- active use of nac - known nac allergy - in the opinion of the treating team, progression of death is imminent and inevitable within the next 24 hour, irrespective of provision treatment - all patients enrolled in any other investigational drug studies in covid-19.

- active use of nac - known nac allergy - in the opinion of the treating team, progression of death is imminent and inevitable within the next 24 hour, irrespective of provision treatment - all patients enrolled in any other investigational drug studies in covid-19.