1. Drager Evita Mechanical Ventilators

2. Evita 4 Reading Read pages 447 - 464 in Cairo
Complete the review questions on pages
Website below on Web CT as a link  
You should also be familiar with the Drager Evita 2 ventilator
This is used clinically at some sites in CHA
The Evita 2 will NOT be tested in this course
Page 447
There are multiple generations of Evitas out there: 2, 4, XL and now the Infinity V500. At the same time, PB has come out with one ventilator, and Maquaet has one as well. Draw your own conclusions.

3. Basics of Evita XL
Microprocessor-controlled, electrically and pneumatically-driven
Flow and time are manually triggered

5. Modes of Ventilation CMV (A/C volume) APRV
SIMV (Volume with or without PS)
PCV + (SIMV PC)
PCV + Assist (PC A/C)
PSV or CPAP
MMV (With or without PS)
APRV
Neoflow
ILV
PPS (Not approved in Canada)
The PCV thing is very confusing.
Make sure at some place that it is mentioned that PCV is not peep-compensated; they have added the ability to “attach” the 2 pressures together but this creates other problems.

6. External Flow Transducer
Heated wire transducer
DO NOT poke pencils, fingers, etc into the sensor!
Must be changed with each change in pt
Must be recalibrated with each change using “device check”
Only needs to be changed if there is no filter prior to it.
Using a heated wire filament, the vent measures the current going to it to keep it at a set temperature. As flow increases, the filament tries to cool, or in reality stays at the same temperature but needs more electricity to maintain temperature, so the vent measures the change in current to measure flow.
They frequently break down, and may need to be calibrated frequently.

7. Ventilator Checkout Device does a series of self-tests when turned on
Still requires “device check” to be done in-between pts, and any time the circuit or flow transducer has been changed
Once ventilator is in ‘stand-by’, choose ‘check’ from the tabs and then do the device check

9. Ventilator Checkout Follow the instructions on the screen
Pay attention to these instructions!
Instructions are found on the top of the screen
If Neoflow sensor is NOT attached, this section will fail and you will be required to redo the procedure, so be sure to choose ‘next test’
Don’t forget to do both sections – Device and airtight check
There is a ‘cork’ built into the stand of the Evita when doing the pressure-testing sections of the device check
Two tests! Both have to be done, or the vent is not safe to use. One test is a circuit test for leak and compliance. The other is a device check that checks out the internals of the machine.

10. Alarms Three levels of alarm conditions
Warning (High priority)
Caution (Medium priority)
Advisory (Low priority)
Tonal quality of the alarms change depending on the level
Unable to pre-silence critical alarms
Follows ISO:9000 protocols
EXCEPTION – Suction procedure in the XL
ISO 9000? Take out in future

11. Alarms
Medium- and low-priority alarms do not need to be acknowledged by operator
High-priority alarms require the operator to press “alarm reset” on the screen and then hit the dial to verify that the problem is resolved

12. Available Controls
Only controls active in the selected mode are active
To change modes, select tab-adjust settings and then hit the dial button to apply
To access other modes, select the ‘More’ tab and choose the other mode that you would like

14. Autoflow
Autoflow is similar to PRVC on the Servo Vents and VC+ on PB 840
“Target” volume ventilation with a pressure breath
Alters function of insp/exp valves, allowing pt to receive whatever inspiratory flow they want (up to 180 L/min)
Pt can breathe spont. at any time of Ti and Te due to active inhalation and exhalation valves
Available in all volume modes
Allows for ‘active inhale and exhalation valve’
If pt coughs or breathes during set inspiration, expiration valve allows pt to inhale/exhale while maintaining inspiratory/expiratory pressure
Uses the concept of an “open” or active exhalation valve, where the valve isn’t closed but is continually adjusted to maintain the set pressure in the circuit.
There is version of PRVC that works on a feedback loop, gives a pressure breath, and adjusts that pressure breath-by-breath to target a set Vt. So flow is partially patient-determined, and varies both throughout the breath and breath-by-breath.
Patient can’t breathe spontaneously in exp, or it would trigger a breath.

15. Autoflow When pt does more work, ventilator does less work
Same concerns as with Servo 300
Pages 473 and 474 Mosby’s Equipment
NOT A CONCERN – Take out for next year, this doesn’t make clinical sense!!!!

16. Autoflow
To access, touch ‘additional settings’ button once your basic settings are entered
Then touch ‘autoflow on’ button
Press rotary knob to confirm this is what you want to do
When initiated, vent delivers volume-targeted breath with a pause
Plateau pressure is measured
If autoflow is off, it is a strict, square-flow waveform volume breath. This is confusing because you can set VT, flow, or Ti. So if you increase flow, the vent inserts an insp pause. How to fix: Shorten Ti as low as the vent allows it, or don’t use such an antiquated mode!

17. Autoflow Unit uses plateau pressure as baseline to start from
After first test breath (volume), vent delivers pressure breath at plateau pressure
Volume delivered is measured
Adjustments to ventilating pressure +/- 3 cmH20 to ‘guarantee volume’ delivered
High pressure limit 5 cmH20 below high pressure alarm
Alarms ‘volume not constant’
So adjusts by up to 3 cmH2O breath-by-breath to deliver volume.
The high pressure limit is so the patient still ventilates if alarm is hit, just at a lower pressure level.

18. Pmax - Auto-flow off Pages 474 - 475 Mosby’s Equipment
Also known as Pressure Limit Ventilation
Biggest difference is that the exhalation valve is closed in this setup where with autoflow, it is open
Not difficult to discern which the manufacturer (and probably the patient!) recommends!
There is a limit that you can set in traditional volume ventilation that limits the pressure delivered in the breath, and prevents the pressure going above but still allows some ventilation.

19. PCV+Assist vs. PCV+
Pressure-control ventilation in the Evita is termed PCV Assist
SIMV pressure control in the Evita is termed PCV+
Spontaneous breaths can be pressure-supported
Confusing, but the manufacturer doesn’t want to change it so that it is more logical.

20. PCV+Assist vs. PCV+
Ventilating pressure is equal to set inspiratory pressure (not above PEEP) for PC mandatory breaths
In this case, increasing PEEP without increasing ventilating pressure will decrease tidal volume.
Pressure-supported breaths are set with pressure above PEEP
Increasing PEEP in PS breaths will not affect tidal volume (assuming CL stays the same)
So not PEEP-compensated!

21. PCV+Assist vs. PCV+ Rise time used to adjust flow for pt comfort
It affects both mandatory and PS breath delivery
Pressure rise represents amount of time it takes the ventilator to achieve set pressure
Adjustable from 0 to 2.0 seconds
Apnea ventilation can be on during PCV+ as there are spont. breaths, but not during PCV+ assist

22. PCV + Assist ‘Quirks’ Two options available (See video)
Link Pinsp and PEEP
Press either Press button and then press Link Pinsp and PEEP
Keeps delta P the same
I:E constant – Can lock in I:E ratio
Press Ti or RR and then press I:E constant
Then Ti or RR will change accordingly depending on which needs to be changed
Their way of attempting to overcome the fact that it is the only ventilator that is not PEEP-compensated in PCV. Be wary if you link and then try to change PC, as it will only increase PEEP.

24. Pressure Support Can set PS levels as desired
Or set PS to 0 to achieve just CPAP
PS levels are above PEEP
Rise Time Control becomes active
Flow cycle is 25% of peak flow for adults and pediatrics (6% in neonates) or an insp. time exceeding 4 sec.
Remember to set apnea parameters in this mode
Doesn’t have a set exp flow cycle option where you can control cycle.

25. APRV Settings similar to other ventilators offering APRV
Peep high
Peep low
Time high
Time low
Rates are based on time high and low
No PS can be set, but can set TC
Slope also available

26. Automatic Tube Compensation
Software update; not a mode but an adjunct
Compensates for Raw associated with artificial airways
Can be used with all modes of ventilation and airway sizes for neo/ped/adults

27. Automatic Tube Compensation
Found in ‘additional settings’ during vent setup
Tube size –
ETT or Trach type –
Comp%
Comp on/off
Why only ETT or trach? Why not tube length?

28. Automatic Tube Compensation
Pressure is  during insp and  during exp to overcome resistance
Expiratory portion can be disabled
*Caution for COPD pts – The exp portion may need to be disabled as their small airways may be kept open due to ETT resistance
*Caution – Adding ATC to another mode may result in over assist
*Caution – ATC will not compensate for secretions in artificial airway
Mathematical equation for calc of tracheal P to allow this adjunct to function – pg 479 Box Mosby’s
The goal is to overcome the WOB generated by having an artificial A/W in place: This is resistance to flow. So what is the resistance of the normal upper A/W? This can lead to confusion in weaning; should be able to be at 100% and wean PSV to 0, but what if it’s at 75%?

29. MMV Mandatory Minute Ventilation
Set Vt, Ti, RR, Slope, PS, FiO2, PEEP
ATC, trigger, and autoflow available
Pt can breathe using user-set PS or just CPAP
Set minute volume is guaranteed by monitoring the pt’s spont. minute volume; ventilator will add supplemental breaths as needed to achieve set minute volume
Important to set high RR alarm to stop rapid shallow breathing that might meet goal MV
Why would you use this mode? How would you use it? Pt population, or should you use it on everyone? Problems associated? How about pt riding the backup rate; how can you tell if they are actually breathing spont. or letting the vent do the work?

30. PPS: Proportional Pressure Support
Similar theory but not as sophisticated as PAV+ on the PB840
The more the patient inspires, the more support the ventilator provides
Pt must have adequate ventilatory drive
Circuit (incl. pt!) must not have any leaks!
User sets flow assist, which overcomes resistance; and volume assist, which overcomes elastic lung properties
Still on some ventilators, but the approval certificate lapsed in Canada therefore it is illegal to use
On our vent, but not on vents clinically. Don’t know much about it as to whether it is/could be valuable. Maybe just another failed superior weaning mode (It’s very hard to prove that one advanced mode is better than another as so much depends on RT comfort and ability).

31. Apnea Ventilation
Supplies volume ventilation with set rate and tidal volume if pt becomes apneic in any of the following modes
SIMV
PCV+
CPAP
APRV
PPS
To set apnea parameters, touch ‘additional settings’, then ‘apnea vent’’
Set Vt and RR
Apnea time interval is set under normal alarm settings
Be very careful when setting it in modes that have control settings: Your pt shouldn’t be going apneic. You want them in your mode, not a controlled apneic mode.

32. Special Procedures Three tabs Additional functions
Insp. hold and Exp hold
Nebulizer
Suction procedure

34. Special Procedures Diagnostics P0.1 Peepi NIF
Negative Inspiratory Force
Used to assess muscle function
Considered a ‘weaning number’
PEEPi is intrinsic peep, or autopeep.
P0.1 is a weaning assessment tool, not widely used.
Where do I talk about weaning numbers?

36. AutoPEEP measurements
Pt must NOT have any inspiratory efforts during this time
Select ‘Diagnostics’, then PEEPi and start
Procedure performed automatically
Screen will display PEEP(set), PEEPi, trapped volume AND previous numbers
This is an ‘estimate’…
This is an estimate? Take out for next year.

37. Occlusion Pressure
P 0.1
Used to evaluate patient’s neuromuscular drive for weaning
Will be explored more in Critical Care II next semester
Know how to access

38. Odds and Ends Nebulizer Built-in
Press soft pad until light stops flashing and becomes solid (About 3 seconds)
Neb runs for 30 minutes
May affect measured volumes as flow transducer is ‘hot wire’, and may cool with exhaled aerosol
May affect? Think about the non-exhaled gas that gets sent there flushed through the circuit by bias flow. All gas should be filtered before going to environment; the easiest place should be before the exhalation valve.

39. 100% Suction Must be pressed for > 3 seconds
Lasts for 180 seconds (Counts down at top of screen)
Low exhaled minute volume alarm is disabled during this time
After this period, oxygen is delivered at 100% for 2 more minutes and alarms are reactivated in Adult Mode
Does this allow for disconnect? Check.

40. Automatic Leak Compensation
Logic circuit allows for compensation in loss of volume due to leaks in circuit
Can cause you grief if trying to measure cuff leak volume before extubation!
Cuff leak volume will be further explored next semester in Critical Care II
To access, press configuration-ventilation-enter 3032-more settings
Not automatically done; you must do it, and then the vent will compensate for it for you.
Take out configuration code – They shouldn’t know this anyway.
Why would it affect cuff leak measurement? Ask Leah.

41. Flow & Oxygen Monitoring
May have to turn off due to problems with sensors
Always replace with external monitoring device
To access, press alarm limits and then monitoring
Shouldn’t turn flow monitoring off! O2 monitoring maybe and then add external, but a vent without flow monitoring is critically dangerous and must be taken off pt and serviced.

42. ILV Two ventilators (both same Drager variety) can be ‘slaved’
Via analog interface to ventilate one lung independently from the other
For pts with severe unilateral lung disease
Bronchopleural fistula
Bronchopulmonary hemorrhage
Unilateral pulmonary surgery
One vent is master, the other slave, meaning that the one matches the rate of the other so you don’t have dys-synchronous chest movement. We don’t know if this really makes any difference; these pts are sick enough that we can’t really study to see what is the best way of doing things.

43. Trigger Sensitivity Flow sensitivity (Unless flow monitoring shut off)
Don’t forget to set sensitivity – So do not default setting
Only one mode trigger sens can be shut off in (CMV)
Pt cannot trigger mandatory breaths (no backup pressure sensitivity)
Pt can breathe spont in-between mandatory breaths
Essentially control mode
Flow monitoring shouldn’t be shut off.
Explain last 2 lines, change for next year.

44. Evita XL stuff O2 therapy Non-invasive
For use with the Opti-flow system
Set FiO2 and flow
Access from ‘Stand-by’
Must disconnect the exhalation limb of the circuit
Handy: can go from BiPAP, to invasive, to O2 therapy.

46. End Tidal CO2 Calibration depends on device used
Reusable – Calibrate on the CO2 attachment on the XL machine
Disposable – Calibrate with device attached
Confusing, explain better, change for next year.

47. End Tidal CO2

48. Sigh Procedure Essentially a mini-recruitment procedure
Set the PEEP that you wish to increase to for 2 consecutive breaths every three minutes
Operates only in CMV modes
Found under ‘additional settings’
OMG

49. Suction Procedure Different than 100% suction button
Similar to the Servo i
Allows for open suction procedure
180 seconds of pre-oxygenation
Disconnection allowed for 120 seconds
Once reconnected, post-oxygenation is for 120 seconds
Move to 100% O2 section for next year.