Blackie S P, al-Majed S, Staples C A, Hilliam C, Paré P D
UBC Pulmonary Research Laboratory, St. Paul's Hospital, Vancouver, British Columbia, Canada.
Am Rev Respir Dis. 1990 Jul;142(1):79-83. doi: 10.1164/ajrccm/142.1.79.
An increased TLC has been reported during exacerbations of asthma, but the methods used (helium, dilution, plethysmography) have been subsequently found unreliable in the assessment of lung volumes in patients with obstructive lung disease. To address this problem, we measured TLC (TLC-XR) from posteroanterior and lateral chest roentgenograms obtained during exacerbations (E) of asthma and after recovery (R) using planimetry in 12 asthmatic subjects. At recovery, TLC was also measured by plethysmography or by helium dilution for comparison with the radiographic measurement. The plethysmographic measurements were made with a panting frequency less than 1 Hz to allow for airway obstruction. A chest radiologist also used independent radiologic measurements of hyperinflation (lung height, diaphragmatic arc height, rib counts) to assess lung volumes. Mean FEV1 during E was 1.43 +/- 0.38 L, and significant improvement occurred at R (FEV1 = 2.81 +/- 0.58 L, p less than 0.05). Of the independent radiologic variables measured, only an increase in lung height distinguished the two sets of radiographs. Mean TLC-XR (E) (6.01 +/- 1.62 L) was significantly greater than mean TLC-XR (R) (5.44 +/- 1.17 L, p less than 0.05). TLC measured radiographically at recovery was strongly correlated (r = 0.94) with TLC measured by plethysmography or helium dilution. We conclude that acute reversible increases in TLC do occur during exacerbations of asthma and that these changes are only readily detected by formal planimetry.
据报道，哮喘发作时肺总量（TLC）会增加，但随后发现所使用的方法（氦稀释法、稀释法、体积描记法）在评估阻塞性肺疾病患者的肺容积时并不可靠。为解决这一问题，我们对12名哮喘患者在哮喘发作期（E）和恢复后（R）拍摄的后前位和侧位胸部X线片进行了平面测量，以测量TLC（TLC-XR）。恢复时，还通过体积描记法或氦稀释法测量TLC，以便与X线测量结果进行比较。体积描记法测量时的呼吸频率小于1Hz，以考虑气道阻塞情况。一名胸部放射科医生还使用了独立的放射学测量方法（肺高度、膈肌弧高度、肋骨计数）来评估肺容积。发作期的平均第一秒用力呼气容积（FEV1）为1.43±0.38L，恢复时出现显著改善（FEV1=2.81±0.58L，p<0.05）。在所测量的独立放射学变量中，只有肺高度的增加能区分两组X线片。发作期的平均TLC-XR（6.01±1.62L）显著高于恢复后的平均TLC-XR（5.44±1.17L，p<0.05）。恢复时通过X线测量的TLC与通过体积描记法或氦稀释法测量的TLC高度相关（r=0.94）。我们得出结论，哮喘发作期间TLC确实会出现急性可逆性增加，并且这些变化只有通过正式的平面测量才能容易地检测到。
