Effect of Intravenous Injection of Vitamin C on Postoperative Pulmonary Complications in Patients Undergoing Cardiac Surgery: A Double-Blind, Randomized Trial

Endogenous and exogenous protection from surgically induced reactive oxygen and nitrogen species

Surgical intervention creates reactive oxygen species through diverse molecular mechanisms, including direct stimulation of immune-mediated inflammation necessary for wound healing. However, dysregulation of redox homeostasis in surgical patients overwhelms the endogenous defense system, slowing the healing process and damaging organs. We broadly surveyed reactive oxygen species that result from surgical interventions and the endogenous and/or exogenous antioxidants that control them. This study assimilates current reports on surgical sources of reactive oxygen and nitrogen species along with literature reports on the effects of endogenous and exogenous antioxidants in human, animal, and clinical settings. Although exogenous antioxidants are generally beneficial, endogenous antioxidant systems account for over 80% of total activity, varying based on patient age, sex, and health or co-morbidity status, especially in smokers, the diabetic, and the obese. Supplementation of exogenous compounds for support in surgical patients is thus theoretically beneficial, but a lack of persuasive clinical evidence has left this potential patient support strategy without clear guidelines. A more thorough understanding of the mechanisms of exogenous antioxidants in patients with compromised health statuses and pharmacokinetic profiling may increase the utility of such support in both the operating and recovery rooms.

Effects of penehyclidine hydrochloride combined with dexmedetomidine on pulmonary function in patients undergoing heart valve surgery: a double-blind, randomized trial

AIM

To investigate the effects of penehyclidine hydrochloride combined with dexmedetomidine on pulmonary function in patients undergoing heart valve surgery with cardiopulmonary bypass (CPB).

METHODS

A total of 180 patients undergoing elective heart valve surgery with CPB were randomly divided into four groups: 45 in group P (intravenous penehyclidine hydrochloride 0.02 mg/kg 10 min before anesthesia induction and at the beginning of CPB, total 0.04 mg/kg); 43 in group D (dexmedetomidine 0.5 μg/kg/h after induction of anesthesia until the end of anesthesia); 44 in group PD ( penehyclidine hydrochloride 0.04 mg/kg combined with dexmedetomidine 0.5 μg/kg/h intravenously during anesthesia); and 43 in group C (same amount of normal saline 10 min before and after anesthesia induction, to the end of anesthesia, and at the beginning of CPB). The main outcomes were the incidence and severity of postoperative pulmonary complications (PPCs). The secondary outcomes were: (1) extubation time, length of stay in intensive care, and postoperative hospital stay, and adverse events; and (2) pulmonary function evaluation indices (oxygenation index and respiratory index) and plasma inflammatory factor concentrations (tumor necrosis factor-α, interleukin-6, C-reactive protein and procalcitonin) during the perioperative period.

RESULTS

The incidence of PPCs in groups P, D and PD after CPB was lower than that in group C (P < 0.05), and the incidence in group PD was significantly lower than that in groups P and D (P < 0.05). The scores for PPCs in groups P, D and PD were lower than those in group C (P < 0.05).

CONCLUSION

Combined use of penehyclidine hydrochloride and dexmedetomidine during anesthesia reduced the occurrence of postoperative pulmonary dysfunction, and improved the prognosis of patients undergoing heart valve surgery with CPB.

TRIAL REGISTRATION

The trial was registered in the Chinese Clinical Trial Registry on 3/11/2020 (Registration No.: ChiCTR2000039610).

Scurvy: Rediscovering a Forgotten Disease

Scurvy is a nutritional deficiency caused by low vitamin C levels that has been described since ancient times. It leads to a varied presentation, affecting multiple organ systems due to its role in the biochemical reactions of connective tissue synthesis. Common manifestations include gingival bleeding, arthralgias, skin discoloration, impaired wound healing, perifollicular hemorrhage, and ecchymoses. Although there has been a dramatic reduction in the prevalence of scurvy in modern times owing to vitamin C supplementation and intake, sporadic cases still occur. In developed countries, it is mainly diagnosed in the elderly and malnourished individuals and is associated with alcoholism, low socio-economic status, and poor dietary habits. Scurvy has been an unusual cause of gastrointestinal (GI) bleeding among other GI manifestations. It can be adequately treated and prevented via vitamin C supplementation.

Association of Oral or Intravenous Vitamin C Supplementation with Mortality: A Systematic Review and Meta-Analysis

Mortality is the most clinically serious outcome, and its prevention remains a constant struggle. This study was to assess whether intravenous or oral vitamin C (Vit-C) therapy is related to reduced mortality in adults. Data from Medline, Embase, and the Cochrane Central Register databases were acquired from their inception to 26 October 2022. All randomized controlled trials (RCTs) involving intravenous or oral Vit-C against a placebo or no therapy for mortality were selected. The primary outcome was all-cause mortality. Secondary outcomes were sepsis, COVID-19, cardiac surgery, noncardiac surgery, cancer, and other mortalities. Forty-four trials with 26540 participants were selected. Although a substantial statistical difference was observed in all-cause mortality between the control and the Vit-C-supplemented groups (p = 0.009, RR 0.87, 95% CI 0.78 to 0.97, I² = 36%), the result was not validated by sequential trial analysis. In the subgroup analysis, mortality was markedly reduced in Vit-C trials with the sepsis patients (p = 0.005, RR 0.74, 95% CI 0.59 to 0.91, I² = 47%), and this result was confirmed by trial sequential analysis. In addition, a substantial statistical difference was revealed in COVID-19 patient mortality between the Vit-C monotherapy and the control groups (p = 0.03, RR 0.84, 95% CI 0.72 to 0.98, I² = 0%). However, the trial sequential analysis suggested the need for more trials to confirm its efficacy. Overall, Vit-C monotherapy does decrease the risk of death by sepsis by 26%. To confirm Vit-C is associated with reduced COVID-19 mortality, additional clinical random control trials are required.

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.

Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability in cardiac surgery with cardiopulmonary bypass

Cardiopulmonary bypass (CPB) depletes endogenous Vitamin C and generates oxidative stress in cardiac surgery. This study aimed to clarify whether Vitamin C supplementation reduces oxidant production and improves erythrocyte deformability in cardiac surgery with CPB. In a randomized and controlled design, 30 eligible patients undergoing cardiac surgery with hypothermic CPB were equally assigned to the Vitamin C group and control group. Subjects of the Vitamin C group and control group received an intravenous infusion of Vitamin C 20 mg·kg^-1 and a placebo during rewarming period of CPB, respectively. We measured the plasma level of reactive oxygen species (ROS) and phosphorylation levels of non-muscle myosin IIA (NMIIA) in erythrocyte membrane, as an index of erythrocyte deformability, before and after CPB. Vitamin C supplementation attenuated the surge in plasma ROS after CPB, mean 1.661 ± standard deviation 0.801 folds in the Vitamin C group and 2.743 ± 1.802 in the control group. The tyrosine phosphorylation level of NMIIA after CPB was upregulated in the Vitamin C group compared to the control group, 2.159 ± 0.887 folds and 1.384 ± 0.445 (P = 0.0237). In addition, the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and focal adhesion kinase (FAK) in erythrocytes was concurrently enhanced in the Vitamin C group after CPB. The phosphorylation level of endothelial nitric oxide synthase in erythrocytes was significantly increased in the Vitamin C group (1.734 ± 0.371 folds) compared to control group (1.102 ± 0.249; P = 0.0061). Patients receiving Vitamin C had lower intraoperative blood loss and higher systemic vascular resistance after CPB compared to controls. Vitamin C supplementation attenuates oxidative stress and improves erythrocyte deformability via VASP/FAK signaling pathway in erythrocytes during CPB.

Treatment of SARS-CoV-2 (COVID-19): A safety perspective

The goal of this review is to report a balanced perspective of current evidence for efficacy of treatments for coronavirus disease 2019 (COVID-19) against the historical safety of these treatments as of May 2021. We preselected therapies of interest for COVID-19 based on national guidelines and modified over time. We searched PubMed and Medline for these specific COVID-19 treatments and data related to their efficacy. We also searched for prior randomized controlled trials of each therapy to assess adverse effects, and we obtained the Food and Drug Administration Approval label for this information. Several drugs have been approved for the treatment of COVID-19, and many more are under study. This includes dexamethasone, remdesivir, hydroxychloroquine/chloroquine, lopinvir/ritonavir, interferon or interleukin inhibitors, convalescent plasma and several vitamins and minerals. The strongest evidence for benefit is mortality benefit with dexamethasone in patients with COVID-19 and hypoxemia, although there is a signal of harm if this is started too early. There are several other promising therapies, like interleukin inhibitors and ivermectin. Hydroxychloroquine/chloroquine, lopinvir/ritonavir, and convalescent plasma do not have enough evidence of benefit to outweigh the known risks of these drugs.

Vitamin C in Critically Ill Patients: An Updated Systematic Review and Meta-Analysis

Background: Vitamin C is a water-soluble antioxidant vitamin. Oxidative stress and its markers, along with inflammatory markers, are high during critical illness. Due to conflicting results of the published literature regarding the efficacy of vitamin C in critically ill patients, and especially the concerns for nephrotoxicity raised by some case reports, this meta-analysis was carried out to appraise the evidence and affirmation regarding the role of vitamin C in critically ill patients. Methods: We searched the database thoroughly to collect relevant studies that assessed intravenous vitamin C use in critically ill patients published until 25 February 2021. We included randomized controlled trials and observational studies with 20 or more critically ill patients who have received intravenous ascorbic acid (vitamin C). After screening 18,312 studies from different databases, 53 were included in our narrative synthesis, and 48 were included in the meta-analysis. We used the Covidence software for screening of the retrieved literature. Review Manager (RevMan) 5.4 was used for the pooling of data and Odds Ratios (OR) and Mean difference (MD) as measures of effects with a 95% confidence interval to assess for explanatory variables. Results: Pooling data from 33 studies for overall hospital mortality outcomes using a random-effect model showed a 19% reduction in odds of mortality among the vitamin C group (OR, 0.81; 95% CI, 0.66–0.98). Length of hospital stay (LOS), mortality at 28/30 days, ICU mortality, new-onset AKI and Renal Replacement Therapy (RRT) for AKI did not differ significantly across the two groups. Analysis of data from 30 studies reporting ICU stay disclosed 0.76 fewer ICU days in the vitamin C group than the placebo/standard of care (SOC) group (95% CI, −1.34 to −0.19). This significance for shortening ICU stay persisted even when considering RCTs only in the analysis (MD, −0.70; 95% CI, −1.39 to −0.02). Conclusion: Treatment of critically ill patients with intravenous vitamin C was relatively safe with no significant difference in adverse renal events and decreased in-hospital mortality. The use of vitamin C showed a significant reduction in the length of ICU stays in critically ill patients.