Diaphragm Function in Very Preterm Infants at 36 Weeks' Postmenstrual Age.

Area of Science:

• Neonatal physiology
• Respiratory medicine
• Pediatric pulmonology

Background:

• Bronchopulmonary dysplasia (BPD) is a chronic lung disease affecting very preterm infants.
• Diaphragmatic function is crucial for respiratory support in neonates.
• Understanding factors influencing diaphragmatic effectiveness is vital for infant respiratory health.

Purpose of the Study:

• To investigate the influence of BPD and antenatal/postnatal factors on diaphragmatic functional effectiveness in very preterm infants.
• To assess diaphragmatic pressure, work of breathing, and ventilation during spontaneous breathing.
• To identify predictors of diaphragmatic functional outcomes.

Main Methods:

• Prospective observational study of 182 very preterm infants at 36 weeks' postmenstrual age.
• Measurement of transdiaphragmatic pressure (Pdi) normalized to tidal volume (Pdi/V_T) and diaphragmatic work of breathing (PTIdi·min^-1).
• Multivariable linear regression used to identify predictive factors for diaphragmatic outcomes.

Main Results:

• Infants with BPD showed lower Pdi/V_T and PTIdi·min^-1 but higher minute ventilation compared to those without BPD.
• Lower birthweight Z-score and presence of BPD were negative predictors for Pdi/V_T.
• Higher gestational age and better early postnatal energy intake positively predicted PTIdi·min^-1.

Conclusions:

• Diaphragmatic functional effectiveness appears unexpectedly improved in infants with BPD.
• This may represent an adaptive response or increased accessory muscle recruitment.
• Antenatal and postnatal factors explained only a minor part of the variance in diaphragmatic effectiveness.