I’m not convinced that this is really a distinction.

Here are the criteria:

+++

B. Critical Illness:
- Diagnosed with COVID-19 by standard RT-PCR assay or equivalent testing within 5 days of screening
AND
Evidence of critical illness, defined by at least 1 of the following:
- Respiratory failure defined based on resource utilization requiring at least 1 of the following: Endotracheal intubation and mechanical ventilation, oxygen delivered by high-flow nasal cannula, noninvasive positive pressure ventilation, ECMO, or clinical diagnosis of respiratory failure (in setting of resource limitation)
OR
- Shock (defined by SBP < 90 mm Hg, or Diastolic BP < 60 mm Hg or requiring vasopressors)
OR
-Multiple organ dysfunction/failure

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Unless patients can go into shock or suffer multiple organ failure without first suffering respiratory failure, then most (if not all) are likely to be ventilated.

Is there a distinction between “ventilated” and “mechanically ventilated”?

I just don’t see this being a significant “subset”.

But I’m not a doctor.