Measuring the Effect of Off-Balancing Vectors on the Delivery of High-Quality CPR during Ambulance Transport: A Proof of Concept Study.

AIM: This study aims to demonstrate the feasibility of quantifying the off-balancing vectors experienced during ambulance transport and comparing them to high-quality cardiopulmonary resuscitation (HQ-CPR) metrics. METHODS: Ten participants completed a total of 20 evolutions of compression-only HQ-CPR in an ambulance driven in a manner that minimized or increased linear and angular off-balancing vectors. Linear and angular velocity, linear and angular acceleration, and linear jerk were recorded. HQ-CPR variables measured were compression fraction and proportion of compressions with depth >5 cm (depth%), rate 100-120 (rate%), full chest recoil (recoil%), and hand position (hand%). A composite score was calculated: [(depth% + rate% + recoil% + hand%)/4) * compression fraction]. Difficulty of HQ-CPR performance was measured with the Borg rating of perceived exertion (RPE) Scale. A series of mixed effects models were fitted regressing each HQ-CPR metric on each off-balancing vector. RESULTS: HQ-CPR data and vector quantity data were successfully recorded in all evolutions. Rate% was negatively associated with increasing linear velocity (slope = -3.82, standard error [SE] 1.12, p = 0.005), linear acceleration (slope = -5.52, SE 1.93, p = 0.013), linear jerk (slope = -17.60, SE 5.78, p = 0.007), angular velocity (slope = -75.74, SE 22.72, p = 0.004), and angular acceleration (slope = -152.53, SE 59.60, p = 0.022). Compression fraction was negatively associated with increasing linear velocity (slope = -1.35, SE 0.37, p = 0.004), linear acceleration (slope = -1.67, SE 0.48, p = 0.003), linear jerk (slope = -4.90, SE 1.86, p = 0.018), angular velocity (slope = -25.66, SE 6.49, p = 0.001), and angular acceleration (slope = -45.35, SE 18.91, p = 0.031). Recoil% was negatively associated with increasing linear velocity (slope = -5.80, SE 2.21, p = 0.023) and angular velocity (slope = -116.96, SE 44.24, p = 0.019)). Composite score was negatively associated with increasing linear velocity (slope = -4.49, SE 1.45, p = 0.009) and angular velocity (slope = -86.13, SE 31.24, p = 0.014) and approached a negative association with increasing magnitudes of linear acceleration (slope -5.54, SE 2.93, p = 0.075), linear jerk (slope = -17.43, SE 8.80, p = 0.064), and angular acceleration (slope = -170.43, SE 80.73, p = 0.051). Borg RPE scale was positively associated with all off-balancing vectors. Depth%, hand%, mean compression depth, and mean compression rate were not correlated with any off-balancing vector. CONCLUSION: Off-balancing vector data can be successfully quantified during ambulance transport and compared with HQ-CPR performance parameters. Increasing off-balancing vectors experienced during ambulance transport are associated with worse HQ-CPR metrics and increased perceived physical exertion. These data may help guide future drive styles, ambulance design, or use of mechanical CPR devices to improve HQ-CPR delivery during selected patient transport scenarios.

Manual versus Mechanical Delivery of High-Quality Cardiopulmonary Resuscitation on a River-Based Fire Rescue Boat.

OBJECTIVES: Studies have demonstrated the efficacy of mechanical devices at delivering high-quality cardiopulmonary resuscitation (HQ-CPR) in various transport settings. Herein, this study investigates the efficacy of manual and mechanical HQ-CPR delivery on a fire rescue boat. METHODS: A total of 15 active firefighter-paramedics were recruited for a prospective manikin-based trial. Each paramedic performed two minutes manual compression-only CPR while navigating on a river-based fire rescue boat. The boat was piloted in either a stable linear manner or dynamic S-turn manner to simulate obstacle avoidance. For each session of manual HQ-CPR, a session of mechanical HQ-CPR was also performed with a LUCAS 3 (Stryker; Kalamazoo, Michigan USA). A total of 60 sessions were completed. Parameters recorded included compression fraction (CF) and the percentage of compressions with correct depth >5cm (D%), correct rate 100-120 (R%), full release (FR%), and correct hand position (HP%). A composite HQ-CPR score was calculated as follows: ((D% + R% + FR% + HP%)/4) * CF%). Differences in magnitude of change seen in stable versus dynamic navigation within study conditions were evaluated with a Z-score calculation. Difficulty of HQ-CPR delivery was assessed utilizing the Borg Rating of Perceived Exertion Scale. RESULTS: Participants were mostly male and had a median experience of 20 years. Manual HQ-CPR delivered during stable navigation out-performed manual HQ-CPR delivered during dynamic navigation for composite score and trended towards superiority for FR% and R%. There was no difference seen for any measured variable when comparing mechanical HQ-CPR delivered during stable navigation versus dynamic navigation. Mechanical HQ-CPR out-performed manual HQ-CPR during both stable and dynamic navigation in terms of composite score, FR%, and R%. Z-score calculation demonstrated that manual HQ-CPR delivery was significantly more affected by drive style than mechanical HQ-CPR delivery in terms of composite HQ-CPR score and trended towards significance for FR% and R%. Borg Rating of Perceived Exertion was higher for manual CPR delivered during dynamic sessions than for stable sessions. CONCLUSION: Mechanical HQ-CPR delivery is superior to manual HQ-CPR delivery during both stable and dynamic riverine navigation. Whereas manual HQ-CPR delivery was worse during dynamic transportation conditions compared to stable transport conditions, mechanical HQ-CPR delivery was unaffected by drive style. This suggests the utility of routine use of mechanical HQ-CPR devices in the riverine patient transport setting.