Vitamin C as a panacea has been an especially persistent philosophy. Cocktails along with Thiamine and Hydrocortisone are being investigated (and hyped) for sepsis, but there is no robust evidence to support the practice at this point.
This systematic review and meta-analysis of a mixed critically ill population finds no significant effect on acute kidney injury, survival, length of ICU or hospital stay. In cardiac surgery, beneficial effects on postoperative atrial fibrillation, ICU or hospital length of stay remain unclear.
Clearly further studies are needed before Vitamin C alone or as part of a cocktail can be recommended for critically ill patients.