VANZ2
Research type
Research Study
Full title
The impact of introducing real time feedback on ventilation rate and volume by ambulance clinicians in out of hospital cardiac arrest: the VANZ2 study
IRAS ID
295868
Contact name
Karl Charlton
Contact email
Sponsor organisation
North East Ambulance Service NHS Foundation Trust
ISRCTN Number
ISRCTN54864230
Duration of Study in the UK
0 years, 5 months, 30 days
Research summary
Research Summary
Cardiac arrest is a life-threatening emergency and occurs when the heart suddenly stops beating. When the heart stops beating it cannot pump blood to the brain, lungs and other organs. When a cardiac arrest occurs in the community, outside of a hospital setting, it is called an out of hospital cardiac arrest (OHCA).
When a paramedic attends a person suffering OHCA, they are required to deliver chest compressions and to assist breathing, which involves inserting a tube into the patients’ mouth, and squeezing a bag inflated with oxygen to assist or take over the patients’ breathing.
When delivering oxygen, it is important to deliver the right amount. Although recommendations exist to tell paramedics how much oxygen to deliver, many paramedics deliver to much or to little as until recently there has been no method to measure how much each patient receives.
A new feedback device has been developed that attaches to the tube that is inserted into the patients’ mouth. The other end of the device connects to the defibrillator screen used by paramedics. When a paramedic squeezes the bag to deliver oxygen, the amount of oxygen delivered appears on the screen, so the paramedic can respond to any under or over delivery of oxygen. A five second counter tells the paramedic when to squeeze the bag at the right time.
The researchers propose a clinical trial to see if feedback can improve paramedic compliance with ventilation recommendations during OHCA and to see if this leads to improved patient outcomes.
Eligible for inclusion are all patients suffering OHCA, aged 18 years of age and above, who receive resuscitation by the ambulance crew.
Patients will be enrolled into the study without prior consent due to the emergency situation and because the patient will be unconscious. We will seek written informed consent for all survivors.Summary of Results
14 participants were enrolled into the study. Baseline ventilation quality (rate and volume) was frequently outside of recommendations in the absence of feedback but improved when feedback was provided (3% versus 25%). Without feedback the baseline ventilation rate was more frequently in excess of recommendations compared to with feedback (66% versus 41%). The mean ventilation rate (breaths per minute) with feedback was higher than without (17 versus 14) but the percentage rate within recommendations throughout the resuscitation was improved overall when feedback was provided compared to without (46% versus 18%). Mean tidal volume was outside of recommendations without feedback but within recommendations when feedback was provided (467 ml versus 563 ml). Feedback improved the percentage of ventilations delivered within the recommended volume throughout the resuscitation (46% versus 18%).
In addition, chest compressions were more compliant with recommendations when the ventilation feedback was provided. Compression rate was improved with, compared to without, ventilation feedback (79% versus 38%).
The connection between excessive ventilations and patient outcomes remains unclear and further research is needed to confirm any association.
REC name
Wales REC 1
REC reference
21/WA/0145
Date of REC Opinion
7 Jun 2021
REC opinion
Further Information Favourable Opinion