Elsevier

Resuscitation

Volume 103, June 2016, Pages 37-40
Resuscitation

Simulation and education
A randomized control hands-on defibrillation study—Barrier use evaluation

https://doi.org/10.1016/j.resuscitation.2016.03.019Get rights and content

Abstract

Introduction

Chest compressions and defibrillation are the only therapies proven to increase survival in cardiac arrest. Historically, rescuers must remove hands to shock, thereby interrupting chest compressions. This hands-off time results in a zero blood flow state. Pauses have been associated with poorer neurological recovery.

Methods

This was a blinded randomized control cadaver study evaluating the detection of defibrillation during manual chest compressions. An active defibrillator was connected to the cadaver in the sternum-apex configuration. The sham defibrillator was not connected to the cadaver. Subjects performed chest compressions using 6 barrier types: barehand, single and double layer nitrile gloves, firefighter gloves, neoprene pad, and a manual chest compression/decompression device. Randomized defibrillations (10 per barrier type) were delivered at 30 joules (J) for bare hand and 360 J for all other barriers. After each shock, the subject indicated degree of sensation on a VAS scale.

Results

Ten subjects participated. All subjects detected 30j shocks during barehand compressions, with only 1 undetected real shock. All barriers combined totaled 500 shocks delivered. Five (1%) active shocks were detected, 1(0.2%) single layer of Nitrile, 3(0.6%) with double layer nitrile, and 1(0.2%) with the neoprene barrier. One sham shock was reported with the single layer nitrile glove. No shocks were detected with fire gloves or compression decompression device. All shocks detected barely perceptible (0.25(±0.05) cm on 10 cm VAS scale).

Conclusions

Nitrile gloves and neoprene pad prevent (99%) responder's detection of defibrillation of a cadaver. Fire gloves and compression decompression device prevented detection.

Introduction

CLEAR, Clear, Clear – has been the pre-shock dogma taught by resuscitation educators for decades.1 Defibrillation is the standard of care for the management of ventricular fibrillation and ventricular tachycardia2 (VF/VT), and involves the discharge of direct current through the chest.3 Unfortunately, being “clear” requires all rescuers to remove their hands from the chest, resulting in the immediate cessation of blood flow, i.e. pre-shock pause. In 2011, the Resuscitation Outcomes Consortium (ROC) reported that pre-shock and peri-shock pauses were independently associated with a decrease in survival to hospital discharge.4, 5 As such, minimizing interruptions on chest compressions has now become the primary goal of cardiac resuscitation.5

This places defibrillation, and continuous chest compression standards in direct conflict. The risk of electrocution for any rescuer touching the patient during the electrical discharge of defibrillation is the underlying source of the conflict – rescuer safety.6

The purported electrical shock hazard of defibrillation was due to the large, rigid, metallic electrodes which allowed for substantial variability with respect to electrode contact and the performance of the conductive gel.7 Current state-of-the-art electrode technology is vastly improved with self-adhesive pre-gelled and conforming electrode pads resulting in enhanced electrode-skin coupling.8 In addition, monitor technology has incorporated real-time impedance monitoring reducing required peak voltage.

This paper reports on the concept of delivering a defibrillatory shock without removing the rescuer's hands in an experimental cadaver model, and the assessment of various potential rescuer safety barriers.

Hypothesis

Defibrillation is undetectable with an insulating barrier between the rescuers hands and the cadaver.

Section snippets

Ethic review

This protocol was reviewed by The University of Texas Health Science Center at San Antonio's Institutional Review Board for ethical consideration in human subjects research (Protocol Number: HSC20140411H). All subjects provided full informed consent prior to participation. A Licensed emergency physician and on duty EMS crew were on site at all times.

Study design and setting

This was a blinded prospective double-randomized (order of shocks and types of barriers) control study comparing a rescuer's ability to detect

Participation

Ten subjects participated in this study. There were a total of 100 defibrillations (30 J) delivered while the subject used bare hands, and 500 defibrillations (360 J) delivered while the subject used some type of insulating barrier. One-half of the defibrillations were actively transmitted to the cadaver. Two cadavers were utilized (Fig. 1).

Bare hands

With bare hands on the chest, 49 of 50 (98%) 30 J defibrillations were detected by the subject. Mean detection level was 3.2 of 10 (±2.2, 95%CI, 2.6–3.8) p  

Discussion

This study demonstrated that defibrillation was essentially undetectable with any level of insulating barrier between the rescuers hands and the cadaver. The data demonstrate the feasibility of continuous manual chest compressions throughout the resuscitation cycle as long as the rescuers wear even standard nitrile exam gloves. This is critical because of the hemodynamic consequences of stopping compressions. The ROC study group demonstrated the clinical impact of the preshock pause alone was

Conclusions

Structural firefighter gloves and compression decompression device prevent detection of a 360 J defibrillation of a cadaver during active chest compressions. Nitrile gloves or a neoprene pad essentially prevent (99%) responder's detection of a 360 J defibrillation on a cadaver. Defibrillation with bare hands on the chest was easily detectable even at a reduced energy level.

Conflicts of interest statement

Authors report no conflict of interest.

Acknowledgments

Internal funds were used to support this project, provided by Bulverde Spring Branch Emergency Services, Centre for Emergency Health Sciences, and the Department of Emergency Health Sciences, UTHSCSA.

The opinions or assertions contained herein are the private views of the authors, and are not to be construed as official or as reflecting the views of the United States Air Force or the Department of Defense.

Authors wish to extend their gratitude to the UT South Western Willed Body Program and the

References (16)

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Cited by (9)

  • Ex vivo evaluation of personal protective equipment in hands-on defibrillation

    2022, Resuscitation Plus
    Citation Excerpt :

    In the context of hands-on defibrillation, the risk to rescuer must be weighed carefully against the benefit to the patient. Some studies have demonstrated a favorable safety profile afforded by wearing clinical examination gloves during hands-on defibrillation.11,12,21 Lloyd and colleagues studied the leakage current through rescuers wearing clinical examination gloves with hands-on defibrillation and found leakage current to be below safety standards, with no shocks perceived by the rescuer.

  • The safety and efficacy of hands-on defibrillation in the management of adult cardiac arrest: A systematic review

    2020, American Journal of Emergency Medicine
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    Lloyd et al. concluded that HOD with clinical examination gloves is “feasible” and this trial was followed by several others that further evaluated the safety of the rescuer. Wampler et al. tested how perceptible electrical defibrillation was through one layer of nitrile gloves in a blinded cadaver study with a 360 J defibrillation through each cadaver and found that only 1 of 50 shocks were perceptible to rescuers, though they mention that their study was limited by the facts that electrical conduction may change as time elapses after death and that their environment for experimentation was clean and dry, which may be unrealistic during life [10]. For double-layer nitrile gloves, 3 of 50 shocks were perceptible to rescuers.

  • Cadaver models for cardiac arrest: A systematic review and perspectives

    2019, Resuscitation
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    No preparation or declotting is performed. In this systematic review, 16 (55%) studies used fresh cadavers, and these records studied six main research areas: airway management, seven studies (44%);24–30 mechanical properties of the chest, three studies (19%);17,31,32 haemodynamics, two studies (12.5%);33,34 defibrillation safety, two studies (12.5%),22,35 intraosseous access, one study (6%);36 and one study explored bispectral index monitoring and used a fresh cadaver for artefact control (6%).37 The main advantages reported of using fresh cadavers were: its accurate morphology and tissue conservation making it possible, for example, to reflect the conditions of endotracheal intubation, accurately estimate regurgitation risks in humans having CPR, obtain a stable transthoracic impedance over time and characterise thoracic viscoelastic properties.

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A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2016.03.019.

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