What is the management of hypercapnia in patients on BiPAP (Bilevel Positive Airway Pressure)?

From the Guidelines

Management of hypercapnia in patients on BiPAP should focus on adjusting the ventilatory settings to reduce PaCO2 levels, while also ensuring adequate oxygenation and monitoring for signs of respiratory acidosis.

Key Considerations

• The goal of BiPAP therapy in hypercapnic patients is to reduce PaCO2 levels and alleviate respiratory acidosis, as evidenced by the American Thoracic Society clinical practice guideline 1.
• High-intensity NIV, which involves high inspiratory pressures and higher-than-baseline respiratory rates, may be effective in reducing PaCO2 levels in patients with hypercapnic COPD 1.
• Oxygen therapy should be used judiciously in patients with COPD, as excessive oxygen use can worsen hypercapnia and respiratory acidosis, and a target oxygen saturation range of 88-92% is recommended 1.
• Non-invasive positive pressure ventilation, including BiPAP, can be effective in reducing respiratory distress and improving gas exchange in patients with hypercapnic respiratory failure, and should be considered in patients with a history of COPD or other risk factors for hypercapnic respiratory failure 1.
• Close monitoring of blood gases, pH, and oxygen saturation is essential to guide adjustments to BiPAP settings and oxygen therapy, and to prevent complications such as rebound hypoxaemia 1.

Adjusting BiPAP Settings

• The inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP) settings on the BiPAP device should be adjusted to optimize ventilation and reduce PaCO2 levels, with a goal of achieving a normal or near-normal PaCO2 level 1.
• The backup rate and inspiratory/expiratory time (IE) ratio should also be adjusted as needed to ensure adequate ventilation and prevent respiratory acidosis 1.

Oxygen Therapy

• Oxygen therapy should be titrated to maintain a target oxygen saturation range of 88-92% in patients with COPD, and to avoid excessive oxygen use that can worsen hypercapnia and respiratory acidosis 1.
• The use of a Venturi mask or nasal cannulae can help to deliver a precise amount of oxygen and minimize the risk of excessive oxygen use 1.

From the Research

Management of Hypercapnia in Patients on BiPAP

The management of hypercapnia in patients on BiPAP (Bilevel Positive Airway Pressure) involves several strategies, including:

• Adjusting the inspiratory and expiratory pressures to optimize ventilation and reduce carbon dioxide levels 2
• Using average volume assured pressure support (AVAPS) to automatically adjust to a patient's needs 2
• Monitoring arterial blood gases and adjusting the BiPAP settings accordingly 3, 4
• Considering the use of other modes of non-invasive ventilation, such as intelligent volume-assured pressure support (iVAPS) 5

Effectiveness of BiPAP in Hypercapnic Respiratory Failure

The effectiveness of BiPAP in hypercapnic respiratory failure has been studied in several trials, with results showing:

• BiPAP can improve gas exchange and reduce carbon dioxide levels in patients with chronic obstructive pulmonary disease (COPD) and hypercapnic encephalopathy 2
• BiPAP can reduce the need for endotracheal intubation and improve mortality rates in patients with acute hypercapnic respiratory failure due to non-COPD causes 3
• BiPAP can improve exercise tolerance and reduce dyspnea in patients with stable COPD 4

Comparison of BiPAP Modes

Several studies have compared the effectiveness of different BiPAP modes, including:

• BiPAP S/T (spontaneous/timed) vs AVAPS: AVAPS was found to be more effective in improving gas exchange and reducing carbon dioxide levels in patients with COPD and hypercapnic encephalopathy 2
• BiPAP S/T vs iVAPS: Both modes were found to be similarly effective in managing hypercapnic respiratory failure in patients with acute exacerbation of COPD 5