CHEST-WALL MOTION IN PRETERM INFANTS USING RESPIRATORY INDUCTIVE PLETHYSMOGRAPHY

Preterm infant tidal breathing may be different from that of healthy f ull-term infants because of various features of the premature thorax. The purpose of this project was to describe chest wall motion in the p reterm infant (gestational age <37 weeks) and compare it with chest wa ll motion data in a group of healthy, full-term infants. We wanted to use an objective bedside method for assessment with minimal disruption to the infant. The study population consisted of 61 preterm human inf ants whose mean(+/-SD) postconceptional age at time of study was 35.3/-2.1 weeks. During the study, the infants were quietly awake in a pro ne position. Preterm infants had initially been admitted to a level II I neonatal intensive care unit for acute management and had been trans ferred to a step-down area, where they were in stable condition for st udy. Data were collected with a semiquantitatively calibrated, noninva sive respiratory inductive plethysmograph. Mean(+/-SD) phase angle was significantly greater in preterm infants than in fullterm infants (60 .6+/-39.8 degrees versus 12.5+/-5.0 degrees, respectively, p less than or equal to 0.0001). The laboured breathing index was significantly g reater in preterm infants than in full-term infants (1.35+/-0.35 versu s 1.01+/-0.01, respectively, p=0.001). The ribcage contribution to bre athing did not differ significantly between preterm and full-term infa nts (25.5+/-17.7% versus 36.3+/-14.4%, respectively, p=0.11). These re sults indicate a significant increase in the degree of ribcage and abd omen asynchrony in the preterm subjects compared to the full-term infa nts. Plethysmography provided a time-efficient and objective method of assessing chest wall motion in this fragile population.