Effects of Vitamin C on Shock Duration and Microcirculation in Patients With Vasoplegia Syndrome After Cardiac Surgery

Vasoplegia syndrome is a frequent and severe complication after cardiac surgery (incidence 5-50%), marked by hypotension, normal/high cardiac index, and continuous vasopressor need, leading to prolonged ICU stay, acute kidney injury, and death. Its pathophysiology involves systemic inflammation, excessive nitric oxide, vasopressin depletion, and endothelial dysfunction impairing microcirculation.

Vitamin C, a potent antioxidant, scavenges reactive oxygen species, protects glycocalyx, supports norepinephrine synthesis, and limits iNOS expression, improving microperfusion in experimental models. Plasma vitamin C drops significantly after cardiopulmonary bypass, suggesting increased consumption and potential benefit.

However, clinical evidence is conflicting. Neither trial assessed microcirculatory endpoints, leaving this gap unexplored in randomized studies. Thus, this study aims to evaluate vitamin C's effects on both shock duration and sublingual microcirculation in post-cardiac surgery vasoplegia, addressing the unresolved clinical and mechanistic questions.

Inclusion criteria

• Age 18-85 years;
• Patients who develop vasoplegia syndrome within 6 hours after being admitted to the ICU following cardiac surgery
• Signing informed consent.

Exclusion criteria

included:

• Emergency surgery;
• Sepsis shock, postoperative cardiogenic shock or hemorrhagic shock;
• Pregnancy or lactation;
• Allergy to vitamin C;
• Inability to obtain clear sublingual microcirculatory images due to any cause;
• Judgment by the attending physician that the patient was unsuitable for enrollment.