6454 Rates of salbutamol toxicity in children referred to a paediatric critical care transport team

Objectives Intravenous (IV) salbutamol is a second line treatment for children with acute wheeze or asthma, after initial treatment with inhaled or nebulised bronchodilators.¹ It can be given as a bolus or an infusion and is an effective bronchodilator but has dose dependent side effects including hypokalaemia, nausea, arrhythmia and lactic acidosis. In adults, the maximum recommended salbutamol infusion rate is 20micrograms/min.² For children, the recommended rate is 1–2microgram/kg/min and up to 5 microgram/kg/min.¹ Despite their smaller size, infusion rates in children can therefore be several times the maximum adult dose. We undertook a case-note review of children referred to a regional paediatric critical care transport team (PCCT) to determine whether there was an association between IV salbutamol dosing and rates of toxicity. Methods Children referred to the PCCT between August 2020 and July 2023 with a diagnosis of 'asthma' or 'wheeze' were identified and notes of those given IV salbutamol reviewed. Data recorded included weight, maximum salbutamol infusion rate, biochemical markers of toxicity (lactate, potassium, glucose) and additional medical treatment. Toxicity was defined as tachycardia plus one or more of: increased lactate (>2mmol/L), hypokalaemia (<3.5mmol/L) or consistent symptoms (sweatiness, vomiting, jitteriness/shakiness and agitation/irritability). The relationships between categorical variables were analysed using the chi-square test. Results 261 children were identified, of whom 77 were treated with IV salbutamol. 58 (75.3%) met the definition of salbutamol toxicity. In 9 children the infusion rate was not recorded. 18 were transported to a tertiary centre and 59 stayed in the referring hospital. Of those on ≤20 micrograms/min salbutamol, 15/28 (54%) were toxic; of those on >20 micrograms/min this was 36/40 (90%) p<0.01. There was no difference in rates of toxicity by salbutamol infusion dose in micrograms/kg/minute or between those given or not given an IV salbutamol bolus (table 1). Conclusion Most children referred to the PCCT with wheeze or asthma were not treated with IV salbutamol, however, of those who were, most had signs of salbutamol toxicity. In our population, toxicity rates were significantly higher when it was administered at a rate over the normal adult maximum rather than at higher rates per kg body weight. A pharmacokinetic study in children found that, following a salbutamol bolus, a rate of only 0.5 micrograms/kg/min achieved optimal bronchodilation.³ Although our sample size is relatively small, our data suggest that clinicians should consider capping the maximum salbutamol infusion rates at considerably below the current recommended maximum. References British Thoracic Society/SIGN Guideline for the Management of Asthma, v 158, July 2019. https://bnf.nice.org.uk/drugs/salbutamol/#indications-and-dose Walsh S, Pan S, Sheng Y OSTRICH Study Group, et al. Optimising intravenous salbutamol in children: a phase 2 study, Archives of Disease in Childhood 2023;108:316–322.