Appendini L, Molina G, Senis L, Garbagni L
Istituto di Medicina Interna, Università degli Studi di Torino, Italia.
Respiration. 1991;58(1):42-8. doi: 10.1159/000195895.
Ventilatory function tests, ventilatory cycle analysis, mouth occlusion pressure (P0.1) and effective inspiratory impedance (P0.1/Vt/Ti) were measured in 11 healthy subjects and in 26 patients with chronic obstructive pulmonary disease (COPD). In COPD patients these measurements were repeated 20 min after inhalation of 400 micrograms of fenoterol. In patients we observed an increase of mean inspiratory flow (Vt/Ti), and a decrease of inspiratory time (Ti) and inspiratory duty cycle (Ti/Ttot). P0.1 and effective inspiratory impedance were significantly increased. Moreover, we found a direct correlation between forced expiratory volume in 1 s (FEV1) and ventilatory cycle components (Ti/Ttot, Ti) and an indirect correlation between FEV1 and Vt/Ti.P0.1 was directly correlated with Vt/Ti and indirectly correlated with ventilatory cycle components. These observations lead us to speculate on the possible role of two opposite mechanisms acting on the control of breathing of COPD patients. While the 'intensity' component of the ventilatory cycle would be set to maintain the tidal volume at a constant level, the 'timing' component would act in order to prevent inspiratory muscle fatigue. Furthermore, in patients responsive to beta 2-agonist drugs, fenoterol inhalation would act in synergy with the timing component of ventilatory cycle, lowering P0.1 and the effective inspiratory impedance.
对11名健康受试者和26名慢性阻塞性肺疾病（COPD）患者进行了通气功能测试、通气周期分析、口腔阻断压（P0.1）和有效吸气阻抗（P0.1/Vt/Ti）测量。在COPD患者中，吸入400微克非诺特罗20分钟后重复这些测量。在患者中，我们观察到平均吸气流量（Vt/Ti）增加，吸气时间（Ti）和吸气占空比（Ti/Ttot）降低。P0.1和有效吸气阻抗显著增加。此外，我们发现第1秒用力呼气量（FEV1）与通气周期成分（Ti/Ttot、Ti）之间存在直接相关性，FEV1与Vt/Ti之间存在间接相关性。P0.1与Vt/Ti直接相关，与通气周期成分间接相关。这些观察结果使我们推测，两种相反的机制可能在COPD患者呼吸控制中起作用。通气周期的“强度”成分将被设定以维持潮气量在恒定水平，而“时间”成分将起作用以防止吸气肌疲劳。此外，在对β2激动剂药物有反应的患者中，吸入非诺特罗将与通气周期的时间成分协同作用，降低P0.1和有效吸气阻抗。
