Perioperative Vitamin C and E levels in Cardiac Surgery Patients and Their Clinical Significance

Abstract

Background: Oxidative stress contributes to organ dysfunction after cardiac surgery and still represents a major problem. Antioxidants, such as vitamins C and E might be organ protective.

Methods: The primary objective of this prospective observational study was the description to evaluate the perioperative vitamin C and E levels in 56 patients undergoing cardiac surgery with the use of cardiopulmonary bypass. The association of vitamin C with inflammatory reaction, oxidative stress, organ dysfunctions, and clinical outcomes were evaluated in an explorative approach.

Results: Vitamin C levels decreased significantly from 6.5 (3.5-11.5) mg/L before surgery to 2.8 (2.0-3.9) mg/L 48 h after surgery (p < 0.0001). Fifty-six percent of patients had a suboptimal vitamin C status even before surgery. In protein-denaturized probes, significantly higher vitamin C concentrations were detected (p = 0.0008). Vitamin E levels decreased significantly from preoperative level 11.6 (9.5-13.2) mg/L to 7.1 (5.5-7.4) mg/L, (p = 0.0002) at the end of cardiopulmonary bypass, remained low during the first day on ICU and recovered to 8.2 (7.1-9.3) mg/L 48 h after surgery. No patient was vitamin E deficient before surgery. Analysis showed no statistically significant association of vitamin C with inflammation, oxidative stress or organ dysfunction levels in patients with previously suboptimal vitamin C status or patients with a perioperative decrease of ≥50% vitamin C after surgery. Patients with higher vitamin C levels had a shorter ICU stay than those who were vitamin C depleted, which was not statistically significant (72 versus 135 h, p = 0.1990).

Conclusion: Vitamin C and E levels significantly declined intraoperatively and remained significantly reduced low for 2 days after cardiac surgery. The influence of reduced serum levels on the inflammatory reaction and clinical outcome of the patients remain unclear in this small observational study and need to be investigated further. Given vitamin C´s pleiotropic role in the human defense mechanisms, further trials are encouraged to evaluate the clinical significance of Vitamin C in cardiac surgery patients.

Keywords: ascorbic acid; cardiac surgery; critical care; observational study; organ failure; prospective study; vitamin E.

Figure 1

Patient flowchart. N, number of patients.

Figure 2

Perioperative course of vitamin E. CPB, cardiopulmonary bypass; ICU, intensive care unit; N, number of patients. Circles represent outliers.

Figure 3

Perioperative course of vitamin C with different probe handling. CPB, cardiopulmonary bypass; ICU, intensive care unit; N, number of patients. Circles represent outliers.

Figure 4

Association of perioperative vitamin C levels with leukocytes (A,B), SOFA Score (C,D), CRP (E,F), and PCT (G,H). N, number of patients; (A,C,E,G) patients with preoperative vitamin C deficit; (B,D,F,H) patients with intraoperative loss of vitamin C ≥ 50%. Circles represent outliers.

Figure 5

Association of perioperative vitamin C levels with interleukin 6 (IL6) (A,B) and interleukin 10 (IL10) (C,D). N, number of patients; (A,C), patients with preoperative vitamin C deficit; (B,D), patients with intraoperative loss of vitamin C ≥ 50%. Circles represent outliers.

Figure 6

Association of perioperative vitamin C levels with oxidative stress, assessed as oxidation–reduction potential (ORP) (A,B) and anti-oxidative capacity (C,D). N, number of patients; (A,C), patients with preoperative vitamin C deficit; (B,D), patients with intraoperative loss of vitamin C ≥ 50%. Circles represent outliers.

Figure 7

Association of perioperative vitamin C levels with fluid balance. (A) Patients with preoperative vitamin C deficit and (B) patients with intraoperative loss of vitamin C ≥ 50%. N, number of patients. Circles represent outliers.