Vitamin C benefits ICU patients, reduces duration of mechanical ventilation
Delhi: Critically ill patients may benefit from the administration of vitamin C, a recent meta-analysis in the Journal of Intensive Care has suggested. According to the study, vitamin C shortened the duration of mechanical ventilation, but the effect was dependent on the severity of illness.
Vitamin C has shown to have various biochemical effects. In randomized trials, vitamin C has improved endothelial function, lowered blood pressure, increased left ventricular ejection fraction, decreased the incidence of atrial fibrillation, decreased bronchoconstriction, prevented pain, shortened the duration of colds, and decreased the incidence of colds in physically stressed people. Also, it was found to be beneficial against pneumonia. A previous meta-analysis of 12 controlled trials found that vitamin C reduced ICU stay on average by 8%.
Critical care patients often have very low vitamin C plasma levels. In healthy people, 0.1 grams per day of vitamin C is usually sufficient to maintain a normal plasma level. However, much higher doses, in the order of grams per day, are needed for critically ill patients to increase their plasma vitamin C levels to within the normal range. Therefore, high vitamin C doses may be needed to compensate for the increased metabolism in critically ill patients.
Elizabeth Chalker from University of Sydney, Sydney, Australia and Harri Hemilä from the University of Helsinki, Finland analyzed modification of the vitamin C effect on ventilation time, by the control group ventilation time (which we used as a proxy for severity of disease in the patients of each trial).
The researchers searched the online databases and included RCTs in which the administration of vitamin C was the only difference between the study groups. All doses and all durations of vitamin C administration were included. They identified nine potentially eligible trials, eight of which were included in the meta-analysis. Results of the eight trials were pooled including a total of 685 patients.
Key findings of the study include:
- Vitamin C shortened the length of mechanical ventilation on average by 14%.
- There was significant heterogeneity in the effect of vitamin C between the trials.
- Heterogeneity was fully explained by the ventilation time in the untreated control group.
- Vitamin C was most beneficial for patients with the longest ventilation, corresponding to the most severely ill patients.
- In five trials including 471 patients requiring ventilation for over 10 h, a dosage of 1–6 g/day of vitamin C shortened ventilation time on average by 25%.
"Vitamin C is a safe, low-cost essential nutrient. Given the strong evidence of benefit for more severely ill critical care patients along with the evidence of very low vitamin C levels in such patients, ICU patients may benefit from the administration of vitamin C. Further studies are needed to determine optimal protocols for its administration. Future trials should directly compare different dosage levels," says Dr. Hemilä.
The study, "Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis," is published in the Journal of Intensive Care.
