Respiratory mechanics in very low birth weight infants during continuous versus intermittent gavage feeds

This study was designed to determine whether respiratory mechanics in stable, very low birth weight infants changed after replacing intermittent feeds with continuous feeding. We measured static respiratory system compliance, respiratory system resistance, functional residual capacity (FRC), and tidal volume immediately before feeds and at 20, 60, and 120 min after feeds, and again the next day on continuous feeds. Patients selected for enrollment into the study needed to fulfill the following criteria: 1) birth weight and postnatal weight < 1,500 g, 2) no need for mechanical ventilation, positive airway pressure, or supplemental oxygen, 3) receiving and tolerating at least 100 mL/kg/day of intermittent gavage feeds, and 4) no change in methylxanthine or diuretic dosage for 3 days before the study. Respiratory mechanics were measured using the SensorMedics 2600 Pediatric Pulmonary Cart (Yorba Linda, CA). We studied 16 infants (gestational age 28.3 +/- 3.7 weeks, mean +/- SD) at a postnatal age of 10-82 days. The average interindividual coefficient of variance was 20 +/- 2% for static compliance, 35 +/- 6% for resistance, 18 +/- 3% for FRC, and 19 +/- 3% for tidal volume. Repeated-measures analysis of variance did not reveal any significant difference in respiratory mechanics with intermittent vs. continuous feeding. The data suggest that static respiratory mechanics in stable, very low birth weight infants are not affected by changing enteral feeds from intermittent gavage to a continuous schedule.