Vasopressin works better than adrenaline for some types of cardiac arrest

Main Category: Public Health
Article Date: 10 Jan 2004 - 0:00 PDT


People with a hard-to-treat type of cardiac arrest are three times as likely to survive if they are given a drug called vasopressin than if they receive the standard emergency treatment, adrenaline, doctors in Europe are reporting.

Experts say the information may change the way doctors around the world treat cardiac arrest, which has had dismal survival rates. The condition, often caused by diseased arteries, leads to more than 600,000 sudden deaths a year just in North America and Europe, including about 1,000 a day in the United States.

More than half the deaths are in people younger than 65. Cardiac arrest, which is not the same as a heart attack, is a sudden stopping of the heart. But a severe heart attack can lead to cardiac arrest.

The new findings are from a study of 1,186 people in Austria, Germany and Switzerland whose hearts suddenly stopped. The study, directed by Dr. Volker Wenzel of the University of Innsbruck, in Austria, included 44 medical teams and is being published today in The New England Journal of Medicine.

People in the study were not in the hospital when they collapsed, but were treated by emergency teams and then taken to hospitals. The study did not include patients who were revived by electrical shocks delivered by defibrillator machines.

It did include patients in whom a defibrillator had failed or was not used because they did not have the kind of abnormal heart rhythm that a shock would help. The patients received the standard emergency treatment for cardiac arrest, including chest compressions and rescue breathing.

To help restart their hearts, the patients were assigned at random to receive either vasopressin or adrenaline, which is also known as epinephrine. If two shots of either medicine did not work, doctors could then give adrenaline, even the patients who had already received it.

The two drugs work in similar ways, by constricting blood vessels and raising blood pressure, which plummets in people with cardiac arrest.

Both are naturally occurring hormones; adrenaline is made by the adrenal gland, vasopressin by the pituitary. Adrenaline has been used for heart problems for about 100 years.

Over all, the survival rate was the same for the two drugs, 9.9 percent. But they found a striking difference among patients with a condition called asystole, in which there is no pulse and no electrical activity in the heart.

It is notoriously hard to treat, doctors say. Asystole causes 20 percent to 40 percent of the sudden deaths in the United States. In the vasopressin group, 12 of 257 survived, 4.7 percent, in contrast to only 4 of 262, 1.5 percent of those who got adrenaline.

There was also a sharp difference among the patients who needed more than two shots of medicine to get their hearts going again and were given extra adrenaline.

That group amounted to nearly two-thirds of the patients in the study. In those who received vasopressin first, 23 of 369 patients survived, 6.2 percent, as compared with 6 of 355, 1.7 percent, in those whose first two shots were adrenaline.

In an interview, Dr. Wenzel said he had already changed the way he treated patients. Now, he gives nearly all adults with cardiac arrest both vasopressin and adrenaline.

'Get it in there, bang bang, and you either save a life immediately or you don't,' he said.

Researchers say vasopressin may work better than adrenaline in some cases because it does not deplete desperately needed oxygen in the heart and brain, whereas adrenaline does.

Vasopressin shifts blood flow away from the skin, legs, abdomen, and muscles, and toward the brain and heart, Dr. Wenzel said.

'I think that's simply the advantage,' he said. 'Your liver or skin can spare 15 minutes of not being perfused, but if your heart or brain is not perfused for 15 minutes you're just flat dead.'

Other researchers said the results were an important advance even though the overall survival rate was still low.

A spokesman for the American Heart Association, Dr. Vinay Nadkarni said the heart association, which issues resuscitation guidelines, would be examining the study and considering whether to make changes based on it. One concern, he said, is that emergency medical teams in Europe, unlike those in the United States, include physicians. Will paramedics be able to achieve the same results? he asked.

'We're not sure, but it has to be investigated and looked at,' Dr. Nadkarni said.

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