Elsevier

Resuscitation

Volume 73, Issue 1, April 2007, Pages 86-95
Resuscitation

Clinical paper
Out-of-hospital cardiopulmonary resuscitation with the AutoPulse™ system: A prospective observational study with a new load-distributing band chest compression device

https://doi.org/10.1016/j.resuscitation.2006.08.027Get rights and content

Summary

Objective

To evaluate the effectiveness, the safety, and the practicability of the new automated load-distributing band resuscitation device AutoPulse™ in out-of-hospital cardiac arrest in the midsized urban emergency service of Bonn city.

Study design

Prospective, observational study.

Methods

Measurements of effectiveness were the proportion of patients with a return of spontaneous circulation (ROSC) and end-tidal carbon-dioxide (etCO2) values during cardiopulmonary resuscitation (CPR). The indications of safety was the proportion of injuries caused by the device, and practicability was assessed by the measurement of the time taken to setup the AutoPulse™.

Results

Forty-six patients were resuscitated with the device from September 2004 to May 2005. In 25 patients (54.3%) ROSC was achieved, 18 patients (39.1%) were admitted to intensive care unit (ICU), and 10 patients (21.8%) were discharged from ICU. End-tidal capnography showed significantly higher etCO2 values in patients with ROSC than in patients without ROSC. The mean time to setup the AutoPulse™ was 4.7 ± 5.9 min, but activation of the device after arrival at the scene in 2 min or less was possible in 67.4%. No injuries were detected after use of the AutoPulse™-CPR.

Conclusion

The AutoPulse™ system is an effective and safe mechanical CPR device useful in out-of-hospital cardiac arrest CPR. Automated CPR devices may play an increasingly important role in CPR in the future because they assure continuous chest compressions of a constant quality.

Introduction

During cardiopulmonary resuscitation (CPR), adequate perfusion of the heart and the brain is needed to reestablish spontaneous circulation and to achieve survival with a good neurological outcome. If manual chest compressions are performed during CPR, the blood flow to the “vital organs” is generally impaired. Even if trained health personnel provides manual CPR, the blood flow in the brain is reduced to approximately 30–40% of the normal blood supply and in the heart to 10–20%.1 Vital organ blood flow may be even more reduced if the quality of the manual chest compressions is inadequate, because of incorrect compression rate or depth, or frequent interruptions. Suboptimal chest compressions correlate with a poor return of spontaneous circulation,2, 3 and interruptions to chest compression-generated blood flow are detrimental.4, 5 Improved survival of patients with out-of-hospital cardiac arrest was recently reported by Kellum et al. using a CPR protocol minimising the rate of interruptions of chest compressions.6 A potential solution to overcome the difficulties of suboptimal chest compressions and CPR interruptions may be the use of automated mechanical CPR devices.

The first mechanical CPR device introduced to clinical and preclinical application, the “Thumper” (Michigan Instruments, USA), was a mechanical chest compressor using a piston driven by pressurised air and it has been used since the late 1970s.7 Since then, various devices have been developed. In the present study, the AutoPulse™ system (Zoll Circulation, Chelmsford, MA, USA), a recently introduced device, has been assessed in a prospective observational trial in an urban emergency system. The AutoPulse™ is a fully automated CPR device that uses a load-distributing, broad compression band that is applied across the entire anterior chest. Previous animal and human studies demonstrated an improvement of haemodynamics and short term outcome using the AutoPulse™ technique compared to standard CPR performed by manual chest compressions or using the Thumper.8, 9, 10, 11 In the present observational study, resuscitation success rate was determined by achievement of the return of spontaneous circulation (ROSC), subsequent haemodynamics during AutoPulse™-CPR and long term outcome of the patients. Since invasive monitoring of patients with out-of-hospital cardiac arrest is not feasible, we used end-tidal carbon-dioxide (etCO2) as an indirect measurement of cardiac output.12 The patients admitted to an intensive care unit were visited daily for the first 3 days after admittance, and the hospital was regularly called until discharge or death. At discharge, the neurological state was evaluated by the attending physician using the Glasgow–Pittsburgh cerebral performance category (CPC), and 6 months after discharge, the patients or the relatives were called again for information about their further recovery.

Section snippets

Study design

The study was approved by the ethical committee of the University of Bonn. We conducted a prospective observational study with the new chest compression device AutoPulse™ on out-of-hospital cardiac arrest patients in the EMS system of Bonn city. Inclusion criteria for the study were aged 18–85 years, and cardiac arrest of non-traumatic origin. Pregnant patients were excluded. The decision to apply the AutoPulse™ system was made individually by the emergency doctors at the scene. Patients

Patients, cardiac arrest, and CPR characteristics

The study was performed in the EMS system of Bonn from September 2004 until May 2005. During this period, the AutoPulse™ was applied in 46 patients during CPR. The patients demographic data such as mean age, sex, and mean weight are given in Table 1. In patients resuscitated with the AutoPulse™, 63.0% of the cases cardiac arrest was witnessed, and in 30.4% bystander CPR was performed (Table 1). The initial ECG-rhythm was asystole in 52.2%, ventricular fibrillation or ventricular tachycardia in

Discussion

We performed a prospective observational preclinical study with the new load-distributing band chest compression device AutoPulse™ (Revivant Corporation, Sunnyvale, CA, USA) in the EMS system of Bonn city. Primary goals of the study were to verify the effectiveness, safety, and practicability of the automated mechanical resuscitation device in out-of-hospital cardiac arrest. The effectiveness was shown by the number of patients with ROSC and by the measurement of end-tidal CO2 during CPR. The

Conclusions

In conclusion, we presented operating experience and resuscitation success and survival rates after out-of-hospital cardiac arrest cardiopulmonary resuscitation with the new load-distributing band chest compression device AutoPulse™. In our observational preclinical study, the AutoPulse™ system proved to be an effective and safe mechanical CPR device for use in out-of-hospital cardiac arrest CPR. Automated CPR devices may play an increasingly important role in CPR in the future because they

Conflict of interest

The authors confirm that they have no financial interest in Zoll Circulation or other conflict of interest in performing the presented study.

Acknowledgements

We would like to thank the emergency doctors of the University Clinics of Bonn and the staff of the emergency medical system of Bonn for cooperation in our study.

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    A Spanish translated version of the summary of this article appears as Appendix in the final online version at 10.1016/j.resuscitation.2006.08.027.

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