This article is more than 5 years old. Information may no longer be current.
Automatic chest compressor aids in treatment of cardiac arrest
The AutoPulse demonstrated improved hemodynamics and in some studies, increased survivability in hospital discharge rates.
Click Here to Manage Email Alerts
An automatic chest compression device called the AutoPulse aims to improve survivability in patients experiencing cardiac arrest while freeing the hands of emergency medical technicians and clinicians.
The American Heart Association recommends that a patient receive cardiopulmonary resuscitation immediately upon the first signs of an MI. The speed at which the AutoPulse (Zoll Inc.) can be deployed makes it useful for providing cardiac arrest patients with CPR-like chest compressions in the first crucial minutes of their care, according to Joseph P. Ornato, MD, professor and chairman of the department of emergency medicine at Virginia Commonwealth University’s Medical College of Virginia, Richmond.
The AutoPulse noninvasive cardiac support pump is designed to provide full chest compressions in place of the manual CPR traditionally administered by emergency medical technicians in route to the hospital. The device can be activated quickly and can be immediately applied to the patient in an emergency setting.
The device has a load-distributing belt attached to a battery-powered generator board that is placed under the supine patient. The load-distributing belt is wrapped around the chest of the patient, adjusted to whatever tensile level suits the patient, and the generator can then be programmed with any number and rate of chest compressions. The device reduces the fatigue of the emergency crew and allows them to work uninterrupted while the patient is transported to the hospital.
Clinical study of AutoPulse
|
Source: Zoll Inc. |
Findings from several studies have demonstrated the AutoPulse’s ability to improve overall hemodynamic function, as well as improve the rates of patient survival to hospital discharge.
Data from a 2004 study comparing hemodynamics in a porcine model using the AutoPulse vs. conventional CPR showed that the AutoPulse improved myocardial and cerebral blood flow, coronary perfusion pressure, right atrial pressure and overall hemodynamics to near pre-arrest levels. The data appeared in the Journal of the American College of Cardiology.
Results from an observational study published in the Journal of the American Medical Association suggested an association between higher survival to hospital discharge rates and use of the AutoPulse devices by emergency medical teams. The researchers enrolled 783 patients during the four-year course of the study. They treated 210 patients with the AutoPulse device.
“Our study was a analysis of our survival to hospital discharge results before and after switching from manual to AutoPulse chest compression rather than a randomized clinical trial,” Ornato told Cardiology Today. “Normally, that should carry much less scientific weight than results of a randomized clinical trial, but there were some problems with the randomized trial’s design and execution.”
The ASPIRE trials
Results of the AutoPulse Assisted Prehospital International Resuscitation (ASPIRE) randomized trial, published in the Journal of the American Medical Association, indicated that patients who used the AutoPulse device had lower survival rates than those who had received conventional CPR in route to hospitals. Procedural problems were also reported by the researchers, related to possible selection bias and discrepancies between patient responses during short periods and longer periods. It was also revealed that one of the major centers providing the majority of data for the study changed a protocol while the study was still underway.
“The observational study may have yielded better results in this case because it was carried out using the same operators from one cachement area (Richmond, Va.), whereas the clinical trial included many different operators from various centers, and thus all may have had slightly different ways of performing CPR or using the device,” said Uday N. Kumar, MD, said in an interview. Kumar is an adjunct clinical instructor of medicine in the division of cardiovascular medicine at the Stanford University School of Medicine and member of the Electrophysiology and Arrhythmia Disorders section of the Cardiology Today Editorial Board. “On the flip side, even though randomization should have helped to control for interoperator variability, the results of the randomized trial may actually be more indicative of reality, because different people are likely to do the same procedure or use a given device differently. The idea of operator and situational variance may also be reflected in the finding that the survival rate for cardiac arrest is better in certain places than in others.”
Consequently, the results of a second ASPIRE trial, currently being conducted in Europe, are anticipated in the near future to address some of these design problems and to provide clearer safety and efficacy data for the AutoPulse device.
“The bottom line is that the randomized trial had some issues with it, and, unfortunately it leaves us in a situation where we have a randomized trial that really should trump out simple observation both before and after. But because of the way it had to be conducted, it leaves us a bit uncertain. What all of us feel is necessary is another study to clarify the broader applicability of this device,” Ornato said. - by Eric Raible
Dr. Ornato is on the science advisory board for ZOLL Circulation, but receives minimal compensation for such activity.
For more information:
- Halperin H, Paradis N, Ornato J, et al. Cardiopulmonary resuscitation with a novel chest compression device in a porcine model of cardiac arrest. J Am Coll Cardiol. 2004;44:2214-2220.
- Halstrom A, Rea T, Sayre M, et al. Manual chest compression versus use of an automated chest compression device during resuscitation following out-of-hospital cardiac arrest. JAMA. 2006;295:2620-2628.
- Ong M, Ornato J, Edwards D, et al. Use of an automated, load-distributing band chest compression device for out-of-hospital cardiac arrest resuscitation. JAMA. 2006;295:2629-2637.