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Respiratory muscle strength in healthy infants and those with surgically correctable anomalies

Research output: Contribution to journalArticlepeer-review

Original languageEnglish
Pages (from-to)71-78
Number of pages8
JournalPediatric Pulmonology
Early online date2014
E-pub ahead of print2014

King's Authors


Assessment of respiratory muscle strength provides important diagnostic and prognostic information. Normative data in healthy, term infants is, however, limited. Surgically correctable birth defects, congenital diaphragmatic hernia (CDH) and abdominal wall defects (AWD), commonly have impaired diaphragm function. The study aims were to obtain normative data for respiratory muscle strength in healthy, term born infants at birth and at 6 weeks postnatal age (PNA) and to investigate the influence of growth and maturation on inspiratory muscle strength in CDH/AWD infants. Maximal inspiratory (cPimax) and expiratory (cPemax) pressures during crying were measured at birth in 67 healthy, term born infants (mean (SD) gestational age (GA) 39.4 (1.7) weeks) and reassessed in 27 at 6 weeks PNA. cPimax and functional residual capacity (FRC) (22.3 (4.2) ml/kg) were also measured in 23 infants with AWD/CDH (mean (SD) GA 36.9 (2.1) weeks) and reassessed in 16 at median (range) 6.5 (1.5–15) months PNA. In healthy infants, mean (SD) cPimax was 88.8 (19.33) cmH2O and cPemax 61.8 (13.5) cmH2O at birth, increasing significantly at followup to 100.9 (15.2) cmH2O (P < 0.05) and 82.6 (19.4) cmH2O (P < 0.001) respectively. Mean (SD) cPimax was significantly lower (47.5 (22.4) cmH2O, P < 0.0001) in AWD/CDH infants compared to healthy infants at birth but had increased significantly to 88.1 (27.6) cmH2O (P < 0.0001) at followup which correlated significantly with increases in FRC (r2 = 0.33, P = 0.0263). Infants with AWD and CDH have significantly reduced inspiratory muscle strength compared to healthy term born infants but strength increases markedly in early life.

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