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Emergency department diagnosis and treatment of anaphylaxis: a practice parameter

Contents lists available at Practice Parameter Emergency department diagnosis and treatment of anaphylaxis:a practice parameter Ronna L. Campbell, MD, PhD; James T.C. Li, MD, PhD; Richard A. Nicklas, MD; Annie T. Sadosty, MDMembers of the Joint Task Force: David Bernstein, MD; Joann Blessing-Moore, MD;David Khan, MD; David Lang, MD; Richard Nicklas, MD; John Oppenheimer, MD; Jay Portnoy, MD;Christopher Randolph, MD; Diane Schuller, MD; Sheldon Spector, MD; Stephen Tilles, MD;Dana Wallace, MDPractice Parameter Workgroup: Ronna L. Campbell, MD, PhD; James T.C. Li, MD, PhD; Annie T. Sadosty, MD This parameter was developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma and Immunology; the American Collegeof Allergy, Asthma and Immunology; and the Joint Council of Allergy, Asthma and Immunology.
Disclaimer: The American Academy of Allergy, Asthma and Immunology (AAAAI) and the American College of Allergy, Asthma and Immunology (ACAAI) have jointlyaccepted responsibility for establishing "Emergency Department Diagnosis and Treatment of Anaphylaxis." This is a complete and comprehensive document at the currenttime. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated theefforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation ofthese practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the ExecutiveOffices of the AAAAI, the ACAAI, and the Joint Council of Allergy, Asthma and Immunology. These parameters are not designed for use by pharmaceutical companies in drugpromotion.
Reprints: Joint Council of Allergy, Asthma and Immunology, 50 N Brockway Street, #3-3, Palatine, IL 60067.
Published practice parameters of the Joint Task Force on Practice Parameters for Allergy and Immunology are available online at and Disclosures: The Joint Task Force recognizes that experts in a field are likely to have interests that could come into conflict with development of a completely unbiased andobjective practice parameter. To take advantage of that expertise, a process has been developed to prevent potential conflicts from influencing the final document in anegative way. At the workgroup level, members who have a potential conflict of interest do not participate in discussions concerning topics related to the potential conflict,or if they do write a section on that topic, the workgroup completely rewrites it without their involvement to remove potential bias. In addition, the entire document isreviewed by the Joint Task Force and any apparent bias is removed at that level. The practice parameter is sent for review by invited reviewers and by anyone with aninterest in the topic by posting the document on the Web sites of the ACAAI and the AAAAI.
Contributors: The Joint Task Force has made a concerted effort to acknowledge all contributors to this parameter. If any contributors have been excluded inadvertently, theJoint Task Force will ensure that appropriate recognition of such contributions is made subsequently.
Workgroup Chairs, Ronna L. Campbell, MD, PhD; James T. Li, MD, PhD; Joint Task Force Liaison, Richard A. Nicklas, MD, Clinical Professor of Medicine, GeorgeWashington Medical Center, Washington, DC; Joint Task Force Members, David I. Bernstein, MD, Professor of Clinical Medicine and Environmental Health, Division ofAllergy/Immunology, University of Cincinnati College of Medicine, Cincinnati, Ohio; Joann Blessing-Moore, MD, Adjunct Professor of Medicine and Pediatrics, StanfordUniversity Medical Center, Department of Immunology, Palo Alto, California; David A. Khan, MD, Associate Professor of Internal Medicine, University of TexasSouthwestern Medical Center, Dallas, Texas; David M. Lang, MD, Head, Allergy/Immunology Section, Division of Medicine, Director, Allergy and Immunology FellowshipTraining Program, Cleveland Clinic Foundation, Cleveland, Ohio; Richard A. Nicklas, MD, Clinical Professor of Medicine, George Washington Medical Center, Washington,DC; John Oppenheimer, MD, Department of Internal Medicine, New Jersey Medical School, Pulmonary and Allergy Associates, Morristown, New Jersey; Jay M. Portnoy,MD, Chief, Section of Allergy, Asthma & Immunology, The Children's Mercy Hospital, Professor of Pediatrics, University of MissourieKansas City School of Medicine,Kansas City, Missouri; Christopher C. Randolph, MD, Clinical Professor of Pediatrics, Yale Affiliated Hospitals, Center for Allergy, Asthma, & Immunology, Waterbury,Connecticut; Diane E. Schuller, MD, Professor of Pediatrics, Pennsylvania State University Milton S. Hershey Medical College, Hershey, Pennsylvania; Sheldon L. Spector,MD, Clinical Professor of Medicine, UCLA School of Medicine, Los Angeles, California; Stephen A. Tilles, MD, Clinical Professor of Medicine, University of WashingtonSchool of Medicine, Redmond, Washington; Dana Wallace, MD, Assistant Clinical Professor of Medicine, Nova Southeastern University College of Osteopathic Medicine,Davie, Florida; Parameter Workgroup Member, Annie T. Sadosty, MD; Assigned Reviewers: Estelle Simons, MD, Winnepeg, Manitoba, Canada; Marcella Aquino, MD,Mineola, New York.
1081-1206/Ó 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 Classification of recommendations and evidence Recommendation rating scale Strong recommendation A strong recommendation means the benefits of the recommended Clinicians should follow a strong recommendation unless a clear approach clearly exceed the harms (or that the harms clearly and compelling rationale for an alternative approach is present.
exceed the benefits in the case of a strong negativerecommendation) and that the quality of the supporting evidenceis excellent (grade A or B)*. In some clearly identifiedcircumstances, strong recommendations may be made based onlesser evidence when high-quality evidence is impossible toobtain and the anticipated benefits strongly outweigh the harms.
A recommendation means the benefits exceed the harms (or that Clinicians also should generally follow a recommendation but the harms clearly exceed the benefits in the case of a negative should remain alert to new information and sensitive to patient recommendation), but the quality of evidence is not as strong (grade B or C).* In some clearly identified circumstances,recommendations may be made based on lesser evidence whenhigh-quality evidence is impossible to obtain and the anticipatedbenefits outweigh the harms.
An option means that the quality of evidence that exists is suspect Clinicians should be flexible in their decision making regarding (grade D)* or that well-done studies (grade A, B, or C)* show little appropriate practice, although they may set bounds on clear advantage to one approach vs another.
alternatives; patient preference should have a substantialinfluencing role.
No recommendation No recommendation means there is a lack of pertinent evidence Clinicians should feel little constraint in their decision making and (grade D)* and an unclear balance between benefits and harms.
be alert to new published evidence that clarifies the balance ofbenefit vs harm; patient preference should have a substantialinfluencing role.
Category of evidence Protocol for finding evidence Ia Evidence from meta-analysis of randomized controlled trials A search of the medical literature was performed for different Ib Evidence from at least 1 randomized controlled trial terms that were considered relevant to this practice parameter.
Literature searches were performed on PubMed and the Cochrane Database of Systematic Reviews. All reference types were included IIb Evidence from at least 1 other type of quasi-experimental study in the results. References identified as relevant were searched for III Evidence from nonexperimental descriptive studies, such as relevant references and those references also were searched for comparative studies relevant references. In addition, members of the workgroup were IV Evidence from expert committee reports or opinions or clinical asked for references that were missed by this initial search.
experience of respected authorities or both Strength of recommendation* A Directly based on category I evidence This practice parameter is a joint effort between emergency B Directly based on category II evidence or extrapolated recom- physicians, who are often on the front line in the management of mendation from category I evidence anaphylaxis, and allergists-immunologists, who have a vested in- C Directly based on category III evidence or extrapolated terest in how such patients are managed. As recognized by emer- recommendation from category I or II evidence gency physicians and allergists, the timely administration of D Directly based on category IV evidence or extrapolated epinephrine is essential to the effective treatment of anaphylaxis, recommendation from category I, II, or III evidence and such administration is dependent on correctly diagnosing LB Laboratory based anaphylaxis. In an emergency department (ED) setting, with the broad and often atypical presentation of anaphylaxis, failure torecognize anaphylaxis is a real possibility. Failure to recognize Emergency department diagnosis and management of anaphylaxis inherently leads to undertreatment with epinephrine.
anaphylaxis: a practice parameter Studies have shown that a large percentage of patients (57%) whopresent to the ED with anaphylaxis can be The Joint Task Force on Practice Parameters Moreover, even when correctly diagnosed, epinephrine, the The Joint Task Force on Practice Parameters is a 13-member task essential first line in the treatment of anaphylaxis, is frequently (up force consisting of 6 representatives assigned by the American to 80% of the time) not administIn addition, patients who Academy of Allergy, Asthma and Immunology; 6 by the American are treated in the ED for anaphylaxis, frequently do not receive a College of Allergy, Asthma and Immunology; and 1 by the Joint prescription for auto-injectable epinephrine and usually are not Council of Allergy and Immunology. This task force oversees the referred for allergy follow-up.
development of practice parameters; selects the workgroup The recommendations made in this document about the man- chair(s); and reviews drafts of the parameters for accuracy, prac- agement of anaphylaxis apply to anaphylaxis that occurs in an ED ticality, clarity, and broad utility of the recommendations for clin- setting. Some of these recommendations might be different if ical practice.
anaphylaxis occurs in an office setting.

R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 It is important to understand that there is no absolute contra- condition. Obtain a serum tryptase level to assist in this regard indication to administration of epinephrine in the setting of after effective treatment has been rendered. (Moderate anaphylaxis. It also is important to recognize that anaphylaxis can Recommendation; C Evidence) progress rapidly from mild manifestations involving 1 organ sys- Summary Statement 6: Determine whether the patient has risk tem to severe involvement of multiple organ systems.
factors for severe and potentially fatal anaphylaxis, such asdelayed administration of epinephrine, asthma, a history ofbiphasic reactions, or cardiovascular disease, and consider these Compilation of summary statements in the management and/or disposition of all patients with Summary Statement 1: Base the diagnosis of anaphylaxis on the anaphylaxis. (Moderate Recommendation; B Evidence) history and physical examination, using scenarios described by Summary Statement 7: Administer epinephrine intramuscularly the National Institutes of Allergy and Infectious Disease (NIAID) in the anterolateral thigh as initial treatment for acute anaphy- Panel (but recognizing that there is a broad spectrum of laxis immediately after the diagnosis of anaphylaxis is made. The anaphylaxis presentations that require clinical judgment. Do not first line of treatment for patients experiencing anaphylaxis is rely on signs of shock for the diagnosis of anaphylaxis. (Strong epinephrine. (Strong Recommendation; B Evidence) Recommendation; C Evidence) Summary Statement 8: If the patient is not responding to Summary Statement 2: Carefully and immediately triage and epinephrine injections, administer an intravenous (IV) infusion monitor patients with signs and symptoms of anaphylaxis in of epinephrine in a monitored setting. (Moderate Recommen- preparation for epinephrine administration. (Strong Recom- dation; C Evidence) mendation; C Evidence) Summary Statement 9: If IV access is not readily available in Summary Statement 3: In general, place patients in a supine patients experiencing anaphylaxis, obtain intraosseous (IO) ac- position to prevent or counteract potential circulatory collapse.
cess and administer epinephrine by this route. (Moderate Place pregnant patients on their left side. (Moderate Recom- Recommendation; D Evidence) mendation; C Evidence) Summary Statement 10: Prepare for airway management, Summary Statement 4: Administer oxygen to any patient including intubation if necessary, if there is any suggestion of exhibiting respiratory or cardiovascular symptoms or patients airway edema (eg, hoarseness or stridor) or associated respira- with decreased oxygen saturation and consider for all patients tory compromise. (Moderate Recommendation; C Evidence) experiencing anaphylaxis regardless of their respiratory status.
Summary Statement 11: For patients with circulatory collapse (Moderate Recommendation; D Evidence) from anaphylaxis, aggressively administer large volumes of IV or Summary Statement 5: Expeditiously consider conditions other IO normal saline through large-bore catheters. (Strong Recom- than anaphylaxis that might be responsible for the patient's mendation; B Evidence) Figure 1. Visual representation of the NIAID/FAAN criteria. Reprinted with permission from the Internal Journal of Emergency Medicine.
R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 Summary Statement 12: Administer additional vasopressors or have a history of severe reactions.Although most cases of glucagon (especially if the patient is receiving b-blockers) if anaphylaxis will include cutaneous manifestations, the absence of parenteral epinephrine and fluid resuscitation fail to restore skin manifestations does not exclude a diagnosis of anaphylaxis.
blood pressure. (Moderate Recommendation; B Evidence) Summary Statement 2: Carefully and immediately triage and Summary Statement 13: Administer an inhaled b-agonist if monitor patients with signs and symptoms of anaphylaxis in bronchospasm is a component of anaphylaxis. (Moderate preparation for epinephrine administration. (Strong Recom- Recommendation; B Evidence) mendation; D Evidence) Summary Statement 14: Consider extracorporeal membraneoxygenation in patients with anaphylaxis who are unresponsive Anaphylaxis can progress rapidly and become life threatening.
to traditional resuscitative efforts. (Moderate Recommendation; monitoring, is essential for patients who are experiencing Summary Statement 15: Do not routinely administer antihista- anaphylaxis. This should include blood pressure, continuous pulse mines or corticosteroids instead of epinephrine. There is no rate, pulse oximetry, and electrocardiographic monitoring. IV ac- substitute for epinephrine in the treatment of anaphylaxis.
cess should be obtained as soon as possible. These measures should Administration of H1 and/or H2 antihistamines and corticoste- be used to monitor response to therapy and direct subsequent roids should be considered adjunctive therapy. (Strong Recom- mendation; B Evidence)Summary Statement 16: Identify triggers of anaphylaxis and Summary Statement 3: In general, place patients in a supine consider obscure and less common triggers. (Moderate position to prevent or counteract potential circulatory collapse.
Recommendation; C Evidence) Place pregnant patients on their left side. (Moderate Recom- Summary Statement 17: Strongly consider observing patients mendation; C Evidence) who have experienced anaphylaxis for at least 4 to 8 hours andobserve patients with a history of risk factors for severe A case series on anaphylactic deaths has suggested an associa- anaphylaxis, such as asthma, previous biphasic reactions, or tion between upright posture and To counteract the cir- protracted anaphylaxis, for a longer period (Moderate Recom- culatory collapse of anaphylaxis, patients generally should be mendation; C Evidence) placed in a supine position. However, patients in respiratory Summary Statement 18: Prescribe auto-injectable epinephrine distress could benefit from being in a more upright position while for patients who have experienced an anaphylactic reaction and they are monitored carefully for any circulatory collapse. Although provide patients with an action plan instructing them on how Trendelenburg positioning has long been proposed to prevent or and when to administer epinephrine. (Strong Recommendation; counteract hypotension, there is no evidence to support Trende- lenburg positioning and it might even be counterproductiv Summary Statement 19: Instruct patients who have experienced Pregnant patients should be placed on their left side to prevent anaphylaxis when discharged from the ED to see an allergist- the gravid uterus from compressing the inferior vena cava and immunologist. (Moderate Recommendation; C Evidence) obstructing venous return to the heart. Gentle manual displace-ment of the uterus may be necessary. The patient should not sit orstand suddenly because of the possibility of cardiac arrest caused ED diagnosis and management of anaphylaxis: a practice by the empty inferior vena cava syndrome.
Summary Statement 4: Administer oxygen to any patient Summary Statement 1: Base the diagnosis of anaphylaxis on the exhibiting respiratory or cardiovascular symptoms or patients history and physical examination, using scenarios described by with decreased oxygen saturation and consider for all patients the NIAID Panel () but recognizing that there is a broad experiencing anaphylaxis regardless of their respiratory status.
spectrum of anaphylaxis presentations that require clinical (Moderate Recommendation; D Evidence) judgment. Do not rely on signs of shock for the diagnosis ofanaphylaxis. (Moderate Recommendation; C Evidence) Summary Statement 5: Expeditiously consider conditions otherthan anaphylaxis that might be responsible for the patient's Symptoms of anaphylaxis are usually sudden in onset and can condition. Obtain a serum tryptase level to assist in this regard progress in severity over minutes to hours. Typically, at least 2 organ after effective treatment has been rendered. (Moderate systems are involved, although only 1 organ system might be Recommendation; C Evidence) initially involved. There is a broad spectrum of anaphylaxis pre-sentations that require clinical judgment. Although no set of diag- The differential diagnosis of anaphylaxis is broad. In the study nostic criteria for anaphylaxis will provide 100% sensitivity and noted in summary statement 1, the negative predictive value of the specificity, the criteria developed by the NIAID Panel in 2004 have proposed NIAID criteria was 98%, but the positive predictive value been shown to aid in the diagnosis of anaphy(The ac- was only 69%, showing that a significant number of patients who curacy of these criteria were retrospectively evaluated in an ED meet the criteria might not have anaphylaxis. The physician cannot setting and found to have 97% sensitivity and 82% specificityThe rely on the presence of shock to make a diagnosis of anaphylaxis. It is negative predictive value was 98% and the positive predictive value important to consider other conditions that could be responsible for was 69%; the positive likelihood ratio was 5.48, with a negative the patient's presentation: (1) cardiogenic, distributive, obstructive, likelihood ratio of 0.04. Therefore, these criteria are useful but do or hypovolemic shock; (2) pre-syncope or syncope; (3) hereditary not replace clinical judgment. It is important for health care pro- angioedema or angioedema induced by an angiotensin-converting viders to recognize the variable presentation and progression of enzyme inhibitor; (4) vocal cord dysfunction; (5) flushing such as anaphylaxis.Recognizing milder anaphylaxis is important not occurs associated with metastatic carcinoma or vasoactive intestinal only in preventing progression of a specific event to a more serious peptide-producing tumor; (6) respiratory distress from asthma, outcome but in preventing recurrent episodes in the future.
pulmonary embolism, congestive heart failure, or other causes; (7) Although anaphylaxis can present as hypotension alone, it isolated skin reactions, such as those that can be seen with adverse frequently presents without hypotension. Studies of fatal and near- drug reactions; (8) mast cell disorders, as discussed below; and (9) fatal anaphylaxis have shown that most of these patients did not psychiatric disorders, such as panic attacks.
R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 Serum tryptase is a marker of mast cell degranulation and could management.Epinephrine was administered only before arrest be useful for confirming the diagnosis of anaphylaxis. Thus, the ED in 14% of patients, and overall, only 62% received physician should consider obtaining a tryptase level if appropriate Patients with anaphylaxis can present with symptoms not follow-up of the test result can be assured (eg, with the patient's meeting the criteria for anaphylaxis and yet require administration primary care physician or by an allergist who agrees to see the of epinephrine, such as a patient with a history of near-fatal patient in follow-up. Because serum tryptase levels are not rapidly anaphylaxis to peanut who inadvertently ingests peanut and available, management of a patient with possible anaphylaxis within minutes is experiencing urticaria and generalized flushing.
should never be based on serum tryptase levels alone. However, Delayed administration of epinephrine is associated with poor when the diagnosis of anaphylaxis is uncertain, a serum tryptase outcomes and mortality.It is important to recognize that there is level could aid at follow-up in the diagnosis of anaphylaxis in a a broad spectrum of anaphylaxis presentations that require clinical given patient. The sensitivity of serum tryptase in patients who judgment in any given patient. The management of a patient who present to the ED with acute allergic reactions is low (21% in 1 presents with symptoms of anaphylaxis 15 minutes after exposure study).Moreover, serum tryptase level is not elevated in most to the suspected trigger might be handled differently than the patients who develop anaphylaxis from However, a small patient who was exposed 2 hours previously. Because anaphylaxis study using serial measurements of tryptase 15 and 60 minutes can be self-limited, patients can present at a point when symptoms after a sting challenge found that an increase of at least 2.0 mg/L had have nearly resolved and might no longer require epinephrine for a sensitivity of 73% and specificity of Serum tryptase levels acute management. However, the patient who presents with acute typically begin to increase approximately 30 minutes after the symptoms of anaphylaxis should immediately receive epinephrine onset of the reaction, peak 1 to 2 hours after the onset of the re- even if the initial symptoms are not life threatening, because action, and remain elevated for up to at least 6 to 8 anaphylaxis can progress rapidly from mild symptoms to severelife-threatening symptoms.
Summary Statement 6: Determine whether the patient has risk The management of anaphylaxis also can depend on the setting factors for severe and potentially fatal anaphylaxis, such as in which symptoms of anaphylaxis develop. For example, the pa- delayed administration of epinephrine, asthma, a history of tient who presents to the ED with urticaria 2 hours after eating biphasic reactions, or cardiovascular disease, and consider them shrimp might not require an injection of epinephrine. In contrast, a in the management and/or disposition of all patients with patient known to be allergic to shrimp who presents with symp- anaphylaxis. (Moderate Recommendation; B Evidence) toms consistent with upper airway obstruction 2 hours after eatingshrimp should receive an injection of epinephrine. The recom- Patients at risk of severe anaphylaxis include those with (1) mended dosage of epinephrine in a setting where an exact does can peanut and tree nut allergy, especially adolescents; (2) pre-existing be drawn up is 0.01 mg/kg (maximum dose, 0.5 mg) administered respiratory or cardiovascular disease; (3) asthma; (4) delayed intramuscularly every 5 to 15 minutes as necessary to control administration of epinephrine; (5) previous biphasic anaphylactic symptoms. The 5-minute interval between injections can be liber- reactions; (6) advanced age; and (7) mast cell alized to permit more frequent injections as determined by the Studies of fatal and near-fatal anaphylaxis have identified important risk factors for fatal anaphylaxis. Based on a national There are no randomized controlled studies of epinephrine registry, several risk factors for fatal anaphylaxis from foods have during anaphylaxis, including pharmacokinetic studies. A phar- been identifiMost patients have been shown to be adolescents macokinetic study in children not experiencing anaphylaxis or young adults, most have been allergic to peanuts or tree nuts, showed that epinephrine administered intramuscularly into the most have had a history of asthma, and very few have had anterolateral thigh resulted in a higher and more rapid peak plasma epinephrine administered in a timely mannerCauses of fatal concentration compared with subcutaneous administration in the anaphylaxis are presented in arm.A subsequent study in adults not experiencing anaphylaxis Summary Statement 7: Administer epinephrine intramuscularly showed that peak plasma epinephrine concentrations were higher in the anterolateral thigh as initial treatment for acute anaphy- and achieved faster after administration of epinephrine intramus- laxis immediately after the diagnosis of anaphylaxis is made. The cularly in the thigh compared with when it was administered first line of treatment for patients experiencing anaphylaxis is intramuscularly or subcutaneously in the Subcutaneous epinephrine. (Strong Recommendation; B Evidence) administration in the thigh has not been studied.
The physiologic effects of epinephrine include vasoconstriction, The decision to initiate specific treatment for anaphylaxis re- cardiac chronotropic and inotropic effects, bronchodilatation, and quires clinical judgment. However, when the patient is experiencing suppression of the release of histamine and other mediators form ongoing symptoms that are consistent with acute anaphylaxis, the mast cells and basophils, resulting in increased cardiac output, patient should receive epinephrine promptly. In a study of fatal food- increased peripheral vascular resistance, and decreased mucosal induced anaphylaxis in the United Kingdom, the median time to edema and airway resi respiratory or cardiac arrest was 30 minutes. The median time to Complications associated with parenteral administration of arrest in Hymenoptera venom-induced anaphylaxis has been shown epinephrine, other than IV administration, are very rare. There are to be 15 minutes and the median time to arrest in medication- no absolute contraindications for the administration of epinephrine induced anaphylaxis in a hospital setting has been shown to be 5 in the setting of anaphylaxis. Nevertheless, a significant percentage minutes, thus underscoring the need for rapid recognition and of patients treated for anaphylaxis do not receive Summary Statement 8: If the patient is not responding to epinephrine injections, administer an IV infusion of Causes of fatal anaphylaxis epinephrine in a monitored setting. (Moderate Recommenda- tion; C Evidence) If the patient is not responding to epinephrine injections, careful administration of an IV infusion of epinephrine in a monitored Abbreviation: RCM, radiocontrast media.
setting might be necessary. A 1:1,000,000 infusion solution,

R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 Figure 2. Emergency anaphylaxis management algorithm.
prepared by adding 1 mg (1 mL) of a 1:1,000 concentration of Endotracheal administration of epinephrine also can be epinephrine to 1000 mL of 5% dextrose in water or normal saline to considered in patients in whom IV access is not possible. Anec- produce a concentration of 1.0 mg/mL, can be infused at a rate of dotally, successful reports when using alternative routes have been 1 mg/min and titrated to the necessary hemodynamic response and reported. These include inhaled, sublingual, and endotracheal use in adults and adolescents increased to a maximum of 10.0 mg/min. A of epinephrine.
starting dose of 0.1 mg/kg per minute is recommended for children.
Bolus administration of IV epinephrine is associated with an Summary Statement 10: Prepare for airway management, increased risk of cardiac arrhythmias and inappropriate dosing and including intubation if necessary, if there is any suggestion of therefore should be avoided whenever In patients airway edema (eg, hoarseness or stridor) or associated respira- with actual or impending cardiovascular collapse unresponsive to tory compromise. (Moderate Recommendation; C Evidence) an epinephrine infusion or when an epinephrine infusion is notimmediately available, slow administration of a 50-mg (0.5 mL of Asphyxia can occur in anaphylaxis because of upper airway 1:10,000) bolus of IV epinephrine might be necessary.
swelling or brTherefore, it is necessary to prepare Summary Statement 9: If IV access is not readily available in for airway management, including intubation when necessary, if patients experiencing anaphylaxis, obtain IO access and there is any suggestion of airway edema (hoarseness or stridor) or administer epinephrine by this route. (Moderate Recommen- associated respiratory compromise. In severe cases of anaphylaxis, dation; D Evidence) airway management is an essential part of the treatment plan.
Whether to intubate the patient is a difficult decision. Airway Intraosseous fluid and medication administration is rapid, safe, management begins with preoxygenation, an assessment of the and effective.In animals, minimally delayed but equivalent level of predicted difficulty of laryngoscopy, and preparation.
hemodynamic effects have been seen with IO and IV administrations.
Various algorithms and scores have been designed to help predict Drug delivery appears to be slightly less when IO epinephrine is given difficult laryngoscopy, but their utility in the ED setting is limit in the tibia than when it is given in the sternum. Epinephrine can be Although a quick assessment of the airway should occur, given the infused by an IV or IO route at a rate of 1 mg/min and titrated to the significant potential for pharyngeal and laryngeal edema, laryn- necessary hemodynamic response, increasing to a maximum of 10.0 goscopy should be presumed to be difficult. Preparation includes mg/min for adults and adolescents. A starting dose of 0.1 mg/kg per selection and preparation of initial and back-up airway equipment minute is recommended for childr (including suction), optimizing patient positioning, pharmacology, R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 and the outlining of an initial and back-up airway management Epinephrine has been known for many years to effectively Upper airway edema can preclude rescue ventilation, so reverse bronchospasm. Sometimes, however, bronchospasm can the merits of an awake fiberoptic intubation should be strongly persist despite treatment with epinephrine. Therefore, current weighed against the benefits and risks of rapid sequence intubation.
approaches used to treat bronchospasm, such as b-adrenergic ag- When selecting airway management medications, because pa- onists, should be readily available if needed. There are no studies tients with anaphylaxis requiring intubation are often hemody- evaluating the effectiveness of b-adrenergic agonists in the treat- namically unstable, medications should be avoided that depress ment of bronchospasm occurring as part of anaphylaxis. However, blood pressure. Paralytics should be used with caution, because there is no reason to believe that the treatment of bronchospasm mask ventilation can be impossible in the setting of upper airway during anaphylaxis is different than the treatment of broncho- edema. Because the airway should be presumed difficult, optimizing spasm in patients who are not in anaphylaxis. This conclusion has the first look is essential no matter what approach is used. Once the been supported by observation of the effectiveness of inhaled b- patient is intubated, post-intubation management should continue adrenergic agonists in treating bronchospasm that occurs during with sedation and ventilator management. For the wheezing patient anaphylaxis. A b-agonist, such as albuterol, can be administered by with anaphylaxis, minimize breath stacking and barotraumas by a metered-dose inhaler (2e6 inhalations) or nebulizer (2.5e5 mg in allowing adequate exhalation time. In those with bronchospasm, 3 mL of saline and repeated as necessary) for bronchospasm that ketamine, a sedative with bronchodilator properties, can be used has not responded to epinephrine.
after intubation. Peri-intubation decompensation has a broad dif-ferential diagnosis. Because of the frequency of bronchospasm in Summary Statement 14: Consider extracorporeal membrane anaphylaxis, barotrauma should be considered.
oxygenation in patients with anaphylaxis who are unresponsive Nebulized epinephrine has been shown to alleviate respiratory to traditional resuscitative efforts. (Moderate Recommendation; distress associated with upper airway obstruction in childhood croupThe vasoconstrictive (a1) effects likely account for the Extracorporeal membrane oxygenation is becoming more readily decrease of upper airway edema. Similarly, and based on anecdotal available in the ED and can be applied to anyone with reversible experience, aerosolized epinephrine also can decrease oropharyngeal causes of pulmonary and/or cardiac failure. Patients with anaphylaxis edema and make airway management less difficult in anaphylaxis.
who are unresponsive to traditional resuscitative efforts should be Summary Statement 11: For patients with circulatory collapse considered candidates for this potentially life-saving therapy. There from anaphylaxis, aggressively administer large volumes of IV or are several case reports of successful resuscitation of refractory IO normal saline through large-bore catheters. (Strong Recom- anaphylaxis involving extracorporeal membrane oxygenation or mendation; B Evidence) operative cardiopulmonary bypass.The decision to initiateextracorporeal membrane oxygenation can be difficult but should be Aggressive fluid resuscitation helps to counteract the significant considered early in patients who are failing to respond to traditional plasma leak associated with anaphylaxis and complement parenteral resuscitative measures and before irreversible ischemic acidosis epinephrine therapy. Children might require successive IV fluid boluses of 20 mL/kg and adults might require successive IV boluses of1,000 mL to maintain blood pressure in the early stages of anaphylaxis.
Summary Statement 15: Do not routinely administer antihista- To overcome venous resistance, fluids administered through IO cath- mines or corticosteroids instead of epinephrine. There is no eters should be infused under pressure using an infusion pump, pres- substitute for epinephrine in the treatment of anaphylaxis.
sure bag, or manual pressure. As blood pressure stabilizes, fluid rates Administration of H1 and/or H2 antihistamines and corticoste- should be adjusted. Care should be taken to avoid volume overload in roids should be considered adjunctive therapy. (Strong Recom- certain patients, such as those with a history of left ventricular failure.
mendation; B Evidence) Summary Statement 12: Administer glucagon (especially if the Use of antihistamines in anaphylaxis is believed justified based patient is receiving b-blockers) if parenteral epinephrine and on their mechanism of action and effectiveness in other allergic uid resuscitation fail to restore blood pressure. (Moderate diseases, such as allergic rhinitis and allergic conjunctivitis. Many Recommendation; B Evidence) clinical manifestations of anaphylaxis, including vasodilatation,increased Norepinephrine, vasopressin, and other pressors have been used contraction, and increased airway secretions, are mediated by with success in patients in anaphylaxis with refractory hypotension histamine. However, there is no direct evidence to show that an- (see Infusions of glucagon have been used to treat tihistamines are effective in anaphyIn fact, their onset of anaphylaxis that is refractory to epinephrine in some patients on b- action is not rapid enough to be useful in the acute management of blockers.There are numerous case reports of treatment refractory anaphylaxis. Therefore, epinephrine administration should not be anaphylaxis in patients on b-blockers.There also are case re- delayed in patients with anaphylaxis while the patient is observed ports of such patients responding favorably to glucagon infusion for a response to antihistamines. Antihistamines are never a sub- when standard therapy has failed. Glucagon increases cyclic aden- stitute for epinephrine in the treatment of anaphylaxis. The rec- osine monophosphate intracellularly, independent of adrenergic ommended dose for diphenhydramine, an H receptors, and might reverse refractory hypotension and broncho- intramuscular or by slow IV infusion is 25 to 50 mg in adults and 1 spasm.Although data are very limited, glucagon infusion should to 50 mg/kg 50 mg in children. Oral diphenhydramine and other be considered when patients are not responding to traditional oral first- or second-generation H management. The recommended dose of glucagon is 1 to 5 mg 1 antihistamines also can be used.
2 antihistamines, such as cimetidine, at an IV dose of 4 mg/kg, are e30 mg/kg [maximum, 1 mg] in children) administered intrave- used widely in anaphylaxis treatment. They are recommended as nously over 5 minutes and followed by an infusion of 5 to 15 mg/min second-line medications in the treatment of anaphylaxis in most titrated to clinical response. Airway protection is important because guidelines and other well-known references.
emesis and possible aspiration is a possible side effect of glucagon.
Corticosteroids also have a slow onset of action (4e6 hours) and Summary Statement 13: Administer an inhaled b-agonist if therefore, like antihistamines, are not effective in the acute man- bronchospasm is a component of anaphylaxis. (Moderate agement of anaphylaxis. There is no strong evidence that supports Recommendation; B Evidence) the use of corticosteroids in the management of anaphylaxis.
R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 Moreover, there no definitive evidence to indicate that corticoste- longer periods of observation should be considered for patients roids decrease the risk of biphasic reactions, although there is a who have a history of risk factors for more severe anaph theoretical possibility, owing to their anti-inflammatory properties, Longer periods of observation should be considered in patients that they could decrease such reactDosing of corticosteroids who ingested the allergen, required more than 1 dose of should be 1.0 to 2.0 mg/kg per dose of methylprednisolone or an epinephrine, had hypotension or pharyngeal edema, or have a equivalent formulation. Oral doses of prednisone also can be history of asthma.
considered (1.0 mg/kg, up to 50 mg).
Patients allowed to leave the ED after complete resolution of Summary Statement 18: Prescribe auto-injectable epinephrine symptoms of anaphylaxis do not routinely need further treatment for patients who have experienced an anaphylactic reaction and with antihistamines or corticosteroids. There are no studies that provide patients with an action plan instructing them on how have evaluated the benefits of these medications after patients and when to administer epinephrine. (Moderate Recommen- leave the ED if their symptoms of anaphylaxis have resolved before dation; C Evidence) they leave the ED.
After leaving the ED, patients are at risk for reencountering the Summary Statement 16: Identify triggers of anaphylaxis and allergen that triggered the anaphylactic reaction treated in the ED.
consider obscure and less common triggers. (Moderate As noted under summary statement 16, biphasic reactions can Recommendation; C Evidence) occur in up to 20% of patients who present with an anaphylacticreaction. Therefore, patients need to be prepared for possible There are a myriad of triggers of anaphylaxis. The frequency of recurrent anaphylaxis and should be given 2 auto-injectable specific triggers can vary with age.In pediatric patients, the epinephrine devices to carry with them at all times. Children most common cause of anaphylaxis is food ingestion; in adults, the weighing 15 to 30 kg can receive a 0.15-mg dose of epinephrine cause of anaphylaxis is not identified approximately 25% of the from an auto-injector. Children weighing more than 30 kg and time.In older adults, medications are the most common cause of adults can receive a 0.3-mg dose of epinephrine from an auto- anaphylaxis, with antibiotics and nonsteroidal anti-inflammatory injector. Recognize that 0.01 mg/kg, the recommended dose, drugs topping the list of The most common cannot be exactly administered using the available auto-injector cause of drug-induced anaphylaxis is b-lactam antibiotics, although doses, so some judgment is required.
recently there has been an increasing number of reports of Studies have shown that up to 30% of patients who develop anaphylaxis or anaphylactoid reactions from biological mod- anaphylaxis will have to administer more than 1 dose of epineph- ifiers.Exercise, latex, and seminal fluid are other causes of rine.A large percentage of patients use epinephrine injectors anaphylaxis that need to be considered, as do non-IgEemediated incorrectly and inadvertent injection of epinephrine into the digits reactions such as to radiocontrast media.
has increased significantly in the past decade.Therefore, it is Overall, foods, drugs, and stinging insect venom are the most essential that health care providers demonstrate for patients the common causes of anaphylaxis. However, the actual food compo- proper use of an epinephrine auto-injector and confirm patient nent causing anaphylaxis might not be readily apparent, resulting proficiency. Parents of food-allergic children were 4 to 5 times more in the exact cause of anaphylaxis being missed. In 1 study, 47% of likely to effectively administer self-injectable epinephrine after a patients with food allergy were not diagnosed with food allergy in practical demonstrPatients and caregivers should be the Less apparent triggers of anaphylaxis also should be instructed to administer epinephrine at the first sign of a general- considered (eg, galactose and a1,3 galactose, a carbohydrate found ized reaction or if the patient develops any manifestations that in mammalian meat), particularly in patients who present with have preceded the development of anaphylaxis. The allergist- delayed anaphylaxis. The allergist-immunologist should play an immunologist can play an important role in this educational pro- important role in identifying less readily apparent causes of cess during follow-up.
anaphylaxis at follow-up.
Summary Statement 17: Strongly consider observing patients Summary Statement 19: Instruct patients who have experienced who have experienced anaphylaxis for at least 4 to 8 hours and anaphylaxis when discharged from the ED to see an allergist- observe patients with a history of risk factors for severe immunologist in a timely fashion. (Moderate Recommenda- anaphylaxis (eg, asthma, previous biphasic reactions, or pro- tion; C Evidence) tracted anaphylaxis) for a longer period. (Moderate Recom-mendation; C Evidence) The cause of anaphylaxis is frequently unknown at the time of discharge from the ED or at the time of admission to the hospital Admission rates for anaphylaxis vary widely from 7% to 4 (see Preface). Therefore, follow-up with a physician with expertise being somewhat lower in pediatric patients.The decision to in the diagnosis and management of anaphylaxis, such as an admit should be based on symptom severity, response to treat- allergist-immunologist, is extremely important.
ment, pattern of previous anaphylactic reactions (eg, a history of Anaphylaxis might be the presentation of a mast cell disorder. In protracted or biphasic reactions), medical comorbidities, patient a study of patients with a history of anaphylaxis after an insect reliability, and access to medical care. If the patient is not being sting, approximately 8% were found to have an underlying mast cell admitted to the hospital, a period of observation should be strongly Mast cell disorders are diverse and can have multiple considered in all patients diagnosed with anaphylaxis. Biphasic manifestations and complications affecting essentially every organ reactions occur in up to 20% of patients who develop anaphylaxis system and ranging in severity from indolent cutaneous disorders and could involve organ systems not affected in the initial reac- to rapidly fatal leukemia.
There is no evidence that systemic corticosteroids will Allergists-immunologists can obtain a detailed history, coordi- prevent biphasic reactions. Moreover, as serum epinephrine levels nate additional outpatient testing, provide additional allergen- wane, symptoms can recurExpert consensus opinion has rec- avoidance counseling, develop a detailed emergency action ommended that patients be observed for 4 to 8 hours. However, the plan for future reactions, provide the patient with medical identi- time of observation should be individualized based on the same fication jewelry, and reinforce the proper use of auto-injectable criteria used to determine the need for admission. In addition, R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608 R.L. Campbell et al. / Ann Allergy Asthma Immunol 113 (2014) 599e608

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