Start NIV when pH < 7.35 and PaCO2 > 45 mmHg (6.5 kPa) persist after initial treatment. Titrate IPAP quickly, target SpO2 88-92%, recheck the gas at 1-2 h, and decide early whether NIV is working.
At the bedside
Timed steps- 1
Optimise medical treatment
0-60 minControlled O2 to 88-92%, nebulised salbutamol 5 mg + ipratropium 500 mcg (air-driven), prednisolone 40 mg, antibiotics if purulent sputum or ventilated.
- 2
Decide on NIV
≤ 60 minpH < 7.35 and PaCO2 > 45 mmHg (6.5 kPa) persisting despite optimal medical therapy. pH < 7.25: NIV in HDU/ICU with intubation ready.
- 3
Settings
StartFull face (oronasal) mask. EPAP 4-5 cmH2O; IPAP 15 cmH2O, increasing to 20-30 cmH2O over 10-30 min as tolerated to reduce PaCO2. Backup rate 16-20. O2 entrained to SpO2 88-92%.
- 4
ABG
1-2 hImproving pH and RR = continue. No improvement: check mask leak, synchrony, settings, secretions; consider intubation.
- 5
ABG again
4-6 hContinue NIV as much as possible in the first 24 h, then wean during the day, keeping it overnight.
- 6
Ceiling of treatment
PlanDocument whether intubation is appropriate before starting NIV.
Bronchodilator
Salbutamol (albuterol)
- Dose
- 2.5-5 mg every 4-6 h (more often initially)
Bronchodilator
Ipratropium bromide
- Dose
- 500 mcg every 6 h
Systemic steroid
Prednisolone / hydrocortisone
- Dose
- 40 mg daily for 5 days
NIV settings for hypercapnic respiratory failure (BTS/ICS)
| Parameter | Initial | Titration |
|---|---|---|
| EPAP | 4-5 cmH2O | Increase for upper airway obstruction (OSA, obesity) or to offset intrinsic PEEP |
| IPAP | 15 cmH2O | Up to 20-30 cmH2O over 10-30 min |
| Backup rate | 16-20/min | Adjust to patient |
| I:E | 1:2-1:3 | Longer expiration in COPD |
| SpO2 | 88-92% | Adjust entrained O2 |
References
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NIV in hypercapnic COPD
Step 1 of ~4
Controlled O2 88-92%, bronchodilators, steroids; ABG
Based on Davidson AC, Banham S, Elliott M, et al. Educational use; follow local protocol.
Pathophysiology
Dynamic hyperinflation increases the work of breathing and intrinsic PEEP. NIV unloads the respiratory muscles (IPAP) and offsets intrinsic PEEP (EPAP), increasing alveolar ventilation and lowering PaCO2.
Evidence
- ERS/ATS 2017: strong recommendation for bilevel NIV in COPD exacerbation with acute or acute-on-chronic respiratory acidosis (pH ≤ 7.35).
- BTS/ICS 2016: start NIV when pH < 7.35 and PaCO2 > 6.5 kPa persist despite immediate medical therapy; specific titration advice.
Controversies
- Role of HFNC in mild hypercapnia (pH 7.25-7.35) if NIV is not tolerated: emerging data, not guideline-standard.
🇮🇳 India notes
- COPD in India is often driven by biomass fuel exposure, especially in women; tuberculosis sequelae can coexist (post-TB obstructive disease).
- The joint ICS/NCCP (India) guideline supports NIV for acute hypercapnic exacerbations.
References
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Test yourself
Module quiz · score 70% to complete the module
Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.