The management of parapneumonic effusions and empyema.

Background: In normal subjects, and patients with obstructive and restrictive lung defects, flows during an FVC manoeuver are higher after a fast inspiration without an end-inspiratory pause as compared to a slow inspiration with an end-inspiratory pause of approximately 5 s (time dependence of FVC). Objective: In the present study, we investigated the influence of these two manoeuvres on PEF and FEV 1 in asthmatic patients during methacholine challenge testing. Methods: Thirteen patients who were positive according to routine (non-standardized) methacholine challenge tests (PD20£1.57 mg) were studied. Their average(SD) lung function data were: FVC%pred=94(15), FEV 1 %pred=76(17) and FEV 1 /FVC%=68(12). The patients performed the two types of FVC manoeuvres in random order before and at the last methacholine dose. Results: Using the standardized FVC manoeuvres (fast before/fast after and slow before/slow after), only 10 patients (77%) had a positive test, while all 13 patients were positive with the routine test. Conclusion: These data indicate that different results can be obtained, if instead of the standardized, the non-standardized manoeuvres during methacholine challenge tests are used. The use of non-standardized FVC manoeuvres may lead to over-, or at least theoretically, to underestimation of patients with bronchial hyperresponsiveness. Therefore, standardization of FVC manoeuvres during airway challenge testing is required. Pneumon 2002, 15(2)168-175.