PURPOSE: Pulmonary function tests including the single-breath diffusing capacity of the lung (DLCO) and measurement of oxygen saturation by pulse oximetry (SpO2) are well-recognized tools for assessing pulmonary disease. The purpose of this study was to determine in patients with FEV1<50%, response of DLCO and SpO2 to a short acting inhaled β2-agonist.
METHODS: Patients referred for spirometry with FEV1 ≤; 50% underwent baseline measurement of DLCO and SpO2. Lung function tests and pulse oximetry were repeated within fifteen minutes of 400 μg of inhaled salbutamol administration. This study was carried out over a 3- month- period in a University Hospital-based pulmonary function laboratory.
RESULTS: A total of 38 consecutive patients were assessed. According to ATS/ ERS guidelines 30 patients had severe obstructive disease (FEV1: 34–50%) and 8 had very severe obstructive disease (FEV1 ≤; 34%). The mean variation between the two measurements was an increase of 14,6% (169 ml) for FEV1, 4% for DLCO and 0, 6% for SpO2. The coefficient of correlation between baseline FEV1 and DLCO was 52% which increased to 77% post bronchodilation.Other patient factors such as gender and age were not associated with measurement variability.
CONCLUSION: A positive correlation between baseline DLCO and post bronchodilation was found even though the mean variation increase was low. The coefficient of correlation between FEV1 and DLCO increased significantly after bronchodilation.
CLINICAL IMPLICATIONS: In patients with severe COPD there seems to be a positive response of DLCO to a short acting inhaled β2-agonist. However, there is no significance in clinical testing of SpO2 response to bronchodilation.
DISCLOSURE: Jessica Cemlyn-Jones, No Financial Disclosure Information; No Product/Research Disclosure Information