Pt getting better strats (Mod 4) Flashcards by Derrick Chuong

Why should we titrate to the patients WOB if they’re getting better?

To promote patient/ventilator synchrony
Support muscles of ventilation (based on patient/vent work)

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What is tube compensation?

When the ventilator nullifies the resistance imposed by the airway via ETT

similar to PS, Inspired pressure is used to compensate for imposed WOB

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How are time constants affected by tube compensation?

TC varies the pressure depending on the tube size and Pt inspiratory flow

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How is Tube Compensation calculated?

Ptrachea = (Paw - Ktube) x Flow^2

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What are benefits of tube compensation?

Increase patient comfort over Psupport

could indicate readiness for extubation
Reduce risk of air trapping caused by expiratory resistance (some allow insp and exp comp)

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What settings are required for tube compensation? (ATC mode)

Type of airway (ETT vs Trach)
Size of airway
% compensation (0-100)
Inspiratory and expiratory or inspiratory or expiratory only (set up configuration)

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What is Tube compensation mode on the Evita?

Automatic tube compensation (ATC)

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What is Tube compensation mode on the Hamilton G5?

Tube Resistance Compensation (TRC)

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What is Tube compensation mode on the GE?

Airway Resistance Compensation (ARC)

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What is Tube compensation mode on the PB 840/980?

Tube compensation (TC)

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What does Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive) do?

A mode that guarantees a min MV even though a Pts spontaneous ventilation may change.

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In Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive), what happens if the patient maintains a MV above the set MV?

Then the mode functions like CSV-PS

all breaths are supported breaths

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In Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive), what happens if the patient MV falls below the set MV?

Mandatory breaths will be delivered (at the set Vt) to makes the total MV = set MV

Only the M breaths required to return the Pts MV to the set MV

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How does Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive) differ from SIMV?

SIMV will always provide the set number of mechanical breaths a minute, regardless of the patients spontaneous MV

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what does the number of M breaths per minute depend on in Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive)?

How much the patient is breathing own their own

assisted breaths are technically possible if the pt made an inspiratory effort during the window

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What happens in Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive) if the patient becomes totally apneic?

They will get mandatory breaths at the set rate

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What breath types are delivered in Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive)

All breath types (M,A,S), but usually only mandatory and spontaneous supported are seen.

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In Mandatory Minute ventilation (VC-IMV or PC-IMV adaptive) what happens if the patient makes an inspiratory effort in the trigger window?

The breath is considered to be assisted

What are the goals of Adaptive Support Ventilation (ASV)?

Provide MV while minimizing the WOB and avoiding ineffective breathing patterns

What ineffective breathing patterns does ASV aim to avoid?

Rapid and shallow
Breath stacking
Excessively large breaths
Excessive dead-space ventilation

What is Adaptive Support ventilation (ASV)?

An optimal control type of closed loop mode

Should result in the least amount of WOB and least amount of pressure supplied by the ventilator
a complicated form of MMV basically

What phase variable breaths are delivered if the breath is mandatory?

VC or PRVC

What phase variable breath type is delivered via ASV if the breath is mandatory?

Mandatory breaths in ASV are PC and volume targeted?

What phase variable breath type is delivered via ASV if the breath is spontaneous?

Spontaneous breaths in ASV are Psupp and volume targeted

What are ventilator breaths based on in ASV?

1. Based on operator set % Minute vol 2. Pressure controlled and volume targeted Vent will deliver a mix of PC and PS breaths depending on patients drive to breath

what is set %minvol based on in ASV?

ASV % minvol is based on 100ml/kg IBW for 100% settings (if normal) The following %MinVol adjustments would be made - Normal Pt =100% - COPD = 90% - ARDS = 120%

What do you setup on ASV?

Patients IBW and %min vol

how does hyperthermia affect %MinVol set?

We need to add extra 10% per degree C increase

How does altitude affect %MinVol set?

5% per 500m above sea level

Left off at slide 19

What peak flow is required for a patient with moderate to strong ventilatory demands?

60 L/min or greater

What parameters should be assessed when weaning off ASV? (3)

1. Oxygen and Peep for Oxyegnation 2. %Minvol for CO2 elimination 3. Spon: RSB and %Fspont

When weaning in ASV, how should a SBT trial be conducted?

1. Decreased PEEP to 5 2. Lowering the target minute volume (%MinVol) 3. Reduce Pressure support as needed

What adjustments can be made to pressure support to reduce %MinVol when weaning on ASV?

When performing a SBT, If the pressure support on the current %MinVol setting is higher than 15 cmH2O, the %MinVol setting can be lowered first to 70% and then 25% to reduce pressure support gradually to 5‑8 cmH2O for the SBT.

What is Proportional Assist Ventilation (PAV)?

A PC-CSV Adaptive mode designed to assist spontaneous ventilation - similar to PS but the pressure lvel delivered is variable and proprtional to the patients spontaneous effort. - Harder pt works = more support the vent delivers = **positive feedback** - Less work = less support

How does Proportional Assist Ventilation work (PAV)?

Positive feedback system. - More Pt effort = more support, less effort = less support - Based on equation of motion: **Pmuscle + Paw = (Vt x E) + (Flow x R)**

Proportional Assist Ventilation (PAV) Phase variables

- Trigger: patient only - Limit: Pressure-limited - Cycle: Flow

2 forms of assistance that Proportional Assist Ventilation (PAV) provides

- Flow assist: Helps overcome WOB due to resistance - Volume assist: Help overcome WOB due to elastance (1/C)

What is Proportional Assist Ventilation (PAV) best suited for?

Pts with abnormalities in resistance and compliance - **not** suitable for pts with neuromuscular weakness or CNS depression who cannot generate adequate insp effort

What is Neurally Adjusted Ventilatory Assist (NAVA)

Mode designed to assist spontaneous ventilation. - Similar to PS but the pressure support level delivered is variable and is proportional to the pts spontaneous effort - Uses Edi catheter to support the diaphragm - Like PAV is a positive feedback system

How does NAVA differ from PAV?

NAVA uses a Edi catheter (electrical activity of the diaphragm) to send stronger signals to the diaphragm to breath, which in turn increases support level.

What is Volume support?

A spontaneous mode only (adaptative PC-CSV) can't be added to combined modes like SIMV - Delivers pressure limited, volume targeted breath. - PS level is adjusted breath to breath (all pt triggered) - Works on a negative feedback mechanism (like APV)

Advantages of volume support?

Guarantees tidal volume, pt still determines rate and Ti - considered a self weaning mode