REstrictive versus StandarD FlUid Management in Mechanically Ventilated ChildrEn Admitted to PICU: study protocol for a pilot randomised controlled trial (REDUCE-1).

introductionIntravenous fluid therapy is the most common intervention in critically ill children. There is an increasing body of evidence questioning the safety of high-volume intravenous fluid administration in these patients. To date, the optimal fluid management strategy remains unclear. We aimed to test the feasibility of a pragmatic randomised controlled trial comparing a restrictive with a standard (liberal) fluid management strategy in critically ill children. METHODS AND ANALYSIS: Multicentre, binational pilot, randomised, controlled, open-label, pragmatic trial. Patients <18 years admitted to paediatric intensive care unit and mechanically ventilated at the time of screening are eligible. Patients with tumour lysis syndrome, diabetic ketoacidosis or postorgan transplant are excluded.

interventions1:1 random assignment of 154 individual patients into two groups-restrictive versus standard, liberal, fluid strategy-stratified by primary diagnosis (cardiac/non-cardiac). The intervention consists of a restrictive fluid bundle, including lower maintenance fluid allowance, limiting fluid boluses, reducing volumes of drug delivery and initiating diuretics or peritoneal dialysis earlier. The intervention is applied for 48 hours postrandomisation or until discharge (whichever is earlier). ENDPOINTS: The number of patients recruited per month and proportion of recruited to eligible patients are feasibility endpoints. New-onset acute kidney injury and the incidence of clinically relevant central venous thrombosis are safety endpoints. Fluid balance at 48 hours after randomisation is the efficacy endpoint. Survival free of paediatric intensive care censored at 28 days is the clinical endpoint. ETHICS AND DISSEMINATION: Ethics approval was gained from the Children's Health Queensland Human Research Ethics Committee (HREC/21/QCHQ/77514, date: 1 September 2021), and University of Zurich (2021-02447, date: 17 March 2023). The trial is registered with the Australia New Zealand Clinical Trials Registry (ACTRN12621001311842). Open-access publication in high impact peer-reviewed journals will be sought. Modern information dissemination strategies will also be used including social media to disseminate the outcomes of the study. TRIAL REGISTRATION NUMBER: ACTRN12621001311842. PROTOCOL VERSION/DATE: V5/23 May 2023.