Fujii Yoshitaka
Department of Anesthesiology, Institute of Clinical Medicine, University of Tsukuba, 2-1-1, Amakubo, Tsukuba City, Ibaraki 305-8576, Japan.
Pulm Pharmacol Ther. 2004;17(1):57-60. doi: 10.1016/j.pupt.2003.10.003.
The present study was undertaken to evaluate the efficacy of inhaled milrinone on contractility of fatigued diaphragm in dogs. Animals were divided into four groups of seven each. In each group, diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. Immediately after the end of a fatigue-producing period, Group I received inhaled vehicle; Group II received inhaled milrinone 0.1 mg/ml (1 mg); Group III received inhaled milrinone 0.2 mg/ml (2 mg); Group IV received 0.5 mg/ml (5 mg). Study drug was administered for 30 min. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi). After the fatigue-producing period, in each group, Pdi at low-frequency (20 Hz) decreased from baseline values (P<0.05), and Pdi at high-frequency (100 Hz) stimulation did not change. In Groups III and IV, during milrinone inhalation, Pdi at both stimuli increased from fatigued values (P<0.05). The increase in Pdi was more in Group IV than in Group III (P<0.05). Compared with Group I, Pdi to each stimulus did not change in Group II. In conclusion, inhaled milrinone, in doses more than 0.2 mg/ml, is effective for improving contractility of fatigued diaphragm in dogs.
本研究旨在评估吸入米力农对犬疲劳膈肌收缩力的影响。将动物分为四组，每组七只。每组通过以20Hz的频率进行间歇性双侧超强膈神经电刺激30分钟来诱导膈肌疲劳。在产生疲劳的时间段结束后立即进行如下处理：第一组吸入赋形剂；第二组吸入0.1mg/ml（1mg）的米力农；第三组吸入0.2mg/ml（2mg）的米力农；第四组吸入0.5mg/ml（5mg）的米力农。研究药物给药30分钟。通过跨膈压（Pdi）评估膈肌收缩力。在产生疲劳的时间段后，每组低频（20Hz）时的Pdi均较基线值降低（P<0.05），高频（100Hz）刺激时的Pdi未改变。在第三组和第四组中，吸入米力农期间，两种刺激下的Pdi均较疲劳时的值升高（P<0.05）。第四组Pdi的升高幅度大于第三组（P<0.05）。与第一组相比，第二组中每种刺激下的Pdi均未改变。总之，吸入剂量超过0.2mg/ml的米力农可有效改善犬疲劳膈肌的收缩力。
