of infectivity8. Given these reports CDC revised their recommendations and added the use of cloth face masks in public spaces especially when it is difficult to maintain “social distancing”9.
Aerosol-generating procedures (AGPs)
There are multiple procedures that could produce aerosols. According to a systematic review, these procedures include, but not limited to, intubation, extubation, bronchoscopy, endoscopy, otolaryngologic surgeries such as transnasal surgeries, and tracheostomies10. Oxygen therapy through a nasal cannula and some respiratory devices could also produce aerosols. Although some reports indicate that dispersion from noninvasive ventilation (NIV), for example, continuous positive airway pressure masks, and high flow nasal (cannula) oxygen (HFNO) reach only the very immediate surrounding area, and do not increase the risk of droplet infection, these devices could spread aerosols when the tight fit is not maintained in the case of continuous positive airway pressure, or never there to start with as in the HFNO11–13. Maximum exhaled air dispersion distance with oxygen therapy via nasal cannula is dependent on the oxygen flow rate, and reached a 100 cm (≈3 feet) at 5 L/min. Dispersion from NIV via a full-face mask in the bilevel positive pressure ventilation setting also reaches a rather long distance, and increasing inspiratory positive airway pressure leads to increasing dispersion distance14. These interventions could potentially put anesthesiologists, otolaryngologists, pulmonologists, and intensivists, and the rest of their team members at risk of contracting the infection.
Given the high infectivity of SARS-CoV-2, and the fact that some of these above interventions are potentially aerosolizing, such as using oxygen supplementation at a high rate through nasal cannulae, or utilizing NIV techniques, it is prudent that anesthesiologists would consider alternative techniques that would mitigate such aerosolization risk.
COVID-19 testing before surgeries and procedures
The Society for Ambulatory Anesthesia (SAMBA) issued a statement recommending that as feasible, all “patients are screened and tested as close to procedures as possible.” Timing depends on available logistics and resources. They state “We recommend testing 24–48 hours before planned procedures and no >72 hours as feasible.” They further recommended that “Symptomatic and SARS-CoV-2 virus-positive patients should be referred to appropriate resources and have elective procedures postponed” and “Once patients are tested they should be encouraged to self-isolate leading up to their procedures. Patients who have negative tests and continue to screen negative for COVID-19 like symptoms until the time of surgery can proceed with their planned elective surgery”15.
American Society of Anesthesiologists (ASA) and Anesthesia Patient Safety Foundation (APSF) also issued a joint statement on perioperative testing for the COVID-19 virus. While they recommend that all patients should be screened for symptoms before presenting to the hospital, and symptomatic patients should be referred for further evaluation, they do not require preoperative COVID-19 testing in asymptomatic patients when there is little to no local or regional presence of SARS-CoV-2. Patients from areas with more than “little presence of SARS-CoV-2 should undergo nucleic acid amplification testing before nonemergent surgery”16.
The rationale behind such recommendations is thought to be that in the case of the positive test, there is an increased risk to the patient him/herself (in terms of poor postoperative morbidity), and also the caring staff. In the case of negative test, due to possible asymptomatic carrier transmission, and the possibility of a false-negative test17, it is recommended that clinicians would still utilize aerosol (also referred to as respiratory) PPE (gloves, waterproof gown, eye protection, fit-tested N95 respirator or powered air-purifying respirator (PAPR) during aerosolizing procedures, and surgical masks and eye covering for nonaerosolizing procedures).
Head and neck surgery
A recent study showed that viral load was high on the nasal mucosa, saliva, and in the upper respiratory tract18, which put endoscopic nasal/sinus, and transnasal cranial surgery, laryngeal procedures, intubation, tracheostomy at higher risk of transmission of the virus. Thus many societies, and departments of otolaryngology-head and neck surgery and neurosurgery around the country and the world have developed guidelines and published manuscripts outlining their approach to address such concerns. For example, Stanford University developed guidelines for endoscopic transnasal skull base surgery19. Givi et al20, recently published a set of recommendations for head and neck surgery. Such recommendations stress the importance of COVID-19 preoperative testing and the use of respiratory PPE (gloves, waterproof gown, eye protection, fit-tested N95 respirator, or PAPR).
COVID-19 causes severe respiratory distress syndrome and 5%–10% of patients require ICU admission, and mechanical ventilation21. The indication for tracheostomy should be considered carefully considering what is currently known about the natural history of the disease. The American Academy of Otolaryngology-Head and Neck Surgery (AAOHNS) recommends that “Tracheotomy can be considered in patients with stable pulmonary status but should not take place sooner than 2–3 weeks from intubation and, preferably, with negative COVID-19 testing”22. If the decision is to proceed with the tracheostomy procedure in patients treated from COVID-19 disease. Considerations should be given to performing it at the bedside in the ICU to avoid unnecessary transport. All involved should be in full PPE. To minimize exposure to aerosolized secretions intraoperatively, the patient should be properly anesthetized and completely paralyzed to avoid coughing, mechanical ventilation should be halted just before entering into the trachea, and use of suction should be minimized23.
Bronchoscopy is also an AGP and presents a high risk for HCPs exposure to SARS-CoV-2. There are limited reports on indications and safety of bronchoscopy for patients with known or suspected COVID-19. The American Association for Bronchoscopy and Interventional Pulmonology (AABIP) and other pulmonology societies recently published guidelines24,25.
Note that, these guidelines consider that routine bronchoscopy for patients with known or suspected COVID-19 for the mere indication of diagnosing or confirming COVID-19 diagnosis is relatively contraindicated because of apparent risk of exposure to clinicians and uncertain benefit of the procedure. Possible indications as suggested by the AABIP include inconclusive noninvasive COVID-19 test, suspicion for an alternative diagnosis which would change clinical management.
When bronchoscopy is necessary for a patient who is a COVID-19 positive, these guidelines recommend to use a negative pressure procedure room for the procedure, limit personnel, use full PPE. Disposable bronchoscopes should be considered if available. Also, avoid atomizing patients’ airway and jet ventilation.
Other indications for bronchoscopy/interventional pulmonology including emergent or urgent interventions such as massive hemoptysis, severe airway stenosis, or significant endobronchial obstruction and diagnosing and staging lung cancer, and/or managing cancer-related complications could not be halted during the period of stopping elective procedures and were carried on with appropriate precautions. Now that the nation is recovering from the pandemic, and the number of infected patients is declining, resumption of semiurgent, and semielective, and eventually elective procedure is in order.
Thus, at this point, testing all patients presenting for bronchoscopy for SARS-CoV-2 is warranted. Again, COVID-19 positive patients should be directed to proper care, and bronchoscopy should be postponed if possible. As bronchoscopy is an AGP, management of patients with negative test should be carried out with proper PPE (gloves, waterproof gown, eye protection, fit-tested N95 respirator, or PAPR), minimizing staff and other necessary precautionary measures should be considered as above, given that many patients are asymptomatic and the possibility of false-negative test.
Furthermore, at the authors’ institution, many pulmonologists converted all their bronchoscopies typically done under moderate sedation in relatively sick patients, for example, those who are home oxygen dependent to be done under general anesthesia. That was for many reasons, they typically require many liters of oxygen supplementation and together with frequent coughing would increase the aerosolization of the virus during and following this already AGP, moreover doing these bronchoscopies under general anesthesia will avoid the nasal route for bronchoscopy commonly used when the procedure is done under procedural sedation, thus avoiding the nasopharynx altogether that is known for high virus load8. The above rationale is the same used by anesthesiologists avoiding the use of deep sedation or general anesthesia maintaining spontaneous ventilation without an endotracheal tube with significant nasal oxygen supplementation (commonly referred to by its related billing term, monitored anesthesia care or MAC).
On the other hand, Anesthesiologists are using the so-called rapid sequence induction for the most part to rapidly secure the airway to minimize aerosolization by avoiding mask ventilation, and complete paralysis to avoid cough during airway manipulation. When supraglottic airways are used for certain procedures like endobronchial ultrasound mediastinal staging, previously tolerated small leaks from not ideally seated supraglottic airway, are no longer tolerated, and immediately replaced with an endotracheal tube. Moreover, more anesthesiologists are paying more attention to using antitussive and postoperative nausea and vomiting prophylaxis interventions like administering 100 mcg of fentanyl for the former, and proper medication for the latter with induction to minimize the usual postprocedural coughing to decrease aerosolization in the recovery room26.
Many dental procedures are AGPs as well. The American Society of Dentist Anesthesiologists (ASDA) issued guidance during this COVID-19 pandemic27. As in the main operating room (OR), they prioritize dental emergencies and urgencies. Dental emergencies are potentially life-threatening cases such as severe dental bleeding, cellulitis, trauma to facial bones, and condition that pose a threat to airway patency. Dental urgencies include severe dental pain from pulpal inflammation, pericoronitis, postextraction alveolitis, abscess, fractured teeth with soft tissue trauma, etc. Some dental procedures can be done in ambulatory settings and this should be considered during the pandemic to reduce demand on hospital resources.
During procedures, dentists and anesthesiologists should wear proper PPE including N95 masks or PAPR, gowns, gloves, and eye protection. In other nonprocedural areas of the office, ASDA recommends that at least a surgical mask should be worn by all dental health care personnel and standard distancing precautions should be followed.
Anesthesiologist providing care for dental procedures should position themselves as far as practical away from the surgical field. If a nonintubated approach is considered but airway support is anticipated to maintain adequate ventilation during the procedure, this places the anesthesiologist at increased risk, then intubation should be considered. Supplemental oxygen by nasal cannula should be used at the lowest effective flow rate as it may increase virus aerosolization as well. Of note, high-speed drill was thought to be related to the spread of infection to HCPs but that notion has been later refuted28.
ASA and APSF provided recommendations regarding how to prepare and manage the airway of a patient with COVID-1929,30.
At this point of this pandemic, priority should be still given to emergent and urgent surgeries, followed by semiurgent, semielective, and then as the conditions improve, manifested by continuously decreasing the number of COVID positive cases in a given community, with decreased numbers of hospital COVID-related admissions, improved testing capabilities, and availability of proper PPE to protect clinicians. Then it would be appropriate to gradually increase the number of semielective and elective surgeries. With that, other measures to protect the public and HCP should be sought out and implemented. Use designated OR for COVID positive patients. Most experienced anesthesiologist and provider for a given procedure should be involved, and the number of staff assigned to the OR and exchange of the staff should be minimized29.
Some Anesthetic technique modifications have the potential to decrease aerosolization, for example, in vocal cord and management of subglottic stenosis surgeries performed by the otolaryngologists using suspension laryngoscopy where these were very successfully done with techniques such as jet ventilation and HFNO, switching to intubated, or intermittent apnea/intubation technique might be a bit safer to avoid jet ventilation and HFNO aerosolization. If intermittent apnea/intubation technique is not feasible, the authors believe that perhaps jet ventilation at least theoretically may have less aerosolizing potentials than HFNO, as it avoids the nasopharynx, and exhalation depends on the lung elastic recoil, versus the turbulent flow generated by the HFNO. The authors offer these recommendations in line with those offered by the AAOHNS to their members advising them “to limit the use of technology that theoretically may cause aerosolization”28.
Since intubation and extubation are AGP, guidelines, and recommendations have been issued31–33, recommending that anesthesiologists should wear appropriate PPE during these procedures. Proper donning and doffing is important to avoid contamination.
At the induction, an anesthesiologist should utilize 100% oxygen for adequate preoxygenation and consider rapid sequence induction as discussed above to avoid manual ventilation, which can produce aerosols. If the patient cannot tolerate apnea and manual ventilation is needed, use small tidal volume with the smallest positive pressure feasible.
The use video laryngoscope is recommended to increase the chance of successful intubation at the first attempt and allow for increasing the distance between the anesthesiologist’s face and the patient’s mouth compared with when the regular standard direct laryngoscopy blade. Place the used laryngoscopy into a designated tray to avoid contamination. A double gloves technique is recommended as well. Also, consider having other OR staff leave the room during intubation and extubation to decrease their risk of exposure to aerosols.
Some physicians have invented what is referred to as an “intubation box” or “aerosol box,” which is a box made of Plexiglas, designed to cover a patient’s head and to protect the anesthesia team from droplets during intubation34. However, while it sounds intriguing in theory, its efficacy or safety have not been demonstrated. Moreover, it is in the authors’ opinion, that perhaps the only benefit from such boxes is psychological relief to the team feeling that they are doing their best to avoid exposure to a potentially very harmful pathogen. However, we believe that other recommended interventions above during induction might be adequate, as well as utilizing techniques and strategies to minimize cough and strain during extubation that is commonly used during head and neck surgeries.
On the other hand, utilizing such boxes makes the intubation process cumbersome, more difficult at times, and may take a longer time, while the goal is to secure the airway as fast as possible. If difficulty in intubation is encountered, one can only imagine that this box will be tossed aside, and the procedure is redone, with a sense of urgency, that might be associated with forgoing proper protocol, or the team, may have relaxed their PPE protocol depending on the presumed protection from using the box. This concern has been addressed in a newly published article, which demonstrated longer intubation time, lower first-pass success, and breach of PPE with an aerosol box35. Also, it becomes a fomite, and disinfecting such a box after every use may pose some risks to those who are responsible for that process.
Awake fiberoptic intubation should be considered carefully and minimized or avoided if safely possible because coughing during the procedure as well as the mere use of the flexible intubating scope can cause aerosolization of the virus. When awake intubation is considered indicated for example in the ENT difficult airway, the authors recommend proceeding with appropriate PPE, and strategies to minimize aerosolization, like avoiding nebulizing or atomizing local anesthetics to tropicalize the airway, use nerve blocks, and/or viscus lidocaine gargle, or piled at the end of a tongue depressor wrapped up with gauze and applied to the anterior tonsillar pillar for a few minutes (the so-called lidocaine lollipop technique). Moreover, a lighter plain of sedation should be considered to avoid the need to use >2–3 L/MinO2 supplementation, and finally avoid the nasal route, if the flexible intubating scope is used for intubation, the oral route is preferred.
To minimize coughing at emergence, some clinicians have advocated deep extubation. It is the authors’ opinion that this is a risky strategy of unproven value. There is a potential for increased risk of aerosol generation if postextubation hypoxemia is encountered and mask ventilation, or many liters of oxygen supplementation is needed or emergent reintubation is needed when all other temporizing measures fail. Not to mention that anesthetized patient without a protected airway is at an increased risk for aspiration. A better approach is to follow techniques and strategies commonly used in head and neck surgeries. Adequate analgesia would decrease the chance of coughing, as opioid are known to be powerful antitussive. Covering a patient’s face with a clear plastic bag during extubation has been adopted by some and claimed to be helpful, and effective36 albeit not adequately tested either.
Head and neck surgeries, bronchoscopies, and dental procedures add to the risk of exposing anesthesiologists and other HCP, to the virus because of their virus aerosolizing potential. Appropriate PPE is recommended to be used for the care of these patients regardless of the COVID-19 testing status, as negative test result does not guarantee no infection due to the false-negative test rates, and the potential for exposure after the test was done and before surgery. All efforts should be done to minimize exposure to this virus during these procedures and in the OR. Concern, and care for the patients and teams caring for them are of equal and utmost importance.
Conflict of interest disclosures
Dr B.B.A. is the co-editor of 2 textbooks addressing many of the subtopics presented in this article: Anesthesia for Otolaryngologic Surgery and Clinical Airway Management: an Illustrated Case-Based Approach, published by Cambridge University Press. Dr C.D. declares that he has no financial conflict of interest with regard to the content of this report.
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