Cardiorespiratory status in long-term survivors of prematurity, with and without hyaline membrane disease.
Forty-eight children, born at less than 33 weeks' gestation and without bronchopulmonary dysplasia (BPD) or Wilson-Mikity syndrome (WM) were studied at a mean age of 9.1 years, to identify the incidence and possible factors contributing to the development of long-term abnormalities in pulmonary function. As neonates, 30 children had hyaline membrane disease (HMD) of whom 21 required ventilation. Eighteen did not have HMD, of whom 9 required ventilation for nonrespiratory reasons. All patients had grown normally. Four of the 48 (8.3%) had clinical asthma, 5 had persisting chest x-ray abnormalities (10.6% of 47 chest x-rays performed), each having been ventilated for HMD. There was a close association between duration of ventilation, oxygen administration, and subsequent abnormal chest x-ray. Electrocardiogram and M-mode echocardiograms were normal in all but 2 patients. Only 3 patients had significant restrictive lung disease, 3 had evidence of significant airways obstruction, and 13 (27.7%) had signs of air trapping. Methacholine challenge was positive in 30 of 46 patients (65.2%). The incidence of a positive methacholine challenge did not correlate with history of HMD, duration of ventilation, or high oxygen administration. There is an increased incidence of airway hyperreactivity in survivors of prematurity, not associated with any identified therapeutic maneuver during the neonatal period.