Intraoperative Vitamin C Reduces the Dosage of Propofol in Patients Undergoing Total Knee Replacement

Purpose: Propofol is commonly used as an intravenous anesthetic in surgical patients. However, its usage is associated with adverse effects. Auxiliary medication can reduce the dose of intravenous anesthetics. Hence, we investigated whether vitamin C could lower propofol dosage in elderly patients undergoing total knee replacement surgery. Patients and Methods: The trial was carried out in PLA General Hospital in Beijing, China. We enrolled patients aged ≥ 50 years who were undergoing unilateral total knee arthroplasty with total intravenous anesthesia combined with lumbar sciatic nerve block. The patients were randomly assigned to either the vitamin C (Vc) group (0.067 g/kg) or the control group (an equivalent dose of normal saline). Nerve block was done for all the patients before the general anesthesia. The same depth of anesthesia was maintained during the operation. We compared the propofol dosage and adverse events (eg hypotension) during anesthesia between the two groups. This study was registered with the Chinese Clinical Trial Registry, www.chictr.org.cn , number ChiCTR-TRC-16010112. Results: There were significant differences in the total infusion dose (Vc group: 704.3 ± 188.6 mg; control group: 888.6 ± 232.7 mg; p = 0.016) and the average maintenance dose of propofol (Vc group: 5.8 ± 1.0 mg/kg/h; control group: 6.9 ± 1.6 mg/kg/h; p = 0.013). But there were no significant differences in the induction dose of propofol (control group: 90 mg, range 80– 115 mg; Vc group: 100 mg, range 90– 110 mg, p = 0.379) between the Vc and control groups. Furthermore, there were no significant differences in the hemodynamics and the incidence of intraoperative hypotension. Conclusion: Vitamin C can reduce the dosage of propofol in patients undergoing total knee replacement.