Lung Volumes and Capacities PDF
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Gulf Medical University
Dr. Sovan Bagchi
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Summary
This document details lung volumes and capacities, including essential concepts like tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume. It also discusses various lung capacities, such as inspiratory capacity, vital capacity, functional residual capacity, and total lung capacity. Furthermore, it touches upon spirometry and expiratory flow rate.
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Lung Volumes and Capacities Dr. Sovan Bagchi Professor of Physiology www.gmu.ac.ae COLLEGE OF HEALTH SCIENCES Learning Objectives Describe lung volumes and capacities Explain FEV1 and FVC and stat...
Lung Volumes and Capacities Dr. Sovan Bagchi Professor of Physiology www.gmu.ac.ae COLLEGE OF HEALTH SCIENCES Learning Objectives Describe lung volumes and capacities Explain FEV1 and FVC and state its importance List obstructive and restrictive respiratory diseases Spirometer It records the lung volumes and capacities Lung Volumes and Capacities The total volume in the lung at the end of a maximal inspiration is subdivided into volumes and capacities. Lungs Volumes and Capacities Lungs Volumes 1. Tidal volume (TV) 2. Inspiratory Reserve volume (IRV) 3. Expiratory Reserve volume (ERV) 4. Residual volume ( RV ) Lungs Volumes 1. Tidal Volume (TV) It is the amount of air breathed in or out in a quiet respiration. Its value is 500 ml 2. Inspiratory Reserve Volume (IRV) It is the amount of air that can be maximally inspired by a forced inspiration after a normal inspiration. Its value is 3000 ml 3. Expiratory Reserve Volume (ERV) It is the amount of air that can be maximally expired from the end of normal expiration. Its value is 1100 ml Lungs Volumes 4. Residual Volume (RV) It is the amount of air that remains in the lungs after a maximal expiration. Its value is 1200 ml Residual volume is increased in old age, emphysema Lung Capacities Sum of one or two volumes = Capacities 1. Inspiratory capacity (TV + IRV ) 2. Vital capacity (TV+IRV+ERV) 3. Functional residual capacity (RV+ERV) 4. Total lung capacity (TV+IRV+ERV+RV ) Lung Capacities 1. Inspiratory capacity (TV + IRV ) Maximum volume of air that can be inspired by forced inspiration after a normal expiration. Normal Value: 3500 ml 2. Vital capacity (VC ) (TV+IRV+ERV) Maximum volume of air that can be forcefully expelled from the lungs following a maximum inspiration. Normal Value: 4600 ml 3. Functional residual capacity (FRC ) (RV+ERV ) Volume of air remaining in the lungs at the end of a normal expiration. Normal value: 2300ml 4. Total lung capacity (TV+IRV+ERV+RV ) Volume of air contained in the lungs at the end of a maximal inspiration. Normal Value: 6000ml Expiratory Flow Rate It is also known as peak expiratory flow rate (PEFR). It is recorded by using peak flow meter. The subject expires maximally for 10 msec into the flow meter through the mouth and the value is expressed for 1 minute. Normal value is 400 L/ minute PEFR measure air flow obstruction in larger airways (asthma) Forced Vital Capacity FVC Total volume of air that can be exhaled forcefully from TLC The majority of FVC can be exhaled in
