Measurement of single breath-hold carbon monoxide diffusing capacity in healthy infants and toddlers.
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.
Castillo
Andres
A
Department of Pediatrics, Indiana University Medical Center, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana 46202-5225, USA.
Llapur
Conrado J
CJ
Martinez
Tanya
T
Kisling
Jeff
J
Williams-Nkomo
Tamica
T
Coates
Cathy
C
Tepper
Robert S
RS
D001827:Body Height / Q000502:physiology; D001837:Body Weights and Measures; D002248:Carbon Monoxide / Q000032:analysis* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007223:Infant; D008168:Lung / Q000502:physiology; D008176:Lung Volume Measurements / Q000295:instrumentation / Q000379:methods*; D008297:Male; D011650:Pulmonary Alveoli / Q000378:metabolism; D011653:Pulmonary Diffusing Capacity / Q000295:instrumentation / Q000379:methods* / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D014109:Total Lung Capacity / Q000502:physiology
D002248:Carbon Monoxide