CPAP
vs
What Every Clinician Needs to Know
Carol Ash, DO, MBA, FAASM
Corporate Director of Sleep Medicine
Meridian Health New Jersey
CPAP vs APAP
• What are the different device options
• Understand the operational differences between the two modalities
• Separate the myth from the reality
• What factors to consider when deciding
• Understand unique APAP algorithms for identifying and responding to
respiratory events
• What the studies recommend
• What is the future direction
History Positive Airway Pressure (PAP) Devices
• Introduced in 1953 by Dr. Bjorn Ibsen, an anesthesiologist during
Copenhagen’s polio epidemic, which saw the birth of intensive care
• 1981 Dr. Colin Sullivan introduces the noninvasive application of
positive airway pressure to treat obstructive sleep apnea (OSA) with
the nifty invention of a reversed vacuum machine
Dr. Bjorn Ibsen
Dr. Colin Sullivan
What’s In A Name?
• PAP – Positive Airway Pressure
• CPAP – Continuous Airway Pressure
• Bi-level (BIPAP)
• APAP - Auto-titrating PAP (auto-PAP)
• ASV - Adaptive Servo-Ventilation
PAP Insurance
CPAP will be covered for adults with sleep-disordered breathing if:
• AHI (or RDI) > 15
OR
• AHI (or RDI) > 5 with (“mild, symptomatic”)
• Hypertension
• Stroke
• Sleepiness
• Ischemic heart disease
• Insomnia
• Mood disorders
Physiology of PAP
• Works to splint the airway open and prevent the collapse of the upper
airway
• Greater end-expiratory lung volume and increase in oxygen stores
• Increased tracheal traction to improve upper airway patency
• Lower cardiac after- load and consequent increase in cardiac output
• Decrease venous return
• Cost-effective and one least toxic forms of medical therapy
Negative Consequences PAP
• Increase abdominal muscle effort
• Provoke anxiety
• Cause central apneas by destabilizing breathing
• May eliminate CO2 and reduce arterial PCO2 below the apnea
threshold
• Ventilatory instability characterized by central apneas and periodic breathing.
• Mask interface-related skin changes (abrasions, pressure sores,
contact dermatitis)
• Aerophagia, sinus pain, oral/nasal dryness, tooth decay
CPAP vs APAP
• CPAP continuous pressure set during titration during in house sleep
study or best guess standard treatment OSA
• APAP devices change the treatment pressure based on feedback from
various patient measures such as airflow, pressure fluctuations, or
measures of airway resistance
CPAP
• Constant between inspiration and expiration
• Achieved by a servo-controlled air compressor maintains the airway
pressure as closely to the prescribed pressure despite the pull
(inspiration) and push (exhalation)
• Within an FDA-specified pressure range (for example, ± 1.5 cm H2O of
the set pressure) as a quality-assurance measure
• Error range is generally greater with larger tidal volume (VT) or inspiratory
effort from patient, faster respiratory rate, and at higher RX set pressure
• Allows response to changes in the airway pressure
Auto-titrating PAP (APAP, auto-PAP)
• Built in microprocessors detect and treat OSA
• Self-adjusting, automatic, auto-adjusting, smart CPAP and autotitrating PAP (auto-PAP).
• Purposes:
• Alternative to in-laboratory manual titration
• Achieve lower mean pressures, promote adherence
• Allows PAP changes in response to changes in:
• Severity of OSA , weight, sleep state, body position, alcohol use
• Expanded to detecting SDB, treating central apneas, and
correcting hypoventilation
APAP pressure
changes based
on a patient’s needs
at a specific time
CPAP pressure is
maintained at a
constant, generally
based on a patient’s
In-lab titration
APAP
• Aid in the pressure titration process
• Address possible changes in pressure requirements throughout a
given night and from night to night
• Aid in treatment of OSA when attended CPAP titration has not or
cannot be accomplished
• Improve patient comfort
AASM Current APAP
Recommendations
• Not recommended to:
• Diagnose OSA
• Facilitate split night titration (certain devices can be used during attended)
• Treat:
• CHF
• Significant lung disease (COPD)
• Nocturnal arterial oxyhemoglobin desaturation due to conditions other
than OSA (e.g. OHS)
• Patients who do not snore (includes post palate surgery)
• Central sleep apnea syndromes
APAP Device Technology
• First generation sensors merely measured pressure vibrations that
were caused by snoring
• Next generation able to sense flow-based changes (apnea, hypopnea,
or inspiratory flow limitation) based upon the inspiratory flow
contour (ie, flattening of the inspiratory flow waveform)
Newer Generation Devices
• Can differentiate central from obstructive apneas
• Uses forced oscillation technique / measures compliance changes
• Identify Cheyne-Stokes respiration - detects variation peak flow
• Identify hypoventilation – measures VT or V̇E using calibrated flow
sensors
• Compensates for air leaks - using sophisticated flow-based
algorithms
• Measure upper and lower airway resistance - using forced
oscillation techniques
APAP Titration for Moderate to Severe OSA
• Can be used to identify a single CPAP pressure
• Self-adjusting mode for unattended titration and treatment without
comorbidities (CHF, COPD, central sleep apnea syndromes, or
hypoventilation syndromes)
• When used in titration to set fixed CPAP or being treated with APAP
must have close clinical follow-up for effectiveness and safety
• Symptoms remain - Reevaluate, Standard attended CPAP titration if
symptoms do not resolve or APAP lacks efficacy
APAP
• Intended to be long-term solutions
• Is designed to adjust with patients as their condition and physiology
fluctuate.
• APAP adjusts proactively verses reactively
• Auto Set responds to three separate parameters, based on the degree
of airway blockage: inspiratory flow limitation, snore, and apnea.
Bench Studies & RCTs
• Responses of devices from different manufacturers are quite varied
• Air leak affected the performance
• Some devices were more resilient
• Implications of the effects of air leak
• RCT avoided comorbid conditions
CPAP
APAP
• Equivalent Control of AHI
• At a lower mean pressure
• Improving sleep stage distribution and providing comparable
improvements in daytime sleepiness
• Patients clear preference toward APAP devices and demonstrated
marginally improved compliance
Coughlin
CPAP
APAP
• Both require follow-up with patients to address issues like mask fit,
compliance, and humidity
• Clinically validated algorithms to ensure adequate treatment
• Flow limitation is a precursor to other more severe sleep-disordered
breathing events. An AutoCPAP needs to be able to respond to these
flow-limited events in a timely manner to ensure that the more
severe sleep-disordered breathing events (apnea and hypopnea) are
minimized.”
• Now differentiation between APAP solutions for OSA vs CSA
CPAP
APAP
• Sleepiness
• Twenty-four trials that included over 1,000 patients provided
evidence that APAP reduces sleepiness as measured by ESS by
approximately 0.5 points more than fixed CPAP. For compliance,
there was a statistically significant difference of 11 minutes per
night also favoring APAP compared to fixed CPAP.
Recommendations
• If patients are carefully selected, auto-PAP-derived optimal CPAP
pressure compares favorably to PSG-derived CPAP determinations
• Exclude comorbidities (CHF, COPD, CSA, hypoventilation syndromes)
from such treatment strategies
• Auto-PAP therapy may provide cost savings
• Formal cost-effectiveness studies need to be performed with RCTs or across
healthcare system databases.
• Comparative-effectiveness of auto-PAP and PSG-based management
strategies requires further study.
Adaptive Servo-Ventilation (ASV) for
CSAS
• Practice Parameter 2012 Standard: ASV targeted to normalize the AHI
is indicated for the treatment of CSAS related to CHF
• Field Safety Notice issued by ResMed May 2015
• AASM advised physicians to stop prescribing ASV
• To treat central sleep apnea
• Symptomatic heart failure with LVEF <45%.
Adaptive Servo-Ventilation (ASV) for CSAS
FMCSA
• Gives little guidance to Medical Examiner
• HST to APAP acceptable for treatment, and compliance monitoring
• Needs to meet EBM for clinical quality and safety
What Is Ahead?
• Smaller devices
• Convenient battery backup work on one charge for days
• Smaller lighter humidifiers
• Incorporation of a technology that doesn’t require daily patientinitiated water changes
• Easier ability to clean, sterilize, and maintain the device accordingly
• Routine sleep screenings as a preventative therapy
• Smarter algorithms and sensor features
• The “on button” - care delivery is changing for everyone
Sleep Health Prevention
•
Conclusion…
EBM – Go by the book, rest assured.
Questions?