Influence of sevoflurane concentration and stimulation voltage on motor evoked potentials in intraspinal tumor surgery / 北京大学学报(医学版)

Objective:To evaluate the effects of increasing end-tidal concentrations of sevoflurane and increasing stimulation voltage on motor evoked potentials,so as to provide evidence in making anesthesia plan for intraspinal tumor surgery.Methods:In the study,48 patients scheduled to undergo intraspinal tumor surgery [American Society of Anesthesiology,(ASA)Ⅰ-Ⅱ,18-65 years old]were enrolled. After general anesthesia induction,the patients were assigned to receive sevoflurane anesthesia of increa-sing end-tidal concentration in the sequence of 0.0%,0.5%,1 .0% and 1 .5% respectively,under a background of propofol and remifentanil.All the observations were done before the important steps of sur-gery.Remifentanil infusion rate was 0.2 μg /(kg·min),while the propofol infusion rate was adjusted to maintain the bispectral index values within the range of 30-50.At each concentration,4 stimulation voltages of 300 V,400 V,500 V and 600 V were employed to elicit motor evoked potentials (MEPs). The amplitude and latency of each MEP were compared.The success ratio was also recorded.Results:The concentration of sevoflurane and the stimulation voltage had impacts on the amplitude and latency of MEPs.Under each stimulation voltage,the MEPs amplitude decreased following increasing end-tidal sevoflurane concentrations,and significant differences were found in comparing 1 .5% sevoflurane (left 20.50 μV,70.71 μV,135.97 μV,190.00μV ,right 14.29 μV,50.71 μV,73.10μV,77.50μV) with 0.0% sevoflurane (left 143.00 μV,388.10 μV,484.53 μV,500.00 μV,right 176.00 μV, 407.60 μV,384.35 μV,451.00 μV)and 0.5% sevoflurane (left 100.00 μV,362.57 μV,444.05μV,435.00 μV,right 115.00 μV,207.15 μV,258.34 μV,358.50 μV),left χ2 =27.46,P<0.01,right χ2 =60.49,P<0.01;left χ2 =20.73,P<0.01,right χ2 =55.05,P<0.01;left χ2 =34.25,P<0.01,right χ2 =33.58,P<0.01;left χ2 =28.61,P<0.01 ,right χ2 =49.04,P<0.01;while there were no statistical differences in the latency changes (P =0.26 ).Under each end-tidal sevoflurane concentration,the MEPs amplitude increased following increasing stimulation voltages,and significant differences were found in comparing 300 V (left 143.00 μV,100.00 μV,61.50 μV,20.50μV ,right 176.00 μV,115.00 μV,41.07 μV,14.29 μV)with 400 V (left 388.10 μV,362.57μV,198.81 μV,70.71 μV,right 407.60 μV,207.15 μV,89.00 μV,50.71 μV)and 500 V (left 484.53 μV,444.05 μV,216.24μV,135.97 μV,right 384.35 μV,258.34μV,187.50μV,73.10μV)and 600 V (left 500.00 μV,435.00 μV,344.00 μV,190.00 μV,right 451.00 μV,385.50μV,156.00μV,77.50μV),leftχ2 =45.55,P<0.01,rightχ2 =25.73,P<0.01;leftχ2 =46.67, P<0.01,right χ2 =55.30,P<0.01;left χ2 =47.36,P<0.01,right χ2 =47.82,P<0.01;left χ2 =38.67,P<0.01,right χ2 =45.87,P<0.01;while the latencies were decreased,and significant dif-ferences were found in comparing 300 V with 400 V and 500 V and 600V(left F=7.50,P=0.01 ,right F=13.33,P<0.01),but the differences had little clinical significance.The success ratio decreased by increasing end-tidal sevoflurane concentration,and significant differences were found in comparing 1 .5%sevoflurane (left 43.8%,70.8%,77.1%,81.3%,right 37.5%,60.4%,75.0%,66.7%)with 0.0%sevoflurane (left 79.2%,87.5%,95.8%,93.8%,right 75.0%,95.8%,95.8%,95.8%)and 0.5%sevoflurane (left 72.9%,89.6%,95.8%,95.8%,right 66.7%,89.6%,95.8%,97.9%);the suc-cess ratio increased by increasing stimulation voltage,and significant differences were found in comparing 300 V(left 79.2%,72.9%,62.5%,43.8%,right 75.0%,66.7%,60.4%,37.5%)with 400 V(left 87.5%,89.6%,77.1%,70.8% ,right 95.8%,89.6%,79.2%,60.4%)and 500 V(left 95.8%, 95 .8%,9 1 .7%,77 .1%,right 95 .8%,95 .8%,8 1 .3%,75 .0%)and 600 V (left 93 .8%,95 .8%, 89.6%,81.3%,right 95.8%,97.9%,89.6%,66.7%),but there were no statistical differences in the success ratio of MEPs between the group with stimulation voltage of 600 V ,end tidal sevoflurane concen-tration of 1 .5% and the group with stimulation voltage of 300 V,end tidal sevoflurane concentration of 0.0% (P=0.22).Conclusion:Sevoflurane inhibited MEPs in a dose-dependent manner.It can de-crease the amplitudes and prolong the latencies.But increasing stimulation voltage will facilitate MEPs monitoring and increase the success ratio.Sevoflurane can be used in larger parts of MEPs monitoring surgery by increasing the stimulation voltage.

Progress of Anesthetic Management of Robotic Totally Endoscopic Coronary Artery Bypass on Beating Heart / 中国微创外科杂志

[Summary] Robotic totally endoscopic coronary artery bypass on beating heart (BH-TECAB), a minimally invasive surgical approach with rapid postoperative recovery , is becoming the future trend of minimally invasive coronary surgery , which demands a higher standard for anesthetic management . It comprises pressured pneumothorax , unilateral lung ventilation , transesophageal echocardiography monitoring , hemodynamics maintaining , preparation for cardiopulmonary bypass and conversion to sternotomy , and ventricular fibrillation treatment , which require anesthesiologists to achieve more refined perioperative management and pathophysiological regulation .

Effects of atracurium on facial nerve monitoring during otologic operations / 中国微创外科杂志

Objective To investigate the effects of neuromuscular blockade(NMB) by atracurium on facial nerve monitoring.Methods Twenty patients with chronic otitis media scheduled for radical mastoidectomy under general anesthesia were selected.Anesthetic inducement was made with sufentanil at 0.4 ?g/kg,lidocaine at 0.5~1 mg/kg,propofol at 2 mg/kg,and scoline at 1.5 mg/kg in their given order intravenously.After endotracheal intubation,mechanical ventilation was employed with an anesthetic machine.Intraoperative facial nerve minitorization was performed using the neuromuscular transmission monitor(TOF Guard) and the NMB level of right musculus adductor pollicis was assessed with the Nerve Integrity Monitoring System(Medtronic Inc.) simultaneously.No muscle relaxants were given until the electromyogram(EMG) of the facial nerve was induced.Propofol and sufentanil was administered intravenously to maintain the anesthesia.Minimal facial nerve stimulations(regarded as thresholds) causing EMG responses were measured during both nil NMB and 100% NMB by atracurium at 0.5 mg/kg.Results With propofol and sufentanil intravenously administered,the anesthesia was maintained successfully both before and after the administration of atracurium.The EMG of the facial nerve was induced even during the 100% NMB level by atracurium,but the thresholds were elevated significantly from 0.22?0.09 mA to 0.39?0.17 mA(t=-8.643,P=0.000).Conclusions Facial nerve monitoring can be performed even during the 100% NMB level by atracurium,with significant elevated stimulating thresholds.Propofol and sufentanil can be used to maintain adequate level of anesthesia without the need of muscle relaxants in radical mastoidectomy.

Effects of retroperitoneal carbon dioxide insufflation on the balance of cerebral oxygen metabolism / 中国微创外科杂志

0.05). Conclusions Following retroperitoneal laparoscopy, the cerebral blood flow is increased and no cerebral anoxia is found.

Effect of continuous epidural block on sympathetic neural activity during desflurane anesthesia / 中华麻醉学杂志

Objective To evaluate the prophylactic effect of continuous epidural block combined with desflurane anesthesia on increase of sympathetic neural activity induced by desflurane Methods Thirty patients were randomly allocated to two groups: desflurane anesthesia (DA) group (n=15) and epidural block combined with desflurane anesthesia (ECDA) group (n=15) After rapid induction with fentanyl propofol scoline, in DA group 2% desflurane in oxygen was inhaled firstly, then imposed with successive 1% increase of desflurane until balance and in ECDA group epidural blockade at T 9 10 or T 10 11 was firstly performed with 2% lidocain and other procedures were same as DA group The central venous blood samples were taken before induction, 30 min following desflurane inhalation(T 1), 60 min after operation beginning(T 2) and at the end of operation(T 3), to measure the plasma conentrations of catecholamine with high performance liquid chromatography Results Compared with baseline, following desflurane inhalation, MAP increased in DA group, but decreased in ECDA group, with significant difference between both groups As compared with the baselines, plasma epinephrine (EPI) and norepinephrine (NE) concentrations increased significantly in DA group at T 1, T 2 and T 3, but in ECDA group remained unsignificant changes at T 1, rose markedly at T 2 and T 3 EPI and NE levels were evidently higher in DA group at T 1 and T 2 than those in ECDA group Conclusions Continuous epidural blockade can effectively prevent the increasing in sympathetic neural activity induced by desflurane