Harm of IV High-Dose Vitamin C Therapy in Adult Patients: A Scoping Review

Hemolysis attributed to high dose vitamin C: Two case reports

BACKGROUND

High-dose vitamin C treatment (HVCT) can reduce the adverse effect of chemotherapy and enhance the effect of antitumor therapy, which has been considered one of the safest alternative treatments. However, the severity of its adverse effects may have been underestimated. The most serious adverse effect is hemolysis, which may result in acute kidney injury or death. Although glucose-6-phosphate dehydrogenase (G6PD) deficiency is considered to be the main cause, the probability and pathological mechanism are not completely understood, leading to a lack of effective and standardized treatment methods.

CASE SUMMARY

Two patients with colorectal cancer developed hemolytic anemia after using 1 g/kg HVCT. In contrast to previous cases, the lowest hemoglobin level in the two cases was < 50 g/L, which was lower than previously reported. This may be because Case 1 had chronic hepatitis B for many years, which caused abnormal liver reserve function, and Case 2 had grade II bone marrow suppression. Both patients improved and were discharged after blood replacement therapy. Our cases had the most severe degree of hemolysis but the best prognosis, suggesting that our treatment may be helpful for rescue of drug-induced hemolysis. This is the first review of the literature on hemolysis caused by HVCT, and we found that all patients with G6PD deficiency developed hemolysis after HVCT.

CONCLUSION

G6PD deficiency should be considered as a contraindication to HVCT, and it is not recommended for patients with bone marrow suppression, moderate-to-severe anemia, hematopoietic abnormalities, or abnormal liver and kidney function. Early blood purification and steroid therapy may avoid acute kidney injury or death caused by HVCT-related hemolytic anemia.

Vitamin C for all?

PURPOSE OF REVIEW

Vitamin C can be a potential adjunctive treatment option for critically ill individuals due to its pleiotropic effects as electron donor in many enzymatic reactions throughout the body. Recently, several important randomized controlled trials (RCTs) investigating vitamin C in critically ill patients have been published.

RECENT FINDINGS

Two recent large RCTs administering high-dose vitamin C to patients with sepsis and COVID-19 showed signs of harm. Though performed at high standard, these trials had several limitations. Recent studies in cardiac surgery and burns showed decreased cardiac enzymes and improved clinical outcomes after cardiac surgery, and decreased fluid requirements, reduced wound healing time and in-hospital mortality after burns. Vitamin C may hold benefit in the management of other ischemia/reperfusion injury populations, including postcardiac arrest patients and after solid organ transplantation. Currently, covering basal vitamin C requirements during critical illness is recommended, though the exact dose remains to be determined.

SUMMARY

Future work should address optimal vitamin C timing, since early versus late drug administration are likely distinct, and duration of therapy, where withdrawal-induced injury is possible. Additionally accurate assessment of body stores with determination of individual vitamin requirements is crucial to ascertain patient and subgroups most likely to benefit from vitamin C.

Role of vitamin C in treatment of community-acquired pneumonia in adult patients requiring hospitalisation: a systematic review protocol

INTRODUCTION

Community-acquired pneumonia (CAP) is a leading cause of hospitalisation and is associated with a high mortality. Vitamin C is a powerful antioxidant and has been used in treatment of infections; however, its role as an adjunctive treatment in CAP is unclear. This review aims to assess the efficacy and safety of vitamin C in adults who require hospitalisation for CAP.

METHODS AND ANALYSES

Searches will be conducted from inception to November 2023 on Ovid MEDLINE Daily and MEDLINE, Embase CINAHL, the Cochrane Central Register of Controlled Trials, Scopus, Web of Science and ClinicalTrials.gov databases with the aid of a medical librarian. We will include data from randomised controlled trials reporting vitamin C supplementation in patients with CAP requiring hospitalisation. Two independent reviewers will select studies, extract data and will assess the risk of bias by use of the Risk of Bias tool. The overall certainty of evidence will be assessed by use of the Grading of Recommendations Assessment, Development and Evaluation framework. Random-effects meta-analyses will be conducted, and effect measures will be reported as relative risks with 95% CIs.

ETHICS AND DISSEMINATION

No previous ethical approval is required for this review. The findings of this review will be submitted to a scientific journal and presented at an international medical conference.

PROSPERO REGISTRATION NUMBER

483860.

Resuscitation With Vitamin C, Hydrocortisone, and Thiamin in Children With Septic Shock: A Multicenter Randomized Pilot Study

OBJECTIVES

Adjunctive therapy with vitamin C, hydrocortisone, and thiamin has been evaluated in adults, but randomized controlled trial (RCT) data in children are lacking. We aimed to test the feasibility of vitamin C, hydrocortisone, and thiamin in PICU patients with septic shock; and to explore whether the intervention is associated with increased survival free of organ dysfunction.

DESIGN

Open-label parallel, pilot RCT multicenter study. The primary endpoint was feasibility. Clinical endpoints included survival free of organ dysfunction censored at 28 days and nine secondary outcomes, shock reversal, and two proxy measures of intervention efficacy.

SETTING

Six PICUs in Australia and New Zealand.

PATIENTS

Children of age between 28 days and 18 years requiring vasoactive drugs for septic shock between August 2019 and March 2021.

INTERVENTIONS

Patients were assigned 1:1 to receive 1 mg/kg hydrocortisone every 6 hours (q6h), 30 mg/kg ascorbic acid q6h, and 4 mg/kg thiamin every 12 hours (n = 27), or standard septic shock management (n = 33).

MEASUREMENTS AND MAIN RESULTS

Sixty of 77 (78%) eligible patients consented with 91% of approached parents providing consent. The median time from randomization to intervention was 44 (interquartile range [IQR] 29-120) min. Seventy of seventy-seven (28%) patients had received IV steroids before randomization. Median survival alive and free of organ dysfunction was 20.0 (0.0-26.0) days in the intervention and 21.0 (0.0-25.0) days in the standard care group. Median PICU length of stay was 5.3 (2.5-11.3) days in the intervention group versus 6.9 (3.0-11.5) days in the control group. Shock reversal occurred at a median of 35.2 (14.6-101.2) hours in the intervention group versus 47.3 (22.4-106.8) hours in the standard care group (median difference -12 hr; 95% CI, -56.8 to 32.7 hr).

CONCLUSIONS

In children requiring vasopressors for septic shock, a protocol comparing adjunctive treatment with high-dose vitamin C, hydrocortisone, and thiamin versus standard care was feasible. These findings assist in making modifications to the trial protocol to enable a better-designed larger RCT.

Mega-dose sodium ascorbate: a pilot, single-dose, physiological effect, double-blind, randomized, controlled trial

BACKGROUND

Mega-dose sodium ascorbate (NaAscorbate) appears beneficial in experimental sepsis. However, its physiological effects in patients with septic shock are unknown.

METHODS

We conducted a pilot, single-dose, double-blind, randomized controlled trial. We enrolled patients with septic shock within 24 h of diagnosis. We randomly assigned them to receive a single mega-dose of NaAscorbate (30 g over 1 h followed by 30 g over 5 h) or placebo (vehicle). The primary outcome was the total 24 h urine output (UO) from the beginning of the study treatment. Secondary outcomes included the time course of the progressive cumulative UO, vasopressor dose, and sequential organ failure assessment (SOFA) score.

RESULTS

We enrolled 30 patients (15 patients in each arm). The mean (95% confidence interval) total 24-h UO was 2056 (1520-2593) ml with placebo and 2948 (2181-3715) ml with NaAscorbate (mean difference 891.5, 95% confidence interval [- 2.1 to 1785.2], P = 0.051). Moreover, the progressive cumulative UO was greater over time on linear mixed modelling with NaAscorbate (P < 0.001). Vasopressor dose and SOFA score changes over time showed faster reductions with NaAscorbate (P < 0.001 and P = 0.042). The sodium level, however, increased more over time with NaAscorbate (P < 0.001). There was no statistical difference in other clinical outcomes.

CONCLUSION

In patients with septic shock, mega-dose NaAscorbate did not significantly increase cumulative 24-h UO. However, it induced a significantly greater increase in UO and a greater reduction in vasopressor dose and SOFA score over time. One episode of hypernatremia and one of hemolysis were observed in the NaAscorbate group. These findings support further cautious investigation of this novel intervention. Trial registration Australian New Zealand Clinical Trial Registry (ACTRN12620000651987), Date registered June/5/2020.

Intravenous vitamin injections: where is the evidence?

The body needs small daily quantities of vitamins and minerals, which are usually obtained from the diet. Intravenous vitamins are used for a few serious medical conditions (eg, malabsorption syndromes with severe vitamin depletion, Wernicke's encephalopathy or critical illness). Intravenous drips containing high doses of various vitamins and minerals (eg, the so-called 'Myers' cocktail') have been promoted in popular culture to 'reduce stress', 'increase energy' or 'boost immunity', with claims that the intravenous route allows faster absorption of vitamins into the bloodstream than if they are taken orally. There is a lack of high-quality evidence to suggest that high-dose vitamin infusions are necessary or offer any health benefit in the absence of a specific vitamin deficiency or medical condition. There may be harms from taking high (non-physiological) quantities of some vitamins and minerals. Licensed forms of injectable vitamins that are prescription-only medicines should not be advertised to the public and should only be supplied and administered by appropriately qualified healthcare professionals.

Intravenous vitamin C monotherapy in critically ill patients: a systematic review and meta-analysis of randomized controlled trials with trial sequential analysis

BACKGROUND

A recent landmark randomized controlled trial (RCT) in septic patients demonstrated an increased risk of death and persistent organ dysfunction with intravenous Vitamin C (IVVC) monotherapy, which represents a disparate result from previous systematic reviews and meta-analyses (SRMA). We performed an updated SRMA of IVVC monotherapy to summarize and explore heterogeneity across current trials and conduct trial sequential analysis (TSA) to guard against type-I or type-II statistical errors.

METHODS

RCTs evaluating IVVC in adult critically ill patients were included. Four databases were searched from inception to 22 June 2022 without language restrictions. The primary outcome was overall mortality. Random effect meta-analysis was performed to estimate the pooled risk ratio. TSA for mortality was performed using the DerSimonian-Laird random effect model, alpha 5%, beta 10%, and relative risk reduction (RRR) of 30%, 25%, and 20%.

RESULTS

We included 16 RCTs (n = 2130). IVVC monotherapy is associated with significant reduction in overall mortality [risk ratio (RR) 0.73, 95% confidence interval (CI) 0.60-0.89; p = 0.002; I² = 42%]. This finding is supported by TSA using RRR of 30% and 25%, and sensitivity analysis using fixed-effect meta-analysis. However, the certainty of our mortality finding was rated low using GRADE due to the serious risk of bias and inconsistency. In a priori subgroup analyses, we found no differences between single vs multicenter, higher (≥ 10,000 mg/day) vs lower dose and sepsis vs non-sepsis trials. Post-hoc, we found no differences in subgroup analysis of earlier (< 24 h) vs delayed treatment, longer (> 4 days) vs shorter treatment duration, and low vs other risk of bias studies. IVVC may have the greatest benefit in trials that enrolled patients above (i.e., > 37.5%; RR 0.65, 95% CI 0.54-0.79) vs below (i.e., ≤ 37.5%; RR 0.89, 95% CI 0.68-1.16) median control group mortality (test for subgroup differences: p = 0.06), and TSA supported this.

CONCLUSIONS

IVVC monotherapy may be associated with mortality benefits in critically ill patients, particularly in patients with a high risk of dying. Given the low certainty of evidence, this potentially life-saving therapy warrants further studies to identify the optimal timing, dosage, treatment duration, and patient population that will benefit most from IVVC monotherapy. PROSPERO Registration ID: CRD42022323880. Registered 7th May 2022.

Current role of high dose vitamin C in sepsis management: A concise review

Sepsis and septic shock are common diagnoses for patients requiring intensive care unit admission and associated with high morbidity and mortality. In addition to aggressive fluid resuscitation and antibiotic therapy, several other drugs have been tried as adjuvant therapies to reduce the inflammatory response and improve outcomes. Vitamin C has been shown to have several biological actions, including anti-inflammatory and immunomodulatory effects, which may prove beneficial in sepsis management. Initial trials showed improved patient outcomes when high dose vitamin C was used in combination with thiamine and hydrocortisone. These results, along with relative safety of high-dose (supra-physiological) vitamin C, encouraged physicians across the globe to add vitamin C as an adjuvant therapy in the management of sepsis. However, subsequent large-scale randomised control trials could not replicate these results, leaving the world divided regarding the role of vitamin C in sepsis management. Here, we discuss the rationale, safety profile, and the current clinical evidence for the use of high-dose vitamin C in the management of sepsis and septic shock.

Role of high dose vitamin C in management of hospitalised COVID-19 patients: A minireview

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as one of the most dreadful viruses the mankind has witnessed. It has caused world-wide havoc and wrecked human life. In our quest to find therapeutic options to counter this threat, several drugs have been tried, with varying success. Certain agents like corticosteroids, some anti-virals and immunosuppressive drugs have been found useful in improving clinical outcomes. Vitamin C, a water-soluble vitamin with good safety profile, has been tried to reduce progression and im-prove outcomes of patients with coronavirus disease 2019 (COVID-19). Because of its anti-oxidant and immunomodulatory properties, the role of vitamin C has expanded well beyond the management of scurvy and it is increasingly been employed in the treatment of critically ill patients with sepsis, septic shock, acute pancreatitis and even cancer. However, in spite of many case series, observational studies and even randomised control trials, the role of vitamin C remains ambiguous. In this review, we will be discussing the scientific rationale and the current clinical evidence for using high dose vitamin C in the management of COVID-19 patients.

Intravenous Ascorbic Acid and Lung Function in Severely IllCOVID-19 Patients

Current evidence suggests that ascorbic acid improves the host’s immune system and, therefore, may play a role in reducing the severity of infectious diseases. Coronavirus disease 2019 (COVID-19) is a potentially life-threatening viral infection that mainly infects the lungs. The objective of this review was to synthesize the existing findings from studies related to the effect of intravenous ascorbic acid on lung function in COVID-19 patients. For this review, PubMed, Cochrane, SCOPUS, EMBASE, Clinical Trial Registry, and Google Scholar databases were searched from December 2019 to May 2022. There was a total of six studies that investigated the large dose of ascorbic acid infusion intravenously on lung function in severely ill subjects with COVID-19. Out of six, three studies found that high-dose intravenous ascorbic acid improved lung function markers, and three studies found null results. Infusions of 12 g/d and 24 g/d of intravenous ascorbic acid had shown a significant improvement in lung function markers in two clinical trials. Studies that administered 8 g/d, 2 g/d, and 50 mg/kg/d of intravenous ascorbic acid found no influence on mechanical ventilation need and other lung function markers in critically ill subjects with COVID-19. Overall, the effect of intravenous ascorbic acid on the lung function of subjects with COVID yielded equivocal findings. More double-blinded, randomized, clinical studies with a larger sample size are required to confirm the effect of ascorbic acid in ameliorating the lung pathologies associated with COVID infection.

Parenteral Vitamin C in Patients with Severe Infection: A Systematic Review

BACKGROUND: Inflammation and oxidative damage caused by severe infections may be attenuated by vitamin C. METHODS: We conducted a systematic review of randomized controlled trials (RCTs) of parenteral vitamin C as combined therapy or monotherapy versus no parenteral vitamin C administered to adults hospitalized with severe infection. The primary outcome was mortality. We performed random-effects meta-analyses and assessed certainty in effect estimates. RESULTS: Of 1547 citations, 41 RCTs (n = 4915 patients) were eligible for inclusion. Low-certainty evidence suggested that vitamin C may reduce in-hospital mortality (21 RCTs, 2762 patients; risk ratio, 0.88 [95% confidence interval (CI), 0.73 to 1.06]), 30-day mortality (24 RCTs, 3436 patients; risk ratio, 0.83 [95% CI, 0.71 to 0.98]), and early mortality (before hospital discharge or 30 days; 34 RCTs, 4366 patients; risk ratio, 0.80 [95% CI, 0.68 to 0.93]). Effects were attenuated in sensitivity analyses limited to published blinded trials at low risk-of-bias (in-hospital mortality: risk ratio, 1.07 [95% CI, 0.92 to 1.24], moderate certainty; 30-day mortality: risk ratio, 0.88 [95% CI, 0.71 to 1.10], low certainty; and early mortality: risk ratio, 0.88 [95% CI, 0.73 to 1.06], low certainty). For 90-day mortality, all trials had low risk-of-bias; moderate-certainty evidence suggested harm (five RCTs, 1722 patients; risk ratio, 1.07 [95% CI, 0.94 to 1.21]). Moderate-certainty evidence suggested an increased risk of hypoglycemia (risk ratio, 1.20 [95% CI, 0.69 to 2.08]). Effects on other secondary outcomes were mixed and informed by low-certainty evidence. No credible subgroup effects were observed for mortality related to cointerventions (monotherapy vs. combined therapy), dose, or type of infection (Covid-19 vs. other). CONCLUSIONS: Overall, evidence from RCTs does not establish a survival benefit for vitamin C in patients with severe infection. (PROSPERO number, CRD42020209187.)

Reoccurring Episcleritis and the Role of Antioxidants

Episcleritis is an irritation of the episclera of our eyes. Episclera is a thin layer of tissue present between the conjunctiva and sclera. There are mainly four causes of episcleritis: an allergic response, autoimmune, vascular disease, or infections. The symptoms are redness, erythema, discomfort in the eyes, and clear discharge. It can sometimes be painful as well. In this case presentation, we will discuss the role of vitamin c in the prevention and reoccurrence of autoimmune episcleritis.

Effect of Vitamin C on Clinical Outcomes of Critically Ill Patients With COVID-19: An Observational Study and Subsequent Meta-Analysis

Background

Whether vitamin C provides any benefit when administered in critically ill patients, including those with coronavirus disease (COVID-19), is controversial. We endeavored to estimate the effect of administration of vitamin C on clinical outcomes of critically ill patients with COVID-19 by performing an observational study and subsequent meta-analysis.

Methods

Firstly, we conducted an observational study of critically ill patients with laboratory-confirmed COVID-19 who consecutively underwent invasive mechanical ventilation in an academic intensive care unit (ICU) during the second pandemic wave. We compared all-cause mortality of patients receiving vitamin C (“vitamin C” group) or not (“control” group) on top of standard-of-care. Subsequently, we systematically searched PubMed and CENTRAL for relevant studies, which reported on all-cause mortality (primary outcome) and/or morbidity of critically ill patients with COVID-19 receiving vitamin C or not treatment. Pooled risk ratio (RR) and 95% confidence intervals (CI) were calculated using a random effects model. The meta-analysis was registered with PROSPERO.

Results

In the observational study, baseline characteristics were comparable between the two groups. Mortality was 20.0% (2/10) in the vitamin C group vs. 47.6% (49/103; p = 0.11) in the control group. Subsequently, the meta-analysis included 11 studies (6 observational; five randomized controlled trials) enrolling 1,807 critically ill patients with COVID-19. Mortality of patients receiving vitamin C on top of standard-of-care was not lower than patients receiving standard-of-care alone (25.8 vs. 34.7%; RR 0.85, 95% CI 0.57–1.26; p = 0.42).

Conclusions

After combining results of our observational cohort with those of relevant studies into a meta-analysis of data from 1,807 patients, we found that administration vitamin C as opposed to standard-of-care alone might not be associated with lower of mortality among critically ill patients with COVID-19. Additional evidence is anticipated from relevant large randomized controlled trials which are currently underway.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021276655.

Vitamin C-induced Hemolysis: Meta-summary and Review of Literature

Vitamin C is increasingly being used, and even high doses are considered safe. However, complications including hemolysis have been reported. We performed a systematic search from PubMed, Science Direct, and Google Scholar databases from January 1975 till July 31, 2021. Search terms used were "Vitamin C" OR "ascorbic acid" AND "haemolysis" OR "haemolytic anaemia." Data regarding patient's demographics, outcomes and dose, duration, and form of vitamin C were extracted. Fourteen case reports matched the selected criteria, with age ranging from 3 weeks to 75 years with 78.6% being males. About 71.4% were diagnosed to have glucose-6-phosphate dehydrogenase (G6PD) deficiency but previous hemolysis was reported in only two patients, and 57.1% were prescribed vitamin C for nutritional supplementation. The dose ranged from 1 to 200 g/day with 57.1% receiving intravenous formulations. Half of these patients developed other complications including acute kidney injury (AKI), disseminated intravascular coagulation, oxalosis, and methemoglobinemia. About 78.6% developed complications within 3 days of starting vitamin C and only one death was reported. Vitamin C is generally a safe drug but it should be prescribed with caution and only when benefits outweigh the risks. Physicians should be aware of potential complications like severe hemolysis and AKI, especially when using high doses and in G6PD deficiency.

HOW TO CITE THIS ARTICLE

Juneja D, Jain R, Nasa P. Vitamin C-induced Hemolysis: Meta-summary and Review of Literature. Indian J Crit Care Med 2022;26(2):224-227.

Effect of adjunctive vitamin C, glucocorticoids, and vitamin B1 on longer-term mortality in adults with sepsis or septic shock: a systematic review and a component network meta-analysis

We aimed to compare the effects of vitamin C, glucocorticoids, vitamin B1, combinations of these drugs, and placebo or usual care on longer-term mortality in adults with sepsis or septic shock. MEDLINE, Embase, CENTRAL, ClinicalTrials.gov and WHO-ICTRP were searched. The final search was carried out on September 3rd, 2021. Multiple reviewers independently selected randomized controlled trials (RCTs) comparing very-high-dose vitamin C (≥ 12 g/day), high-dose vitamin C (< 12, ≥ 6 g/day), vitamin C (< 6 g/day), glucocorticoid (< 400 mg/day of hydrocortisone), vitamin B1, combinations of these drugs, and placebo/usual care. We performed random-effects network meta-analysis and, where applicable, a random-effects component network meta-analysis. We used the Confidence in Network Meta-Analysis framework to assess the degree of treatment effect certainty. The primary outcome was longer-term mortality (90-days to 1-year). Secondary outcomes were severity of organ dysfunction over 72 h, time to cessation of vasopressor therapy, and length of stay in intensive care unit (ICU). Forty-three RCTs (10,257 patients) were eligible. There were no significant differences in longer-term mortality between treatments and placebo/usual care or between treatments (10 RCTs, 7,096 patients, moderate to very-low-certainty). We did not find any evidence that vitamin C or B1 affect organ dysfunction or ICU length of stay. Adding glucocorticoid to other treatments shortened duration of vasopressor therapy (incremental mean difference, - 29.8 h [95% CI - 44.1 to - 15.5]) and ICU stay (incremental mean difference, - 1.3 days [95% CI - 2.2 to - 0.3]). Metabolic resuscitation with vitamin C, glucocorticoids, vitamin B1, or combinations of these drugs was not significantly associated with a decrease in longer-term mortality.

Administration of parenteral vitamin C in patients with severe infection: protocol for a systematic review and meta-analysis

Background

Severe infections are characterized by inflammation and oxidative damage. Ascorbic acid (vitamin C) administration may attenuate oxidative damage and, in turn, reduce vascular endothelial injury in pulmonary and systemic vasculature.

Objective

We aim to describe a protocol for a living systematic review that will evaluate the effectiveness and safety of parenteral vitamin C administration in adults with severe infections, including those with COVID-19.

Methods

We searched Ovid MEDLINE, Embase, CINAHL, the Centers for Disease Control and Prevention COVID-19 database, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from inception to March 30, 2021, for randomized controlled trials evaluating parenteral vitamin C versus no parenteral vitamin C in hospitalized adults with severe infection. Eligible studies will include at least 1 arm involving any dose of parenteral vitamin C alone or in combination with other cointerventions and at least 1 arm not involving parenteral vitamin C. The primary outcomes of interest will include in-hospital, 30-day, and 90-day mortality. Title and abstract screening, full-text screening, data extraction, and risk of bias evaluation via a modified Risk of Bias 2.0 tool will be conducted independently and in pairs. We will perform random effects modeling for meta-analyses, in which study weights will be generated by using the inverse variance method. We will assess certainty in effect estimates by using the Grading of Recommendations Assessment, Development and Evaluation methodology. Meta-analyses will be updated iteratively as new trial evidence becomes available.

Results

Among the 1386 citations identified as of March 30, 2021, a total of 17 eligible randomized controlled trials have been identified as of September 2021. We are in the process of updating the search strategy and associated data analyses.

Conclusions

The results will be of importance to critical care physicians and hospitalists who manage severe infection and COVID-19 in daily practice, and they may directly inform international clinical guidance. Although our systematic review will incorporate the most recent trial evidence, ongoing trials may change our confidence in the estimates of effects, thereby necessitating iterative updates in the form of a living review.

Trial Registration

PROSPERO CRD42020209187; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=209187

International Registered Report Identifier (IRRID)

RR1-10.2196/33989

Vitamin C Intervention for Critical COVID-19: A Pragmatic Review of the Current Level of Evidence

Severe respiratory infections are characterized by elevated inflammation and generation of reactive oxygen species (ROS) which may lead to a decrease in antioxidants such as vitamin C and a higher requirement for the vitamin. Administration of intravenous vitamin C to patients with pneumonia and sepsis appears to decrease the severity of the disease and potentially improve survival rate. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection causes pneumonia, sepsis and acute respiratory distress syndrome (ARDS) in severe cases, and is referred to as coronavirus disease 2019 (COVID-19). Patients with COVID-19 infection also appear to have depleted vitamin C status and require additional supplementation of vitamin C during the acute phase of the disease. To date there have been 12 vitamin C and COVID-19 trials published, including five randomised controlled trials (RCTs) and seven retrospective cohort studies. The current level of evidence from the RCTs suggests that intravenous vitamin C intervention may improve oxygenation parameters, reduce inflammatory markers, decrease days in hospital and reduce mortality, particularly in the more severely ill patients. High doses of oral vitamin C supplementation may also improve the rate of recovery in less severe cases. No adverse events have been reported in published vitamin C clinical trials in COVID-19 patients. Upcoming findings from larger RCTs will provide additional evidence on vitamin supplementation in COVID-19 patients.

Metabolic resuscitation in pediatric sepsis: a narrative review

Sepsis, defined as infection with associated organ dysfunction, accounts for most childhood deaths due to infection globally. Evidence for the optimal support of children with septic shock refractory to the initial sepsis management bundle remains minimal. There is an urgent need for more effective interventions. Administration of hydrocortisone in children with septic shock might fasten shock resolution, and has been shown to dampen the systemic host immune response, augment adrenergic effects, and support the stress response. Ascorbic acid (vitamin C) is one of the most powerful naturally occurring antioxidants and has beneficial effects on multiple pathways which are severely deranged during septic shock. A regimen combining hydrocortisone, ascorbic acid, and thiamine termed "metabolic resuscitation" or "HAT therapy" has been tested in large trials in critically ill adults with sepsis with conflicting results. Available information on intravenous ascorbic acid indicates an excellent safety profile even at very high doses both in adults and children. Given the pharmacological properties and beneficial effects shown both in vitro and in animal studies, and its safety profile, ascorbic acid either as a single therapy or as part of HAT treatment represents a promising candidate for future pediatric sepsis treatments. While pediatric age groups may be more susceptible to ascorbic acid deficiency during sepsis, there is a lack of high-quality trial data on HAT therapy in this age group. A single centre retrospective study identified potential for mortality benefit in children with septic shock, and the results from a randomized controlled pilot trial are being awaited. It is imperative for pediatric research on ascorbic acid and HAT in children with sepsis to critically investigate key questions related to pharmacology, dosing, timing, feasibility, safety, effects on short- and long-term outcomes, and generalisability in view of the global burden of sepsis.

Targeting Oxidative Stress in Septic Acute Kidney Injury: From Theory to Practice

Sepsis is the leading cause of acute kidney injury (AKI) and leads to increased morbidity and mortality in intensive care units. Current treatments for septic AKI are largely supportive and are not targeted towards its pathophysiology. Sepsis is commonly characterized by systemic inflammation and increased production of reactive oxygen species (ROS), particularly superoxide. Concomitantly released nitric oxide (NO) then reacts with superoxide, leading to the formation of reactive nitrogen species (RNS), predominantly peroxynitrite. Sepsis-induced ROS and RNS can reduce the bioavailability of NO, mediating renal microcirculatory abnormalities, localized tissue hypoxia and mitochondrial dysfunction, thereby initiating a propagating cycle of cellular injury culminating in AKI. In this review, we discuss the various sources of ROS during sepsis and their pathophysiological interactions with the immune system, microcirculation and mitochondria that can lead to the development of AKI. We also discuss the therapeutic utility of N-acetylcysteine and potential reasons for its efficacy in animal models of sepsis, and its inefficacy in ameliorating oxidative stress-induced organ dysfunction in human sepsis. Finally, we review the pre-clinical studies examining the antioxidant and pleiotropic actions of vitamin C that may be of benefit for mitigating septic AKI, including future implications for clinical sepsis.

Therapeutic potential of megadose vitamin C to reverse organ dysfunction in sepsis and COVID-19

Sepsis induced by bacteria or viruses can result in multiorgan dysfunction, which is a major cause of death in intensive care units. Current treatments are only supportive, and there are no treatments that reverse the pathophysiological effects of sepsis. Vitamin C has antioxidant, anti‐inflammatory, anticoagulant and immune modulatory actions, so it is a rational treatment for sepsis. Here, we summarise data that support the use of megadose vitamin C as a treatment for sepsis and COVID‐19. Megadose intravenous sodium ascorbate (150 g per 40 kg over 7 h) dramatically improved the clinical state and cardiovascular, pulmonary, hepatic and renal function and decreased body temperature, in a clinically relevant ovine model of Gram‐negative bacteria‐induced sepsis. In a critically ill COVID‐19 patient, intravenous sodium ascorbate (60 g) restored arterial pressure, improved renal function and increased arterial blood oxygen levels. These findings suggest that megadose vitamin C should be trialled as a treatment for sepsis and COVID‐19.

Resuscitation in Paediatric Sepsis Using Metabolic Resuscitation-A Randomized Controlled Pilot Study in the Paediatric Intensive Care Unit (RESPOND PICU): Study Protocol and Analysis Plan

Introduction: Septic shock remains amongst the leading causes of childhood mortality. Therapeutic options to support children with septic shock refractory to initial resuscitation with fluids and inotropes are limited. Recently, the combination of intravenous hydrocortisone with high dose ascorbic acid and thiamine (HAT therapy), postulated to reduce sepsis-related organ dysfunction, has been proposed as a safe approach with potential for mortality benefit, but randomized trials in paediatric patients are lacking. We hypothesize that protocolised early use of HAT therapy ("metabolic resuscitation") in children with septic shock is feasible and will lead to earlier resolution of organ dysfunction. Here, we describe the protocol of the Resuscitation in Paediatric Sepsis Using Metabolic Resuscitation-A Randomized Controlled Pilot Study in the Paediatric Intensive Care Unit (RESPOND PICU). Methods and Analysis: The RESPOND PICU study is an open label randomized-controlled, two-sided multicentre pilot study conducted in paediatric intensive care units (PICUs) in Australia and New Zealand. Sixty children aged between 28 days and 18 years treated with inotropes for presumed septic shock will be randomized in a 1:1 ratio to either metabolic resuscitation (1 mg/kg hydrocortisone q6h, 30 mg/kg ascorbic acid q6h, 4 mg/kg thiamine q12h) or standard septic shock management. Main outcomes include feasibility of the study protocol and survival free of organ dysfunction censored at 28 days. The study cohort will be followed up at 28-days and 6-months post enrolment to assess neurodevelopment, quality of life and functional status. Biobanking will allow ancillary studies on sepsis biomarkers. Ethics and Dissemination: The study received ethical clearance from Children's Health Queensland Human Research Ethics Committee (HREC/18/QCHQ/49168) and commenced enrolment on June 12th, 2019. The primary study findings will be submitted for publication in a peer-reviewed journal. Trial Registration: Australian and New Zealand Clinical Trials Registry (ACTRN12619000829112). Protocol Version: V1.8 22/7/20.

The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19

From Pauling's theories to the present, considerable understanding has been acquired of both the physiological role of vitamin C and of the impact of vitamin C supplementation on the health. Although it is well known that a balanced diet which satisfies the daily intake of vitamin C positively affects the immune system and reduces susceptibility to infections, available data do not support the theory that oral vitamin C supplements boost immunity. No current clinical recommendations support the possibility of significantly decreasing the risk of respiratory infections by using high-dose supplements of vitamin C in a well-nourished general population. Only in restricted subgroups (e.g., athletes or the military) and in subjects with a low plasma vitamin C concentration a supplementation may be justified. Furthermore, in categories at high risk of infection (i.e., the obese, diabetics, the elderly, etc.), a vitamin C supplementation can modulate inflammation, with potential positive effects on immune response to infections. The impact of an extra oral intake of vitamin C on the duration of a cold and the prevention or treatment of pneumonia is still questioned, while, based on critical illness studies, vitamin C infusion has recently been hypothesized as a treatment for COVID-19 hospitalized patients. In this review, we focused on the effects of vitamin C on immune function, summarizing the most relevant studies from the prevention and treatment of common respiratory diseases to the use of vitamin C in critical illness conditions, with the aim of clarifying its potential application during an acute SARS-CoV2 infection.