A Clinical Study On The Application Of Bispectral Index (BIS) During Anesthesia Intubation And Extubation

Objectives To study the relationship between the changes of bispectral index(BIS) and hemodynamic during anesthesia induction,to observe the changes of BIS in detecting transitions in consciousness during anesthesia induction and analepsia,and to investigate the effect of Fentanyl on BIS and Hemodynamic changes of general anesthesia patients during trachea extubation.Methodsâ‘ Experiment 1:Fifty patients who had graded ASAâ… -â…¡degree and undergoed radical gastrectomy for stomach cancer were selected.Anesthesia was induced in all patients with midazolam, fentanyl,vecuronium and propofol in order and maintained with isofluran.BIS and MAP(mean arterial pressure),HR(Heart Rate ) were recorded at the time points of before induction(To),before intubation(T₁),during intubation(T₂),at 1 min(T₃),2 min(T₄),3min(T₅) and 5min(T₆) after intubation,and at the same time BIS was recorded at the points of consciousness disappearance(T_a),the end of operation(T_b),analepsia (T_c),and out of PACU(T_d)â‘¡Experiment 2:Fifty patients,gradedASAâ… -â…¡degree undergoing radical gastrectomy for stomach cancer surgery,were fentanyl group.The fifty patients of the experiment 1 were placebo group.Anesthesia was induced and maintained in the way of experiment 1.Before the end of operation,Fent(1μg/kg) or an equivalent volume of saline was given to groups respectively.Tracheal extubation was performed when standard criterion was achieved.To observe the Changes of BIS and Hemodynamic changes.Results(1) The tendency of hemodynamic changes was similar to that of BIS.But the change of BIS was later than the change of hemodynamics.MAP and HR at T3 were higher than those at the T1(P＜0.05),which recovered to the levels before intubation at 5 min after intubation:BIS had no variation at T2,it began to go up at T3 and was most significant at T4(P＜0.05).(2)BIS was gradually ascend during inducation and decent during analepsia.BIS was 77 at Tc,the P₂₅- P₇₅ was between 69 and 76 at Tb,the P₂₅- P₇₅ was between 72 and 80 at Tc,and the overlapping is obvious at the two time points.(3) Before and after trachea extubation MAP and HR changes were significantly fewer in Fent group than in Control group(P＜0.05).There were no different in BIS.Conclusionâ‘ The tendency of hemodynamic changes was similar to that of BIS.The change of BIS was later than the change of MAP and HR.BIS monitoring is of few significance in evaluating hemodynamic changes during analepsia.â‘¡BIS was gradually ascend during inducation and decent during analepsia.BIS is of more significance in evaluating during anesthesia induction than those during anesthesia.â‘¢Fentanyl can alleviate the stress reaction during trachea extubation,but not affect analepsia degree.