What is the management approach for a patient presenting with acute asthma, characterized by symptoms such as wheezing, shortness of breath, chest tightness, and cough?

Management of Acute Asthma Exacerbation

Acute asthma requires immediate administration of high-dose inhaled beta-agonists (salbutamol 5 mg or terbutaline 10 mg via nebulizer), systemic corticosteroids (prednisolone 30-60 mg orally or hydrocortisone 200 mg IV), and oxygen to maintain saturation >90%, with severity assessment using objective measures including peak expiratory flow, respiratory rate, heart rate, and ability to complete sentences. 1, 2

Clinical Presentation and Chief Complaints

Cardinal Symptoms

• Patients present with progressive worsening of shortness of breath, cough, wheezing, and chest tightness that does not respond to usual bronchodilator therapy 1
• The exacerbation is characterized by acute or subacute worsening of symptoms and lung function compared to the patient's normal status, requiring a change in treatment 1

Risk Factors Requiring Special Attention

• Previous severe exacerbation requiring intubation or ICU admission, two or more hospitalizations or >3 emergency department visits in the past year, and use of >2 canisters of short-acting beta-agonist per month identify patients at high risk of asthma-related death 1
• Poor asthma control, underuse or poor adherence to treatment, comorbidities, aspirin or NSAID use, and socioeconomic disadvantage increase exacerbation risk 1

Physical Examination Findings

Severity Assessment - Severe Exacerbation Features

• Inability to complete sentences in one breath is a critical marker of severe airflow obstruction 1, 2
• Respiratory rate >25 breaths/min in adults indicates severe exacerbation 1, 3, 2
• Heart rate >110 beats/min in adults signals severe disease 1, 3, 2
• Use of accessory muscles of respiration, degree of breathlessness, and amount of wheezing should be assessed 1
• Peak expiratory flow (PEF) <50% of predicted or personal best defines severe exacerbation 1, 2

Life-Threatening Features Requiring Immediate ICU Consideration

• Silent chest, cyanosis, or feeble respiratory effort are ominous signs 1, 2
• Bradycardia or hypotension indicate impending respiratory arrest 1, 2
• Altered mental status, exhaustion, confusion, or coma require immediate intervention 1, 2
• PEF <33% of predicted or personal best is life-threatening 1, 2
• Normal or elevated PaCO₂ (≥42 mmHg) in a breathless asthmatic patient is a marker of very severe, life-threatening attack - this is critical because patients typically hyperventilate early in exacerbations, causing PaCO₂ to drop 3, 2, 4

Common Pitfall in Assessment

• Normal oxygen saturation does not exclude severe or life-threatening asthma exacerbation - patients can maintain adequate oxygenation through increased work of breathing while developing dangerous hypercapnia 4
• Physicians' subjective assessments of airway obstruction are often inaccurate; objective measures via peak flow or FEV₁ and pulse oximetry are essential 5
• The severity of airflow limitation correlates poorly with clinical signs alone 6

General Examination and Monitoring

Objective Measurements (Essential, Not Optional)

• Pulse oximetry should be performed immediately, with oxygen saturation cut-off for detecting hypoxemia at 90-92% 1
• Peak expiratory flow monitoring should be measured before treatment and 15-30 minutes after bronchodilator administration 1, 2
• Arterial blood gas measurements must always be obtained in patients with acute severe asthma admitted to hospital 1, 4
• Severe hypoxia (PaO₂ <8 kPa or 60 mmHg) despite oxygen therapy is life-threatening 3, 2

Vital Signs Monitoring

• Continuous pulse oximetry with target SaO₂ >92% (>95% in pregnant patients or those with heart disease) 2, 4
• Respiratory rate and heart rate should be monitored every 15-30 minutes initially 1, 2
• Degree of agitation and level of consciousness are important indicators 1

Management Algorithm

Immediate Initial Treatment (First 15-30 Minutes)

• Administer oxygen 40-60% via mask or nasal cannulae to maintain SaO₂ >90% (>95% in pregnant patients or those with heart disease) 2, 4
• Give high-dose inhaled beta-agonist: salbutamol 5 mg or terbutaline 10 mg via oxygen-driven nebulizer, or 4-8 puffs via MDI with spacer 1, 2, 7
• Administer systemic corticosteroids immediately: prednisolone 30-60 mg orally or IV hydrocortisone 200 mg - clinical benefits require 6-12 hours minimum, so early administration is critical 1, 2, 5

Reassessment at 15-30 Minutes

• Measure PEF or FEV₁ and assess symptoms and vital signs 2
• If PEF remains <50% predicted or severe features persist, repeat nebulized beta-agonist every 20 minutes for 3 doses (total of 3 doses in first hour) 1, 2

Treatment for Moderate to Severe Exacerbations

• Add ipratropium bromide 0.5 mg to nebulized beta-agonist every 20 minutes for 3 doses, then as needed - this combination reduces hospitalizations, particularly in patients with severe airflow obstruction 1, 2
• Continue oxygen to maintain target saturation 2, 4
• Ensure systemic corticosteroids have been administered 2

Adjunctive Therapy for Severe Refractory Cases

• Consider intravenous magnesium sulfate 2 g over 20 minutes for patients with severe exacerbations (PEF <40% predicted) not responding to initial therapy or with life-threatening features - this significantly increases lung function and decreases hospitalization necessity 2, 8, 9
• Obtain chest X-ray to exclude pneumothorax, consolidation, or pulmonary edema if treatment failure occurs 2

Reassessment at 60-90 Minutes (After 3 Doses of Bronchodilator)

Good Response (PEF ≥70% predicted):

• Minimal symptoms, stable vital signs, oxygen saturation stable on room air 2
• Observe for 30-60 minutes after last bronchodilator dose 2
• Discharge with oral corticosteroids for 5-10 days (no taper needed for courses <10 days) 2, 10
• Initiate or continue inhaled corticosteroids 2, 10
• Provide written asthma action plan and verify inhaler technique 2
• Arrange follow-up within 1 week 1

Incomplete Response (PEF 40-69% predicted):

• Continue intensive treatment with nebulized beta-agonists every 1-4 hours 2, 7
• Admit to hospital ward 2
• Continue systemic corticosteroids and oxygen 2

Poor Response (PEF <40% predicted or life-threatening features):

• Immediate hospital admission with consideration for ICU transfer 2
• Continue nebulized beta-agonists every 15 minutes if no improvement 2
• Ensure IV magnesium sulfate has been administered 2
• Consider IV aminophylline 250 mg over 20 minutes (caution if patient already taking oral theophyllines) 1, 2

Critical Pitfalls to Avoid in Management

• Never administer sedatives of any kind to patients with acute asthma - this is absolutely contraindicated 1, 2
• Do not delay corticosteroid administration - they must be given immediately, not after "trying bronchodilators first" 2
• Do not underestimate severity - patients, families, and clinicians frequently fail to recognize dangerous exacerbations due to inadequate objective measurements 2, 8
• Avoid bolus aminophylline in patients already taking oral theophyllines 1, 2
• Do not routinely use antibiotics unless strong evidence of bacterial infection (pneumonia or sinusitis) exists 2, 9
• Avoid methylxanthines as routine therapy due to erratic pharmacokinetics and significant side effects 8, 9

Hospital Admission Criteria

• Any life-threatening features present 1, 2
• Features of severe attack persisting after initial treatment, especially PEF <33% 1, 2
• PEF <50% predicted after 1-2 hours of treatment 2
• Lower threshold for admission if presentation occurs in afternoon/evening, recent nocturnal symptoms, previous severe attacks, or concerning social circumstances 1, 2

ICU Transfer Indications

• Deteriorating PEF despite treatment 2, 4
• Worsening or persisting hypoxia 2, 4
• Rising PaCO₂ or respiratory acidosis 2, 4
• Exhaustion, confusion, drowsiness, or impending respiratory arrest 2, 4
• Silent chest with minimal air movement 2

Intubation Considerations

• Do not delay intubation once it is deemed necessary - it should be performed semi-electively before respiratory arrest occurs 2, 8
• Consider other treatments (IV magnesium, heliox) before resorting to intubation 1, 9
• Transfer to ICU should be accompanied by a physician prepared to intubate 2

Discharge Planning and Follow-up

• Ensure PEF reaches ≥70% of predicted or personal best before discharge 2
• Continue oral corticosteroids for 5-10 days (no taper needed for courses <10 days) 2, 10
• Initiate or increase inhaled corticosteroids 2, 10
• Provide written asthma action plan 2
• Verify inhaler technique 1, 2
• Arrange follow-up within 1 week in primary care and within 4 weeks in specialist clinic 1, 2