1. Neurally Adjusted Ventilatory Assist
Jennifer Tronson
VVC RSPT 233
10/10/2015

2. How Do We Inhale? Diaphragm drops Thoracic cavity expands
Pressure drops
Negative Pressure Gradient is formed from the mouth to the alveoli
Air flows in and down the pressure gradient until equilibrium is reached

3. How Do Ventilators Know When a Patient Wants to Take a Breath?
Diaphragm drops
Thoracic cavity expands
Pressure drops
Negative Pressure Gradient
is formed from the mouth
to the alveoli
Air begins to flow down the
gradient
The ventilator is triggered to deliver a breath by settings predetermined by the therapist or a measurement taken of previous breaths
Or….

4. How Do Ventilators Know When a Patient Wants to Take a Breath?
Water in the tube alters the
pressure or flow
Patient movement triggers
a breath
No breath is delivered because
the patient is unable to alter
flow or pressure enough to
trigger the ventilator
Even if everything works according to plan there is a significant delay between the patient’s brain deciding it should take a breath and the ventilator delivering the breath

5. How Does Our Body Know We Want to Take a Breath?
The respiratory center responds to chemo and pressure receptors in the body and sends a signal through the phrenic nerve to the respiratory muscles to contract and expand the thoracic cavity.

6. Is There a Better Way?
What if the ventilator could be triggered by the same signal that triggers the respiratory muscles?
Increased patient synchrony
Increased patient comfort
Potentially lower levels of sedation
What if that signal could also tell the ventilator how much support is needed for each breath?
Support will be calculated based on the signal the brain sends to the diaphragm so there will not be a lack of support if the patient is requiring a deeper breathe nor too much support if the patient is trying to take a smaller breath.

7. NAVA - Synchrony Redefined

8. Triggering Comparison

9. NAVA Neurally Adjusted
Utilizes a catheter to detect the electrical activity signaling in the diaphragm Edi
Uses the strength of the Edi to determine how much assist to deliver to the patient
Bases each breath on the electrical signal, not trending from previous breaths

10. NAVA Ventilatory Assist
The signal from the Edi catheter is used to determine the amount of support supplied and when the support is supplied.
The support is provided in the same fashion no matter the means of delivery to the patient (Invasive or Non-Invasive), and is unaffected by leaks as the breath is cycled on and off by neural signal not preset volume or pressure.

11. NAVA Ventilatory Assist
The support is supplied in synchrony and proportion with the Edi signal
The amplification applied to this support is the NAVA level NAVA level X (Edi signal-Edi min)+PEEP

12. Synchronized Ventilatory Assist

14. Background NAVA is a system that belongs to MAQUET
It is compatible with the SERVO- I ventilator
Has been available in the US since late 2007
The largest adopter of the technology in Southern California is Loma
Linda, but it is also used in
Kaiser, Children’s Hospital
of Orange County, and newly
in the Huntington Hospital

15. Background
In the US it is primarily used in NICU/PICU, though in Europe it is widely used in adults.
This is attributed to the obvious “ah-ha” moment that happens when you switch a baby over to NAVA and see them stop fighting the vent, relax and succeed on lower pressures and lower FiO2s
Several factors have attributed to its slow adoption in adult markets in the US, Drs and therapists not wanting to relinquish control, learning curve, inertia…

16. Background

17. Setup - Select the appropriate Edi Catheter
Edi catheter ‘s differ in iED making them uniquely suited to patients based on height.
Only the 12 and 16 Fr sizes have a lumen for evacuation

18. Setup – Perform Edi Module Function Test
Insert the Edi Module into the SERVO-I
Connect the Edi Cable to the Edi Module
Perform Edi Module Function Test

19. Setup – Position the Edi Catheter
Measure NEX & Calculate Insertion Distance

20. Setup – Position the Edi Catheter
Inspect the catheter
Put the tip in sterile water – no other lubricant
Allow the tip to remain in the water for 5 seconds before removing

21. Setup – Position the Edi Catheter
Insert the catheter to the Y value determined earlier
Connect the catheter to the Edi module

22. Setup – Verify the Catheter Position
Once you verify that the 2 middle rows are highlighted in blue note the insertion depth and secure the catheter in place.

23. Setup – Monitor the Edi Signal
Edi signal can be seen in all modes including standby
Edi Peak and Min are available for each breath cycle
Signal trending for 24 hours are available

24. Setup – Set the Initial NAVA Level
Open the NAVA preview window with the Neural Access key
Set the initial NAVA level to achieve the same or slightly lower pressure level that is currently being delivered to the patient
Press the NAVA level key then use the rotary dial to adjust the level

25. Setup – Select and Set NAVA Mode
Utilize the calculation to compare your pressure levels

26. Setup – Select and Set NAVA Mode
Set PEEP
Set FiO2
Set Trigger Edi
This detects increases in Edi and should be set to filter out background noise so that it does not affect the patient’s ability to trigger a breath

27. Setup – Select and Set NAVA Mode
Set Pressure Support above PEEP
Must be set low enough to not induce hyperinflation and interfere with the Edi signal
Set Backup Ventilation
This is AC/PC mode that is utilized if the patient becomes unable to signal for a breath

28. Setup – Select Alarm Limits
Set Alarms that are adequate for the patient and in line with your facilities alarm limit policies.

29. Set Up Video

30. Weaning
Titrate NAVA level to obtain Edi Values that are 60% of the Edi max value during the SBT.
Repeat at least once daily
Extubate when SBT is successfully tolerated for 2 hours

31. Contraindications
Any contraindications for naso-orogastric feeding tube such as upper airway surgery and skull base fractures
NAVA would not be appropriate for a patient exhibiting an undesirable breathing pattern such as Biot’s breathing though the Edi information may remain a useful tool
Known phrenic nerve lesions
Severe hiatal hernia
Need for MRIs as the Edi catheter is not approved for use in MRI environments
NAVA may be contraindicated in a patient that is experiencing seizures or frequent panic attacks that alter the normal breathing patterns

32. Works Cited http://ww2.maquet.com/uk/product/NAVA?tab=Features