From the Guidelines
Hypercarbic respiratory failure is a life-threatening condition that requires immediate attention, and the most effective treatment approach is often non-invasive ventilation (NIV) with careful adjustment of settings to improve gas exchange and reduce morbidity and mortality, as recommended by the American Thoracic Society clinical practice guideline 1.
Causes and Characteristics
Hypercarbic respiratory failure occurs when the lungs cannot adequately remove carbon dioxide from the body, leading to abnormally high levels of CO2 in the blood (hypercapnia). This condition is characterized by a PaCO2 greater than 45 mmHg and is often accompanied by respiratory acidosis. The most common causes include:
- Chronic obstructive pulmonary disease (COPD)
- Severe asthma
- Neuromuscular disorders
- Chest wall deformities
- Central nervous system depression from drugs or neurological conditions
Treatment Approach
Treatment depends on the underlying cause but typically includes:
- Oxygen therapy (carefully administered to avoid worsening CO2 retention)
- Bronchodilators like albuterol (2-4 puffs every 4-6 hours) or ipratropium (2 puffs four times daily)
- Corticosteroids such as prednisone (40-60 mg daily for 5-7 days)
- Possibly antibiotics if infection is present
- Non-invasive ventilation like BiPAP (starting at inspiratory pressure 8-12 cmH2O and expiratory pressure 3-5 cmH2O) is often used to support breathing without intubation, as supported by the BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults 1.
Key Considerations
In patients with neuromuscular disorders (NMD) and chest wall deformities (CWD), NIV should be considered in any breathless/acutely unwell patient before respiratory acidosis develops, and the success of domiciliary NIV has made the management of any associated cardiomyopathy increasingly clinically relevant 1. The use of high-intensity NIV, with inspiratory pressures higher than those used in most previous randomized controlled trials, has shown potential to improve physiological parameters, clinical symptoms, and patient-centered outcomes in stable patients with COPD and chronic hypercapnia, as recommended by the American Thoracic Society clinical practice guideline 1.
From the Research
Definition and Treatment of Hypercarbic Respiratory Failure
- Hypercarbic respiratory failure, also known as type II respiratory failure, is characterized by high levels of carbon dioxide (CO2) in the blood, which can be life-threatening if left untreated 2.
- Non-invasive ventilation (NIV) with bi-level positive airway pressure is a commonly used treatment for hypercarbic respiratory failure, particularly in patients with chronic obstructive pulmonary disease (COPD) 3.
Benefits of Non-Invasive Ventilation
- NIV has been shown to decrease the risk of mortality and endotracheal intubation in patients with acute hypercapnic respiratory failure secondary to an acute exacerbation of COPD 3.
- NIV can also improve symptoms such as dyspnea and reduce the length of hospital stay 3.
- High-flow nasal cannula (HFNC) is a potential alternative treatment to NIV, but its effectiveness is still being studied, and the current evidence is limited 4.
Risk Factors for Intubation
- Patients with severe acute exacerbations of COPD are at risk of requiring intubation, and factors such as higher PaCO2 at admission, pneumonia as the cause of exacerbation, and early NIV failure can increase this risk 5.
- Early NIV failure is a potentially modifiable factor, and further studies are needed to investigate the mechanisms underlying NIV failure and explore potential therapeutic interventions 5.
Long-Term Non-Invasive Positive Pressure Ventilation
- Long-term non-invasive positive pressure ventilation (NPPV) can be beneficial in patients with chronic hypercapnic respiratory failure due to COPD, particularly when using high-intensity NPPV (HI-NPPV) with controlled NPPV and high inspiratory pressures 6.
- HI-NPPV has been shown to improve overnight blood gases, dyspnea, lung function, and disease-specific aspects of health-related quality of life, and may be superior to low-intensity NPPV (LI-NPPV) 6.