How to manage type 2 respiratory failure in Chronic Obstructive Pulmonary Disease (COPD)?

Management of Type 2 Respiratory Failure in COPD

Non-invasive ventilation (NIV) should be started when a pH <7.35, a PaCO2 of ≥6.5 kPa and respiratory rate >23 breaths/min persists or develops after an hour of optimal medical therapy. 1

Initial Assessment and Oxygen Therapy

• Arterial blood gas (ABG) measurement is essential to diagnose and quantify the severity of acute hypercapnic respiratory failure (AHRF) before starting treatment 1
• Use controlled oxygen therapy with a target saturation of 88-92% to reduce mortality and the frequency and severity of AHRF 1
• Oxygen administration should start at a low dose (24% by Venturi mask or 1-2 L/min by nasal cannulae) 1
• Venturi masks are preferred over nasal prongs as they maintain adequate oxygenation for longer periods and deliver more accurate oxygen concentrations 2
• Monitor arterial blood gases regularly and adjust oxygen doses to achieve target saturation without elevating PaCO2 by >1.3 kPa or lowering pH to <7.25 1

Pharmacological Management

• Administer nebulized bronchodilators: β-agonist (salbutamol 2.5-5 mg or terbutaline 5-10 mg) or anticholinergic (ipratropium bromide 0.25-0.5 mg) 1
• For severe exacerbations or poor response to single agents, combine both bronchodilator types 1
• Continue nebulized bronchodilators for 24-48 hours or until clinical improvement, then switch to metered dose inhalers 1
• Consider a 7-14 day course of systemic corticosteroids (prednisolone 30 mg/day or hydrocortisone 100 mg if oral route not possible) 1
• If response is inadequate, consider intravenous aminophylline by continuous infusion (0.5 mg/kg/hour) with daily monitoring of blood levels 1
• Administer antibiotics if indicated for exacerbation 1

Non-Invasive Ventilation (NIV)

• In approximately 20% of AHRF cases secondary to COPD exacerbation, optimized medical therapy with controlled oxygen will normalize arterial pH 1
• Start NIV when pH <7.35, PaCO2 ≥6.5 kPa, and respiratory rate >23 breaths/min persists after one hour of optimal medical therapy 1
• For patients with PaCO2 between 6.0 and 6.5 kPa, NIV should be considered 1
• NIV reduces intubation rates, mortality, and duration of hospital stays, particularly in mild to moderate respiratory acidosis 3
• Document an individualized patient plan at the start of treatment regarding measures to be taken if NIV fails 1
• Chest radiography is recommended but should not delay NIV initiation in severe acidosis 1

Invasive Mechanical Ventilation

• Consider invasive intermittent positive pressure ventilation (IPPV) in patients with pH <7.26 and rising PaCO2 who fail to respond to NIV and controlled oxygen therapy 1
• Factors favoring IPPV use include: first episode of respiratory failure, acceptable quality of life/activity level, and identifiable reversible cause (e.g., pneumonia) 1
• Factors discouraging IPPV use: previously documented severe COPD unresponsive to therapy, poor quality of life despite maximal therapy, and severe comorbidities 1
• In patients requiring invasive ventilation, management of auto-PEEP is the priority, achieved by reducing airway resistance and decreasing minute ventilation 4

Additional Supportive Measures

• Consider doxapram (respiratory stimulant) in patients with acidosis (pH <7.26) and/or hypercapnia as a temporary measure (24-36 hours) until the underlying cause is controlled 1
• Administer diuretics if peripheral edema and raised jugular venous pressure are present 1
• Provide prophylactic subcutaneous heparin for patients with acute-on-chronic respiratory failure 1
• Respiratory stimulants like almitrine have not shown evidence of improved survival and are not recommended 1
• Heliox does not reduce rates of intubation, length of mechanical ventilation, or mortality in AECOPD 1

Long-term Management

• Long-term oxygen therapy (LTOT) improves survival in patients with chronic respiratory failure 1
• Criteria for LTOT: stable respiratory failure with PaO2 ≤7.3 kPa (55 mmHg) despite optimal therapy 1
• Use LTOT for at least 15 hours/day (preferably longer) including during sleep 1
• Flow of 1.5-2.5 L/min through nasal cannulae is usually adequate to achieve PaO2 >8.0 kPa (60 mmHg) 1
• Consider non-invasive positive pressure ventilation for long-term use in patients with severe nocturnal hypoxemia or respiratory muscle weakness 1
• Pulmonary rehabilitation improves exercise tolerance and quality of life in patients with COPD 1

Monitoring and Follow-up

• Regularly monitor arterial blood gases to assess response to therapy 1
• Assess for and treat reversible causes contributing to respiratory failure 1
• Evaluate the need for long-term oxygen therapy after stabilization 1
• Reassess oxygen requirements at least annually for patients on LTOT 1