QoW 2015 – 001 (REALLY understanding a patient using NAVA’s Edi signal).

2015 nov - NAVA - 7 novel cases - j 013

I have heard a  lot of people (if not everyone I have known) tell patients “it is really hard breathing thru that small tube (i.e. ETT) but hang in there and we will have that tube out in a little bit”.

Using the graph of Edi, explain why breathing thru the ETT is actually easier than post extubation.

Hint : compare #3 vs #5 (the assumption is that the higher the microvoltage that the brain sends down to the diaphragm, the more distressed the brain “feels”).

Good luck !

Looking forward to the answers.

(As of Sunday, 11/7, we are starting our first giveaway! Please respond to this week’s QotW here on the post. As long as we get 20 or more responses by next Sunday we will randomly draw a winner. Prize to be announced this week! Sorry, we can only ship within the U.S.A., but please answer the question anyway!)

NAVA – historical trend

2015 nov - NAVA - 7 novel cases - j 013

The trend feature offers a historic trend of Edi (EAdi), electrical activity of the diaphragm.

EXTEMELY valuable tool to understand trend of pulmonary related neural activity.

The Edi trendline (to be discussed in detail later) demonstrates brains comfort level during :

  1. SIMV-VCV.
  2. PSV.
  3. T-piece trial.
  4. post extubation.
  5. pulmonary hygiene therapy instituted (includes proper positoning, NT suctioning & BiPAP).

NAVA – real time output

2015 nov - NAVA - 7 novel cases - j 012

Traditionally, ventilators offered real time output of Pressure, Flow and Volume.

Now ventilators with NAVA capability (software download required) offer a REAL TIME  Edi (or EAdi – aka electrical activity of the diaphragm) read as units of microvolts.

Benefit of real time output : INCREDIBLY useful to assess a patient’s brain’s response to EVERYTHING going on as the brain perceives all input signals.

Triggering – neural (NAVA)

2015 nov - triggering - neural

Neural triggering (new triggering – mechanism of action) – very oversimplified explanation.

Brain receives a multitude of inputs (ex: pH, PaO2, carotid body sensors, stretch receptors, etc.)

Brain sends a composite signal (final summation signal) down the phrenic nerve.

NAVA catheter picks up final summation signal (Edi or EAdi – aka electrical activity of the diaphragm).

An Vt (tidal volume) proportional to the Edi is delivered.

Net result : improved patient control of breath and improved patient-ventilator synchrony.

 

Triggering – pneumatic

2015 nov - triggering - pneumatic

Pneumatic triggering (traditional triggering – mechanism of action) – very oversimplified explanation.

Brain receives a multitude of inputs (ex: pH, PaO2, carotid body sensors, stretch receptors, etc.)

Brain sends a composite signal (final summation signal) down the phrenic nerve.

Diaphragm receives signal and starts contracting.

Diaphragmatic contraction results in an increased intrathoracic volume and a relative decrease in intrathoracic pressure.

The releative decrease in intrathoracic pressure results in the ventilator assuming a breath was taken and delivers the preset Vt (tidal volume).

Respiratory Therapy – images of the past

2015 nov - mech ventilation - iron lung ward

It is very important to know where our profession came from.

Although we can look laughingly at the images, we have to consider the advances made and when they were made to understand how we got to our modern day practice.

And then we can also understand the strides need to be made to move us forward and into the future of our practice.