COMPLEX SLEEP APNEA IS IT A DISEASE? David Claman, MD UCSF Sleep Disorders Center

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1 COMPLEX SLEEP APNEA IS IT A DISEASE? David Claman, MD UCSF Sleep Disorders Center

2 CENTRAL APNEA Central Apnea Index > 5 ( >50% of apnea are central) Mayo Clinic Proc 1990; 65:1255

3 APNEA AT SLEEP ONSET

4 HYPERVENTILATION-INDUCED APNEA

5 LOOP GAIN AND VENTILATORY INSTABILITY Instability caused by: Phase delay between the effector portion of the system (the lungs) and the sensor for the system (CO2 detection in the carotid body and brainstem). Loop gain greater than 1 can promote instability. Loop gain can be mathematically defined as the response to a disturbance (hyperpnea) over the disturbance itself (apnea or hypopnea). If loop gain is less than 1, a respiratory disturbance will lead to a response, but it will be sufficiently small such that ventilation relatively quickly returns to a stable pattern. If loop gain is greater than 1, a respiratory disturbance will lead to such a large response that ventilation will wax and wane indefinitely. Thus, a high loop gain is destabilizing to ventilation both awake and asleep. CSR patients are typically hyper-responsive to CO2.

6 CHEYNE-STOKES Homogeneous in CHF Easier to Study!

7 Central Sleep Apnea Heterogeneous, Uncommon & Harder to Treat Hypercapneic Idiopathic central hypoventilation Neuromuscular disease Brainstem disease Non-Hypercapneic Idiopathic CSA Cheyne-Stokes with either CHF or Neurologic Ds High Altitude During Nasal CPAP (Complex Sleep Apnea) Opiates

8 CSA and Opiates (D Wang et al. CHEST 2005;128: ) 50 Methadone Maintenance pts + 20 Controls included in study 30% of Methadone group but 0% of controls had CSA index >5 events per hour on polysomnogram Obstructive AHI similar between groups CSA index was associated with Methadone serum concentration

9 COMPLEX SLEEP APNEA Complex sleep apnea is a form of sleep apnea identified by the emergence of central apnea during treatment with CPAP Medicare Guidelines 2006 recognize Complex Apnea as indication for Bi-level S/T In a recent clinical series in 1286 OSA pts, 6.5% had Complex Sleep Apnea at initial CPAP titration; majority of cases resolved over time: complex apnea only persisted in 1.5% at 8 weeks Javaheri S et al. J Clin Sleep Med 2009;5(3):

10 COMPLEX SLEEP APNEA Other causes of poor CPAP response Over-titration of CPAP Poor mask fit with excess leak Body weight changes requiring CPAP adjust True CPAP-emergent (Complex) sleep apnea Residual sleepiness on CPAP Co-existing depression or anxiety Narcotic use leading to central apnea Pro Con Debate: P Gay v A Malhotra; J Clin Sleep Med 2008; 4(5): and

11 ADAPTIVE PRESSURE SUPPORT SERVO-VENTILATION New bilevel S/T device developed for CSR After measuring minute ventilation for 3 minutes, delivers variable Pressure Support to achieve 90% of the average minute ventilation to reduce waxing / waning pattern Default EPAP 5 cm and back-up rate=15 can be adjusted

12 ADAPTIVE PRESSURE SUPPORT SERVO-VENTILATION Figure 2. Box plots of effect of treatment on central apnea index. Horizontal bar: median; thick vertical line: interquartile range; circles: outliers; thin bar: range excluding outliers. Also shown are statistical significance of comparisons between control and each of the four treatments, and between ASV and the other four conditions. Default Settings: EPAP 5 and back-up rate 15 **Teschler H, et al. Am J Respir Crit Care Med Aug 15;164(4):614-9

13 NPPV vs ASV for CSA & Complex Apnea (Morgenthaler SLEEP 2007;30(4): ) Crossover study of 21 subjects with either CSA or Complex sleep apnea to compare acute single night effects of NPPV vs ASV Results: both NPPV and ASV significantly reduced baseline AHI from range 46-51/hr; but ASV treatment had lower overall AHI=0.8 vs NPPV AHI=6.2 Limitation: no long-term data available

14 CONCLUSIONS Is Complex Apnea a disease? Based on Javaheri s data YES, initially 6.5% but only 1.5% persists in a large retrospective review Be diligent about other treatable issues! The majority of complex sleep apnea resolves over time For refractory complex apnea cases, Servoventilation, a form of bi-level S/T, is an appropriate treatment option