Nava S, Crotti P, Gurrieri G, Fracchia C, Rampulla C
Pneumology Division, Centro Medico di Riabilitazione di Montescano Fondazione Clinica del Lavoro, Pavia, Italy.
Chest. 1992 Jan;101(1):133-40. doi: 10.1378/chest.101.1.133.
The effect of broxaterol, a new beta 2-agonist, on respiratory muscle endurance and strength was studied in a double-blind, placebo-controlled, randomized crossover clinical trial in 16 patients with chronic obstructive pulmonary disease (COPD) with irreversible airway obstruction (FEV1 = 57.1 percent of predicted). One patient withdrew from the study because of acute respiratory exacerbation. Inspiratory muscle strength was assessed by maximal inspiratory pressure (MIP) and endurance time was determined as the length of time a subject could breathe against inspiratory resistance (target mouth pressure = 70 percent of MIP, Ti/Ttot = 0.4). Broxaterol (B) or placebo (P) was given orally for seven days at the dose of 0.5 mg three times a day with a washout period of 72 h between study treatments. Measurements were performed before administration of B or P and 2 h (six patients) or 8 h (nine patients) after the end of each treatment. No significant changes in FEV1 or FRC were observed after B or P suggesting that diaphragmatic length was maintained constant with each treatment. The MIP did not significantly change, while endurance time increased after B in the patients tested at 2 h (from 234.8 +/- 48.1 s to 284.0 +/- 48.0 s, p less than 0.05) and at 8 h (from 187.2 +/- 31.1 s to 258.2 +/- 40.4 s, p less than 0.005). No changes were observed after P. Minute ventilation, airway occlusion pressure (P0.1), integrated electromyographic activities of the diaphragm (Edi), and intercostal parasternals (Eic) (normalized to the value obtained during MIP) showed no change during the endurance run with different treatments. We conclude that in a group of COPD patients with irreversible airway obstruction, B significantly improves respiratory muscle endurance, and that this does not arise as a result of an effect on neuromuscular drive or pulmonary mechanics, but may be mediated by peripheral factors.
在一项双盲、安慰剂对照、随机交叉临床试验中，对16例患有不可逆气道阻塞（FEV1为预测值的57.1%）的慢性阻塞性肺疾病（COPD）患者，研究了新型β2激动剂布地奈德对呼吸肌耐力和力量的影响。一名患者因急性呼吸加重退出研究。吸气肌力量通过最大吸气压力（MIP）评估，耐力时间确定为受试者在对抗吸气阻力呼吸时的时长（目标口腔压力 = MIP的70%，Ti/Ttot = 0.4）。布地奈德（B）或安慰剂（P）以每日三次、每次0.5 mg的剂量口服7天，研究治疗之间的洗脱期为72小时。在给予B或P之前以及每次治疗结束后2小时（6例患者）或8小时（9例患者）进行测量。给予B或P后，FEV1或FRC未观察到显著变化，表明每次治疗时膈肌长度保持恒定。MIP未显著变化，而在2小时测试的患者中给予B后耐力时间增加（从234.8±48.1秒增至284.0±48.0秒，p<0.05），在8小时测试的患者中也增加（从187.2±31.1秒增至258.2±40.4秒，p<0.005）。给予P后未观察到变化。分钟通气量、气道闭塞压力（P0.1）、膈肌（Edi）和肋间胸骨旁肌（Eic）的综合肌电图活动（标准化为MIP期间获得的值）在不同治疗的耐力试验期间未显示变化。我们得出结论，在一组患有不可逆气道阻塞的COPD患者中，布地奈德显著改善呼吸肌耐力，且这并非由对神经肌肉驱动或肺力学的影响所致，而可能由外周因素介导。
