PULMONARY-FUNCTION DURING THE FIRST YEAR OF LIFE IN HEALTHY INFANTS BORN PREMATURELY

Premature birth is associated with increased respiratory morbidity, We investigated cross-sectionally, in 69 healthy infants who had never h ad cardiorespiratory problems, whether premature birth is associated w ith diminished pulmonary function. The study comprised 26 healthy infa nts born prematurely (PT), median gestational age 32 (26-36) weeks, an d 43 healthy controls born full-term (FT), median gestational age 40 ( 37-42) weeks, Static respiratory system compliance (Crs) was assessed by weighted spirometry, combined with the measurement of the functiona l residual capacity by closed circuit helium dilution (FRCHe) and with assessment of ventilation distribution from the mixing index (MI). Re peatability of these indices was also assessed. Premature and full-ter m infants had the same length-corrected FRCHe; their Crs was different , but the difference disappeared when gestational age was taken into a ccount, Mixing index was unrelated to body size and was not different between full-term and premature infants, Crown-heel length and lung vo lume were not different for any postconceptional age. However, infants born prematurely were smaller and had smaller lung volume at any post natal age compared to those born at term, Repeatability of the indices was fair. These findings suggest that gestational age <37 weeks is as sociated with normal respiratory system mechanics for body size, and n ormal distribution of ventilation in healthy infants who never had car diorespiratory problems.