ABCs of COVID-19: Airway control, CPR, Basic/Advanced Cardiac Life Support with special regard to COVID-19 spread
It is well established that a substantial portion of patients with COVID-19 deteriorate, become critically ill and die eventually. Airway interventions are the ‘A’ of the alphabet of all resuscitative procedures, which can save the lives of the victims of COVID-19 and many other life-threatening emergencies. On the other hand, resuscitative procedures pose the greatest risk for disease transmission. Unlike many other personnel, one of the most important problems healthcare worker (HCW) face in CPR / ACLS is being unaware of the given patient’s infection status or contagiousness related to COVID-19. Aerosolization is triggered primarily by procedures including CPR, laryngoscopy, endotracheal intubation (ETI), ventilation management, and other advanced interventions. The use of personal protective equipment (PPE) is vital in all procedures and interactions with patients in pandemic period. For example, If ETI and ventilation is performed with a closed circuit, the risk of transmission is very low if a ventilator with high-efficiency particulate air (HEPA) filter is used. Mouth-to-mouth breathing is being abandoned in this pandemic era. The aim of this chapter is to highlight the indications and drawbacks of these maneuvers in the pandemic era, together with necessary protective measures for HCW.
Key words: COVID-19, cardiopulmonary resuscitation, basic life support, advanced cardiac life support, disease transmission, aerosolization, airway stabilization, tracheal intubation,
A substantial proportion of patients with COVID-19 are critically ill and some of them die. Patient factors, main strategies of the management, geographical differences, and perhaps subtypes of the virus affect these rates. Every healthcare worker (HCW) may encounter arrest status of a COVID-19 case at any time, which mandates a thorough knowledge and skills developed for each deadly scenario. For example, cardiotoxic effects of treatment agents such as hydroxychloroquine and azithromycin, which are frequently used in the treatment of COVID-19, induce QT prolongation which can trigger life-threatening arrhythmias in the vulnerable groups of patients.
Resuscitative procedures pose the greatest risk for disease transmission. Unlike many other personnel, one of the most important problems emergency HCW face in CPR / ACLS is being unaware of the given patient’s infection status or contagiousness related to COVID-19. This factor renders HCWs in primary care, EMS and EDs especially prone to be inflicted by the disease.
The use of PPE is vital in all procedures and interactions with patients in pandemic period. Applications precipitating aerosolization are primarily CPR, laryngoscopy- endotracheal intubation (ETI), ventilation management, i.e., NIV, PPV and other advanced airway interventions.
Recent evidence suggested that COVID-19 spread via respiratory droplets (i.e., particles greater than 5 μm) and possibly via aerosolization. The transmission occurs by means of respiratory droplets as well as through hand and surface contamination (Bowdle, 2020). Emergency airway manipulations offer the best chance for transmission of viral particles (Thiruvenkatarajan, 2020).
The viral load in the airway is presumably very high and hence poses significant infective transmission risk during airway management (Huang, 2020, Li, 2020). Occurrences in SARS-CoV outbreak in 2002 and 2003 suggests that the virus could be transmitted during aerosol-generating procedures, most commonly during ETI (Scalesi 2003, Loeb, 2004). In vitro findings suggest possible aerosol (<5 μm) transmission of SARS-CoV-2 (van Doremalen, 2020).
Many research findings are culminated to outline stability of SARS-CoV-2 in terms of aerosol and surface as compared with SARS-CoV-1 (van Doremalen, 2020).
A better understanding of association, interaction and transmission of the virus with ambient aerosols are the key to control its spreading for future prevention. This is particularly important as COVID-19 has still not subsided and there are second and third waves and even new strains of the same virus being reported in different parts of the world. In addition, there are a lot of factors affecting COVID-19 infection, such as underlying conditions involving immune system, behaviour, activity, and defense mechanism against infection of COVID-19 which play an important role to decide the fate of the virus within the human body.
Exposure dose, exposure time of an individual to the virus and the residence time (RT) of the virus is very crucial (Ram, 2021). The longer a virus stays in the atmosphere, the extent of protein denaturation and probability of infection will increase.
Evaluation of the association, interaction and transmission of SARS-CoV-2 virus with ambient aerosols is a key to understand its spread, carefully considering the recent experimental and field studies on the SARS-CoV-2 (Belosi, 2021). Moreover, the interaction of SARS-CoV-2 with a certain type of atmospheric aerosols having a specific chemical composition is very important (Contini, 2020).
Table 1. A comparison of viral load, distance travelled and #RNA copies ejected during exhaled breath of a seasonal influenza in 30 min (Adapted from Yan, 2018).
|Larger droplet||Smaller droplet|
|Distance travelled||<1 m||>2 m|
|Residence time (s)||300||30,000|
|Number of CoV-2/ droplet||1,000,000||1000|
|No. of droplets||1||1000|
|#RNA copies/30 min||1.20 × 104||3.80 × 104|
High-risk procedures include:
- Awake intubation should be avoided unless it is inevitable.
- Extubation: As a very high-risk procedure for aerosol and droplet spread, it needs elaborate preparation and detailed plans. Local guidelines should be followed to optimize clinical management and should be reevaluated at regular intervals.
- Bronchoscopy is one of the highest risk procedures for aerosol generation.
A consensus document was issued in March 2020 to provide clinical guidance and aid staff preparation for patients with COVID-19 in Australia and New Zealand. The authors highlighted a comprehensive list of sources generating aerosolization in airway management (Table 1).
Table 1. Sources of potential aerosol generation during airway management (Adapted from Brewster, 2020).
• Non-invasive ventilation or positive pressure ventilation with inadequate seal
• High flow nasal oxygen
• Jet ventilation
• Delivery of nebulized or atomized medications via simple face mask
• CPR (before intubation)
• Tracheal extubation
|Procedures prone to aerosolization||• Tracheal suction (without a closed system)
• Endotracheal intubation
• Bronchoscopy and/or gastroscopy
• Airway procedures on the neck (including tracheostomy, cricothyroidotomy)
Table 2. Risk factors for aerosol generation and protective maneuvers
|Risky situation||Protective approach and maneuvers|
|Unfitted face masks while pre-oxygenating the patient||• Well-fitting mask with HEPA filter|
|• Vice grip such as C-E hand position|
|• Bagging with a well-fitting bag-valve-mask device|
|• ETO2 monitoring to minimize duration for which face mask is applied by identifying earliest occurrence of adequate pre-oxygenation|
|Cough||• Don aerosol-protective PPE before entering procedure room and getting close to the patient|
|• Well-fitting mask with HEPA filter|
|• apply face mask with HEPA filter without wasting time after removing the patient’s protective mask|
|• Institute full paralysis before establishing airway control|
|• Management of extubation|
|PPV with inadequate seal||• Avoid PPV|
|‣ Face mask with adequate seal|
|‣ SGA of appropriate size, adequate depth of insertion and properly inflated cuff|
|‣ Confirm cuff of ETT distal to the cords, cuff manometry, well-secured ETT|
|‣ Bag the patient to gauge ventilation pressures|
|‣ Airway manometry to minimize plateau pressures|
|‣ Minimize required ventilation pressures — neuromuscular blockade, 45° head elevation, oropharyngeal airway|
|High gas flows||HFNO should be avoided|
Pulmonary micro- and macroscale tissue injury and damage in COVID-19
Respiratory failure is the outstanding cause of deterioration and death in patients diagnosed with COVID-19 worldwide. On autopsy studies and histopathologic examination of the lung specimens, diffuse alveolar damage and thrombotic microangiopathy have been pointed out as the most common findings (80 % and 60 %, respectively) (Sadegh Beigee, 2020). Pulmonary damage is developed after infection with COVID-19 that disrupts the alveolar airspace, interstitium and capillaries.