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Abstract
Background The 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.
Methods We 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.
Results 75 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.
Conclusions Modified 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 number NCT03298880.
- acute care
- cardiac care
- arrhythmia
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Footnotes
Contributors IF recruited the participants, ran the study and wrote the first draft of the manuscript. PE advised on study design, conduced the statistical analysis and reviewed the manuscript drafts. IL co-supervised IF, advised on the project and reviewed the manuscript. AA conceived the idea for the study, co-supervised IF, reviewed and revised the manuscript and acts as guarantor. The project was part of IF’s Masters by Research (MbyRes) project at the University of Exeter and was also submitted to the RCEM undergraduate research competition.
Funding The project was supported by the University of Exeter Medical school as part of a Masters by Research project (IF) and the Academic Department of Emergency Medicine. IL’s contribution to this research was supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula. Valsalva Assist Devices were supplied by Meditech Systems and purchased jointly by the Academic Department of Emergency Medicine and the Academic Health Science Network (SW).
Disclaimer This paper presents independent research funded by the Academic Department of Emergency Medicine, Royal Devon & Exeter Hospital NHS Foundation Trust supported by the National Institute for Health Research (NIHR) Exeter Clinical Research Facility. The views expressed are those of the authors and not necessarily those of the Royal Devon & Exeter Hospital NHS Foundation Trust, the NIHR or the Department of Health.
Competing interests None declared.
Patient consent Not required.
Ethics approval This study was approved by the University of Exeter Medical School (The Research, Innovation, Learning and Development Building, Royal Devon and Exeter Hospital, Barrack Road, Exeter, UK) research committee.
Provenance and peer review Not commissioned; externally peer reviewed.