What muscles need to be trained for high-quality chest compression?

Effect of Ambulance Stretcher Bed Height Adjustment on CPR Quality and Rescuer Fatigue in a Laboratory Environment

Background: The quality of cardiopulmonary resuscitation (CPR) is closely related to the survival rate of a patient, and it is crucial to maintain the quality of CPR during the ambulance journey to the receiving hospital. The purpose of this study was to investigate the effects of different stretcher bed heights on operator CPR quality. Methods: In this randomized crossover trial, 16 male emergency medical technicians-paramedics (EMT-Ps) performed continuous chest compressions on a hemimorphic mannequin for 5 minutes, alternating between the current height of the stretcher bed on the ambulance (38 ± 1 cm) (S-38) and the height of the participant's midpoint of the patella (S-knee), where the stretcher bed surface is. Results: According to the analysis of the quality of CPR exercises with two different stretcher bed heights at 5 minutes of continuous chest compression, the mean chest compression depth (CCD) of the S-38 position (53.81 ± 1.91 cm) was significantly lower than that of the S-knee (55.12 ± 2.03 cm; p < 0.001). The mean chest compression rate (CCR) of the S-38 position (111.44 ± 3.44 beats/min) was significantly higher than that of the S-knee (109.63 ± 4.46 beats/min; p = 0.027). The mean of total chest compressions (TCC) of the S-38 position (557.44 ± 16.81 times) was significantly higher than that of the S-knee (548.24 ± 19.40 times; p = 0.029). The rating of perceived exertion (RPE) of the S-38 position was significantly higher than that of the S-knee (12.75 ± 1.91 %; p = 0.015). Only the chest compression rebound rate (CCRR) (S-38: 97.56 ± 4.63 % vs. S-knee: 98.31 ± 1.89 %, p = 0.401) and the chest compression fraction (CCF) (S-38: 98.44 ± 0.81 % vs. S-knee: 98.44 ± 0.96 %, p = 1.000) did not reach a significant difference. Conclusion: When a resuscitator is performing chest compressions in a standing position in an ambulance, the excessive downward leaning of the resuscitator's upper body affects CPR quality and increases fatigue. This study has verified that setting the stretcher bed of the ambulance at the knee height of the EMTs provides better CPR quality and lower fatigue.