The Effects Of Intermittent Whole-body Hypoxic Preconditioning On Patients With Carotid Artery Stenosis

Objective: To study the effects of intermittent whole-body hypoxic preconditioning on patients with carotid artery stenosis.Methods: Screening 50 patients with carotid artery stenosis according to the screening criteria,randomly divided into the hypoxic intervention group(HIG)and the control group(CG),with 25 subjects per group.The HIG subjects were treated with an 18% oxygen concentration through a hypoxic respiration device for 30 min every morning and afternoon for 7 days before the operation,and the CG used the same device with a 21% oxygen concentration at the same times.Heart rate,blood pressure,respiratory rate and arterial oxygen saturation were monitored before,during and 5 min after the intervention with an electrocardiogram monitor.Fasting venous blood samples(4 m L each)were collected from the subjects on their first morning after joining the trial(preoperative samples)and the first morning after the operation(postoperative samples)for laboratory testing.The hemoglobin content,serum aspartate transaminase(AST)concentration,serum alanine aminotransferase(ALT)concentration,serum creatinine(Scr)concentration and blood urea nitrogen(BUN)concentration at each time point were measured by the clinical laboratory of Tianjin Huanhu Hospital.The concentrations of hypoxia-inducible factor-1α(HIF-1α),erythropoietin(EPO),vascular endothelial growth factor(VEGF),neuron-specific enolase(NSE),S100β protein and brain-derived neurotrophic factor(BDNF)were measured using enzyme-linked immunosorbent assay(ELISA)kits according to the manufacturer’s instructions.All subjects were followed up for 3 months after the trial,average length of hospital stay and postoperative complications were counted.Results:1.Changes in vital signs surrounding the intervention process in the HIG and CGDuring the intervention,the respiration rate,heart rate and systolic pressure of the HIG were significantly higher than those of the CG(P < 0.05 for each),and the arterial oxygen saturation of the HIG was lower than that of the CG(P < 0.05).2.Changes in hemoglobin content,HIF-1α concentration,EPO concentration and VEGF concentration in the HIG and CGIn the HIG,postoperative concentrations of hemoglobin,EPO,HIF-1α and VEGF were significantly higher than preoperative(P < 0.05 for each).3.Changes in BDNF,NSE and S100β concentrations in the HIG and CGIn the CG,the postoperative concentrations of NSE and S100β were higher than the preoperative values(P < 0.05).4.Changes in AST,ALT,Scr and BUN concentrations in the HIG and CGThe preoperative AST,ALT,Scr and BUN concentrations in the HIG and CG did not significantly differ from the postoperative values the same groups(P > 0.05),and all of the above indexes were within the normal range.5.The incidence of adverse events in the HIG and CGThe incidences of the headache and dizziness,palpitation and shortness of breath,fatigue and weakness were 20%,48%,36%,separately.6.Average length of hospital stay and postoperative complicationsThere was no significant difference in the length of hospitalization and the incidence of postoperative complications between the two groups.Conclusion:1.The oxygen concentration in the gas inhaled by the HIG was controlled at approximately 18%,and it had changed the subjects’ vital signs of hypoxic preconditioning can affect the subjects’ vital signs.These changes indicate that the body underwent a stress response to hypoxia stimulation.2.The changes in the hematological indexes suggest that the goal of hypoxic preconditioning was achieved.3.Hypoxic intervention did not cause additional damage to the neurological function of the HIG subjects and may improve the prognosis for neurological function.4.Hypoxic preconditioning trial did not cause liver or kidney dysfunction in subjects and that the trial was safe and reliable.