Neonatal respiratory mechanics and development of bronchial hyperresponsiveness in preterm infants.
BACKGROUND
In preterm ventilated infants, irreversible damage to the airway mucosa in the neonatal period might be related to the development of bronchial hyperresponsiveness (BHR) in subsequent years.


OBJECTIVE
To evaluate whether neonatal indicators of long-term respiratory morbidity, respiratory system compliance (Crs) and resistance (Rrs), were causally related to bronchial responsiveness at the age of 2 and whether these relationships were affected by other factors.


METHODS
Mean neonatal Crs and Rrs of the first 3 days of life were assessed using the single breath occlusion technique. Bronchial challenge tests were performed at 2 years of age. When wheezing occurred during chest auscultation or oxygen saturation decreased below 90%, the provocative concentration of methacholine was recorded.


METHODS
Forty-five preterm infants of <37 weeks gestation, being mechanically ventilated within 24 h after birth.


RESULTS
Decreased neonatal Crs was related to BHR (beta per ml/kPa, 0.061; 95% confidence interval, 0.019 to 0.103; p=0.006). Correction was required for radiological gradation of respiratory distress syndrome, the maximal peak inspiratory pressure required during mechanical ventilation and postnatal corticosteroid therapy. Neonatal Rrs, gestational age and birth weight were not related to subsequent BHR development.


CONCLUSIONS
In ventilated preterm infants, decreased neonatal Crs was related to the development of BHR at the age of 2.
Snepvangers
Yvonne
Y
Department of Paediatric Pulmonology, University Medical Centre Utrecht, Utrecht, The Netherlands. yvonne.snepvangers@wanadoo.nl
Peter de Winter
J Peter
JP
Burger
Huibert
H
Brouwers
Hens
H
Van der Ent
Cornelis K
CK
D000328:Adult; D000403:Airway Resistance / Q000502:physiology*; D001249:Asthma / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000209:etiology / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D008170:Lung Compliance / Q000502:physiology*; D008297:Male; D047928:Premature Birth; D015656:Respiratory Mechanics