A comparison of single breath and re-breathe diffusing capacity in emphysema patients and controls

Respir Physiol Neurobiol. 2012 Jul 31;183(1):15-9. doi: 10.1016/j.resp.2012.05.009. Epub 2012 May 24.


In emphysema patients, gas dilutional alveolar volume is underestimated by a 10s single breath maneuver at total lung capacity (TLC) compared with re-breathing at functional residual capacity (FRC); corresponding underestimation of single breath diffusing capacity (DLCO) in emphysema has not been demonstrated. The purpose of this study was to quantify the degree to which re-breathe DLCO at FRC (DLCO(RB)) differs from single breath DLCO at TLC (DLCO(SB)) in emphysema. In 37 consecutively recruited patients with moderate to severe emphysema (FEV1/FVC 40%±10% predicted), DLCO(RB) as % predicted of 91 controls without cardiopulmonary disease was 79%±24%, significantly greater than % predicted DLCO(SB) (44%±19%; p<0.0001). DLCO(RB)/DLCO(SB) was inversely proportional to FEV1% predicted (R = -0.47, p=0.004), and FEV1/FVC (R = -0.54, p<0.001). These data indicate that a 10s single breath DLCO maneuver progressively under-represents re-breathe lung diffusing capacity in emphysema as airflow obstruction increases.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Emphysema / physiopathology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Pulmonary Diffusing Capacity / methods*
  • Respiration