The Bowtie Concept

Dr. Ornato said he is more optimistic about the future of research although he was also a member of the committee that published the recommendations on emergency research. He sees a real future in what he calls the bowtie concept of cardiac arrest and resuscitation. The knot on the bowtie is the cardiac arrest itself.

What we are using as a paradigm is that one of the wings, the one that comes before the cardiac arrest, is an opportunity in some cases to intervene to actually prevent the cardiac arrest. There is a movement afoot to establish a medical emergency team in hospital arrest applications in the emergency department and in prehospital care. We are trying more and more to recognize the early warning signs that the patient is in danger of going into cardiac arrest. In the hospital now, we are creating teams of physicians, nurses, and respiratory therapists - a medical emergency team - for someone whose vital signs are changing. We hope to empower health care providers to intervene and in the future extend this to prehospital care. We want to encourage the patients and their families to call sooner. If we can prevent a cardiac arrest, that's always going to be better.

On the other side of the bowtie is post-resuscitation care, he said. That's where the whole issue of hypothermia is coming in.

The newest changes in the CPR guidelines that promote quality resuscitation with fewer interruptions are exciting, said Dr. Ornato. In Seattle, where the teams began using the guidelines before they were published, survival increased significantly, he said. (Circulation 2006;114:2760.) It was the first affirmation that this is making a meaningful difference in survival, he said.

The understanding that only one in four people in cardiac arrest is in ventricular fibrillation or ventricular tachycardia has changed practice, he said. That's why there is renewed emphasis on better quality CPR but also the increasing evidence that it makes a big difference in survival, he said.

Dr. Ornato said new studies of drugs, including amiodarone in aqueous form, may prove valuable. Using the aqueous form of amiodarone avoids the hypotension associated with the current form of the drug, he said. He said another potentially valuable drug to be studied is estrogen. One of the projects we are looking at is the potential of large doses of Premarin injected intravenously during resuscitation.

He said researchers are mining the National Registry of CPR for information on the fate of males versus females cradle to grave during resuscitation. It looks as though the survival of children - boys and girls - is virtually identical until women start maturing. Then survival of women stays higher than that of men until age 55. It suggests that the hormonal milieu is important. In animal models of trauma and cardiac arrest, there is evidence that a single dose of estrogen for men and women could be protective, particularly of the brain.