| Co-Investigator(Kenkyū-buntansha) |
SUGIMORI Kunio Chiba Univ., Sch. of Med., Dept. of Anestesiology, 医学部・附属病院, 助手 (20241961)
IDE Tohru Chiba Univ., Sch. of Med., Dept. of Anestesiology, 医学部・附属病院, 助手 (70213022)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1993: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1992: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Di a phragmatic fatigue is an important cause of respiratory failure, and aminophylline may impreve strength in the fatiguing diaphragm. We tested the hypothese that the reduction in diaphragmatic fatigue during aminophylline administration is associated with an imprevement of aerobic metabolism indicated by a low ratio of inorganic phosphate to phosphocreatine (Pi/PCr). Piglets were anesthetized wity pentobarbital sodium and mechanically ventilated via tracheostmy. They were divided into four groups based in administration of saline alone, aminophylline 10 mg/kg, 20 mg/kg, and 40 mg/kg. The diaphragm was paced via phrenic rerve stimulation in the thrax for 25 min with supramaximal voltage, stimulation frequency 30Hz, duty cycle 0.33 and 10 trains /min followed by 10 min recovery time. Thextrengthof the diaphragm was assessed by the transdiaphragmatic pressure (Pdi). An NMR surface coil was positioned on the diaphragm. ATP concentration, intracellular pH (pHi), and Pi/PCr were obtaiced from NMR data. Diaphragmatic bliid fiow (Qdi, radiolabeked microspheres, technique) was also measured. Aminophylline or seline was administerd as a bolus berore pacing, followed by continuous infusion. Measurements were made at rest, every 5 min of pacing and recovery. There was a significant difference inPdi and Pi/PCr between the saline group and aminophylline groups. In contrast, ATP, pHi and Qdi showed the same time course in all groups. The data suggest that the reduction in fatigue during aminophylline administration is associated with impreved aer obic mechanism in the diaphragm.
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