Effect of vehicle speed on the quality of closed-chest compression during ambulance transport

Transport of patients with ongoing cardiopulmonary resuscitation (CPR) occurs frequently. It may not be possible to obtain rapid hospital access while maintaining CPR quality, because the ambulance's high speed can cause increased vibration and vehicle movement. We aimed to assess how the speed of ambulance affects chest compressions.

Five cycles of CPR were performed to the Resusci Anne manikin with the PC skill reporting system by experienced emergency medical technicians in ambulance traveling at one of four different speeds: stationary, 30, 60, or 90km/h. Performance and acceleration data of chest compressions at different speeds were compared using repeated measures analysis of variance (ANOVA).

Fractions of chest compressions with adequate depth, duty cycles, average rates of chest compressions, and no flow fractions showed significant differences among different speeds (p=0.026, <0.001, <0.001, 0.005, respectively), while average depth of chest compressions did not. Accelerations of 2Hz component and ratios of 3-12Hz to 0-2Hz components showed significant differences among different speeds (p=0.001 for all). None of the outcome variables showed a significant difference between the two types of ambulance.

The speed of ambulance affects some aspects in the quality of chest compression during transport. Chest compressions with excessive depth, the average rate of chest compressions, and no-flow fraction increase as the speed of ambulance increase. Increase in the speed of ambulance also causes relative increase of high frequency acceleration in the chest compression, which represents unnecessary movement and force applied.