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Moment analysis of multibreath nitrogen washout in healthy preterm infants
Author(s) -
Shao Hongqian,
Sandberg Kenneth,
Sjöqvist BengtArne,
Hjalmarson Ola
Publication year - 1998
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/(sici)1099-0496(199801)25:1<52::aid-ppul6>3.0.co;2-q
Subject(s) - medicine , functional residual capacity , nitrogen washout , gestational age , washout , birth weight , lung volumes , nuclear medicine , pregnancy , lung , biology , genetics
Moment analysis (MA) of multibreath nitrogen washout (MBNW) has not previously been applied to newborn infants. The aim of the present study was to adapt this method to healthy preterm infants using an improved technique suitable for small infants, and to determine reference values of MA. Twenty healthy preterm infants with a mean birth weight (± SD) of 1,666 ± 402 g and a mean gestational age of 31.3 ± 2.1 weeks were studied during their first 7–28 days of life. Computerized bedside equipment with very low dead space was constructed. The limits of normal variability were determined from results of duplicate studies. Outcome variables included functional residual capacity (FRC), the first‐to‐zeroth moment ratio (M 1 /M 0 ), the second‐to‐zeroth moment ratio (M 2 /M 0 ), and the lung clearance index (LCI). The starting point for MA had considerable impact on the results. Mean M 1 /M 0 and M 2 /M 0 were 2.18 ± 0.18 and 8.71 ± 1.24, respectively. No significant relation between moment ratios and weight, gender or age was found. Intrasubject coefficients of variation (CV) for M 1 /M 0 (7.9 ± 5.9%) and for M 2 /M 0 (12.1 ± 9.1%) and intersubject CV for M 1 /M 0 (8%) and M 2 /M 0 (14%) were similar to those reported in children and adults. Mean lung clearance index was 10.8 ± 1.4 and intra‐ and intersubject CVs were 11.3 ± 8.9% and 13%, respectively. Mean functional residual capacity (FRC) was 22.5 ± 2.1 ml/kg. Mean intra‐ and intersubject CVs for FRC were 8.3% and 9%, respectively. We conclude that the MBNW test can be performed by a simple bedside method and that MA appears to be a suitable method for measuring gas mixing in preterm infants. Pediatr. Pulmonol. 1998; 25:52–58. © 1998 Wiley‐Liss, Inc.