Abstract P73: Description of the Acceleration Forces Affecting Balance of Pre-hospital Providers While Delivering Cardio-Pulmonary Resuscitation
Introduction: EMS personnel are subjected to numerous large forces due to ambulance acceleration while caring for patients. These forces may increase the risk of crew injury due to balance loss and negatively affect patient care, especially if crew members are standing to perform CPR. Previous studies have demonstrated that acceleration exceeding 0.6 to 0.93 m/s^2 leads to loss of balance. Furthermore, acceleration per unit time (i.e. jerk) has been suggested as a stronger predictor of balance loss and should be limited to 0.5 to 0.6m/s^3. We sought to identify the frequency with which ambulance personnel are at risk of balance loss during the transport of cardiac arrest patients.
Methods: An onboard monitoring system (Road Safety, Thousand Oaks, CA) was utilized to record lateral and axial acceleration data during the transport of 50 cardiac arrest patients. Acceleration and acceleration change vectors were calculated for every second of drive time (speed >0 mph). Percentage of drive time with critical acceleration (>0.93 m/s^2) and jerk (>0.6 m/s^3) was determined by identifying all events exceeding the critical threshold.
Results: Total drive time during these transports was 348.03 min (mean 6.95 min per transport). Acceleration exceeded 0.93 m/s^2 49% of time (165.27 min, mean 3.31 min), and acceleration changes (jerk) exceeded 0.6 m/s^3 (86.87 min, mean 1.74 min) 26% of time. Either critical threshold was exceeded 60% of time ( 202.42 min, mean 4.05 min) during transport.
Conclusion: During cardiac arrest patient transports emergency medical personnel are at significant risk of balance loss 60% of the time due to frequent, large acceleration forces. The resulting loss of balance may result in personal injury or the delivery of poor quality CPR.