家兔双前肢悬挂致死过程中的电生理研究

目的探讨悬挂体位致窒息死亡的电生理方面的机制。方法成年家兔12只,雌雄不限。随机分为两组:一组监测膈肌肌电图,另一组监测肋间肌肌电图、心电图、脑电图。取仰卧位固定,手术暴露膈肌和肋间肌,引导肌电图;同时引导标准Ⅱ导联心电图和脑电图。然后将家兔固定双前肢悬挂,连续监测实验过程中家兔的心电、脑电、肌电图的变化情况,直至其死亡。结果悬挂末期和悬挂初期相比,膈肌肌电频率下降(P<0.05)、呼吸波持续时间、振幅和面积均有延长或增多(P<0.05)、最大传导速度无变化;肋间肌仅见肌电频率下降(P<0.05);脑电振幅降低(P<0.01)、δ波增多(P<0.01)、β波减少(P<0.05);心电仅见各波形振幅的降低(P<0.01)。膈肌肌电频率的下降最早,脑电频率的下降次之,肋间肌肌电的下降最晚(P<0.01)。结论悬挂体位致窒息死亡的机制的始动因素是呼吸运动受限,并最终形成外周性呼吸肌疲劳和呼吸中枢缺氧性衰竭而发生死亡。

An electrophysiological study on deaths by anterior limb suspension in rabbits

Objective To investigate the electrophysiological mechanisms in deaths from asphyxia by anterior limb suspension.Methods 12 rabbits of either sex were randomly divided into two groups.In group 1,electromyogram of the diaphragma(EMGD) was monitored,and in group 2,electromyogram of the intercostal muscles(EMGIM),electroencephalogram(EEG) and electrocardiogram(ECG).Briefly,the standard Ⅱ lead ECG,EEG,and EMGD and EMGIM were connected by surgery after the rabbits were fixed at supine position.The rabbits were suspended by anterior limbs with continuously monitoring the ECG,EEG and EMG until the rabbits expired.Results As compared the corresponding data in the end phase of suspension,in the initial phase frequency of EMGD was decreased(P<0.05),duration of respiratory wave was extended(P<0.05) with the amplitude and the area increased(P<0.05).In intercostal muscles,only frequency was reduced(P<0.05).In EEG,the amplitude was decreased(P<0.01),and δ wave was dramatically increased(P<0.01) while β wave decreased(P<0.05).In ECG, only the electrical wave amplitude was significantly reduce(P<0.01).In the course of suspension,the frequency of EMGD was reduced earliest,followed by the frequency of ECG and the frequency of EMGIM(P<0.01).Conclusion The precipitaing factor for the death in the suspension by the anterior limbs in rabbits is associated with the restricted respiratory movement,which may ultimately cause death by the fatigue of periphery respiratory muscles and respiratory failure in the central nervous system.