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Explore the history of spirometry, from John Hutchinson in 1846 to modern ventilation tests. Learn about lung volumes, diseases like asthma and COPD, pulmonary function metrics, exercise tests, and diagnostic methods. Master the essentials of spirometry technique and interpretation in health and disease.
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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