Furosemide and ethacrynic acid: risk factors for the occurrence of serum electrolyte abnormalities and metabolic alkalosis in newborns and infants

Hypochloremia Secondary to Diuretics in Preterm Infants: Should Clinicians Pay Close Attention?

Diuretic therapy, commonly used in the newborn intensive care unit, is associated with a variety of electrolyte abnormalities such as hyponatremia, hypokalemia, and hypochloremia. Hypochloremia, often ignored, is associated with significant morbidities and increased mortality in infants and adults. Clinicians respond in a reflex manner to hyponatremia than to hypochloremia. Hypochloremia is associated with nephrocalcinosis, hypochloremic alkalosis, and poor growth. Besides, the diuretic resistance associated with hypochloremia makes maintaining chloride levels in the physiological range even more logical. Since sodium supplementation counters the renal absorption of calcium and lack of evidence for spironolactone role in diuretic therapy for bronchopulmonary dysplasia (BPD), alternate chloride supplements such as potassium or arginine chloride may need to be considered in the management of hypochloremia due to diuretic therapy. In this review, we have summarized the current literature on hypochloremia secondary to diuretics and suggested a pragmatic approach to hypochloremia in preterm infants.

Acetazolamide Therapy for Hypochloremic Metabolic Alkalosis in Pediatric Patients With Heart Disease

BACKGROUND

Pediatric patients with heart disease are often treated with high doses of diuretics, which can lead to hypochloremic metabolic alkalosis. There are no data in children regarding the efficacy and safety of acetazolamide to treat hypochloremic metabolic alkalosis.

METHODS

Patients from January 2004 to June 2005 who received acetazolamide were identified. Inclusion criteria were: age less than 18 years, being a cardiology patient, diuretics use, and had received a 3-day course of acetazolamide. Demographic information was collected along with serum electrolytes, serum creatinine/blood urea nitrogen, urine output, pH, acid-base excess, concurrent medications, cardiac lesion/surgery, and incidence of adverse effects. Efficacy of acetazolamide was determined by comparing variables before and after the 3-day course. Statistical comparisons were made using Student's t-test.

RESULTS

A total of 28 patients were identified, 7 of whom received oral acetazolamide, 21 intravenous acetazolamide. Patients were a median of 2.5 (range, 0.3-20) months of age, and 57% (17/28) were female. Seventy-one percent of the cohort received acetazolamide after cardiac surgery. There was no significant difference in any electrolyte, blood urea nitrogen, or serum creatinine from baseline, except for serum bicarbonate, which decreased (36.2 +/- 4.6 vs. 30.9 +/- 4.5 mmol/L, P < 0.001), and chloride, which increased (91.1 +/- 6.8 vs. 95.4 +/- 6.2, P < 0.03). Acid-base excess values and pH decreased during therapy in patients who had the laboratory values drawn (n = 22). No change in urine output at 8 hours (5.2 +/- 2.3 vs. 4.9 +/- 2.3 mL/kg/hr, P = 0.6) or 24 hours (4.7 +/- 1.5 vs. 4.3 +/- 1.4 mL/kg/hr, P = 0.18) occurred after administration of acetazolamide.

CONCLUSION

Acetazolamide was safely used in pediatric patients with heart disease to lower serum bicarbonate and acid-base excess values and raise chloride values in hypochloremic metabolic alkalosis.

Diurétiques et prématuré

Diuretics are frequently used in preterm infants in various situations such as patent ductus arteriosus, respiratory distress syndrome, bronchopulmonary dysplasia or neonatal renal insufficiency. However, the beneficial effects reported in the literature are usually transient, without any obvious effect on important parameters such as duration of oxygen dependency, ventilator dependency, length of hospital stay, long-term outcome, or mortality. Moreover, these drugs may induce water-electrolyte disorders especially when used for a long-term period. Thus, we recommend a systematic analysis of the beneficial/risk ratio before any use of these drugs.

The kidney in acid-base balance

The practitioner's approach to the pediatric patient with metabolic acidosis begins with calculation of the serum anion gap, which allows the clinician to place the patient in one of two categories of acid-base disturbance: a normal anion gap acidosis or high anion gap acidosis. Likewise, the patient with metabolic alkalosis can be categorized by urinary chloride concentration and the response to chloride replenishment as either chloride-responsive or chloride-resistant. The disease states associated with each category are reviewed in this article.

Pharmacology of diuretics in the newborn

Diuretics are used in various conditions with fluid overload. Their efficacy in the management of congestive heart failure is well documented. In contrast, the indication of diuretics in chronic lung disease and central nervous system disorders of the newborn have not been clearly established. Substantial pharmacologic knowledge of diuretics in the young infant remains to be described. Most investigations on diuretics in the sick newborn infant have examined furosemide. In contrast, the pharmaco-dynamics, pharmacokinetics, clinical indications, and toxicity of other diuretics used in the newborn require considerable further evaluation. Future studies using a combination of diuretics, acting at different segments of the nephron, also may provide newer therapeutic modalities to overcome or prevent the development of frequently observed tolerance to diuretics, as well as to treat refractory edema.