Comparison of chest compression kinematics associated with over-the-head and standard cardiopulmonary resuscitation

Abstract

Background

Over-the-head cardiopulmonary resuscitation (CPR) is a method of chest compression, which may be easier to perform than standard CPR in a confined space.

Purpose

The purpose of this study was to evaluate the effects of over-the-head CPR on the kinematics and the force of delivered compressions.

Methods

The subjects were 21 health care providers who were experienced in CPR. Each participant performed over-the-head CPR (O) and standard CPR (S). The compression-to-ventilation ratio was 30:2. The CPR duration was 2 minutes in each position, with a rest period of 15 minutes between each instance. The order in which positions were adopted was randomized. A manikin was equipped with a 6-axial force load cell to collect 3-dimensional compression forces at a sampling rate of 1000 Hz. An 8-camera digital motion analysis system was used to collect 3-dimensional trajectory information. Data were compared by crossover design analysis of variance (P < .05 represents statistical significance).

Results

No significant differences in range of motion of the head, shoulder, lower trunk, hip, and knee were obtained using the 2 methods. The compression forces in O and S were 386.64 ± 47.32 and 397.35 ± 41.89 N, respectively (P > .05). No significant differences between the compression frequencies, depths, and percentages correct were obtained using the 2 methods.

Conclusions

There were no differences between the kinematics, compression forces, depths, and frequencies obtained using the O and S CPR methods as practiced by experienced providers.

Introduction

Early cardiopulmonary resuscitation (CPR) is an important action in the chain of survival for cardiac arrest [1], [2], [3]. However, a normal cardiac output could not be obtained even when chest compression is correctively and optimally performed [4]. This condition is worsened when the CPR is implemented or performed in a confined space, for example, in the ambulance.

There has been little prior work on the effects of rescuers of performing CPR in a confined space. Recently, an alternative method called over-the-head CPR has been developed for such conditions [5]. Unlike in standard CPR, in which the rescuers must place a knee above and beside the head of the victim to perform ventilation and chest compression, in this approach, the CPR provider need not move their body during alternate chest compression and ventilation. Investigations have demonstrated that the efficiency of over-the-head CPR is as good as or even better than that of standard CPR [5], [6], [7], [8].

Most research on CPR techniques discusses the effects of motion (performance outcome), compression depth, compression rate, and cyclic time [9], [10]. However, the position of the rescuer may affect the muscle recruitment and therefore the performance of CPR [11]. The hypothesis of this study is that the effect that positioning might have on standard vs over-the-head CPR, that is, the position affects the kinematics (angle of motion) and kinetics (forces delivered, depth, and frequency) during CPR. This work thus explores the effect of motion on the performance of chest compression. The goal of this work was to compare over-the-head CPR with standard CPR to investigate the kinematics and kinetic factors of the over-the-head CPR on manikin model.