Bronchial Asthma

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Positive Airway Pressure For Sleep Disordered
Breathing
By Ahmad Younis professor of Thoracic Medicine
Mansoura University
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PAP for SDB
Studies have shown CPAP to increase upper airway
size, especially in the lateral dimension.
Positive intraluminal pressure expands the upper
airway (pneumatic splint) and increase in lung
volume due to CPAP (due to a downward pull on
upper airway structures during lung expansion
tracheal tug), may also increase upper airway
size and/or stiffen the upper airway walls,
making them less collapsible.
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Positive airway pressure (PAP) can
1-Bring the AHI down to below 5 to 10/hr in the
majority of patients. 2-Improves arterial oxygen
saturation and decreases respiratory arousals.
3-Increase the amount of stage N3 and stage
R. NB 1-An occasional patient with very severe
apnea will have a large REM or stage N3 sleep
rebound on the first night of PAP
treatment. 2-The most difficult problem with PAP
treatment is that adherence is suboptimal in a
large percentage of patients.
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MODES OF PAP
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MODES OF PAP

• 1- CPAP Continuous pressure during inhalation
  and exhalation.
• 2- BPAP (S mode)
• IPAP.
• EPAP.
• IPAP - EPAP PS.
• Flexible PAP, expiratory pressure relief (Cflex,
  EPR)
• Pressure falls in early exhalation
• Returns to set pressure at end-exhalation.
• 3-APAP autotitrating, autoadjusting PAP
  (autoCPAP)
• Titrates between maximum and minimum pressure
  limits to prevent apnea, hypopnea, airflow
  flattening, and airway vibration (snoring).

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MODES OF PAP

• 4- Auto-BPAP Titrates IPAP and EPAP between
  EPAPmin and IPAPmax with PSmin 3 and PSmax set
  by the clinician. PSmax constrained by IPAPmax.
• 5- BPAP with backup rate (NPPV)
• BPAP modes
• ST.
• T.
• 6- ASV PS varies to stabilize breathing.
• EPAP set to eliminate airway obstruction.
• Backup rate AVAILABLE

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Autoadjusting (autotitrating) PAP, devices

• 1-Autotitrating PAP to select an effective
  level of CPAP without the need for an attended
  titration
• 2- Aautoadjusting PAP for chronic treatment with
  the advantage of delivering the lowest effective
  pressure in any circumstance.
• Chronic treatment with APAP would also eliminate
  the requirement for a CPAP titration .

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The APAP algorithms vary between different
devices, but in most instances the pressure
changes in response to variations in airflow
magnitude (apnea or hypopnea), airflow limitation
(flattening of the airflow contour), and snoring

• New technology used by Philips-Respironics
  attempts to differentiate clear airway apneas
  versus obstructive apneas by delivering a small
  pressure pulse (12 cm H2O pressure pulse) after
  approximately 6 seconds of a reduction in
  airflow. If the pressure pulse does produce an
  increase in flow, this is compatible with an open
  airway (clear airway). If the pressure pulse does
  not increase flow, the airway is closed.

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An APAP device using this technology does not
increase pressure for clear airway apneas.
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Autobilevel positive airway pressure with a
minimum (EPAP) of 6 cm H2O and a maximum (IPAP)
of 25 cm H2O.
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ASV is a variant of BPAP that was developed to
treat Cheyne-Stokes central apnea. Both ASV and
BPAP devices with a backup rate are approved for
use with patients with central apnea and complex
sleep apnea
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The ASV device responds to variation in flow by
increasing PS when flow and ventilation are low
and decreasing PS when flow is high.
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COMFORT MEASURES

• Ramp
• Most PAP devices, with the exception of certain
  APAP devices, allow the patient to trigger the
  ramp option.
• In the ramp option, the pressure starts at a
  preset levelusually a low level of CPAPand then
  slowly increases to the treatment pressure (CPAP)
  over the set ramp time
• Some APAP devices have a settling time at a low
  pressure before the device starts autoadjusting
  pressure.

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Flexible Pressure

• Two manufacturers of PAP devices have developed
  flexible PAP
• 1- Philips-Respironics provide several comfort
  options (Cflex, Cflex, and Aflex)
• 2- ResMed devices offer expiratory pressure
  relief (EPR).
• In Cflex, expiratory pressure drops at the start
  of exhalation but returns to the set CPAP at
  end-exhalation. The amount of drop (Cflex 1, 2,
  3) is determined by a proprietary algorithm.

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• Cflex adds a smoothing of the transition from
  inhalation to exhalation.
• Aflex is a form of APAP that provides a 2 cm H2O
  lower end-expiratory pressure than the
  inspiratory pressure (in addition to the features
  of Cflex
• For both BPAP and autoBPAP devices, a form of
  expiratory pressure relief is available (Biflex).
  The technology provides a smoothing of transition
  from IPAP to EPAP as well as expiratory pressure
  relief during the EPAP cycle (Biflex 1, 2, 3). .

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B-Flex found in the Bipap
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Humidification

• Today, most PAP devices come with the option of
  an integrated heated humidification system. They
  can be used in the cool humidity mode if desired.
  Heated humidity can deliver a greater level of
  moisture than cool humidification and may be
  especially useful in patients with mouth leak or
  nasal congestion. Mouth leak can cause a dramatic
  fall in relative humidity and a loss of humidity
  from the upper airway/CPAP system, thus drying
  the nasal or oral mucosa.
• Use of heated humidification is recommended to
  improve CPAP utilization. In the clinical
  guidelines for titration, having HH available for
  titration was recommended. .

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Interfaces

• Nasal pillow masks are often better tolerated
  than traditional nasal masks by patients with
  claustrophobia and are useful in patients with a
  mustache or edentulous patients who have no
  dental support for the upper lip.
• For patients who have severe nasal congestion or
  open their mouths during PAP treatment, oronasal
  (full face masks) and oral interfaces are
  available
• If the patient gets up to use the bathroom during
  the night, we encourage disconnection of the hose
  from mask rather than taking off the mask. Masks
  that are removed in the middle of the night are
  often not replaced. .

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MODES OF PAP
INFLAMMATION
Airway Hyperresponsiveness
Airflow Obstruction
Symptoms
Risk Factors (for exacerbations)
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INDICATIONS FOR PAP TREATMENT

• Patients must be diagnosed with either a PSG or a
  home sleep test .
• CPAP treatment if the AHI is 15/hr or greater
  with or without symptoms or if the AHI is 5/hr or
  greater but less than 14/hr if certain symptoms
  (excessive daytime sleepiness, impaired
  cognition, mood disorders, or insomnia) or
  certain disorders (hypertension, ischemic heart
  disease, or history of stroke) are present.

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