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Gas trapping in normal infants and in infants with cystic fibrosis
Author(s) -
Castile Robert G.,
Iram Durdana,
McCoy Karen S.
Publication year - 2004
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.10446
Subject(s) - nitrogen washout , functional residual capacity , medicine , lung volumes , plethysmograph , cystic fibrosis , pulmonary function testing , air trapping , lung function , volume (thermodynamics) , lung , anesthesia , physics , quantum mechanics
Two different methods for estimating trapped gas volume have been described in the literature. The purpose of this study was to use both of these methods to estimate and compare trapped gas volumes in normal infants and infants with cystic fibrosis (CF). Thirty normal infants and 29 infants with CF, ages 1 month to 3 years, were studied. Pulmonary function tests, including raised volume forced expiratory flows, plethysmographic functional residual capacity (FRC pleth ), and fractional lung volumes, were measured. Then functional residual capacity was measured by nitrogen washout (FRC nitrogen ). Following nitrogen washout, lungs were then inflated three times to 30 cm H 2 O, using 100% oxygen. This process was repeated until no further nitrogen could be washed from the lungs. The volume of trapped gas (tg) was calculated from the total additional amounts of nitrogen expired following lung inflations. The difference between FRC pleth and FRC nitrogen provided a second estimate of trapped gas volume (delta V). Mean tg and delta V values for normal infants were 2.5 ± 3.5 ml and 15.6 ± 30.4 ml, respectively. Mean tg and delta V values for infants with CF were 5.8 ± 7.7 ml and 33.2 ± 43.8 ml, respectively. Both tg and delta V did not differ significantly between normal infants and infants with CF. Measured following raised volume forced expiratory maneuvers, delta V and tg do not distinguish infants with CF from normal infants as well as do other currently available tests of infant lung function. Pediatr Pulmonol. 2004; 37:461–469. © 2004 Wiely‐Liss, Inc.