Pulmonary diffusing capacity in healthy African-American and Caucasian children.

Previous studies of pulmonary diffusing capacity in healthy children primarily focused upon Caucasian (C) subjects. Since lung volumes in African-Americans (AA) are smaller than lung volumes in C subjects of the same height, diffusing capacity values in AA children might be interpreted as low or abnormal using currently available equations without adjusting for race. Healthy AA (N = 151) and C (N = 301) children between 5 and 18 years of age performed acceptable measurements of single breath pulmonary diffusing capacity for carbon monoxide (DLCO ) and alveolar volume (VA ) according to current ATS/ERS guidelines. The natural log of DLCO and VA were associated with height, gender, age, and race; AA children had lower DLCO and VA compared to C children. Adjustment of DLCO for Hemoglobin (Hgb) resulted in no significant difference in DLCO among these healthy subjects with normal Hgb. In summary, we report prediction equations for DLCO and VA that include adjustment for race (C; AA) demonstrating that AA have lower DLCO and VA compared to C children for the same height, gender, and age.

Pulmonary diffusing capacity in healthy Caucasian children.

Previous studies of pulmonary diffusing capacity in children differed greatly in methodologies; numbers of subjects evaluated, and were performed prior to the latest ATS/ERS guidelines. The purpose of our study was to establish reference ranges for the diffusing capacity to carbon monoxide (DL(CO) ) and alveolar volume (V(A) ) in healthy Caucasian children using current international guidelines and contemporary equipment. Healthy children from the United States (N = 303) and from Australia (N = 176) performed acceptable measurements of single breath pulmonary diffusing capacity and alveolar volume according to current ATS/ERS guidelines. The natural log of DL(CO) and V(A) were associated with height, age and an age-sex interaction term, while DL(CO) /V(A) was related to height and the age-sex interaction term only. Adjustment of DL(CO) for hemoglobin (n = 303; USA data only) resulted is a small but significant decrease in DL(CO) of ∼1% but did not significantly alter the regression equations. In this dataset there was no influence of center for DL(CO) or DL(CO) /V(A) , while Australian children had a statistically smaller V(A) (mean difference 0.14 L after accounting for height, age and age-sex; P = 0.012). We report that diffusing capacity outcomes can be collated from multiple centers using similar equipment and collection protocols. Using collated data we have derived regression equations for pulmonary diffusing capacity outcomes in healthy Caucasian children aged 5-19 years.

Spirometry in 3- to 6-year-old children with cystic fibrosis.

Spirometry is routinely used to assess pulmonary function of older children and adults with cystic fibrosis (CF); however, few data exist concerning the preschool age group. We have reported normative spirometric data for 3- to 6-year-old children. The current study was designed to assess a similarly aged group of clinically stable patients with CF. Thirty-three of 38 children with CF were able to perform 2 or 3 technically acceptable maneuvers. These patients had significantly decreased FVC, FEV(1), FEV(1)/FVC, and FEF(25-75) when expressed as z scores (number of SD from predicted): -0.75 +/- 1.63, -1.23 +/- 1.97, -0.87 +/- 1.33, and -0.74 +/- 1.63, respectively. There were significant positive correlations of the Brasfield radiological score with FVC and FEV(1) z scores (r(2) = 0.26, p < 0.01 and r(2) = 0.24, p < 0.01). In addition, homozygous patients for the DeltaF508 mutation had lower z scores for FVC (-1.21 versus 0.47, p < 0.01) and FEV(1) (-1.38 versus 0.21, p < 0.05) than heterozygous patients. Of the 14 patients who had full flow-volume spirometric measurements during infancy, 10 had FEF(25-75) z scores greater than -2 at both evaluations. Our findings suggest that spirometry can successfully be used to assess lung function in preschool children with CF and has the potential for longitudinal assessment from infancy through adulthood.