What are the recommended asthma maintenance therapy and acute exacerbation management protocols for the NAC OSCE Canada exam?

Asthma Treatment and Exacerbation Management - NAC OSCE Canada

CHRONIC ASTHMA MAINTENANCE THERAPY

For chronic asthma, use a stepwise approach based on severity, with inhaled corticosteroids (ICS) as the foundation of treatment starting at Step 2. 1

Step 1: Intermittent Asthma

• Preferred: Short-acting beta-agonist (SABA) as needed only
• Examples: Salbutamol/albuterol 2 puffs PRN

Step 2: Mild Persistent Asthma

• Preferred: Low-dose ICS daily
• Alternatives: Leukotriene receptor antagonist (montelukast), cromolyn, or nedocromil 1
• Example: Fluticasone 100-250 mcg daily

Step 3: Moderate Persistent Asthma

• Preferred: Low-to-medium dose ICS + long-acting beta-agonist (LABA)
• Alternative: Medium-dose ICS alone, OR low-to-medium dose ICS + leukotriene modifier 1, 2
• Example: Fluticasone/salmeterol (Advair) 250/50 mcg twice daily

Step 4: Moderate-Severe Persistent Asthma

• Preferred: Medium-dose ICS + LABA
• Alternative: Medium-dose ICS + leukotriene modifier 1

Step 5: Severe Persistent Asthma

• Preferred: High-dose ICS + LABA
• Consider: Omalizumab for allergic asthma 1

Step 6: Very Severe Persistent Asthma

• Preferred: High-dose ICS + LABA + oral corticosteroids
• Consider: Omalizumab for allergic asthma 1

Key Point: Never use SABA alone for persistent asthma - always add ICS to reduce exacerbation risk and mortality 3, 4.

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ACUTE ASTHMA EXACERBATION MANAGEMENT

For acute exacerbations, immediately give oxygen, repetitive SABA, and systemic corticosteroids - these three medications form the cornerstone of emergency treatment. 5, 6, 7

Initial Assessment - Severity Classification

Mild Exacerbation:

• Dyspnea only with activity
• Peak flow ≥70% predicted
• Speaks in sentences

Moderate Exacerbation:

• Dyspnea interferes with activity
• Peak flow 40-69% predicted
• Speaks in phrases
• Respiratory rate increased

Severe Exacerbation:

• Dyspnea at rest
• Peak flow <40% predicted
• Speaks in words only
• Respiratory rate >30/min
• Heart rate >120 bpm
• Accessory muscle use

Life-Threatening Features:

• Silent chest, cyanosis, poor respiratory effort
• Altered consciousness, exhaustion
• Oxygen saturation <92%
• Peak flow <33% predicted 5, 8, 9

Emergency Treatment Protocol

IMMEDIATE ACTIONS (First Hour):

1. Oxygen: Start immediately to maintain SpO2 ≥90% (≥95% in children) 5, 6

2. SABA - First Line:

   • Adults: Salbutamol 2.5-5 mg nebulized OR 4-8 puffs MDI with spacer
   • Children: Salbutamol 2.5 mg (age <2) or 5 mg (age ≥2) nebulized
   • Repeat every 20 minutes for 3 doses 5, 6
   • Can give continuously at 10-15 mg/hour for severe cases 5

3. Systemic Corticosteroids - Give Early:

   • Adults: Prednisone 40-60 mg PO OR hydrocortisone 200 mg IV
   • Children: Prednisone 1-2 mg/kg (max 60 mg) PO
   • Give within first hour - no benefit to IV over oral if patient can swallow 5, 8, 6

4. Ipratropium Bromide - Add for Severe/Life-Threatening:

   • Adults: 0.5 mg nebulized with SABA every 20 minutes for 3 doses
   • Children: 0.25-0.5 mg nebulized
   • Can mix with SABA in same nebulizer 5, 6
   • Important: Only beneficial in first 3 hours; no benefit once hospitalized 5

Reassess After 1 Hour

Good Response (Peak flow >70%, no distress):

• Continue SABA every 3-4 hours
• Continue oral corticosteroids
• Consider discharge if sustained improvement

Incomplete Response (Peak flow 40-69%, persistent symptoms):

• Continue SABA every 1-2 hours
• Continue oxygen and corticosteroids
• Consider admission

Poor Response (Peak flow <40%, severe symptoms persist):

• Admit to hospital
• Continue frequent SABA
• Consider IV magnesium sulfate 2 grams over 20 minutes 10
• Consider IV salbutamol or subcutaneous epinephrine 0.3-0.5 mg for life-threatening cases 5

Medications NOT Recommended in First 4 Hours

• Aminophylline/theophylline - no benefit, increases side effects 6
• Antibiotics - unless clear bacterial infection 8
• Sedatives - absolutely contraindicated 8

Criteria for ICU Admission

• Worsening hypoxia despite 60% oxygen
• Hypercapnia (PaCO2 >45 mmHg)
• Exhaustion, confusion, drowsiness
• Respiratory arrest 8

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DISCHARGE PLANNING

Discharge when:

• Peak flow >60-80% predicted AND sustained for 1 hour
• Minimal symptoms at rest
• No nocturnal symptoms
• Oxygen saturation >90% on room air 8, 10

Discharge Medications:

1. Prednisone 40-60 mg daily for 5-10 days (no taper needed) 5, 6
2. Start or increase ICS - all patients need this 6
3. SABA for rescue - continue as needed
4. Written asthma action plan - mandatory 9, 4

Follow-up: Within 2-7 days with primary care or respirologist 6, 10

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Common Pitfalls to Avoid

• Don't use SABA alone for maintenance - always add ICS to prevent death 3, 4
• Don't delay corticosteroids - give in first hour of exacerbation 5, 6
• Don't use aminophylline in acute setting - no benefit, more side effects 6
• Don't forget ipratropium for severe exacerbations - reduces hospitalizations 5
• Don't discharge without ICS - prevents future exacerbations 6
• Don't use IV corticosteroids unless patient vomiting - oral works equally well 5