COVID-19: Respiratory treatment in critical care – current recommendations

23.03.2020
Author: Munir Karjaghli, Reviewer: Bernhard Schmitt, Matthias Himmelstoss, Jean-Michel Arnal
Last change: 15.06.2020, Revision 01 (v2), Mechanical ventilation guidelines - phenotypes A and B

In this article we outline the current recommendations for the respiratory treatment of COVID-19 patients drawn from recent literature and guidelines issued by various organizations worldwide. They reflect the status as at the date of last change shown here.

Choices regarding supplemental oxygen delivery and providing invasive respiratory support are crucial, and may impact outcomes as well as the saturation of critical care beds. The following action is essential:

  • Ensure airborne protection for every phase/step in critical care settings (wherever possible)
  • Anticipate needs, maximize first-pass success

SpO2

Target SpO2 92%–95%, higher for emergency patients. Use supplemental oxygen therapy at 5 l/min and higher. Hygiene precautions are essential: HFOT (High Flow Oxygen Therapy) and leaking NIV (noninvasive ventilation) interfaces may generate contaminated aerosols.

Caution with HFOT and NIV!

Before deciding to apply noninvasive therapies such as HFOT or NIV, consider their benefits versus the risk of airborne diffusion. These therapies may result in the widespread dispersion of exhaled air and infectious aerosols.

Known high failure rates in COVID-19 patients may be an additional argument against treating them with noninvasive therapies. Use HFOT and NIV in selected patients only, and closely monitor the patient situation for deterioration. Patients receiving a NIV trial should be in a monitored setting and cared for by experienced staff capable of endotracheal intubation, in case the patient deteriorates acutely or does not improve after about one hour. Patients with hemodynamic instability, multi-organ failure, or an abnormal mental status should not receive NIV.

Intubation

When deciding whether to perform an endotracheal intubation:

  • Adopt Early Warning Scores for intubation/quod vitam prognosis (consider DNR cases)
  • Identify an isolated room (negative pressure environment if possible)

It is preferable to perform intubation as an elective procedure, rather than waiting until it is an emergency (greater patient risk).

If the decision is made to inubate, ensure the minimum number of team members:

  • The most expert team member should perform the intubation and advanced airway control/ventilation (wearing PPE)
  • Expert assistant on protocols and devices (doctor/nurse wearing PPE)
  • Second doctor wearing PPE if complex maneuver/difficult airway is expected/planned
  • Doctor available wearing PPE outside the room
  • Observer putting on / taking off PPE outside the room 

Additional considerations for intubation:

  • Consider video laryngoscopy to ensure the highest possible level of hygiene and self-protection.
  • Ensure the duration of pre-oxygenation is sufficient before intubating ARDS patients (5 min with 100% Oxygen, using a face mask with reservoir bag, bag-valve mask, or NIV).
  • Continuous waveform capnography should be used for every tracheal intubation and in all patients dependent on mechanical ventilation unless this is impossible for any reason.

Before applying mechanical ventilation, consider the following:

  • Bacterial/viral filter on every oxygenation interface (face mask, circuit, endotracheal tube, supraglottic airway devices, introducer, airway exchange catheters, ventilator inspiratory and expiratory outlet)
  • Airway cart ready (disposable devices preferable)
  • Suction: Closed system prepared with tube extension

Mechanical ventilation

I.   Carefully identify those patients in need of Mechanical Ventilation (MV).

II.  Ensure correct phenotyping of patients according to the following criteria (proposed by Gattinoni et al.).

Type H phenotype Type L phenotype
High elastance (low compliance) Low elastance
High right-to-left shunt Low ventilation-to-perfusion (V/Q) ratio
High lung weight Low lung weight
High lung recruitability Low lung recruitability


*The P/V Tool® Pro can be used to phenotype patients and assess lung recruitability.  

III.  Select the ventilation strategy according to the phenotype. 

A.  Type H phenotype:

Apply mechanical ventilation according to the current recommendations for treatment of ARDS patients: 

  1. Tidal volume: 4 - 6 ml/kg predicted body weight
     
  2. Pplat < 30 cmH2O
     
  3. Maintain the driving pressure (Pplat-PEEP) as low as possible (< 14 cmH2O)
     
  4. Permissive hypercapnia
     
  5. Higher PEEP (PEEP ≤ 15cmH2O) settings may be beneficial in patients with moderate-to-severe ARDS
     
  6. Recruitment maneuvers (RMs) are not routinely recommended in COVID-19 patients
     
  7. RM and higher PEEP >15 can be beneficial in patients with the typical CT pattern of moderate-to-severe ARDS, with alveolar edema, obesity, decrease in chest wall compliance and high potential for lung recruitment
     
  8. Prone positioning should be used only as a rescue maneuver 
     
  9. Avoid unnecessary disconnections of breathing circuits (if needed, put ventilator on standby / clamp endotracheal tube before disconnection) to ensure airborne protection and maintain PEEP
     
  10. Use weaning protocols to reduce the duration of invasive mechanical ventilation, considering the following points:
  • Weaning should be undertaken with caution
  • Make transitions carefully and avoid abrupt changes 
  • Perform spontaneous trials only at the very end of the weaning process
  • Strong spontaneous efforts raise O2 demand, increase edema, and promote P-SILI (patient self-induced lung injury)
  1. Follow a conservative fluid management strategy for ARDS patients without tissue hypoperfusion
     
  2. Closely monitor the cardiac function of the patient

B.    Type L phenotype:

  1. For nonintubated hypoxic patients who are not yet breathless, the first step to reverse hypoxemia is through an increase in FiO2
     
  2. For patients with dyspnea, several noninvasive options are available including:
  • High Flow Nasal Cannula (HFNC)
  • Continuous Positive Airway Pressure (CPAP)
  • Noninvasive Ventilation (NIV)

Ensure close monitoring if noninvasive ventilation is used, as it may be associated with high failure rates and delayed intubation in a disease that typically lasts a few weeks.
 

  1. Consider measurement (or estimation) of the work of breathing, by means of:
  • Inspiratory esophageal pressure swings
  • Surrogate measures of work of breathing, such as the swings of central venous pressure, or clinical detection of excessive inspiratory effort
  • P0.1 and P occlusion (if the patient is intubated) 
     
  1.  If inspiratory pleural pressures swings are greater than 15 cmH2O, the risk of lung injury increases and intubation should therefore be performed as soon as possible
     
  2. Early intubation may avert the transition to the Type H phenotype
     
  3. Adjust VT to 7-8ml/kg and RR to achieve an acceptable gas exchange. The high compliance results in tolerable strain without the risk of VILI 
     
  4. Prone positioning should be used only as a rescue maneuver
     
  5. PEEP should be reduced to 8-10 cmH2O, given that the recruitability is low and the risk of hemodynamic failure increases at higher levels 

References

  1. Marini JJ, Gattinoni L. Management of COVID-19 Respiratory Distress. JAMA. Published online April 24, 2020. doi:10.1001/jama.2020.6825
  2. Papazian, Laurent, et al. Formal guidelines: management of acute respiratory distress syndrome. Annals of intensive care 9.1 (2019): 69.
  3. Kluge, S., Janssens, U., Welte, T. et al. Empfehlungen zur intensivmedizinischen Therapie von Patienten mit COVID-19. Med Klin Intensivmed Notfmed (2020). https://doi.org/10.1007/s00063-020-00674-3).
  4. Amato, Marcelo BP, et al. Driving pressure and survival in the acute respiratory distress syndrome. New England Journal of Medicine 372.8 (2015): 747-755.
  5. World Health Organisation: Clinical management of severe acute respiratory infection (SARI) when COVID-19 disease is suspected: Interim guidance V 1.2 (March 2020)
  6. WHO guidelines: https://www.who.int/emergencies/diseases/novel-coronavirus-2019/technical-guidance
  7. COVID-19 Airway Management Rev 1.1, SIAARTI, M. Sorbello, I. Di Giacinto, F. Bressan, R. Cataldo, G. Cortese, C. Esposito, S. Falcetta, G. Merli , F. Petrini on behalf of SIAARTI Airway Management Research Group (March 2020)
  8. Robba C, Battaglini D, Ball L, et al. Distinct phenotypes require distinct respiratory management strategies in severe COVID-19. Respiratory Physiology & Neurobiology. 2020 May;279:103455. DOI: 10.1016/j.resp.2020.103455.
  9. Cook TM, El-Boghdadly K, McGuire B, McNarry AF, Patel A, Higgs A. Consensus guidelines for managing the airway in patients with COVID-19: Guidelines from the Difficult Airway Society, the Association of Anaesthetists the Intensive Care Society, the Faculty of Intensive Care Medicine and the Royal College of Anaesthetists. Anaesthesia. 2020;75(6):785-799. doi:10.1111/anae.15054

For additional information on COVID-19:

  1. ESICM information: https://www.esicm.org/resources/coronavirus-public-health-emergency/
  2. Current evidence about COVID-19: https://jamanetwork.com/journals/jama/pages/coronavirus-alert
  3. Centers for Disease Control and Prevention, CDC: https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guidance-management-patients.html

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