BMJ Open. 2018 Jan 23;8(1):e019627. doi: 10.1136/bmjopen-2017-019627.

# What fluids are given during air ambulance treatment of patients with trauma in the UK, and what might this mean for the future? Results from the RESCUER observational cohort study.

Naumann D, Hancox J, Raitt J, Smith I, Crombie N, Doughty H, Perkins G, Midwinter M; RESCUER Collaborators.

Collaborators: Evans D, Conway J, Leech C, Lewis S, Church N, Mickwitz C, Pountney A, Bell F, Shewan J, Hyde P, Eddie M, Walker M, Hindson R, Wilson A, Elms S, Hood C, Blackham J, Grier S, Brown V, Irwin R, Clarke N, Corfield A, Cadman A, Evans D, Conway J, Leech C, Lewis S, Church N, Mickwitz C, Pountney A, Bell F, Shewan J, Hyde P, Eddie M, Walker M, Hindson R, Wilson A, Elms S, Hood C, Blackham J, Grier S, Brown V, Irwin R, Clarke N, Corfield A, Cadman A.

OBJECTIVES: We investigated how often intravenous fluids have been delivered during physician-led prehospital treatment of patients with hypotensive trauma in the UK and which fluids were given. These data were used to estimate the potential national requirement for prehospital blood products (PHBP) if evidence from ongoing trials were to report clinical superiority.

SETTING: The Regional Exploration of Standard Care during Evacuation Resuscitation (RESCUER) retrospective observational study was a collaboration between 11 UK air ambulance services. Each was invited to provide up to 5 years of data and total number of taskings during the same period.

PARTICIPANTS: Patients with hypotensive trauma (systolic blood pressure <90 mm Hg or absent radial pulse) attended by a doctor.

PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was the number of patients with hypotensive trauma given prehospital fluids. Secondary outcomes were types and volumes of fluids. These data were combined with published data to estimate potential national eligibility for PHBP.

RESULTS: Of 29 037 taskings, 729 (2.5%) were for patients with hypotensive trauma attended by a physician. Half were aged 21-50 years; 73.4% were male. A total of 537 out of 729 (73.7%) were given fluids. Five hundred and ten patients were given a single type of fluid; 27 received >1 type. The most common fluid was 0.9% saline, given to 486/537 (90.5%) of patients who received fluids, at a median volume of 750 (IQR 300-1500) mL. Three per cent of patients received PHBP. Estimated projections for patients eligible for PHBP at these 11 services and in the whole UK were 313 and 794 patients per year, respectively.

CONCLUSIONS: One in 40 air ambulance taskings were manned by physicians to retrievepatients with hypotensive trauma. The most common fluid delivered was 0.9% saline. If evidence justifies universal provision of PHBP, approximately 800 patients/year would be eligible in the UK, based on our data combined with others published. Prospective investigations are required to confirm or adjust these estimations.