title: Respiratory muscle strength in healthy infants and those with surgically correctable anomalies.
abstract: 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) cmH2 O and cPemax 61.8 (13.5) cmH2 O at birth, increasing significantly at followup to 100.9 (15.2) cmH2 O (P < 0.05) and 82.6 (19.4) cmH2 O (P < 0.001) respectively. Mean (SD) cPimax was significantly lower (47.5 (22.4) cmH2 O, P < 0.0001) in AWD/CDH infants compared to healthy infants at birth but had increased significantly to 88.1 (27.6) cmH2 O (P < 0.0001) at followup which correlated significantly with increases in FRC (r(2)  = 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.
authors.affiliation: King's College London, Division of Asthma Allergy and Lung Biology, Department of Child Health and Kings College Hospital NHS Foundation, London, UK.
authors.forename: Zainab
authors.initials: Z
authors.lastname: Kassim
authors.forename: John
authors.initials: J
authors.lastname: Moxham
authors.forename: Mark
authors.initials: M
authors.lastname: Davenport
authors.forename: Kypros
authors.initials: K
authors.lastname: Nicolaides
authors.forename: Anne
authors.initials: A
authors.lastname: Greenough
authors.forename: Gerrard F
authors.initials: GF
authors.lastname: Rafferty
mesh_terms: D034861:Abdominal Wall / Q000002:abnormalities / Q000601:surgery*; D001724:Birth Weight / Q000502:physiology; D003448:Crying / Q000502:physiology; D045853:Exhalation / Q000502:physiology; D005500:Follow-Up Studies; D065630:Hernias, Diaphragmatic, Congenital / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D001239:Inhalation / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology*; D012129:Respiratory Function Tests; D012132:Respiratory Muscles / Q000502:physiology*
keywords: human; infant; maximal inspiratory muscle strength; respiratory muscle strength; surgically correctable anomalies