Table 1.

Main characteristics of included studies.

Recommendation	Chinese outcome analysis	Italian outcome analysis
Preoperative evaluation	All required equipments should be packed, disposable devices are recommended	Checklists, cross-checking and pre-planned strategies are recommended
Acronym	OH–MS MAID—Oxygen, Helper, Monitor, Suction, Machine, Airway supplies, Intravenous access and Drugs.	STOP COVID-Secure airway, Team briefing, Organize, Prepare, Checklist, Optimize, Vigilated donning/doffing, Invasive airways evaluation, Debriefing
Difficulties	Consider as potentially difficult and complicated tracheal intubation candidates	Consider the difficulties including triaging, personal protective equipment (PPE) and isolation areas
Noninvasive ventilation	Although there is a risk of aerosol-generation, bilevel positive airway pressure mode is widely used	As there is a risk of viral aerosolisation non-invasive ventilation may be insufficient and there may be a poor response
Awake tracheal intubation	No recommendation	Using videolaryngoscopy is faster than flexible bronchoscopy and should be considered In case of a failure tracheostomy with local anesthesia is recommended
Cannot intubate, cannot oxygenate scenario	No recommendation	An emergency front-of-neck airway should be performed
Tracheal intubation	Rapid sequence intubation and videolaryngoscopes are recommended instead of direct laryngoscopes. Experienced airway operator should be preferred. Chest auscultation after intubation is not recommended. Psychological pressure and burdens may cause challenges.
Muscle relaxants	Rocuronium 1 mg/kg or succinylcholine 1 mg/kg	Rocuronium 1.2 mg/kg or suxamethonium 1 mg/kg
Introducer	No recommendation	An appropriately sized tracheal tube introducer is advised
Apnoeic oxygenation	No recommendation	Low-flow nasal oxygenation is recommended during intubation attempts
Failed tracheal intubation	No recommendation	Second generation supraglottic device is recommended as a rescue technique.
Airway team	No recommendation	Team roles and ergonomics were described. Team-based simulation and training was mentioned.
Extubation strategies	The same precautions with tracheal intubation.	Tracheal tube exchange manoeuvres, and strategies were mentioned.