Download Advanced PAP Modalities: Understanding the Tools

Advanced Positive Airway
Pressure (PAP) Treatment
Modalities
Nic Butkov, RPSGT
Asante Sleep Center
Medford, Oregon
Currently-Available PAP Modalities
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CPAP
Bi-level PAP spontaneous (S) mode
Bi-level PAP spontaneous/timed (S/T) mode
Bi-level PAP timed (T) mode
Bi-level PAP with pressure control (PC or PAC) mode
Average Volume-Assured Pressure Support (AVAPS™)
or Intelligent Volume-Assured Pressure Support
(iVAPS™)
Adaptive servo-ventilation (ASV) mode
Treatment Applications
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CPAP for upper airway obstruction
Bi-level S for basic ventilatory support
Bi-level S/T for ventilatory support with back-up
respiratory rate
Bi-level PC or PAC for ventilatory support with
fixed inspiratory time
AVAPS or iVAPS for ventilatory support with
regulation of tidal volumes and back-up rate
ASV for central sleep apnea
Basic Concepts of
Bi-Level PAP Therapy
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Expiratory positive airway pressure (EPAP)
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Provides the baseline PAP level
Maintains upper airway patency during expiration
Prevents alveolar collapse and improves functional
residual capacity (FRC)
Reduces work of breathing and improves oxygenation
Inspiratory positive airway pressure (IPAP)
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Maintains upper airway patency during inspiration
Provides pressure support to augment ventilation
Decreases work of inspiratory muscles
Setting the EPAP
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The baseline EPAP level is usually kept low (4 –
5 cwp) unless closed airway apneas are present
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EPAP can also be increased in select cases to
help recruit the alveoli and improve oxygenation
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High EPAP levels may be contraindicated in
some patients
Setting the IPAP for Pressure
Support
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EPAP-IPAP span = pressure support (PS)
A low EPAP-IPAP span (PS of 4 cwp or less)
offers expiratory relief, but is generally
insufficient for added ventilatory support
For patients needing added ventilatory support,
a span of 6 cwp or higher is usually required
(higher PS = higher breath volumes)
However, excessive PS may lead to upper
airway instability and may be contraindicated for
some patients
Timed Inspiration and I:E Ratio
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Timed inspiration (Ti) is used with some PAP
modalities
When using Ti, it is essential to calculate the
resulting inspiratory to expiratory (I:E) ratio
based on the respiratory rate
For example, at a rate of 12 bpm, each breath
cycle is 5 seconds in duration. An inspiratory
time of 1.66 sec. with an expiratory time of 3.34
sec. delivers a 1:2 ratio
Timed Inspiration (cont.)
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Shorter inspiratory times are generally used for
patients with obstructive lung conditions, to allow
longer time for expiration
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Longer inspiratory times are generally used for
patients with restrictive lung conditions;
however, inspiratory time should never exceed
the length of expiratory time
Timed Inspiration (cont.)
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Respironics applies Ti only to machinedelivered breaths in their ST mode
ResMed applies minimum and maximum
inspiratory times limits to all breaths in their S,
ST, and iVAPS modes
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The Min Ti sets the obligatory Ti baseline
The Max Ti allows for longer inspiratory times based
on the patient’s own breath cycle
In PC or PAC mode, fixed Ti is applied to all
breaths
Setting the Ti
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Ti settings are based on clinical indicators,
making certain that appropriate I:E ratios are
maintained
When applied only to machine-delivered
breaths, Ti is set relative to the back-up rate
When Ti is applied to all breaths, the patient’s
spontaneous rate must be taken into account
during all stages of sleep under all
circumstances
PAP Trigger and Cycle
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PAP Trigger = transition from EPAP to IPAP
PAP Cycle = transition from IPAP to EPAP
Medium trigger and cycle sensitivities work well
in most cases
Higher trigger sensitivity and lower cycle
sensitivity may be useful in restrictive or
neuromuscular disease
Higher cycle sensitivity may be useful in
obstructive lung disease
Rise Time
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Rise time = the amount of time (measured in
milliseconds) set for the PAP device to reach
IPAP when a breath is triggered
Generally, shorter rise times are used for
obstructive lung conditions; longer rise times are
used for restrictive lung conditions
Rise time should be set according to efficacy of
treatment and patient comfort
Mask Selection
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Mask Type
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Nasal mask
Nasal pillows
Oronasal (full-face) mask
Mask type makes a difference!
Changing between nasal and full-face
mask may require additional PAP
adjustments
Mask and Tubing Settings
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All PAP machines need to be set correctly
for the type of mask and tubing used
Bi-Level PAP S Mode
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Sometimes used as a substitute for CPAP
Can be used for ventilatory support in
patients with COPD, neuromuscular
disease and obesity hypoventilation
Not appropriate for patients with CheyneStokes respiration or other forms of central
apnea
Basic Bi-Level S Settings
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EPAP
IPAP
Rise time
Timed inspiration (minimum-maximum
limits) are used on some equipment
(ResMed)
Bi-Level S Mode Titration
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Starting pressures are typically 8/4 cwp
Rationale for adjusting EPAP and IPAP
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EPAP is increased for closed-airway apneas
(keeping the same EPAP-IPAP span)
IPAP is increased for residual hypopneas,
RERAs and/or snoring
IPAP is further increased for added ventilatory
support (if indicated)
Diagnosic study: severe hypoxemia during REM sleep
Improved O2 saturation levels and sleep architecture with bi-level PAP
Settings: EPAP = 4 cwp, IPAP = 11 cwp (S mode)
Bi-Level S/T Mode
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S/T mode is used when a back-up rate is
required
Sometimes used to treat select patients
with opioid induced central apnea
S/T mode is generally not recommended
for central apneas with Cheyne-Stokes
respiration
Basic Bi-Level S/T Settings
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EPAP
IPAP
Back-up rate
Timed inspiration (Ti)
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Fixed Ti is applied only to machine-delivered breaths
(Respironics)
Minimum-maximum Ti limits are applied to all breaths
(ResMed)
Rise time
a
Fragmented sleep
Opioid-induced Biot’s respiration
Sleep is partially improved
Bi-Level S/T 12/4 cwp with back-up rate of 8 bpm
Bi-Level PC or PAC mode
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Fixed timed inspiration is applied to all breaths
Ventilatory support is achieved by balancing the
EPAP-IPAP span with timed inspiration
Inspiratory time must be set to maintain
appropriate I:E ratio relative to the patient’s
respiratory rate during all stages of sleep under
all circumstances
PC or PAC mode is sometimes prescribed for
select patients with neuromuscular disease
Basic Bi-Level PC/PAC
Settings:
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EPAP
IPAP
Back-up rate
Timed inspiration (applied to all breaths)
Rise time
Combined effect: NMD, opioid use and upper airway obstructive component
Bi-level S/T: 15/6 cwp with back-up rate 10 bpm
PC mode: 12/6 cwp; Ti 2 sec., back-up rate 10 bpm (IE ratio = 1:2)
Adaptive Servo-Ventilation
(ASV)
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Intended for treating central sleep apnea
Not appropriate for hypoventilation syndromes
Variable EPAP maintains upper airway patency
Variable IPAP with back-up rate delivers
pressure support
Based on a recent study, ASV is contraindicated
for heart failure patients with moderate-severe
CSA and left ventricular ejection fraction <45%*
* Serve-HF Clinical Trial
Considerations Regarding Central Apneas
that are Unresponsive to CPAP
(Possible Causes)
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Uncorrected obstructive apneas that appear
ostensibly central
Central apneas caused by excessive PAP levels
Central apneas temporarily appearing during
adjustment to PAP therapy
Repetitive sleep-onset central apneas
Cheyne-Stokes respiration
Opioid-induced Biot’s respiration
Cheyne-Stokes Respiration vs.
Biot’s Respiration
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Cheyne-Stokes respiration is characterized by
crescendo-decrescendo breathing with central
apnea or hypopnea, as often seen in patients
with congestive heart failure
Biot’s respiration is characterized by brief
clusters of shallow breaths with central apnea or
hypopnea, as typically seen in patients using
opioid medications
Cheyne-Stokes respiration
Biot’s respiration
Biot’s / ataxic respiration
Basic ASV Settings:
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EPAP min
EPAP max
PS min
PS max
Respironics also provides selection of auto
vs. manual back-up rate, rise time and
maximum pressure limit
NREM sleep with arousals
Diagnostic study – central sleep apnea with obstructive component
Transitional sleep
ASV titration (EPAP - 5; min PS - 0; max PS - 10; back-up rate - auto)
Sleep is becoming more consolidated
ASV titration continued (same settings)
Quiet NREM sleep
ASV titration is complete (same settings)
Volume-Assured Pressure Support
(AVAPS or iVAPS)
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Can be used for neuromuscular disease,
obesity hypoventilation, restrictive or
obstructive lung disease, or for select
patients with opioid-induced central apnea
Uses a variable range of pressure support
to maintain pre-set target tidal volumes
Tidal Volumes
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Tidal volume = volume of air moved in and out of
the lungs with each breath
In healthy adults, normal tidal volumes are in the
range of approximately 500 milliliters per breath,
or 7 milliliters per kilogram of body weight
When using AVAPS or IVAPS, target tidal
volumes are generally calculated based on ideal
body weight relative to the patient’s height
(starting values of 6 - 8 ml/kg are usually
applied, or as directed by the physician)
AVAPS Settings:
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S, ST or PC mode
Target tidal volume
Back-up rate (ST and PC modes)
EPAP
Minimum IPAP
Maximum IPAP
Timed inspiration
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Applied only to delivered breaths in ST mode
Applied to all breaths in PC mode
Rise time
iVAPS Settings
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Patient height
Target respiratory rate
Target alveolar ventilation
EPAP
Minimum pressure support
Maximum pressure support
Minimum Ti
Maximum Ti
Trigger Sensitivity
Cycle Sensitivity
Rise time
Evaluating the Respiratory Data
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The PAP flow and pressure channels should be
checked for synchrony with the respiratory effort
channels
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Asynchronous waveforms may be caused by
excessive mask leaks, mouth breathing,
incorrect inspiratory time settings, or inadequate
trigger and/or cycle sensitivity settings
PAP flow waveforms are synchronous with the chest and abdomen waveforms
PAP flow waveforms are asynchronous with the chest and abdomen waveforms
CPAP of 11 cwp with EPR of 3 – synchronous pressure and flow signals
Asynchronous pressure and flow signals – sporadic pressure support
Asynchronous pressure and flow signals with excessive PAP levels
Fine-Tuning the Settings
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Strategies for improving PAP flow synchrony:
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Check and correct mask leaks
Consider the possibility that the PAP levels might be
too high
Check for appropriate inspiratory time values (if
applicable)
Check for appropriate trigger and/or cycle sensitivity
settings (if applicable)
Try manipulating the rise time setting (extending the
rise time can sometimes help prevent mask leaks
during inspiration)
Evaluating the Titration
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Was the appropriate PAP modality selected?
What type of mask was used and why?
Was the machine set correctly for type of mask
and tubing used?
Was baseline EPAP increased and if so, why?
If variable EPAP was used, were the settings
appropriate?
How much pressure support was applied and
was it appropriate?
If variable pressure support was used, was the
range sufficient?
Evaluating the Titration (cont.)
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What was the patient’s respiratory rate during
wakefulness, during NREM sleep and during
REM sleep?
Was timed inspiration applied and was it
appropriate relative to the patient’s respiratory
rate?
Was timed inspiration applied only to delivered
breaths or to all breaths?
If minimum-maximum inspiratory time limits were
applied, were the settings appropriate?
Evaluating the Titration (cont.)
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If trigger and cycle sensitivity settings were
adjusted, were they appropriate and effective?
How was the rise time selected and was it
appropriate and comfortable for the patient?
Did the PAP flow waveforms appear
synchronous with the respiratory effort
waveforms?
What were the tidal volumes readings during the
study (NREM and REM sleep in all body
positions)?
Evaluating the Titration (cont.)
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What were the O2 saturation readings during the
study (NREM and REM sleep in all body
positions)?
What were the recorded leak values during the
study (NREM and REM sleep in all body
positions)?
Was the head of the bed elevated during the
study and if so, did it replicate the patient’s
home environment?
Was supplemental oxygen used during the study
and was it necessary?
Evaluating the Titration (cont.)
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Was there any evidence of residual upper
airway obstruction or resistance (NREM and
REM sleep in all body positions)?
Were open-airway central apneas and
hypopneas adequately resolved with treatment?
Was the patient breathing quietly and effortlessly
(based on direct observation)?
Was the patient’s sleep quality improved?
Did the patient tolerate the treatment well?
Did the patient feel better after treatment?
Summary
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EPAP and IPAP should be sufficient, but not
excessive
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All PAP settings (such as back-up rates, Ti, etc.)
must be verified as appropriate for the patient
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Efficacy of treatment involves maintaining upper
airway patency, providing adequate ventilatory
support, and improving quality of sleep