Overview Pulmonary Function Tests Metrics Definition OBSTRUCTIVE RESTRICTIVE Elasticity ease of recoil after they have expanded decreased increased Compliance ease of aveloi expanding increase decrease Volumes Minute Volume ventilation rate/min X times tidal volume Residual volume (RV) air left in lung after max expiration increased decreased Total lung capacity (TLC) increased decreased Tidal volume decreased decreased Vital capacity total volume exhaled after full inspiration. decreased decreased Spirometry Forced expiratory volume (FEV1) nl 4L volume expelled in one second decreased decreased Forced vital capacity (FVC) nl 5L entire volume that can be expelled decreased (FEV)/FVC nl 80% considered best screen, values of less than 50% correlate with postoperative pulmonary complications. decreased to 66% increases to 100% Summary Reduced FEV FEV/FVC less than 75% Increased residual volume from air trapping Combination of low FVC low FEV low total lung capacity