Is there a flowchart for steps of oxygenation

Posted on May 4, 2020 by Gemma Percival

Summary

On April 30, 2020 AIME released updated airway management guidelines,  which includes an oxygenation flowchart for patients with known or suspected COVID-19. 

I.   Airway management guidelines for patients with known or suspected COVID-19 (1)

The following algorithm was released by AIME Airway on April 8, 2020.

  • These recommendations, which are summarized below,  should be regarded as Level C evidence (limited evidence or expert opinion).   

AIME Airway Management Guidelines for Patients with Known or Suspected COVID-19

II.   Guiding principles (1)

  • “If possible, ‘do-not-intubate’ or ‘do-not-resuscitate’ status should be established prior to tracheal intubation of any, but especially the older and possibly co-morbid patient with COVID19 related respiratory failure;
  • Clinicians working in other countries’ ‘hot zones’ indicate that with the use of CPAP or HFNO, some patients have avoided the need for intubation altogether, while others have been adequately temporized while a ventilator was sourced. 
  • However, in COVID-19 patients in hypoxemic respiratory failure with a worsening trajectory despite escalating oxygenation measures (e.g. use of HFNO or CPAP) early tracheal intubation has been advocated. This holds the advantage of intubation performed under controlled, nonemergency conditions. Also, once completed, it might help protect the health care worker by minimizing further droplet spread from the patient or by avoiding use of potentially aerosolizing non-invasive modalities such as continuous positive airway pressure (CPAP) or high-flow nasal oxygen (HFNO). 
  • Staff safety is paramount, so that use of oxygen delivery and ventilatory support modalities such as CPAP or HFNO that are considered to be at risk of aerosol generation should ideally occur in a negative pressure AIIR and staff should wear full airborne/droplet/contact precautions. 
  • Regardless of delivery modality, the patient requiring oxygen supplementation should be closely monitored for deterioration. If needed, escalation to the next level should occur in a timely fashion. When tracheal intubation is indicated, it should occur in a controlled manner with close attention to staff safety. 
  • Some COVID-19 patients with respiratory failure can present with a profound degree of hypoxemia, yet seemingly few symptoms (the ‘silent’ or ‘happy’ hypoxemic patient): speaking in full sentences, without significant dyspnea and with normal mentation. These patients may be candidates for a brief trial of supplemental oxygen that includes CPAP or HFNO. • Others may have a more classic presentation of hypoxemia with tachypnea and high work of breathing, hypercarbia and tachycardia or with other signs such as confusion or hypotension. This population will likely require early tracheal intubation. 
  • Optimal oxygen goals are unknown, but a target SpO2 of 92-96% should be considered if feasible2 . If below 92%, escalation of oxygen therapy should be considered; if above 96%, reducing the oxygen flow rate can be considered, or de-escalation of the delivery modality to one with less potential for aerosol generation. Lower oxygen targets may be established for this disease going forward. 
  • The COVID-19 patient in hypoxemic respiratory failure appears to respond well to proning – both after intubation and before/without intubation, supplemented by modalities that range from nasal prongs/cannulae to CPAP. However, on resumption of the supine position, the patient may again desaturate. The team should be ready for this eventuality.”

III.   Initial oxygen supplementation (1)

O2 nasal cannula at flows < 10-15  lpm

  1. Standard nasal cannula < 5 lpm OR
  2. Design specific (non-humidified) high flow nasal cannula with flow rates up to 10-15 lpm.
  • Patient should wear a standard procedure mask over the nasal cannula to limit droplet spread.
  • A trial of lateral positioning or self-proning can occur.
  • If the target SpO2 of 92-96% is not achieved with nasal cannula up to 15 lpm, escalation to a non-rebreathing face mask (NRM) should be considered. 

 O2 by simple, venturi, or non-rebreathing face mask at < 15 lpm

  • Filtered non-rebreathing masks can be considered, as they may offer some additional staff protection due to viral filters over the expiratory ports.
  • Flow rates of supplemental oxygen should be limited to the least needed to achieve the target oxygen goal (e.g., SpO2 92-96%).
  • A trial of lateral position or self-proning can occur.

Regardless of device (i.e., nasal prongs, design-specific higher flow nasal cannula, simple, venturi, or non-rebreathing face mask), total flow rates < 15 lpm are NOT considered aerosol-generating. Therefore, negative pressure AIIR is not required. Staff should be protected by droplet/contact PPE.

IV.   Early tracheal intubation (1)

Indications

Significant hypoxemia refractory to non-rebreathing mask at flows < 15 lpm along with one or more of:

Indications

Significant hypoxemia refractory to non-rebreathing mask at flows < 15 lpm along with one or more of:

  1. Clinical signs of the patient tiring:
  • Dyspnea
  • Tachypnea with RR > 30-35 (adult)
  • Tachycardia
  • Agitation
  • Accessory muscle use
  • Paradoxical chest/abdomen movement
  1. Standard indications (e.g., failure to protect airway, hemodynamic instability)

Continuous positive airway pressure or high-flow nasal oxygen (1)

  • HFNO includes  Airvo™; Optiflow™; Vapotherm™, typically with humidified oxygen delivered at flow rates of 40-70 lpm.
  • CPAP/HFNO should be considered potentially aerosol-generating and ideally used in a negative pressure AIIR.
  • To reduce aerosolization potential, consider starting with the least supporting pressure (e.g., CPAP 8-10 cm H20) or for HFNO using FiO2 1.0 and reducing  flow to achieve adequate SpO2 (e.g., 92-96%).
  • Full airborne/droplet/contact PPE.
  • A trial of CPAP/HFNO  in the prone position can be considered in the cooperative awake, spontaneously breathing patient. 
  • If CPAP/HFNO is used, the patient should be closely monitored for deterioration, and if not responding favourably within a 30-60 minute trial period, should proceed to tracheal intubation.

 

Bi-level positive airway pressure (1)

  • BiPAP is not generally recommended for support of COVID-19 patients in hypoxemic respiratory failure.

Questions? Comments? Does this need to be updated? Do you have valuable points to add ? Please email ask.reakt@ubc.ca.

References

  1. Kovas G, Law, JA, Witter T.  Airway Management Guidelines for Patients with Known or Suspected COVID-19 Infection Version 3.7 [Internet]. AIME Airway. 2020 April 28 [cited 2020 May 4]; Available from:  https://aimeairway.ca/announcement/120/airway-management-guidelines-for-patients-with-known-or-suspected-covid-19-infection-version-3-7
  2. Alhazzani W, Møller MH, Arabi YM, Loeb M, Gong MN, Fan, E, et al. Surviving Sepsis Campaign: Guidelines on the Management of Critically Ill Adults with Coronavirus Disease 2019 (COVID-19). Intensive Care Medicine [Internet]. 2020 March 28 [cited 2020 April 13]; Available from: https://link.springer.com/article/10.1007%2Fs00134-020-06022-5

Disclaimer

The above is intended to serve as a rapidly-created, accessible source of information curated by medical students and healthcare professionals. It is for educational purposes only and is not a complete reference resource. It is not professional medical advice, and is not a substitute for the discretion, judgment, and duties of healthcare professionals. You are solely responsible for evaluating the information above.