Robertson D R, Swinburn C R, Stone T N, Gibson G J
Department of Respiratory Medicine, Freeman Hospital, Newcastle upon Tyne.
Thorax. 1989 Jun;44(6):461-8. doi: 10.1136/thx.44.6.461.
To determine how the presence of generalised airflow limitation due to chronic obstructive lung disease affects the recognition of simulated upper airway obstruction, a study was carried out in 12 patients (mean (SD) age 57 (7) years) with chronic obstructive lung disease (FEV1% predicted 53 (22), range 21-70) and 12 matched control subjects. Patients and control subjects performed maximal inspiratory and expiratory flow-volume curves in a variable volume plethysmograph with and without upper airway obstruction simulated at the mouth with a series of polythene washers of internal diameter 4, 6, 8, 10, and 12 mm. In patients, as in normal subjects, peak expiratory flow (PEF) and maximum inspiratory flow at 50% of vital capacity (Vmax50) were more sensitive to upper airway obstruction than were FEV1 or maximum expiratory flow at 50% VC (VEmax50); but the reductions in all indices caused by simulated upper airway obstruction were smaller in the patients than in the controls. The fall in PEF (whether expressed in absolute units or as a percentages) consequent on severe (4 mm) upper airway obstruction became smaller with increasing severity of chronic obstructive lung disease. The subjects also produced flow-volume curves with and without 6 mm upper airway obstruction while breathing helium and oxygen (heliox). In both groups the effects of heliox on PEF and Vmax50 were increased when upper airway obstruction was simulated. It was confirmed that the functional recognition of upper airway obstruction is more difficult in patients with chronic obstructive lung disease than in normal subjects and this difficulty increases with severity of disease; an unusually large increase in PEF or Vmax50 while the patient is breathing heliox should raise the suspicion of coexisting upper airway obstruction, but such a pattern is not specific.
为了确定慢性阻塞性肺疾病所致的广泛性气流受限如何影响对模拟上气道梗阻的识别，对12例慢性阻塞性肺疾病患者（平均（标准差）年龄57（7）岁）和12例匹配的对照者进行了一项研究。患者的预计第一秒用力呼气容积（FEV1%）为53（22），范围为21 - 70。患者和对照者在可变容积肺量计中进行最大吸气和呼气流量-容积曲线测定，在口部用一系列内径为4、6、8、10和12 mm的聚乙烯垫圈模拟有无上气道梗阻的情况。与正常受试者一样，患者的呼气峰值流速（PEF）和肺活量50%时的最大吸气流量（Vmax50）对上气道梗阻比第一秒用力呼气容积（FEV1）或肺活量50%时的最大呼气流量（VEmax50）更敏感；但模拟上气道梗阻导致的所有指标下降在患者中比在对照者中更小。随着慢性阻塞性肺疾病严重程度的增加，因严重（4 mm）上气道梗阻导致的PEF下降（无论是以绝对值还是百分比表示）变得更小。受试者在吸入氦氧混合气（heliox）时，还分别测定了有无6 mm上气道梗阻时的流量-容积曲线。在两组中，模拟上气道梗阻时，氦氧混合气对PEF和Vmax50的影响均增强。证实慢性阻塞性肺疾病患者对上气道梗阻的功能识别比正常受试者更困难，且这种困难随疾病严重程度增加而加重；患者吸入氦氧混合气时PEF或Vmax50异常大幅增加应引起对上气道梗阻并存的怀疑，但这种模式并不具有特异性。
