FFS: COPD
Chronic Obstructive Pulmonary Disease (COPD) is a major global public health issue, characterised by partially reversible airflow obstruction with components of:
- Emphysema
- Chronic bronchitis
- Asthma
Exacerbations are a common ED presentation, often requiring ventilatory support. Non-invasive ventilation (NIV) is the mainstay of acute hypercapnic respiratory failure, but remains underutilised.
Early discussions about intubation limitations and care planning are critical.
Pathophysiology
Definitions
- Chronic bronchitis: Productive cough ≥3 months/year for ≥2 years
- Emphysema: Destruction of distal airways with alveolar wall destruction
Diagnosis
- Formal diagnosis = clinical assessment + lung function testing
- GOLD staging system used to classify severity
Causes
Category | Examples |
---|---|
Smoking | Most common cause worldwide |
Occupational/environmental | Pollutants, industrial exposure |
Congenital | Alpha-1 antitrypsin deficiency, CF |
Exacerbations
Definition
An acute worsening of baseline symptoms (dyspnoea, cough, sputum) requiring a change in therapy.
Common Triggers
- Infection (bacterial/viral)
- CCF
- ACS
- PE
- Poor medication compliance
- Continued smoking
- Environmental pollutants
No clear cause in some cases — may reflect natural disease progression.
Infective Exacerbations — Common Pathogens
- Strep pneumoniae
- Haemophilus influenzae
- Moraxella catarrhalis
- Later: Staph aureus, Pseudomonas aeruginosa (esp. severe disease)
Clinical Assessment
Key History
- Patient’s own severity rating
- Previous ICU/NIV/intubation
- Home oxygen/steroid use
- Duration of current episode
- Change in sputum (volume, colour)
- Functional baseline
- Advanced care plans
Key Examination
- Consciousness
- Work of breathing
- Speech
- Pulse rate
- Air entry (wheeze, silence)
- Cyanosis (late sign)
- PEFR/FEV1 (if possible)
- ABG/VBG (esp. CO₂ trend)
Severity Classification
Parameter | Mild | Moderate | Severe/Life-Threatening |
---|---|---|---|
Consciousness | Normal | Normal | Altered |
Respiratory effort | Normal | ↑ WOB | Exhaustion ± paradoxical breathing |
Speech | Sentences | Phrases | Words/none |
Pulse rate | <100 | 100–120 | >120 or bradycardia |
Breath sounds | Wheeze | Loud wheeze | Silent chest, poor entry, PTX |
PEFR (% predicted) | >75% | 50–75% | <40% or <100 L/min |
FEV1 (% predicted) | >75% | 50–75% | <40% or <1L |
SpO₂ | >95% | 92–95% | <92% |
PaCO₂ | Normal | >40 = severe | >45 mmHg (respiratory failure) |
PaO₂ | Normal | May drop | <60 mmHg (respiratory failure) |
Investigations
Test | Notes |
---|---|
FBC, CRP | Infection screen |
U&Es, Glucose | Monitor for salbutamol-induced hypokalaemia |
ABG/VBG | PaCO₂ >45 = respiratory failure; VBG suitable in many cases |
CXR | Look for infection, CCF, pneumothorax |
ECG | Common arrhythmias: MFAT, AF |
Sputum M&C | If cooperative |
Cardiac enzymes | Consider if chest pain or ACS suspected |
BNP | If CCF suspected |
Blood cultures | If febrile/unwell |
Management
1. ABC + Monitoring
- Pulse oximetry
- ECG monitoring
- BP monitoring
- Avoid unnecessary arterial lines early
2. Oxygenation
- Priority: oxygen first (SaO₂ ≥90–92%)
- Accept 88% in severe disease
- Start with nasal prongs or Hudson mask
- Consider Venturi mask (28%) for CO₂ retainers
- Avoid excessive O₂ due to Haldane effect
3. Humidification
- Use heated humidifiers for long-term O₂
4. High Flow Nasal Oxygen
- Tolerable alternative
- Some CPAP effect, less effective for hypercapnia
5. Non-Invasive Ventilation (NIV)
- Indicated when:
- Oxygenation inadequate
- Rising CO₂
- Exhaustion
- BIPAP preferred (active ventilatory support)
- Monitor for barotrauma
6. Bronchodilators
- Salbutamol 5 mg neb PRN (can be continuous)
- Ipratropium 500 mcg q20min × 3, then hourly
7. Corticosteroids
- IV dexamethasone 10 mg TDS
or
Hydrocortisone 100 mg IV QID - Oral prednisolone 30–50 mg daily × up to 2 weeks
8. Antibiotics
- Cefotaxime 1–2 g IV
- +/- Azithromycin 500 mg IV
9. Antivirals
- If influenza likely → Oseltamivir
10. Aminophylline
- Not recommended routinely due to side effects
11. Sedation
- Avoid sedation unless required to tolerate NIV
Intubation & Mechanical Ventilation
Considerations
- Diagnosis confirmed
- Reversible cause
- Functional baseline
- Patient preferences/ACP
Indications
- Exhaustion
- ↓ LOC, confusion
- ↑ CO₂
- SpO₂ <88% or PaO₂ <60 despite NIV
Permissive Hypercapnia Strategy
Setting | Target |
---|---|
FiO₂ | Start 100%, then titrate |
Vt | ≤6 mL/kg IBW (↓ to 3–4 mL/kg if needed) |
Rate | ↓ to 6–8/min |
PEEP | Off |
I:E Ratio | ≥1:4 |
pH tolerance | >7.1 |
Avoid bicarbonate. Do not treat hypercapnia by ↑ RR — risk of barotrauma.
Additional Measures
- Deep sedation ± paralytics
- NG tube for gastric decompression
- Disconnect ventilator for dynamic hyperinflation
- Monitor SpO₂, capnometry, chest rise (not alarms)
- Adjust alarms for low Vt/PIP if needed
Disposition
Admit:
- Almost all patients
- NIV usually excludes short-stay suitability
- HDU/ICU if:
- Poor response
- Prior ICU/NIV
- Advanced care planning in place
End-of-life Planning
- ACP does not exclude NIV trial
- Consider palliation if unresponsive to NIV after discussion
Follow-Up
- Refer to respiratory outreach services
- Aim: education, care plans, reduce readmissions
- Early treatment may prevent progression
References
FOAMed
- Nickson C. Acute Severe Asthma. CCC
- Nickson C. Non-invasive ventilation (NIV) and asthma. CCC
- Flower O. Severe asthma management. LITFL
- Guthrie K. Case of Acute Severe Asthma. LITFL
- Cadogan M. EMI 026 Acute Asthma Guidelines. LITFL
Resources
Fellowship Notes
Educator, magister, munus exemplar, dicata in agro subitis medicina et discrimine cura | FFS |