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Respiratory muscle strength in healthy infants and those with surgically correctable anomalies
Zainab Kassim1, John Moxham, Mark Davenport
1King's College London, Division of Asthma Allergy and Lung Biology, Department of Child Health and Kings College Hospital NHS Foundation, London, UK.
Insights
Respiratory muscle strength in term infants is crucial for diagnosis. This study provides normative data and shows that infants with congenital diaphragmatic hernia (CDH) and abdominal wall defects (AWD) have weaker inspiratory muscles at birth but improve significantly with age.
Area of Science:
- Pediatric Pulmonology
- Neonatal Physiology
- Respiratory Mechanics
Background:
- Respiratory muscle strength assessment is vital for diagnosing and predicting outcomes in infants.
- Limited normative data exists for healthy term infants, hindering accurate clinical interpretation.
- Congenital diaphragmatic hernia (CDH) and abdominal wall defects (AWD) are associated with impaired diaphragm function.
Purpose of the Study:
- To establish normative data for respiratory muscle strength in healthy term infants at birth and 6 weeks postnatal age.
- To evaluate the impact of growth and maturation on inspiratory muscle strength in infants with CDH/AWD.
- To compare respiratory muscle strength between healthy infants and those with CDH/AWD.
Main Methods:
- Maximal inspiratory (cPimax) and expiratory (cPemax) pressures were measured during crying in healthy term infants at birth and 6 weeks postnatal age.
- cPimax and functional residual capacity (FRC) were measured in infants with AWD/CDH at birth and reassessed at follow-up.
- Statistical analysis was performed to compare groups and assess correlations.
Main Results:
- Healthy infants showed significant increases in cPimax and cPemax from birth to 6 weeks postnatal age.
- Infants with AWD/CDH exhibited significantly lower cPimax at birth compared to healthy infants.
- AWD/CDH infants demonstrated significant improvement in cPimax by follow-up, correlating with increased FRC.
Conclusions:
- Infants with AWD and CDH have substantially reduced inspiratory muscle strength compared to healthy term-born infants.
- Respiratory muscle strength in infants with AWD/CDH shows marked improvement during early life.
- Normative data and longitudinal assessments are essential for understanding respiratory muscle development in vulnerable infant populations.
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.
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