UMBILICAL ARTERY CATHETERS AND BLOOD-FLOW VELOCITIES IN THE SUPERIOR MESENTERIC-ARTERY - EFFECT OF INSERTION, REMOVAL, ASPIRATION, AND BOLUS INFUSION

Purpose. We studied whether umbilical artery catheters (UACs) affect b lood flow in the superior mesenteric artery (SMA) of neonates. Methods . Noninvasive duplex pulsed Doppler sonography was used to measure pea k systolic velocity, end-diastolic velocity, and mean flow velocity in the SMA. The resistance index and pulsatility index were calculated f rom these data. Thirty-two infants weighing 450-2,520 g at birth were enrolled in the study. Gestational age at birth was 24-37 weeks. Eight een infants were studied before and after UAC insertion. Twenty infant s were studied before and after UAC removal. Eleven infants with UACs were studied before and during aspiration of blood from the UAC and du ring bolus infusion of 5% dextrose solution into the UAC. Data were co mpared before and after UAC insertion; before and after UAC removal; a nd before and during aspiration and during bolus infusion. Results. Bl ood flow velocities and vascular resistance were similar in all compar isons except for increases in end-diastolic and mean velocities after UAC insertion. Conclusions. Insertion and removal of UACs, aspiration of blood from UACs, and bolus infusion of fluids into UACs do not dimi nish blood flow velocity or increase vascular resistance in the SMA. ( C) 1998 John Wiley & Sons, Inc.