Evaluation of Pre-hospital Use of a Valsalva Assist Devise (VAD) in the Emergency Treatment of Supraventricular Tachycardia (SVT). A Randomised Controlled Feasibility Trial [EVADE]
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 34
- 试验地点
- 1
- 主要终点
- Clinician recruitment
研究概览
简要总结
The Valsalva Assist Device (VAD) is a simple hand held device, designed to assist in the physical treatment of a common, fast heart rhythm disorder called supraventricular tachycardia (SVT).
This treatment, called the Valsalva manoeuvre (VM), is a safe, physical technique involving a forced exhalation against resistance (like that required to blow up a balloon). This causes a reflex slowing of the heart and can correct attacks of SVT (cardioversion). It is an internationally recommended initial treatment but previously has had a low success rate (5-27%) and patients often have to be taken to hospital for drug treatment.
Recent hospital research has demonstrated that a VM carried out using a certain level of strain pressure(40mmHg) measured with a blood pressure manometer, combined with a simple postural modification (the modified VM) gives a far better chance of success (43%) and avoids the need for drug treatment. More practical methods of generating this strain such as blowing on an empty syringe have been used but are unreliable. The Valsalva Assist Device (VAD) has been designed to provide the correct resistance and is packaged with instructions for the modified VM.
Attacks of SVT frequently occur without warning in otherwise healthy people. Patients are often initially seen by ambulance staff and so the use of the VAD therefore represents an opportunity to provide ambulance clinicians with instructions for the modified VM and a means to deliver the correct strain in one, easy to use device.
The investigators plan to test use of the device in patients with an attack of SVT and attended by paramedics or other pre-hospital practitioner, compared to current recommended practice. This project will provide important feasibility and recruitment data for a definitive trial, assessing the performance of the VAD on SVT cardioversion and conveyance (transfer to hospital) rates.
详细描述
The investigators plan to conduct a pragmatic, randomised controlled trial of the use of the Valsalva Assist Device (VAD) versus standard care to treat SVT delivered by ambulance clinicians.
Ambulance clinicians within South West Ambulance Service Foundation Trust (SWASFT) will be invited to help deliver this study by becoming recruiting practitioners. All participating ambulance clinicians will have specific trial training including an update of SVT management, use of the VAD and GCP training as needed. It is estimated a two month ambulance clinician recruitment period would enable approximately 80 clinicians to be enrolled.
Patients presenting with SVT to these trained participating ambulance clinicians will be screened according to the eligibility criteria during their initial clinical assessment over a 6-8 month concurrent recruitment period. This will include routine observations and recording of an ECG.
Eligible participants will be informed about the nature of SVT and the VM as the initial recommended treatment. They will then take part in a structured verbal consent process, witnessed by a second member of ambulance staff or nominated individual such as a relative or friend. They will be given a verbal explanation of the study and that the proposed treatment differs only in the method used to generate the Valsalva strain and that all other management is entirely as normal. It will be stressed that they are under no obligation to take part and that the method of producing the strain will be chosen at random on the opening of a box containing a simple device (VAD) or instructions advising usual practise such as blowing into a syringe.
These boxes will be indistinguishable and distributed to participating ambulance clinicians at random. Clinicians will carry one box at a time and restock by taking the next available lowest numbered box from their ambulance station when used. They will be closed with a tamper evident seal and not opened until the witness has confirmed the patient's verbal consent to take part and that the box's seal is intact.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Double (Investigator, Outcomes Assessor)
盲法说明
Data analysis and determination of primary outcome will be done blind to allocation
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Adult patients (above 17years)
- •Presenting with SVT which the ambulance clinician identifies as being eligible for a vagal manoeuvre
排除标准
- •Unable or unwilling to give informed verbal consent
- •Unstable condition (systolic blood pressure (BP) < 90mmHg) [Increased risk of feeling or actually fainting with a VM which causes a transient fall in BP as a normal physiological response]
- •Atrial fibrillation or atrial flutter on ECG [VM considered ineffective in these rhythms]
- •Severe hypertension (systolic BP >220mmHg or diastolic BP >120mmHg) [Risk of further increase in BP at end of VM - a normal physiological response]
- •Contraindication or inability to perform a modified Valsalva manoeuvre in the opinion of the practitioner. This will include but not limited to: Aortic stenosis, recent myocardial infarction, glaucoma, retinopathy and inability to perform a Valsalva manoeuvre, to lie flat or have legs lifted. [We will exclude all those that could conceivable come to any harm from performing a VM]
- •Third trimester pregnancy [Lying flat can cause fainting in late pregnancy]
- •Prisoners
- •Previous inclusion in the study
结局指标
主要结局
Clinician recruitment
时间窗: At study completion (after an 8 month recruitment period)
A key measures for this pilot project will be the rate of ambulance clinician recruitment.
Participant recruitment
时间窗: At study completion (after an 8 month recruitment period)
The number of participants recruited to the trial
次要结局
- Completeness of data(At study completion (after an 8 month recruitment period))
- Cardioversion rates(At study completion (after an 8 month recruitment period))
- Conveyance rates(At study completion (after an 8 month recruitment period))