Developing a Digital Handover Application for Paramedics to Provide a Personalized Approach to Pre-hospital Stratification for Out of Hospital Cardiac Arrest

Design: Prospective observational cohort study enrolling OOHCA patients across London in a pre-hospital setting

Study Protocol: Patients with OOHCA and ROSC will be recruited from the community into the study by London Ambulance Service NHS Trust (LAS). LAS has -40 Advanced Paramedic Practitioners in Critical Care (APP-CC) who have a range of specialist skills including airway management and focused ultrasound and attend to over 1500 OOHCAs/year.

Point of Care pH test: The recruited participants will have point of care pH testing performed using the CG4+ iStat system (Abbott Vascular, Illinois, U.S.A.). The test requires 2ml of venous blood and can provide blood results within minutes. The device and blood taking system have received CE marking and are already in routine use across the NHS. Once the blood results are received, the blood sample and testing system are discarded in a routine manner.

Standard Care: Participants will then be conveyed to either the local emergency department or to a HAC based on current routine protocols. Patients will be treated in a routine manner after reaching secondary care in accordance with local and national guidance with no change in care based on this study.

Power calculation: In 2019, APP-CCs from LAS attended to -700 OOHCA patients with ROSC. Assuming 60% recruitment, we could comfortably envisage -500 patients to be recruited in a 15 month period. From previous data, we can expect approximately 60% of the patients (n=300) to have a CPC score of 3-5 on hospital discharge. This would be of a similar size to the dataset used to derive the original score, which gave good levels of accuracy in model performance measures.