When should a patient be switched from Continuous Positive Airway Pressure (CPAP) to Bilevel Positive Airway Pressure (BiPAP)?

Indications for Switching from CPAP to BiPAP in OSA Patients

BiPAP should be used when patients fail CPAP therapy due to pressure intolerance, persistent symptoms, or comorbid conditions requiring ventilatory support, rather than as routine first-line therapy for OSA. 1

Primary Indications for Switching to BiPAP

The American Academy of Sleep Medicine (AASM) provides clear guidance on when to consider transitioning a patient from CPAP to BiPAP:

1. Pressure intolerance issues:

   • Patients who cannot tolerate high expiratory pressures required for effective CPAP therapy 1, 2
   • When CPAP pressures exceed 15-16 cm H₂O and cause discomfort 2

2. Persistent OSA symptoms despite adequate CPAP use:

   • Uncontrolled symptoms despite compliance with CPAP therapy 2
   • Residual apneas or hypopneas on CPAP 1

3. Comorbid conditions requiring ventilatory support:

   • Neuromuscular disorders 1
   • Chest wall deformities 1
   • Central sleep apnea or mixed sleep apnea 1, 3
   • Cheyne-Stokes breathing patterns 1
   • Obesity hypoventilation syndrome 2
   • COPD or other respiratory comorbidities affecting nocturnal breathing 2

4. CPAP-related side effects:

   • Persistent mouth dryness, choking sensation, or aerophagia 4
   • Mask-related problems that cannot be resolved with CPAP 2
   • Claustrophobia that interferes with CPAP use 2

Benefits of Switching to BiPAP

Research demonstrates several advantages when appropriate patients are switched from CPAP to BiPAP:

• Lower expiratory pressures can be used (typically 8-10 cm H₂O) while maintaining therapeutic inspiratory pressures 2, 4
• Improved adherence to therapy (average increase from 2.5 to 7.0 hours/night in one study) 2
• Better symptom control and reduced daytime sleepiness 2, 4
• Significant improvements in sleep quality as measured by standardized indices 4
• Reduction in CPAP-related side effects like mouth dryness and aerophagia 4
• High patient preference (90% preferred BiPAP over CPAP in one study) 4

Initial BiPAP Settings and Adjustments

When transitioning a patient to BiPAP, the AASM recommends these initial settings:

• IPAP (inspiratory pressure): Start at 8 cm H₂O, increase in 1-2 cm H₂O increments as needed 1
• EPAP (expiratory pressure): Start at 4 cm H₂O, increase in 1 cm H₂O increments as needed 1
• Maintain a minimum IPAP-EPAP differential of 4 cm H₂O 1
• Maximum IPAP-EPAP differential should not exceed 10 cm H₂O 1
• Maximum IPAP is 30 cm H₂O for adults (20 cm H₂O for children) 1
• Maximum EPAP is typically 8-10 cm H₂O, adjusted based on patient tolerance 1

Contraindications and Precautions

BiPAP therapy is contraindicated in certain situations:

• Respiratory arrest 1
• Inability to protect airway 1
• Severe facial trauma or burns 1
• Recent facial, esophageal, or gastric surgery 1
• Active hemoptysis (particularly massive hemoptysis) 5

Special precautions should be taken in patients with:

• Hemodynamic instability 1
• Copious secretions 1
• Risk of vomiting 1
• Severe agitation or uncooperative behavior 1

Clinical Pearls and Pitfalls

• Common pitfall: Using BiPAP as first-line therapy for all OSA patients. The AASM suggests using CPAP or APAP over BiPAP for routine OSA treatment 1
• Important consideration: Mask leaks can compromise BiPAP effectiveness; refit or change mask type when significant leaks occur 1
• Monitoring: After switching to BiPAP, monitor residual AHI, device usage, and symptom improvement to ensure therapy effectiveness 2, 4
• Patient education: Educational interventions at BiPAP initiation are strongly recommended to improve adherence 1
• Follow-up: Ensure adequate follow-up, including troubleshooting and monitoring of objective efficacy and usage data 1