beyond traditional pap therapy
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Beyond Traditional PAP therapy. Brian Gaden BSRT, RRT, RPSGT Sleep Consultant Philips Home Healthcare Solutions. Objectives. Review of pathology behind the need for ventilation Central Sleep Apnea Overlap Disease Obesity Hypoventilation Neuromuscular Disorder - PowerPoint PPT PresentationTRANSCRIPT
Beyond Traditional PAP therapy
Brian Gaden BSRT, RRT, RPSGT
Sleep Consultant Philips Home Healthcare
Solutions
Objectives Review of pathology behind the need for
ventilation Central Sleep Apnea Overlap Disease Obesity Hypoventilation Neuromuscular Disorder
Describe the use of Servo ventilation for patients with Complex and Central Apnea
Describe the use of BiPAP S/T with AVAPS for patients with pulmonary disorders
Describe the titration methods for patients requiring NIV
Sleep Impact on
the Respiratory
System
Cerebrum
Brain Stem
Spinal Cord
Controller
MechanicoreceptorsChemorecptors
Sensors/Feedback
Effector
Respiratory Muscles
Airway Vessels and Function
Gas ExchangeResult
Sleep Disordered Breathing- Physiology review
Factors that may impact the function of the brain during sleep • Change in blood flow• Drug administration • Change in cortical inputs• Disease of the
Cerebrum/Brain Stem/Spinal cord
• Loss of motor neurons due to disease
• Severing of the motor neurons
CerebrumBrain StemSpinal Cord
Controller
Impact of the respiratory muscles and airway vessels during sleep
• Any change can directly impact the respiratory system – Positional changes– Damage or loss of the
respiratory muscles will – Damage to the airway
support system – Damage to the airway
vessels– Damage or loss of blood
supply
EffectorRespiratory
MusclesAirway Vessels
Function
Problems with Gas Exchange during sleep Gas ExchangeResult
• There can be several reasons for gas exchange to not occur:– Poor perfusion of the
pulmonary system– Positional changes in
perfusion– Destruction of the alveolar
sacs due to underlying disease
– Lack of ability to move gas into the alveolar sacs • Muscle loss• Conduction problem with
nervous system impulse
Systemic monitoring systems that influence ventilation and
oxygenation • Central Chemoreceptors– Found inside of the brain to
regulate and stimulate the respiratory system in the brain stem
– Feedback system is thru acid/ carbon dioxide levels in the brain and body
• Peripheral Chemorecptors– Chemical Receptors found on
the aortic arch and carotid artery
– Send impulses to the brain stem to change the respiratory rate and pattern
– Respond to both oxygen and carbon dioxide levels
MechanicoreceptorsChemorecptors
Sensors/Feedback
What happens in the lungs?
One thing to remember The primary drive to breathe is
based upon the CO2 level in the blood.
The secondary drive to breathe is based upon the O2 level in the blood.
If CO2 levels are too high, the body responds by increasing ventilation to get rid of excess CO2
If CO2 levels are too low, the body responds by decreasing ( or stopping ) ventilation to allow CO2 to build back to normal levels
Effect of Sleep on Normal Respiration
McNicholas, Chest 2000; 117:488-538
20 – 50%
ABG changes due to Decrease in Min. V
0.5 – 1.5 LPM
Normal Changes During Sleep Decrease in chemoreceptor sensitivity
Both oxygen and CO2 by 20 – 50%
Reduction in Alveolar Ventilation due to decrease in Reticular Activation Center activity Body position & increased airway resistance Decrease in tidal and minute volume
Sum total of physical change causes the following for a normal patient : Increase PaCO2 - 2 – 8 mmHg Decrease PaO2 - 3 – 10 mmHg Decrease SaO2 - by 2%McNicholas, Chest 2000; 117:488-538
The complicated world of sleep disordered breathing
Vast majority of SDB patients typical OSA profile
80 – 90% OSA AHI controlled by CPAP therapy
Central Sleep Apnea Idiopathic Central Sleep Apnea Complex Sleep Apnea
“CPAP Emergent events” Periodic Breathing (such as CSR)
CO2 and Chemoreceptor issue Usually secondary to CHF
Pulmonary Disorders: CO2 retention
Overlap Syndrome (OSA and COPD) Restrictive Disorders Neuromuscular Disorders Obesity Hypoventilation Syndrome
OSAIdiopathic/PBComplex
Idiopathic Central Sleep Apnea
Problem is with the controller mechanism (the brain)
Can be secondary to stroke, brain injury
Cause not always known
Treatment is the same
Idiopathic central sleep apnea – PSG view
• No output from respiratory center of the brain causing lack of movement of the thorax.
• No movement of thorax & abdomen causes apnea
Idiopathic central sleep apnea Cause of Idiopathic Central Apnea:
The respiratory center of the brain does not fire during sleep causing periodic apnea (see below)
Seen during the diagnostic night and titration night Generally seen in non REM sleep clears during REM sleep Generally seen in younger populations
May appear as part of a neurological disease process or injury Relationship between chronic opioid therapy and central sleep
apnea1
Impacts very small population of people
Apnea Apnea 1 Webster,et al. American Academy of Pain Medicine 2007
Treatment recommendations for
idiopathic central sleep apnea Oxygen therapy
Respiratory Stimulant medications
NIV BiPAP S/T Must be able to differentiate
between Idiopathic CSA and Complex Apnea
Remember:<2% of SDB
What is complex apnea?Complex apnea occurs with
the application of PAP therapy
Central apneas occurRelative CO2 drop from
application of PAP therapyREMEMBER: PAP does NOT
fix central events!
• Complex Apneas on CPAP 7 cm H2O
• Cycle time for events is ~30 seconds Pittman Slides
Complex Sleep Apnea - Characteristics
Characteristics of Complex Sleep Apnea Typically emerges during titration not
during diagnostic PSG Emerges with the implementation of CPAP to
alleviate OSA events1
Occur at ~ 30 second intervals vs. 60-90 second interval with CSR
Complex Sleep Apnea is a mixture of OSA which converts over to central apnea upon CPAP application and opening of the airway 1
Minimal data available Estimated prevalence 1/7 or ~15% of the SDB
population
1 Morganthaler, et. al. Sleep 2006; 29 (9):1203-1209
Possible Cause of Complex Sleep Apnea?
Theory of Complex Apnea is due to a combination of airway resistance and respiratory drive 12
Theory: once airway open with low levels of CPAP, OSA is eliminated with CPAP. The airway now allows for normal RR causing instability of CO2 receptors.
With a “normal” breathing pattern, the patients brain function reads the change in CO2 and causes hypoventilation to occur. (slight change of 2 can cause instability)
Hyperventilation then leads to development of central apneas causing complex breathing events
Chemoreceptor issues unmasked when OSA is eliminated
1 Interview with Dr. Younes & Dr. Sanders2 Moganthaler, et.al. Sleep 2006
Complex
~35 sec
Treatment Strategies for Complex Sleep Apnea
CPAP + Time on Therapy to reset chemoreceptors for patient Must qualify with AHI > 5 with EDS OR
AHI >15 To move to AutoServo Ventilation must
meet RAD criteria
No improvement, try alternatives below
Medications + CPAP Auto Servo Ventilation
RAD policy for Complex Sleep Apnea
Key Strategy When performing a titration where
complex apnea presents, patience is the key
Usually a difficult and tedious titration
In most cases, the CPAP emergent apnea will resolve with time to adjust to PAP pressure.
Servo may be required if CSA persists
Periodic Breathing (such as CSR)
What is the population mix?What do they look like on PSG?
What is the treatment strategy for PB?
Periodic Breathing (such as Cheyne Stokes)
Prevalence normally about 5% of patients Increase in prevalence with special
populations Heart Failure (~40%-50%) Neurologic disorders (stroke) Altitude Renal Failure, Dialysis patients
Characteristics Emerges in non REM sleep May resolve in REM sleep May be seen prior to study and during
diagnostic study
Periodic Breathing Characteristics: waxing and waning breathing
pattern Length is based on disease process causing the
breathing pattern Longer events for patients in heart failure 1 (picture A)
50-70 second events of CSR then followed by normal respiration (waxing and waning of Respiration) in patients with Heart failure 1
Shorter events in those with preserved heart function 1 (picture B)
20 – 40 seconds on length with those with preserved heart function 1
~60 sec1 Thomas, et. al. Curr. Opin Pulm Med. 2005
A B
Treatment Recommendations for PB
If patient has PB due to disease process, medical management of disease will help with management of PB Medical Management of Heart Failure is KEY
in treatment of CSR 1
If the patient has predominately CSR, (CSR >50%), CSA > 5, AHI
CPAP Therapy1
Auto Servo Ventilation3
Bi-Level Therapy with back up rate 2
If the patient has predominately OSA (<50% CSR), CPAP should be prescribed
1 Javaheri, et. al. Curr Treatment Option in CV Med: 2005:7:295-3062 Kasi, et. al. Circ. J.; 200569:913-9213 Teschler et al, AJRCCM, 164:614-419, 2001
Complicated Patients Patients have
complicated and variable breathing
Auto PAP treats OSA
Auto Backup rate treats CSA
Variable IPAP (PS) treats periodic breathing
ASV Initial Settings EPAP min - ?? EPAP max -
20cwp PS min – 0 PS max- 10 Backup rate-
Auto Max pressure -
25
Be patient Document Must control
leak How much leak
is too much?
Central Sleep Apnea Summary
Idiopathic CSA: BiLevel PAP with Backup rate
Complex Apnea: PAP with patience. Servo if needed
Periodic Breathing: Servo Ventilation. BiPAP Auto SV Advanced
Absolute Hypoventilation Overlap disease Obesity
Hypoventilation Syndrome
Neuromuscular Disease
CO2 retention
Strategy: Improve ventilation
Provide consistent Tidal Volume (Vt)
Volume targeted pressure ventilation (AVAPS)
Consistent CO2 elimination
Improving Quality of Life
COPD Overlap Syndrome A combination of OSAHS and COPD Patients with overlap disease usually
have a more significant oxygen desaturation
More likely to develop pulmonary hypertension
CO2 retention due to hypoventilation Decrease in O2 levels are very
evident on PSG
The COPD patient
Obesity Hypoventilation Syndrome
Also known as “Pickwickian Syndrome”
Increase in CO2 during sleep (>10mmHg)
BMI usually greater than 30kg/m2. No other reason for hypoventilation
such as neuromuscluar disease, restrictive thoracic disease, obstructive lung disease or interstitial lung disease
Retains CO2
Obesity Hypoventilation Patient
Neuromuscular disease Progressive muscle weakness that
increases over time Patient cannot ventilate adequately Example: ALS NIV required to help patient
ventilate Retains CO2
Neuromuscular Disease
Pathology Overlaps coming from the Sleep Lab
OSA Central/ Periodic
SDB
Neuro-Muscular Disorders
COPD – Overlap
Obesity Hypo-
Ventilation
Restrictive Thoracic Disorder
Complex SDB
How do we help patients to breathe when they cannot?
Average Volume Assured Pressure Support (AVAPS)
Acts primarily as a bilevel pressure support ventilator that is able to provide a constant tidal volume
Automatically adjusts the pressure support level to maintain a consistent tidal volume
IPAP will automatically increase or decrease to maintain set tidal volume
Volume targeted Pressure Ventilation
Progressive Ventilatory Insufficiency Neuromuscular Disease Amyotrophic Lateral Sclerosis COPD
Positional Compromised Ventilation Obesity Hypoventilation Syndrome
How AVAPS works
The AVAPS Initial Settings
Parameters Range
EPAP Start low. Adjust for Apnea
IPAP min 4 above EPAPIPAP max 10 above IPAP
minTidal Volume 8ml/kg IBW. Use
chart
Titration Method for Patient on BiPAP AVAPS
Continually assess ventilation through the following areas: Respiratory Rate Tidal volume (ratio between EPAP and IPAPmax but must have
a large enough delta between IPAPmin and IPAPmax to maintain)
CO2 levels*
Continually assess oxygenation through SaO2 EPAP settings
Try to maintain baseline CO2 levels throughout the night if possible
* If applicable
Be Patient! Break old habits!
AVAPS Strategy Be patient! Titrate EPAP to
overcome obstructive apnea
Set Tidal Volume properly
Monitor patient and document
Control leak
Two Different patient groups
Absolute Hypoventilation patients
AVAPS Overlap disease Neuromuscular
disease OHS
Central Sleep Apnea
Periodic Breathing
Idiopathic CSA Complex CSA Servo
Take Away Points AVAPS- you
must titrate EPAP
Monitor ventilation
IPAP min 4 above EPAP
Must control leak!
Servo- EPAP is auto titration
Be patient! PS min is 0 Must control
leak!
You might be feeling like this..
Resources Brian, Jerry,
Tom, Jeff Andrew and Ben
Matt, Brian, Dax Mark, Tom,
Darryl The TEXAS
team!
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