Tidal volume

TLC	Total lung capacity: the volume in the lungs at maximal inflation
RV	Residual volume: the volume of air remaining in the lungs after a maximal exhalation
ERV	Expiratory reserve volume: the maximal volume of air that can be exhaled from the end-expiratory position
IRV	Inspiratory reserve volume: the maximal volume that can be inhaled from the end-inspiratory level
IC	Inspiratory capacity: the sum of IRV and TV
IVC	Inspiratory vital capacity: the maximum volume of air inhaled from the point of maximum expiration
VC	Vital capacity: the volume equal to TLC − RV
VT	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 VT or VT is used.)
FRC	Functional residual capacity: the volume in the lungs at the end-expiratory position
RV/TLC%	Residual volume expressed as percent of TLC
VA	Alveolar gas volume
VL	Actual volume of the lung including the volume of the conducting airway.
FVC	Forced vital capacity: the determination of the vital capacity from a maximally forced expiratory effort
FEV1	Volume that has been exhaled at the end of the first second of forced expiration
FEFx	Forced expiratory flow related to some portion of the FVC curve; modifiers refer to amount of FVC already exhaled
FEFmax	The maximum instantaneous flow achieved during a FVC maneuver
FIF	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 FIFmax. Unless otherwise specified, volume qualifiers indicate the volume inspired from RV at the point of measurement.)
PEF	The highest forced expiratory flow measured with a peak flow meter
MVV	Maximal voluntary ventilation: volume of air expired in a specified period during repetitive maximal effort

Tidal volume is the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied. Typical values are around 500ml or 7ml/kg bodyweight.

Mechanical Ventilation

The volume of gas moved during the respiratory cycle in mechanical ventilation where control (or at least appreciation) of tidal volume is necessary to ensure adequate ventilation without causing barotrauma. Measurement can be affected (usually over-estimated) by leaks in the breathing circuit or the introduction of additional gas, for example during the introduction of nebulized drugs.

Acute Respiratory Distress Syndrome

There is evidence that limiting tidal volume to below 6ml/kg may be beneficial in the management of ARDS.

External links

• Ricard JD (May 2003). "Are we really reducing tidal volume--and should we?". Am. J. Respir. Crit. Care Med. 167 (10): 1297–8. doi:10.1164/rccm.2303003. PMID 12738592. http://ajrccm.atsjournals.org/cgi/pmidlookup?view=long&pmid=12738592.