Development of a model to measure the effect of off-balancing vectors on the delivery of high-quality CPR in a moving vehicle

Aim: We sought to develop a model to measure the acceleration and jerk vectors affecting the performance of High-Quality Cardiopulmonary Resuscitation (HQ-CPR) during patient transport.

Methods: Three participants completed a total of eighteen rounds of compression only HQ-CPR in a moving vehicle. The vehicle was driven in a manner that either minimized or increased linear and angular vectors. The HQ-CPR variables measured were compression fraction (CF%), and percentages of compressions with correct depth > 5 cm (D%), rate 100-120 (R%), full recoil (FR%), and hand position (HP%). A composite HQ-CPR score was calculated: ((D% + R% + FR% + HP%)/4) * CF%). Linear and gyroscopic data were measured in the X, Y, and Z axes. The perceived difficulty in performing HQ-CPR was measured with the Borg Rating of Perceived Exertion Scale.

Results: HQ-CPR data, linear vector data, and gyroscopic data were successfully recorded in all trial evolutions. Univariate regression analysis demonstrated that HQ-CPR was negatively affected by increasing magnitudes of linear acceleration (B = -0.093%/m/s², 95% CI [-0.17 - -0.02), p = 0.02], linear jerk (B = -0.134%/m/s³, 95% CI [-0.26 - -0.01], p = 0.04), angular velocity (B = -0.543%/radian/s, 95% CI [-0.98 - -0.11], p = 0.02), and angular acceleration (B = 0.863%/radian/s², 95% CI [-1.69 - -0.03], p = 0.04). Increasing vectors were negatively associated with FR% and R%. No difference was seen in D%, HP%, or CF%. Borg Rating of Perceived Exertion was greater in dynamic driving evolutions (8 ± 1 vs 3.5 ± 1.53, p = 0.02).

Conclusion: This model reliably measured linear and angular off-balancing vectors experienced during the delivery of HQ-CPR in a moving vehicle. In this preliminary report, compression rate and full recoil appear to be HQ-CPR variables most affected in a moving vehicle.