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The inventor of spirometer: John Hutchinson (1846). Ventilation and V/Q ratio. Branching of the airways. Static lung volumes. IC. Slow (SVC) and forced (FVC) vital capacity in health and disease. Elastic forces and airway diameter.
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Branching of the airways
Slow (SVC) and forced (FVC) vital capacity in health and disease
Antropometric data determine reference values • Age • Height • Sex • Race
Asthma - reversible airway obstruction spirogram F-V loop FVC: 2.4 (73 ref%) – 3.1 (92 ref%) FEV1: 1.0 (36 ref%) – 1.5 (52 ref%) FEV1/FVC: 42% - 49%
COPD = postbronchodilator FEV1/FVC<70% (irreversible airway obstruction
Lung fibrosis FVC: 75 ref% TLC: 63 ref% FEV1: 78 ref% RV: 57 ref% FEV1/FVC: 87% DLCO: 34 ref%
Heart failure FVC: 55 ref% FEV1: 49 ref% FEV1/FVC: 74%
Typical spirograms and flow-volume loops
Etiology of obstructive and restrictive ventilatory disorders
Pathophysiology of the variable lesion of the major (proximal) airways
Typical F-V loops in cases of lesions of the major airways
Flow-volume loops A:normal, B:obstructive, C:restrictive
Asthma – reversible obtruction healthy asthmatic
COPD (emphysema!!!)
How to measure FRC (RV,TLC) ? • Nitrogen washout method • Inert gas dilution technique • Plethysmography
RV 4 3 2 SRaw (cmH2O/L/sec) 1 TLC 0 2 4 6 8 Lung Volume (liters) Volume dependence of airway resistance (Raw)
Arterial Blood Gas
Respiratory and metabolic shifts chronic acute acute chronic
Exercise tests in lung diseases Exercise-induced asthma (EIA) - FEV1 Interstitial lung disease (ILD)- SAT 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 (decreased contact time)
Noninvasive determination of lactate threshold by the V(entilatory)-slope method