Highlights
Early intravenous vitamin C, given for 96 hours after shockable out-of-hospital cardiac arrest, did not reduce post-cardiac arrest organ dysfunction.
The highest dose tested, 10 g daily, was associated with less improvement in the R-SOFA score and signals of worse troponin release, renal function, and neurological outcomes.
These results do not support routine high-dose vitamin C as a neuroprotective or organ-protective therapy after cardiac arrest.
The VITaCCA trial is an important reminder that biologic plausibility and antioxidant theory do not guarantee clinical benefit in critically ill patients.
Background: Why Vitamin C Was Considered
Out-of-hospital cardiac arrest remains one of the most devastating emergencies in modern medicine. Even when return of spontaneous circulation is achieved, many patients develop post-cardiac arrest syndrome, a complex state driven by global ischemia-reperfusion injury, inflammatory activation, vasoplegia, myocardial dysfunction, cerebral injury, and multi-organ failure. Despite progress in targeted temperature management and improvements in intensive care, there is still no broadly effective pharmacologic therapy that reliably improves neurological recovery or prevents organ dysfunction in this setting.
Vitamin C has attracted attention because of its pleiotropic biological effects. It acts as an antioxidant, may modulate endothelial function, and has been hypothesized to support catecholamine synthesis and improve vascular responsiveness. In critical care literature, these mechanisms have been discussed in the context of sepsis, vasopressor dependence, and shock. That rationale made vitamin C an appealing candidate for post-cardiac arrest care, where oxidative stress and inflammatory injury are prominent early after resuscitation.
However, mechanistic plausibility is not the same as clinical efficacy. The VITaCCA trial directly tested whether early intravenous vitamin C could attenuate organ dysfunction after resuscitated out-of-hospital cardiac arrest.
Study Design
VITaCCA was a double-blind, multicenter, phase 2 randomized clinical trial. It enrolled comatose adults resuscitated from shockable out-of-hospital cardiac arrest. Patients were assigned to receive intravenous placebo, supplementary-dose vitamin C at 3 g, or supraphysiological-dose vitamin C at 10 g daily for 96 hours.
The primary endpoint was the 96-hour change in the resuscitation-sequential organ failure assessment, or R-SOFA, score. This is a cardiac arrest-adapted organ dysfunction metric designed to capture the severity and evolution of post-resuscitation organ failure. Secondary endpoints included neurological outcome, myocardial injury, vasopressor-free days, ventilator-free days, renal function, ICU-acquired weakness, delirium, length of ICU and hospital stay, and mortality at 28 and 180 days.
From a trial-design perspective, several features strengthen the study: randomized allocation, double blinding, multicenter enrollment, and a placebo-controlled comparator. At the same time, this was a phase 2 trial focused on physiologic and clinical signals rather than definitive mortality benefit, so its findings should be interpreted as hypothesis-testing rather than practice-changing on their own.
Key Findings
A total of 273 patients were included in the primary analysis: 93 received placebo, 91 received 3 g vitamin C, and 89 received 10 g vitamin C.
At 96 hours, the mean change in R-SOFA score was -3.2 (SD 5.7) in the placebo group, -2.3 (SD 7.4) in the 3 g group, and -0.8 (SD 7.6) in the 10 g group. The overall between-group difference was statistically significant (p = 0.04).
The most important signal emerged in the 10 g group. Compared with placebo, 10 g vitamin C resulted in 2.5 points less improvement in R-SOFA score, with a 95% confidence interval of 0.5 to 4.5 and p = 0.01. Compared with the 3 g group, the 10 g group had 1.6 points less improvement, but this comparison was not statistically significant (95% CI -0.4 to 3.6; p = 0.12).
In other words, the higher dose did not merely fail to help; it appeared to correlate with worse recovery in a key organ dysfunction endpoint. The trial’s abstract also reports that 10 g vitamin C led to higher troponin T release, worse renal function, and worse neurological outcomes. These are clinically meaningful concerns because they point toward possible harm in organs most relevant to post-cardiac arrest prognosis.
The finding of increased troponin T release suggests greater myocardial injury or at least a biomarker pattern consistent with worse cardiac recovery. Deterioration in renal function is particularly important because post-arrest patients are already vulnerable to acute kidney injury from ischemia-reperfusion, hemodynamic instability, and exposure to nephrotoxic interventions. Worse neurological outcomes are perhaps the most consequential signal, since neurological recovery is the outcome that matters most to patients and families after successful resuscitation.
Notably, the abstract does not describe a clear clinical advantage for the 3 g dose over placebo. While the lower dose did not show the same negative signal as 10 g, it also did not convincingly improve organ dysfunction. This dose-response pattern argues against a simple “more is better” interpretation and raises the possibility that vitamin C at high concentrations may not behave as expected in this pathophysiologic context.
Clinical Interpretation
The VITaCCA trial is notable because it challenges an intervention that seemed attractive on theoretical grounds. Vitamin C is inexpensive, widely available, and biologically active. In many critical care discussions, such attributes can make a therapy seem low-risk and potentially high-yield. This study shows why randomized evidence remains essential.
There are several plausible explanations for why high-dose vitamin C may have failed or even appeared harmful. First, antioxidant strategies are highly context-dependent. Reactive oxygen species are not exclusively damaging; they also participate in cell signaling and host defense. Over-suppression of redox pathways could theoretically blunt adaptive responses during recovery. Second, the timing and dose may matter. A therapy beneficial in one critical illness phenotype may be ineffective or harmful in another. Third, biomarkers and organ scores after cardiac arrest are influenced by many concurrent interventions, making it difficult for a single agent to overcome the overall burden of injury.
Another important consideration is whether the observed harm reflects direct toxicity, interaction with underlying physiology, or chance findings from a phase 2 trial. The abstract alone does not establish a mechanistic cause. Yet the consistency of the negative signals in the 10 g group makes the result difficult to dismiss as random noise. At minimum, the study argues strongly against routine adoption of high-dose vitamin C in this population outside a trial.
Strengths and Limitations
The strengths of VITaCCA include its randomized, double-blind, multicenter design; its placebo comparator; and its clinically relevant population of comatose adults after shockable out-of-hospital cardiac arrest. The trial also assessed not only organ dysfunction but multiple downstream outcomes, including neurological and renal endpoints, which are highly relevant in post-resuscitation care.
Limitations should temper over-interpretation. This was a phase 2 trial, so it was not powered to provide definitive estimates of mortality benefit or harm. The results are focused on a specific subgroup: shockable out-of-hospital cardiac arrest. Generalizability to non-shockable rhythms, in-hospital arrests, or patients who are awake after resuscitation is uncertain. The abstract also does not provide enough detail to determine whether co-interventions, postarrest temperature management strategies, or baseline severity differed in ways that might influence outcomes. Finally, as with many critical care trials, surrogate endpoints such as R-SOFA are informative but do not substitute for robust patient-centered recovery measures.
How This Fits With Current Practice
At present, post-cardiac arrest care remains centered on high-quality critical care support: hemodynamic optimization, ventilation strategies, fever prevention or temperature management where appropriate, seizure monitoring, treatment of coronary causes when indicated, and careful neurological prognostication. VITaCCA does not add vitamin C to that core bundle. Instead, it suggests that clinicians should be cautious about extrapolating antioxidant strategies from other critical illness syndromes into cardiac arrest care.
The findings also align with a broader trend in critical care research: interventions that improve laboratory markers or seem mechanistically elegant may fail in rigorously controlled trials. For clinicians, that means the threshold for routine use should remain high, especially when the primary concern is meaningful neurological recovery.
Conclusion
VITaCCA provides the strongest randomized evidence to date that early intravenous vitamin C is not a beneficial adjunct after shockable out-of-hospital cardiac arrest. The 3 g dose did not clearly improve recovery, and the 10 g dose was associated with worse organ dysfunction and concerning signals for myocardial, renal, and neurological outcomes. Until further evidence emerges, high-dose vitamin C should not be considered standard post-arrest therapy.
For researchers, the trial is valuable not only because it is negative, but because it sharpens the field’s understanding of what does not work. In post-cardiac arrest syndrome, the most promising therapies will likely need to be targeted, mechanism-based, and tested in trials powered for patient-centered outcomes rather than surrogate improvement alone.
Funding and Clinical Trial Registration
Trial registration: NCT03509662.
The abstract provided does not specify the funding source. Readers should consult the full publication for detailed sponsor and support information.
References
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Sandroni C, Cronberg T, Sekhon M, et al. Prognostication in comatose survivors of cardiac arrest: an advisory statement from the Neurocritical Care Society and European Society of Intensive Care Medicine. Intensive Care Med. 2023.