Differences in serum glucose determinations in infants with umbilical artery catheters

Differences in serum glucose values obtained from different extremities in newborns with umbilical artery catheters (UAC) through which a dextrose solution was administered were studied. Control infants (n = 20) had no difference in simultaneous capillary glucose values obtained from both lower extremities. Infants with a low UAC had a significant difference between two (both lower extremities) or three (both lower and one upper extremity) simultaneous capillary glucose values. Infants with a high UAC did not. In the low UAC group, the serum glucose value was highest in the lower extremity through which the UAC entered the aorta and lowest in the upper extremity. The elevation in glucose value was related to the glucose infusion rate corrected for infant size (mg/kg/min). Clinicians caring for infants with low UACs should be aware of this potential error in order to prevent erroneous decision-making.