The effect of intravenous vitamin C infusion and evaluation of brain oxygenation with a cerebral oximetry in improving brain perfusion of diabetic patients during general anesthesia in vascular surgery

The effect of intravenous vitamin C infusion and evaluation of brain oxygenation with cerebral oximetry in improving brain perfusion of diabetic patients during general anesthesia in carotid endarterectomy surgery

This phases 3 clinical trial has a control group, with parallel groups, double-blind, randomized, on 50 patients, which are completely randomized by the method of block randomization in the form of quadruple blocks and non-blind, divide into two groups of vitamin C and placebo.

For patients' candidates for vascular surgery under general anesthesia referred to Ayatollah Taleghani Hospital in Tehran, a cerebral oximeter sensor is placed on both sides of the patient's forehead and continuous oxygenation measurement is started. The patient is placed in the supine position for 10 minutes. Before and after induction of anesthesia and at the end of the operation, heart rate, blood sugar, mean arterial blood pressure, oxygen saturation of brain tissue (rSO2, SpO2, PaCo2, ScO2, EtCO2) are measured.

Diabetic patients who are candidates for carotid endarterectomy under general anesthesia with the consent to participate in the project, age 50 years and older, ASA Class II are included in the study. Patients with dissatisfaction with participation in the plan, ASA class III and above, hemoglobin level less than 8 g/dl, brain failure, metabolic disease, and any type of intracranial pathology are excluded.

Placebo group: they will receive an infusion of 500 ml isotonic saline, half an hour before induction of anesthesia. Vitamin C group: They will receive an infusion of 1 gr of vitamin C diluted in 500 ml of isotonic saline, half an hour before induction of anesthesia.

rSO; SpO2; PaCo2; ScO2; EtCO2

In this study, we will use the restricted randomization method from type of block randomization. Blocking is usually used to balance the number of samples assigned to each of the study groups. This feature helps researchers to equate the number of samples assigned to each of the study groups in cases where intermediate analyzes are required during the sampling process. The size of all blocks is equal, and we will have 4 groups of 4 blocks (including 2 participants in the intervention group and 2 participants in the control group) in this two-group experiment. Randomization tool also uses random allocation software that these random sequence generation software in addition to simple randomization are able to generate random sequence by blocking method.

In this study, participants who were willing to participate in the project, as well as the clinical caregiver who was in charge of drug or placebo infusion and patient care, were blinded.