Background: Cardiac surgery is associated with oxidative stress and systemic inflammation, which both contribute to postoperative organ dysfunction. Vitamin C is a pleiotropic, antioxidant, and potentially organ-protective micronutrient. Past clinical trials and meta-analyses have focused predominantly on occurrence of postoperative atrial fibrillation. Therefore, we investigated the influence of perioperative vitamin C administration on clinically relevant parameters closer related to the patient’s recovery, especially organ function, and overall outcomes after cardiac surgery. Methods: Randomized controlled trials (RCTs) comparing perioperative vitamin C administration versus placebo or standard of care in adult patients undergoing cardiac surgery were identified through systematic searches in Pubmed, EMBASE, and CENTRAL on 23 November 2018. Published and unpublished data were included. Assessed outcomes include organ function after cardiac surgery, adverse events, in-hospital mortality, intensive care unit, and hospital length-of-stay. Data was pooled only when appropriate. Results: A total of 19 RCTs with 2008 patients were included in this meta-analysis. Vitamin C significantly decreased the incidence of atrial fibrillation (p = 0.008), ventilation time (p < 0.00001), ICU length-of-stay (p = 0.004), and hospital length-of-stay (p < 0.0001). However, on average, vitamin C had no significant effects on in-hospital mortality (p = 0.76), or on the incidence of stroke (p = 0.82). High statistical heterogeneity was observed in most analyses. Conclusions: Vitamin C impacts clinically and economically important outcomes, such as ICU and hospital length-of-stay, duration of mechanical ventilation and lowers the incidence of atrial fibrillation. Due to missing reports on organ dysfunction, this meta-analysis cannot answer the question, if vitamin C can improve single- or multiorgan function after cardiac surgery.

While medical nutrition therapy is an essential part of the care for critically ill patients, uncertainty exists about the right form, dosage, timing and route in relation to the phases of critical illness. As enteral nutrition (EN) is often withheld or interrupted during the ICU stay, combined EN and parenteral nutrition (PN) may represent an effective and safe option to achieve energy and protein goals as recommended by international guidelines. We hypothesize that critically ill patients at high nutritional risk may benefit from such a combined approach during their stay on the intensive care unit (ICU). Therefore, we aim to test if an early combination of EN and high-protein PN (EN+PN) is effective in reaching calorie and protein goals in patients at high nutritional risk, while avoiding overfeeding. This approach will be tested in the here presented EFFORTcombo trial. Nutritionally high-risk ICU patients will be randomized to either high (≥2.2 mg/kg/d) or low protein (≤1.2 mg/kg/d). In the high protein group, the patients will receive EN+PN, in the low protein group, patients will be given EN alone. EN will be started in accordance to international guidelines in both groups. Efforts will be made to reach nutrition goals within 48–96 hours. The efficacy of the proposed nutritional strategy will be tested as an innovative approach by functional outcomes at ICU- and hospital-discharge, as well as at a 6-month follow-up.

The authors thank the readers for pointing out the issues [...]