Category: Critical Care
Keywords: ARDS COVID19 (PubMed Search)
This week we anticipate treating more COVID19 cases as they progress to ARDS. The World Health Organization issued guidelines on 3/13/20 for treating Severe Acute Respiratory Infection (SARI) due to COVID19.
How to identify ARDS?
No different than before COVID. Order a CXR, ABG, and perform bedside ultrasound evaluation of cardiac function and volume status. If there are bilateral opacifications you cannot explain entirely with volume overload, nodules, or lobar collapse, AND if the ratio of PaO2/FiO2 is < 300 (mild), < 200 (moderate), or < 100 (severe), then treat for ARDS.
***While you are waiting for your blood gas, SpO2/FiO2 <315 suggests ARDS.
What is the oxygen goal?
During resuscitation: > 93%
Once stabilized: > 89%
What is the expected clinical course?
Patients experience RAPID deterioration to respiratory failure. You should expect to intubate. This should be performed with N95 protection and should be done by the person with greatest first pass success.
Be CONSERVATIVE with fluids. Do not give a 30mL/kg bolus. Give 250-500mL bolus and re-evaluate. Excess fluid results in prolonged hypoxia and mechanical ventilation.
Should empiric treatments change?
No. Co-infection with influenza, bacterial pneumonia, and all other pathogens is possible, so you should continue to cover all suspected pathogens and de-escalate as microbiology labs result.
Should ventilator settings change?
No. Use lung protective volumes and permissive hypercapnia. The volume is based on the patient's height, not weight. A quick way to do this? Measure the height in cm. Subtract 100 for a man and subtract 110 for a woman and this is the ideal body weight. Provide 6mL/kg of tidal volume with a goal plateau pressure < 30. Use the high PEEP strategy from the ARDSnet trial and even consider clamping the ET tube when transitioning from machine to bag for transport in order to preserve PEEP.
Do patients benefit from proning?
Yes. 12-16 hours/day for severe ARDS. Not true in pregnancy as a whole, though early pregnancy may still benefit.
Is ECMO beneficial in refractory cases?
Unknown. In the case of MERS-CoV, ECMO reduced mortality.
Are corrticosteroids useful?
No. Do not administer steroids routinely to these patients. You may give steroids where indicated, including cases of refractory shock following pressors.
Clinical Management of Severe Acute Respiratory Infection (SARI) when COVID 19 disease is suspected: interim guidance, 13 March 2020
Arabi YM, Arifi AA, Balkhy HH, Najm H, Aldawood AS, Ghabashi A et al. Clinical course and outcomes of critically ill patients with Middle East respiratory syndrome coronavirus infection. Ann Intern Med. 2014;160(6):38997.