January 2003

• Automated external defibrillators at home
• Anemia sufferers now have expanding options for treatment

Automated external defibrillators at home

As you read this, someone somewhere in the United States is collapsing from a cardiac arrest. The odds are poor that she or he will survive this sudden disruption of the heart’s normal rhythm. Most of the 1,000 or so people who go into cardiac arrest each day die because they don’t get the treatment they need — an electric shock to the heart — fast enough.

Heart-shocking devices were once found only in hospitals and ambulances. Now they’re popping up in airports, movie theaters, fitness centers, casinos, malls, office buildings, and other places. These public versions, called automated external defibrillators (dee-FIB-rih-lay-tors), are so easy to use that sixth graders who have never seen one before can master their use in a minute or so, as shown in a 2002 study. This ease of use, combined with the fact that 3 in 4 cardiac arrests happen at home, have opened a national debate over whether it’s a good idea to have a defibrillator at home.The chances of surviving a cardiac arrest fall about 10% for each minute the heart stays in ventricular fibrillation. Shock the heart back into a normal rhythm within two minutes, and the victim has an 80% chance of surviving. Deliver that shock after seven minutes — the average time it takes an emergency medical team to arrive in many cities — and the odds are less than 30%. If someone near you goes into cardiac arrest, calling 911 is a must. Even if there’s a defibrillator nearby, you’ll need professional help as soon as possible. CPR is also important because it keeps blood flowing to the brain and other vital organs. Still, a home defibrillator could let you restore a healthy heart rhythm several crucial minutes sooner than emergency medical technicians.

Can home defibrillators help?

With a prescription from a doctor and $2,500 or so, you can buy a defibrillator for your home, office, or car at many large pharmacies or medical supply companies. The question is, should you? Experts in the areas of sudden cardiac arrest, emergency medicine, and public health don’t see eye-to-eye on this issue. Some argue that people who want to buy defibrillators for their homes should be able to do so without needing a prescription from a doctor. Others argue that people won’t maintain the devices so they will be ready when needed, or that most people would be better off spending some of the money on a health club membership and donating the rest to their local emergency response team.

Researchers have collected relatively little evidence on the benefits and risks of wider access to defibrillators. A few studies have examined their use in public places. One, published in the October 17, 2002, Journal of the American Medical Association, showed that 11 of 18 people who collapsed with ventricular fibrillation over a two-year period in Chicago’s three airports were revived, mostly by passers-by who used highly visible and well-marked defibrillators.

But their use at home is uncharted territory. One project, Neighborhood Heart Watch, is putting automated defibrillators in volunteers’ homes in Indianapolis neighborhoods. When there’s a call to 911 about a cardiac arrest in that neighborhood, it’s routed to both the emergency services and the nearest home with a defibrillator.

Another study, the Home Automatic External Defibrillator Trial, sponsored in part by the National Institutes of Health, aims to map out the benefits and risks. It will give home defibrillators to 3,500 heart patients and train their partners to use the devices. The partners of another 3,500 heart patients will get training in CPR, but no home defibrillator. The results aren’t expected until 2007.

Who should have one?

A home defibrillator would probably be a good investment for anyone who has survived a sudden cardiac arrest but who does not have a pacemaker capable of shocking the heart (an implantable cardioverter/defibrillator, or ICD). Owning this device might also make sense for someone with severe heart failure, unstable angina, or other severe forms of heart disease. So far, though, there’s no good evidence that home defibrillators will save lives in this group of people.

Training is a must

If you decide to buy a defibrillator for your home, or if you just want to be prepared for the chance you’ll someday need to use one in a public venue, make the time now to take a class on using this device.

Why bother to go through training when these machines have been designed for virtually mistake-free use? Several reasons. A class can help you use the defibrillator with confidence and speed. It can help you deal with unusual situations, such as where to apply the pads on someone with an implanted pacemaker, a medication patch, or a hairy chest. It will also teach you how to do CPR, an important part of the process.

The American Heart Association has developed a 3 1/2-hour course called “HeartSaver AED for Lay Rescuers and First Responders.” To find the closest training center that offers this course, call the AHA at 800-242-8721.

January 2003 Update

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Anemia sufferers now have expanding options for treatment

Anemia, the lack of oxygen-carrying red blood cells, can cause severe fatigue. Luckily, more of the people suffering from the disorder, namely those undergoing chemotherapy and recovering from bone marrow transplants, are finding help in recombinant erythropoietin therapy. This treatment involves injections or IVs of genetically engineered proteins to stimulate the body’s natural production of red blood cells, thus curing anemia.

Erythropoietin therapy for chemo patients

People who undergo chemotherapy to destroy fast-growing cancer cells often suffer from anemia because the treatment also destroys the cells that give rise to red blood cells. In July 2002, the Food and Drug Administration approved the use of an erythropoietic protein for the treatment of anemia related to chemotherapy.

This protein, Aranesp (darbepoetin alfa), works by promoting the formation of new red blood cells. Already in use to treat patients with anemia related to kidney failure, Aranesp is similar to EPOGEN and Procrit, two drugs currently used to treat anemia in chemotherapy patients. But Aranesp lasts roughly three times longer in the body. While patients may need an injection of EPOGEN or Procrit three times a week, Aranesp is needed just once weekly or every other week. This means fewer visits to the doctor for treatments by chemotherapy patients. Using Aranesp is also less expensive than EPOGEN and Procrit, although most insurers are likely to cover the cost.

Erythropoietin therapy for bone marrow transplants

Erythropoietin therapy is also beginning to show promise for the treatment of anemia in patients who receive donated bone marrow transplants. Bone marrow tissue produces new blood cells, and people receive a transplant of this tissue when their own bone marrow is unable to produce healthy blood cells. Transplant patients often require repeated blood transfusions to maintain healthy levels of hemoglobin, the oxygen-carrying protein in red blood cells. In previous studies, researchers have had limited success using very high, costly doses of erythropoietin therapy to stimulate red blood cell production in these patients. Now a study published in the June 2002 issue of Experimental Hematology shows low doses of erythropoietin therapy are quite successful at boosting and maintaining hemoglobin levels if timed correctly.

Researchers investigated the optimal timing and dosage for erythropoietin therapy in 34 patients who had received a bone marrow transplant. In the first trial, patients began receiving a high dose of erythropoietin daily immediately following the transplant. In the second trial, patients received a lower dose of the treatment three times per week beginning sometime between 2 months and four years following the transplant. Patients in the third trial began receiving a low dose of erythropoietin twice a week 35 days after transplant. If hemoglobin levels were considered insufficient (below 8 g/dL), patients received transfusions. To determine how well the erythropoietin worked, researchers measured the hemoglobin levels of the patients and recorded the number of transfusions required.

The researchers found patients in the first trial benefited little from the treatment compared to control patients who did not receive any treatment. Meanwhile, patients in the second and third trials typically did not need transfusions after just one week of the erythropoietin therapy. On average it took seven weeks for patients in the second trial and only four weeks for patients in the third trial to reach normal hemoglobin levels (12 g/dL).

While this study was small, the results suggest erythropoietin therapy is most successful after 35 days following transplant. The researchers believe this is when the bone marrow has recovered and is able to produce red blood cells. This study sets the stage for a larger, more comprehensive study of the use of erythropoietin therapy in bone marrow transplant patients.

January 2003 Update

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