Persistent Leak and Mouth Breathing During a CPAP Titration
Mr. K, 58, BMI 38, is undergoing a full-night CPAP titration. At 01:10 he is on a nasal mask at 9 cmH2O. The leak channel reads 44 L/min, he is mouth-breathing with visible lip flutter, complaining of a dry mouth, and the flow signal shows variable flattening. Residual AHI since the last pressure change is 22/h, and SpO2 has dipped to 82% three times in the past 20 minutes. Your lab protocol allows the technologist to change pressure by 1 cmH2O no more often than every 5 minutes and to make minor interface adjustments; changing interface type requires a physician order.
1. What is the best next action, and why is raising the pressure the wrong move?
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The problem is interface leak and mouth leak, not under-titration. Raising pressure increases the trans-oral pressure gradient, so the mouth leak grows, the dry mouth worsens, and arousals increase - you would chase the leak upward and produce a worse night.
Sequence:
- Confirm the 44 L/min is real - check the leak sensor connection and whether the reading is machine-estimated or sensor-based.
- Re-seat and refit the mask; try a different cushion size; check headgear tension.
- Address the oral leak: chin strap if permitted by protocol, or a full-face/oronasal interface, which requires an order here.
- Check humidifier function and setting for the dry mouth.
- Reassess leak, flow, SpO2, and residual AHI after the fix before touching pressure.
Only after the leak is controlled does pressure titration data mean anything.
2. Where is the boundary of your scope of practice here, and what do you do at that boundary?
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Within scope under this protocol: pressure changes of 1 cmH2O no faster than every 5 minutes, minor adjustments, mask refitting, humidifier adjustments, and documenting it all.
Outside scope without an order: switching to an oronasal interface, and anything the protocol does not explicitly authorize.
At the boundary:
- Call the on-call physician or medical director, state the objective findings (leak 44 L/min, mouth breathing, SpO2 82% ×3, residual AHI 22/h at 9 cmH2O), and request the order.
- Document the time of the call, who you spoke with, the order received, and the time it was implemented.
- If no order is obtainable, continue within protocol, keep the study running, and document the limitation so the physician can interpret the titration knowing it was leak-limited.
- Never end the study or silently exceed the protocol.
3. Write the documentation you would want to see in the morning report for this 01:10 event.
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A useful entry answers: what did you see, what did you do, what happened, who did you tell.
Model entry:
- 01:10 - On nasal mask at 9 cmH2O; machine leak 44 L/min; audible/visible mouth leak; patient reports dry mouth; residual AHI 22/h since last change; three SpO2 dips to 82% in preceding 20 min.
- 01:15 - Leak sensor connection checked, intact. Mask re-seated, cushion changed, headgear retensioned. No pressure change made because the leak, not the pressure, was the limiting factor.
- 01:28 - Leak 12 L/min; mouth leak persists; chin strap applied per protocol.
- 01:35 - Physician called for oronasal interface order; order received; interface changed at 01:42; patient tolerated.
- 01:55 - Leak 8 L/min; residual AHI improving; SpO2 nadir 90%.
Include patient statements, tolerance, and the name of the physician contacted. This lets the interpreter see the titration was leak-limited, not pressure-refractory.