By Michelle Miron
Kalamazoo Gazette
Copyright 2007 Kalamazoo Gazette
All Rights Reserved
KALAMAZOO, Mich. — A cardiac-arrest victim is rushed to the hospital in an ambulance but has not had a heartbeat in 15 minutes.
Emergency medical technicians start using cardiopulmonary resuscitation, reintroducing oxygen in an attempt to save the patient.
Is it possible CPR could kill the patient instead?
Possibly, suggests ongoing research by a University of Pennsylvania physician.
Traditional wisdom has it that patients whose hearts have stopped should be treated with CPR, followed, if needed, by jolts with defibrillators and injections of the hormone epinephrine to force heart beats and to infuse heart cells rapidly with oxygen.
But that sudden, intense infusion actually might kill living cells, says Dr. Lance Becker, an authority on emergency medicine at the University of Pennsylvania, who has since become director of the school’s newly created Center for Resuscitation Science.
Becker’s theory: Mitochondria defense mechanisms within cells interpret the newly oxygenated cells to be cancerous and begin killing them off.
“What we found when we studied oxygen deprivation in cells astounded us,” Becker said in a press release from the University of Pennsylvania School of Medicine. “When cells are deprived of oxygen for an hour, there is only 4 percent cell death. After four hours, cell death is only around 16 percent. The amazing thing was once we reintroduced oxygen to the cells, they died off rapidly to almost 60 percent cell death.
“We concluded that the reintroduction of oxygen must be handled carefully for the majority of cells to survive. Our studies will be concentrating on ways to prepare cells deprived of oxygen for the reintroduction of oxygen.”
Instead of flooding the heart with oxygen, Becker says, doctors should slow the patient’s metabolism and blood flow and aim for a more gradual oxygen uptake.
Becker’s cell-death theory was substantiated by a four-hospital study published in 2006 by the University of California. Of 34 patients studied who had suffered sudden cardiac arrest, 80 percent lived when they were treated using methods that closely controlled blood circulation to the heart during resuscitation. One study that used more traditional resuscitation methods yielded only a 15 percent survival rate, according to Newsweek magazine.
In further studies, Becker plans to look more closely at the benefits of cooling cardiac-arrest patients immediately after a heart attack in order to reduce cell-death rates. The American Heart Association recently recommended that every cardiac-arrest patient “who qualifies” should undergo a temporary cooling process.
The process, called therapeutic hypothermia, is already being used by Bronson Healthcare Group and Borgess Medical Center.
Over the past two years, both hospitals have bought and begun to use equipment called the Arctic Sun Temperature Management System, which quickly cools down cardiac-arrest victims so their brain and heart cells aren’t infused with too much oxygen during recovery.
In the next several months, Borgess plans to invest in several more of the systems, said Dr. Paul Lange, an intensive-care physician and director of clinical care at Borgess. The system is manufactured by a Louisville, Ky.-based company called Medivance Inc.
It works through the use of a control module and display unit attached to specially designed pads that circulate temperature-controlled water. The pads are wrapped around a sedated patient in order to cool the body to a range of 89.6 degrees to 93.2 degrees Fahrenheit for the first 24 hours of recovery. He or she is closely monitored because of the extra risk of uncontrolled shivering, seizures, infection, blood clotting and electrolyte imbalances. Then, over the next 20 hours, the patient is gradually rewarmed using the same equipment.
Bronson also is using a product that cools the blood intravenously using catheters combined with electronic cooling equipment. The equipment, made by an Irvine, Calif.-based firm called Alsius Corp., is used on critical-care neurological patients in addition to cardiac-arrest patients, according to Jason Manshum, Bronson public-relations and media specialist.
Becker said his theories may have further implications for the extension of brain function during periods of resuscitation. “Many of the things we see in the heart are also true in the brain,” he said in the press release from the University of Pennsylvania School of Medicine.