Title: Evaluation of the Valsalva Assist Device for the pre-hospital Emergency treatment of Supra-Ventricular Tachycardia [EVADE SVT] A Randomised Controlled Trial
Funder: Department of Health and Social Care

Abstract: Research question: Does routine ambulance service access to a simple device (Valsalva Assist Device (VAD)) to deliver a Valsalva Manoeuvre (VM) strain, in adult patients with attacks of Supraventricular Tachycardia (SVT), decrease the percentage of patients that are conveyed to hospital compared to current standard care? Background: SVT is a common tachyarrhythmia in people worldwide, with episodes resulting in rapid, unpleasant heart palpitations in often otherwise healthy individuals. Patients with SVT are often initially attended by ambulance services. International resuscitation and ambulance guidelines recommend emergency treatment of SVT with a Valsalva Manoeuvre (VM), a very safe physical treatment that can terminate the episode. However the VM is rarely effective in current pre-hospital practice, resulting in over 90% of patients being conveyed to hospital. A modified VM with a controlled strain pressure has been shown to significantly improve this treatment and a simple strain resistance device (VAD) might help ambulance clinicians better deliver this evidence based therapy. Aims and objectives: To determine whether routine access to the VAD will enable ambulance clinicians to provide a more effective VM and reduce the percentage of patients that are conveyed to hospital compared to the current standard VM which typically utilises blowing on a syringe to generate the VM strain. Methods: In light of detailed feasibility work, patient feedback and the significant challenges of conducting research in the pre-hospital setting, we propose an efficient, pragmatic and definitive, stepped-wedge cluster randomised controlled trial to see if the availability of the VAD and its instructions (intervention), to treat adult patients presenting to ambulance clinicians with SVT, can reduce hospital conveyance compared to current standard practice (control). The study would be conducted within one large ambulance trust in South West England, during routine care by usual treating clinicians, using routinely collected electronic data. Gradual introduction of VAD availability into the ambulance service, according to a planned randomised schedule would be accompanied by the collection of routine anonymous data for all eligible adult patients treated with a VM for SVT by ambulance clinicians unless the patient opted out. Timelines for delivery: We aim to commence the study in October 2021 lasting for 30 months with a recruitment period of 20 months and completion of the project by 31/03/2024. Anticipated impact and dissemination: Improving ambulance service SVT treatment and rates of hospital conveyance would have important benefits for patients, the ambulance service and wider health care provision. If routine use of the VAD to treat SVT facilitated earlier cardioversion and avoidance of hospital transfer, this would reduce the duration of patients symptoms and disruption to their lives. It would also save ambulance and emergency department services time for other emergencies, reducing waiting times and crowding. Dissemination of the study findings would be through high profile academic and commercial means. A reduction in conveyance rates of the size for which the study is powered has the potential to save the NHS money and the commercial opportunities gained through wider use of the device could support UK business and employment.

Lay abstract: A common heart problem called Supraventricular tachycardia (SVT) can cause the heart to suddenly start beating very quickly. This causes palpitations and makes patients feel frightened and unwell. People with an episode of SVT are often first seen by ambulance service staff. Ambulance service guidelines recommend a simple, safe, physical treatment called the Valsalva manoeuvre (VM) to get the heart beat back to normal. This involves a strain whilst blowing (like trying to inflate a stiff balloon), often done by blowing into an empty syringe. If the manoeuvre is successful, patients feel immediately better, do not always need to be taken to hospital and can see their GP at another time to plan further care. Unfortunately, the VM often doesn't work and so most patients are taken to hospital where they may need strong, unpleasant drugs to correct their heart beat. However, blowing into a simple, easy to use, safe and approved product, the Valsalva Assist Device (VAD), provided by ambulance staff, might help patients do a better VM and avoid emergency hospital admission and drug treatment. The device, which has its own instructions, can be given to patients to keep and use themselves in case the SVT happens again, instead of the syringe. Patients, who have helped us design and run this study, tell us they really value feeling better as soon as possible and avoiding going to hospital if not needed. The other benefits of not taking people to hospital are that the ambulance can go to other patients sooner and hospitals have fewer emergency patients to see, with more time and space for others. We plan to introduce the device into normal ambulance service care, (in a controlled way), to see if this can reduce the number of SVT patients who are taken to hospital. Only patients who would normally be treated with a VM would be included and only routine, anonymous data collected. It is just the way in which the VM strain is being done that will change; the rest of the patient s care will be the same as normal. However, we will also give patients written information about their condition and details of the study including how to opt out of having their data used, after they have been treated, should they wish. If our study shows a benefit to patients, the ambulance service could continue to use the device. We think the money saved by avoiding as few as 1 in 10 hospital transfers could pay for a VAD in all the service s ambulances within 7 months. Devices are easy to use, require very little training and could easily be taken up by services in other regions and countries to benefit more patients.

Research activity codes: 6.3 MEDICAL DEVICES
Health categories: CARDIOVASCULAR