Central nervous system perfusion is important for better neurological results in patients with return of spontaneous circulation. The desired perfusion can be achieved with quality chest compressions during CPR
13-17. The features of chest compressions are highlighted in detail in each new resuscitation guide
18. In the literature, there are studies comparing MCCD with manual compression. In the present study, MCCD is found more effective than manual compression in situations where physical conditions such as transportation are more difficult, and the workforce is limited. Gyory and et al.
19 put, “the machine does not get tired like a human and the quality of chest compressions does not decrease over time”.
Although paramedics performed chest compressions for only 2 minutes, ineffective chest compressions were measured at both chest stiffness levels. We think that the reason for this is the difficulty of the physical conditions (linear-angular acceleration, vibration, shake etc.) caused by the constant movement of the ambulance 20-23. The effort made by paramedics to keep their balance in the moving ambulance negatively affects their CPR performance24. Paramedics described doing compression in a moving ambulance as “potentially unsafe” 25. Studies have shown that the conditions such as acceleration, vibration, and shaking caused by the ambulance movement trigger reflexive movements of paramedics. These reflexive movements pose a danger to the paramedics and the patients. The use of MCCD will mitigate this danger 20,26-29.
The patient's body mass index or thorax flexibility affects the power to be applied for effective chest compression. In the literature, there are not enough studies examining the quality of chest compressions according to the physical characteristics of the patient, such as body mass and age. Although its importance is emphasised in guidelines, we think that chest compression cannot be applied effectively (100-120/min and 50-60 mm) to patients during transport in real life. In the present study, we measured effective number and depth chest compressions in the MCCD group at both chest wall stiffness levels. There was a significant difference in median values of compression depth between the paramedic and MCCD groups for the 6 N/mm chest wall stiffness. However, in this stiffness level, ineffective number of compression and ineffective depth of compression were measured the paramedic group. In 11 N/mm chest wall stiffness, the ineffective compression difference between the groups increased significantly.
In summary, CPR quality decreases during the patient's transport 21. In such cases, it can be said that MCCD usage becomes crucial. Because when MCCD is used during transportation, the quality of the compressions can be achieved as suggested in the guidelines 13.
The strengths of our study are the experienced paramedics and the ambulance moving in real city traffic.
In limitations, the clinical effect of the compressions that we interpret as an ineffective compression (<100/min, <5mm) was not be examined since we used a manikin. The effect of fatigue on CPR was not evaluated since the paramedics performed chest compression for only 2 minutes. A manikin was used in the study, and this manikin had two chest stiffness levels. Therefore, chest compression was not evaluated in patients with different physical features (infant, child, morbid obesity, etc.). In the study, assembly time of the MCCD to the patient was not evaluated. Assembly time that affects the onset of CPR may prolong in patients with high body mass index.
As a result, MCCD provides more effective chest compression during transport when compared to manual compression. The effectiveness of MCCD increases in patients with high body mass index.