Maximum Oxygen Bleed for ResMed BiPAP Devices
The maximum oxygen bleed that can be safely used with a ResMed BiPAP device is typically 10-15 L/min, though this should be carefully monitored as higher pressure settings will reduce the effective oxygen concentration delivered to the patient. 1
Factors Affecting Oxygen Delivery in BiPAP
Oxygen Delivery Principles
- Oxygen can be added to BiPAP circuits through a T-connector between the device outlet and the hose, allowing supplemental oxygen to enter through the side arm 1
- The effective fraction of inspired oxygen (FiO₂) for a given supplemental oxygen flow rate decreases as IPAP or EPAP pressures increase due to increased intentional leak 1
- FiO₂ does not appear to vary with the amount of pressure support or respiratory rate 1
Optimal Oxygen Administration
- Oxygen should be connected to the PAP device outlet using a T-connector for optimal mixing and to provide a reservoir of enriched gas 1
- Delivered oxygen concentration is affected by:
- Type of leak port
- Site of oxygen injection
- Ventilator pressure settings
- Oxygen flow rate 2
Oxygen Titration Guidelines
Starting and Adjusting Oxygen
- Supplemental oxygen should be initiated at 1 L/min for both pediatric and adult patients 1
- Oxygen flow should be increased by 1 L/min at intervals no shorter than 15 minutes until SpO₂ is between 88% and 94% 1
- A slightly higher SpO₂ goal of 90-94% might be prudent in some circumstances due to potential overestimation by pulse oximetry 1
When to Add Oxygen
- Supplemental oxygen should be added when:
- Patient's awake supine SpO₂ is ≤88% while breathing room air
- SpO₂ is ≤88% for ≥5 minutes during titration in the absence of obstructive respiratory events 1
Pressure Settings and Oxygen Interaction
Impact of Pressure on Oxygen Delivery
- Higher IPAP and EPAP settings reduce the effective oxygen concentration for a given flow rate 1, 2
- The highest oxygen concentration is achieved with lower pressure settings (e.g., IPAP 10 cm H₂O, EPAP 5 cm H₂O) 2
Pressure Recommendations
- Recommended minimum starting IPAP and EPAP should be 8 cm H₂O and 4 cm H₂O respectively 1
- Maximum IPAP should be 30 cm H₂O for patients ≥12 years and 20 cm H₂O for patients <12 years 1
- Minimum pressure support (difference between IPAP and EPAP) should be 4 cm H₂O 1
Monitoring and Safety Considerations
Continuous Monitoring
- Continuous SpO₂ monitoring via pulse oximetry is essential for patients receiving oxygen supplementation with BiPAP 2
- Delivered oxygen concentration is a complex interaction between multiple factors, making monitoring critical 2
Potential Complications
- Carbon dioxide rebreathing can occur with standard BiPAP systems, which may be prevented by using a non-rebreathing valve 3
- Higher pressure settings may cause patient discomfort and reduce adherence 1
- If the patient awakens and complains of pressure discomfort, pressures should be decreased to a level that allows return to sleep 1
Clinical Applications
- BiPAP with supplemental oxygen has been successfully used for various respiratory conditions including COPD exacerbations, cardiogenic pulmonary edema, and pneumonia 4, 5
- In carefully selected patients with respiratory distress, BiPAP ventilation with appropriate oxygen supplementation may help avoid endotracheal intubation 5