<Table> <Tr> <Td_colspan="2"> </Td> </Tr> <Tr> <Th> TLC </Th> <Td> Total lung capacity: the volume in the lungs at maximal inflation, the sum of VC and RV . </Td> </Tr> <Tr> <Th> TV </Th> <Td> Tidal volume: that volume of air moved into or out of the lungs during quiet breathing (TV indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol TV or V is used .) </Td> </Tr> <Tr> <Th> RV </Th> <Td> Residual volume: the volume of air remaining in the lungs after a maximal exhalation </Td> </Tr> <Tr> <Th> ERV </Th> <Td> Expiratory reserve volume: the maximal volume of air that can be exhaled from the end - expiratory position </Td> </Tr> <Tr> <Th> IRV </Th> <Td> Inspiratory reserve volume: the maximal volume that can be inhaled from the end - inspiratory level </Td> </Tr> <Tr> <Th> IC </Th> <Td> Inspiratory capacity: the sum of IRV and TV </Td> </Tr> <Tr> <Th> IVC </Th> <Td> Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration </Td> </Tr> <Tr> <Th> VC </Th> <Td> Vital capacity: the volume of air breathed out after the deepest inhalation . </Td> </Tr> <Tr> <Th> V </Th> <Td> Tidal volume: that volume of air moved into or out of the lungs during quiet breathing (VT indicates a subdivision of the lung; when tidal volume is precisely measured, as in gas exchange calculation, the symbol TV or V is used .) </Td> </Tr> <Tr> <Th> FRC </Th> <Td> Functional residual capacity: the volume in the lungs at the end - expiratory position </Td> </Tr> <Tr> <Th> RV / TLC% </Th> <Td> Residual volume expressed as percent of TLC </Td> </Tr> <Tr> <Th> V </Th> <Td> Alveolar gas volume </Td> </Tr> <Tr> <Th> V </Th> <Td> Actual volume of the lung including the volume of the conducting airway . </Td> </Tr> <Tr> <Th> FVC </Th> <Td> Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort </Td> </Tr> <Tr> <Th> FEV </Th> <Td> Forced expiratory volume (time): a generic term indicating the volume of air exhaled under forced conditions in the first t seconds </Td> </Tr> <Tr> <Th> FEV </Th> <Td> Volume that has been exhaled at the end of the first second of forced expiration </Td> </Tr> <Tr> <Th> FEF </Th> <Td> Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled </Td> </Tr> <Tr> <Th> FEF </Th> <Td> The maximum instantaneous flow achieved during a FVC maneuver </Td> </Tr> <Tr> <Th> FIF </Th> <Td> Forced inspiratory flow: (Specific measurement of the forced inspiratory curve is denoted by nomenclature analogous to that for the forced expiratory curve . For example, maximum inspiratory flow is denoted FIF . Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement .) </Td> </Tr> <Tr> <Th> PEF </Th> <Td> Peak expiratory flow: The highest forced expiratory flow measured with a peak flow meter </Td> </Tr> <Tr> <Th> MVV </Th> <Td> Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort </Td> </Tr> <Tr> <Td_colspan="2"> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table> <Tr> <Th> TLC </Th> <Td> Total lung capacity: the volume in the lungs at maximal inflation, the sum of VC and RV . </Td> </Tr>

What is the normal ratio of fev1 fvc