Vincent Lopez-Majano

Airway Function in Sarcoidosis: Smokers versus Nonsmokers

Pulmonary function was measured in 24 sarcoidosis patients, 17 nonsmokers and 7 smokers. 12 (4 smokers) had evidence of small airway disease and 6 patients (3 smokers) had evidence of large airway disease. A significantly greater proportion of smokers had an increased closing volume, and closing volume appears to be the most sensitive test for small airway disease in sarcoidosis. However, 3 patients with normal closing volumes had evidence of small airway disease by forced expiratory flow rates or frequency dependence of compliance. We conclude that there is a high incidence of small airway disease in patients with sarcoidosis. There also appears to be a synergism between sarcoidosis and smoking that leads to a significant degree of hyperinflation of the lung.

Airway Function in Sarcoidosis: Effect of Short-Term Steroid Therapy

13 previously untreated patients suffering from early pulmonary sarcoidosis (stages II and III) were studied radiologically and physiologically after 4 months of corticosteroid treatment. The results of airway function studies before and after corticosteroid treatment were compatible with small airway disease that did not improve after treatment. Before steroids, the main abnormalities were decreased diffusion and compliance, increased alveolar-arterial oxygen tension gradients, and the presence of frequency-dependent compliance. After steroids, significant improvement was found in diffusion and alveolar-arterial oxygen tension gradients, but compliance as well as frequency-dependent compliance did not improve.

Early diagnosis of interstitial fibrosis.

2 cases of interstitial fibrosis of the Hamman-Rich type are presented. The patients were symptomatic, but had normal X-rays. They were suspected of having interstitial infiltration by pulmonary function tests. Diagnosis was confirmed by lung biopsy. Pulmonary function tests, especially the study of elastic properties of the lung, can be of primary help in the diagnosis of pulmonary interstitial infiltration and fibrosis when the patients X-ray is normal.

Indications for Pulmonary Function Testing

Pulmonary function testing is needed to determine the pathophysiology present in the patient with cardiopulmonary disease. Blood gases and pH should be obtained during emergency situations and during cranial, thoracic, and extensive cervical or abdominal surgery. Lung function tests can be divided in global such as spirometry and diffusing capacity which study the ventilation and transfer of gases and regional determinations of ventilation and perfusion. Both types of tests complement each other and should be used together. The spirometry should consist at least of determination of the vital capacity and is determined in the first second to ascertain if there is obstructive lung disease. Some tests such as flow-volume curves, alveolar-arterial gradients and closing volume are very useful to detect early pulmonary disease before any symptoms or findings are present. This is probably one of the most important medical indications for pulmonary function testing. Before certain types of surgery pulmonary function testing is indicated; if the spirometry and diffusing capacity tests are normal, there is no pulmonary contraindication for the planned surgery. In chest surgery if there is significant compromise of the spirometry and diffusing capacity regional lung function tests are indicated to study the pathophysiology at regional level, thus trying to circumscribe the lung resection to the diseased areas.

Indications for Lung Scintigraphy

Perfusion and ventilation lung scintigraphy are indicated: (1) for evaluating regional perfusion and ventilation, (2) for establishing a ratio between ventilation and perfusion in different areas of the lung, (3) when chest surgery is planned (especially for mapping out the extent of resection), (4) when surgery of the upper abdomen is to be performed, and (5) when global function studies are compromised. Regional ventilation and perfusion studies are invaluable in the diagnosis of pulmonary thromboembolism in which a perfusion defect is accompanied by well-preserved ventilation in the underperfused area. Regional function tests are indicated for evaluating the distribution of ventilation and pulmonary circulation in practically any chronic pulmonary disease, especially when global function studies, such as spirometry, show significant decreases.