Hemodynamic Effects And Mechanisms Of Remifentanil On New Zealand Rabbits Which Cut Off The Autonomic Nerve

Objective: By observing the influences including hemodynamics,ACh and NE of remifentanil on New Zealand rabbits which been cut off bilateral vagus nerve or sympathetic nerve to detect the channel of remifentanil on decrease heart rate and blood pressure.Further investigate the cardiovasculr depression mechanism of remifentanil,improve the management quality of perioperative anesthesia.Method: Select 40 healthy male New Zealand rabbits,weight 2 ~ 2.5 kg,randomly divided into 5 groups,including cut off vagus nerve group with remifentanil group(V+R-group,n=8),cut off sympathetic nerve with remifentanil group(S+R-group,n=8),cut off vagus nerve with NS group(V-group,n=8),cut off sym-pathetic nerve with NS group(S-group,n=8),nerve complete with remifentanil group(R-group,n=8).Intravenous inject 1 % pentobarbital sodium for general anesthesia,V+R-group and V-group cut off bilateral vagus nerve,S+R-group and S-group cut off bilateral sympathetic nerve.After the neural processing,V+R-group,S+R-group,R-group intravenous inject 5?g/kg remifentanil.Heart rate,ABP,the level of ACh and NE were measured at three points:after general anesthesia(T0),deal with autonomic nerve(T1)and after intravenous inject remifentanil 30 seconds(T2).Use satistically analyze for the data.Result: 1.V+R-group and R group HR: Compared to R-group T1(235.13 ±14.84),V+R-group was faster at T1(254.25±10.25),and the difference was statistically significant,(P<0.05).There was no significant difference between two groups at point T2.MAP: There was no significant statistical difference between two groups at T0 and T2,(P>0.05).The data showed a small increased at V+R-group T1(94.50±14.06)when compared with R-group T1(89.63±13.44),however,was not statistically significant,(P>0.05).ACh: There was no significant statistical difference between two groups at T0 and T1,(P>0.05).But R-group T2(14.01±5.31)was significantly higher than V+R-group T2(10.23±0.62).NE:T0(14.63±3.37)、T1(17.98±3.85)、T2(15.85±3.88)of two groups had no significant difference,(P>0.05).2.S+R-group and R-group HR: S+R-group T0(226.00±14.41),T2(198.00±8.70)had no significant difference when compared with R-group,(P>0.05).Only S+R-group T1(206.50±7.80)showed sharply decreased than R-group,and the difference was statistically significant,(P<0.05).MAP: There was no significant difference between two groups at every point,(P>0.05).ACh: S+R-group T2(17.17±0.76)was obvious higher than T1(12.76±0.67),T0(12.33±1.01),the difference was statistically significant,(P<0.05).NE: S+R-group T1(17.14±2.56)was significant less than T0(21.20±2.20),(P<0.05).There was no significant difference between two groups at every point,(P>0.05).3.V+R-group and V-group HR:V-group T1(258.88±14.72)was faster than T0(240.63±13.28),and the difference was statistically significant,(P<0.05).There was no significant difference between T2(254.13±14.5)and T1(258.8±14.72),(P>0.05).Only V+R-group T2(193.25±11.08)was obvious less than V-group T2(254.13±14.5),the difference was statistically significant,(P<0.05).MAP: V-group T1(94.88±5.14)was significant high than T0(82.75±6.71),(P<0.05).There was no significant change between T2(89.25±6.59)and T1(94.88±5.14),(P>0.05).Only V+R-group T2(74.00±3.59)was distinct lower than V-group T2(89.25±6.59),and the difference was statistically significant(P<0.05).ACh: There was no significant difference between two groups at every point,(P>0.05).NE: V-group T1(14.36±4.77)had no significant difference with T0(10.59±2.52),however,was not statistically significant,(P>0.05).V+R-group T0(14.63±3.37)was significant higher than V-group at the same point,(P<0.05).4.S+R-group and S-group HR: S-group T1(199.50±10.39)was significant slower than T0(228.88±15.07),(P<0.05).S+R-group T2(198.00±8.70)was lower than S-group T2(208.38±16.96),however,was not statistically significant,(P>0.05).MAP: S-group T1(68.38±6.57)has significant reduced when compared with T0(75.13±7.40),(P<0.05).ACh: S-group T1(12.78±0.96)has significant increased than T0(11.66±0.99),(P<0.05).S+R-group T2(17.17±0.76)was more than S-group T2(11.74±1.19),and the difference was statistically significant,(P<0.05).NE: S+R-group T0(21.20±2.20)was significant different from S-group T0(17.30±3.50),(P<0.05).Conclusion: Remifentanil can induce bradycardia and hypotension in cut bilateral sympathetic nerve rabbits,and the ACh content in blood was significant higher than control group.we infer that remifentanil can cause circulation inhibition by activating the vagus nerve.Remifentanil can aiso induce circulation inhibition in cut bilateral vagus nerve rabbits,but NE in plasma did not significantly alter.we can infer that the circulation inhibition caused by remifentanil is irrelevant to the Sympathetic nerve.