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How to improve Efficiency of ventilation and
Comfort of patient?
AVAPSTM Feature
More about the Algorithm
Efficiency
Comfort
Safety
Versatility
Prediction
AVAPS Algorithm
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Estimation of Vte at each breath (Auto-TRAK)
Comparison of the averaged Vte with target Vte
Calculation of the pressure to add to reach the target Vte
Progressive increase of the IPAP (< 1cmH2O/min) from breath to breath
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If the patient is unstable: the IPAP cannot change by more than 0.5 cmH2O/min
If the cycle is not « regular » (sudden leak increase or decrease, patient sigh, the
patient talks ..etc), it is not taken into account: constant IPAP
Starting pressure support (starting point) = Target Vt / (60 ml/cmH2O)
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IPAP min
IPAP max
Target Vte
Alarm
From EPAP to IPAP max
From IPAP min to 30 cmH2O
From 200ml to 1500ml
Low Vte (can be disabled)
Vte Estimation
Exhaled patient tidal volume is estimated at each breath
Flow
Inspiratory
Phase
Vti
Vti
Vti
Zero Patient
Vte
Vte
Expiratory
Phase
1
Vti > Vte
Vti – Vte = ∆ Leaks > 0
2
Vti = Vte
Vti – Vte = ∆ Leaks = 0
Vte
3
Vti < Vte
Vti – Vte = ∆ Leaks < 0
Time
Pressure Support Calculation
For Each Breath
Elastance
Missing Vte
PS of that breath
Target Vte – Estimated Vte
Vte of that breath
PS to add =
New PS =
Average missing Vte x Average Elastance
PS of that breath + PS to add
Breath to Breath, Pressure Support Changes
IPAP Max
< 1 cmH2O/min
IPAP Min
EPAP
Target Vt
Vte = Vt patient
Example
Pressure
Patient flow
 Target Vte = 250 ml
 Measurements:
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Measured average PS = 6 cmH2O
Estimated average Vte = 220 ml
 Calculation:
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Missing average Vte = 30 ml
Pressure to add = (6 / 220) x 30 = 0,8 cmH2O (progressively within the next minute)
New pressure support = 6,8 cmH2O
 Next breath:
‐ Pressure to add = (0,8 x Tbreath) / 60
If Tbreath = 4s then pressure to add is 0,05 cmH2O for a stable respiration and 0,03 cmH2O for
an unstable respiration
Starting Pressure Support
The Synchrony starts the ventilation with a pressure support
of 1cmH20 / 60ml of the set target Vte
Example :
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Target Vte = 600 ml
EPAP = 5 cmH2O
IPAP Min = 12 cmH2O
IPAP Max = 20 cmH2O
Starting point :
‐ Starting Pressure Support = 600ml x ( 1 cmH2O/60ml) = 10 cmH2O
‐ Starting IPAP = 15 cmH2O
Conclusion
 Reliable algorithm based on RI Technology (Auto-TRAK: leaks and
Vte estimation):
‐ Efficient pressure changes based on Vte
‐ Stable algorithm not affected by leaks
 Small and progressive pressure changes that do not deteriorate
patient comfort
 This algorithm allows you to combine comfort of patient with safety
and efficiency of ventilation