The Effects Of Low-dose Sevoflurane Or Propofol Combined With Remifentanil On Evoked Potential Monitoing Under Partial Neuromuscular Blockade During Brainstem Surgery

Objective: This article had observed the effects of low-dose sevoflurane or propofol combined with remifentanil on transcranical electric motor-evoked potentials and somatosensory-evoked potentials monitoring during brainstem tumor surgery under the same degree of depth of anesthesia and partial neuromuscular block,we are aimed at providing an optional anesthetic method for neurosurgery operations.Methods: Forty cases of consecutive patients,ASA ? or ? level,undergoing brainstem tumor surgery were randomly divided into 2 groups,sevoflurane group?Group S,sevoflurane inhalation anesthesia,receive sevoflurane inhalation and keep the end-tide concentration of sevoflurane remain 0.65MAC?and propofol group?Group P,propofol intravenous anesthesia,continual propofol infusion at rate of 4⁸mg/kg/h?.All cases received remifentanil?0.15⁰.30?g/kg/min?and cisatracurium?0.5¹.5?g/kg/min?,change the infusion rate of drugs to maintain the NTI range from 30 to 45,single twitch stimulation T₁ near 20% of control values or maintain 2 train-of-four stimulation?TOF?counts.We choose abductor pollicis brevis?APB?on upper limbs and tibialis anterior?TA?on lower limbs to record MEPs and stimulated the median nerve and posterior tibial nerve to monitor SEPs.Record the mean atrial pressure?MAP??heart rate?HR??partial pressure of carbon dioxide in end-tide gas?PETCO2?? nasopharynx temperature?T?? NTI ? the amplitude??V?and latency?ms?,infusion rate of cisatracurium??g/kg/min??remifentanil??g/kg/min?and whether the unexpected movement and awareness have occurred or not during the surgery.Result: In group S,the amplitude are lower and the latency is longer than group P at T₁?T₂?T₃ and T₄?P<0.05?,but there were no differences between two groups on SEPs when we stimulate the same nerve.All cases has monitored distinct evoked potentials waveforms.Compared with group P,the infusion rate of cisatracurium is fewer under the same degree of neuromuscular block?P<0.05?,the infusion rate of remifentanil between two groups were no significant difference.No unexpected movement and awareness occurred in all patients during operations.Conclusion: 1.The intraoperative neurophysical monitoring is available under partial neuromuscular blockade?T₁/Tc=20% or Train of Four counts 2?.2.Low-dose?0.65MAC?sevoflurane or propofol combined remifentanil can be safely applied to the monitoring of evoked potentials in brainstem tumor surgery under the same depth of anesthesia and compared partial neuromuscular blockade.