This study was performed experimentally by the EMS of Ankara City (the capital of Turkey). Ethics committee approval of the study from University of Health Science, Turkey.
a. Characteristics of the Participants
Twenty paramedics—each of which had at least five years of field experience in the EMS of Ankara City and had completed the four training modules of the Ministry of Health (MoH) of the Republic of Turkey—were included in this study on a voluntary basis. The paramedic participants were allowed to get used to the training model by practicing on it for 10 minutes before the study. Participants were asked to apply chest compressions to the training model (in accordance with the 2015 AHA guidelines) within the moving ambulance. All safety measures were taken to prevent the paramedic participants from skidding, falling, or being injured while administering chest compressions (Fig. 1).
b. Characteristics of the Ambulance Driving Track
The points where paramedics would have difficulty to perform CPR in the ambulance had been pre-evaluated. To prevent these difficulties in advance, a driving track for ambulance driving training was simulated in accordance with the national standards of the MoH of Turkey and the actual conditions. The driving track is designed to help drivers practice evasive maneuvering, parking, slalom, swiveling, and panic braking. The width of the driving track was 1.5 meters, and its total length was 269 meters (Fig. 2).
The study was originally intended to be carried out on a city traffic route instead of a simulated driving track. However, since the volume of traffic could not be standardized, it was finally decided to carry out the study on this driving track.
c. Characteristics of the Ambulance
In this study, a fully equipped training ambulance (Mercedes Sprinter®, 2015, Germany) from the EMS of Ankara City was used. To ensure standardization, the ambulance was driven by the same ambulance driving trainer each time. Before the start, the driver was allowed to take five practice laps to get used to the driving track. During the study, the drivers were asked to go as fast as they could, but they reached a maximum speed of 20 km per hour to ensure ambulance paramedics safety. The speed was up to 40 km / h on the straight-ahead route, while the maximum speed was 20 km / h in the maneuvering areas.
d. Characteristics of the CPR Training Model
The Simman 3 training model (Laerdal®, Stavanger, Norway 2014) was used to measure the speed of the chest compressions and the duration of the interruptions between them, which are indicators of CPR quality. While the ambulance was driven on the track, the paramedic or the MCCD performed chest compressions on the model. The MCCD was fixed to the model by using belts to prevent it from sliding over the model. The model was fixed to the ambulance stretcher by a three-point climbing belt to prevent the model from sliding. Chest compressions were started immediately when the ambulance began to move. The training model recorded the chest compression rate (number of compressions per minute), compression depth, and hands-off time*.
* Hands-off time” describes the interruptions that occur during chest compression.
The LUCAS Chest Compression System (Physio-Control/ Jolife AB) was used as MCCD. MCDD was fixed to the manikin by fastening the belts. The chest compression rate of the MCCD was set to 100 / min, while its compression depth was set to 5 cm.
In the first stage, the paramedic participants performed manual chest compressions on the model while the ambulance was moving. To assess the effectiveness of the paramedics, each of the 20 paramedics took 2 laps around the track (20 paramedics × 2 laps = 40 laps). Since the ambulance did not move straight, and maneuvered continuously, it was thought that one round would not be enough to assess the effectiveness of each paramedic. Therefore, each paramedic was asked to perform chest compression for 2 rounds. One lap of the ambulance around the track took an average of two minutes (totally 80 minutes).
In the second stage, in order to ensure the equal time and CPR conditions with paramedics, 40 more laps were driven performing chest compressions with the MCCD. To make comparisons with paramedics, at the end of each 2 laps, the number of chest compressions, the depth of compressions, and hands-off time were recorded; the CPR process and ambulance movements were recorded by cameras placed in the front and rear cabin of the ambulance.
f. Statistical analysis
All data recorded during the study were analyzed using SPSS software version 15.0 (for Windows, Chicago, IL, USA). Categorical data were expressed as frequencies and percentages. The Kolmogorov-Smirnow test was used to determine whether the continuous data had normal distribution. Whereas the variables that were normally distributed were expressed as means and standard deviations, the variables that were not normally distributed were expressed as medians and 25–75 quarter. Student's t-test was used for parametric data, whereas the Mann–Whitney U test was used for non-parametric data. To determine the statistical significance level, the critical alpha value was defined as p < 0.05.