Effect of propofol dose changes on intraoperative somatosensory and motor evoked potentials monitoring

Abstract

Objectives:To investigate the effect of propofol dose changes on somatosensory evoked potential(SEP) and motor evoked potential(MEP).Methods:Twenty patients with idiopathic scoliosis received surgical treatment with propofol intravenous anaesthesia,and multimodality intraoperative neurophysiologic monitoring was reviewed.The changes of SEP and MEP in responding to dose increase were recorded during induction of anaesthesia,and the changes in responding to dose decrease were recorded during closure procedure.Dose-increase delay and dose-decrease delay periods were measured accordingly.Results:The change of propofol dose did not produce significant change in latency of SEP(36.1 ±2.6ms vs 36.2±2.3ms,P>0.05) and MEP(27.0±1.5ms vs 27.1±1.6ms,P>0.05).The increase of propofol dose significantly decreased the amplitude of SEP(1.91±0.53μV vs 1.37±0.55μV,P<0.001) and MEP(175.7±134μV vs 127±81μV,P<0.001),while the decrease of propofol dose significantly increased the amplitude of SEP(1.26 ±0.64μV vs 1.50±0.56μV,P<0.005) and MEP(143 ± 100μV vs 169 ± 133μV,P <0.005).However,there was lag effect of SEP and MEP changes in responding to dose change of propofol.The dose-increase delay period was 18.5 ±6.5min in SEP and 10.5±3.6min in MEP respectively,while dose-decrease delay period was 29.6±10.6min in SEP and 13.5±6.3min in MEP respectively,there were statistically differences between two groups(P<0.05).Conclusions:The dose of propofol increase may produce a faster decrease of SEP and MEP.On the contrary,the dose decrease will cause a increase of SEP and MEP.In addition,MEP is more sensitive to dose changes of anesthetic than SEP.

目的:探討異丙酚濃度變化對體感誘發電位(SEP)和運動誘發電位(MEP)的影響。方法:20例接受手術治療的特發性脊柱側凸患者,術中實施異丙酚靜脈全麻和多模態神經電生理監護。在麻醉誘導期間,觀察SEP、MEP隨異丙酚濃度增加的變化。在矯形操作完成后的傷口縫合過程中,觀察SEP、MEP隨麻醉濃度降低的變化。分別記錄相應異丙酚劑量增加和劑量減少后電位達到平臺期的延遲時間。結果:異丙酚濃度的變化不會引起SEP和MEP潛伏期的顯著變化(SEP:36.1±2.6ms vs 36.2±2.3ms,P>0.05;MEP:27.0±1.5ms vs 27.1±1.6ms,P>0.05)。異丙酚濃度的增加可以顯著降低SEP波幅值(1.91±0.53μV vs 1.37±0.55μV,P<0.001)和MEP幅值(175.7±134μV vs 127±81μV,P<0.001);異丙酚濃度降低則顯著增加SEP幅值(1.26±0.64μV vs 1.50±0.56μV,P<0.005)和MEP幅值(143±100μV vs 169±133μV,P<0.005)。SEP、MEP的變化相對于異丙酚劑量變化存在滯后效應。當劑量增加時,延遲期顯示SEP為18.5±6.5min,而MEP為10.5±3.6min;當劑量減少時,延遲期顯示SEP為29.6±10.6min,而MEP為13.5±6.3min,兩組間比較差異有顯著統計學意義(P<0.05)。結論:異丙酚劑量升高可造成SEP和MEP幅值的快速下降,劑量降低可使其峰值增加;MEP較SEP對異丙酚劑量變化更為敏感。