Hypothermia for Myocardial infarction

Currently, the most exciting area of improving survival and neurologic function after cardiac arrest is hypothermia, a treatment first recommended at least a decade ago. Lack of enthusiasm for the treatment could stem from the fact that it does not involve a new drug or device, said Michael Sayre, MD, an associate professor in the department of emergency medicine at Ohio State University in Columbus.

In most communities, there has to be a local physician-advocate who wants to make it happen, he said. You also need a system in place to support it.

Hypothermia after cardiac arrest requires more than buy-in from the emergency department. It has to have support from intensive care unit doctors, cardiologists, and nurses. It takes a lot of effort to get the institutional direction changed so that the treatment is used routinely, Dr. Heard said.

Although he called hypothermia the most important advance in neurological protection in cardiac resuscitation, he noted that out-of-hospital initiation of hypothermia with cold saline infusion is another promising treatment.

It makes sense that earlier is better, and it's clearly been shown to be safe, but it is just a matter of whether there is an incremental benefit of starting cooling in the field, he said.

It's an exciting question to get sorted out worldwide, said Joseph Ornato, MD, a professor and the chair of emergency medicine at Virginia Commonwealth University Health Sciences Center in Richmond. Is it better to cool immediately after resuscitation? He said the Seattle group has worked out a simple, inexpensive way of doing this, and his group is getting ready to follow suit.

He said he is happy to see hypothermia becoming more widely accepted. I know the FDA is still struggling with it, and that there is some difference of opinion of when they will allow a device officially to have labeling that hypothermia is indicated. If we take the regulatory issue out and look at what the leading centers are doing in this area, it's clear that a lot of our centers are using it. We've been doing it for four years now. It's our standard of care.

Dr. Ornato said in the 30 years he has been involved in resuscitation research, he has seen a huge difference in not only patients who survive but survive neurologically intact. It's a different world, he said. It's a totally different world.

Hypothermia patients must be paralyzed because they shiver when they are cold, raising their body temperatures, and he said physicians have to pay attention to the brain during cooling because some patients have status epilepticus. You don't see them shake without the high-tech monitoring, he noted.

Other questions to be answered are whether the entire body should be cooled or only the brain, said Dr. Ornato. Some companies are working in animals with equipment that would cool only the brain, and he said some studies indicate that cooling during resuscitation benefits not only the brain but also the heart. Most of us think that the brain and heart are talking to each other, even during resuscitation. Some people think that cooling the brain may reduce the signals between the brain and heart and that makes the heart come out of cardiac arrest more easily. This is a whole new mechanism that we might be able to affect during resuscitation.