Hypothermia Protocol Saves Sudden Cardiac Arrest Patients
Every year, approximately 250,000 Americans die from sudden cardiac arrest and according to the American Heart Association, approximately 95 percent die before reaching the hospital. Of the 5 percent who make it to an emergency department, only half are still alive 24 hours later. Time is of the essence when cardiac arrest occurs.
According to a 2003 study by the University of Pittsburgh School of Medicine, cooling the body temperature to levels consistent with hypothermia improves survival after sudden cardiac arrest and also promotes growth factors important for the brains recovery.
"The human brain solely relies on oxygen and glucose to live, and the lack of either can cause profound devastation," said Tim Ellender, MD, emergency medicine and critical care physician with Methodist Hospital's Emergency Medicine and Trauma Center and co-director of the Emergency Medicine-Critical Care Fellowship.
To improve the outcome of its cardiac arrest patients, Methodist Hospital assembled a collaborative team that drafted and implemented a hypothermia protocol designed to increase the oxygen supply and reduce oxygen consumption in the brain, with the goal of improving neurological function upon survival. Hypothermia decreases the body's metabolic rate 6-7 percent for every 1 degree Celsius decrease in body temperature.
Methodist's hypothermia protocol is used for patients with return of spontaneous circulation who are unresponsive or not following basic commands after cardiac arrest.
The hypothermia protocol is a temperature management algorithm that cools the body's core temperature from the normal 37 degrees Celsius to 32-34 degrees Celsius within approximately 2-3 hours. The patient is maintained at this temperature for 24 hours, in an effort to stop or slow the destructive effects that occur after a cardiac arrest and improve neurological function. After being cooled for 24 hours the patient is slowly rewarmed back to normal body temperature.
A temperature control unit, in combination with thin, hydro-gel pads that fit the body, facilitates rapid cooling by allowing direct contact of the cold water with the patient's skin. This accelerated cooling is difficult to achieve and maintain by traditional methods such as cooling blankets or ice packs. This non-invasive technique allows quick initiation of the cooling protocol, is highly effective and alleviates the risk of complications that accompany invasive techniques. Combined with simple maneuvers to initiate cooling, this technique has led to remarkable reductions in time to goal temperature achievement.
From January through September 2008, 51 cardiac arrest patients have been treated with induced hypothermia; many upon arrival to Methodist's Emergency Department. As of October 1, Methodist has had a 33 percent survival rate. The surviving 17 patients have had Glasgow Coma Scale Scores of 14-15 (normal neurological function) upon discharge from the hospital.
Continued Dr. Ellender, "It is important for us to translate our research and knowledge to the bedside, and we will continue to analyze this process and seek input and collaboration so that Methodist can continue offering its patients the highest quality healthcare and outcomes."