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Background:

International consensus guidelines now support the use of “chest compressions-only” cardiopulmonary resuscitation (CPR) instructions (CCOIs) by emergency medical dispatch (EMD) personnel providing telephone assistance to untrained bystanders at a cardiac arrest scene. These guidelines are based largely on evolving experimental data and a clinical trial conducted in one venue with distinct emergency medical services (EMS) system features. Accordingly, the Council of Standards for the tyle='font-style: italic'>National Academies of Emergency Dispatch was asked to adapt a modified telephone CPR protocol, and specifically one that could be applied more broadly to the spectrum of EMS systems.

Methods:

A group of international EMD specialists, researchers and professional association representatives analyzed available scientific data and considered variations in EMS systems, particularly those in Europe and North America.

Results and conclusions:

Several recommendations were established: (1) to avoid confusion, bystanders already providing CPR should continue those previously learned methods; (2) following a sudden collapse unlikely to be of respiratory etiology, CCOIs should be provided when the bystander is not CPR-trained, declining to perform mouth-to-mouth ventilation or unsure of actions to take; (3) following 4 min of CCOIs, ventilations can be provided, but, for now, only at a compression–ventilation ratio of 100:2 until EMS arrives; (4) until more data become available, dispatchers should follow existing compression–ventilation protocols for children and adult cases involving probable respiratory/trauma etiologies; (5) EMD CPR protocols should account for EMS system features and receive quality oversight and expert medical direction.

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Summary

Background

Depending on the clinical setting, rescuers may provide CPR from a kneeling (if the patient is on the ground) or standing (if the patient is in a bed) position. The rescuer position may affect workload, and hence rate of fatigue and quality of CPR.

Purpose

This study evaluates how three common rescuer positions affect the kinematics of CPR and the force of delivered compressions.

Methods

Subjects were 18 health care providers experienced in CPR. Each participant performed CPR from three different positions: kneeling beside the Resusci^® Anne manikin placed on the floor (F); standing beside the manikin placed on a Table 63 cm in height (H), and standing beside the manikin placed on a Table 37 cm in height (L). The compression to ventilation ratio was 15:2. CPR duration was 5 min for each position, with a rest period of 50 min in-between. The order of position was randomised. The manikin was equipped with a six-axial force load cell to collect 3D compression forces at a sampling rate of 1000 Hz. An eight-camera Motion Analysis Digital System was adopted to collect 3D trajectory information. Data were compared using crossover-design analysis of variance (tyle='font-style: italic'>p < 0.05 was regarded as statistically significant). Ratings of Perceived Exertion (RPE) were measured by modified Borg scale.

Results

Significant differences were observed in the head, shoulder, lower trunk, hip and knee angles between the three methods. Lower trunk flexion angle (°) for H, L, and F were −14.52 ± 1.13, −28.83 ± 1.75, and 14.39 ± 1.14, respectively. Hip flexion angle for H, L, and F were −16.21 ± 3.30, −42.59 ± 4.75, and −47.39 ± 4.36, respectively. However, compression force (N) in H, L, and F were 455.8 ± 17.6, 455.7 ± 14.0, 461.5 ± 13.5, respectively (tyle='font-style: italic'>p > 0.05). Compression depths (mm) were: 43.5 ± 3.4, 42.0 ± 5.4, 44 ± 5.2, respectively (tyle='font-style: italic'>p > 0.05). Compression frequencies (times/min) were: 117.9 ± 12.4, 116.6 ± 13.4, 108.8 ± 11.7, respectively (tyle='font-style: italic'>p > 0.05). No differences were found between the three positions for RPE.

Conclusions

In this study, while the kinematics of CPR differed significantly with varying rescuer position, these differences did not affect the compression force, depth and frequency as performed by experienced providers.