Measurement of single breath-hold carbon monoxide diffusing capacity in healthy infants and toddlers

Pediatr Pulmonol. 2006 Jun;41(6):544-50. doi: 10.1002/ppul.20403.


We describe a method for measuring carbon monoxide diffusing capacity (DL(CO)) and alveolar volume (V(A)) in sleeping infants, using a single 4-sec breath-hold technique. The breath-hold maneuver is obtained by inducing a respiratory pause of the respiratory system. Several inflations of the respiratory system with room air to a lung volume with an airway pressure of 30 cmH2O (V30) inhibit inspiratory effort. The respiratory system is then inflated with a test gas containing helium and a stable isotope of carbon monoxide (C18O), and a respiratory pause is maintained for 4 sec and followed by passive expiration to functional residual capacity. Concentrations of helium and C18O are continuously measured with a mass spectrometer. Twelve healthy infants between 6-22 months of age were evaluated. For 9 of 12 subjects, duplicate measurements of alveolar volume at 30 cmH2O (V(A30)) and DL(CO) were within 10%, which are the recommendations for older children and adults. Among these 9 subjects, values of V(A30) and DL(CO) increased with increasing body length (r2 = 0.82 and 0.79, respectively). The remaining 3 subjects had two values within 10-15%. Measurement of V(A) and DL(CO) with the single breath-hold technique at an elevated lung volume offers the potential to assess growth and development of the lung parenchyma early in life.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Body Height / physiology
  • Body Weights and Measures
  • Carbon Monoxide / analysis*
  • Carbon Monoxide / pharmacokinetics
  • Female
  • Humans
  • Infant
  • Lung / physiology
  • Lung Volume Measurements / instrumentation
  • Lung Volume Measurements / methods*
  • Male
  • Pulmonary Alveoli / metabolism
  • Pulmonary Diffusing Capacity / instrumentation
  • Pulmonary Diffusing Capacity / methods*
  • Pulmonary Diffusing Capacity / physiology
  • Pulmonary Gas Exchange / physiology
  • Total Lung Capacity / physiology


  • Carbon Monoxide