NAVA

Question 1

What is EDI

Answer 1

electrical waveform activity of the diaphragm
–> represents the neural respiratory drive (final output of respiratory centers) as a
continuous function over time

–> has unit of microvolts (μV)

–>determines neural
breathing activity & function of the diaphragm

Question 2

What is the pathway of a volume request?

Answer 2

respiratory center sends a volume request signal via phrenic nerve –> diaphagram–>force of contraction depends on the magnitude of neural signal –> represent on the EDI

Question 3

What is the features of the EDI catheter?

Answer 3

1. has 10 electrodes at the tip of the catheter to measure the movement of diaphragm
2. has a OG or NG port for feeding and medications

Question 4

What is EDI peeak?

Answer 4

the peak contraction of the diaphragm
–> the work of the diaphragm has to
perform for each breath

Question 5

what is edi min (baseline)

Answer 5

diaphragm at rest, should be around 0

Question 6

What is EDi baseline like in infants

Answer 6

varies–> they have hard time to maintaining FRC

Question 7

why is the edi baseline elevated in infants

Answer 7

• elevation of the baseline means diaphragm is more tonic and contracted even at rest
• this helps to maintain the negative pressure and FRC

Question 8

what does it mean when EDI peak is out of range

Answer 8

patient is using more force to breath, indicating increase WOB

need more support

Question 9

What does it mean when EDI peak is low ?

Answer 9

Hyperventilation-overventilation–>fatigue
Sedation
Neural disorder
Muscle relaxants

Question 10

what causes high peak EDI signal

Answer 10

Increased effort (respiratory load)
Weakness of diaphragm
Pain
Anxiety
Inadequate Peep, derecruitment (Edi
min)
decreased sedation
increased demand for ventilation such as exercise,
and increased dead space.

Question 11

What is the normal EDI MAX RANGE?

Answer 11

5 to 15μV

avg is 10

Question 12

where is the EDI catheter position?

Answer 12

gastro-esophageal junction

Question 13

how to know if EDI catheter is positioned correctly

Answer 13

if the 2nd and 3rd leads are highlighted in pink/blue

Question 14

What is the function of NAV

Answer 14

initiate ventilation as there is diaphragm excitation

delivers ventilatory support:

–> in synchrony with the patient’s neural respiratory drive

AND

–> in proportion to the patient’s neural respiratory drive

Question 15

how is the assist pressure determine in NAVA?

Answer 15

Psupport = (Edipeak-Edimin) x NAVA level

Question 16

What is the unit of NAVA value?

Answer 16

cmh2o/mV

Question 17

What is the edi triggger?

Answer 17

0.5 mv above the edi min

Question 18

when does the expiratory phase start in EDI

Answer 18

70% of EDI peak

Question 19

can NAVA be used invasively and non-invasively

Answer 19

yes

Question 20

What are the advantages of NAVA

Answer 20

• Better patient synchrony with the ventilator
  —>Lower PIP and O2 needs
  • Better sleep quality
  • Brain knows what the body wants at all times
  • Lung protective- decreased risk for barotrauma and volutrauma
  • Less sedation is needed and patient is more comfortable
  • Assess proper PEEP levels
  • Diaphragm atrophy/dysfunction is reduced
  • Better able to assess patients WOB post-extubation

Question 21

What other backup setting is needed for NAVA

Answer 21

pressure support
–>PS above PEEP

Backup ventilation
–>PC above PEEP

Question 22

What could be the possible cause of absence or lower edi siggnal

Answer 22

High Sedation level
Patient over assisted
Edi catheter out of position
Phrenic nerve injury

Question 23

what are the NAVA settins

Answer 23

Edi Trigger (microvolts)
 NAVA Level
 --> cmH2O / microvolt
 PEEP
 FIO2

Question 24

What happen to the Edi when there is disease in the lung or respiratory distress

Answer 24

EDI increase because brain will send more signal to the diaphragm to generate a bigger breath

Question 25

How to adjust NAVA level based on Edi signal?

Answer 25

increase EDI –> increase NAVA

• ->increase EDI means patient requires more breath
• ->increase NAVA to assist patient

Decrease EDi–>decrease NAVA

• -> decrease EDi back to baseline is because patient is healing
• ->decrease NAVA to balance patient effort