| Objective: To explore the effects of different doses of remifentanil combined with Sevoflurane on baroreflex sensitivity(BRS)in patients with general anesthesia,and whether the effects are dose-dependent.At the same time,it was explored whether different doses of remifentanil combined with sevoflurane affected renin,angiotensin 2and aldosterone levels in RAAS system,and whether such effects were dose-dependent,so as to further explore the mechanism of remifentanil’s effect on BRS.Methods: 45 male patients with elective general anesthesia were selected,successfully completed the experiment.The patients had ASA grade Ⅰ ～ Ⅱ,no history of systemic diseases such as hypertension,diabetes,coronary heart disease,and no drugs affecting the RAAS system in the past 2 weeks.The patients were randomly divided into3 groups(n=15 cases): remifentanil plasma target concentration of 1 ng/mL group(R1group),remifentanil plasma target concentration of 4 ng/mL group(R4 group),and remifentanil plasma target concentration of 7 ng/mL group(R7 group).BRS value was calculated using the drug pressor reflex method.Specifically,50 ～ 200 ug of deoxyadrenalin was injected to increase blood pressure between 15 ～ 40 mm Hg.Systolic blood pressure and RR interval between the first significant rise in blood pressure and the end of the patient’s blood pressure were continuously recorded and depicted as scatter plots.The systolic blood pressure rise value(Δ SBP)and the extension value of RR interval(ΔRR)were regression analyzed,and the regression equation was obtained.The correlation coefficient of the regression equation r was > 0.7 ～ 0.8,and the slope could be used as the BRS value in ms/mm Hg.BRS values were measured at two time points before anesthesia(T0)and after anesthesia,when sevoflurane reached 0.8 MAC and remifentanil reached the set target concentration(T1).At the same time,5 mL of central venous blood was collected from two time points,and plasma was extracted by centrifugation.The levels of renin,angiotensin 2 and aldosterone were detected by chemiluminescence method.Anesthesia induction was performed with 2 mg/kg propofol,0.3 μg/kg sufentanil and 0.6 mg/kg rocuronium bromide.Endotracheal intubation was performed after consciousness loss and muscle relaxation.After intubation,sevoflurane was opened and the concentration of sevoflurane was adjusted to 0.8 MAC.Mechanical ventilation was given during the operation,and sevoflurane,remifentanil and sufentanil were used to maintain anesthesia.All experimental data were collected before the operation,and drug concentration was adjusted according to the operation requirements to meet the operation requirements.Results: There was no significant difference in BRS values of R1,R4 and R7 groups at T0 time point(P > 0.05).The BRS value of the three groups at T1 was lower than T0.At T1 time point,the BRS value of R7 group was significantly lower than that of R1 group with the statistical differences(P < 0.05),and the BRS value of R1 group and R4 group,R4 group and R7 group was statistically significant(P < 0.05).There was no significant difference in the levels of renin,angiotensin 2 and aldosterone at T0 time point among three groups(P > 0.05).At T1 time point,there were statistically significant differences in renin,angiotensin 2 and aldosterone levels between R1 group and R7 group(P < 0.05),but no statistically significant differences in the three hormones between R1 group and R4 group,R4 group and R7 group(P > 0.05).Conclusions: 1.Different doses of remifentanil combined with sevoflurane inhibited BRS in a dose-dependent manner.The higher the target concentration of remifentanil,the lower the BRS value and the more obvious the inhibition.2.Different doses of remifentanil combined with sevoflurane affect the levels of renin,angiotensin 2 and aldosterone,and inhibit the overactivation of the three hormones.This effect may be dose-dependent,and the more obvious the effect becomes as the target concentration of remifentanil increases. |
PDF Full Text Request