Reprint: Airway Management and Related Procedures in Critically Ill COVID-19 Patients: Position Statement of the Indian Society of Critical Care Medicine

Environment

All patients with COVID-19 disease should be treated in a negative-pressure room. Care of patients in positive-pressure rooms should be avoided. During the pandemic, the negative-pressure rooms might become scarce, and these rooms can be used for AGPs, especially for high-risk procedures. Certain hospitals might have dedicated rooms for endotracheal intubation, but in view of risks involved in transporting hypoxic and potentially infective patients, this should be avoided.

The time needed for dissipation of aerosol also depends on the number of air exchanges in the room, and it should be maintained above 12 exchanges per hour. With this, the aerosol is cleared with 99% efficiency in %3C;30 minutes.¹⁰ In the real world, negative-pressure rooms are finite and therefore not many will be available, as the number of patients increase and therefore airway procedures may need to be performed in compromised environment, as the resources become depleted. This may lead to increased risk of transmission of infection to HCWs.

Personal Protective Equipment (PPE)

If possible, minimum number of HCWs should be present during AGPs. All HCWs present near the patient should wear PPEs in the form of head cover or hood, eye protection in the wrap around goggles with shield, N95 respirator or higher level respirators (FFP2 standard/powered air-purifying respirator (PAPR), neck protection, gowns that meet a minimum standards of Association for Advancement of Medical Instrumentation level 2, shoe covers, and minimum of double pair of gloves—overlapping the gown sleeve to protect the wrists while handling the airway.¹¹ Use of double pairs of gloves has been shown to reduce the risk of transmission of infectious particles.¹¹ An additional pair of gloves will also prevent unnecessary soiling of the PPE and thereby wastage of scarce resources.

Powered air-purifying respirators have higher filtration efficiency when compared to N95 respirators and should be used whenever available.¹² The PAPRs also do not require prior fit testing and are more comfortable, especially when performing high-risk procedures, as additional shield is not required. When PAPRs are used, special care should be taken while doffing and donning, and proper decontamination should be ensured to reduce the risks associated with reuse. In resource-limited settings where appropriate gowns are not available, it is prudent to use double-layered clothing to reduce the risk of transmission.

Airway Management Team of HCWs

High-risk AGPs such as TI should be performed by the most experienced clinician in the team. This would minimize the number of attempts at intubation and improve the first-pass success rate. Airway team should be formed in each ICU, and the team should comprise of at least one intensivist or anesthesiologist with expertise in airway management. Training of junior team members should be carried out by simulation on a regular basis, with full donning of PPE, to handle airway contingencies in case of the absence of senior experienced personnel.

Healthcare workers with comorbid conditions, that is chronic kidney disease, cardiac illness, diabetes and hypertension, chronic obstructive pulmonary disease, malignancy, on immunosuppressive therapy, pregnant females, and those aged older than 60 years are considered to be at high risk of contracting the disease and should not be part of airway management team.¹³

Intubation team generally consists of four to six members, all doing designated tasks.¹⁴ This might increase the risks of transmission. In patients with known or suspected COVID-19 disease, the number of people handling the airway should be restricted to three. If additional members are needed, they should ideally remain outside the room, where the patient is managed and enter the room only in special emergent circumstances, after donning full PPE. Team members should be trained in effective closed loop communication, to avoid distress, while performing high-risk procedure and during unanticipated difficulties.

Disposable vs Reusable Airway Equipment

It is prudent to use disposable (single use) equipment for airway management considering the risk involved in sterilization and disinfection and also transmission of virus while transporting the equipment. However, this might not be cost effective, and resources such as videolaryngoscopes and bronchoscopes might become scarce as the pandemic grows. Therefore, every institution should formulate local protocols for transport of the used equipment to the central sterile services department (CSSD) and its storage there. It is advisable to have a container filled with 1% sodium hypochlorite and 2% glutaraldehyde within the ICU so that the equipment can directly be placed in the disinfectant before initiating appropriate sterilization.

Barrier Devices

Creation of a physical barrier between the patient and person handling the airway has been explored as a method to reduce exposure to aerosols in COVID-19 patients. Multiple such devices have been tried since the beginning of the pandemic.^15–17

Canelli et al. have described a barrier enclosure device called as aerosol box.¹⁷ It is a transparent plastic cube that covers the patient’s face with two circular openings through which the clinicians can place his hands and perform the procedure. The major drawback for use of aerosol box is restriction of the hand movements of the operator, thus potentially making airway management more difficult. To overcome this restriction, it is suggested to modify the chamber with one large rectangular opening end to end in the head end of the cube rather than two openings in the sides. But this might increase the risk of transmission of infection. Also, the device has been criticized, as it only redirects the aerosols away toward the foot end of the patient and might still infect the other team members in the room. The device has a potential to increase the difficulty in TI, especially in emergent situations. Innovations to the aerosol chamber have been described. One such innovation includes use of protective long-sleeve gloves in the barrier device with plastic drapes to further reduce transmission. Another innovation suggested is putting of mobile flaps over the foot end of box (Fig. 1).

The other barrier device described is use of simple plastic drapes covering the face and torso of the patient. While single plastic drape over the patient is much easier to apply, a triple-panel plastic drape technique has been shown to minimize aerosol transmission. In this technique, one drape is placed below the patients head, second covering neck and chest, and third overhead drape with as sticky edge at level of mid sternum.¹⁵ Such extensive draping of the patient might cause distress to the patient and increase agitation, when they are awake before intubation (administration of drugs), and therefore complicate airway management.

A portable negative flow isolation chamber was described by Cubillos et al.¹⁶ It is a cubical tube frame measuring 60 × 60 × 60 cm, covered by transparent plastic. There are ports for oxygen and suction (to create negative pressure) on the side. The central bar in the middle allows placement of hooks on which equipment can be attached. The prototype is designed to minimize the risk of aerosol, and it can be customized according to the needs and local expertise (Figs 2 and 3).

In resource-limited settings, and while handling airway outside the ICU, barrier devices might not be available. In such situations, applying plastic drapes over the bed railings is an easy way to minimize risks (Fig. 4)

Albeit multiple such devices have been described, none of them have been proven to reduce transmission of aerosols. Nonfamiliarity with the device might make handling of airway much more difficult, and training by simulation should be done on a regular basis. The authors do not recommend for or against the use of any such device, and the airway team should use the device they are familiar with. In emergent situations, should the airway management become more difficult, the airway manager should not hesitate to remove the device altogether to secure the airway. During TI, these devices will get contaminated and appropriate decontamination protocols should be developed and practiced.

Preparation: Airway Cart

A dedicated COVID-19 airway cart should be prepared and checked by a senior airway manager, using a checklist, at the time of every change of shift. It should contain all essential equipment necessary for intubation and emergency cricothyroidotomy (Box 2). A cardiac arrest cart or resuscitation cart should always be kept just outside the room where the patient is being managed.

Preparation: Assessment of Airway

Airway assessment should be performed for every patient and should be clearly documented and communicated between clinicians in every shift. This would help in preparing individualized airway strategy for the patient. MACOCHA score (Box 3) or HEAVEN criteria (Box 4) are easy and reliable methods for assessing difficulty in intubation in ICU.^18,19 If the treating team is not familiar with these scores or criteria, they can use any other scoring system for predicting difficult airway, with which they are familiar.

Preparation: Intubation Team

The number of team members inside the intubation room should be restricted to 3. The senior most airway manager should be on the head end of the patient. The second operator, usually designated as airway assistant, should be on one side of the patient. The third team member is the person who administers drugs and monitors the vitals of the patients. One more team member, called the runner, should stand immediately outside the room for getting additional equipment or help (Fig. 5).

Preparation: Airway Plan

All the team members should be familiar with the airway management strategy for the patient and the trigger for moving from one plan to the next (such as use of bag and mask ventilation or supraglottic airway and emergency cricothyroidotomy). Urgent intubation is best avoided and the team should have adequate time to discuss airway plan and don protective gear for intubation.

Preoxygenation

In nonemergent situation, all patients should be preoxygenated for a period of 3 to 5 minutes. Preoxygenation should be done with face mask with tight-fitting seal connected to the ventilator or manual respirator. Bag and mask ventilation increases the risk of contamination and should preferably be avoided. In non-COVID-19 patients, noninvasive ventilation is commonly used for preoxygenation. This, however, is likely to generate high amounts of aerosol. Therefore, its use should be reserved for patients with severe hypoxia.²⁰ A viral filter should be attached directly to the face mask or as a connection with closed suction unit (Fig. 6). High-flow oxygen with nonrebreathing masks and reservoir bags are not recommended due to increased risk of aerosol generation and suboptimal preoxygenation. A well-fitted high-flow nasal cannula (HFNC) oxygen has shown to produce less aerosols when compared to coughing in experimental trials.²¹ Nevertheless, these are only experimental studies. As stated previously, viral load of patients could vary, and therefore high-flow nasal cannula cannot be recommended for preoxygenation in all COVID-19 patients. However, if the patient is previously on high flow nasal oxygen, it can be continued with a surgical face mask covering the patients face. High-flow nasal cannula oxygen should be stopped before the face mask is removed and the team takes the position for intubation. If the team plans to use either NIV or HFNC, it safer to do so in patients being managed in negative-pressure rooms. If a barrier device is used, it should be placed before initiating preoxygenation. Placement of a barrier device over an awake patient might increase agitation, and the patient should be clearly explained about the need for the device before its placement.

Rapid Sequence and Delayed Sequence Intubation

Rapid sequence intubation should be the default choice for TI. Cricoid pressure can be considered but if applied too early can precipitate cough. Also, it should be withdrawn if difficulty is encountered during intubation. In agitated and uncooperative patients, delayed sequence intubation can be considered. A sedative, mostly Ketamine at a dose of 0.5 to 1 mg/kg body weight, is used to reduce agitation and maintain spontaneous respiration. It helps in adequate preoxygenation and positioning of the patient and reduces combativeness.²² Use of a sedative can also help placement of a barrier device before preoxygenation.

Propofol, etomidate, or ketamine can be used for induction, based on the hemodynamic status of the patient. Rocuronium at a dose of 1.2 mg/kg or Succinyl choline at a dose of 1.5 mg/kg should be used for neuromuscular blockade, as high doses enable rapid achievement of neuromuscular blockade thereby preventing coughing and aerosol generation. If succinyl choline is used, it should be followed by a nondepolarizing muscle relaxant once TI is complete.

Oxygenation during Apnea and Manual Ventilation

In severely hypoxic COVID-19 patients, it is prudent to minimize the period of apnea. However, if the patient’s condition allows, complete apnea, without bag and mask ventilation, is preferred. Endotracheal intubation should be performed once adequate neuromuscular blockade has occurred. Patients with severe hypoxia might not tolerate even short durations of apnea and need manual ventilation during this period of apnea, produced due to administration of neuromuscular blocking drugs. In such patients, once the neuromuscular blocking agent is administered, a tight seal of the face mask should be achieved. A filter should always be placed between the mask and the circuit. Two-handed grip using C and E technique should be preferred over one-handed C and E technique to prevent leaks (Fig. 7). A two-handed V and E grip can also be used based on the comfort of the airway manager. Small tidal volume breaths should be delivered by the airway assistant. If the patient is connected to ventilator through a circle system, disconnection from the ventilator and connecting to a manual respirator might increase the risk of aerosol generation, and risks involved with such an approach should be kept in mind. A second-generation supraglottic airway should be considered for ventilation during apnea in place of bag and mask ventilation. A filter should be inserted over the supraglottic airway before commencing ventilation. Properly inserted second-generation supraglottic airways (such as ProSeal LMA, Supreme LMA, i-gel, SLIPA, and Laryngeal Tube) reduces exposure to aerosols and eases ventilation.

High-flow nasal cannula oxygenation should not be used (if it was not being used before) for apneic oxygenation due to risks involved to the staff.

Conventional vs Videolaryngoscopy

When an experienced operator familiar with videolaryngoscope use is available, videolaryngoscope should be preferred over conventional laryngoscope for TI. Videolaryngoscope offers multiple advantages over conventional laryngoscopy. It increases the distance between the operator’s head and patient’s airway. It improves the view on laryngoscopy, facilitates help from the airway assistant, and during difficult airway improves chances of first-pass success rate.^23,24 When using a videolaryngoscope with Macintosh blades or while using a conventional laryngoscope, it is prudent to use a bougie with preloaded endotracheal tube to improve first-pass success rates. We do not recommend for or against any specific videolaryngoscope, but videolaryngoscopes with integrated oxygen channels are best avoided to minimize aerosol exposure.²⁵ It is also preferable to use scopes with a separate screen so that the entire airway team can visualize the procedure and assist in any eventuality. If the airway manager is not familiar with use of videolaryngoscope, he or she should not use it for the first time in such a setting.

Use of Endotracheal Tube Clamps

Use of endotracheal tube clamps have been suggested to reduce exposure of HCWs to aerosols.²⁶ Albeit disposable clamps are in use, these are not universal, and surgical clamps (forceps) can be used instead to clamp the endotracheal tube before TI and extubation. If a clamped endotracheal tube is used, the clamps should be removed only after the endotracheal tube cuff is inflated, and the endotracheal tube is connected to the ventilator.

Confirmation of Correct Placement of Endotracheal Tube

Correct placement of endotracheal tube should always be confirmed by capnography. Experienced operators can consider using lung ultrasound for this purpose, that too, when capnography is not available. Three-point or five-point auscultation may not be possible with full PPE and could be hazardous for HCWs. Auscultation method also does not guarantee confirmation of correct endotracheal tube placement, and it is better to look at bilaterally symmetrical chest rise on ventilation as a good clinical indicator; however, it should not be considered as a replacement to capnographic confirmation.

Unanticipated Difficult Intubation

A detailed description of management of unanticipated difficult airway is beyond the scope of this document. Certain principles specific to COVID-19 would be discussed. A chart depicting options for management of unanticipated difficult airway, such as developed by any of professional societies, should be available with the airway cart.

When rescue bag and mask ventilation is performed, a two-handed C and E grip should be followed. Second-generation supraglottic airway should be used early in airway management to avoid risks of aerosol generation with bag and mask ventilation. If fiberoptic bronchoscopy-aided TI is planned, apneic oxygenation should be avoided. If bronchoscope is used through a supraglottic airway, then positive-pressure ventilation should be avoided.

Cricothyroidotomy is the method of choice for emergency surgical airway. Cricothyroidotomy should be performed by scalpel and bougie technique. Oxygen insufflation during the procedure both through needle and through nasal cannula and face mask increases the risk of aerosol generation and should be completely avoided. The committee does not recommend percutaneous tracheostomy as a rescue procedure but can be considered as a life-saving procedure in exceptional circumstances when expertise is available.

Tracheal Extubation

Risk of aerosol generation with extubation is the same as with intubation, and it is potentially more likely to transmit infection due to lack of neuromuscular paralysis and potential for coughing during extubation.^7,8 The barrier precautions for extubation should be same as that for intubation. Patient should meet standard extubation criteria. Patient should be clearly explained the sequence, and a barrier device should be placed. Plastic drapes or aerosol box can be considered. T-piece trial should be avoided, and the patient should be extubated directly from pressure support ventilation or continuous positive airway pressure. Assessment of power by asking the patient to cough should be completely discouraged. Instead, negative inspiratory force on the ventilator should be assessed for respiratory muscle efficiency. Tracheal suction should be performed using closed suction system. Performance of leak test to assess readiness for extubation is controversial. Leak test might increase the risk of aerosol generation and should be avoided. Once patient is extubated, it is prudent to apply a face mask immediately. The practice of nebulization immediately after extubation should not be performed, and the committee strongly recommends against such practice. We do not recommend for or against use of sedatives before extubation, and their use should be considered based on the patient’s clinical condition and expertise of the intensivist involved in extubation.

Percutaneous Tracheostomy

Awake percutaneous tracheostomy in nonintubated patients should not be performed in COVID-19 patients due to risk of aerosol generation, even when tracheostomy is clinically indicated. All efforts should be made to avoid coughing during procedure. It is recommended to use sedation and neuromuscular paralysis for this purpose. Videolaryngoscope should be used instead of conventional laryngoscope, for withdrawing the endotracheal tube. Ultrasound-guided tracheostomy is preferred over bronchoscopy guidance to minimize aerosol generation and also to minimize the number of HCWs involved in the procedure.

Flexible Fiberoptic Bronchoscopy

Bronchoscopy should be avoided for diagnosis of COVID-19 disease.²⁷ In patients with previous negative upper respiratory sample and high clinical suspicion, the World Health Organization recommends a lower respiratory sample for testing, as it has the highest sensitivity for COVID-19 diagnosis.²⁸ Albeit, the odds of aerosol generation with bronchoscopy is much less in comparison with endotracheal intubation,⁸ and in a non-intubated COVID-19 patient diagnostic bronchoscopy should be avoided. Awake bronchoscopy increases risk of cough, thereby aerosol generation. It also carries high risk of contamination with oropharyngeal and nasopharyngeal secretions.

In a hypoxic patient in the ICU, bronchoscopy can worsen hypoxemia. Risks involved in fiberoptic bronchoscopy for diagnostic purposes should be considered in such patients. Bronchoscopy, in ventilated patients, might also be needed for therapeutic purposes such as removal of mucous plug or blood clots. When indicated, to minimize the risk to HCWs, we recommend that bronchoscopy be done under sedation and preferably with neuromuscular paralysis. Before introducing the bronchoscope, we suggest that ventilation should be paused, endotracheal tube be clamped, and then the bronchoscope is introduced through the suction port of the catheter mount. Insertion of the bronchoscope through the main port of the catheter mount increases the exposure to aerosols and should not be practiced (Fig. 8). When indicated, it should be performed with full precautions, as needed for TI, with a barrier device.

Nebulization in COVID-19 Patients

The evidence about the risk of transmission of infection through aerosols generated by nebulizer is conflicting.⁸ Aerosols generated by a nebulizer is derived from a medication solution and is not a bio-aerosol as generated during a cough or sneeze. Nevertheless, during nebulization, large amount of droplets are generated, and this increases the risk of contamination of the nearby environment. Hence, nebulization should be used only in patients with absolute indications and with full precautions in negative-pressure rooms.

Airway Suction in Ventilated COVID-19 Patients

Open suction increases the risk of transmission to HCWs, and it is not recommended. All ventilated patients should be connected to a closed in line suction unit for tracheal suctioning. When the suction device is changed, ventilation should be paused, endotracheal tube should be clamped, and the device should be changed. Care must be taken to minimize disruption in the ventilatory circuit.

Airway Management during Cardiopulmonary Resuscitation

The ethical concerns about cardiopulmonary resuscitation (CPR) are beyond the scope of this document. Chest compressions and defibrillation have been shown to increase the risk of aerosol generation, although the evidence is debatable.^8,11 Minimal staff should be present during resuscitation with full PPE. Bag and mask ventilation should be avoided, and early advanced airway using a second-generation supraglottic device or endotracheal intubation should be considered. American heart association has suggested interruption of chest compressions to secure an advanced airway, and once endotracheal intubation is achieved, a HEPA filter should immediately be connected to the endotracheal tube. It is also recommended to ventilate the patient using the ICU ventilators.