Pulmonary Function Tests Other tests of lung function:1. Lung mechanics -Resistance -Compliance 2. Distribution of Ventilation (N2 delta) 3. Maximal Respiratory Pressures (MIP, MEP) V/Q ratio V/Q mismatch (3-compartment model) Lung volumes and capacities How to measure FRC (RV,TLC) ? Nitrogen washout method Inert gas dilution technique Plethysmography Resistance Volume dependence of airway resistance (Raw) S Raw (cmH 2 O/L/sec) Lung Volume (liters) TLC RV Compliance Ventilatory Mechanics: Healthy P cw P RS PLPL % VC Pressure (cmH 2 O) Ventilatory Mechanics: Healthy % VC Pressure (cmH 2 O) resistive WOB P VP V S Raw as lung volume because the airways distend as the lungs inflate, and bigger airways have lower resistance (*Poiseuilles Law*). The opposite is also true, of course! S Raw (cmH 2 O/L/sec) Lung Volume (liters) TLC RV P V elastic WOB P V elastic and resistive work of breathing is minimized when tidal breathing occurs within the compliant portion of the respiratory systems P-V curve VTVT IC Begin Exercise IC Ventilatory Mechanics: Healthy TLC RVRV Volume (liters) Pressure (cmH 2 0) EELV Ventilatory Mechanics: Healthy EILV IRV IC VTVT EELV IRV Dynamic hyperinflation during exercise Diffusion capacity (DLCO, DLCO/VA, Tco, Kco) Mechanism of hypoxaemia Hypoxaemia, hypercapnia in clinical cases acute chronic Respiratory and metabolic shifts acute chronic Exercise tests in lung diseases 1.Exercise-induced asthma (EIA) - FEV1 2.Interstitial lung disease (ILD) - SAT 3.Exercise tolerance in rehabilitation (COPD) - cardiopulmonary exercise (CPX). Important variables: - work rate (watts), SpO2, ABG - VO2, VCO2, RQ, VE - lactate threshold (LT) - breathing reserve (1-VEmax/MVV) - heart rate reserve (1-HRmax/220-age) Mechanism of exercise-induced hypoxaemia Noninvasive determination of lactate threshold by the V-slope method Exercise training 1. Endurance leg, arm -Wmax % min, 3x/weeek 2. Strength -max. weight 80% - 8 repetitions, 3 series - 3x/week 3. Respiratory muscle - selected cases (reduced breathing reserve) - Mller manouver, >PImax 30% Respiration during exercise ( Wasserman K, 1999 )