DECLINE IN RESPIRATORY COMPLIANCE DURING THE FIRST WEEK OF LIFE IN INFANTS ≤ 1000 g

Single measurements of respiratory compliance (Crs) in premature infants have been reported; however serial recordings have not been published. Monitoring respiratory mechanics could improve ventilation techniques. Using a non-invasive single breath occlusion technique (LeSouef et al: Am Rev Resp Dis 129:521, 1984) Crs was measured serially in 10 ventilated infants ≤ 1000 g. 2 infants with very low Crs ≤ .25 ml·cm H2O−1 died on day 1 from respiratory failure. In a further 2 infants with severe lung disease (Mean airway pressure [MAP] 12-15 cm H2O on day 2) no change in Crs occurred throughout the first week (.4-.5 ml· cmH2O−1). Six infants showed a striking decline in Crs (Table).This fall in Crs was also seen in those infants ventilated mainly for apneas: MAP in cases 1-3 ranged from 3.5-7.2 cm H2O during the first week, and FiO2 from .21-.34. We conclude that even modest mechanical ventilation in infants ≤ 1000 g may be associated with an early, rapid and progressive decline in. Crs.