title: Comparison of carbon monoxide (CO) single breath pulmonary diffusing capacity with non-rebreathing, open-circuit CO pulmonary diffusing capacity in healthy children.
abstract: BACKGROUND
  The standard technique for assessing pulmonary diffusing capacity of the lungs (DL) for carbon monoxide (CO) is the single breath (SB) technique. SB_DLco in children can be problematic because it requires a vital capacity >1.5 L. We have developed an open-circuit technique (OC), which uses the wash-in of CO over a series of 8-10 normal breaths that does not require rebreathing. In this study, we compared the SB_DLco against the OC_DLco.
  
  
  METHODS
  Nineteen healthy children between 7 and 18 years performed SB_DLco and OC_DLco tests. The mean SB_DLco was significantly larger than the mean OC_DLco. The mean difference OC_DLco minus SB_ DLco was: -2.92 +/- 4.21 ml/min/mm Hg, though the difference was negatively correlated with the mean of the two (r = 0.73). The lower mean OC_DLco was in part due to lower lung volume (as measured by alveolar volume (VA)) during the maneuver. In both groups there was a positive correlation between VA and DLco, and the mean VA was -2.17 +/- 1.07 L lower using OC compared to SB. The difference was again negatively correlated with the mean (r = 0.82). The mean OC minus SB difference in DLco/VA was: 6.06 +/- 1.98 ml/min/mm Hg/L, though this difference was positively correlated with the mean, r = 0.76.
  
  
  CONCLUSIONS
  We found a good correlation between both techniques for DLco, VA, and DLco/VA. The OC offers the advantage of minimal subject cooperation, and may be preferable to use in children.
authors.affiliation: Medical Staff Administration, Shriners Hospitals for Children, Galveston, Texas 77550, USA. oesuman@utmb.edu
authors.forename: Oscar E
authors.initials: OE
authors.lastname: Suman
authors.forename: Suchmor
authors.initials: S
authors.lastname: Thomas
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Beck
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Mlcak
authors.forename: David N
authors.initials: DN
authors.lastname: Herndon
mesh_terms: D000293:Adolescent; D002248:Carbon Monoxide / Q000378:metabolism*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D011650:Pulmonary Alveoli / Q000502:physiology; D011653:Pulmonary Diffusing Capacity / Q000502:physiology*; D012129:Respiratory Function Tests / Q000379:methods*
chemical_list: D002248:Carbon Monoxide