Fenoldopam to Prevent Renal Dysfunction in Indomethacin Treated Preterm Infants (Fenaki)

The investigators will conduct a prospective, blinded, randomized, placebo-controlled trial with a sample size of 20 patients in each of the two arms (fenoldopam vs placebo) based upon a difference in serum creatinine by one standard deviation. Fluid and salt intake will be held constant within clinical parameters and carefully measured. Fenoldopam will be started at 0.1 ug/kg/min. If, after 6 hrs there is no decrease in blood pressure, the dose will be increased to 0.2 ug/kg/min. This dose will be continued throughout the remainder of the study. A study of pediatric patients previously provided to the FDA showed no hypotension at a dose of 0.2 ug/kg/min. Fenoldopam will be started 12 hrs before the first dose of indomethacin and discontinued 12 hrs after the 3rd dose of indomethacin. Study samples will include both blood and urine. The primary outcome will be a reduction in renal dysfunction, as determined by creatinine and urine output over the course of treatment. Additional outcomes will include determination of known and novel metabolomic urine markers of renal dysfunction.

Hypotheses The investigators primary hypothesis is that fenoldopam reduces renal dysfunction associated with indomethacin administration for closure of patent ductus arteriosus in preterm infants. A secondary endpoint or measured outcome will be the determination of fenoldopam pharmacokinetics in the premature population. Lastly, the investigators hypothesize that urine and serum acute kidney injury (AKI) biomarkers will be superior to contemporary neonatal AKI definitions in their ability to identify renal injury. Specific Aims Evaluate the effect of fenoldopam on renal function in preterm infants administered indomethacin Determination of fenoldopam pharmacokinetic and pharmacodynamic profiles in preterm infants Define whether newly identified biomarkers of renal dysfunction are more sensitive markers of renal dysfunction following indomethacin than traditional markers including urine output and serum creatinine. Study design The study will be a prospective, blinded, randomized, placebo controlled trial. Fenoldopam will be started at 0.1 ug/kg/min. If, after 6 hrs there is no decrease in blood pressure, the dose will be increased to 0.2 ug/kg/min and continued throughout the remainder of the study. The previous study in pediatric patients showed no hypotension at a dose of 0.2 ug/kg/min. Fenoldopam will be started 12 hrs before the first dose of indomethacin and discontinued 12 hrs after the 3rd dose of indomethacin. Describe study population or sample material preterm infants born at less than or equal to 28 weeks gestation with patent ductus arteriosus in whom attempted medical closure with indomethacin is indicated as decided upon by the attending physician Sample size/power of primary endpoint Sample size is 20 patients in each of the two arms (fenoldopam vs placebo) based upon an improvement in serum creatinine by one standard deviation.

Infants in the Placebo arm will receive 0.9% sodium chloride (0.1 ml/hr). If, after 6 hrs there is not a clinically concerning decrease in blood pressure, as determined by attending physician, the rate of infusion (in this arm the placebo) will be increased to 0.2 ml/kg/hr. This rate will be continued throughout the remainder of the study.

Infants in the experimental arm will receive fenoldopam (60 ug/ml; 0.1 ml/hr to provide 0.1ug/kg/min). If, after 6 hrs there is not a clinically concerning decrease in blood pressure, as determined by attending physician, the rate of infusion will be increased to 0.2 ml/kg/hr (0.2 ug/kg/min for infants receiving fenoldopam). This rate will be continued throughout the remainder of the study.

Urine will be collected and measured in 6 hour increments beginning 6 hours prior to starting fenoldopam or placebo infusion. The first dose of indomethacin will be given 12 hours after starting fenoldopam or placebo. Two additional doses of indomethacin will be given 12 hours apart. Urine will continue to be collected and volume measured in 6 hour increments up to 24 hrs after the last dose of indomethacin. To summarize, urine will be collected and measured from time -6 hours to 0 hours. Fenoldapam or placebo will be initiated at time 0 hrs, indomethacin given at time 12, 24 and 36 hours, and urine collected and measured to time 60 hours.

66 hrs - from 6 hrs before beginning of fenoldopam or placebo infusion up to 24 hours after the last dose of indomethacin

Serum Levels of Fenoldopam During Infusion of the Drug and Following Discontinuation of the Drug Will be Measured by Liquid Chromatography and Mass Spectroscopy.

Blood samples for determination of serum fenoldopam levels will be obtained immediately prior to starting the infusion of fenoldopam (time 0 hour), continue through the 48 hour period of fenoldopam infusion and continue for an additional 12 hours after stopping the fenoldopam infusion.

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Serum creatinine will be measured immediately prior to first dose of indomethacin, immediately prior to the third dose of indomethacin (24 hr later) and 24 hours after the third dose of indomethacin

We will relate serum levels of fenoldopam to changes in urine volume over the duration of time of fenoldopam infusion and after discontinuation of infusion. This constitutes part of the pharmacodynamic analysis

We will relate serum levels of fenoldopam to serum creatinine values over the duration of time of fenoldopam infusion and after discontinuation of infusion. This constitutes part of the pharmacodynamic analysis

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Period from just prior to first dose of indomethacin (time point 12 hours) to 24 hours beyond last dose of indomethacin ( which is time point 60 hours). Thus, this aspect of study takes place between time point 12 hr and time point 60 hr, which is a 48 hour period

Inclusion Criteria: Gestational age at birth 23 0/7 to 27 6/7 weeks by best obstetrical dating No previous exposure to indomethacin Clinical determination to use indomethacin to attempt closure of PDA No known congenital abnormalities involving the kidneys, heart or lungs No preexisting renal dysfunction, defined as serum creatinine > 1.0 mg/dl, or urine output <1.0 ml/kg/hour over the previous 24 hours. Exclusion Criteria: Enrollment in concurrent study in which interventions may contribute confounding variables or have competing outcomes Infants with antenatally or postnatally diagnosed renal or urinary tract abnormalities Infants with umbilical cord or infant blood pH below 7.0 at any time before enrollment Attending physician unwilling to have infant participate in study Absence of informed consent