Complex/Mixed Sleep Apnea
A combination of obstructive and central sleep apnea, where patients have both airway obstruction and brain signaling issues affecting breathing during sleep.
What is Complex/Mixed Sleep Apnea?
Complex sleep apnea, also known as treatment-emergent central sleep apnea, is a form of sleep-disordered breathing that combines features of both obstructive sleep apnea (OSA) and central sleep apnea (CSA). In this condition, patients initially present with obstructive sleep apnea, but when treated with CPAP therapy, central apneas emerge or persist even after the obstructive events are resolved. Mixed sleep apnea refers to single apnea events that begin as central apneas but end with an obstructive component. Both conditions require specialized treatment approaches.
Prevalence
Complex sleep apnea affects approximately 5-15% of patients with obstructive sleep apnea who are started on CPAP therapy. The condition is more common in men, patients with coronary artery disease, and those with more severe OSA.
Causes
The exact mechanism is not fully understood. In complex sleep apnea, it appears that treating the obstructive component unmasks an underlying central breathing instability. Contributing factors may include unstable ventilatory control, heart failure, opioid use, and individual variation in how the brain responds to changes in carbon dioxide levels during sleep.
Symptoms
Persistent symptoms despite CPAP use
Patients may continue to experience poor sleep, fatigue, and daytime sleepiness even with consistent CPAP use that appears to be eliminating obstructive events.
Observed breathing pauses
Bed partners may notice that breathing pauses continue even while the patient is using their CPAP machine.
CPAP intolerance
Patients may report that CPAP feels uncomfortable or that they feel like they're fighting against the machine, possibly due to central apneas.
Excessive daytime sleepiness
Despite adequate CPAP pressure and usage, patients remain excessively tired during the day.
Morning headaches
Headaches upon waking may persist due to continued oxygen desaturation from central apneas.
Fragmented sleep
Frequent awakenings throughout the night as the brain responds to repeated apnea events.
Diagnosis
Self-Assessment Questions
If you answer yes to any of these questions, consider consulting a sleep specialist:
- 1Have you been using CPAP for OSA but still feel unrefreshed and tired?
- 2Does your CPAP data show that you still have apnea events despite using the device?
- 3Have you been told your breathing pauses look different from typical snoring-related apneas?
- 4Do you have heart disease or use opioid medications?
- 5Do you feel like you're fighting against your CPAP when trying to breathe?
Diagnosis typically occurs during CPAP titration studies when central apneas are observed to emerge or persist despite elimination of obstructive events. A comprehensive polysomnography is essential for accurate diagnosis.
Polysomnography with CPAP Titration
An overnight sleep study where CPAP pressure is adjusted while monitoring reveals the emergence of central apneas as obstructive events are resolved.
CPAP Download Analysis
Reviewing data from the patient's CPAP machine can show persistent apnea events with patterns suggestive of central rather than obstructive apneas.
Cardiac Evaluation
Assessment for underlying heart conditions that may contribute to central apneas, including echocardiogram and possibly cardiac catheterization.
Treatment
Treatment aims to address both the obstructive and central components of the disorder. Often, a trial period with CPAP is recommended first, as some central apneas resolve spontaneously within weeks to months.
Continued CPAP Trial
In many patients, treatment-emergent central apneas resolve within 1-3 months of continued CPAP use. Patience and monitoring are recommended before switching therapies.
Adaptive Servo-Ventilation (ASV)
The preferred treatment for complex sleep apnea when central apneas persist. ASV dynamically adjusts pressure support breath-by-breath to stabilize breathing. Note: ASV is contraindicated in heart failure patients with reduced ejection fraction.
BiPAP with Backup Rate
Bilevel positive airway pressure with a set backup respiratory rate can ensure minimum breathing is maintained during central apnea events.
CPAP Pressure Adjustment
Sometimes lowering CPAP pressure can reduce central apneas while still treating obstructive events, though this requires careful balance.
Treat Underlying Conditions
Managing heart failure, adjusting opioid medications, or treating other contributing conditions can help resolve central apneas.
Lifestyle Adjustments
- •Maintain consistent use of prescribed therapy even if initial response seems poor
- •Avoid alcohol and sedative medications
- •Maintain a healthy weight
- •Follow heart-healthy lifestyle practices
- •Keep regular follow-up appointments to monitor therapy response
- •Report any medication changes to your sleep specialist
Find a Specialist
Search our directory for sleep clinics that specialize in treating complex/mixed sleep apnea.
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