You have a new patient!
A 40-year-old female with a known case of asthma presents to the emergency department (ED) with complaints of cough, difficulty breathing, chest tightness, and audible wheezing. She has had fever and flu symptoms for three days, which she believes she caught from a colleague at work. She has taken her prescribed home medications with no relief. Her symptoms got worse over the last 2 hours. Her vitals were BP 140/90 mmHg, HR 122 bpm, RR 42 bpm, and SpO2 92% on room air. The physical exam revealed the use of accessory muscles for respiration, expiratory wheezing, and decreased breath sounds with expiratory rhonchi bilaterally.
Nebulized short-acting beta2-agonists (SABA) and systemic corticosteroids were ordered. Peak expiratory flow (PEF) measurements before and after treatment were 125 and 360, respectively. Auscultation after initial treatment revealed much-improved airflow. The patient was discharged following clinical improvement, with a prescription of oral corticosteroids in addition to her current medications.
What do you need to know?
Importance
Asthma is characterized by recurrent symptoms of reversible airway obstruction that range in severity, including bronchial hypersensitivity, hyperresponsiveness, bronchospasm, inflammation, and bronchial hypersensitivity [1,2]. While the exact causes of asthma, a complex chronic disease of the airways, are still not fully understood, researchers continue to study the condition. The high cost of managing and treating asthma is a barrier to effective asthma management. Lack of access, non-compliance with asthma treatment, and excessive reliance on emergency rooms significantly impact asthma morbidity and mortality [1].
Epidemiology
The prevalence of asthma is higher in children than in adults, in women than in men, and in Puerto Ricans and African Americans than in whites or other Hispanics. Adults aged 65 and older have been reported to have the highest death rates, while children 0 to 4 years old have the lowest rates. Asthma deaths were 1.3 times more common in women than in men. The mortality rate from asthma was 2.5–3 times higher among African Americans than among whites [1].
Pathophysiology
Asthma can be divided into allergic and non-allergic based on the presence or absence of immunoglobulin E (IgE) antibodies to common environmental antigens (pollen, dander, mites) and microbiologic antigens (bacteria, viruses). The presence of airway T-helper cells, which release cytokines like interleukin [IL]-4, IL-5, and IL-13 to promote basophil, eosinophil, mast cell, and leukocyte migration to the airways and increase IgE production, is a characteristic of all types of asthma. The outcome is an exacerbation of the inflammatory response in the airways and, over time, irreversible remodeling of the airways. Clinical manifestations of these intricate cellular interactions include bronchospasm, mucus production, airway edema, and airflow restriction [1].
Medical History
Initial history inquiries should include potential triggers, symptom onset, and severity, particularly compared to prior exacerbations. Physicians should also identify comorbidities, particularly those that might be worsened by systemic corticosteroids, like diabetes, peptic ulcer disease, hypertension, and psychosis. All current asthma medications and the times and dosages taken recently should be highlighted. Moreover, any potential asthma aggravators, such as aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs), beta-blockers (including topical agents used for glaucoma), and angiotensin-converting enzyme inhibitors, should also be noted. The use of beta-blockers, both cardioselective and nonselective, increases emergency room visits and hospitalizations. There is a variance in dyspnoea perception among asthmatics with the same degree of airway narrowing. Patients with poor perceptions of their dyspnoea are more likely to require emergency room visits and hospital stays and experience near-fatal and fatal asthma attacks [1].
Physical Examination
Asthma is characterized by classical symptoms such as cough, shortness of breath, and wheezing. Additional clinical features often observed in asthma patients include tachypnea, tachycardia, chest tightness, and cyanosis. In more severe cases, patients may present with the use of accessory muscles for breathing, a “silent chest” (indicative of minimal airflow), altered level of consciousness, or even collapse, highlighting the potential severity of this respiratory condition.
The physical examination findings and some bedside test results for asthma patients vary depending on the severity of the acute asthma attack [3].
For moderate asthma, patients may exhibit increasing symptoms with a peak expiratory flow (PEF) of 50–75% of the predicted value, but they show no physical signs of acute severe asthma.
In acute severe asthma, physical examination may reveal a PEF of 33–50% of the predicted value, a respiratory rate ≥25 breaths per minute, a heart rate ≥110 beats per minute, and an inability to complete sentences in one breath due to shortness of breath.
For life-threatening asthma, physical findings can include altered consciousness, exhaustion, cyanosis (bluish discoloration of the skin), a silent chest (indicative of critically reduced airflow), arrhythmias, and hypotension. Measurements include a PEF of less than 33% of the predicted value, oxygen saturation (SpO₂) below 92%, and normal arterial partial pressure of carbon dioxide (PaCO₂) between 4.6–6.0 kPa, despite the severity of the attack.
In the case of near-fatal asthma, the physical exam may demonstrate poor respiratory effort, and the condition is characterized by elevated PaCO₂ levels or the need for mechanical ventilation with raised inflation pressures, reflecting a critically severe respiratory compromise.
These findings collectively aid in categorizing the severity of asthma attacks and guiding appropriate management.
Alternative Diagnoses
When treating acutely breathless patients, it is imperative to consider aetiologies other than asthma. The differential diagnoses include pneumonia, COPD exacerbation, upper airway obstruction, foreign body aspiration, pulmonary embolism, congestive heart failure, allergic anaphylactic reaction, and gastroesophageal reflux disease. Any of these diagnoses can present concurrently with asthma [1,3].
Acing Diagnostic Testing
In the evaluation and management of acute asthma exacerbations, several diagnostic tools can aid in assessing the severity of the condition and guiding treatment decisions:
Peak Expiratory Flow Rate (PEFR)
Peak Expiratory Flow Rate (PEFR) should be measured in all asthma patients presenting with acute exacerbations as it provides an objective assessment of airway obstruction severity. If a patient is unable to perform the PEFR test, this inability is a critical indicator of severe airway obstruction and necessitates urgent management. PEFR is most valuable when compared to the patient’s previous personal best measurement, as it reflects their baseline respiratory function. In cases where the personal best measurement is unavailable, the predicted PEFR percentage, calculated based on the patient’s age, sex, and height, serves as a practical alternative to estimate the severity of the airway obstruction. Regular monitoring of PEFR can assist in early detection of exacerbations and guide treatment adjustments.
Pulse Oximetry
This non-invasive method is crucial for determining the effectiveness of oxygen supplementation, especially in children or other patients unable to perform PEFR. The target SpO₂ is 94%-98%, with levels below 90% signaling the need for more aggressive therapy.
Capnography
Capnography is valuable for monitoring hypercapnia and respiratory failure in asthma patients. Waveform capnography provides continuous monitoring, showing changes in airway diameter and improvements during acute asthma management.
Blood Gas Analysis
Routine arterial blood gas (ABG) analysis is not typically indicated in acute asthma exacerbations. However, ABG testing should be considered when SpO₂ is below 92% or when PEFR is less than 50% of the patient’s personal best or predicted value, to identify hypercapnia and guide critical care.
Other blood testing
Routine blood testing is not recommended for acute asthma exacerbations. However, in older patients with cardiovascular comorbidities, B-type natriuretic peptide (BNP) levels may be useful to detect unrecognized congestive heart failure.
A chest radiograph (CXR)
Although not routinely required, a chest X-ray may be warranted in cases of suspected complications such as pneumonia, pneumothorax, pneumomediastinum, subcutaneous emphysema, or congestive heart failure.
Electrocardiogram (ECG)
ECG is helpful for assessing patients with chest pain or cardiovascular disease, where the asthma exacerbation may act as a physiologic stressor. In severe asthma, ECG may show a reversible right ventricular strain pattern. Continuous cardiac monitoring is advised for patients with severe hypoxemia.
Point of care ultrasound (POCUS)
Increasingly used in emergency settings, POCUS aids in diagnosing complications like pneumothorax and heart failure in patients with acute dyspnea, offering rapid, bedside insights [4].
Risk Stratification
There are several risk stratification tools for asthma, particularly for the pediatric population. MDCalc offers various tools to evaluate asthma severity and predict future exacerbations. One such tool is the PEFR (Peak Expiratory Flow Rate) estimator, which provides expected PEFR values based on the patient’s age, height, and ethnicity. Additionally, this tool allows clinicians to input the patient’s measured PEFR and offers management suggestions tailored to the patient’s condition. These tools, among others, can assist physicians in managing asthma patients more effectively.
However, in time-sensitive situations, there may not be enough time to use such tools, requiring immediate recognition of risk factors for death from asthma [1,5], which include:
- History of sudden severe exacerbations
- Prior intubation for asthma
- Prior asthma admission to an intensive care unit (ICU)
- Two or more hospitalizations for asthma in the past year
- Three or more emergency department (ED) care visits for asthma in the past year
- Hospitalization or an ED care visit for asthma within the past month
- Use of more than two MDI short-acting beta-2 agonist canisters per month
- Current use of or recent withdrawal from systemic corticosteroids
- Difficulty perceiving severity of airflow obstruction.
- Comorbidities such as cardiovascular diseases or other systemic problems
- Serious psychiatric disease or psychosocial problems
- Illicit drug use, especially inhaled cocaine, and heroin
Management
Effective management of acute asthma exacerbations involves a combination of pharmacological and non-pharmacological interventions tailored to the severity of the patient’s condition. Below is a detailed explanation of these management strategies:
Oxygen Therapy
Oxygen supplementation should be provided to all hypoxemic patients to maintain oxygen saturation (SpO₂) within the target range of 94%-98%. Adequate oxygenation is critical for preventing further respiratory compromise.
Beta-2 Agonist Bronchodilators
Short-acting beta-2 agonists, such as albuterol, are first-line agents for treating acute asthma attacks and should be initiated promptly. Albuterol can be administered via nebulization at a dose of 2.5–5 mg or with a metered-dose inhaler (MDI) delivering 6–12 puffs. The use of an MDI with a spacer provides comparable benefits to nebulization in both adults and children in emergency settings [6]. For patients who cannot use inhaled therapy effectively, intravenous (IV) or subcutaneous beta-2 agonists may be considered, although evidence supporting their use in ventilated or critically ill patients remains limited.
Anticholinergic Agents
Anticholinergic medications, such as ipratropium, are less potent than beta-2 agonists and have a slower onset of action, so they should not be used alone for acute attacks. However, combining a short-acting beta-agonist (SABA) with ipratropium is particularly beneficial in moderate to severe exacerbations, reducing hospitalizations and improving peak expiratory flow rates (PEFR). The initial adult dose of ipratropium is 250–500 mcg.
Corticosteroids
Corticosteroids are essential in the early management of acute asthma exacerbations. Both oral and intravenous (IV) corticosteroids are equally effective, with no additional benefit from adding inhaled corticosteroids to systemic therapy. The recommended oral dose is 50 mg of prednisone, while IV therapy typically involves 125 mg/day of methylprednisolone in one or two divided doses.
Magnesium
Magnesium sulfate is a bronchodilator that relaxes bronchial smooth muscles, making it particularly useful in severe asthma attacks. It is recommended for adults with PEFR <25% of the predicted value, adults and children with persistent hypoxia after initial treatment, and children with PEFR <60% after one hour of care. Magnesium has been shown to reduce hospital admission rates in these patients.
Epinephrine
For asthma patients with concurrent angioedema or anaphylaxis, epinephrine should be administered intramuscularly at a dose of 0.3 mg. This is an adjunct to standard asthma therapies.
Heliox (Helium-Oxygen Therapy)
Heliox reduces airway resistance and enhances the bronchodilatory effects of albuterol [7]. It also reduces respiratory muscle workload and improves ventilation by facilitating carbon dioxide diffusion. Heliox may be considered in severe airflow obstruction (PEFR <30% predicted), rapid onset of symptoms within 24 hours, a history of labile asthma or prior intubation, or in cases where mechanical ventilation is inadequate.
Ketamine
Ketamine, an IV dissociative agent with bronchodilatory properties, is a valuable adjunctive therapy in refractory status asthmaticus when standard treatments are insufficient [8].
High-Flow Nasal Cannula (HFNC)
HFNC delivers high concentrations of oxygen, reduces work of breathing, and provides continuous positive airway pressure. While its role in adults with asthma is not well-defined, small studies suggest it may alleviate respiratory distress in children.
Non-Invasive Ventilation (NIV)
NIV may benefit select patients with severe and resistant asthma. However, it is not a substitute for endotracheal intubation and mechanical ventilation when these are indicated.
Intubation and Mechanical Ventilation
Approximately 2% of all asthma exacerbations, and 10%-30% of cases requiring ICU admission, necessitate intubation. Indications for intubation include altered consciousness, coma, respiratory or cardiac arrest, paradoxical breathing patterns, refractory hypoxemia, and failure of NIV.
Extracorporeal Membrane Oxygenation (ECMO)
In patients with asthma refractory to conventional ventilator management, ECMO may be considered as a last resort to provide oxygenation and ventilation support.
These therapeutic approaches, used in a stepwise manner based on severity, help optimize outcomes for patients experiencing acute asthma exacerbations. Early intervention, combined with evidence-based management, remains critical in preventing complications and reducing mortality.
Special Patient Groups
Pediatrics
For pediatric patients, the recommended initial dose of albuterol is 0.15 mg/kg/dose (0.03 mL/kg/dose), with a maximum dose of 5 mg via nebulization. Alternatively, administering 4–12 puffs of a short-acting beta-agonist (SABA) via a metered-dose inhaler (MDI) with a spacer provides equivalent bronchodilation compared to nebulized therapy. The initial dose of ipratropium bromide depends on the child’s weight: 250 micrograms for children weighing less than 20 kg and 500 micrograms for those over 20 kg.
In terms of corticosteroids, dexamethasone is an effective alternative to prednisone for managing acute asthma in the emergency department, offering comparable efficacy with fewer doses, less vomiting, and improved compliance. For moderately to severely ill children, continuous nebulized albuterol, corticosteroids, magnesium sulfate, and parenteral SABAs form the cornerstone of management.
Admission to the Pediatric Intensive Care Unit (PICU) is indicated for children with continued severe respiratory distress, altered mental status, or the need for advanced interventions such as intravenous SABAs, non-invasive ventilation (e.g., BiPAP), or mechanical ventilation.
Geriatrics
In elderly patients, asthma symptoms may go unreported as they may attribute their shortness of breath to aging, obesity, or comorbid cardiovascular conditions. It is essential for physicians to inquire about all home medications, including eye drops, and carefully consider potential drug interactions to avoid complications.
Pregnancy and Breastfeeding
Asthma exacerbations during pregnancy should be treated in the same manner as in nonpregnant patients. There are no contraindications to using any asthma medication in breastfeeding patients, making treatment decisions more straightforward and ensuring both maternal and infant safety.
When To Admit This Patient
Relapse rates among asthmatic patients discharged from the emergency department (ED) vary significantly, ranging from 11% within 3 days to 45% at 8 weeks.
The Emergency Department Disposition Decision-Making Guidelines assist in determining the appropriate care site for asthmatic patients based on their peak expiratory flow (PEF) percentages and response to treatment [1]. Below are the key details for each category:
Good Response
- PEF (% predicted/personal best): Approximately 60% or higher.
- Disposition Site: Patients with a good response are typically discharged home. Hospitalization is not necessary.
Incomplete Response
- PEF (% predicted/personal best): Between 40% and 60%.
- Disposition Site: The decision to send patients home or hospitalize them depends on the presence of risk factors outlined in Box 1. A careful evaluation is required to decide the appropriate course of action.
Poor Response
- PEF (% predicted/personal best): Less than 40%.
- Disposition Site: Patients in this category are not discharged home and require continued therapy in the emergency department. Hospitalization is necessary if the facility is available and appropriate.
Additional Factors Increasing the Likelihood of Admission
- Female sex, older age, and non-white race.
- Use of more than 8 beta-agonist puffs in the past 24 hours.
- Severity of exacerbation, such as the need for rapid medical intervention upon arrival, respiratory rate >22, oxygen saturation <95%, and final PEF <50% predicted.
- Past history of intubations or asthma-related hospital admissions.
- Previous use of oral corticosteroids (OCS).
These guidelines ensure that patients receive care tailored to the severity of their asthma exacerbation and associated risk factors.
The risk factors for death from asthma can be categorized into asthma history and other factors [1]:
Asthma History:
- A history of near-fatal asthma that required intubation and mechanical ventilation.
- Hospitalization or emergency department (ED) visits for asthma in the past year.
- Current or recent use of oral corticosteroids, which is a marker of event severity.
- Not currently using inhaled corticosteroids.
- Overuse of short-acting beta-agonists (SABAs), particularly using more than one canister per month.
- Poor adherence to asthma medications or a lack of adherence to a written asthma action plan.
Other Factors:
- Presence of psychosocial problems.
- Psychiatric diseases.
- Food allergies in individuals with asthma.
Revisiting Your Patient
The patient in the case presentation is a 40-year-old female with known asthma. She presented with asthma exacerbation due to upper respiratory tract infection with sick contact at work. In the history, asking for any other potential triggers of an acute exacerbation, including potential allergen, onset of symptoms, and severity, is useful. Physical examination should focus on signs that help categorize the disease’s severity and guide a management plan. Like any other emergency, initial evaluation and management should highlight the “ABCDs” assessment (Airway, Breathing, Circulation, and Disability), along with imitation of the appropriate and time-sensitive diagnostic and therapeutic interventions (in our case, initiation of SABA and systemic steroids).
Additionally, Peak Expiratory Flow Rate (PEFR) should be performed for all asthmatics presenting with acute exacerbation who can perform the test. Patients who are unable to perform the test should be considered to have severe airway obstruction. If the patient is fit for discharge, prescription medications and appropriate follow-up appointments should be initiated, with strict return precautions to the emergency department as needed.
Authors
Mohamed Elamin Salama
Dr. Salama is currently a Specialty Registrar in Emergency Medicine at the Thames Valley Deanery, Oxford School of Emergency Medicine. He completed his emergency medicine training at Zayed Military Hospital and has obtained both the Arab and Emirati Board certifications in Emergency Medicine. Dr. Salama is dedicated to advancing his clinical practice and actively sharing the most current developments in medical knowledge. His professional interests encompass trauma, resuscitation, sports medicine, and the promotion of public health initiatives.
Ahmed Norain
Emergency Department, Zayed Military Hospital, Abu Dhabi
Listen to the chapter
References
- Walls RM, Hockberger RS, Gausche-Hill M, Erickson TB, Wilcox SR. Rosen’s Emergency Medicine: Concepts and Clinical Practice, 10th edition. Elsevier; 2023.
- Gary T Kitching, Jason B Lee. Asthma in Adults. RCEMLearning. Accessed March 8, 2023. https://www.rcemlearning.co.uk/reference/asthma-in-adults/#1568193285479-ef3b01a0-b2ab
- Global Initiative for Asthma. GLOBAL STRATEGY for ASTHMA MANAGEMENT and PREVENTION Updated 2022.; 2022. https://ginasthma.org/wp-content/uploads/2022/07/GINA-Main-Report-2022-FINAL-22-07-01-WMS.pdf
- Zanobetti M, Scorpiniti M, Gigli C, et al. Point-of-Care Ultrasonography for Evaluation of Acute Dyspnea in the ED. Chest. 2017;151(6):1295-1301. doi:10.1016/j.chest.2017.02.003
- D’Amato G, Vitale C, Molino A, et al. Asthma-related deaths. Multidiscip Respir Med. 2016;11:37. Published 2016 Oct 12. doi:10.1186/s40248-016-0073-0
- Krylov V, Greuel J. Are bronchodilator nebulizers superior to MDIs for the treatment of acute asthma exacerbations? Evidence-Based Practice. 2018;21(6):3. doi:https://doi.org/10.1097/01.EBP.0000545148.85715.aa
- Kress JP, Noth I, Gehlbach BK, et al. The utility of albuterol nebulized with heliox during acute asthma exacerbations. Am J Respir Crit Care Med. 2002;165(9):1317-1321. doi:10.1164/rccm.9907035
- Ueoka m, antonette subia g, lai hipp c, tawata w, chung-esaki h. Ketamine infusion for refractory status asthmaticus: a case series. Chest. 2021;160(4):a5. doi:https://doi.org/10.1016/j.chest.2021.07.062
Additional Resources
- British Guideline on the Management of Asthma Quick Reference Guide SIGN158.; 2019. https://www.sign.ac.uk/media/1383/qrg158.pdf
- How Does Asthma work? https://www.youtube.com/watch?v=PzfLDi-sL3w
Reviewed and Edited By
Arif Alper Cevik, MD, FEMAT, FIFEM
Prof Cevik is an Emergency Medicine academician at United Arab Emirates University, interested in international emergency medicine, emergency medicine education, medical education, point of care ultrasound and trauma. He is the founder and director of the International Emergency Medicine Education Project – iem-student.org, chair of the International Federation for Emergency Medicine (IFEM) core curriculum and education committee and board member of the Asian Society for Emergency Medicine and Emirati Board of Emergency Medicine.
