FiSh: Combined feasibility and external pilot study to inform the design and conduct of the Fluids in Shock


Usual treatment when a child arrives at a hospital Emergency Department (ED) with a severe infection and shock is to give liberal amounts of fluid injected into a vein (fluid bolus therapy). However, this is based on weak evidence. A group of doctors and researchers came together to propose the FiSh (Fluids in Shock) study, aiming to find out whether giving less fluid is beneficial.


Before a large trial is carried out, it is important to answer the question ‘can this trial be done?’. The FiSh feasibility study aimed to do this. Firstly, we conducted an interview study asking about parents’ views on the proposed study and the acceptability of research without prior consent (RWPC) – used in previous emergency studies. Secondly, we conducted a pilot study (small version of the FiSh study) to test important factors, such as number of children recruited and if doctors and nurses followed the trial protocol properly. Parents of children and hospital staff who participated in the pilot were interviewed for feedback.


In the initial interview study the 21 parents interviewed supported both the FiSh study and the use of RWPC. In the pilot study, 75 children were recruited from 13 hospitals in England. Children were randomly allocated to receive smaller or liberal (currently recommended volume) fluid boluses. Recruitment was close to the expected level (one patient per hospital per month) and hospitals usually gave the correct amount of fluid in each group. However, patients were a lot less sick than expected and the majority only required one fluid bolus to show improvement. Overall parents and hospital staff supported the study.


Even though both the interview study and pilot study were carried out successfully, as the children recruited were not as unwell as expected, the trial as currently designed, is not feasible.

Who led the study?

Dr David Inwald, Imperial College Healthcare NHS Trust, London

This study was funded by the National Institute for Health Research (NIHR) – Health Technology Assessment (HTA) Programme (Project: 13/04/105)


Woolfall K, O'Hara C, Deja E, Canter R, Khan I, Mouncey P, Carter A, Jones N, Watkins J, Lyttle MD, Tume L, Agbeko R, Tibby SM, Pappachan J, Thorburn K, Rowan KM, Peters MJ, Inwald D. Parents' prioritised outcomes for trials investigating treatments for paediatric severe infection: a qualitative synthesis. Arch Dis Child 2019; .

O'Hara CB, Canter RR, Mouncey PR, Carter A, Jones N, Nadel S, Peters MJ, Lyttle MD, Harrison DA, Rowan KM, Inwald D, Woolfall K. A qualitative feasibility study to inform a randomised controlled trial of fluid bolus therapy in septic shock. Arch Dis Child 2018; 103(1):28-32.

Inwald DP, Canter R, Woolfall K, Mouncey P, Zenasni Z, O'Hara C, Carter A, Jones N, Lyttle MD, Nadel S, Peters MJ, Harrison DA, Rowan KM. Restricted fluid bolus volume in early septic shock: results of the Fluids in Shock pilot trial. Arch Dis Child 2018; .