Subject Characteristics

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Positive Airway Pressure For OSAS BYAHMAD
YOUNESPROFESSOR OF THORACIC MEDICINE Mansoura
Faculty Of Medicine
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International classification of sleep disorders,
criteria for OSA Diagnosis A B D or C D

• A. At least one of the following applies
• i. Complaints of unintentional sleep episodes
  during wakefulness, daytime sleepiness,
  un-refreshing sleep , fatigue, or insomnia.
• ii. Awakenings with breath-holding, gasping, or
  choking.
• iii. Bed partner reports loud snoring and/or
  breathing interruptions during the patients
  sleep.
• B. Polysomnography shows the following
• i. Scoreable respiratory events (apneas
  hypopneas RERAs)/hr of sleep 5/hr.
• ii. Evidence of respiratory effort during all or
  a portion of each respiratory event.

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International classification of sleep disorders,
criteria for OSA Diagnosis A B D or C D

• C. Polysomnography shows the following
• i. Scoreable respiratory events (apneas
  hypopneas RERAs)/hr of sleep 15/hr.
• ii. Evidence of respiratory effort during all or
  a portion of each respiratory event.
• D. The disorder is not better explained by
  another current sleep disorder, medical or
  neurologic disorder, medication use, or substance
  use disorder.

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Positive Airway Pressure Therapy

• Administration of positive airway pressure
  therapy is the treatment of choice for most
  patients with OSA.
• CPAP treatment is generally recommended for all
  patients with an AHI greater than or equal to
  15/hour and for symptomatic patients (eg,
  excessive daytime sleepiness, insomnia, impaired
  cognition, mood disorder, hypertension, ischemic
  heart disease, or stroke) with an AHI between
  515/hour.

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Treatment modalities for Positive Airway Pressure
Therapy

• Continuous positive airway pressure Provides a
  constant pressure throughout the respiratory
  cycle
• Bi-level positive airway pressure Provides two
  pressure levels during the respiratory cycle a
  higher level during inspiration and a lower
  pressure during expiration
• Autotitrating positive airway pressure Provides
  variable pressures using device-specific
  diagnostic and therapeutic algorithms
• Nocturnal noninvasive positive pressure
  ventilation Provides two pressure levels at a set
  rate to assist ventilation

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Determining Optimal Continuous Positive Airway
Pressure

• 1. In-laboratory attended polysomnographically
  guided CPAP titration
• Full-night studies.
• Split-night studies (consists of an initial
  diagnostic portion and a subsequent CPAP
  titration on the same night)
• 2. Unattended laboratory or home titration
• 3. Use of autotitrating devices
• 4. Formula-derived pressures from clinical, PSG,
  and/or anthropometric variables

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The current standard of practice

• The current standard of practice involves an
  attended pressure titration during a laboratory
  PSG, during which sleep stages and respiratory
  variables are monitored.
• The goal is to determine a single fixed pressure
  that eliminates apneas, hypopneas, snoring, and
  respiratory effortrelated arousals (RERAs)
  maintains adequate oxygen saturation and
  improves sleep architecture and quality in all
  sleep positions and in all sleep stages.
• It is generally accepted that higher pressures
  are required to reverse airway occlusion during
  REM sleep and during sleep in a supine position.
• Spit-night studies can potentially underestimate
  the severity of OSA

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Criteria for split-night (CPAP) titration

• At least 2 hours of recorded sleep time during
  the initial diagnostic portion of the study
• Apnea-hypopnea indices during the diagnostic
  portion of the study AHI 40 OR
• AHI ?2040 (accompanied by significant oxygen
  desaturation)
• At least 3 hours are available for CPAP titration
  with the presence of REM sleep during a supine
  sleep position

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AASM recommendations for CPAP and BPAP therapy
for adult patients with sleep related breathing
disorders

• The presence of OSA based on an acceptable
  diagnostic method should be established prior to
  CPAP therapy (standard).
• Indications for CPAP therapy include
• a. Moderate to severe OSA (standard)
• b. Mild OSA (option)
• c. Improvement of subjective sleepiness in
  patients with OSA (standard)
• d. Improvement of quality of life in patients
  with OSA (option)
• e. As an adjunctive therapy to lower blood
  pressure in patients with OSA (option)

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AASM recommendations for CPAP and BPAP therapy
for adult patients with sleep related breathing
disorders

• 3. The preferred CPAP titration method to
  determine optimal positive airway pressure is an
  in-laboratory, full-night, attended
  polysomnography, but split-night studies are
  usually adequate (guideline).
• 4. Objective monitoring of CPAP use is
  recommended to ensure optimal utilization
  (standard).
• 5. Close monitoring of CPAP utilization and any
  problems that might develop, especially during
  the first few weeks of use, is important, as is
  the correction of problems if needed (standard).
• 6. Addition of heated humidification and a
  systematic educational program enhance adherence
  to CPAP use (standard).

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AASM recommendations for CPAP and BPAP therapy
for adult patients with sleep related breathing
disorders

• 7. Patients with OSA treated with CPAP therapy
  should be followed up yearly or more frequently
  as needed to correct problems related to its use
  (option).
• 8. CPAP and bilevel positive airway pressure
  (BPAP) therapy are generally safe with minor
  adverse effects (standard).
• 9. BPAP can be considered as an optional therapy
  to CPAP in selected patients who require high
  pressures, who report difficulty exhaling against
  a fixed CPAP pressure, or who have coexisting
  central hypoventilation (guideline).
• 10. BPAP may also be beneficial in patients with
  some forms of restrictive lung disease or
  hypoventilation syndromes with daytime
  hypercapnia (option).

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AASM recommendations for CPAP and BPAP therapy
for adult patients with sleep related breathing
disorders

• The extent to which asymptomatic patients with
  mild OSA and no associated medical or psychiatric
  disorders benefit from CPAP is less certain.
• Intermittent use of CPAP should be avoided,
  because virtually all of the gains in sleep
  quality and daytime alertness derived from
  sleeping with CPAP are rapidly reversed with CPAP
  discontinuation.

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Starting PAP treatment based on a prediction
equation with subsequent adjustment based on
symptoms, machine readings, and nocturnal
oximetry.

• Predicted CPAP 0.16XBMI 0.13 X NC 0.04 XAHI
  5.12
• where BMI body mass index and NC neck
  circumference in centimeters AHI apnea hypopnea
  index.

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Beneficial effects of positive airway pressure
therapy in OSA

• Sleep quality Improvement in sleep quality
• Upper airway anatomy and function
• Reduction or elimination of snoring
• Decrease in apneahypopnea index (AHI)
• Increase in arterial oxygen saturation (SaO2)
• Sleepiness and other daytime symptoms
• Decrease in sleepiness (subjective and objective)
• Improvement in quality of life
• Enhancement of mood and neurocognitive function

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Beneficial effects of positive airway pressure
therapy in OSA

• Hypertension Improvement in blood pressure and
  heart rate profiles in patients with hypertension
• Congestive heart failure Improvement in cardiac
  function in patients with OSA
• Health care utilization Reduction in physician
  claims and hospital stay
• Mortality Reversal of the increase in mortality
  associated with sleep apnea

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Adverse consequences of positive airway pressure
therapy

• Aerophagia and gastric distention
• Arousals , Sleep disruption due to noise from the
  device
• Barotrauma (eg, pneumothorax, pneumomediastinum,
  pneumocephalus)
• Chest discomfort and tightness
• Claustrophobia, sensation of suffocation or
  difficulty with exhalation
• Eye irritation (conjunctivitis)
• Facial skin irritation, rash or abrasion
• Mask and mouth leaks
• Nasal congestion, dryness, epistaxis or
  rhinorrhea
• Sinus discomfort or pain

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Adherence to Positive Airway Pressure Therapy

• Therapeutic adherence in the different studies
  has varied from 46 to 80 of patients who use
  CPAP for 4 or more hours nightly on at least 70
  of monitored nights.
• Self-reports often over estimate actual CPAP use.
  
• Approximately 50 of patients are consistent CPAP
  users, and the rest are intermittent users with a
  wide range of nightly use.
• Average nightly use is between 4 to 5 hours each
  night among CPAP users. The percent of days in
  which CPAP was not used correlated with decreased
  duration of nightly use.

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Factors influencing long-term use

• Factors influencing long-term use include snoring
  history, severity of illness (AHI), perceived
  benefit from therapy, and self-reported
  sleepiness (Epworth Sleepiness Scale ESS.
• Patients with mild OSA have a particularly high
  rate of CPAP discontinuation.
• Long-term use of CPAP does not appear to be
  related to the prescribed pressure. Finally, CPAP
  usage tends to be greater among patients who
  underwent full-night CPAP titration studies
  compared to those who had split-night CPAP
  titration.

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Factors influencing long-term use

• Patterns of nightly use are often discernible by
  the first few days or weeks of initiating
  treatment.
• Adherence to CPAP therapy may be improved with
  education (eg, additional home visits ,
  participation in group clinics, periodic phone
  calls to uncover any problems and to encourage
  use, and even simple written information on the
  importance of regular CPAP use), airway
  humidification, proper selection of the CPAP
  interface, desensitization procedures for CPAP,
  early follow-up , prompt and aggressive
  management of adverse effects related to CPAP
  use, and regular assessment of CPAP adherence.
•  

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Reasons for non-adherence to positive airway
pressure therapy

• 1-Perception of lack of benefit Patient
  education
• 2-Discomfort with its use (including mask) Mask
  refitting (nasal masks, nasal pillows, full-face
  masks, ororal masks)
• 3-Noise from the device Placing device in another
  room adjacent to bedroom ,Use of ear plugs or
  noise-attenuating devices
• 4-Air leaks from the mask or mouth Mask
  refitting for mask leaks , Use of chin strap or
  full face mask for mouth leaks
• 5-Airway humidification , Treatment of nasal
  congestion
• 6-Difficulty with exhaling against high
  expiratory pressures Trial of CPAP with C-flex
  technology or bilevel positive airway pressure
  (BPAP)
• 7-Excessively high pressures Trial of automated
  positive airway pressure or Adjunctive therapy
  with sleep position treatment or oral devices

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Reasons for non-adherence to positive airway
pressure therapy

• 8-Frequent nocturnal awakenings Brief trial of
  hypnotic agents during the acclimatization phase
  of initial CPAP use (eszopiclone)
• 9-ClaustrophobiaMask refitting (eg, nasal
  pillows or oral masks),Formal program of CPAP
  desensitization
• 10-Nasal problems
• Dryness-Airway humidification (preferably
  heated) Use of nasal lubricants
• Sneezing ,Congestion , Rhinorrhea -,
  decongestants, anticholinergic agents, or
  corticosteroids , oral decongestants,
  Immunotherapy, or antihistamine agents
• Epistaxis- Nasal surgery (in patients with nasal
  anatomic abnormalities)
• 11-Gastric distention due to aerophagia BPAP
  therapy

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Automatic CPAP For OSAS
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• Auto-positive airway pressure
• Auto-positive airway pressure (APAP) devices
  provide a useful alternative for providing
  positive airway pressure (PAP) treatment for
  patients with obstructive sleep apnea (OSA) .
• One can separate the uses of these devices into
  two large categories These include
• Auto-titration PAP to determine an effective
  fixed level of continuous positive airway
  pressure (CPAP)
• Auto-adjusting PAP for chronic treatment.

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Auto-positive airway pressure devices

• When used in the auto-titration mode, the devices
  are used by the patient for a period of time (one
  night to several weeks). Information stored in
  the device is transferred to a computer and can
  be used to select an optimal fixed level of CPAP
  for chronic treatment.
• When APAP devices are used for chronic treatment
  they have the potential advantage of delivering
  the lowest effective pressure in any circumstance
  (body position, sleep stage). The mean pressure
  for the night may be lower than a single pressure
  that would be effective in all circumstances (the
  prescription pressure). For example, higher CPAP
  is usually needed in the supine posture and
  during rapid eye movement (REM) sleep.

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Auto-titrating mode

• Attended auto-titration in CPAP naïve patient
  (technologist extender)
• Unattended auto-titration in CPAP naïve patient
• Check prescription pressure after weight
  gain/loss
• Salvage a failed manual CPAP titration
• Auto-adjusting mode
• Initial chronic treatment of OSA (no titration
  needed)
• Chronic treatment in patients not tolerating CPAP
• Chronic treatment in patients with difficult
  mask/mouth leak

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DEVICE CHARACTERISTICS

• The devices differ in the respiratory variables
  that are monitored and in the algorithms used to
  adjust the delivered pressure.
• The devices typically monitor one or more of the
  following airflow (or motor speed), airflow
  profile (flattening), snoring (airway vibration),
  or airway impedance (forced oscillation
  technique).
• The algorithms used to adjust pressure are
  proprietary but determine if the delivered
  pressure should be increased or decreased.
• Depending on the type of respiratory event that
  is detected the delivered pressure is increased
  by a certain amount.

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Open unrestricted airway
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Silent partial airway obstruction
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Noisy partial airway obstruction
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Complete airway obstruction
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Open unrestricted airway
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DEVICE CHARACTERISTICS

• The S9 Series detects both obstructive and
  central sleep apneas (CSA). CSA detection uses
  the Forced Oscillation Technique (FOT) to
  determine the state of the patients airway
  during an apnea.
• When an apnea has been detected, small
  oscillations in pressure (1 cm H2O peak-to-peak
  at 4 Hz) are added to the current device
  pressure. The CSA algorithm uses the resulting
  flow and pressure (determined at the mask) to
  measure the airway patency.

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An APAP device using this technology does not
increase pressure for clear airway apneas.
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DEVICE CHARACTERISTICS

• Typically, pressure changes occur slowly over
  several minutes to prevent pressure-induced
  arousals.
• If no respiratory events are detected within a
  certain time window the delivered pressure is
  slowly decreased. Thus, the lowest effective
  pressure is delivered.
• In some of the devices machine adjustment is
  available for various mask types and for the type
  of humidifier that is being used.
• Studies comparing different APAP devices provide
  evidence that devices from different
  manufacturers will not deliver the same pressure
  for a given clinical circumstance .

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DEVICE CHARACTERISTICS

• The responses of several devices differs markedly
  in response to apnea. Some of the devices
  increased the delivered pressure in response to
  apnea while others did not .
• Comparing the 95th percentile pressure of one
  APAP device based on airflow to another based on
  the forced oscillation technique found poor
  agreement between the optimal pressure identified
  by the two devices.
• The adherence and clinical outcomes were similar
  although the median applied pressure was slightly
  higher with the device that responded to airflow
  limitation .Thus, differences in the devices do
  not always translate into differences in outcomes.

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Problems of APAP algorithms

• The problems of mask/mouth leak and central apnea
  have provided a challenge for the designers of
  APAP algorithms.
• Mask/mouth leaks tend to raise the baseline flow
  delivered by blower units and diminish the
  variations in flow during inspiration and
  expiration. The resulting airflow signal may be
  interpreted as an apnea or hypopnea and prompt an
  increase in pressure that may further increase
  leak.
• To handle the leak problem many APAP units have
  algorithms that limit pressure increases when
  leak exceeds certain values or when increases in
  blower speed no longer result in increases in
  mask pressure. Other units have leak alarms that
  can prompt the patient to adjust the mask.

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Problems of APAP algorithms

• Mouth leaks can be approached by using a chin
  strap or full-face mask.
• Algorithms often include limits on upward
  titration of pressure for apnea to avoid the
  delivery of high pressure for central apneas. For
  example, pressure is not increased above 10 cm
  H2O unless apnea is associated with snoring or
  airflow profile flattening.

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Expiratory pressure relief

• Expiratory pressure relief (C-Flex, Respironics)
  is now available for one brand of APAP devices.
• This mode allows a reduction in pressure during
  early expiration with a return to the current set
  pressure at end expiration.
• This feature could improve patient tolerance to
  pressure.

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Automatic adjustment of bi-level PAP

• APAP machines providing automatic adjustment of
  bilevel PAP (BPAP) are available. These devices
  vary inspiratory positive airway pressure (IPAP)
  and expiratory positive airway pressure (EPAP)
  according to a proprietary algorithm.
• The physician sets the minimum EPAP, maximum
  IPAP, and maximum IPAPEPAP difference.
• The option of using inspiratory and expiratory
  pressure relief (Bi-Flex R, Respironics) is
  currently available for one device brand.
• Inspiratory pressure relief allows a drop in
  pressure at end inhalation (IPAP) while
  expiratory pressure relief allows a pressure drop
  at the start of exhalation (EPAP).

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A single night profile showing changes in IPAP
and EPAP over the night with auto-bilevel
positive airway pressure.
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• Manual PAP titration is labor intensive and
  usually a single technologist can titrate only
  two patients at a time.
• Patients in some geographical areas may have
  limited or delayed access to a sleep laboratory
  offering polysomnography.
• In addition, the gold standard PAP titration
  method may result in suboptimal titrations due to
  a number of problems including poor sleep, lack
  of supine REM sleep, high mask leak, or
  uncorrected mouth leak. Patient characteristics
  such as weight gain may also render previously
  selected pressures inadequate.
• Auto-titrating PAP devices can be used to
  address some of these problems.

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AUTO-TITRATION

• One important use of APAP devices is selection of
  a fixed CPAP pressure as an alternative to
  traditional manual (attended) PAP titration .
• Information stored in the device memory can be
  analyzed and a pressure can be chosen for fixed
  CPAP treatment.
• A common method is to choose the 90th or 95th
  percentile pressure (pressure exceeded only 10
  or 5 of the time, respectively) as the
  prescription pressure. This assumes periods of
  high leak have been eliminated from the analysis.

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Efficacy of Auto-Titration

• Unattended APAP was successful at identifying an
  effective CPAP level.
• Treatment with fixed CPAP using a pressure
  identified by unattended APAP titration reduced
  the AHI to lt 10/hour in 38/40 subjects.
• In 15 of 20 patients the difference between the
  APAP pressure (taken as P95) and the CPAP chosen
  by manual titration was equal to or less than 1
  cm H2O.

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Technique of Auto-Titration

• As with manual attended PAP titrations with
  polysomnography, patient education, and mask
  fitting are essential for successful
  auto-titration. Patients must feel comfortable
  applying the mask interface and operating the
  APAP device if an unattended titration is
  planned.
• A short 20-minute trial of APAP can be very
  useful in identifying patient problems including
  claustrophobia, mask leak or an inability to
  operate the device
• The physician ordering the APAP titration
  designates the lower and upper pressure limits
  (for example, 4 and 20 cm H2O). The APAP device
  then titrates between these limits.

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Technique of Auto-Titration

• Depending on the type of APAP device utilized,
  information on applied pressure, leak, snoring,
  flattening, and a moving time average of the AHI
  is stored in the device memory. After transfer to
  a computer ,the information is available for
  review.
• It is possible to determine statistics for all or
  a portion of the data.
• Most devices allow the ability to look at one or
  more single nights of data in detail (pressure,
  leak, residual events vs. time) .

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The leak and residual AHI are low. The 95th
percentile pressure was 9.4 cm H2O. The patient
was treated with a prescription pressure of 10 cm
H2O
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Technique of Auto-Titration

• High leak can result in many devices promptly
  increasing pressure until the upper pressure
  limit is reached.
• summary statistics can be displayed for a single
  night or multiple nights. Typically available
  information includes 90th or 95th percentile
  pressure, median pressure, maximum pressure,
  maximum leak, median leak, and residual AHI.

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Technique of Auto-Titration

• Usually either the 90th or 95th percentile
  pressure is chosen for the prescription pressure.
  However, simply noting one number can be very
  misleading.
• The clinician must first determine if the
  titration duration (amount of sleep on the device
  ) was adequate and if the residual AHI is
  reasonably low (AHI lt 510/hour).
• Patients with suboptimal or inconclusive APAP
  titrations should have a repeat APAP titration or
  be referred for an attended lab PAP titration.

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Technique of Auto-Titration

• High-residual AHI could be secondary to frequent
  central apneas, high leak, or too low maximum
  pressure limit.
• High leak could be secondary to inadequate mask
  seal or mouth leak if a nasal mask is being
  utilized.
• Patients with a high AHI and leak may undergo a
  repeat APAP titration after mask adjustment or
  change to a full-face mask (or addition of a chin
  strap) as indicated.
• A persistently high-residual AHI despite repeated
  attempts at APAP titration would be an indication
  of the need for a traditional manual PAP
  titration.

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The leak is higher than ideal (gt 0.4 L/s) at
times. However, the residual AHI remained low.
The 95th percentile pressure was 7.8 cm H2O. The
prescription pressure was chosen to be 8 cm H2O.
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The leak is very high. The pressure increased to
the upper limit (16 cm H2O) and remained there
for most of the night. The AHI was also elevated.
This titration would need to be repeated with a
better mask seal.
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Technique of Auto-Titration

• A number of portable monitoring units can
  interface with selected APAP devices. For
  example, airflow, respiratory effort, oxygen
  saturation, body position, and delivered pressure
  can be recorded for clinician analysis .
• This is especially helpful if one night of APAP
  titration is utilized. For example, absence of
  supine sleep could result in a lower than
  typically needed prescription pressure. This is
  also a reason that it is often helpful to have
  the patient use the APAP device for several
  nights.
• Average statistics over a week may more
  accurately represent a typical nights pressure
  requirements. Information from pulse oximetry
  during the APAP titration can identify the need
  for the addition of supplemental oxygen.

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In summary

• Auto-titrating PAP devices can be useful for
  identifying an appropriate fixed CPAP level in
  appropriate patients.
• Unattended as well as attended titration can be
  effective. However, it is likely that unattended
  APAP titration will not be effective in a
  significant proportion of OSA patients.
• Patients with a significant proportion of central
  apneas, those with low baseline SaO2 values or
  who have difficulty applying the mask and/or
  operating an APAP device are best studied using
  attended manual titration with polysomnography.

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In summary

• A brief practice trial with APAP may be useful to
  identify mask leak or nasal congestion problems
  requiring intervention before the patient takes
  the APAP device home.
• If APAP titration is performed, close review of
  the data is needed to ensure that the titration
  was adequate.
• Those patients not having an adequate APAP
  titration should be referred for a traditional
  CPAP titration.

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CHRONIC TREATMENT WITH AUTO-POSITIVE AIRWAY
PRESSURE
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AUTO-ADJUSTING POSITIVE AIRWAY PRESSURE

• When originally developed one anticipated
  advantage of APAP devices was that delivery of
  the lowest effective pressure in any circumstance
  (sleep stage, body position) would improve
  acceptance and adherence to positive pressure
  treatment.
• This was based on the premise that a lower mean
  nightly pressure would improve patient tolerance
  to PAP treatment. Alternatively, chronic
  treatment with an auto-adjusting device would
  obviate the need for an attended or unattended
  PAP titration.

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Auto-Positive Airway Pressure Vs. CPAP Treatment

• A number of studies have examined the hypothesis
  that chronic treatment with auto-adjusting PAP
  would increase the adherence.
• Some studies did find higher adherence with APAP
  compared to fixed CPAP treatment. Several other
  studies did not confirm this result.
• In evaluating studies of adherence several issues
  must be considered. First, pressure intolerance
  is not the major issue for many patients .
  Second, the difference in the mean pressure on
  APAP and an adequate fixed pressure is often only
  1 to 2 cm H2O . One would not expect such a small
  pressure difference to change adherence

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Auto-Positive Airway Pressure Vs. CPAP Treatment

• One might expect a potential advantage for APAP
  devices in patients with pressure intolerance,
  high prescription pressures, or a large variation
  in the required pressure during the night
  (postural or REM-related OSA) . Thus, if a
  patient is having difficulty with CPAP, a trial
  of APAP is a reasonable intervention.
• If APAP is preferred, improved adherence is
  likely with this mode of treatment compared to
  fixed CPAP. Furthermore, information stored in
  the machine such as leak or residual events may
  help diagnose problems with treatment .

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Auto-Positive Airway Pressure Vs. CPAP Treatment

• Patients with difficulty tolerating CPAP due to
  pressure intolerance (cannot breathe out) are
  often switched to BPAP.
• APAP treatment does not improve adherence over
  fixed CPAP selected by manual titration
• Patients diagnosed with OSA could be treated with
  chronic APAP without the need for either
  traditional laboratory titration or
  auto-titration. Any additional cost of APAP
  devices over CPAP would usually be lt the cost of
  an in-laboratory CPAP titration. Both a cost
  saving and a reduction in the time needed to
  adjust the PAP treatment occur to a satisfactory
  level.
• The optimal level of CPAP determined by an
  attended in-laboratory titration often requires
  alteration for patient tolerance, side effects,
  or control of daytime sleepiness.

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Technique of Chronic Auto-Positive Airway
Pressure Treatment

• The physician usually orders the lower and upper
  limits of positive pressure. The APAP device then
  delivers the lowest effective pressure between
  these limits.
• The upper and lower pressure limits could be
  placed as wide as possible (418 cm H2O) or
  narrowed based on information from a previous
  CPAP titration or previous nights of APAP use.
• Some patients find starting at 4 cm H2O
  uncomfortable and it may take some APAP machines
  several minutes to reach a pressure level that
  they find comfortable. In this case the lower
  pressure could be increased to 610 cm H2O.
• Awakening with the feeling of insufficient
  pressure could be another situation in which the
  lower pressure limit should be increased.

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Technique of Chronic Auto-Positive Airway
Pressure Treatment

• Bloating or evidence of excessive mouth leak
  might be an indication to lower the upper
  pressure limit .Alternatively, if the 90th
  percentile pressure essentially equals the upper
  pressure limit, then a higher upper pressure
  limit is likely needed (especially if the
  residual AHI is high).
• Information on delivered pressure is not the only
  data stored in the APAP device that is
  potentially useful for tailoring treatment.
• High leak may indicate the need for another mask
  or a full-face mask (mouth leak).

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Technique of Chronic Auto-Positive Airway
Pressure Treatment

• A high-residual AHI might indicate a need for an
  increase in either the lower or upper pressure.
• A high number of residual apneas might suggest
  that central apneas could be present.
• Financial constraints may limit the use of APAP
  devices for chronic treatment of OSA at least in
  some circumstances.

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Recommendations

• APAP is not recommended to diagnose OSA.
  (Standard)
• Patients with congestive heart failure,
  significant lung disease such as chronic
  obstructive pulmonary disease, patients expected
  to have nocturnal arterial oxyhemoglobin
  desaturation due to conditions other than OSA
  (e.g., obesity hypoventilation syndrome),
  patients who do not snore (either naturally or as
  a result of palate surgery), and patients who
  have central sleep apnea syndromes are not
  currently candidates for APAP titration or
  treatment. (Standard)

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Recommendations

• APAP devices are not currently recommended for
  split-night titration. (Standard)
• Certain APAP devices may be used during attended
  titration with polysomnography to identify a
  single pressure for use with standard CPAP for
  treatment of moderate to severe OSA. (Guideline)
• Certain APAP devices may be initiated and used in
  the self-adjusting mode for unattended treatment
  of patients with moderate to severe OSA without
  significant comorbidities (CHF, COPD, central
  sleep apnea syndromes, or hypoventilation
  syndromes). (Option)

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Recommendations

• Certain APAP devices may be used in an unattended
  way to determine a fixed CPAP treatment pressure
  for patients with moderate to severe OSA without
  significant comorbidities (CHF, COPD, central
  sleep apnea syndromes, or hypoventilation
  syndromes). (Option)
• Patients being treated with fixed CPAP on the
  basis of APAP titration or being treated with
  APAP must have close clinical follow up to
  determine treatment effectiveness and safety.
  This is especially important during the first few
  weeks of PAP use. (Standard)
• A re-evaluation and, if necessary, a standard
  attended CPAP titration should be performed if
  symptoms do not resolve or if the APAP treatment
  otherwise appears to lack efficacy .(Standard)

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CONCLUSIONS

• APAP devices can be effective in the
  auto-titrating and auto-adjusting modes. They
  provide a useful titration or chronic treatment
  alternative for patients with sleep apnea.
• Success depends on proper patient selection,
  education, and detailed physician review of the
  stored information.
• Treatment or titration results could vary between
  brands of APAP devices.
• The devices may not work well in patients with
  central apneas or those with large mouth or mask
  leak.

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CONCLUSIONS

• Careful physician evaluation of treatment
  efficacy is essential. For example, it is
  possible that a given patient may have better
  alertness or sleep with a slightly higher or
  lower pressure than the 90th or 95th percentile
  pressure identified by APAP titration.
• Familiarity with type of information provided by
  a given brand of device is essential to benefit
  from the stored information.
• As with any type of PAP treatment, close
  follow-up of objective adherence and outcome
  measures such as subjective sleepiness is
  essential.

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