Testing of a novel Valsalva Assist Device with supine and modified positions in healthy volunteers

Abstract

BackgroundThe Valsalva manoeuvre (VM) is used to treat supraventricular tachycardia (SVT) by inducing a vagal response (drop in HR). There is debate as to the best position in which to carry out the VM and how the strain should be delivered in practice. We aimed to compare vagal responses induced with supine and modified VMs using strains delivered with a standardised manometer or novel Valsalva Assist Device (VAD), a simple device to provide resistance to exhalation.MethodsWe conducted a repeated measures randomised trial of four VMs (two supine VM and two modified VMs), in healthy adult volunteers, with strains delivered using an adapted sphygmomanometer (manometer) or a VAD. Changes in HR, pressure and duration of strain and adverse events were monitored and compared between the techniques and devices. The trial was approved by the University of Exeter Medical School Research ethics committee.Results75 healthy participants aged 19–55 years were recruited over a 4-month period. A mixed-effects linear regression showed the modified VM resulted in a 3.8 beats per min (bpm) greater drop in HR compared with the supine VM (p=0.002, 95% CI 2.2 to 5.4). VM strains produced by the VAD were of a similar pressure but of slightly shorter duration and resulted in a 1.9 bpm smaller drop in HR compared with the manometer (p=0.01, 95% CI 0.4 to 3.4). There were no differences in adverse events.ConclusionsModified VM was associated with a greater drop in HR than a supine VM with no increase in adverse events in healthy volunteers. The VAD can be used to safely generate the recommended VM strain pressure, but produced a smaller drop in HR compared with a manometer and requires modification to enable the recommended strain duration to be achieved consistently.Trial registration numberNCT03298880.

Evaluation of the prehospital use of a Valsalva assist device in the emergency treatment of supraventricular tachycardia (EVADE SVT): study protocol for a stepped wedge cluster randomised controlled trial

“…A simple, easy to use Valsalva Assist Device (VAD) has been developed which provides the correct, recommended resistance (40 mm Hg) for the VM exhalation strain. 13 A Conformité Européene (CE) marked VAD has been produced by Meditech Systems Limited (www.meditechsystems.co.uk), marketed as the 'Valsa-Valve' VAD (see figure 1). This VAD includes instructions for use on the device and it's packaging, including information on the timings and the postural changes required for the mVM.…”

Evaluation of pre-hospital use of a valsalva assist device in the emergency treatment of supraventricular tachycardia [EVADE]: a randomised controlled feasibility trial

“…A local patient and public group (Exeter 10,000) have previously given an opinion on the concept and rational for the VAD and were supportive of future trials into its use [17]. Patients and patient advocates were further involved in the design and conduct of this project, particularly in respect of the consent process and in the trial management group.…”

“…A valsalva assist device (VAD) [Meditech Systems Ltd] has recently been developed. It has been designed to provide the recommended resistance to exhalation at a pressure of 40 mmHg, is small and portable and can be conveniently packaged with clear instructions on how to correctly perform the modified VM [17]. If successful, this single patient use device could then be left with the patient, should an attack recur.…”