david wolfe crouse hospital upstate medical university technologies handout... · alphabet soup...
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OHS Criteria
Chronic daytime hypercapnia (PaCO2 >
45 mm Hg)
in obese patients (BMI > 30 kg/m2)
after ruling out any other causes of
hypoventilation
OHS Signs and Symptoms
Hypoxemia
Dyspnea
EDS
Morning headache
Depression
As many as 90% of OHS patients also
have OSA.
Rise Time
Time it takes to change from the
expiratory pressure setting to the
inspiratory pressure setting.
iVAPS
intelligent Volume-Assured Pressure
Support
“Under-achievers”
Targets alveolar ventilation by adjusting
to patient’s RR and adjusting PS.
iVAPS - Alveolar Ventilation
Targets and maintains alveolar ventilation instead of ṼE or VT
Delivers required ventilation at the alveoli (gas exchange) ○ Compensates for the air that travels through the
conducting airways
Maintains VA with fluctuating RR ○ Normal anatomical deadspace ~1/3 (?) of VT
○ With respiratory disorders, as RR ↑, wasted deadspace volume ↑
○ Estimating anatomical deadspace maintains consistent ventilation at the alveolar level, even with RR fluctuations
iVAPS
Rate and alveolar ventilation targets are
set for the patient
Responding to the patient’s breathing
changes, it automatically adjusts
pressure support
Provides an intelligent back-up rate
Helps reduce the need for frequent f/u
iVAPS
Set-up manually or “Learn Targets”
(learned during set-up) feature
Learned/Set Target Patient Rate =
Spontaneous Respiratory Rate
Learned/Set Target VA (height) =
Required VA
iVAPS constantly monitors & estimates
pt’s VA in relation to target VA ventilation.
Maintains stable VA automatically during
changes in respiratory mechanics (i.e.
REM sleep transition, postural change).
BiPAP AVAPS
Average Volume Assured Pressure
Support
Increases pressure quickly to maintain
target VT, but slow enough to keep
patient asleep.
Averages VT and
changes PS
gradually (several
minutes).
AVAPS
Automatically adapts to changing patient
needs and disease progression
Maintains optimal patient comfort
Improves efficacy of ventilation
AVAPS
Digital Auto-Trak Sensitivity algorithm:
Allows clinicians to achieve optimum
patient/ventilator synchrony.
Recognizes & compensates for leaks
Automatically adjusts its variable trigger and
cycle thresholds
AVAPS Settings
Target VT set to ideal body
weight – 8 ml/kg
Set IPAP limits
Max: 25 cm H2O (depends on pt pathology)
Min: EPAP + 4 cm H2O
Set RR: 2-3 BPM < resting RR
Set Ti
Adjust rise time for pt comfort
AVAPS
As pt effort decreases, PS increases to
maintain target VT.
IPAP level will not rise above IPAP Max.
As pt effort increases, PS decreases.
IPAP will not fall below IPAP Min.
Trilogy
AVAPS AE
Forced oscillation technique
AVAPS rate
Dual prescriptions
Passive (AVAPS) or active exhalation
port
For OHS
BPAP and AVAPS improved:
Oxygenation
Sleep quality
QOL
AVAPS – greater improvement in
ventilation than BPAP.
Storre et al, Chest, 2006
OHS. Compared to BPAP . . .
Nocturnal ventilation with AVAPS,
lowered TcCO2 by 3 mmHg.
AVAPS:
Impaired sleep quantity and architecture.
Subjectively poorer sleep.
Janssens et al, Respir Med, 2009
Adaptive/Automatic Servo
Ventilation
“Over-achievers”
Treats: CSA
Complex SA
Mixed apnea
Periodic breathing
How: EPAP - keeps airways open
PS – increases VT
(IPAP = EPAP + PS)
AirCurve™ 10 (VPAP Adapt SV)
90% of recent ventilation.
Automatically adjusts PS.
Min PS and Max PS restrict PS range.
EPAP adjusted to eliminate OE’s.
Mandatory breaths delivered at pt’s
recent spontaneous breath rate:
timed backup rate automatically
calculated to match pt’s needs.
ASV Auto
Automatically adjusts EPAP.
Analyzes the state of patient’s upper airway on a breath-by-breath basis.
Min and Max EPAP restricts EPAP range.
Delivers (titrates) EPAP within the allowed range according to obstruction degree.
EPAP changes based on:
○ Inspiratory flow limitation
○ Snoring
○ OA’s
PS
PS trigger points set automatically,
based on patient respiratory flow
measurement.
ResMed recommends Max PS to be ≥
15 cm H2O.
Backup Rate
Uses breath phase mapping.
Provides a timed backup rate
synchronized with pt’s breathing.
If deviation from the target ventilation:
First, adjusts PS.
Second, if necessary, adjusts backup rate
○ From a backup that matches the pt’s recent
rate,
○ Towards the built-in 15 BPM default backup.
Ramp
Set at 5 - 45 min
ASV
Start EPAP to set EPAP
Min PS to PS range (Min PS and Max PS)
ASVAuto
Start EPAP to Min EPAP (EPAP range)
Min PS to
PS range
BiPAP autoSV
Targets peak flow (over time period):
Flow = Volume/Time
Hypopnea/apnea, pt flow decreases . . .
device flow increases.
Increases flow first, then backup rate.
BiPAP autoSV Advanced
Auto EPAP
Automatically distinguishes between clear
airway and obstructed apneas.
Advanced backup rate
Timing of backup rate delivery calculated to
encourage spontaneous breathing at pt’s
own natural rate.
Synchronous with pt’s breathing.
BiPAP autoSV Advanced – cont’d
Servo Ventilation algorithm
Monitors peak flow & Δ’s PS “breath by
breath” to stabilize breathing pattern.
Establishes a target peak flow.
Rapidly normalizes unstable breathing
pattern.
BiPAP autoSV Advanced – cont’d
Bi-flex technology
Provides pressure relief:
○ During exhalation.
○ At critical transition points from
Exhalation to inhalation
Inhalation to exhalation.
BiPAP autoSV Advanced –
Suggested Titration Protocol
EPAPmin = 4 cm H2O
4 cm H2O (or pt comfort) – known CPAP < 10
6-8 cm H2O (or pt comfort) – known CPAP > 10
EPAPmax = 15 cm H2O
PSmin = 0 cm H2O
PSmax = 20 cm H2O
Max pressure = 25 cm H2O
Rate = auto
Bi-Flex = to pt comfort
Set It and Forget It?
Increase EPAPmin for obstructive events.
Adjust Bi-Flex and/or increase PSmin for
patient comfort.
Increase PSmax for central events
Inadequate breathing rate?
Set rate to minimum 8-10 bpm or 2 below
resting RR
Set I-time = 1.5 seconds
Wait 20 minutes after change.
ASV – through March 2015
CSA/CSB due to HF consistently
demonstrated that ASV decreases CA
frequency.1,2,3
ASV improved LVEF.1,4
ASV impact on mortality and QOL
uncertain (not been studied).
1. Pepperell et al, Am J Respir Crit Care Med, 2003
2. Oldenburg et al, Eur J Heart Fail, 2008
3. Fietze et al, Sleep Med, 2008
4. Sharma et al, Chest, 2012
May 2015 press release
Cautioned against ASV use in pt’s with
symptomatic chronic HF & LVEF ≤ 45%.
↑ risk appears to be in LVEF < 30%.
EPAP not adjusted much – not a lot of
obstruction.
EPAP was not auto.
No difference in exercise capacity or
QOL.
Confusing?
Present settings:
EPAP = 8 cm H2O
IPAPmin = 10 cm H2O
IPAPmax = 25 cm H2O
New settings to EQUAL present settings?
EPAPmin
EPAPmax
PSmin
PSmax
Max pressure
Confusing? No!
Present settings on ASV:
EPAP = 8 cm H2O
IPAPmin = 10 cm H2O
IPAPmax = 25 cm H2O
New settings to EQUAL present settings?
EPAPmin = 8 cm H2O
EPAPmax = 8 cm H2O
PSmin = 2 cm H2O
PSmax = 17 cm H2O
Max pressure = 25 cm H2O
Quick Takeaways
AVAPS targets TV
iVAPS targets VA
AVAPS AE has auto-EPAP
i/AVAPS - underachievers
ASV – overachievers
ASV Auto – tracks (minute) ventilation
BiPAP AutoSV – tracks peak flow