与足月产儿比较，早产儿肺功能可能持续性减弱

hy2007

研究者认为应继续研究，找到早产儿出现肺功能持续性减弱的原因，他们认为可能的原因是：气道顺应性的增大；支气管硬度的增加；肺弹性回缩力的减弱
Preterm Infants May Have Persistently Decreased Lung Function vs Full-Term Infants

December 15, 2007 — Preterm infants have persistently decreased lung function compared with full-term infants, according to the results of a study reported in the December 15 issue of the American Journal of Respiratory and Critical Care Medicine.

\"We have shown that healthy preterm infants have reduced lung function in the first months of life that persists into the second year of life,\" senior author Marcus Herbert Jones, MD, PhD, from Pontificia Universidade Catolica do Rio Grande do Sul in Brazil, says in a news release. \"Healthy infants born prematurely may have smaller-sized airways relative to the lung volume.\"

An earlier study by Dr. Jones' group showed that healthy preterm infants born at 32 to 34 weeks' gestation without respiratory complications had decreased forced expiratory flows and normal forced vital capacities at 2 months of age. This study determined whether these infants had evidence of improvement or ''catch-up'' in lung function by 2 years of age.

The authors compared longitudinal measurements of forced expiratory flows by the raised volume rapid thoracic compression technique in the first and the second years of life for 26 healthy infants born prematurely vs 24 infants born at full term. Mean weeks' gestation in the preterm group was 32.7 weeks (range, 30 – 34 weeks). Average age at the first measurement was about 10 weeks and was 15 months at the second measurement.

The preterm group continued to have decreased forced expiratory flows and normal forced vital capacities in the first and second years of life compared with the full-term group, even though their increases in lung function with growth were similar to those of full-term infants.

\"We were unable to detect a catch-up period during the study,\" Dr. Jones said. \"There was no change in the rate of increase of lung function when compared to full-term infants.\"

At both time points, maternal tobacco smoking was also associated with reduced lung function in both premature and full-term infants.

Surprisingly, premature infants with more fully developed lungs and less need for oxygen supplementation after birth had greater respiratory problems than did premature infants who required prolonged use of oxygen supplementation.

\"It is a counterintuitive finding,\" Dr. Jones concluded. \"My interpretation is that in preterm infants, supplemental oxygen may be a marker of a less mature lung, which may have a better long-term respiratory prognosis than infants with accelerated maturation due to prenatal events such as infection and inflammation.\"

The investigators recommend additional research to determine why preterm infants have persistent deficits in lung function, suggesting possible explanations such as more compliant airways, increased bronchial tone, or decreased pulmonary elastic recoil.

A potential study limitation is recruitment and testing of subjects at different centers.

\"Our findings suggest that the increase in lung function during the first year of life was proportional to somatic growth and similar for premature and full-term infants,\" the study authors conclude. \"The persistence of reduced expiratory flows in healthy preterm infants may contribute to their increased risk of recurrent respiratory illnesses early in life. Future studies are required to determine the mechanisms for the persistently reduced flows in healthy infants born prematurely, as well as to evaluate the effects of even greater prematurity on lung growth,\" they write.

The authors have disclosed no relevant financial relationships.