The objective of this educational clinical trial is to compare auditory (metronome) and audiovisual (TrueCPR) feedback systems with both standard CPR and with each other in a simulated environment, focusing on their effects on chest compression quality.

The main research questions are:

• Does the use of a metronome improve CPR performance metrics compared to standard CPR?
• Does the use of TrueCPR improve CPR performance metrics compared to standard CPR?
• Is TrueCPR more effective than the metronome in improving CPR performance metrics?

Researchers will evaluate the impact of auditory (metronome) and audiovisual (TrueCPR) feedback systems on chest compression quality by comparing them to standard CPR and to each other within a simulated clinical educational environment.

Participants:

A total of 179 participants, consisting of medical students (n = 112) and paramedic students (n = 67), will be involved in the study.

All participants will attend a 30-minute orientation session. Participants who meet the inclusion criteria and agree to participate (medicine, n = 21; paramedic, n = 62) will sign an informed consent form prior to the study.

They will then complete a preliminary assessment, including a 5-question knowledge test on high-quality CPR metrics.

Perform 2 minutes of chest-compressions-only CPR (standard CPR) on a manikin without any feedback.

All participants will be pooled and randomized. They will receive a 10-minute general briefing session after randomization.

Study Groups:

Group1: Standard-to-Metronome Group (n = 43) will:

Perform 2 minutes of chest-compressions-only CPR (standard CPR) on a manikin without any feedback.

Not receive device-specific training or use a multisensory feedback device. Take a 5-minute rest period. Perform 2 minutes of CPR using metronome feedback.

Group 2: Standard-to-TrueCPR (n = 40) will:

Perform 2 minutes of chest-compressions-only CPR (standard CPR) on a manikin without any feedback.

Receive a 30-minute TrueCPR-specific training session and use a multisensory feedback device.

Take a 5-minute rest period. Perform 2 minutes of CPR using TrueCPR feedback.

A. Study Preparation Study Setting This study was conducted in the Professional Skills Laboratories of Başkent University Faculty of Medicine. Basic Life Support (BLS) simulations were organized as standardized, single-station sessions and performed on an advanced ACLS manikin situated in a spacious hands-on training room. While one participant performed chest compressions, others waited in a nearby area until it was their turn.

Research Personnel Two faculty members designed the simulation environment and BLS scenarios, supervised orientation training for both investigators and participants, and coordinated study sessions. Additionally, five medical student researchers assisted in setting up the simulation environment, managing participant flow, delivering orientation sessions, and obtaining informed consent.

Orientation Session A 30-minute orientation session was held on two separate days for the study population (medicine, n = 112; paramedic, n = 67), during which the study purpose, pre- and post-randomization procedures, study setting, and participant expectations were explained.

Preliminary Assessment Before the randomization phase, a preliminary assessment was conducted to evaluate the similarities in high-quality CPR knowledge and performance between medical and paramedic students.

• Participants who attended the orientation were invited to participate in the study (n = 83). Demographic data were collected, and informed consent was obtained from volunteers meeting the inclusion criteria (medicine, n = 21; paramedic, n = 62).
• A five-question knowledge test covering key high-quality CPR metrics was administered. The test scores were recorded for all eligible participants.
• Each participant then performed 2 minutes of chest-compressions-only CPR on an advanced ACLS manikin without feedback. Compression rate, depth, and residual leaning percent were recorded for each participant.
• Knowledge test and performance data were analyzed separately for medical and paramedic students.
• Analyses showed no significant differences in theoretical knowledge or practical performance between the two groups.
• Due to this equivalence, participants were pooled and randomized irrespective of their educational background.

Randomization

Two sets of labels were prepared: one labeled "standard to metronome" and "standard to TrueCPR," and the other labeled "Group 1" and "Group 2." These were matched by blind draw to assign the intervention types to each group:

Group 1: Metronome group, "Standard to Metronome" (no device-specific training or multisensory feedback) Group 2: TrueCPR group, "Standard to TrueCPR" (device-specific training and audiovisual feedback)

Of 179 eligible participants, 83 met the inclusion criteria, demonstrated equivalent knowledge and performance, gave informed consent, and were randomized. A block randomization method (1:1 ratio) was implemented using a web-based tool (Urbaniak GC, http://www.randomizer.org/) to ensure balanced allocation. Participants were assigned to either Group 1 (n = 43) or Group 2 (n = 40). The slight imbalance reflected differences in enrollment timing and participant availability and was acceptable within block design limits.

To maintain allocation concealment, the randomization sequence was generated and managed by an independent researcher not involved in recruitment or data collection. The allocation list was stored securely and remained inaccessible to investigators until the assignment.

Because standard CPR, metronome-assisted CPR, and TrueCPR-assisted CPR are clearly distinguishable in cognitive, visual, and auditory dimensions, the study was conducted as open-label for researchers, participants, and the data analyst.

B. Study Interventions Group assignments were performed by an independent researcher prior to the start of the trial to ensure unbiased allocation.

Group 1 (n = 43): Performed chest-compressions-only CPR (standard CPR) followed by metronome-assisted CPR, without receiving any specific training or multisensory feedback.

Group 2 (n = 40): Performed device-specific training (TrueCPR) and performed chest-compressions-only CPR (standard CPR) followed by TrueCPR-assisted CPR with auditory and visual feedback. In this group, one participant did not complete the CPR session with TrueCPR.The number of participants included in the analyses was 39 (n = 39).

Intervention Steps

1. At the beginning of the trial, both groups received a standardized 10-minute briefing, including an overview of the study protocol, orientation to the simulation lab, and introduction to the research team.

2. In a single-station setup:

   Group 1 participants first performed 2 minutes of standard CPR without ventilation or feedback. After a 5-minute rest, they performed another 2 minutes of CPR assisted by a metronome. The metronome feature was embedded in the advanced ACLS manikin and provided auditory feedback only. No additional training was given.

3. On a different day, using the same station:

   Group 2 participants first performed 2 minutes of standard CPR without feedback. Then, they received a 30-minute device-specific TrueCPR training, which included:

   A 10-minute instructional video, A 10-minute didactic session, A 5-minute demonstration and Q&A session, A 2-minute individual hands-on practice, A 5-minute rest period. Finally, they performed 2 minutes of CPR using the TrueCPR device, which provided real-time audiovisual feedback.

4. Chest compression rate (cpm), depth (mm), and leaning percent (%) were measured and recorded during standard CPR, metronome-guided CPR, and TrueCPR-assisted CPR using the Ambu SmartMan ALS Pro+ (AW301) manikin.

Inclusion Criteria:

• Being a first- or second-year student in the medical school or paramedic program
• Having completed a standardized Basic Life Support (BLS) course as part of the curriculum
• Having no prior experience with CPR feedback devices
• Voluntarily agreeing to participate and signing the informed consent form
• Being able to complete all required chest compression steps during the study procedure

Exclusion Criteria:

• Being a student other than first- or second-year in the medical school or paramedic program
• Not having completed a standardized Basic Life Support (BLS) course as part of the academic curriculum
• Having prior experience with CPR feedback devices
• Refusing to participate or failing to sign the informed consent form
• Being unable to perform all required chest compression steps during the study procedure

There is currently no plan to share individual participant data (IPD). As the data are the property of Başkent University, any decision regarding access must be made at the institutional level. During the publication process of the study, IPD may be shared upon request to the principal investigator and is subject to institutional approval.

Blinding was maintained during data analysis.