Emergency Department Management of Acute Asthma Exacerbations

Table of Contents

 

About This Issue

For an ED patient presenting with the wheezing, dyspnea, coughing, and chest tightness of an acute asthma exacerbation, the standard therapies of oxygen, short-acting beta agonists, anticholinergics, and systemic corticosteroids have been refined and supplemented in recent years. This issue reviews the latest evidence on managing patients with asthma emergencies, including:

Recognizing bronchospasm as a feature of other pathologies: heart failure, pneumonia, pulmonary embolism, and pneumothorax.

The key features of mild, moderate, and severe exacerbation, and how management and disposition will depend on the classification.

When to order point-of-care ultrasound for a patient with undifferentiated dyspnea and the findings that can reveal the diagnosis.

Blood gas, peak expiratory flow, ETCO₂, radiographs, FeNO: when these assessments can be useful.

The latest information on additional drug therapies for exacerbations, including magnesium sulfate, epinephrine, terbutaline, and ketamine, as well as novel biologics.

Trialing noninvasive positive-pressure ventilation, and strategies for intubation in severe cases.

Incorporating patient education and instruction to improve chronic asthma management and keep patients out of the ED.

1. About This Issue
2. Abstract
3. Case Presentations
4. Introduction
5. Critical Appraisal of the Literature
6. Epidemiology
   1. Prevalence of Asthma and Healthcare Costs
   2. Social Determinants and Risk Factors
7. Etiology and Pathophysiology
8. Differential Diagnosis
   1. Congestive Heart Failure
   2. Chronic Obstructive Pulmonary Disease
   3. Pneumonia/COVID-19
   4. Pulmonary Embolism
   5. Other Conditions in the Differential for Asthma
9. Prehospital Care
10. Emergency Department Evaluation
    1. History
    2. Physical Examination
       1. Classifications of Asthma Exacerbation
          • Mild Exacerbation
          • Moderate Exacerbation
          • Severe Exacerbation
11. Diagnostic Studies
    1. Laboratory Evaluation
    2. Point-of-Care Ultrasound
    3. Blood Gas
    4. Peak Expiratory Flow
    5. End-Tidal CO2 Monitoring
    6. Chest Radiographs
12. Treatment
    1. Oxygen
    2. Pharmacologic Agents
       1. Beta Agonists
          • Metered-Dose Inhalers Versus Nebulizers
          • Intermittent Versus Continuous Nebulizer Treatments
       2. Anticholinergics
       3. Corticosteroids
       4. Magnesium Sulfate
       5. Epinephrine
       6. Terbutaline
       7. Ketamine
    3. Noninvasive Positive Pressure Ventilation
    4. Intubation and Mechanical Ventilation
13. Special Populations
    1. Pediatric Patients
    2. Pregnant Patients
    3. Asthma Patients With COVID-19
14. Controversies and Cutting Edge
    1. Biologics
    2. Fractional Exhaled Nitric Oxide
    3. Heliox
    4. High-Flow Nasal Cannula
    5. Delayed Sequence Intubation
    6. Extracorporeal Membrane Oxygenation
15. Disposition
16. Time- and Cost-Effective Strategies
17. Risk Management Pitfalls for Asthma Exacerbations in the Emergency Department
18. Summary
19. Case Conclusions
20. Acknowledgment
21. Clinical Pathway for Management of Asthma Exacerbations in the Emergency Department
22. Tables and Figures
23. References

Abstract

Asthma is a disease of the airways characterized by inflammation, hyperresponsiveness, and bronchoconstriction. The diagnosis is primarily a clinical one, based on a focused history and physical examination, to differentiate from other entities such as heart failure, pneumonia, and pulmonary embolism. Radiographs, laboratory studies, and blood gases are not routinely recommended, except in atypical or refractory cases, or if there is diagnostic uncertainty. The cornerstone of acute asthma treatment includes short-acting beta agonists, anticholinergics, and systemic corticosteroids. This issue reviews the latest evidence in diagnostic and treatment strategies, including other pharmacologic treatments and newer management strategies to avoid intubation.

Case Presentations

A 43-year-old man with a history of frequent visits for asthma, including multiple admissions and intubations, is brought into the ED…

• The patient is anxious, tachypneic, using accessory muscles to breathe, and is in severe respiratory distress. On auscultation, air entry is significantly diminished, and he has faint expiratory wheezing.
• His blood pressure is 155/85 mm Hg; heart rate, 128 beats/min; respiratory rate, 30 breaths/min; temperature, 36.9°C; and oxygen saturation, 91% on 3 L nasal cannula.
• You place him on a cardiac monitor, begin treatment, and consider what other modalities can be used to avoid intubation…

A 22-year-old woman is brought in by EMS with complaints of difficulty breathing and dry cough. She is 20 weeks’ pregnant, with a history of several past hospital admissions for asthma…

• The patient says she discontinued her asthma medications because she said she did not want to harm the fetus.
• Her blood pressure is 120/75 mm Hg; heart rate, 115 beats/min; respiratory rate, 25 breaths/min; and room-air pulse oximeter reads 92%. You can hear audible wheezing and notice mild retractions. She is speaking in partial sentences.
• You consider what interventions for asthma are safe in pregnancy...

A 50-year-old man with a history of asthma is brought in by EMS after experiencing wheezing and shortness of breath all day…

• En route to the hospital, the paramedics have given him IV corticosteroids, nebulizer treatments, and magnesium sulfate, but he is not improving clinically.
• The patient's blood pressure is 180/110 mm Hg; heart rate, 125 beats/min; respiratory rate, 35 breaths/min; and oxygen saturation, 88% on 100% oxygen via aerosol mask. His arterial blood gas shows a PaO₂ of 68 mm Hg, PCO₂ of 110 mm Hg, and a pH of 7.1. He is using accessory muscles to breathe, and is clearly wearing down.
• You make the decision to intubate him before he decompensates further, and you consider the challenges of managing a critical asthmatic patient on mechanical ventilation…

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Clinical Pathway for Management of Asthma Exacerbations in the Emergency Department

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Tables and Figures

 

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Key References

Following are the most informative references cited in this paper, as determined by the authors.

2. * National Asthma Education and Prevention Program, Third Expert Panel on the Diagnosis and Management of Asthma. National Asthma Education and Prevention Program, Third Expert Panel on the Diagnosis and Management of Asthma. Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD: National Heart, Lung, and Blood Institute; 2007. Accessed January 10, 2022. (Clinical guidelines) DOI: 10.1016/j.jaci.2007.09.029

3. * Global Initiative for Asthma. Global strategy for asthma management and prevention. Accessed January 10, 2022. (Clinical guidelines) DOI: 10.1183/09031936.00138707

17. * Padem N, Saltoun C. Classification of asthma. Allergy Asthma Proc. 2019;40(6):385-388. (Review article) DOI: 10.2500/aap.2019.40.4253

37. * Long B, Lentz S, Koyfman A, et al. Evaluation and management of the critically ill adult asthmatic in the emergency department setting. Am J Emerg Med. 2021;44:441-451. (Review article) DOI: 10.1016/j.ajem.2020.03.029

41. * Suau SJ, DeBlieux PMC. Management of acute exacerbation of asthma and chronic obstructive pulmonary disease in the emergency department. Emerg Med Clin North Am. 2016;34(1):15-37. (Review article) DOI: 10.1016/j.emc.2015.08.002

89. * Weingart SD. Managing initial mechanical ventilation in the emergency department. Ann Emerg Med. 2016;68(5):614-617. (Review article) DOI: 10.1016/j.annemergmed.2016.04.059

126. *Cloutier MM, Baptist AP, Blake KV, et al. 2020 focused updates to the asthma management guidelines: a report from the National Asthma Education and Prevention Program Coordinating Committee Expert Panel Working Group. J Allergy Clin Immunol. 2020;146(6):1217-1270. (Update to clinical guidelines) DOI: 10.1016/j.jaci.2020.10.003

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Keywords: asthma, exacerbation, wheezing, beta agonist, SABA, anticholinergic, magnesium, NIPPV, ventilation, ketamine, epinephrine, biologics, COPD, FeNO, metered-dose inhaler, corticosteroid, intubation

Points and Pearls Excerpt

• The differential diagnosis for dyspnea includes COPD, heart failure, pneumonia, pulmonary embolism, and pneumothorax. See Table 4 for a list of physical examination findings for each.
• The National Asthma Education and Prevention Program² classifies asthma exacerbations thus:
  • Mild: well-appearing, dyspnea with light activity, subtle wheezing; symptoms usually resolve with treatment at home.
  • Moderate: dyspnea inhibits activity, wheezing on exhalation, increased accessory muscle use, increased respiratory rate, tachycardia.
  • Severe: dyspnea at rest, inability to speak sentences, significant accessory muscle use, tachypnea, tachycardia, diaphoresis, agitation, and altered mental status. Wheezing may be loud. Absent wheezing indicates impending respiratory failure; intubation should not be delayed if it is deemed necessary.