What is an acceptable leak rate on a Bi-Level Positive Airway Pressure (BPAP) device, specifically the Luna BPAP?

Acceptable Leak Rates on a Luna BPAP Device

An acceptable leak for a Luna BPAP device is one that is not substantially higher than the leak recorded at a given pressure from a well-fitted, applied, and secured interface, with the understanding that the acceptable leak will always exceed the intentional leak specified by the manufacturer for the particular mask interface being used. 1

Understanding Leak Types and Significance

• Leaks in BPAP therapy occur in two forms:

  • Intentional leak: The controlled leak from ports on mask interfaces designed to wash out CO2 and prevent rebreathing 1
  • Unintentional leak: Either "mouth leak" (air escaping via mouth when using nasal mask) or "mask leak" (air escaping between mask and face) 1

• The total leak is the sum of intentional and unintentional leaks, and varies based on:

  • Applied pressure (higher pressures create more leak) 1
  • Interface type (different masks have different intentional leak designs) 1
  • Mask fit quality 1

Determining Acceptable vs. Unacceptable Leak

• There is insufficient evidence for specific numerical values that constitute a clinically significant leak 1

• An unacceptable leak is generally defined as one that:

  • Is substantially higher than the leak recorded at a given pressure from a well-fitted mask 1
  • Causes significant symptoms such as arousals during sleep 1
  • Prevents effective therapy by reducing the ability of pressure support to augment tidal volume 1
  • Interferes with achieving treatment goals (RDI <5/hour, SpO2 >90%, absence of snoring) 1

• Monitoring leak trends is often more informative than absolute values:

  • A sudden increase in leak without pressure changes suggests increased unintentional leak 1
  • Higher leak levels are associated with poor adherence to therapy 2

Clinical Impact of Excessive Leak

• Excessive unintentional leak can:
  • Reduce the effectiveness of BPAP therapy 1
  • Cause decreased oxygenation and increased arousal index 1
  • Reduce REM sleep quality 1
  • Lead to poor adherence to therapy 2
  • Cause the device to underestimate required pressure and overestimate delivered pressure 3

Managing Leak Issues

• Mask refit or readjustment should be performed whenever significant unintentional leak is observed 1

• For mouth leak with nasal mask:

  • Add a chinstrap to reduce mouth opening 1
  • Consider switching to a full-face/oronasal mask 1

• For mask leak:

  • Adjust mask fit and tension 1
  • Consider trying a different mask type 1

• Be aware that some BPAP devices have better leak compensation capabilities than others 4

Monitoring and Assessment

• Refer to the Luna BPAP manufacturer's specifications for the intentional leak vs. pressure relationship for your specific interface 1

• Use clinical judgment based on:

  • Laboratory-specific criteria 1
  • Manufacturer's specifications 1
  • Patient symptoms and therapy effectiveness 1
  • Device-reported leak data trends rather than isolated readings 1

• A good titration should achieve:

  • RDI ≤10 per hour (or reduced by at least 50% if baseline RDI <15) 1
  • Minimum SpO2 above 90% 1
  • Leak within acceptable parameters as defined above 1