Airway management in suspected COVID-19 cases - by Dr. Jebu A Thomas

Coronavirus disease 2019 (COVID-19) is defined as illness caused by a novel coronavirus. It was initially reported in Wuhan City, China in December 2019 and WHO declared COVID-19 as a pandemic in March 2020.

COVID-19 suspected patients may present with uncomplicated (mild) illness as well as with severe disease. As per the initial reports, 81% of patients have mild (absent or mild pneumonia), 14% have severe (hypoxia, dyspnoea, >50% lung involvement within 24-48 hours), 5% have critical (shock, respiratory failure, multiorgan dysfunction), and 2.3% have fatal disease. Patient with severe, critical and fatal disease is the people who need airway management, especially patients having type 1 respiratory failure, ARDS, septic shock or MODS.

Rapid sequence intubation is the method of choice for securing airway in the Emergency Department. While managing airway of patient with COVID-19, in addition to the conventional 7 P’s of RSI, an eighth ‘P’ should be considered i.e. Personal protection. Personal protection includes the provider safety which should be given utmost care and considering this, the nomenclature RSI (Rapid sequence intubation) may be renamed as protected intubation. The 8 P’s of protected intubation is given in Table 1

1	Personal Protection
2	Preparation
3	Preoxygenation
4	Pre-treatment
5	Paralysis and sedation
6	Position
7	Placement of tube
8	Post Intubation care

Table 1: 8 P’s of Protected Intubation

There is no high-level evidence for these modifications – at best the evidence is Level C – consensus/expert opinion

1. Personal Protection

Protection of team is most important while taking care of COVID19 patient, hence the patient should be provided a 3-ply surgical mask (Fig 1) so as to minimise droplet spread as soon as he enters the health care facility.

Figure 1: Patient with 3-ply surgical mask

Airborne Infection Isolation Room (AIIR) is ideal for any aerosol generating procedure (AGP). If AIIR is unavailable, normal pressure room with strict door policy should be the norm.
All persons taking care of the patient should wear Level 3 PPE is to be worn for any AGP. List of AGP is given in the table below (Table 2). It is advisable to wear 3 pairs of gloves and the outermost glove should be removed soon after intubation so as to minimise soiling of other areas. To prevent shield/ fogging, it would be better to cover the inner side of shield/ goggles with a layer of transparent hand sanitizer. 

Table 2: Aerosol Generating Procedures (AGP)
Cardiopulmonary resuscitation	Bag valve mask ventilation
Non-invasive positive pressure ventilation	High flow nasal cannula
Intubation and Extubation	Nebulisation
Bronchoscopy	Tracheostomy
Suctioning	Cricothyroidotomy
Oro/ Nasopharyngeal swab collection	Dental procedures involving high speed drill

Minimum number of personnel’s (3 person) inside the room and a person should be just outside the room as a runner (In level 3 PPE) who will work as an assistant if needed.
Anything entering within 2 meter radius of patient should be considered as contaminated (Fig  2).

Figure 2: Area of contamination around the patient

If the patient is not provided a mask, this radius increases as droplet (Fig 3) or airborne (Fig 4) spread increases especially when patient coughs or sneezes. Minimise physical contact when working around the patient.

Figure 3: Droplet spread

Figure 4: Aerosol spread

2. Preparation

It is ideal to have a pre-prepared COVID intubation tray (Fig: 5, 6,7,8) which will have

all the equipment’s including equipment’s for failed airway. It is ideal to have two

functional IV access (preferably in proximal large vein). Meticulous airway assessment

and plan for failed airway should be done during the preparation phase and all the team

members should be well aware of the plan for intubation. Rough layout of room for

airway management is depicted in figure 9.

Figure 5: 2 tested laryngoscopes with appropriate blades, Bag Valve Mask with filter fitted just distal to mask, appropriate sized ET tube, nasal prongs for apnoeic oxygenation, non-rebreather mask for preoxygenation. Video laryngoscope (not shown in the picture) with dedicated monitor.

Figure 6: Gauze pack, ET tube tie, Nasogastric tube, Lubricant jelly, Stethoscope, crystalloid, premedication agents, paralytic agents, induction agents, push dose pressor and post intubation sedation and analgesia

Figure 7: Stylet, gum elastic bougie, supraglottic airway device, oropharyngeal airway and McCoy laryngoscope blade as rescue devices in failed airway plan.

Figure 8: eFONA set – comprising of No: 11 scalpel blade, gauze pack, Cuffed 5.5 or 6 size ET tube and tracheostomy tube

Figure 9: Room layout

3. Preoxygenation

Passive preoxygenation should be done for minimum of 5 minutes. Position the patient

for preoxygenation by keeping the head elevated by 25-45 degree. Separate oxygen

source for preoxygenation with Non rebreather mask (NRBM) kept at a flow rate of

10-15L/min (Fig 12) and for apnoeic oxygenation with nasal cannula kept at flow rate

of 4-6L/min (Fig 13) (NODESAT – Nasal oxygen during efforts securing a tube).

NRBM to be kept over the 3-ply mask to minimise aerosolization (Fig 10). Lowest

possible gas flow should be used to maintain oxygen saturation above 92%. VAPOX

(Ventilator Assisted PreOXygenation) should be avoided as far as possible and if at all

used, a non-vented NIV mask should be used and filters should be incorporated in the

circuit. Noncompliance of patient for preoxygenation may be mitigated by the use of

dissociate dose of Ketamine (0.5-1mg/kg).

Bag valve mask device with viral filter can be used for preoxygenation but positive

pressure ventilation should be avoided as far as possible. Instead of E-C clamp

technique, a 2 hand Vice grip (V-E grip) gives a better seal and is the preferred method

(Fig 14, 15). A better seal is obtained by using NIV mask (non-vented) strapped to the

patient (Fig  16). This should also have a filter proximal to the mask.

Oxygen source should be turned off before removing the mask so as to ensure provider

safety.

Figure 10: 3-ply surgical mask over which NRBM is applied

Figure 11: Graph showing aerosol dispersion while using various modalities of treatment

HFNC is the preferred non-invasive method of oxygenation. As seen in the above graph (Fig 11) HFNC is thought to increase the risk through aerosolization, but in combination with a mask placed on top of cannula, it is thought to be safer than CPAP/BiPAP. Patients who are on HFNC should be monitored closely and consider up titration of treatment early in the course of disease (consider calculating ROX index).

Figure 12: Nasal prongs for apnoeic oxygenation (3-ply surgical mask not shown in the picture)

Figure 13: NRBM for preoxygenation along with nasal prongs (3-ply surgical mask not shown in the picture)

Figure 14: Double E-C Clamp technique giving head tilt chin lift

Figure 15: V-E technique giving jaw thrust

Figure 16: Bag valve mask with reservoir bag fitted with a NIV mask (non-vented) and filter proximal to the mask

4. Pre-treatment

Antimuscarinic agent Glycopyrrolate 0.2mg IV may be used to decrease secretions. Lidocaine 1.5 – 2

mg/kg IV to be used to decrease the incidence of coughing during intubation. When bronchospasm is

a concern, it is prudent to use metered dose inhaler rather than nebuliser in order to decrease the risk

of aerosolization.

If time permits, adequate hemodynamic resuscitation should be the norm and consider fluid-sparing

approach due to concerns for third-spacing. Prior to induction, consider having vasopressors

prepared/ running (norepinephrine 5-35 mcg/min) – particularly for patients with hypotension, signs

of impaired perfusion, or elevated shock index (HR÷SBP > 1) or keep push dose pressor handy and

use it as a bridging agent for buying time to initiate pressor infusion if patient becomes

haemodynamically unstable.

5. Paralysis and induction

Ketamine 1– 2mg/kg of ideal body weight or Etomidate 0.15 – 0.3mg/kg of total body weight are the

preferred induction agents. Lower doses of induction agents (aliquots of 0.5mg/kg of Ketamine until

sedation is achieved) are ideal in haemodynamically unstable patients so as to prevent post intubation

adverse events.

Succinylcholine 1.5 – 2mg/kg of total body weight or Rocuronium 1.2 – 1.6mg/kg total body weight

are the preferred paralytic agents of choice. Rocuronium has an added advantage of longer safe

apnoea time compared to Succinylcholine. Higher dose of muscle relaxant to be considered in

haemodynamically unstable patient. Complete paralysis should be ensured before intubating so as to

prevent coughing.

6. Position

Sniffing position is the conventional position for intubation but variations may be tried as per the skill

of the provider. Bed Up Head Elevated (BUHE) position is one such modification which can be done

which gives an added advantage of better oxygenation and longer safe apnoea time (Fig 17, 18, 19

20).

Figure 17: Bed kept flat

Figure 18: Foot end elevated (Trendelenburg position)

Figure 19: Head end elevated to 30 degree

Figure 20: Head roll under the neck

7. Placement of tube

Intubation to be done by the most experienced person in the team and preferably with a video laryngoscope so as to increase the distance between the provider and the patient. Use barrier enclosure if available or transparent polythene sheet so as to contain droplet spread. Intubation should be done beneath the polythene sheet (Fig 21). Proximal end of the ET tube should be plugged with gauze so as to minimise contamination (Fig 22). If bougie is preloaded then also the proximal end of tube should be plugged with gauze (Fig 23). Kiwi grip may be tried so that the airway assistant need not come in close proximity to the patient (Fig 24). Tube is to be fixed at a premeasured length. Visualisation of black line passing through the cords so as to make sure it’s endotracheal. Confirming the depth of the endotracheal tube is extremely difficult using auscultation while wearing isolation suits. It is recommended instead to observe bilateral chest expansion, ventilator breathing waveform, and respiratory parameters. End-tidal CO2 is a better indicator of successful tracheal intubation, as oxygen saturation is not always increased immediately after intubation in these patients, because the oxygen exchange is significantly impaired. Bedside ultrasonography is another modality which can be used for confirmation of ET tube position. Cuff is to be inflated before initiating ventilation and cuff pressure to be monitored so as to minimise leak. Remove outer glove soon after intubation to limit contamination.

Figure 21: Transparent polythene sheet beneath which intubation is being done so as to minimise droplet spread

Figure 22: Prechecked ET tube preloaded with malleable stylet and proximal end plugged with gauze

Figure 23: ET tube preloaded with gum elastic bougie and proximal end plugged with gauze

Figure 24: Kiwi grip so as to minimise the number of personnel coming in close proximity to the patient

8. Post intubation care

Analgesia first followed by sedation so as to prevent patient machine asynchrony.

Opioid as analgesic and benzodiazepine as a sedative agent as per the haemodynamic

profile of the patient will be ideal. Avoid unnecessary ventilation disconnection. If

disconnection is needed, put PPE, put ventilator on standby and clamp ET tube.

Disconnection of circuit should be done distal to the filter. Use closed suction

whenever possible. Ventilatory parameters should be pre-set should be a part of the

preparation phase (Fig 25). Both the limbs of circuit should have filters. Initial

ventilator settings include Volume assist control mode with tidal volume of 6cc/kg

IBW, Inspiratory flow to be kept between 60-80L/min respiratory rate of 16-18 breaths

per minute, FiO2 100%, PEEP of 5cm H2O which should be titrated as per ARDSnet

protocol. Saturation should be maintained above 96% and plateau pressure to be

maintained below 30cm H2O.

Nasogastric tube to be inserted after patient is being ventilated safely. After the

procedure, discard the disposable items properly and proper disinfection of reusable

items should be done. Doffing should also be done in a proper manner.

Figure 25: Ventilator pre-set and filters in both inspiratory and expiratory limb of circuit

Failed Airway

In the event of a failed intubation attempt [Cannot Intubate Cannot Ventilate (CICO)], a second generation supraglottic airway device (SGD) should be used as a temporary bridging method. Proximal end of SGD should be plugged with gauze so as to minimize contamination (Fig: 26). Ventilation should be commenced only after ensuring that appropriate sized SGD is fixed at adequate depth, and the cuff is fully inflated.

Figure 26: Supraglottic airway device with proximal end plugged with gauze

Emergency Front of Neck Access (eFONA) – scalpel bougie technique to be considered early in the course of failed airway

Cardiopulmonary resuscitation

Prearrest

If at risk of cardiac arrest, consider shifting the patient to negative pressure room proactively to minimize exposure. Close the door to prevent adjacent area contamination if negative pressure room is unavailable.

Considerations before initiating cardiopulmonary resuscitation

1    Is it too late?

Mortality from cardiac arrest secondary to COVID19 is approximately 13% which is caused by hypoxaemia and/or myocarditis. Reconsider resuscitation if in end stage disease state.

2    What about Do Not Resuscitate Status?

Consider DNR status before attempting resuscitation as the severity of illness is more in elderly age group as well as with comorbid illness.

3    What about the adequacy of Resources?

In a pandemic where resources are outnumbered by needs, think before initiating a full-fledged resuscitation. When considering personnel’s and ventilators as a scarce resource, a prevented resuscitation can result in better resource allocation.

Considerations during cardiopulmonary resuscitation

3 persons should suffice for performing cardiopulmonary resuscitation. Level 3 PPE (Disposable gown, gloves, FFP3 respirator and eye protection) should be worn by all team members especially when performing chest compression, Bag valve mask ventilation and intubation. So as to reduce the number of personnel’s, mechanical chest compression devices should be considered during resuscitation.

Intubation attempts should be minimized so the most experienced person in airway management should take care of the victim’s airway. Chest compressions should be paused during attempted intubation to improve the first pass success. Video laryngoscope should be the choice of equipment for intubation. After intubation, minimise disconnections of circuit so as to reduce aerosolization.

In instances where intubation is delayed, bag valve mask or supraglottic airway with a filter should be used for ventilation. A tight seal should be obtained during bag valve mask ventilation to reduce aerosolization.

Filter should be attached to a bag valve mask, supraglottic airway or before connecting to mechanical ventilator to reduce aerosolization. 

If already intubated at the time of cardiac arrest, don’t try to disconnect the patient from ventilator so as to maintain closed circuit. Ventilator settings such as FiO2, mode of ventilation, trigger, respiratory rate and alarms should be readjusted.

Considerations after cardiopulmonary resuscitation

While considering post cardiac arrest care, the conventional ABCDE approach should be applied. Apart from the conventional management things which should be considered are:

1    1. Optimise ventilatory settings according to the patient’s clinical condition.

2    2. Local infection control practises after resuscitation for doffing and patient transport. 


      
About the author: Dr. Jebu A Thomas (MBBS, DNB(EM), MRCEM, MNAMS) currently works as Assistant Professor in Emergency Medicine at Pushpagiri Institute of Medical Sciences, Thiruvalla, Kerala. He can be reached at dr.jebu@gmail.com