Closing Capacity to Total Lung Volume Capacity
Info
Inspiratory Reserve Volume
unit Liters ml
Tidal Volume
unit Liters ml
Expiratory Reserve Volume
unit Liters ml
Residual Volume
unit Liters ml
Closing Volume
unit Liters ml
R e s u l t s
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Total Lung Volume Capacity
 
Closing Capacity
 
Ratio of closing capacity to Total Lung Volume Capacity
 
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Info
Closing Capacity to Total Lung Volume Capacity
  • Total Lung Capacity (TLC) is the volume of air in the lungs at the end of maximal inspiration
  • The closing capacity (CC) is the volume in the lungs at which the alveoli collapse
  • The ratio of closing capacity to Total Lung Volume Capacity appears to correlate with asthma severity and is also altered in healthy smokers

The formulas utilized in this calculation include:

  • TLC=IRV+TV+ERV+RV
  • CC=CV+RV
  • CC/TLC(%)=100*CC/TLC

Data the user will need (all items in liters):

  • IRV
  • TV
  • ERV
  • RV
  • CV

Abbreviations used:

  • TLC=Total lung capacity
  • CC=Closing capacity
  • IRV=Inspiratory Reserve Volume
  • TV=Tidal Volume
  • ERV=Expiratory Reserve Volume
  • RV=Residual Volume
  • CV=Closing Volume

Interpretation:

One study by Van Veen, et al., found that CC/TLC increased with severity of asthma. In their trial they found mean CC/TLC % of:

  • Mild-Moderate Asthma: 39.7
  • Severe Asthma no oral steroids: 40.3
  • Severe Asthma on oral steroids: 53.8

Another study by Bourdin, et al., found CC/TLC to be significantly higher in asthmatic patients. Harrison, et al., found differences in young healthy cigarette smokers of elevated CC/TLC. Lapperre, et al., found a significant correlation in COPD patients between CC/TLC and BAL neutrophil numbers.

References:

  • Bode FR, Dosman J, Martin RR, et al. Age and sex differences in lung elasticity, and in closing capacity in nonsmokers. J Appl Physiol. 1976;41(2):129-35.
  • Bourdin A, Paganin F, Préfaut C, et al. Nitrogen washout slope in poorly controlled asthma. Allergy. 2006;61(1):85-9.
  • Harrison GN, Mohler JL, Lewis LA, et al. Peripheral airway function in healthy young cigarette smokers. Lung. 1979;156(3):205-15.
  • Lapperre TS, Willems LN, Timens W, et al. Small airways dysfunction and neutrophilic inflammation in bronchial biopsies and BAL in COPD. Chest. 2007;131(1):53-9.
  • Van veen IH, Sterk PJ, Schot R, et al. Alveolar nitric oxide versus measures of peripheral airway dysfunction in severe asthma. Eur Respir J. 2006;27(5):951-6.
  • In't veen JC, Beekman AJ, Bel EH, et al. Recurrent exacerbations in severe asthma are associated with enhanced airway closure during stable episodes. Am J Respir Crit Care Med. 2000;161(6):1902-6.
  • Wahba WM. Influence of aging on lung function--clinical significance of changes from age twenty. Anesth Analg. 1983;62(8):764-76.