Efficacy of Megadose Vitamin C in Severe and Critical Ill COVID-19 Patients.

The main aim is to determine whether vitamin C can reduce 28-day all-cause mortality or persistent organ dysfunction compared with placebo in patients with severe and critical ill COVID-19 patients.Participants will randomly receive HIVC or placebo for 4 days once enrolled. The primary outcome is a composite of death or persistent organ dysfunction (defined as dependency on vasopressors, mechanical ventilation, or CRRT) at day 28 after randomization.

Inclusion Criteria:Adults (age 18 years or older).Diagnosed with COVID-19 according to the Diagnosis and Clinical Management of COVID-19. (trial version 10).severe and critical ill patients with COVID-19.Patients who voluntarily participate in the study and sign the informed consent form.Exclusion Criteria:Patients with a history of allergy to VC.Pregnant or lactating women.Patients with end-stage malignant tumour.Patients with an expected survival duration of less than 24 hours.Patients with cerebral hernia and severe craniocerebral injury.Patients with diabetes.Patients with a previous history of G-6-PD deficiency.