lung volumes


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lung volumes

Physiology A group of air 'compartments' into which the lung may be functionally divided
Lung volumes  
Expiratory reserve capacity–ERV The maximum volume of air that can be voluntarily exhaled
Functional residual capacity (FRV) Volume left in the lungs at the end of a normal breath which is not normally part of the subdivisions
Inspiratory capacity–IC The maximum volume that can be inhaled
Inspiratory Reserve capacity–IRC The maximum volume that can be inhaled above the tidal volume
Tidal volume–VT The normal to-and-fro respiratory exchange of 500 cc; vital capacity is the maximum amount of exhalable air; after a full inspiration, which added to the residual volume, is the total lung capacity
Total lung capacity–TLC The entire volume of the lung, circa 5 liters
Vital capacity–VC The maximum volume that can be inhaled and exhaled  
Lung volumes.

lung volumes

measurements made as part of pulmonary function tests; the volumes that move in and out during the normal breathing cycle, and with deliberate additional effort, can be measured directly by spirometry with the subject breathing through a closed circuit in and out of a cylinder inverted over water, or into a vitalograph, or by pneumotachograph; the residual volume can be measured only indirectly by dilution methods (usually with helium) or by whole body plethysmography. See also ventilation. See figure and table overleaf .
Table 1: Lung volumes
VT (TV)Tidal volumeVolume of inspired/expired air moving in and out with each breath
IRV
ERV
Inspiratory and expiratory reserve volumesUsed when tidal volume increases above that at rest
VCVital capacityVolume that can be inspired/expired after full expiration/inspiration
FEV1Forced expiratory volume in 1sVolume exhaled in the first second, with maximal effort after full inspiration
FRCFunctional residual capacityVolume remaining in the lungs at end-expiration; decreases as tidal volume increases
RVResidual volumeRemains after a maximal expiratory effort; cannot be exhaled
TLCTotal lung capacityVital capacity + residual volume
References in periodicals archive ?
Although family physicians rarely perform spirometry or measure lung volumes in the clinic, it is important to highlight that spirometry assessment is conducted by some primary care practitioners, and should be utilized more readily in primary care to provide reinforcement of diagnoses.
They showed 50% reduction in MVV and attributed this to decreased lung volumes, fixed thoracic cage, and loss of musculoskeletal power which are characteristics of scoliosis.
3]/FVC may be used to assess the presence of hyperinflation and air trapping, especially in settings where the lung volumes cannot be measured.
Table-2: Adjusted logistic regression analysis of respiratory symptoms with impaired percentage predicted lung volume among textile workers (n=372).
The major types of pulmonary function tests include spirometry, measurement of lung volume and quantitation of diffusing capacity.
Despite the lung volumes remain within the normal range on light-to-moderate obesity, some former studies report that in obese individuals the weight loss leads to improvement on lung volumes [24,25].
Another possible theory is that the increase in end-expiratory lung volume, which may lead to increased transmural pressure gradients, may be associated with better UA patency.
Changing relationships between stature and lung volumes during puberty.
Lung volumes and maximal respiratory pressures in collegiate swimmers and runners.
Conclusion: Smoking was related to decline in respiratory muscle strength, lung volumes and airflow obstruction as well.
Figure 2 puts the relaxation pressure curve in the context of some of the lung volumes and capacities previously defined.
Some investigators have proposed that the deep inspiratory maneuvers practiced by marijuana smokers could stretch the lungs, resulting in larger lung volumes.