會議小組共同主持人、美國過敏、氣喘與免疫學院理事長候選人Nova Southeastern大學助理臨床教授、佛羅里達州羅德岱堡開業醫師Dana V. Wallace提出病患對SIE的另一個顧慮：當我問病患何以不使用腎上腺素時，他們表示「因為我不想去急診」。Wallace醫師指出，在美國，並非每個人都可以負擔昂貴的救護車費用，所以他們不想花費。
More than Half of Patients With Anaphylaxis Delay Seeking Medical Attention
By Jacquelyn K. Beals, PhD
Medscape Medical News
December 8, 2009 (Buenos Aires, Argentina) — A study assessing patients' use of medication for anaphylaxis and reasons for their delay in seeking medical attention indicates that nearly two thirds of patients with prescriptions for self-injectable epinephrine (SIE) failed to use it before reaching the emergency department.
In the United States, 1000 to 2000 people die each year as a result of anaphylactic reactions — often fatal food-related anaphylaxis in adolescents and young adults — and many of these fatalities are preventable. The new study was presented here at the World Allergy Organization XXI World Allergy Congress by Wyatt W. Decker, MD, from the Department of Emergency Medicine, Mayo Clinic College of Medicine, in Rochester, Minnesota.
Dr. Decker noted the lack of studies on anaphylaxis that address patients' knowledge about their disease. He pointed to education as a key factor in preventing delays in patients' arrival at the emergency department and in their use of SIE. Information for the current study was obtained from a questionnaire given while patients were at the emergency department and from telephone follow-up.
The study population consisted of 42 patients (26 female) arriving at the emergency department with symptoms of anaphylaxis. Ages ranged from 13 to 52 years (median, 30 years). Slightly more than half of those surveyed (22 individuals) reported a delay in coming to the emergency department, with 15 saying they expected the symptoms to go away. However, the severity of an anaphylactic reaction is impossible to anticipate, and treatment could come too late, Dr. Decker said in his talk. "Mild reactions in the past can lead to severe reactions in the future," he reminded the audience.
Causes of anaphylactic reactions in the study population included foods, insects, medications, other allergens, or "unknown," with time to symptom onset ranging from 6 to 39 minutes (median, 15 minutes). Nearly all patients (95.2%) used some medication before obtaining medical care, including antihistamines (19 patients), albuterol inhalers (4 patients), and nebulizer (1 patient).
Dr. Decker's report focused on 19 patients with SIE prescriptions. Of the 14 patients who had SIE with them at the time of the anaphylactic reaction, only 7 used it.
"The most common cause anecdotally [for not using SIE] appears to be that patients want to see if they get better before they give themselves a shot of epinephrine," Dr. Decker told Medscape Allergy Clinical Immunology. "Or they believe that if they give themselves a shot then they have to come to the hospital, so they're reluctant to give themselves the shot. This is not what we want."
The questionnaire asked patients their reasons for not using SIE: 3 patients did not consider their symptoms serious enough; 1 was unable to find their SIE; 1 felt it was unsafe to use; 1 was unsure when SIE use was indicated; and 1 had SIE that was past its expiration date.
Asked by Medscape Allergy Clinical Immunology whether using SIE increased the need for patients to go to the hospital, Dr. Decker indicated this was not the case. "The most important indication of going to the hospital is the severity of the reaction. You have to activate [SIE] early because the [patient] can't tell yet if [their reaction] is going to be dangerous or not. So by getting themselves to the hospital or having prehospital providers come to them, it's like insurance. If it gets desperate, then the experts are there. If they wait, there may not be time.?.?.?. The few fatal cases of anaphylaxis that we see are often in people who waited; then it gets so severe that they call for help but it's too late. That's the danger with waiting," Dr. Decker emphasized.
In very rare cases, epinephrine's effect on heart rate can trigger myocardial infarction. When these cases are examined, as they have been by other researchers, nearly all are inadvertent overdoses of epinephrine. "It's almost impossible to do that with an EpiPen or SIE because they're the appropriate dose," noted Dr. Decker. Patients are a little afraid of the epinephrine, probably too much so. "It should just be given and then they should come to the hospital," he said.
Session comoderator Dana V. Wallace, MD, a private practitioner in Fort Lauderdale, Florida, assistant clinical professor at Nova Southeastern University, and president-elect of the American College of Allergy, Asthma Immunology, identified another patient concern about SIE: "When I ask why patients don't take the epinephrine, they say 'Because I didn't want to go to the emergency room.' In the United States, not everyone is covered for the expensive ambulance ride, so they don't want to pay for it," Dr. Wallace said.
"We have to emphasize that the worst of all possible errors is not to give it and not go to the emergency room," Dr. Wallace told Medscape Allergy Clinical Immunology. "So at least if they know to take it, please do administer it, even if for some poor reason they choose not to go to the emergency room." She also noted that some people are afraid to self-inject or afraid to inject their child.
"There was one very nice study where an allergist took a group of healthy young patients, adolescents and adults, and asked them to self-administer [SIE] in a controlled environment in his office, when they were not having anaphylaxis. It seemed that they and their families all walked away much happier because they knew they could do it and that it wasn't going to cause a horrible side effect," said Dr. Wallace. "I think at times maybe that's the message for healthy people we should try," she concluded.
Dr. Decker reports receiving funding from the not-for-profit Food, Allergy, and Anaphylaxis Network. Dr. Wallace reports being on the speakers' bureau for Schering-Plough, Aventis, Pfizer, and Merck, and is on the advisory board for AstraZeneca.
World Allergy Organization XXI World Allergy Congress (WAC): Abstract?434. Presented December?7, 2009.
