Ventilator-induced diaphragmatic dysfunction in extremely preterm infants: A pilot ultrasound study

Purpose: To investigate the development of diaphragmatic dysfunction in ventilated extremely preterm infants (EPI) using diaphragm ultrasound (DU). Methods: : EPI of less than 28 weeks’ gestational age who required mechanical ventilation within six hours of birth were included in this prospective, observational study. The DU was performed once a day until four days of life. End-inspiratory and end-expiratory thicknesses of the diaphragm were measured and the diaphragm thickening fraction was calculated. Results: : A total of 20 EPI were enrolled. After intubation, there was a progressive reduction in end-inspiratory thicknesses of the diaphragm from baseline to day 1 ( P < 0.001), but not from day 1 to day 2 ( P = 0.078), day 2 to day 3 ( P = 1.0), or day 3 to day 4 ( P = 1.0). There was also a significant reduction in the diaphragm thickening fraction from baseline to day 1 ( P < 0.001), but not from day 1 to day 2 ( P = 1.0), day 2 to day 3 ( P = 1.0), or day 3 to day 4 ( P = 1.0). Conclusions: : This study provides the first evidence of diaphragmatic dysfunction in ventilated EPI. We demonstrated a rapid progression of ventilator-induced diaphragmatic dysfunction, with a significant reduction in diaphragm thickness and thickening fraction within 24 hours of ventilation.