Initial experience with fenoldopam after cardiac surgery in neonates with an insufficient response to conventional diuretics

Objective: Fenoldopam, a selective dopamine-1 receptor agonist, causes systemic vasodilation and increased renal blood flow and tubular sodium excretion. We hypothesized that urine output would improve when fenoldopam was added to conventional diuretic therapy after neonatal cardiopulmonary bypass. Design: Retrospective cohort study using a time-series design. Setting: Pediatric cardiac intensive care unit. Patients: All neonates who received fenoldopam to promote diuresis after cardiac surgery requiring cardiopulmonary bypass from February 2002 through December 2004. Interventions: Fenoldopam infusion for inadequate urine output despite conventional diuretics. Measurements: Demographics, diagnostic information, and surgical procedures were recorded. Urine output, fluid balance, inotrope scores, diuretic doses, and other clinical variables that may influence diuresis were recorded for the 24-hr period immediately preceding fenoldopam initiation and during the initial 24 hrs of drug administration. Main Results: A total of 25 neonates received fenoldopam to promote diuresis after the modified Norwood (n = 14), arterial switch (n = 4), or other operations (n = 7). Heart rate, conventional diuretic dosing, and fluid intake were similar during the 24-hr periods of conventional therapy and fenoldopam use (p = not significant for all), whereas inotrope scores decreased during the study (p = .021). There was a small but statistically significant increase in blood pressure during the 48-hr study period. Median urine output was 3.6 mL·kg^-1·hr^-1 (range, 0.2-7.2 mL·kg^-1·hr^-1) during the 24-hr period of conventional therapy and 5.8 mL·kg^-1·hr^-1 (range, 1.6-11.7 mL·kg^-1·hr^-1) during the initial 24 hrs of fenoldopam administration (Wilcoxon's signed-rank test, p = .001). Conclusions: Fenoldopam may improve urine output in neonates who are failing to achieve an adequate negative fluid balance despite conventional diuretic therapy after cardiac surgery and cardiopulmonary bypass. This study is limited by its retrospective design and the possibility that urine output improved spontaneously during the treatment period. A randomized, placebo-controlled clinical trial will be required to confirm these findings.