**Abstract**

2020 has seen the whole world battling a pandemic. Coronavirus Disease 2019 (COVID-19) is primarily transmitted through respiratory droplets when in close contact with an infected person, by direct contact, or by contact with contaminated objects and surfaces. Aerosol generating procedures (AGPs) like intubation have a high chance of generating large concentrations of infectious aerosols. AGPs potentially put healthcare workers at an increased risk of contracting the infection, and therefore special precautions are necessary during intubation. The procedure has to be performed by an expert operator who uses appropriate personal protective equipment (PPE). Modifications of known techniques have helped to reduce the chances of contracting the infection from patients. The use of checklists has become standard safe practice. This chapter looks at the current knowledge we have regarding this illness and how we should modify our practice to make managing the airway both safer for the patient and the healthcare workers involved. It addresses the preparation, staff protection, technical aspects and aftercare of patients who need airway intervention. It recommends simulation training to familiarize staff with modifications to routine airway management.

**Keywords:** coronavirus, airway management, intubation, covid 19, novel virus, aerosol generating procedures

#### **1. Introduction**

The current outbreak of the novel coronavirus (Severe Acute Respiratory Syndrome Coronavirus 2 – SARS CoV-2) (COVID-19) was first reported as a cluster of pneumonia cases on Dec 31st, 2019 from Wuhan, Hubei province, China. The World Health Organization (WHO) declared COVID-19 as a public health emergency of international concern (PHEIC) on Jan 30th, 2020, and on March 11th, 2020 WHO characterized the spread of coronavirus as a pandemic.

We know that COVID-19 is primarily spread through respiratory droplets when in close contact with an infected person, or by contact with contaminated objects and surfaces. This puts healthcare workers attending to an infective patient at risk of contracting the illness, and airway management, being an AGP, would be the riskiest of all interventions. AGPs like intubation have a high chance of generating large concentrations of infectious aerosols. Therefore, special precautions are necessary during intubation. The procedure has to be performed by an expert operator who uses personal protective equipment (PPE) such as FFP3 or N95 masks, protective goggles, disposable long sleeved gowns, disposable double gloves and leg coverings. It is important to recognize mask ventilation and open suctioning of airways as AGPs. If possible, thorough preoxygenation and a rapid sequence induction and intubation (RSII) should be performed. Heat and moisture exchanger (HME) must be positioned between the mask and the breathing circuit or between the mask and the ventilation balloon. Personnel involved in the room should be kept to a minimum and this should be decided beforehand. Small changes to what we know as conventional airway management has been studied and improved upon to keep both COVID 19 patients and staff looking after them safe. This chapter looks at the details inside operating theater and kindly note that the airway management of COVID 19 patient in Intensive care settings are discussed in much details in other chapter in this book.

intubation challenging [8]. In COVID 19 patient's general recommendation for airway assessment will apply when it is possible and unanticipated difficult airway

*Airway Management in COVID-19 as Aerosol Generating Procedure*

COVID 19 patients are critically ill which preclude standard airway assessment.

History: previous difficult intubation history, last meal, previous critical events, smoking, drooling, dysphagia, recent burn in face or upper respiratory system, head

Investigations: X-Ray, USG (ultrasonography), CT, MRI, nasal endoscopy, 3D &

Many score systems and tools have been developed to predict difficult airway;

The most important recommendation for health care provider who will take a history or will do examination of the airway of suspected or infected COVID 19, is

Health care workers (HCW) are at a high risk to be infected with SARS-COV-2 (COVID 19) in particular during any aerosol generating procedures. As discussed before the main transmission route appears to be by respiratory droplets and contact transmission. Not surprisingly these droplets have very high virus load [13]. In view of this protecting personnel who are managing airways in COVID 19 patients must be at the most priority. Aerosol generating procedures vary in their ability to infect HCW but intubation tracheostomy, non-invasive ventilation (NIV) and bag

All efforts should be made to protect HCW providing airway management this will include many aspects to keep in mind. We can summarize them as

**The 6 D** methods (**Table 1**): [10], **LEMON** score system (**Table 2**) [11] **MMMMASK** mnemonics (**Table 3**), or **OBESE** mnemonics (**Table 4**). (**please**

The difficult airway is "*the clinical situation in which a conventionally trained*

*anaesthesiologist experiences difficulty with facemask ventilation, difficulty in supraglottic device ventilation, difficulty in tracheal intubation or all three"* [9].

Physical examination: mouth, face, neck, teeth, Mallampati score.

should be kept in mind.

**The difficult airway is defined as:**

*DOI: http://dx.doi.org/10.5772/intechopen.96889*

or neck trauma, OSA, snoring hoarse voice stridor.

**refer to other book's chapters for more details).**

**5. Personal protection and optimal environment**

mask ventilation (BMV) appear to carry the highest risk [14].

• Minimizing health care workers during active procedure

• Full PPE (personal protective equipment)

• Surface decontamination

• Negative pressure room

• Waste management

• Equipment decontamination

Virtual Endoscopy (VE), can be used for airway assessment.

to wear full PPE to protect himself or herself from the infection.

**4.1 Steps for airway assessment**

useful tools might be used like:

following:

**3**

#### **2. Epidemiology**

Corona virus pandemic has evolved since December 2019 in Wuhan, China. Starting from Wuhan the novel virus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) invaded all the over the globe [1], causing corona virus disease 2019 (COVID 19) [2]. As of July 2020, infected cases are increasing incredibly around the world. Based on current real-time reports, the estimated infected cases is fifteen million cases reported and more than 610.000 deaths worldwide [3]. The number of infected cases is expected to increase as the second peak is rising in most countries.

#### **3. Transmission**

COVID19 pandemic started as an outbreak in Wuhan with mainly transmission from animal to human. This theory was raised after most primarily infected people had visited or worked in seafood the market at Wuhan [4], and later on person to person transmission has been identified [5].

It is well known today that corona virus transmission is established by droplet. This is simply droplets with size 5–10 micron that can carry the virus. However till there is now no clear evidence to support airborne transmission (droplets size less than 5 micron which can carry the virus and able to remain in air for a period of time) but considering that this is still possible, the recommendation is to manage aerosols generating procedures as highly contaminating [6]. Experimental studies have revealed that the virus can be detected on different surfaces after these surfaces are exposed to the virus between 4 hours to 3 days depending on the surface type, the virus is more stable on plastic and stainless-steel surfaces [7].

#### **4. Airway assessment**

Airway assessment is recommended whenever there is airway management. Generally speaking the evidence behind airway assessment does not show high specificity nor sensitivity except for previous difficult intubation history, COVID 19 patients mostly need urgent or emergent interventions i.e. intubation. In these circumstances' airway evaluation is not always practical It is worth mentioning that most of these patients are critically ill. COVID 19 is known to cause laryngitis and upper airway oedema is not uncommon in this population which could make

*Airway Management in COVID-19 as Aerosol Generating Procedure DOI: http://dx.doi.org/10.5772/intechopen.96889*

intubation challenging [8]. In COVID 19 patient's general recommendation for airway assessment will apply when it is possible and unanticipated difficult airway should be kept in mind.

COVID 19 patients are critically ill which preclude standard airway assessment. **The difficult airway is defined as:**

The difficult airway is "*the clinical situation in which a conventionally trained anaesthesiologist experiences difficulty with facemask ventilation, difficulty in supraglottic device ventilation, difficulty in tracheal intubation or all three"* [9].

#### **4.1 Steps for airway assessment**

who uses personal protective equipment (PPE) such as FFP3 or N95 masks, protective goggles, disposable long sleeved gowns, disposable double gloves and leg coverings. It is important to recognize mask ventilation and open suctioning of airways as AGPs. If possible, thorough preoxygenation and a rapid sequence induction and intubation (RSII) should be performed. Heat and moisture exchanger (HME) must be positioned between the mask and the breathing circuit or between the mask and the ventilation balloon. Personnel involved in the room should be kept to a minimum and this should be decided beforehand. Small changes to what we know as conventional airway management has been studied and improved upon to keep both COVID 19 patients and staff looking after them safe. This chapter looks at the details inside operating theater and kindly note that the airway management of COVID 19 patient in Intensive care settings are discussed in much details in other

*Special Considerations in Human Airway Management*

Corona virus pandemic has evolved since December 2019 in Wuhan, China. Starting from Wuhan the novel virus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) invaded all the over the globe [1], causing corona virus disease 2019 (COVID 19) [2]. As of July 2020, infected cases are increasing incredibly around the world. Based on current real-time reports, the estimated infected cases is fifteen million cases reported and more than 610.000 deaths worldwide [3]. The number of infected cases is expected to increase as the second

COVID19 pandemic started as an outbreak in Wuhan with mainly transmission from animal to human. This theory was raised after most primarily infected people had visited or worked in seafood the market at Wuhan [4], and later on person to

It is well known today that corona virus transmission is established by droplet. This is simply droplets with size 5–10 micron that can carry the virus. However till there is now no clear evidence to support airborne transmission (droplets size less than 5 micron which can carry the virus and able to remain in air for a period of time) but considering that this is still possible, the recommendation is to manage aerosols generating procedures as highly contaminating [6]. Experimental studies have revealed that the virus can be detected on different surfaces after these surfaces are exposed to the virus between 4 hours to 3 days depending on the surface

Airway assessment is recommended whenever there is airway management. Generally speaking the evidence behind airway assessment does not show high specificity nor sensitivity except for previous difficult intubation history, COVID 19 patients mostly need urgent or emergent interventions i.e. intubation. In these circumstances' airway evaluation is not always practical It is worth mentioning that most of these patients are critically ill. COVID 19 is known to cause laryngitis and upper airway oedema is not uncommon in this population which could make

type, the virus is more stable on plastic and stainless-steel surfaces [7].

chapter in this book.

**2. Epidemiology**

**3. Transmission**

**4. Airway assessment**

**2**

peak is rising in most countries.

person transmission has been identified [5].

History: previous difficult intubation history, last meal, previous critical events, smoking, drooling, dysphagia, recent burn in face or upper respiratory system, head or neck trauma, OSA, snoring hoarse voice stridor.

Physical examination: mouth, face, neck, teeth, Mallampati score.

Investigations: X-Ray, USG (ultrasonography), CT, MRI, nasal endoscopy, 3D & Virtual Endoscopy (VE), can be used for airway assessment.

Many score systems and tools have been developed to predict difficult airway; useful tools might be used like:

**The 6 D** methods (**Table 1**): [10], **LEMON** score system (**Table 2**) [11] **MMMMASK** mnemonics (**Table 3**), or **OBESE** mnemonics (**Table 4**). (**please refer to other book's chapters for more details).**

The most important recommendation for health care provider who will take a history or will do examination of the airway of suspected or infected COVID 19, is to wear full PPE to protect himself or herself from the infection.

## **5. Personal protection and optimal environment**

Health care workers (HCW) are at a high risk to be infected with SARS-COV-2 (COVID 19) in particular during any aerosol generating procedures. As discussed before the main transmission route appears to be by respiratory droplets and contact transmission. Not surprisingly these droplets have very high virus load [13]. In view of this protecting personnel who are managing airways in COVID 19 patients must be at the most priority. Aerosol generating procedures vary in their ability to infect HCW but intubation tracheostomy, non-invasive ventilation (NIV) and bag mask ventilation (BMV) appear to carry the highest risk [14].

All efforts should be made to protect HCW providing airway management this will include many aspects to keep in mind. We can summarize them as following:



**Sign of difficulty Description Quantitative or qualitative**

*Airway Management in COVID-19 as Aerosol Generating Procedure*

Neck contractures secondary to burns or trauma

teeth disrupting the alignment of the airway axes and possibly decreasing the inte-rincisor gap

**6. Dental overbite** • Large angled

*DOI: http://dx.doi.org/10.5772/intechopen.96889*

*Shows 6 D methods for airway assessment: [11].*

**L Look externally:**

**E Evaluate:**

*Shows LEMON score for airway assessment [12].*

*Shows MMMMASK mnemonics difficult airway.*

**MMMMASK Description M** Male gender

**M** Mandibular **A** Age

**S** Snoring and OSA **K** Kilograms (weight)

**M** Mallampati grade 3or4

**Table 1.**

**Table 2.**

**Table 3.**

**5**

**findings**

**difficulty**

**LEMON Criterion Score**

• facial trauma • large incisors • beard or mustache • large tongue

• incisor distance • hyoid-mental distance • thyroid-to-mouth distance

**M Mallampati** 1 **O Obstruction** 1 **N Neck mobility** 1

**M** Mask seal which is affected by bread or being edentulous

**reported to be associated with**

Cervical spine collar or cervical spine immobilization

• Short, thick neck • Long, thin

• Dental overbite • No dental

**Acceptable findings not usually associated with difficulty**

neck

• No cervical spine collar or cervical spine

overbite


#### **Table 1.**

**Sign of difficulty Description Quantitative or qualitative**

tongue in relation to pharyngeal size

• Airway trauma (blunt or penetrating)

• Arthritic changes in the neck joints

Previous surgical airway

• Anterior larynx and decreased mandibular space

• Reduced mouth opening

• Limited head extension secondary to arthritis, diabetes, or other diseases

• Previous neck radiation and/or radical surgery

**3.Decreased thyromental distance**

**4.Decreased Inter-incisor gap**

**joint,**

**position**

**4**

**5. Decreased range of motion in any or all of the joints of the airway (i.e., atlanto-occipital**

**temporomandibular joints, cervical spine); atlantooccipital range of motion is critical for assuming the sniffing**

• Tissue consolidation (e.g., secondary to radiation)

**1. Disproportion** • Increased size of

*Special Considerations in Human Airway Management*

**findings**

**difficulty**

• Airway swelling • Possibly difficult to assess

**2. Distortion** • Neck mass • Voice changes • Mobile

trauma

**reported to be associated with**

• Blunt or penetrating airway

• Neck hematoma • Subcutaneous emphysema • Easily

• Neck abscess • Laryngeal immobility • Easily

• Nonpalpable thyroid cartilage

• Nonpalpable cricoid cartilage

• Distance between upper and lower incisors (i.e., inter-incisor gap) <4 cm (<2 finger breadths) • Mandibular condyle fracture • Rigid cervical spine collar

• Head extension <35° • Head

• Neck flexion <35° • Cervical spine

• Receding chin • No receding

• Thyromental distance >7 cm (~3 finger breadths) measured from the superior aspect of the thyroid cartilage to the tip

of the chin

• Tracheal deviation • No

• Neck asymmetry • No surgical

• Mallampati class III or IV • Mallampati

**Acceptable findings not usually associated with difficulty**

class I or II

• Midline trachea

> contractures of the neck

airway scar

laryngeal anatomy

palpated thyroid cartilage

palpated cricoid cartilage

• Thyromental distance ≥7 cm (3 finger breadths)

chin

• Inter-incisor gap <4 cm (2 finger breadths)

> extension ≥35° of atlantooccipital extension

flexion ≥35°

*Shows 6 D methods for airway assessment: [11].*


#### **Table 2.**

*Shows LEMON score for airway assessment [12].*


**Table 3.** *Shows MMMMASK mnemonics difficult airway.*


Negative pressure rooms with good rates of air exchange (> 12 exchanges per hour) is recommended to minimize risk of airborne exposure, in case not available portable HEPA filters or negative air flow, can be considered to reduce risk.

It is very important to have a clear plan for the airway management team. The plan should be discussed in detail with clarifying the rescue one in case unantici-

Staff who should avoid involvement in airway management: Immunocompro-

management for COVID 19 patients. Also, HCW above age of 60 years old mortality curve will increase remarkably in COVID 19 and patients with cardiac disease chronic respiratory disease; diabetes; recent cancer; and perhaps hypertension

**6. Non-invasive methods of ventilation in aerosol generating procedure**

Low-flow nasal oxygen (nasal cannula) may provide some oxygenation during apnoea (apnoeic oxygenation) and might therefore delay or reduce the extent of hypoxemia during tracheal intubation [21] however, literature suggests this beneficial effect might be worthless in patients with primary respiratory failure like in COVID 19 patients [22]. Till now, there is no evidence that low flow nasal canula can generate aerosols, in COVID 19 patients so, it is not recommended to use it

Using high flow nasal cannula (HFNC) 30–70 L/min significantly increases the risk of spreading exhaled gas [24], debate around using HFNC in COVID 19 considering it prolong apnoea time remarkably however there is few predisposed disadvantage: when used in deteriorating patients it is delaying intubation in severely ill patients who really need intubation, exhausting hospital oxygen reserves as a results in very high demand [25], when used during intubation risk of generating

**Important note:** after a few hours of ventilation by high flow nasal cannula (HFNC), the oropharyngeal airway and trachea become extremely dry, due to a high oxygen flow reaching 60 L/min. Which leads to difficulty in passing the endotracheal tube (ETT). So, make sure that the tube and the intubation equipment are very well lubricated to allow the tube to go easily through the vocal cords. Our personal experience is to soak the pharyngeal cavity with 10 ml 0.9% saline and

Data regarding use of non-invasive ventilation (NIV) in COVID 19 patients is limited but based on recent systematic review published recently the evidence

might reduce mortality and increase risk of healthcare worker transmission [27]. Many centres recommend to use NIV in view of limited resources in pandemic regions or using hyperbaric oxygen therapy in preventing mechanical ventilation in

for using NIV in COVID 19 patient is currently low in quality however it

mised or pregnant health care workers are advised not enroll in airway

*Airway Management in COVID-19 as Aerosol Generating Procedure*

that is why it is recommended to exclude HCW who have any of these

pated difficult airway management appear.

*DOI: http://dx.doi.org/10.5772/intechopen.96889*

co-morbidities [20].

**6.1 Nasal cannula**

routinely during intubation [23].

aerosol that carrying the virus [26].

*6.1.2 Non-invasive ventilation*

COVID-19 in other centers [28–30].

**7**

some gel to allow a sufficient lubrication for this purpose.

*6.1.1 High flow nasal cannula*

#### **Table 4.**

*Shows OBESE mnemonics for difficult mask ventilation.*

It is well known today that use of full PPE reduces the risk of infection in corona virus family [15], Based on retrospective study published on March 2020, hospital acquired infection was 41.3% from those 29% were health care workers from different specialties [16].

Level 3 (enhanced) is recommended in COVID 19 suspected or confirmed cases airway management for better understanding it is worth to mention here in summary what are the level of PERSONAL protection for healthcare workers [17] **(Table 5).**

The person who is performing the intubation should wear a third pair of gloves and remove them immediately after intubation [18].

Minimizing number of people during intubation is preferred in order to reduce risk of exposure. The interval time after intubation should be taken into consideration. The required waiting period will vary between 15 and 30 minutes [19].


#### **Table 5.**

*Levels of personal protective equipment (PPE) for healthcare workers when providing patient care. (copied from health protection Scotland, "levels of personal protective equipment (PPE) for ward patient care").*

*Airway Management in COVID-19 as Aerosol Generating Procedure DOI: http://dx.doi.org/10.5772/intechopen.96889*

Negative pressure rooms with good rates of air exchange (> 12 exchanges per hour) is recommended to minimize risk of airborne exposure, in case not available portable HEPA filters or negative air flow, can be considered to reduce risk.

It is very important to have a clear plan for the airway management team. The plan should be discussed in detail with clarifying the rescue one in case unanticipated difficult airway management appear.

Staff who should avoid involvement in airway management: Immunocompromised or pregnant health care workers are advised not enroll in airway management for COVID 19 patients. Also, HCW above age of 60 years old mortality curve will increase remarkably in COVID 19 and patients with cardiac disease chronic respiratory disease; diabetes; recent cancer; and perhaps hypertension that is why it is recommended to exclude HCW who have any of these co-morbidities [20].
