Closing Capacity
Info
Residual Volume
unit Liters ml
Closing Volume
unit Liters ml
R e s u l t s
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Closing Capacity
 
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Info
Closing Capacity
  • The closing capacity (CC) is the volume in the lungs at which the alveoli collapse
  • The closing capacity appears to correlate with asthma severity, hypoxemia, and atelectasis.

The formula utilized in this calculation is:

  • CC=CV+RV

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

  • CV
  • RV

Abbreviations used:

  • CC=Closing capacity
  • RV=Residual Volume
  • CV=Closing Volume

Interpretation:

One study by in't Veen, et al., found that CC increased in the patients with difficult-to-control asthma as compared with the group with stable asthma:

  • Difficult-to-control Asthma: 114.0 ± 6.4
  • Stable Asthma: 99.9 ± 3.6

Bevan et al., found that if the closing capacity (CC) exceeded functional residual capacity (FRC) it can cause hypoxemia in pregnant woman.

Hedenstierna found that Atelectasis can occur in patients where closing capacity (CC) exceeded functional residual capacity (FRC).

Another study by Torchio R, et al., found CC was greater than functional residual capacity [FRC]) in most patients with chronic heart failure (CHF) but was absent in control subjects.

References:

  • Bevan DR, Holdcroft A, Loh L, et al. Closing volume and pregnancy. Br Med J. 1974;1(5896):13-5.
  • Hedenstierna G. Alveolar collapse and closure of airways: regular effects of anaesthesia. Clin Physiol Funct Imaging. 2003;23(3):123-9.
  • 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.
  • Torchio R, Gulotta C, Greco-lucchina P, et al. Closing capacity and gas exchange in chronic heart failure. Chest. 2006;129(5):1330-6.