Five years after New England Journal of Medicine studies showed that lowering the body temperature of those resuscitated after cardiac arrest could protect the brain and four years after the American Heart Association and the International Liaison Committee on Resuscitation recommended the “chilling” treatment, few hospitals have signed on.
“People aren't doing it routinely,” said Robert W. Neumar, MD, PhD, an associate professor of emergency medicine at the University of Pennsylvania School of Medicine, “but there are people who are and who feel it is important.”
The original studies were proof of concept, he said. “Now we are in 2007, five years after the publication, and a minority of hospitals are doing this.”
“Look at the data,” said Michael Sayre, MD, an associate professor of emergency medicine at the Ohio State University School of Medicine in Columbus. “The survival rate with good neurological outcome was about 55 percent with hypothermia therapy and 40 percent without. It means you have to give six people hypothermia to have one more alive with good neurological outcome at six months.”
The patients in the studies had cardiac arrest after ventricular fibrillation and were resuscitated, but were in a coma or at least unable to respond to verbal commands afterward. “For others, the benefit is probably much smaller, but we really are still learning how to pick which other kinds of patients might benefit.”
The reasons for the lack of acceptance are both simple and complicated, said emergency physicians who have championed hypothermia for this indication. “There isn't anyone out there promoting it,” said Dr. Sayre. “It's not like a new drug that gets introduced with a sales representative knocking on the door.”
Dr. Sayre said most communities need a physician advocate to make it happen, largely because an individual physician would find it difficult to do alone. “You need a system in place to support it. If you are given a drug, you can just try it out on a patient,” Dr. Sayre said. “This patient requires that you also have intensive care unit doctors, cardiologists, and nurses across the hospital on board. It takes a lot of effort to get the institutional direction change so that the treatment is used routinely. I speak from experience. In my case, it took about three years to get it to happen.”
Patients unable to follow commands in the emergency department are eligible for cooling treatment, although he said it is impossible to predict in the ED who will wake up and do well and who will not. “You pool all the patients. Many will not survive, but there will be some who survive because of the treatment,” said Dr. Sayre.
Figure. DR. MICHAEL ...Image Tools
The AHA-ILCOR recommendation aims at lowering the body temperature to between 89.6°F and 93.2°F as soon as possible after resuscitation and continuing that for 12 to 24 hours. Researchers still must determine the best methods of cooling, the optimal time for cooling, and the best patient population.
“Everyone in the hospital has some cooling technology,” said Dr. Sayre. “We all have cooling blankets. There are also higher tech ways of doing it, but you can do it low tech with ice bags and cooling blankets.” Higher tech methods may have advantages — better temperature, less nursing involvement — but “it doesn't mean you cannot do it today with cooling equipment you already have.”
Dr. Sayre said the treatment can be harmful if given to the wrong patients, and although some suggest cooling patients before they reach the hospital, he warned that getting the hospitals on board should be accomplished first.
“Prehospital is the next step, but it makes little sense to cool in the ambulance and then get to the hospital where they warm them up. That has happened. The staff did not understand what was going on so they warmed the patient up. You don't want that to happen.”
Continuum of Care
Dr. Neumar agreed that a continuum of care is needed. “The problem is that the patient resuscitated after a cardiac arrest goes through a number of providers in different locations in the first 48 hours — prehospital care, emergency department providers, the cath lab, then the cardiac care unit or the ICU,” he said. “All nursing staff and technicians have to be on board and understand how it needs to done. You have to have a cooling system to keep them cold the whole time. The staff has to be trained in how to do it. It's a huge educational endeavor.”
He said an institution has to have a champion who is willing to spend two years making the treatment happen, adding that the logistics of implementation are the biggest barrier. “You have to get everyone in the same room and show them the data that this works for the right patient,” said Dr. Sayre. “For that type of patient, the effect is large. It really matters for that group of patients. I think the places that have successfully implemented the treatment have done so by focusing on that group of patients. You can get your foot in the door. Once the hospital has made the commitment, then we decide how we do it.”
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Dr. Sayre said the hospital is typically not the barrier, but is mostly physicians who do not know about it. “Because they do not have the knowledge, they do not push for it. Most people find, when they have treated two or three of these patients, that it is not hard. They are comfortable after that. It's helpful to have someone available to call, maybe someone at another institution,” he said.
Not everyone is convinced that the treatment is effective, said Dr. Neumar. The U.S. Food and Drug Administration has yet to approve a device for cooling for this indication, he said.
Many questions remain, said Dr. Neumar. There has been no large, multi-institutional trial that looks at a protocol for post-cardiac arrest treatment that includes hypothermia. Although there is evidence that hypothermia in cardiac arrest has measurable benefits in survival and neurological outcomes, experts do not know the optimal times it needs to be started, the optimal temperature or duration of cooling or the specific patient subpopulation that benefits.
The treatment also may have benefit for organs other than brain, he said. Dr. Neumar is trying to address some of these questions in his laboratory, but questions awaiting answers should not deter physicians from implementing cooling. Dr. Sayre anticipates that acceptance will come. “The average amount of time between when an intervention is proven to work and when it is accepted is about 10 years. Hypothermia is halfway there,” he said.
© 2007 Lippincott Williams & Wilkins, Inc.