69 BLOOD PRESSURE IN PRETERM NEONATES WITH A BIRTH WEIGHT OF 500 TO 1, 250 GRAMS DURING THE FIRST WEEK OF LIFE: NORMATIVE VALUES, USE OF PRESSORS, AND STEROIDS. Issue 1 (1st January 2007) - Adie, M. A.
Abstract : Background: Normal values of blood pressure are well established for healthy term newborn infants. In these infants, blood pressure increases rapidly during the first week and then gradually until 6 weeks of life. In contrast, most very low birth weight infants are not "healthy" and the normative value of blood pressure in these infants remains controversial. Methods: Four hundred fifteen preterm infants with birth weights of 500 to 1, 250 g were born at LAC+USC Medical Center between 1995 and 2005. Of these, 36 infants were excluded due to severe malformation or death during first week and the remaining 379 infants were entered in the study. Mean arterial pressure (MAP) was measured through an indwelling umbilical arterial catheter or peripheral arterial line. MAP values from each day were entered prospectively into the database. Lower limit of acceptable MAP was arbitrarily set at a value of gestational age (GA) plus 3 mm Hg at birth and appropriately adjusted for postnatal age. MAP lower than this limit triggered use of pressors and, if nonresponsive, addition of steroids. Results: Conclusions: Initial MAP among the extremely low birth weights is similar to those observed in infants > 1, 000 g. MAP increased with increasing birth weight and advancing postnatal age in all weight groups. MAP observed in infants receiving pressors was similar to that seen in stable infants, who did not receive pressors. Our goal of maintaining MAP equal to GA +3 appears to be a reasonable target. Short- and long-term outcomes of these infants are in progress. Our data from a large number of preterm infants provide a basis for acceptable MAP values during the first week of life.