Condition category
Circulatory System
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Background and study aims
High quality chest compressions are vital for survival after a cardiac arrest. Therefore bystanders are encouraged to act decisively in presence of a cardiac arrest victim. Telephone instructions are given by the emergency services responding to emergency calls. Unfortunately the quality of chest compression is usually inefficient because bystanders are often not trained. The aim of this study is to improve the quality of chest compression by comparing different instruction techniques.

Who can participate?
Your participation is voluntary. You need at least 18, give an informed consent and your blood pressure should be less than 150 mm Hg before the study starts.

What does the study involve?
Participants are randomly allocated to one of three groups: standard instructions given by emergency services over the phone, metronome over the phone, voice metronome over the phone.
If you take part two questionnaires are requested. The first one is about demographic data (age, smoking habits etc). The second questionnaire evaluates your physical fitness. Afterwards, you are requested to perform a skill test evaluating fine motor skills (you need to put pegs into holes with your non-dominant hand). Before the study starts your blood pressure and your heart rate are measured.
The main study is a simulated 10-minute cardiopulmonary resuscitation on a manikin (as for a cardiac arrest victim at home). Over the telephone, emergency services will give you instructions on how to resuscitate the victim (chest compression only resuscitation). During the resuscitation we will ask you for your subjective perceived exertion. After you have finished the simulated resuscitation scenario we will measure your heart rate and your blood pressure again. Also, you are requested to repeat the skill test.

What are the possible benefits and risks of participating?
There are no anticipated risks. The benefit will be improved basic life support skills.

Where is this study run from?
This study is organised by the Department of Emergency Medicine of the Medical University of Vienna. The study venue is a large shopping hall. Verbal instructions are given by a member of emergency services located in an emergency dispatch centre.

When is the study starting and how long is it expected to run for?
June 2014. Your participation will take only 15 minutes.

Who is funding the study?
The study is being funded by Laerdal Austria which will provide the Laerdal manikin.

Who is the main contact?
Dr. Raphael van Tulder

Trial website

Contact information



Primary contact

Dr Raphael van Tulder


Contact details

Department of Emergency Medicine
Medical University of Vienna
Waehringerguertel 18-20
+43 (0) 1 40400 1964

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Effect of a (voice) metronome on chest compression depth and compression rate in telephone-assisted cardiopulmonary resuscitation: a randomized three-armed simulation study



Study hypothesis

Compression depth can be improved by a continuously repeated voice metronome sequence: 'deep-deep-deep-deeper'.

Ethics approval

Medical University of Vienna Ethics Committee, 21/05/2013, 1318/2013

Study design

Prospective randomized investigator-blinded parallel-group simulation trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Cardiopulmonary resuscitation


The scenario is planned as an out of hospital, telephone assisted, bystander CPR. Substantial information about circumstances (at home, compression only, telephone assisted bystander CPR) is given prior to participation. Outcome is blinded to the participants. After informed consent, participants are guided to a simulation room where the manikin is prepared. Only minimal study staff will have access to the scenario room to avoid distractions. The study staff's assignment is documentation of parameters and not to be involved in bystander CPR. Participants will be staffed with a telephone to call the Emergency Dispatch Centre (EDC). In the EDC, a professional emergency dispatcher will be providing verbal prompts via telephone to the bystander.

Every participant will perform closed-chest compression for 10 minutes on a slightly modified Resusci Anne® Manikin (Laerdal, Norway) without giving rescue breaths. Participants will be randomized to one of three groups:

1. Standard instructions will be given by the emergency medical dispatcher via telephone following the AMPDS protocol V12.0 provided by the IAED.
2. A metronome with a rate of 110 bpm will be transmitted via telephone.
3. A voice metronome will continuously prompt: 'deep-deep-deep-deeper!' at a rate of 100 beats per minute.

Data will be collected using the Laerdal® PC Skill-Reporting System - a software used with the adult size Laerdal® Resusci® Anne SkillReporterTM manikin to collect the subjects' CPR performance.

Intervention type



Not Applicable

Drug names

Primary outcome measure

Chest compression depth, measured continously via the pc skillmeter software of the Resusci® Anne skillmeter

Secondary outcome measures

1. Quality of ECC defined as number of percent of adequately achieved compression depth, continously assesed via skillmeter pc
2. Time to measurable decay in chest compression depth, continously assesed via skillmeter pc
3. Frequency of chest compression, continously assesed via skillmeter pc
4. Correct recoiling of the manikin's chest, continously assesed via skillmeter pc
5. Heart rate/systolic blood pressure ratio reflecting physical strain, measured before and immediately after chest compression
6. BORG rate of perceived exertion measured at 2nd, 4th, 6th and 10th minute of chest compressions
7. Systolic and diastolic blood pressure, measured before and immediately after chest compression
8. Nine Hole Peg Test, measured before and immediately after chest compression

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Voluntary participants
2. Informed consent
3. Age over 18 years
4. Blood pressure less than 160 mmHg (systolic) before starting CPR simulation

Participant type


Age group




Target number of participants


Total final enrolment


Participant exclusion criteria

1. Healthcare professionals
2. Basic Life Support course performed within the last 6 months
3. Pregnancy
4. Blood pressure over 150 mm Hg (systolic) before starting CPR simulation

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Department of Emergency Medicine

Sponsor information


Medical University of Vienna (Austria)

Sponsor details

c/o Associate Prof. Dr. Harald Herkner
Clinical epidemiologist
Department of Emergency Medicine
Waehringerguertel 18-20/6D

Sponsor type




Funder type


Funder name

Laerdal (Austria)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

1. 2015 results in (added 21/01/2019)

Publication citations

Additional files

Editorial Notes

14/08/2019: The final enrolment number has been added from the reference. 21/01/2019: Publication reference added