急性CO_2潴留及西地兰对犬膈肌作用观察

Effects of acute hypercapnia and cedilanid on diaphragmatic functions in dogs

用电刺激犬膈肌神经、记录经膈压(Pdi)-刺激频率(F)曲线及膈肌单收缩指标,分析自主呼吸肌电频谱(EMGdi)的方法,研究急性CO_2潴留对膈肌功能的影响,探讨pH、运动在其中的作用,观察西地兰在急性CO_2潴留时对膈肌疲劳的预防作用。发现:(1)急性CO_2潴留严重损害膈肌功能。(2)pH下降是膈肌疲劳的重要原因。(3)静止的膈肌可减轻CO_2潴留的损害。(4)西地兰对急性CO_2潴留所致的膈肌疲劳有一定预防作用。

After electrical stimulation of the phrenic nerve,the function of the diaphragm was assessed by measurement of the transdiaphragmatic pressure (PDi),establishment of the Pdi-sti-mulating frequency (F) curve,and analysis of the power spectrum on the diaphragmatic elec-tromyogram (EMGdi) at spontaneous breathing.Hypercapnia of the dogs was induced by forcing the animals to inhale a mixture of CO2 and air.The findings were as follows:(1) After acute hypercapnia,PDi rapidly and progressively decreased.The power spectrum of EMGdi was also reduced.The PDi-F curve was shifted to right.These findings suggest that the function of the diaphragm was severely damaged.(2) The decrease of pH value was the important cause of diaphragmatic fatigue.(3) The diaphragm in a static condition could reduce the damage of hypercapnia.(4) Cedi-lanid exerted certain effects on the prevention of diaphragmatic fatigue created by acute hypercapnia.