Mechanical vest from Hopkins may be tested on heart patients

September 09, 1993|By Jonathan Bor | Jonathan Bor,Staff Writer

A company spun off Johns Hopkins research is seeking federal approval to test a mechanical resuscitation vest in a national trial, estimating that the vest could save twice as many heart attack victims as conventional cardiopulmonary resuscitation techniques.

The vest, which wraps around the torso, inflates and deflates once each second. With each inflation, it exerts pressure evenly to all areas, restoring blood circulation.

Ten years in development, the vest is the invention of researchers at the Johns Hopkins School of Medicine. Last year, Hopkins licensed a Baltimore-based company, CardioLogic Systems Inc., to test and produce it.

Pending approval by the Food and Drug Administration, trials would begin by November on 300 to 400 patients in the early stages of a heart attack. The trials would take place at several hospitals -- but not at Hopkins, because the institution as well as researchers there hold equity shares in the company.

Dr. Henry Halperin, director of the cardiac mechanics laboratory at Hopkins, said the vest has a better chance of reviving patients and saving lives than manual CPR, which is successful 15 percent of the time.

The chief advantage, he said, is that the vest exerts pressure all around the torso, squeezing blood to the heart and brain more effectively than do hand compressions, which exert force in just one area.

"The more blood flow you generate during CPR, the more likely you are to save the victims," Dr. Halperin said.

He said the vest is much safer than the manual technique, which can fracture ribs and damage internal organs.

The vest is connected by two hoses to a 180-pound air pump, which stands on the floor and supplies rapid bursts of air. The vest maintains a small amount of pressure on the chest between compressions. On every fifth compression, however, it deflates completely.

The FDA application, to be filed later this month, will lean heavily on the results of earlier experiments appearing in today's New England Journal of Medicine. They showed that the vest generated more blood flow, restarted the heart faster and kept it beating longer than did standard CPR.

Those experiments, however, were limited to patients who had already failed standard CPR and were not expected to live more than a few days even with a successful resuscitation.

The proposed trial would involve patients who are considered good candidates for long-term survival. Half would be outfitted with the vest, while the other half would receive hand compressions.

To encourage the transfer of research to the marketplace, the university changed its conflict-of-interest rules a year ago to allow faculty and the university to hold equity in companies. CardioLogic is the first company set up under those rules.

Dr. Halperin said a price has not been set for the vest, which might cost from $5,000 to $30,000. As lighter models are designed, he said, the price could come down.

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