Enhancement of diuresis with metolazone in infant paediatric cardiac intensive care patients

Enteral Sodium Chloride Supplementation and Fluid Balance in Children Receiving Diuretics

The use of sodium chloride (NaCl) supplementation in children being prescribed diuretics is controversial due to concerns that supplementation could lead to fluid retention. This is a single-center retrospective study in which fluid balance and diuretic dosing was examined in children prescribed enteral NaCl supplements for hyponatremia while receiving loop diuretics. The aim of this study was to determine whether significant fluid retention occurred with the addition of NaCl. Fifty-five patients with 68 events were studied. The median age was 5.2 months, and 82% were hospitalized for cardiac disease. Daily fluid balance the seven days prior to NaCl supplementation was lower than the seven days after, with measurement of: median 17 mL/kg/day (7–26) vs. 22 mL/kg/day (13–35) (p = 0.0003). There was no change in patient weight after supplementation (p = 0.63). There was no difference in the median loop diuretic dose before and after supplementation, with the diuretic dose in furosemide equivalents of 3.2 mL/kg/day (2.3–4.4) vs. 3.2 mL/kg/day (2.2–4.7) (p = 0.50). There was no difference in the proportion of patients receiving thiazide diuretics after supplementation (56% before vs. 50% after (p = 0.10)). NaCl supplementation in children receiving loop diuretics increased calculated fluid balance, but weight was unchanged, and this was not associated with an increase in diuretic needs, suggesting clinicians did not consider the increase in fluid balance to be clinically significant.

A systematic review of the evidence supporting post-operative diuretic use following cardiopulmonary bypass in children with Congenital Heart Disease

BACKGROUND

Paediatric cardiac surgery on cardiopulmonary bypass induces substantial physiologic changes that contribute to post-operative morbidity and mortality. Fluid overload and oedema are prevalent complications, routinely treated with diuretics. The optimal diuretic choice, timing of initiation, dose, and interval remain largely unknown.

METHODS

To guide clinical practice and future studies, we used PubMed and EMBASE to systematically review the existing literature of clinical trials involving diuretics following cardiac surgery from 2000 to 2020 in children aged 0-18 years. Studies were assessed by two reviewers to ensure that they met eligibility criteria.

RESULTS

We identified nine studies of 430 children across four medication classes. Five studies were retrospective, and four were prospective, two of which included randomisation. All were single centre. There were five primary endpoints - urine output, acute kidney injury, fluid balance, change in serum bicarbonate level, and required dose of diuretic. Included studies showed early post-operative diuretic resistance, suggesting higher initial doses. Two studies of ethacrynic acid showed increased urine output and lower diuretic requirement compared to furosemide. Children receiving peritoneal dialysis were less likely to develop fluid overload than those receiving furosemide. Chlorothiazide, acetazolamide, and tolvaptan demonstrated potential benefit as adjuncts to traditional diuretic regimens.

CONCLUSIONS

Early diuretic resistance is seen in children following cardiopulmonary bypass. Ethacrynic acid appears superior to furosemide. Adjunct diuretic therapies may provide additional benefit. Study populations were heterogeneous and endpoints varied. Standardised, validated endpoints and pragmatic trial designs may allow investigators to determine the optimal diuretic, timing of initiation, dose, and interval to improve post-operative outcomes.

Lower-Dose, Intravenous Chlorothiazide Is an Effective Adjunct Diuretic to Furosemide Following Pediatric Cardiac Surgery

OBJECTIVES

Postoperative fluid overload is ubiquitous in neonates and infants following operative intervention for congenital heart defects; ineffective diuresis is associated with poor outcomes. Diuresis with furosemide is widely used, yet there is often resistance at higher doses. In theory, furosemide resistance may be overcome with chlorothiazide; however, its efficacy is unclear, especially in lower doses and in this population. We hypothesized the addition of lower-dose, intravenous chlorothiazide following surgery in patients on high-dose furosemide would induce meaningful diuresis with minimal side effects.

METHODS

This was a retrospective, cohort study. Postoperative infants younger than 6 months, receiving high-dose furosemide, and given lower-dose chlorothiazide (1-2 mg/kg every 6-12 hours) were identified. Diuretic doses, urine output, fluid balance, vasoactive-inotropic scores, total fluid intake, and electrolyte levels were recorded.

RESULTS

There were 73 patients included. The addition of lower-dose chlorothiazide was associated with a significant increase in urine output (3.8 ± 0.18 vs 5.6 ± 0.27 mL/kg/hr, p < 0.001), more negative fluid balance (16.1 ± 4.2 vs -25.0 ± 6.3 mL/kg/day, p < 0.001), and marginal changes in electrolytes. Multivariate analysis was performed, demonstrating that increased urine output and more negative fluid balance were independently associated with addition of chlorothiazide. Subgroup analysis of 21 patients without a change in furosemide dose demonstrated the addition of chlorothiazide significantly increased urine output (p = 0.03) and reduced fluid balance (p < 0.01), further validating the adjunct effects of chlorothiazide.

CONCLUSION

Lower-dose, intravenous chlorothiazide is an effective adjunct treatment in postoperative neonates and infants younger than 6 months following cardiothoracic surgery.

Guidelines for Diuretic Utilization Reduce High Charge Medications

Decreasing practice variation and following evidence-based clinical guidelines improve patient outcomes and often reduce cost. Essentially all postsurgical cardiac patients require diuretics. The approach to diuresis in the pediatric cardiothoracic intensive care unit (CTICU) is not standardized. Our objective was to develop and implement guidelines for diuretic utilization in the CTICU to reduce high charge medication utilization while maintaining the delivery of high-quality care.