Development of lung diffusion to adulthood following extremely preterm birth

Area of Science:

• Pulmonary physiology
• Neonatology
• Pediatric pulmonology

Background:

• Gas exchange in extremely preterm (EP) infants relies on fetal lungs.
• Childhood lung diffusing capacity for carbon monoxide (D_LCO) is reduced in EP infants, but its longitudinal development is unknown.

Purpose of the Study:

• To describe the longitudinal development of D_LCO and its subcomponents from childhood to adulthood in EP subjects compared to term-born controls.

Main Methods:

• Two cohorts of EP infants (gestational age ≤28 weeks or birthweight ≤1000g) were studied at two time points.
• Single-breath D_LCO was measured, with subcomponents (membrane diffusion [D_M] and pulmonary capillary blood volume [V_C]) calculated.
• EP subjects were compared with matched term-born controls.

Main Results:

• Age-, sex-, and height-standardized D_LCO and transfer coefficients (K_CO) were reduced in EP subjects compared to controls, persisting into early adulthood.
• Alveolar volume (V_A) was similar between groups.
• Development occurred in parallel, with no catch-up growth or decline observed by age 25 years; membrane diffusion appeared most affected.

Conclusions:

• Pulmonary diffusing capacity is reduced in EP individuals and develops in parallel to term-born subjects.
• No catch-up growth or decline in D_LCO was observed from childhood to adulthood.
• These findings highlight the long-term impact of extreme prematurity on lung function.