Key Facts

An acute exacerbation of COPD (AECOPD) is defined as a sustained worsening of the patient's symptoms from their usual stable state which is beyond normal day-to-day variations and is acute in onset, commonly requiring a change in regular medication.

Epidemiology

• Average 1-3 exacerbations per year per COPD patient
• ~115,000 COPD admissions per year in England
• Leading cause of emergency medical admission in the UK
• Winter predominance (viral triggers)
• 30-day readmission rate ~25%

Aetiology

• Viral infections (~50-70%): rhinovirus, influenza, parainfluenza, RSV, adenovirus
• Bacterial infections (~30-50%): Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, Pseudomonas (if severe COPD/bronchiectasis)
• Environmental: air pollution, cold weather, allergens
• Non-infectious: PE (~25% of AECOPD admissions may have concurrent PE), pneumothorax, heart failure, non-adherence

Pathophysiology

• Infection or irritant triggers enhanced airway inflammation (neutrophilic)
• Increased mucus production and bronchospasm worsen airflow obstruction
• Dynamic hyperinflation increases work of breathing
• V/Q mismatch worsens causing hypoxaemia
• In severe cases, type 2 respiratory failure (hypoxia + hypercapnia) develops due to respiratory muscle fatigue

Typical Presentation

• Increased breathlessness beyond usual level
• Increased sputum volume and/or purulence
• Increased cough
• Wheeze
• Chest tightness
• Reduced exercise tolerance
• May have fever, confusion (hypercapnia), or ankle swelling (cor pulmonale)

Severity Assessment

• Mild: managed with increased bronchodilator use alone
• Moderate: requires systemic corticosteroids and/or antibiotics
• Severe: requires hospitalisation or ED attendance

Red Flags

• Confusion or reduced consciousness (CO₂ narcosis)
• SpO₂ <88% on air
• Respiratory rate >30/min
• Use of accessory muscles, paradoxical abdominal movement
• Cyanosis
• Peripheral oedema (acute cor pulmonale)
• Unable to speak in full sentences
• Failure to respond to initial treatment
• pH <7.35 (respiratory acidosis)
• Significant comorbidities (heart failure, pneumonia)

Bedside

• ABG: essential if SpO₂ <92% or severe exacerbation — assess pH, PaCO₂, PaO₂, HCO₃⁻, lactate
• Pulse oximetry: continuous; target SpO₂ 88-92%
• ECG: arrhythmia, right heart strain, exclude ACS
• Sputum colour chart: green/purulent suggests bacterial infection

Bloods

• FBC: WCC (infection), eosinophils, haemoglobin
• CRP: elevated in infective exacerbation
• U&Es: renal function, electrolytes
• Blood cultures: if pyrexial or severe sepsis
• BNP/NT-proBNP: if heart failure suspected
• Theophylline level: if on maintenance theophylline
• Procalcitonin: may help guide antibiotic decisions (reducing unnecessary antibiotics)

Imaging

• Chest X-ray: exclude pneumonia, pneumothorax, pleural effusion, pulmonary oedema
• CTPA: if PE suspected (25% of severe AECOPD have concurrent PE)

Special Tests

• Sputum MC&S: if frequent exacerbations, failure to respond to empirical antibiotics, or bronchiectasis
• Spirometry: NOT performed during acute exacerbation; reassess 4-6 weeks after recovery

Non-pharmacological

• Controlled oxygen therapy: 24% or 28% Venturi mask initially (target SpO₂ 88-92%)
• Titrate oxygen based on repeat ABG at 30-60 minutes
• Sit patient upright
• Chest physiotherapy for sputum clearance

Pharmacological

Bronchodilators:

• Nebulised salbutamol 2.5-5mg QDS (driven by compressed air in hypercapnic patients, with nasal O₂ at 2L/min)
• Nebulised ipratropium bromide 500mcg QDS

Corticosteroids:

• Prednisolone 30mg OD for 5 days (REDUCE trial showed 5 days equivalent to 14 days)
• IV hydrocortisone 100mg if unable to swallow

Antibiotics (if purulent sputum or consolidation):

• Amoxicillin 500mg TDS for 5 days (first-line)
• Doxycycline 200mg loading then 100mg OD or clarithromycin 500mg BD if penicillin allergic
• Co-amoxiclav 625mg TDS or piperacillin-tazobactam if Pseudomonas risk or severe

NIV (BiPAP):

• Indicated for persistent respiratory acidosis (pH 7.25-7.35, PaCO₂ >6 kPa) despite 1 hour of optimal medical therapy
• Typical settings: IPAP 12-20 cmH₂O, EPAP 4-6 cmH₂O, back-up rate 12-15
• If pH <7.25 or failure to improve — consider ITU referral for invasive ventilation

Other:

• VTE prophylaxis: LMWH (enoxaparin 40mg SC OD) unless contraindicated
• IV aminophylline: rarely used; consider if poor response (loading 5mg/kg over 20 min)

Surgical/Interventional

• Intubation and mechanical ventilation if NIV fails or pH <7.25
• Chest drain if pneumothorax

Referral Criteria

• ICU referral if pH <7.25 or failing NIV
• Respiratory team review for all admitted AECOPD patients
• Pulmonary rehabilitation referral within 4 weeks of discharge
• Specialist review if frequent exacerbations (≥2/year) or diagnostic uncertainty

• In-hospital mortality: ~5-10%
• 30-day mortality: ~10%
• 90-day mortality: ~15%
• 30-day readmission rate: ~25%
• 1-year mortality after hospitalised AECOPD: ~25%
• Each exacerbation associated with ~5-8% decline in FEV₁
• Frequent exacerbations (≥2/year) are an independent predictor of mortality
• Post-exacerbation pulmonary rehabilitation reduces readmissions by 30-50%
• NIV reduces mortality by ~50% in acidotic AECOPD (vs standard care)

DECAF Score (Hospital Mortality Predictor)

NIV Settings Summary