A Randomised Multiple Centre Trial of Conservative versus Liberal Fluid administration for Children Receiving a Kidney Transplant (LIMITS)

BACKGROUND In current practice, large fluid volumes are administered to most children following kidney transplant (median > 4 x typical intravenous fluid prescriptions). Up to 52% experience fluid overload related complications. Too little fluid can delay transplant function.

Current fluid guidelines are not evidence based, and the optimal amount of fluid for children after transplant is not known.

RESEARCH QUESTION [Population] In children receiving kidney transplants, [Intervention] is relative limitation of fluid volume administered superior to [Comparator] usual liberal fluid volume administration, in terms of [Outcome] days at home up to 30 days after transplant?

DESIGN LIMITS is a pragmatic multi-centre, open randomised controlled trial with internal pilot phase and integrated economic evaluation.

SETTING All ten UK children s kidney transplant centres POPULATION Children under 18-years of age receiving a kidney only transplant in UK.

INTERVENTION Fluid volume administration capped at maximum 150ml/m2/hour for no longer than 18 hours following transplant, reduced to a fixed daily target of maximum 1.5 litres/m2/day thereafter. No specific urine output will be targeted. No diuretics to be administered. COMPARATOR Target urine output >2ml/kg/hour.

Fluid administered to replace urine output + insensible losses for at least 48 hours. Diuretics per the clinical team s usual practice. PRIMARY OUTCOME Days at home in the first 30 days after kidney transplant.

OTHER OUTCOMES Patient-reported experience of transplant hospital stay Systemic hypertension (systolic blood pressure above the 95th centile for age and height on 2 consecutive days) within 7 days after transplant Pulmonary oedema on chest x-ray within 7 days after transplant Severe acute hyponatraemia (plasma sodium concentration <130mmol/l) within 7 days after transplant Blood transfusion administration within 7 days after transplant Transplant thrombosis in the post-operative period leading to graft failure Delayed transplant function (dialysis within the first 7 days after transplant) Transplant function measured by estimated glomerular filtration rate at 3 months post-transplant TIMELINES Total duration 36 months (HRA approval 1-3; site approvals and training 4-9; patient recruitment 7-30; follow-up 31-33; analysis and dissemination 34&ndash;36).

DISSEMINATION We will communicate results to patients and parents with our patient co-applicants, present results at national and international meetings and publish them in a widely read medical journal.

IMPACT This research has the potential to change current practice of administering very large volumes of fluid to children after kidney transplant.

This would inform national guidance to make perioperative care safer, reduce complications of fluid overload and improve children s experience of transplantation. It may improve children s recovery time and free up capacity in children s kidney units.