Respiratory minute volume

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Lungvolumes Updated.png
TLC

Total lung capacity: the volume in the lungs at maximal

inflation, the sum of VC and RV.
TV

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.)
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
ICInspiratory 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 of air breathed out after the

deepest inhalation.
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
VAAlveolar 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
FEVt

Forced expiratory volume (time): a generic term indicating the volume of air exhaled under forced conditions in the first t

seconds
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

Peak expiratory flow: 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
 
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Lungvolumes Updated.png
TLC

Total lung capacity: the volume in the lungs at maximal

inflation, the sum of VC and RV.
TV

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.)
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
ICInspiratory 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 of air breathed out after the

deepest inhalation.
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
VAAlveolar 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
FEVt

Forced expiratory volume (time): a generic term indicating the volume of air exhaled under forced conditions in the first t

seconds
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

Peak expiratory flow: 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

Respiratory minute volume (or minute ventilation or expired minute volume) is the volume of gas inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs per minute. It is an important parameter in respiratory medicine due to its relationship with blood carbon dioxide levels. It can be measured with devices such as a Wright respirometer, or can be calculated from other known respiratory parameters. Note that although its name implies that it is a volume, minute volume is actually a flow (it represents a volume change over time).

Several symbols can be used to represent minute volume. They include:  \dot{V}, MV, and VE.

Determination of minute volume[edit]

Minute volume can either be measured directly or calculated from other known parameters.

Measurement of minute volume[edit]

Minute volume is the amount of gas inhaled or exhaled from a person's lungs in one minute. It can be measured by a Wright respirometer or other device capable of cumulatively measuring gas flow, such as mechanical ventilators.

Calculation of minute volume[edit]

If both tidal volume (VT) and respiratory rate (ƒ or RR) are known, minute volume can be calculated by multiplying the two values. One must also take care to consider the effect of dead space on alveolar ventilation, as seen below in "Relationship to other physiological rates".

 \dot{V} = V_T \times f

Physiological significance of minute volume[edit]

Blood carbon dioxide (PaCO2) levels generally vary inversely with minute volume.[citation needed] For example, a person with increased minute volume (e.g. due to hyperventilation) should demonstrate a lower blood carbon dioxide level. The healthy human body will alter minute volume in an attempt to maintain physiologic homeostasis. A normal minute volume while resting is about 5–8 liters per minute in humans.[citation needed] Minute volume generally decreases when at rest, and increases with exercise. For example, during light activities minute volume may be around 12 litres. Riding a bicycle increases minute ventilation by a factor of 2 to 4 depending on the level of exercise involved. Minute ventilation during moderate exercise may be between 40 and 60 litres per minute.[1] [2]

Hyperventilation is the term for having a minute ventilation higher than physiologically appropriate. Hypoventilation describes a minute volume less than physiologically appropriate.

Relationship to other physiological rates[edit]

Minute volume comprises the sum of alveolar ventilation and dead space ventilation. That is:

 \dot{V} = \dot{V}_A + \dot{V}_D

where  \dot{V}_A is alveolar ventilation, and  \dot{V}_D represents dead space ventilation.

References[edit]

  1. ^ Zuurbier, M., Hoek, G., van den Hazel, P., Brunekreef, B. (2009). "Minute ventilation of cyclists, car and bus passengers: an experimental study.". Environmental Health 8 (48). doi:10.1186/1476-069x-8-48. 
  2. ^ Int Panis, L (2010). "Exposure to particulate matter in traffic: A comparison of cyclists and car passengers". Atmospheric Environment 44: 2263–2270. doi:10.1016/j.atmosenv.2010.04.028. 


External links[edit]