Intubation After Induction
Several specialty groups and societies have now addressed intubation approaches for the COVID-19 patient.[19,43,72–74] Taken together, these recommendations uniformly call for videolaryngoscopy as the primary intubation approach for patients with COVID pneumonia.
Although videolaryngoscopy is not new to routine or difficult airway management, the benefit in COVID-19 is that it allows physical distance between the provider's face and the patient's airway, thus potentially reducing the chance of exposure to droplet-based infection. Existing data suggest that use of videolaryngoscopy may also result in easier intubation performance with less failure and fewer attempts than direct laryngoscopy when used by an experienced provider. In difficult airway patients, videolaryngoscopy improves intubation success when compared to direct laryngoscopy.[19,75–78] Thus, for the COVID-19 patient with a difficult airway, it is thus logical to deploy dedicated airway teams facile with videolaryngoscopy for urgent tracheal intubation. A recent series of emergency COVID-19 tracheal intubations from Wuhan supports the use of videolaryngoscopy. A dedicated team of 54 anesthesiologists achieved a high success rate of tracheal intubation, mostly utilizing videolaryngoscopy.
Hyperangulated videolaryngoscopy does have some drawbacks when compared to direct laryngoscopy. If secretions or blood are present, then visualization through a dirty camera lens may be substandard. Also, the increased curvature of hyperangulated videolaryngoscopes can increase the difficulty of passing the ETT through the cords even if they are well visualized. Although such limitations are uncommon, patients who require intubation for COVID-19 are often in extremis and little time is available to switch to a different laryngoscope. This time constraint is even more acute when the airway is difficult. We thus recommend that airway managers have a direct laryngoscope readily available in case videolaryngoscopy fails.
Videolaryngoscopy by a skilled provider should be the primary laryngoscopic technique for asleep intubation of the difficult airway COVID-19 patient if available. If a provider is more skilled with direct laryngoscopy for difficult airway management, or if videolaryngoscopy fails, then those tools should be available as well (Figure 3).
Algorithms for awake tracheal intubation and modified rapid sequence induction. ETT indicates endotracheal tube; FIS, flexible intubation scope; HEPA, high-efficiency particulate absorbing filter; SGA, supraglottic airway.
Intubation Through an SGA
When initial attempts at intubation are unsuccessful, oxygenation with tightly sealed BMV and a HEPA filter may minimize aerosolization while placement of an intubating SGA is considered. Preferably, a second-generation SGA may be used due to its higher oropharyngeal leak pressure, allowing for higher respiratory pressure as well as possible drainage of regurgitated material.[80,81]
When FIS-facilitated intubation is planned via an intubating SGA, attaching a HEPA filter to the breathing circuit will reduce exposure to exhaled droplets and allow for the insufflation of oxygen throughout the intubation procedure. In addition, placement of an ETT with a bronchoscope adapter and inflation of its cuff within the SGA can reduce leaking during the procedure (Figure 2).
A nonintubating SGA may also be considered but requires the use of an intermediate Aintree Catheter and FIS. When the placement of the SGA is unsuccessful, perform BMV as described previously while preparing for emergency invasive airway management (Figure 2).
Use tight seal BMV to minimize aerosolization, and use of an intubating SGA (preferably second generation) to facilitate intubation.
If SGA placement is unsuccessful, then perform BMV as described previously while preparing for emergency invasive airway management.
Emergent Invasive Airway Management
Emergent invasive airway management (cricothyrotomy) may be necessary for COVID-19 adult patients if noninvasive airway management fails or in the "cannot ventilate, cannot intubate" (CVCI) or "cannot intubate, cannot oxygenate" (CICO) situation. Although recommendations for airway management are often based on patient, institutional, and geographic factors, many guidelines recommend a scalpel-based, open surgical airway for patients with COVID-19.[42,82]
A surgical airway is traditionally performed by making an incision through the skin, subcutaneous tissue, and cricothyroid membrane into the lumen of the trachea, followed by the insertion of an ETT. With respect to COVID-19, clinicians must balance the complexity and need for special equipment characteristic of many open surgical emergency surgical airway techniques with more simple surgical airway techniques.
For COVID-19 patients who require invasive surgical access, concerns include a high first-pass success rate, the least amount of patient harm, and to minimizing infectious risk to providers. Given the time-critical nature of the emergency invasive airway, the technique used should be as simple and rapid as possible, be well-rehearsed, and not require special equipment.
We believe that appropriate decision making, availability of equipment, technical ability, and human factors considerations are essential for the appropriate and successful performance of emergency invasive airway access techniques when a CICO event occurs. An experienced anesthesiologist, surgeon, or another experienced practitioner should perform the procedure (not trainees). In addition to full sedation/analgesia, adequate neuromuscular blockade should be provided to prevent coughing and resultant aerosolization of respiratory droplets.
We recommend the performance of the bougie-assisted cricothyrotomy or scalpel-bougie-tube technique in COVID-19 adult patients who require emergent airway rescue. Such an approach has a high success rate in non–COVID patients and should translate to patients with COVID-19.[88,89] Ventilation should be discontinued before opening the cricothyroid membrane and held until placement of the definitive airway. If difficulty is encountered in placing the airway and the patient needs to be ventilated again by a bag-valve-mask, then the cricothyrotomy opening should be occluded with a finger to prevent air leak. If the cricothyroid membrane cannot be located, then an open cricothyrotomy is recommended.
In non–COVID-19 patients, the need for invasive emergency airway has been associated with low survival rates. In the COVID-19 era, recovery from cardiac arrest has likewise been low. Because the performance of these invasive procedures increases HCW exposure to COVID-19 infection, the decision to include emergency invasive airway procedures in this process should be considered by each institution.
Use simple surgical techniques, such as the scalpel-bougie-tube cricothyrotomy, in airway emergencies requiring invasive airway access.
Refrain from using jet ventilation as it increases aerosolization of viral particles.
Discontinue ventilation immediately before the cricothyroid membrane puncture to minimize aerosolization through the cricothyroid puncture site.
Include a scalpel, ≤6.0 ETT, and adult bougie as equipment in the difficult airway cart.
Technical competency and familiarity with emergency invasive airway access techniques may improve the successful management of emergent airway rescue situations.
ETT exchange or manipulation may be needed in COVID-19 patients due to cuff rupture, inadvertent extubation, or acute ETT obstruction caused by thick secretions and/or sloughed tracheobronchial tissues and inflammatory cells. Such obstruction may limit the ability to oxygenate and ventilate and places the patient at risk for further desaturation. In patients with a difficult airway, this risk is increased as the time needed to change the ETT may be prolonged. The procedure may increase HCW exposure to aerosolized secretions.
To minimize exposure and increase the rate of success, patients should be fully paralyzed and sedated during the procedure. An airway exchange catheter (AEC) is recommended to facilitate ETT exchange and a bronchoscope adaptor placed between the ETT and ventilator circuit will allow an AEC to be used with less aerosolization of secretions. As patients may have airway edema, and to reduce the duration of extubation or aerosolization, a videolaryngoscope is recommended during tube exchange to improve visualization of the glottis and passage of the new ETT during exchange (Figure 4).
Algorithms for extubation for difficult airway and endotracheal tube exchange. AEC indicates airway exchange catheter; COVID-19, coronavirus disease 2019; ETT, endotracheal tube; FIO 2, fraction of inspired oxygen; HEPA, high-efficiency particulate absorbing; VL, videolaryngoscope.
Use an AEC through bronchoscope adapter between ETT and ventilator circuit.
Use videolaryngoscope during ETT exchange.
The risk of contamination during extubation is potentially even higher than for intubation, as muscle relaxation has been reversed, and the patient is spontaneously ventilating and may cough or exhale forcefully. A recent study of aerosolization during perioperative airway management found more detectable aerosol (15-fold) during extubation when compared to intubation. Complications that occur during extubation, such as stridor, laryngospasm, or acute airway obstruction, may require positive pressure ventilation by mask and reintubation, which generate aerosols.
Risk factors have been described for complications during extubation.[95,96] These risks include difficult reintubation and anatomical changes that increase concern for difficult reintubation, such as airway edema and restricted access to the airway. COVID-19 patients displaying any of these characteristics should be considered at high risk for extubation.
In the context of a difficult airway, the COVID-19 patient may be difficult to reintubate, with the associated increased risk of provider exposure; therefore, an awake extubation is recommended. While asleep extubation may reduce coughing, we believe the risks outweigh that benefit.
Periextubation coughing increases aerosolization risk and may be reduced with lidocaine administered IV or topically to the vocal cords, or by injecting into the ETT cuff. A recent meta-analysis found less coughing with dexmedetomidine compared to remifentanil or fentanyl, and that all 3 medications were superior to no treatment.
Preparation and recommendations for extubation of suspected or confirmed COVID-19 patients can help reduce coughing or protection of secretions during extubation.[92,98–102] Taking into consideration the risks of extubation in the setting of a difficult airway and COVID-19, the following steps to reduce risks and complications are reasonable (Figure 4):
Consider the administration of medications to reduce coughing.
Consider the administration of medications to prevent nausea and vomiting.
Assess the risks versus benefits of deep extubation in COVID-19 patients with a difficult airway.
Consider awake extubation in COVID-19 patients with a difficult airway.
Anesth Analg. 2021;133(4):876-890. © 2021 International Anesthesia Research Society