|Year : 2020 | Volume
| Issue : 5 | Page : 96-104
Anesthesia for oral surgeries during the COVID-19 pandemic
Sheila N Myatra1, Sushan Gupta1, Prathamesh S Pai2
1 Department of Anaesthesiology, Critical Care and Pain, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India
2 Department of Head and Neck Surgical Oncology, Tata Memorial Hospital, Homi Bhabha National Institute, Mumbai, Maharashtra, India
|Date of Submission||19-Jun-2020|
|Date of Acceptance||04-Jul-2020|
|Date of Web Publication||31-Jul-2020|
Prof. Sheila N Myatra
Department of Anaesthesiology, Critical Care and Pain, Tata Memorial Hospital, Dr. Ernest Borges Road, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
The severe acute respiratory syndrome corona virus 2(SARS-Cov2) virus replicates in the nasal cavity, nasopharynx, and the oropharynx. During oral surgery, the risk of viral transmission is high during instrumentation in these areas, while performing airway management procedures, the oral surgery itself, and related procedures. During the corona virus disease 2019 (COVID-19) pandemic, patients with an oral pathology usually present for emergency procedures. However, patients with oral cancer, being a semi-emergency, may also present for diagnostic and therapeutic procedures. When elective surgeries are resumed, these patients will come to the operating room. In asymptomatic patients, the false-negative rate can be as high as 30%. These patients are a source of infection to the healthcare workers and other patients. This mandates universal precautions to be taken for all patients presenting for surgery. Lesions along the airway, distorted anatomy secondary to cancer therapy, shared airway with the surgeon, surgical handling of the airway and the risk of bleeding, make airway management challenging in these patients, especially while wearing personal protective equipment. Airway management procedures, oral surgery, use of cautery, and other powered surgical instruments in the aero digestive tract, along with constant suctioning are a source of significant aerosol generation, further adding to the risk of viral transmission. Maintaining patient safety, while protecting the healthcare workers from getting infected during oral surgery is paramount. Meticulous advance planning and team preparation are essential. In this review, we discuss the challenges and recommendations for safe anesthesia practice for oral surgery during the COVID-19 pandemic, with special emphasis on risk mitigation.
Keywords: Anesthesia for oral surgeries, COVID-19 pandemic, oral surgeries in COVID-19 patients, SARS coronavirus 2
|How to cite this article:|
Myatra SN, Gupta S, Pai PS. Anesthesia for oral surgeries during the COVID-19 pandemic. J Anaesthesiol Clin Pharmacol 2020;36, Suppl S1:96-104
|How to cite this URL:|
Myatra SN, Gupta S, Pai PS. Anesthesia for oral surgeries during the COVID-19 pandemic. J Anaesthesiol Clin Pharmacol [serial online] 2020 [cited 2020 Sep 27];36, Suppl S1:96-104. Available from: http://www.joacp.org/text.asp?2020/36/5/96/291189
| Introduction|| |
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the associated coronavirus disease 2019 (COVID-19) has emerged as a global pandemic, resulting in unprecedented pressures on the healthcare systems globally. Elderly individuals and those with serious underlying medical conditions might be at higher risk for severe illness from COVID-19. Cancer is in itself a high risk for severe illness with COVID -19, with a study in 928 cancer patients showing significantly higher 30-day all-cause mortality in those with general risk factors and moderate or poor Eastern Cooperative Oncology Group (ECOG) performance status.
SARS-CoV-2 virus replicates in the nasal cavity, nasopharynx, and the oropharynx. The maximum viral load is present in the respiratory tract and procedures involving the respiratory tract cause major aerosolization of the virus. Thus, the risk of viral transmission might be higher with instrumentation in these areas during airway procedures (tracheal intubation, bronchoscopy, tracheostomy) and while performing oral surgery. Most patients presenting to the operating room (OR) during the pandemic are for an emergency procedure or a tracheostomy. When elective surgeries are resumed, patients with oral pathologies will present to the OR. These patients may be asymptomatic or prodromal. In asymptomatic patients, the false-negative rate can be as high as 30%. These patients are a significant source of infection to the healthcare workers and other patients. This mandates universal precautions for all patients presenting to the OR.
All this notwithstanding, cancer is a semi-emergency and patients will present for diagnostic, therapeutic, or emergency procedures. A recent study from our center, Tata Memorial Hospital, showed favorable outcomes in 494 patients who underwent major elective cancer surgeries, thereby supporting the continuation of elective major cancer surgery during the COVID-19 pandemic. There are recent safe practice recommendations for head and neck surgical oncology practice in the setting of acute severe resource constraints during the COVID-19 pandemic by the Head and Neck Cancer International Group (HNCIG), a collaboration of 20 national clinical trial groups for head and neck cancer in which Tata Memorial Hospital has contributed.
Airway management in a patient presenting for elective or emergent oral procedures poses a unique challenge to the anesthesiologist. Lesions along the airway, distorted anatomy secondary to cancer therapy, shared airway with the surgeon, surgical handling of the airway and the risk of bleeding, make airway management challenging in these patients, especially while wearing personal protective equipment (PPE). Airway procedures, oral surgery, use of cautery, and other powered surgical instruments in the aerodigestive tract, along with constant suctioning are a source of significant aerosol generation, further adding to the risk of viral transmission.
In this review, we discuss the challenges and recommendations for safe anesthesia practice during oral surgery including tonsillectomy, intraoral wide excisions, and transoral laser resections during the COVID-19 pandemic, with special emphasis on risk mitigation.
| How Does the Virus Spread in the Operating Room?|| |
The SARS-CoV-2 is a single-stranded enveloped RNA virus with a diameter of 100–160nm. This virus can be transmitted in an OR by one of these methods:
- Direct spread via inhalation of respiratory droplets (size >5-10um) when the patient speaks, coughs or sneezes
- Generation of aerosol (airborne droplet) particles: Airway instrumentation can cause aerosolization of the respiratory droplets from the patient, which tends to remain in the air for about 2–3 hours or longer
- Spread via contact of an infected innominate object: The virus can enter via touching of face, nose, or eye. The infectious bigger droplets tend to fall quickly over the surface and have a shorter half-life.
A surgical mask worn by the patient can significantly reduce this viral transmission via droplets. The N-95 mask is effective against aerosols and significantly better than surgical masks in case of a droplet mode of infection.
| What Is an Aerosol Generating Procedure (AGP)?|| |
The Centre for Disease Control (CDC) defines an aerosol generating procedure (AGP) as one that generates a higher concentration of fine airborne droplets called aerosols. Procedures involving the respiratory tract are associated with significant aerosolization. 4] While larger droplets tend to quickly fall on the ground, smaller droplets (<5um) can float in the air for several hours and can also remain active on surfaces for a longer time.
The AGPs commonly performed by anesthesiologists, include, noninvasive ventilation (NIV), high flow nasal cannula oxygen (HFNO), mask ventilation, nebulization, bronchoscopy, tracheal intubation, extubation, and tracheostomy. These are commonly performed procedures, especially during the management of a difficult airway, as may be the case in a patient presenting for oral surgery.
Theoretically, these aerosols can pass through pores of a surgical mask, thus such procedures require the use of the N-95 mask protection or higher. The risk of infection from an AGP is even more with prolonged exposure, poor infection control compliance, such as poor hand-washing, inadequate spacing, and the ineffective use of PPE.
| Aerosol Generation during Surgery|| |
Aerosols are generated with the use of powered surgical devices such as the cautery, drill, micro-debriders, saw, and ultrasonic devices.,, Use of these devices in the upper airway during surgical procedures poses a significant threat to the spread of the virus. When the laser is used for excision of oral lesions, the plumes generated have been shown to contain viable viral load, which can infect the healthcare personnel in the OR. Covering the microscope and the patients with a transparent plastic drape may help contain the aerosols generated, which can be sucked out using the laser plume extractor.
| Personal Protective Equipment (PPE)|| |
The PPE acts as a barrier device in protecting the OR personnel and preventing them from becoming a carrier of viral droplets generated during the surgery. It also prevents cross-contamination from infected patients. The PPE includes a fluid impervious coverall/gown, a cap, goggles, a fit-tested N-95 mask, a double layer of gloves, a head hood or a full-face shield and long shoe covers., If available, a full face shield respirators or powered air purifying respirators (PAPRs) may be used instead of the N-95 masks. A surgical mask reduces this viral transmission via droplets, while the N-95 mask is also effective against aerosols. The WHO recommends the use of airborne, droplet, and contact precaution when aerosol-generating procedures are performed.
The amount of risk depends on the total viral load in respiratory secretions and the duration of exposure. Hence, despite the use of PPE, healthcare workers should limit the time period in close proximity of an infected patient. It is essential to have a separate designated area for performing supervised donning and doffing to minimize self-contamination and have minimal contamination of the OR and surrounding areas.
| Operating Room Preparation|| |
The ORs are routinely positive pressure areas (5–10 cm H2O). However, a negative pressure OR is preferred, as it prevents the spread of the virus outside the room. Changing from an existing positive to a negative pressure system if feasible should be done in advance after consultation with engineers. Increasing the air exchanges in the OR should be considered. Each “air exchange” removes approximately 63% of the potentially virus bearing aerosols in the air. Thus, after five air exchanges, <1% of the original aerosol load is left in the room. Scavenging of anesthetic and expired gases from the anesthesia machine via an appropriate exhaust is required. The OR door must be kept closed at all times. The information and understanding of the number of OR air exchanges will help plan the safe time interval required before entering the OR for the next surgery.
Additional requirements in the OR, specifically for use during the pandemic include two heat and moisture exchanging filters (HMEF) to prevent contamination of the breathing circuit and the anesthesia machine, a videolaryngoscope (VL), closed tracheal suction system, barrier devices like a transparent sheet or a customized intubation box (optional) and disinfectant solutions like 1% sodium hypochlorite or as per the institutional policy.
A standby airway cart bearing additional airway equipment that may be required, such as alternate size end tracheal tube (ETT), masks, oral/nasal airways, rescue airway equipment etc. should be available just outside the OR to avoid contamination.
| Team Preparation|| |
Avoid having healthcare workers with comorbidities, immunocompromised status, pregnancy, and advanced age as part of the OR Team. Advance teaching and training of all OR team personnel in the proper performance of hand sanitization, donning, and doffing of PPE is essential for preventing cross-contamination. Prior simulation-based training in the OR wearing full PPE with the use of patient barrier devices (if planned) is essential to prepare for airway management using unfamiliar and modified techniques.
Barrier devices may be used during aerosol-generating procedures like tracheal intubation, mask ventilation, extubation, bronchoscopy, etc. Though widely used, there is no evidence regarding the efficacy of these barrier devices in reducing aerosol spread. A recent study showed that the aerosol boxes may increase intubation time and therefore expose patients to the risk of hypoxia. In addition, they may cause damage to conventional PPE, placing the airway operator at risk of infection.
There may be significant cognitive dysfunction while performing airway management using PPE, which may affect performance, hence advanced practice is essential. Communication after donning PPE is challenging, especially in the use of critical language during an airway emergency, which can occur while dealing with patients with a difficult airway for oral surgery. Advance training in the use of sign language may be useful to overcome this.
| Factors for Prioritization of Head and Neck Cancer Patients for Surgery|| |
The HNCIG has developed consensus practice recommendations for head and neck surgical oncology that can be applied globally in the setting of severely constrained resources during this pandemic. They identified the five most important factors to be considered for prioritization of surgery to be based on. likelihood of tumor progression due to delay in surgery. COVID-19 status of the patient, (risk to the patient, other patients, and staff). disease prognosis. availability of infrastructure to operate on patients with COVID-19 and the availability and effectiveness of alternative treatments.
| Patient Assessment and Preparation|| |
Patients with oral cancer are usually elderly with associated comorbidities. Advanced age and comorbidities are associated with adverse outcomes in COVID-19 patients. Most of these patients may also be malnourished, anemic secondary to dysphagia, chronic inflammation or chemotherapy, adding to the increased risk of postoperative morbidity. In addition, tobacco chewing and smoking may further cause cardiorespiratory compromise.
Previous cancer therapies
History of previous cancer therapies must be noted in patients with oral cancer. Prior surgery or radiation to the head and neck region can make airway management in these patients difficult. This may be secondary to distorted anatomy, trismus, post-radiation edema, and fibrosis. Such patients may require awake tracheal intubation (ATI), which is associated with significant aerosol generation. Prior chemotherapy can cause end-organ damage, thus cardiac, renal, and coagulation systems should be assessed.
A careful history of progressive dysphagia, hoarseness of voice, breathlessness might give an important clue regarding airway compromise. In patients with oral cancer, a primary tumor along the airway, prior radiation or surgical therapy, poor submental compliance, trismus, ankyloglossia, and poor dentition all contribute towards an anticipated difficult airway. Airway imaging studies like CT scan, X-ray, previous direct or indirect laryngoscopy, help in assessing the extent of the tumor, and the expected difficulty in securing the airway. Based on the airway assessment, a plan for securing the airway (awake or asleep) should be made by the anesthesiologist with the surgical team.
PPE should be worn while examining the patient. Awake patients should be made to wear a surgical face mask and directly transferred to the OR bypassing the preoperative holding area. Recent studies have shown that povidone-iodine (0.23-1%) gargles and nasal drops administered prior to transfer to the OR significantly reduces viral load in the oro and nasopharynx. Povidone-iodine has multimodal activity against pathogens. It targets the structure needed for viral replication and survival.
| Tracheal Intubation Procedure|| |
It is important to have all essential items readily available to the airway operator prior to administering general anesthesia. To increase the chance of first-pass success during airway management, the most experienced airway operator among the team members should perform TI. Minimize the airway management team (preferably two persons). Only essential staff should be present in the OR at the time of tracheal intubation. All team members should be briefed about specific patient concerns, their specific role, airway management strategy, and airway rescue plan. The method of communication after donning PPE should be discussed.
- The patients should be wearing a surgical mask and covered with a transparent plastic sheet or an intubation box (if used) while on the OR table
- An HMEF is attached between the breathing circuit and the mask and another one is attached between the expiratory limb of the breathing circuit and the anesthesia machine. The side stream capnography tubing is attached to the machine end of the HMEF
- Position the patient appropriately. Minimize the time between removal of the patient's mask and the application of the face mask
- Preoxygenation with 100% oxygen for 3–5 minutes using a tight-fitting face mask and a two-hand technique with tidal volume breathing using a closed circuit is recommended. Preoxygenation with HFNO and NIV should be avoided
- Continuous waveform capnography should preferably be used during pre-oxygenation. A triangular rather than a square end-tidal carbon dioxide (EtCO2) trace or a low numerical EtCO2 value during preoxygenation, may indicate a leak around the face mask and should prompt interventions to improve the seal.
Induction of general anesthesia
- Rapid sequence induction (RSI) is the preferred method to avoid mask ventilation and facilitate faster tracheal intubation,,
- Appropriate doses of rapidly acting neuromuscular blocking drugs like rocuronium or suxamethonium should be used to achieve complete muscle relaxation
- Cricoid pressure should be avoided if the patient is adequately fasted. Use of cricoid pressure makes the assistant lean closer to the patient's airway, thereby increasing the risk of exposure to aerosols
- Avoid mask ventilation to prevent aerosol generation, unless the oxygen saturation (SpO2) goes below 95%. Mask ventilation if required should be done with a tight mask fit using a two-hand technique to prevent leaks around the face mask. Apneic oxygenation with HFNO should be avoided.
- VL assisted tracheal intubation is recommended to keep the face away from the oral cavity and increase the chance of first pass intubation success. It is preferable to preload the ETT with a stylet or use a bougie as appropriate
- After tracheal intubation, the ETT cuff should be inflated and the HMEF connected directly to the ETT. Ensure that there is no leak around the ETT cuff
- Mechanical ventilation should be initiated only after the ETT cuff is inflated. Confirm ETT placement in the trachea using waveform capnography. The use of a stethoscope is not feasible while wearing PPE.
Disposal and decontamination of contaminated equipment
Single-use items should be immediately discarded in the appropriate disposal bags and reusable items dropped into the container with disinfectant solution, without touching them elsewhere.
| Unanticipated Difficult Airway Management|| |
In case an unanticipated difficult airway is encountered during the first attempt at tracheal intubation, the guidelines for unanticipated difficult airway in adults during the COVID-19 pandemic may be followed to ensure patient safety while minimizing the risk of cross-infection.,,
When faced with an unanticipated difficult airway, avoid using HFNO and face mask ventilation with a leak, as they may lead to aerosol generation. A two-person two-hand technique should be preferred for mask ventilation. Two further attempts at tracheal intubation are recommended only if the SpO2 is ≥95% with intermittent mask ventilation performed only if the SpO2 is <95%. Further attempts at tracheal intubation should be done using a VL.
The use of a second-generation supraglottic airway (SGA) is recommended in case of a failed tracheal intubation. Awakening the patients should be preferred after established ventilation with an SGA. Avoid tracheal intubation through the SGA and performing a tracheostomy, as they are high AGPs. In the event of a complete ventilation failure, it is recommended to proceed with a surgical cricothyroidotomy. Avoid a needle cricothyroidotomy with the use of jet ventilation as this may increase the chances of aerosol spread.
| Precautions during General Anesthesia to Prevent Viral Spread|| |
- Maintain an adequate depth of anesthesia and neuromuscular blockade throughout the surgical procedure to avoid any bucking or coughing
- Avoid unnecessary disconnection of the ETT and the breathing circuit during mechanical ventilation
- If a circuit disconnection is required, put the anesthesia machine on a standby mode. Keep the HMEF connected to the ETT during disconnection. However, if an HMEF change is required or a tracheal aspirate needs to be collected, clamping the ETT transiently may be considered
- If a self-inflating bag needs to be used for manual ventilation, attach it to the machine end of the HMEF
- Tracheal suction should be done using a closed suction system at all times.
| Awake Tracheal Intubation|| |
An awake tracheal intubation (ATI) is associated with significant aerosol generation and thus should be avoided if possible. However, it might be necessary in case of an anticipated difficult airway, where induction of anesthesia before securing the airway might be considered unsafe for the patient. Anesthetizing the airway using local anesthetic techniques is challenging. There is a potential risk of aerosol generation with all the techniques. Thus, these should be performed with the use of PPE, after weighing the benefits and the risks of the local anesthetic technique. Nebulization is best avoided as it is considered as an AGP. It is important to keep in mind that even after anesthetizing the airway, the patient may still cough during the procedure resulting in a potential aerosol generation. In addition, the use of a flexible bronchoscope may itself take time, increasing the risk of viral transmission. If feasible, awake VL aided tracheal intubation (TI) should be preferred over TI using a flexible bronchoscope, as it is associated with shorter TI time.
Proper planning, preparation, and execution of the procedure is required to ensure patient and operator safety. Modification of techniques to reduce aerosol generation and spread is required. The goal should be to minimize TI time, reduce aerosol generation, and prevent aerosol transmission. Adequate sedation and other measures might be necessary to suppress the cough reflex and allay the patient's anxiety. Dexmedetomidine or remifentanil infusion are preferred for their favorable pharmacokinetics. Adequate counseling and optimal level of sedation increases the success rate and decreases the procedural time.
The postoperative airway of patients undergoing oral surgery can be managed using a tracheostomy or a delayed extubation strategy. Delayed extubation usually involves keeping the patient intubated overnight and extubating the patient in the morning. This decision is usually based on the extent of surgical resection and the reduction in airway caliber due to a bulky flap.
| Elective or Emergency Tracheostomy|| |
Tracheostomy is an AGP performed either as an emergency or an elective procedure in an intubated patient. It is preferable to perform a tracheostomy in the OR. The OR personnel should be reduced to minimal during the procedure. Different size tracheostomy tubes should be readily available. Only cuffed, nonfenestrated tracheostomy tubes should be used. An experienced surgeon should perform this procedure to reduce the time required.
The patient should be given 100% oxygen through ETT to increase the safe apnea time during tracheostomy. The depth of anesthesia should be adequate to prevent patients from coughing or bucking. As the surgeon dissects the anterior wall of the trachea, and the trachea is opened, mechanical ventilation should be stopped. The anesthesiologist should deflate the cuff of the ETT and withdraw it partially to allow the surgeon to place the tracheostomy tube into the trachea. The tracheostomy tube should be pushed distally and cuff hyper-inflated to avoid any air leak. The anesthesia circuit with the viral filter should be attached to the tracheostomy tube. Mechanical ventilation should commence once after a closed system is established. The tracheal position of the tracheostomy tube should be confirmed by the presence of capnography tracing.
| Tracheal Extubation|| |
Tracheal extubation is a higher AGP than tracheal intubation and should be done with all precautions as used during tracheal intubation. A deeper plane of anesthesia should be preferred during extubation if airway compromise is not a risk. Pharmacological methods may be used to avoid coughing and agitation. Tracheal suction should be performed only if required, using a closed suction system. Alternately, the anesthesiologist can pass the face mask over the ETT to cover the mouth during tracheal extubation to reduce the risk of aerosol spread in case of coughing. Airway manipulation and the use of airway exchange catheters should be avoided.
Following major oral surgery, most patients are kept intubated overnight to maintain airway patency while allowing time for the airway edema to settle. Healthcare workers should wear the recommended PPE with an N-95 mask while managing these patients in the recovery room/ICU. Patients should be adequately sedated overnight to avoid anxiety and coughing while the tube is in situ. A closed tracheal suction should be used and suction performed only if required. Nebulization being an AGP should be avoided and metered dose inhalers should be used instead. The ETT cuff should not be deflated for tracheal extubation until the staff are adequately protected. Tracheal extubation should be carried out using the same precautions as in the OR.
| Management of a Patient With a Tracheostomy|| |
It is preferable to have a separate area in the ward dedicated to patients with a tracheostomy. In a tracheotomized patient, extreme care should be exercised during patient transfer in and out of the OR to prevent viral transmission. Gauze pieces or a bib may be placed above the tracheostomy tube to limit the release of respiratory droplets to the surrounding, especially during coughing. If a tracheostomy tube change is required, full PPE should be worn. The tracheostomy tube cuff should not be deflated until the surrounding healthcare staff are adequately protected. A cuffed tracheostomy tube should be changed to an uncuffed tracheostomy tube only when the patient is confirmed to be COVID-19 negative.
| Care during Routine Oral Surgery|| |
Tonsillectomy is the most commonly performed oral surgery in the pediatric age group. The tonsils can harbor a high viral load, making tonsillectomy a high-risk procedure for cross-infection. The concerns for administering general anesthesia are the pediatric age group, upper respiratory tract infection, bleeding tendency, and the risk of a postoperative bleed. Children with COVID-19 may have a reactive airway, adding to the risk of perioperative airway compromise. Agents with lesser airway irritation should be preferred for the induction of anesthesia.
The main concern while managing a patient for tonsillectomy is to ensure minimal disconnection of the anesthesia circuit and avoid any air leak. A south-pole tube may be preferred with laryngeal packing. It provides an advantage for easy ventilation when the Boyle–Davis gag is used. Closed suction should be preferred, even for clot extraction. Tracheal extubation in a deeper plane of anesthesia in a lateral position may be considered. In the case of rebleeding, large-bore intravenous access for rapid resuscitation, smaller size ETT, lateral position, and rapid tracheal intubation are necessary. Similar precautions should be followed while resecuring the airway as mentioned earlier.
The Do's and Don'ts for perioperative management of patients for oral surgery during the COVID-19 pandemic are summarized in [Table 1].
|Table 1: Do's and don'ts for perioperative management of patients for oral surgery during the COVID-19 pandemic|
Click here to view
| Conclusion|| |
The SARS-CoV-2 pandemic and the COVID-19 disease has resulted in unprecedented pressures on the healthcare systems globally. Maintaining patient safety, while protecting the healthcare workers from getting infected during oral surgery is paramount. Meticulous preparation of the OR and the team in advance is essential. Preparing a team of surgeons, anesthesiologists, nurses, and other healthcare personnel who understand and implement measures to mitigate the spread of the virus in the perioperative period, especially during tracheal intubation, oral surgery, extubation, and tracheostomy may help achieve this goal.
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Conflicts of interest
There are no conflicts of interest.
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