Clinical and economic impact of oral ondansetron for vomiting in a pediatric emergency department

The effect of oral ondansetron on QT interval in children with acute gastroenteritis; a retrospective observational study

Background

In mildly to moderately dehydrated patients with acute gastroenteritis (AGE), oral rehydration therapy (ORT) is the treatment of choice. Though ondansetron is a very effective antiemetics and leads to succeed ORT, there have been reports QT prolongation in patients using it. We investigated the effect of oral ondansetron on QT interval in mildly to moderately dehydrated children with AGE.

Methods

This retrospective observational study was conducted in a single pediatric emergency department (ED) of a tertiary university hospital. We collected the medical records of patients with a primary diagnosis of AGE who received oral ondansetron and underwent an electrocardiogram between January 2017 and June 2018. A pediatric emergency physician calculated the corrected QT interval (QTc) by Bazett’s method, and the calculations were reviewed by a pediatric cardiologist. QTc values before (preQTc) and after (postQTc) ondansetron administration were analyzed. ΔQTc was calculated as the change from preQTc to postQTc. We also investigated any cardiac complications from oral ondansetron.

Results

Total 80 patients were included. The mean age of the patients was 53.31 ± 32.42 months, and 45% were male. The mean dose of oral ondansetron was 0.18 ± 0.04 mg/kg. The mean interval from administration of ondansetron to performance of the electrocardiogram was 65 ± 26 min. The mean preQTc was 403.3 ± 24.0 ms, and the mean postQTc was 407.2 ± 26.7 ms. Two patients had a preQTc ≥460 ms, and one patient had a postQTc ≥460 ms. ΔQTc was ≥30 ms in seven patients (8.8%). No ΔQTc was ≥60 ms. No pre- or postQTc was ≥500 ms. No patient had a fatal cardiac arrhythmia after taking ondansetron.

Conclusion

Oral administration of a single dose of ondansetron in children with AGE did not cause high-risk QTc prolongation or fatal arrhythmia.

Protocol for a double blind, randomised placebo-controlled trial using ondansetron to reduce vomiting in children receiving intranasal fentanyl and inhaled nitrous oxide for procedural sedation in the emergency department (the FON trial)

INTRODUCTION

Intranasal fentanyl and nitrous oxide (N₂O) can be combined to create a non-parenteral procedural sedation regimen for children in the paediatric emergency department. This combination of intranasal fentanyl and N₂O provides effective pain relief for more painful procedures, but is associated with a higher incidence of vomiting than N₂O alone. Our aim is to assess whether ondansetron used preventatively reduces the incidence of vomiting associated with intranasal fentanyl and N₂O for procedural sedation compared with placebo.

METHODS AND ANALYSIS

This study is a double blind, randomised placebo-controlled superiority trial. This is a single-centre trial of 442 children aged 3-18 years presenting to a tertiary care Paediatric Emergency Department at the Royal Children's Hospital (RCH), Melbourne, Australia, requiring procedural sedation with intranasal fentanyl and N₂O. After written consent, eligible participants are randomised to receive ondansetron or placebo along with intranasal fentanyl, 30-60 min prior to N₂O administration. The primary outcome is vomiting during or up to 1 hour after procedural sedation. Secondary outcomes include: number of vomits and retching during procedural sedation, vomiting 1-24 hours after procedural sedation, procedural sedation duration and associated adverse events, procedure abandonment, parental satisfaction and the value parents place on the prevention of vomiting. This trial will allow refinement of a non-parenteral sedation regimen for children requiring painful procedures.

ETHICS AND DISSEMINATION

This study has ethics approval at the RCH, Melbourne, protocol number 36174. The results from this trial will be submitted to conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12616001213437).

Management of Diarrhoeal Dehydration in Childhood: A Review for Clinicians in Developing Countries

The survival of a child with severe volume depletion at the emergency department depends on the competency of the first responder to recognize and promptly treat hypovolemic shock. Although the basic principles on fluid and electrolytes therapy have been investigated for decades, the topic remains a challenge, as consensus on clinical management protocol is difficult to reach, and more adverse events are reported from fluid administration than for any other drug. While the old principles proposed by Holliday and Segar, and Finberg have stood the test of time, recent systematic reviews and meta-analyses have highlighted the risk of hyponatraemia, and hyponatraemic encephalopathy in some children treated with hypotonic fluids. In the midst of conflicting literature on fluid and electrolytes therapy, it would appear that isotonic fluids are best suitable for the correction of hypotonic, isonatraemic, and hypernatraemic dehydration. Although oral rehydration therapy is adequate to correct mild to moderate isonatraemic dehydration, parenteral fluid therapy is safer for the child with severe dehydration and those with changes in serum sodium. The article reviews the pathophysiology of water and sodium metabolism and, it uses the clinical case examples to illustrate the bed-side approach to the management of three different types of dehydration using a pre-mixed isotonic fluid solution (with 20 or 40 mmol/L of potassium chloride added depending on the absence or presence of hypokalemia, respectively). When 3% sodium chloride is unavailable to treat hyponatraemic encephalopathy, 0.9% sodium chloride becomes inevitable, albeit, a closer monitoring of serum sodium is required. The importance of a keen and regular clinical and laboratory monitoring of a child being rehydrated is emphasized. The article would be valuable to clinicians in less-developed countries, who must use pre-mixed fluids, and who often cannot get some suitable rehydrating solutions.