title: Spirometry and chest wall dimensions in achondroplasia.
abstract: Standard values for pulmonary function in short-limbed dwarfism are not available. Therefore, chest diameters and expiratory spirograms were measured in 58 female and 44 male subjects between 7 and 60 years of age with achondroplasia, the most common form of dwarfism. Standing height in adults was 49.6 +/- 3.2 (SD) inches with a sitting/standing height ratio of 0.66 (normal 0.52-0.53). Despite extremely short stature, only AP chest diameters in males were smaller than control subjects of similar age. The following equations were derived for forced vital capacity (FVC): males (under 25 years), FVC(L) = -3.56 + 0.162 X sitting height (in) + 0.067 X age (yrs); males (over 25 years), FVC(L) = -0.73 + 0.162 X sitting height (in) -0.047 X age (yrs); females (under 20 years), FVC(L) = -3.56 + 0.150 X sitting height (in) + 0.067 X age (yrs); females (over 20 years), FVC(L) = -1.92 + 0.150 X sitting height (in) -0.016 X age (years). Similar prediction equations were derived for FEV1 and FEF25-75%: FEV1/FVC % was 84.2 (+/- 6.5) for females and 88.0 (+/- 6.5) for males. We also compared the observed FVC measurements to values calculated using standing heights derived from the subject's sitting height, assuming a normal body proportion. The observed vital capacity in achondroplasia was only 67.6 (+/- 19.2) percent of that predicted for normally proportioned females and 72.4 (+/- 13.6) percent for males, suggesting reduced vital capacity in achondroplasia, due to reduced chest wall compliance or abnormal lung growth.
authors.affiliation: Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD.
authors.forename: D C
authors.initials: DC
authors.lastname: Stokes
authors.forename: R E
authors.initials: RE
authors.lastname: Pyeritz
authors.forename: R A
authors.initials: RA
authors.lastname: Wise
authors.forename: D
authors.initials: D
authors.lastname: Fairclough
authors.forename: E A
authors.initials: EA
authors.lastname: Murphy
mesh_terms: D000130:Achondroplasia / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D002648:Child; D005260:Female; D005540:Forced Expiratory Flow Rates; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D013147:Spirometry; D013909:Thorax / Q000473:pathology*; D014797:Vital Capacity