A 52-year-old woman with COPD (GOLD Stage 2) on maintenance therapy with tiotropium presents with acute exacerbation. She reports increased dyspnoea, cough, and sputum production for 3 days. On examination: RR 26/min, SpO₂ 88% on room air, diffuse wheeze. What is the most appropriate immediate next step in management?

Explanation

## Clinical Context This patient has **acute COPD exacerbation** with signs of respiratory distress (RR 26, SpO₂ 88%) despite being on maintenance LAMA therapy (tiotropium). Immediate symptom relief is required. ## COPD Exacerbation Management Hierarchy | Priority | Intervention | Rationale | |----------|--------------|----------| | **Immediate** | SABA ± SAMA via nebuliser | Rapid bronchodilation; symptom relief within minutes | | **Concurrent** | Supplemental O₂ (target SpO₂ 88–92%) | Hypoxemia correction | | **Early** | Systemic corticosteroids (oral/IV) | Anti-inflammatory; reduces exacerbation duration | | **Concurrent** | Antibiotics (if signs of infection) | Bacterial infection in 50% of exacerbations | | **Ongoing** | Continue maintenance therapy | LAMA/LABA prevents relapse | **Key Point:** In acute exacerbation, **short-acting agents (SABA ± SAMA) are first-line** for rapid bronchodilation, regardless of maintenance therapy. Nebulised delivery ensures rapid systemic absorption and onset within 5–15 minutes [cite:Harrison 21e Ch 298]. ## Mechanism of SABA in Acute Setting **High-Yield:** SABAs (e.g. salbutamol, terbutaline) activate **β₂-adrenergic receptors** on bronchial smooth muscle, increasing intracellular cAMP and causing rapid smooth muscle relaxation. This provides **immediate symptom relief** in exacerbation. **Clinical Pearl:** Combination of SABA + SAMA (e.g. salbutamol + ipratropium) is superior to SABA monotherapy in acute exacerbation because: - SAMA (anticholinergic) blocks vagal bronchoconstriction - Synergistic bronchodilation - Greater FEV₁ improvement than either agent alone [cite:KD Tripathi 8e Ch 29] ## COPD Exacerbation Management Flow ```mermaid flowchart TD A[Acute COPD exacerbation<br/>Dyspnoea, SpO₂ 88%, RR 26]:::urgent A --> B[Assess severity]:::decision B --> C[Mild-moderate: outpatient]:::outcome B --> D[Severe: hospital admission]:::outcome A --> E[Immediate interventions]:::action E --> F[SABA ± SAMA nebulised<br/>Repeat q 30-60 min PRN]:::action E --> G[Supplemental O₂<br/>Target SpO₂ 88-92%]:::action E --> H[Assess response at 1-2 hours]:::decision H -->|Good| I[Continue SABA + systemic CS + Abx]:::action H -->|Poor| J[Consider IV magnesium<br/>or non-invasive ventilation]:::urgent ``` ## Why SABA Nebuliser is Correct 1. **Rapid onset:** Nebulised SABA achieves bronchodilation in 5–15 minutes (vs. 30–60 min for oral agents) 2. **High local concentration:** Direct delivery to airways maximizes effect 3. **Standard of care:** GINA/GOLD guidelines recommend SABA as first-line for acute exacerbation 4. **Reversibility assessment:** Response to SABA helps confirm COPD diagnosis and guides further therapy