112 CONSTRICTION AND RELAXATION OF THE DUCTUS ARTERIOSUS IN SMALL PRETERM INFANTS

Abstract

Small prematures with respiratory distress (RD) are at high risk for patent ductus arteriosus (PDA) and left-right shunt. Nearly all infants 5 severe). PDA was evaluated by echo (LA/Ao, left ventricular dimensions= LVED) and aortography. Based on the caliber of PDA (Ductus/aorta diameter=PDA/Ao) infants were placed in 3 groups. The PDA was constricted in 17 grp I infants who also had less RD (P<.01). Those infants with larger PDA had larger LA/Ao (P<.05). However, 10/17 infants with constricted ductus and mild RD had abnormal LA/Ao (4 with abnormal LV). Only 15/32 ultimately received indomethacin (4 grp I, 4 grp II). Conclusions: (1) Early constriction of PDA is a common occurrence in very small infants with mild-moderate RD. (2)Abnormal echo dimensions in small asphyxiated infants may be related to factors such as left-right ductal shunt, LV dysfunction or artifacts. (3) Ductal relaxation occurs and contributes to the later increase of left-right shunting.