Effects Of Sevoflurane On Relaxation Produced By Cisatracurium

ObjectiveTo evaluate the potentiation of neuromuscular blockade produced by cisatracurium during sevoflurane anesthesia.Observing the clinical action time and recovery time's change with the increased concentration of sevoflurane,so we can guide the dose of the cisatracurium when combined with sevoflurane,preventing the residue of the neuromuscular blockade.MethodsSixty ASAâ… orâ…¡patients scheduled for elective surgery under general anesthesia, body mass index was between 18～30kg/m².Exclusion criteria were:Patients with disfunction of heart,lung,liver,kidney,those people who have a history of neuromuscular disease,those people who have a serious anemia or take the medicine that can influence the neuromuscular blocking drugs,those people who have an individual or family history of malignant hyperthermia,those people who have a recent history of burning or serious trauma,those people who were susceptible to neuromuscular blocking drugs,those people who have a history of chronic alcohol or drug abuse,those with a body mass index＞30 kg/m² or＜18kg m²ã€‚Sixty patients were randomly allocated into 4 groups(n=15 each);groupâ… control(P);groupâ…¡inhaling 1% sevoflurane(S₁);groupâ…¢inhaling 1.5%sevoflurane(S_1.5);groupâ…£inhaling 2% sevoflurane(S₂).Monitoring the ECG,SBP/DBP,S_PO₂.Anesthesia was induced with propofol 1～1.5 mg/kg,fentanyl 2～4ug/kg,Scoline 1mg/kg.Oro-or naso-tracheal intubation was accomplished under topical anesthesia.Anesthesia was maintained with inhalation of 67%N₂O in O₂ combined with propofol-remifentanil(P) or combined with 1%sevoflurane(S₁) or 1.5%sevoflurane(S_1.5) or 2%sevoflurane(S₂),fentanyl 0.05 mg or 0.1 mg was injected if needed.The patients were mechanically ventilated, regulating the tidal volume,respiratory frequency,make the partial pressure of carbon dioxide in end expiratory gas maintained by 4～5KPa.Thirty-five minutes after induction of anesthesia cisatracurium 0.15 mg/kg was given iv in each group.N-M function was monitored with accelerograph F(TOF-WatchSX,Organon,the Netherlands).The electrode was placed at wrist over the ulnar nerve.A train of four(TOF)stimulation of ulnar nerve was used,the current was 50mA,Th was defined as 100%,interval was 12s.The time from injection of cisatracurium to the twitch height depressed to 0(T₀) of control and to the twitch height recovering to 25%,50%,90% of control(RT₂₅,RT₅₀,RT₉₀) and recovery index(from RT₂₅-RT₇₅) were recorded.End-tidal sevoflurane concentration was monitored.ResultsThe four groups were comparable with respect to age and M/F ratio and body mass index.T₀ was significantly shorter in S₂ group than in group P,RT₂₅,RT₅₀,RT₉₀,RI were significantly longer in group S₁,S_1.5,S₂ than in group P;RT₂₅,RT₅₀,RT₉₀ were significantly longer in group S_1.5,S₂ than in group S₁,but has no effect on the recovery of N-M block between group S_1.5 and group S₂.ConclusionInhaling 2%sevoflurane can significantly shorten the onset time of cisatracurium, Inhaling 1%,1.5%,2%sevoflurane can significantly potentiates the neuromuscular blockade induced by cisatracurium,Inhaling 1.5%,2%sevoflurane can significantly potentiates the neuromuscular blockade induced by cisatracurium than Inhaling 1% sevoflurane.During the process of clinical anesthesia,we should not ingore the interaction between inhaling anesthesic and neuromuscular blocking drugs,we should correctly evaluate the degree of the neuromuscular blockade according to the actual situation of of the patients,handle the dose and the injection time of the neuromuscular blocking drugs,we should reduce the dose of the neuromuscular blocking drugs considering the characteristics that inhaling anesthetic can potentialize the neuromuscular blocking drugs,so we can make the neuromuscular blockade recover quickly.