Effect of a modified fluid therapy on renal function during indomethacin therapy for persistent ductus arteriosus

Furosemide for symptomatic patent ductus arteriosus in indomethacin-treated infants

BACKGROUND

Inhibition of prostaglandin synthesis mediates closure of the ductus arteriosus and renal side effects after indomethacin administration. Because furosemide increases prostaglandin production, it could potentially help prevent indomethacin-related toxicity but also decrease ductal response to indomethacin.

OBJECTIVES

The primary objectives of this review were to assess (1) whether furosemide affects the incidence of failure of ductal closure after indomethacin and that of indomethacin-related toxicity and (2) the effect of furosemide on mid-term and long-term outcome. The secondary objective was to determine whether the effect of furosemide on renal function and water balance depends on prior extracellular volume (assessed by blood urea nitrogen [BUN]/creatinine ratio).

SEARCH STRATEGY

We searched electronic databases (Medline, Embase and Cochrane) and selected abstract books, without language restriction.

SELECTION CRITERIA

We selected studies with (1) random allocation to either indomethacin alone or indomethacin and furosemide and (2) analysis of either short-term risk-benefit ratio of furosemide, mid- or long-term outcome, or the relationship between extracellular volume at study entry and changes in renal function.

DATA COLLECTION AND ANALYSIS

We assessed studies for possible bias and for quality of assessment of ductal patency. We assessed categorical variables using relative risk and absolute risk reduction. We assessed the effects of furosemide on renal function and fluid balance by comparing changes from baseline in the treatment group with those in controls. Subsets were determined a priori based on BUN/creatinine ratio at study entry.

MAIN RESULTS

All 3 studies fulfilling the entry criteria had limitations, including possible or definite bias. There was substantial heterogeneity among studies. Furosemide administration did not significantly increase the risk of failure of ductal closure; however, sample size was insufficient to rule out even a 31% increase. In the subset with initial BUN/creatinine ratio > 20 mg/mg, 2 of 18 patients receiving furosemide could not complete a 3-dose course of indomethacin because of toxicity. Minimal or no information was available about any of the other main outcome variables. Furosemide increased urine output regardless of the initial BUN/creatinine ratio, leading to a 5% weight loss during a 3-dose course, an undesired effect in patients with initial BUN/creatinine ratio > 20 mg/mg. Furosemide increased creatinine clearance only in patients with initial BUN/creatinine ratio <20 mg/mg.

REVIEWER'S CONCLUSIONS

There is not enough evidence to support the administration of furosemide to premature infants treated with indomethacin for symptomatic patent ductus arteriosus. Furosemide appears to be contraindicated in the presence of dehydration in those infants.

Effects of highly overdosed indomethacin in a preterm infant with symptomatic patent ductus arteriosus

We describe a preterm infant with severe idiopathic respiratory distress syndrome (iRDS, hyaline membrane disease) who needed artificial ventilation with high inspiratory pressure, high frequencies, 100% oxygen and developed a symptomatic patent ductus arteriosus (sPDA) in the course of the disease. The infant was given indomethacin to induce constriction of sPDA. Due to an error in drug dilution the patient received a 100-fold overdose of indomethacin. Compared to the normal study protocol side-effects such as renal failure were not observed probably due to sufficient fluid intake and good clinical condition prior to treatment and to the rapid and persistent ductal closure.

Special needs of the newborn infant in fluid therapy

The preterm baby, although less able to tolerate high fluid and solute loads, has a remarkable ability to adapt to a rather broad range of environmental challenges, and thus renal function in the preterm infant should no longer be considered impaired. Lower rather than higher fluid administration is the current trend in neonatal care because it is safer and more physiologic. Although changes in body weight over time provide a good indicator of water balance, determination of plasma and urine electrolytes and tonicity are also essential in the monitoring of fluid therapy in preterm infants.