CPR: inflatable investment.

CPR: Inflatable investment

The sight of emergency medical personnel pushing against the chest of a heart attack victim may become a thing of the past if a new method of cardiopulmonary resuscitation (CPR) proves successful in expanded trials.

In traditional CPR, rhythmic pressure applied to the chest decreases chest volume. That increases pressure in the thoracic cavity, forcing blood to the heart and brain during the critical minutes before spontaneous respiration and heartbeats can be restored. But the intense local pressure near the sternum also can cause life-threatening trauma to the rib cage and lungs.

Joshua E. Tsitlik, Henry Halperin and their colleagues at the Johns Hopkins University School of Medicine in Baltimore have devised a computer-controlled, inflatable vest that distributes bursts of pressure equally around the circumference of the chest and back. The vest provided a 100 percent survival rate in seven dogs suffering from cardiac arrest, without causing any of the CPR-induced injuries observed in dogs getting traditional CPR. In experiments with human patients who had failed to respond to standard CPR, the vest increased blood pressure to nearly double the levels achieved using classical chest compressions.

Those results "give us a real strong feeling" that resuscitation success rates can be significantly improved and that the degree of brain damage due to short-term oxygen loss can be reduced, Tsitlik said at the Biomedical Engineering 25th Anniversary Symposium, held at Hopkins last week. The team recently received FDA permission to use the vest in initial resuscitation attempts on victims of cardiac arrest.