EVALUATION OF PERIPHERAL AIRWAY RESISTANCE IN ASTHMA

我们已经表明，夜间哮喘（NA）与实质炎症增加有关；然而，炎症是否导致远端肺功能改变尚不清楚。因此，我们研究了10例NA， 4例非夜间哮喘（NNA）和4例非哮喘对照(C)。他们分别在下午4点和凌晨4点随机进行了肺功能检查，随后进行了食管球囊放置和支气管镜检查。将支气管镜楔入右下叶前段，随后插入5号导管。热的、饱和的空气以100 ml/min-1000 ml/min的流速从一个管腔流出导管，并通过第二个管腔测量压力。阻力（Rp）定义为每个受试者在三个或更多流量水平上的压力/流量平均值。在功能剩余容量时停止流动，并允许压力衰减10秒；以总衰减量的63% （1/e）的时间定义为时间常数（TC）。依从性（Compl）以TC/Rp计算。与NNA和C相比，NA组的Rp显著高于前者（上午4点p=0.002，下午4点p= 0.003），依从性显著低于后者（上午4点p=0.02，下午4点p= 0.003）（见表）。Rp组4 am Rp 4pm Compl 4 am Compl 4pm (cm H20/ml/min) (cm H20/ml/min) （ml/cm H20) (ml/cm H20) C 0.009 [0.006-0.011] 0.011 [0.001-0.013] 454 [205-705] 280 [141-522] NNA 0.035 [0.022-0.048] 0.035 [0.022-0.048] 57 [21-154] 71 [32-126] NNA 0.124[0.055-0.165] 0.113[0.059-0.200] 10[5.4-14.6] 8[4-19]此外，当与全肺功能相关时，4am: r=0.60, p=0.03; 4pm: 0.71, p=0.004）。另一方面，FEV1和FVC在任何一个时间点都与Rp无关。我们的结论是，这些发现与假设一致，即在哮喘中，炎症活动增加导致进行性实质功能障碍。

We have shown that nocturnal asthma (NA) is associated with increased parenchymal inflammation; however, whether the inflammation results in a functional change in the distal lung is not known. Therefore, we studied 10 subjects with NA, 4 subjects with non-nocturnal asthma (NNA) and 4 nonasthmatic controls (C). They underwent lung function testing followed by esophageal balloon placement and bronchoscopy in a random order at 4 pm and 4 am, respectively. The bronchoscope was wedged in the anterior segment of the right lower lobe followed by insertion of a size 5 French catheter. Warm, saturated air at flows ranging from 100 ml/min-1000 ml/min exited the catheter through one lumen and pressure was measured through the second lumen. Resistance (Rp) was defined as the pressure/flow averaged over three or more flow levels for each subject. Flow was stopped at functional residual capacity and the pressure was allowed to decay for 10 seconds; the time to decay by 63% (1/e) of the total was defined at the time constant (TC). Compliance (Compl) was calculated as TC/Rp. The Rp was significantly higher in NA (p=0.002 at 4 am and 0.003 at 4 pm) and compliance was significantly lower (p=0.02 at 4 am and 0.003 at 4 pm) than NNA and C (see table). Group Rp 4 am Rp 4pm Compl 4 am Compl 4 pm (cm H20/ml/min) (cm H20/ml/min) (ml/cm H20) (ml/cm H20) C 0.009 [0.006-0.011] 0.011 [0.001-0.013] 454 [205-705] 280 [141-522] NNA 0.035 [0.022-0.048] 0.035 [0.022-0.048] 57 [21-154] 71 [32-126] NA 0.124 [0.055-0.165] 0.113 [0.059-0.200] 10 [5.4-14.6] 8 [4-19] In addition, when related to whole lung function, the residual volume correlated with the Rp at both 4 am and 4 pm (4 am: r=0.60, p=0.03; 4 pm: 0.71, p=0.004). On the other hand, FEV1 and FVC did not correlate with the Rp at either time point. We conclude that these findings are consistent with the hypothesis that, in asthma, increased inflammatory activity causes progressive parenchymal dysfunction.