Can persistent obstructive events occur during PAP therapy from inadequate pressure, mask leak, or inconsistent use?

Persistent obstructive events on PAP matter because they may indicate incomplete control of upper-airway obstruction and can perpetuate the physiologic consequences PAP is intended to prevent.

Effectiveness and troubleshooting

• Inadequate pressure is a well-supported cause of persistent obstructive events. AASM titration targets control of obstructive events, preferably a respiratory disturbance index (RDI) <5/hour, with adequate oxygenation and acceptable leak. Telemonitoring observations indicate that predominantly obstructive residual events often resolve after pressure increases.
• Mask leak and inconsistent use are credible, actionable contributors. Leak warrants refitting, readjustment, and evaluation for mouth leak; time asleep without PAP leaves the underlying obstructive sleep apnea untreated. Neither a single device-reported residual AHI nor adherence summary alone identifies the mechanism.

Consequences of residual obstruction

• Persistent apneas/hypopneas can sustain intermittent hypoxia, since recurrent airflow limitation produces recurrent desaturation. In randomized evidence, effective CPAP normalized AHI alongside mean oxygen saturation and arousal index.
• Residual events can also maintain sleep fragmentation through event-related arousals, stage shifts, and increased light sleep. Systematic-review evidence finds CPAP more effective than nocturnal oxygen for reducing both sleep-disordered breathing and arousal-related disruption; improving oxygen saturation alone does not necessarily restore stable sleep.

Mechanistic and measurement considerations

• Substantial unintentional leak can make automated PAP event detection unreliable, so a device AHI may under- or mischaracterize residual disease.
• Leak may also promote central respiratory events. Thus, persistent device events should be differentiated into obstructive versus treatment-emergent central events, particularly when findings are discordant or unexplained.

Bottom line

• Persistent obstruction during PAP is most convincingly linked to insufficient pressure, while leak and inconsistent use remain important plausible contributors. For an 83-year-old man, review of nightly use, leak/flow data, pressure delivery, and event type—and laboratory reassessment when uncertainty persists—is important because uncontrolled events can continue both oxygen desaturation and fragmented sleep.