Background: Vitamin C is a potent anti-oxidant essential for human health. Among critically ill patients with sepsis, there is a high incidence of vitamin C deficiency and vitamin C repletion has been associated with improved outcomes. The post-cardiac arrest syndrome shares a number of similarities to sepsis, however vitamin C levels in the post-arrest population have been incompletely characterized. In this study, we assessed vitamin C levels in a post-arrest population.
Methods: This was a retrospective observational study conducted at a tertiary care center. A convenience sample of post- arrest, sepsis, and healthy control patients was selected from previously completed studies for whom there were sufficient stored blood samples. Patients were enrolled between 2011-2016. All arrests were out-of-hospital. Vitamin C levels were measured from samples obtained within 6-hours of emergency department admission. The cardiac arrest patients additionally had vitamin C levels measured between 24-36 hours. Serum vitamin C levels were assessed using the Abcam ascorbic acid assay kit (ab65346). Median vitamin C levels were compared between groups using the Mann-Whitney U test and changes in vitamin C levels between time points in cardiac arrest patients were assessed using the Wilcoxon signed-rank test.
Results: Overall there were 25 patients in each of the post-arrest, sepsis, and healthy control groups (75 patients in total). Baseline levels of vitamin C were significantly lower in the sepsis group than in the control group (0.28mg/dL [0.11-0.62] vs. 0.91mg/dL [0.48-1.54], p=0.01) and lower in the cardiac arrest group than in the control group (0.33mg/dL [0.04-0.83] vs. 0.91mg/dL [0.48-1.54], p<0.01). There was no significant difference in vitamin C levels between the cardiac arrest and sepsis patients (p=0.78). A total of 11 cardiac arrest patients had samples available at the later time-point. The median vitamin C level among those patients was 0.08mg/dL (0.01-0.4), and was significantly lower than the baseline level (p=0.03).
Conclusion: In this cohort, serum vitamin C levels were lower in post arrest patients as compared to controls and were similar to levels in patients with sepsis. Vitamin C levels fell over the first day after hospitalization. This data suggests a role for future studies of vitamin C supplementation following cardiac arrest.