The Impact Of Environmental Disturbances During Transport In Remote Areas On The Quality Of Cardiopulmonary Resuscitation (LUCAS Vs. Manual): A Combined Analysis Of Electrocardiography (ECG), Blood Pressure (BP), And Environmental Exposure Indices

Abstract

Maintaining high-quality, uninterrupted cardiopulmonary resuscitation (CPR) during patient transport is paramount for improving survival outcomes in out-of-hospital cardiac arrest (OHCA). This challenge becomes exponentially greater in remote, austere, or challenging environments, where the very act of transport introduces significant environmental disturbances. These disturbances – including intense vibrations from rough terrain or aircraft, unpredictable acceleration/deceleration forces, extreme temperature variations (both heat and cold), reduced oxygen availability at altitude, and severe spatial constraints within vehicles, aircraft cabins, or during extrication – create a hostile environment for effective resuscitation. Manual CPR, reliant on human providers, is highly susceptible to degradation under these conditions. Vibrations and motion make it difficult for rescuers to maintain consistent compression depth and rate, ensure full chest recoil, or minimize pauses. Physical exhaustion is accelerated by environmental stressors like heat or altitude hypoxia. Spatial constraints often prevent optimal rescuer positioning or even adequate access to the patient's chest. Consequently, the quality of compressions, a critical determinant of coronary and cerebral perfusion, frequently declines during transport, jeopardizing the patient's chance of survival. Mechanical CPR devices, such as the LUCAS system, are specifically engineered to deliver consistent, guideline-compliant chest compressions. They are posited as a key solution to mitigate the detrimental effects of transport-related environmental factors. By providing automated, piston-driven compressions, these devices maintain correct depth and rate despite vibration and motion, ensure consistent recoil, and significantly reduce hands-off time. Their design often allows deployment in confined spaces where manual CPR is impractical. Therefore, compared to manual CPR, mechanical CPR offers the potential to sustain high-quality, uninterrupted chest compressions throughout the physically demanding and disruptive transport phase in remote settings, thereby optimizing perfusion and improving the likelihood of neurologically intact survival.

Objective: To comprehensively evaluate the impact of simulated environmental disturbances encountered during remote area transport on CPR quality metrics, specifically comparing the LUCAS mechanical CPR device to manual CPR, utilizing synchronized physiological monitoring (ECG, BP) and quantitative environmental exposure indices.

Methods: A controlled, simulated transport study was conducted using a high-fidelity manikin placed on a motion platform replicating ambulance vibration profiles (ISO 2631-1) and acceleration forces. Environmental chambers simulated temperature extremes (-10°C to 40°C) and reduced oxygen (simulating ~2500m altitude). Spatial constraints were modeled. Experienced paramedic teams performed CPR (2-minute cycles) under baseline (static lab) and various disturbance conditions (vibration only, vibration+acceleration, temperature extremes, altitude, space constraints, combined). CPR quality metrics (compression depth, rate, recoil, hands-off time), physiological signals (ECG rhythm stability, simulated arterial blood pressure (BP) waveform characteristics - systolic, diastolic, mean arterial pressure (MAP)), and environmental indices (vibration dose value (VDV), peak acceleration (G), temperature (°C), oxygen partial pressure (mmHg), spatial index) were recorded synchronously. Data was analyzed using mixed-effects models, correlation analysis, and ANOVA.

Results: Environmental disturbances significantly degraded manual CPR quality across all metrics compared to baseline (p<0.001). Depth consistency decreased by 15-30%, rate variability increased by 20-40%, incomplete recoil increased by 25-50%, and hands-off time increased by 10-20% under disturbances. LUCAS performance remained consistent within manufacturer specifications (<5% variation) across all disturbance conditions (p>0.05 for within-LUCAS comparisons). Manual CPR resulted in significantly greater instability in simulated BP waveforms (fluctuations in SBP, DBP, MAP > 20 mmHg) and increased ECG artifact/noise compared to LUCAS (p<0.01). Strong negative correlations (r = -0.65 to -0.85) were observed between environmental indices (especially VDV, peak G, spatial index) and manual CPR quality metrics. LUCAS quality metrics showed negligible correlation (|r| < 0.2) with environmental indices. Combined disturbances had a synergistic negative effect on manual CPR quality and physiological signal stability. Subjective feedback highlighted the extreme physical difficulty and cognitive load of maintaining manual CPR under disturbances.

Conclusion: Environmental disturbances inherent to remote area transport significantly and substantially degrade the quality of manual CPR, leading to inconsistent hemodynamic support (as reflected in unstable BP waveforms) and increased ECG artifact. The LUCAS mechanical CPR device demonstrated remarkable resilience, maintaining consistent, guideline-compliant CPR quality and superior physiological signal stability across all tested environmental conditions. Quantitative environmental exposure indices provide valuable objective metrics for predicting CPR degradation. These findings strongly support the use of mechanical CPR devices like LUCAS for OHCA resuscitation during transport in remote and challenging environments to ensure uninterrupted, high-quality chest compressions, thereby optimizing the potential for neurologically intact survival.