Central Sleep Apnea in Adults: Causes and Treatment

Timothy Daum MD

Spectrum Health

Grand Rapids

Rogers, R. Chest 2008;133:598

The majority of sleep apnea we see is obstructive in nature:

Central Sleep Apnea

• At most 10% of sleep study population

• Pathogenesis– Distinguishing characteristics

• Approach to management

Central Sleep Apnea• Sleep transition central apnea• Congenital Alveolar Hypoventilation

– Ondine’s Curse

• CHF– Cheyne-Stokes Periodic Breathing

• Stroke or Other Neurologic Insult• High Altitude Periodic Breathing• Narcotics• Treatment Emergent Central Apnea• Complex Sleep Disordered Breathing

CSA: Symptoms

• Disrupted, unrefreshing sleep

• Many complain of insomnia

• Excessive daytime sleepiness

Sleep Transition Central Apnea

• Common with recurrent arousals– OSA, PLMS

• CO2 will climb from 40 to 45 in normal sleep

• Robust ventilatory response with arousal

• CO2 driven below ventilatory threshold

• Apnea with sleep onset

Sleep Transition Central Apnea

Sleep Transition Related Central Apnea

Congenital Alveolar Hypoventilation

• Ondine’s curse• Due to recently recognized genetic

abnormality• Affected individuals have higher CO2 set

point• Usually identified in infants

– Milder cases found in adults

• Responds well to timed Bilevel Pressure

CSA and CHF

• Up to 40% of those with reduced LVEF

• Most common with:– More advanced age– Male– Atrial fibrillation

• Presence of CSA portends a worse prognosis

SDB in CHF Patients

OSA

CSA

Level IVLevel IIILevel IILevel I

Mixed Apneas

New York Heart Association

CSA and CHF:Cheyne-Stokes Periodic Breathing

• Note period length of 60-90 sec• Note circulation time. Usually over 30 seconds in CHF.

CHF and CSA: Pathogenesis

• Dyspnea leads to hyperventilation and hypocapnea while awake

• With sleep onset, hypocapnea leads to apnea and hypoventilation

• With increased circulation time, hypercapnea becomes significant before blood gets from lungs to brain stem leading to marked hyperventilation

• Hyperventilation leads to hypocapnea• Repeat

CHF and CSA: Treatment

• Main therapy is optimize medical management of CHF

• Positive airway pressure shown to:– Improve exercise tolerance– Improve LVEF– Decrease catecholamines– Quality of Life

• No proven benefit on mortality

CHF and CSA: Alternative Treatments

• Oxygen – May decrease dyspnea and hyperventilation

• Theophylline– Respiratory stimulant

• Adaptive Servo Ventilation

CSA and CVA

• Present in 26% of acute stroke patients

• Continues in 7% long term

• Remember the high incidence of OSA in stroke patients as well– Unclear if this precedes CVA

CSA and Narcotics

• Can be seen in up to 50% of chronic narcotic users.• Prevalence almost certainly increasing.

Treatment Emergent Central Apnea

• Titration of CPAP beyond that needed to resolve obstructive events can lead to the development of central events with arousals.

• Important to differentiate from complex sleep apnea– Central events seen before obstructive events

controlled

Complex Sleep Disordered Breathing

• Traditional classification is obstructive vs central sleep apnea

• Recently recognized group of patients who start out looking like mostly OSA but develop prominent CSA with CPAP

• Central apneas develop before obstructive events controlled

Complex SDB: Baseline

Complex SDB: CPAP

What Do We Know About CompSA?

• Prevalence: Estimated to be 15% of SDB population

• About 50% don’t ever respond to CPAP – Residual symptoms (fatigue, sleepiness, depression)– Intolerance to therapy

• Dramatic improvement during REM sleep (reverse of pattern seen in OSA)

• No distinguishing clinical profile

Morgenthaler et al, Sleep, 2006

CSA: Treatment

CSA: Treatment

• Maximize medical therapy of underlying condition– Diuretics; afterload reduction; beta-blockers,

biventricular pacers for CHF– Minimize narcotics and other sedatives

• Trial CPAP– Often unresponsive

Adaptive Servo Ventilation

• Servo: Any type of self-regulating feedback system or mechanism

• VPAP Adapt SV– ResMed

• BiPAP auto SV– Respironics

PAP Therapy

™

How Does it Work?

• Creates a Target Ventilation– The ASV algorithm monitors recent average minute

ventilation (~3 min window)– It continuously calculates a target ventilation

throughout the night (90% of recent average ventilation)

• Ventilates to the Target– Algorithm monitors patient ventilation and compares it

to the target ventilation– Adjusts pressure support up or down as needed to

achieve target

End Expiratory Pressure (EEP)

• EEP = EPAP

• Default EEP = 5 cm H20– May adjust in 1-2 cm increments to resolve any upper airway

obstruction (for CHF patients wait 40 minutes before adjusting)

EEP: manually titrate like CPAP to hold airway patent

Time

Pressure (cm H20)

Pressure Support (PS)

• Pressure support = IPAP - EPAP

• Pressure support varies between limits

– minPS (default 3 cm H2O)

– maxPS (default 10 cm H2O)

• Values are adjustable but defaults work in almost all cases

maxPS

Time

Pressure (cm H20) minPS

Gives Support Only When Needed

The ASV algorithm automatically adjusts the magnitude of pressure support breath by breath to:

– Provide minimal, comfortable support during the over-breathing phase (hyperpnea) or during normal breathing

– Increase support during under-breathing(hypopnea or apnea)

Time

Pressure (cm H20)

Central apnea(no spontaneous effort)

Normalbreathing effort

Support When Needed

Effort

Flow

SpO2

FG

Normalized Breathing: 10 Minutes Into Session

Effort

Flow

SpO2

FG

Greatest Reduction in Central Apnea Index

• 83% further reduction in CAI compared to CPAP

• 50% reduction compared to bilevel

Teschler et al, AJRCCM, 2001

Normalizes Total Arousal Index

• Partial improvement with oxygen and CPAP

• Normalization with bilevel and ACS

Teschler et al, AJRCCM, 2001

Significant Increase in Deep Sleep

• SWS+REM = % time spent in deep, restorative sleep

• Large increases in SWS+REM with ASV and bilevel but not with either O2 or CPAP

Teschler et al, AJRCCM, 2001

CMS Guidelines for CSA(E0471)

Conclusion

• By now, you should be able to:– List the ideal types of patients for VPAP Adapt SV

– Describe how the VPAP Adapt SV treats patients

– Discuss the results of studies using ResMed’s Adaptive Servo-Ventilation algorithm

– List the keys to successful treatment

– State the qualifying criteria and reimbursement guidelines for the VPAP Adapt SV