Transcutaneous monitoring and response to handgrip exercise.

1218 Communications to the Editor The question raised here was: “Did this patient have emphysema or not?” If he merely had bronchial asthma, was he a candidate for antitrypsin replacement therapy? We were confused by the normality of this patient’s Dlco measurements since we had believed that the diffusion capacity was probably the most sensitive indication ofemphysema in the appropriate clinical setting. We undertook to investigate the likelihood ofemphysema in this patient by performing tests of compliance and a CT scan of his lungs. These test results showed that the patient most likely had pulmonary emphysema despite the normal Dco. His static lung compliance was abnormally high at 0.45 (predicted 0.20 ±0.035, performed by the static deflation method from total lung capacity with compliance measured 1 L above functional residual capacity9, and the maximum negative pressure was abnormal at 12.5 (predicted 34.8 ±8.22). CT scan showed hyperinflation with discrete blebs consistent with early emphysema (Fig 1). From this experience we learned that some patients may have a diagnosis of pulmonary emphysema in the presence of a normal Dco. There may be a stage in the development of emphysema where the alveolar surface area and capillary blood volume appear to be substantially preserved, causing a normal diffusion test, but the elasticity and localized structure of the lungs are impaired.