New approach to treating cardiac arrest with persistent shockable rhythms

Vector Change Defibrillation in Refractory Shockable Rhythms

Thames Valley Air Ambulance · NCT05926973

This study is testing a new way to help adults who have cardiac arrest with certain heart rhythms by using a special CPR device and new pad placements to see if it improves their chances of getting their heart beating again.

Quick facts

Study typeObservational
Enrollment50 (estimated)
Ages18 Years and up
SexAll
SponsorThames Valley Air Ambulance (other)
Locations1 site (Oxford, Oxfordshire)
Trial IDNCT05926973 on ClinicalTrials.gov

What this trial studies

This observational study evaluates an enhanced algorithm for managing adult patients experiencing cardiac arrest due to refractory shockable rhythms, specifically continuous ventricular fibrillation (VF) or ventricular tachycardia (VT) after five shocks. The intervention involves using a mechanical CPR device during defibrillation and applying new pads in a specific position to improve outcomes. The study analyzes data from the Thames Valley Air Ambulance's HEMSBASE database over an 18-month period following the implementation of this new treatment bundle. The primary outcome measure is the return of spontaneous circulation (ROSC) at the hospital, indicating the effectiveness of the pre-hospital resuscitation efforts.

Who should consider this trial

Good fit: Ideal candidates for this study are adult patients who suffer from medical cardiac arrest with refractory shockable rhythms.

Not a fit: Patients with traumatic cardiac arrests or those experiencing recurrent VF/VT may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could significantly improve survival rates and outcomes for patients experiencing refractory shockable rhythms during cardiac arrest.

How similar studies have performed: While this approach builds on established guidelines, it introduces novel elements that have not been extensively tested in prior studies.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* adult patients with medical cardiac arrest
* in refractory shockable rhythms (defined as continuous VF or VT after 5 shocks).

Exclusion Criteria:

* traumatic cardiac arrests
* cardiac arrests where the VF/VT was recurrent (could be terminated but then restarted) rather than refractory (unable to get the patient out of the shockable rhythm). Refractory VF refers to VF that persists despite shock delivery (i.e. shock-resistant VF). This is distinguished from recurrent VF, which is VF that re-appears after it has been terminated (2). In this study refractory would be defined as continuous VF or VT after 5 shocks.

Where this trial is running

Oxford, Oxfordshire

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Cardiac Arrest, Ventricular Fibrillation, Ventricular Tachycardia, cardiac arrest, Refractory shockable rhythm, defibrillation

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.