University:
Western Sydney University
Course:
MEDI 2003 | Clinical Sciences 2
Academic year:

2024
Views:

239

Pages:

2
Author:

Mariam A. A.

Pulmonary Function Tests Lung Volumes (Plethysmography) Obstructive: Increased TLC Increased RV Decreased ERV Decreased FVC Decreased FEV1/FVC ratio Restrictive: Decreased TLC Decreased IRV Decreased RV Decreased FVC Normal FEV1/FVC ratio Forced Spirometry FEV1: Forced expiratory volume in 1 second FVC: Forced vital capacity FEV1/FVC: Ratio of FEV1 to FVC Normal: FEV1/FVC >70% Obstructive: FEV1/FVC <70% Restrictive: FEV1/FVC normal, but FVC decreased Bronchodilator/Bronchoconstrictor Testing SABA (Short-Acting Beta-Agonist): Albuterol Levalbuterol Salbutamol Methacholine: Bronchoconstrictor Used in asthma diagnosis FEV1 decreases by >20% DLCO (Diffusion Lung Capacity) Measures gas exchange Decreased in restrictive lung diseases and pulmonary fibrosis Low DLCO with normal lung volumes indicates interstitial lung disease Diagnostic Approach to PFTs FEV1/FVC < 70%: Suggests Obstructive Check TLC/RV/FRC If ↑TLC, ↑RV, ↑FRC: Suggests Obstructive If ↓TLC, ↓RV, ↓FRC: Suggests Restrictive Administer Bronchodilator If >12% ↑ in FEV1: Suggests Asthma If <12% ↑ in FEV1: Suggests COPD Check DLCO If ↓DLCO: Chronic Bronchitis If normal DLCO: Emphysema FEV1/FVC > 70%: Suggests Restrictive Check TLC/RV/FRC If ↓TLC, ↓RV, ↓FRC: Suggests Restrictive Check DLCO If ↓DLCO: Extrinsic Restrictive Disease If normal DLCO: Interstitial Lung Disease