What is the diagnosis and treatment for Type 2 (Hypercapnic) respiratory failure?

From the Guidelines

Type 2 respiratory failure should be managed with non-invasive ventilation (NIV) when a pH <7.35, a PaCO2 of ≥6.5 kPa, and RR >23 breaths/min persist or develop after an hour of optimal medical therapy, as recommended by the BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults 1.

Key Considerations

• Initial management includes oxygen therapy, typically starting with controlled low-flow oxygen (1-2 L/min) to avoid suppressing respiratory drive in chronic CO2 retainers.
• NIV, such as BiPAP, is often the first-line intervention, with settings typically starting at IPAP 10-12 cmH2O and EPAP 4-5 cmH2O, titrated based on response.
• For patients with a PaCO2 between 6.0 and 6.5 kPa, NIV should be considered, as per the BTS/ICS guideline 1.
• Oxygen enrichment should be adjusted to achieve SaO2 88–92% in all causes of acute hypercapnic respiratory failure (AHRF) treated by NIV, as recommended by the BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults 1.

Pharmacological Management

• Bronchodilators, such as albuterol 2.5 mg nebulized every 4-6 hours, may be used for bronchospasm.
• Corticosteroids, such as prednisone 40-60 mg daily for 5-7 days, may be used for inflammation.
• Antibiotics may be used if infection is present.

Common Causes

• COPD
• Neuromuscular disorders
• Chest wall deformities
• Central nervous system depression from drugs or neurological conditions

Addressing the Underlying Cause

• Crucial for effective management and preventing recurrence of respiratory failure.
• Treatment should be based on the results of previous blood gas estimations during acute exacerbations, as recommended by the BTS guideline for oxygen use in adults in healthcare and emergency settings 1.

From the Research

Definition and Causes of Type 2 Respiratory Failure

• Type 2 respiratory failure is characterized by high carbon dioxide levels (PaCO2 >6kPa) and is often seen in patients with chronic obstructive pulmonary disease (COPD) 2, 3, 4.
• The presence of respiratory failure predicts worse prognosis and higher mortality in patients with COPD 2.
• Oxygen therapy may lead to various adverse effects, including hypercapnia, particularly in patients with COPD, morbid obesity, asthma, cystic fibrosis, chest wall skeletal deformities, bronchiectasis, chest wall deformities, or neuromuscular disorders 3.

Treatment Options for Type 2 Respiratory Failure

• Supplemental oxygen therapy (SOT) and noninvasive ventilation (NIV) have been increasingly used to treat type 2 respiratory failure, aiming to improve both prognosis and quality of life 2, 4.
• The international guideline recommends a target oxygen saturation of 88% to 92% in patients with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) and other chronic lung diseases at risk of hypercapnia 3.
• High flow nasal oxygen therapy (HFNT) has potential additional benefits such as CO2 clearance, the ability to communicate and comfort, but its effectiveness as an initial management strategy for acute type 2 respiratory failure is still uncertain 5.
• Non-invasive positive pressure ventilation (NIV) has been shown to reduce intubation and mortality rates, and the duration of intensive care unit or hospital stays, particularly in the presence of mild to moderate respiratory acidosis 4.

Clinical Practice Guidelines for Oxygen Therapy

• The AARC Clinical Practice Guideline recommends aiming for an oxygen saturation range of 94-98% for most hospitalized patients, and 88-92% for those with COPD 6.
• The guideline also recommends promoting early initiation of high-flow oxygen (HFO), considering HFO to avoid escalation to noninvasive ventilation, and considering humidification for supplemental oxygen when flows > 4 L/min are used 6.