Non-Invasive Ventilation: BiPAP vs CPAP

Introduction

• NIV: Non-Invasive Ventilation
• NPPV: Non-Invasive Positive Pressure Ventilation
• Focus: BiPAP vs CPAP - understanding their roles in ventilation (removing CO2) and oxygenation (bringing in O2)

BiPAP (Bi-Level Positive Airway Pressure)

• Key Elements:
  • Two pressure settings: IPAP (Inspiratory Positive Airway Pressure) and EPAP (Expiratory Positive Airway Pressure)
  • Aids in both ventilation and oxygenation
• Mechanism:
  • Pressure gradient between EPAP and IPAP generates pressure support
  • Augments spontaneous tidal volume -> better CO2 removal and restoring normal pH balance
  • Pressure support overcomes airway resistance and enhances tidal volume

CPAP (Continuous Positive Airway Pressure)

• Key Elements:
  • One continuous baseline pressure
  • Aids only in oxygenation
• Mechanism:
  • Maintains a continuous baseline pressure that improves FRC (Functional Residual Capacity)
  • Increases volume by recruiting alveoli -> better oxygenation

Comparisons and Applications

• Pressure Support:
  • Difference between EPAP and IPAP in BiPAP is crucial for pressure support
• CPAP vs BiPAP:
  • CPAP: improves oxygenation by increasing FRC
  • BiPAP: addresses both ventilation and oxygenation issues
• PEEP (Positive End-Expiratory Pressure):
  • Similar in function to EPAP and CPAP, increases FRC and aids oxygenation

Blood Gas Analysis Scenarios

1. Scenario 1: Patient with oxygenation issue (e.g. PO2 of 52)
   • Solution: CPAP 8-12, if no ventilation issue
2. Scenario 2: Patient on BiPAP with ventilation problem
   • Solution: Increase IPAP to improve ventilation (e.g. from 10 to 15)
3. Scenario 3: Adjusting BiPAP for oxygenation problem
   • Solution: Increase EPAP while maintaining pressure support
4. Scenario 4: Patient with both ventilation and oxygenation problems
   • Solution: Adjust both IPAP for ventilation and EPAP for oxygenation

Important Takeaways

• IPAP vs EPAP: Not about the individual IPAP value alone, but the gradient between IPAP and EPAP that matters for effective ventilation
• Enhanced Tidal Volume: Pressure support is key to improving CO2 removal and restoring pH balance

Conclusion

• Key Message: Understand the difference and appropriate application of BiPAP and CPAP for effective patient care
• Advice: Don’t settle for average; strive for excellence in understanding and applying respiratory therapy concepts.