Home monitoring after anaphylaxis, epinephrine use recommended over emergency response
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Although current guidelines recommend calls to emergency medical services and ED visits in response to anaphylaxis, home management may be preferable in many cases, according to a literature review.
“We wanted to explore the literature to determine if all patients suffering from an anaphylactic episode need to go to the ED following the use of auto-injectable epinephrine,” John J. Oppenheimer, MD, clinical professor of medicine at UMDNJ Rutgers University School of Medicine and a Healio Allergy/Asthma Peer Perspective Board Member, told Healio.
Once anaphylaxis begins, epinephrine should be administered immediately, the authors wrote in The Journal of Allergy and Clinical Immunology: In Practice. But telling patients that they should call emergency medical services (EMS) after administering the medication may inadvertently cause delays in administration due to the anxiety and downstream expenses of making that 911 call.
“Some patients actually delay or avoid use of epinephrine for fear of needing to next go to the ED,” Oppenheimer said. “Studies show that early use of epinephrine is truly lifesaving.”
Instead, the authors called for selecting, educating and provisioning appropriate patients with the correct medications for self-management and treatment of anaphylactic events to decrease the necessity of ED visits and improve outcomes via prompt epinephrine administration.
According to the authors’ proposed algorithm, candidates for self-management at home would need to be capable and adherent or have immediate access to a caregiver or individual who could provide appropriate assistance. Also, these candidates would need immediate access to at least two doses of epinephrine.
These candidates further would need a clear understanding of the risks and benefits of self-management. However, the authors cautioned that these recommendations would only apply to home management and not to school, daycare, restaurant or work environments.
Benefits of at-home monitoring
Guidelines recommend a minimum of two doses of self-injectable epinephrine, as 98% of anaphylactic reactions respond to two doses or less. More than 95% of patients who have these doses should be able to manage their anaphylaxis without risk, the authors wrote.
Plus, ambulances respond in approximately 7 minutes, with times doubled in rural areas. Most anaphylactic events would respond to epinephrine administered at home or resolve spontaneously before EMS would arrive, according to the authors.
Fatal anaphylaxis only occurs at a rate of 0.5 to 1 incident per million person-years, the authors wrote, with rates differing by allergen. Food is the least common allergen implicated in fatal anaphylaxis, often due to delayed epinephrine administration or risky behavior. Cardiovascular disease and older age have been implicated in drug-induced fatalities.
Meanwhile, patients who do go to the ED may receive inappropriate or unnecessary care, the authors wrote. In one study, only 7% of patients received epinephrine in the ED, while another reported a 50% administration rate, as ED physicians often rely on second-line agents to treat significant allergic reactions.
Guidelines then suggest clinicians “strongly consider” observing these patients afterward, with varying periods based on patient history, severity of symptoms and risk factors, with discharge after an hour of asymptomatic observation for patients without severe risks.
Data were limited, the authors continued, but the costs of calling EMS and visiting the ED after administering epinephrine at home were significantly higher than watchful waiting.
In a study that used a Markov model simulation to investigate the cost-effectiveness of calling EMS and undergoing subsequent ED evaluation for peanut-allergic children, researchers calculated a per-patient fatality risk associated with early EMS use of 1.2×10-6 over 20 years, whereas the wait-and-see approach had a risk of 1.9×10-6. Costs for early EMS vs. wait and see totaled approximately $142 million per life-year saved and exceeded $1.3 billion per death prevented, which researchers called excessive costs for minimal benefits.
Considerations
The authors cautioned that there is no universally accepted grading system for severe anaphylaxis. Through shared decision-making, the authors wrote, clinicians and patients would need to evaluate the applicability of risk factors for severe anaphylaxis including age, male sex, cardiac or pulmonary comorbidities and mastocytosis, among others. Patients with these factors should not consider self-management without consulting with their physician, the authors wrote.
Although they account for 3.92% of all anaphylaxis cases, biphasic anaphylaxis presents another risk, according to the authors. Associations include more severe initial presentation of anaphylaxis, the need for more than one dose of epinephrine to treat initial symptoms, wide pulse pressure, an unknown anaphylaxis trigger, dermatologic signs and symptoms, a drug allergen in children and delayed epinephrine treatment.
The side effects of epinephrine present concerns as well, the authors wrote, including elevations in heart rate and blood pressure, arrhythmias and angina. However, these side effects are extremely rare at the doses used in epinephrine auto-injection, and these risks are outweighed by the benefits of halting severe anaphylactic reactions.
With nearly all cases responding to less than two doses of epinephrine, very rare fatalities, the actual impact of EMS and ED care on cases and the costs of EMS and ED treatment, the authors concluded that at-home care would be more effective and less costly in many cases.
Still, the authors urged careful selection and education of these patients following shared decision-making, with appropriate access to medication and assistance when needed, as well as additional research into risk factors for future anaphylaxis.
For more information:
John J. Oppenheimer, MD, can be reached at nallopp22@gmail.com.
Perspective
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Aikaterini (Katherine) Anagnostou, MD (Hons), MSc, PhD
The authors suggest that it is time to reconsider the “used and taught” approach of activating EMS each time epinephrine is used to treat anaphylaxis, and they provide some valid arguments to support their recommendations. They propose the use of an at-home management algorithm in combination with shared decision-making, with the aim to decrease the number of ED visits and improve anaphylaxis outcomes.
I agree with the authors that current recommendations should be revised for many reasons, including the fact that most episodes of anaphylaxis respond to a maximum of two epinephrine doses, biphasic reactions are uncommon and fatalities are rare. Additionally, there is a lack of evidence that activation of EMS and an ED visit significantly improve outcomes.
Patients who are comfortable with managing anaphylaxis without activating an emergency response, have immediate access to two autoinjectors, know when and how to use them, have someone immediately available to help if symptoms worsen and have no risk factors for severe anaphylaxis or biphasic reactions may consider the proposed algorithm. However, it is important to remember that each patient is different, and a personalized approach is key. Patient preferences and values need to be accounted for before any decision is made.
A pilot study on the use of the at-home algorithm in carefully selected patients would be a useful first step to evaluate the proposed approach. If proven successful, it would have the potential to change the current landscape of anaphylaxis management, improve patient outcomes, bring significant cost savings to individuals and reduce the number of ED visits. In certain time periods, such as the recent pandemic, a decrease in the number of patients seeking help in the ED could also benefit society in general.
Before the proposed approach becomes standard practice, I would like to see more research on anaphylaxis outcomes with and without the activation of EMS, as well as on risk factors for severe anaphylaxis and biphasic reactions, as current recommendations are based on low certainty of evidence.
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