Let me reiterate that my working knowledge of the Babylog is very limited.
My understanding of VIVE's POTENTIAL utility is akin to lowering the risetime in PS such that a sufficient VT may be delivered.
Using adult analogy (as I scurry to my better comfort zone)...let's say you have a little ole lady who is pretty sedated on a vent with a number 6 ET tube. She is on PS 10 and breathing at a rate of 18. Risetime is slow (defined by time on Drager or Serov---let's say 0.3 seconds or % on 840--let's say 50%). VT is 400. She is not breathing with a lot of flow demand. Now someone comes up and puts risetime as "aggressive" as can be----0.0 or 100%. Now that PS level is reached before that VT can be delivered--initial flow is real high and (assume similar exp termination critieria) the breath ends before an adequate VT is delivered.
My understanding of the Babylog is that the PSV (without VG) terminates at 15% of the Peak. And that leaks of up to 40% can be factored in.
So using VIVE is akin to then being able to set a lower insp flow in PSV and it being a less aggressive risetime.
A common misconception is that one can use a lower exp flow to minimize exp resistance. But the ET tube is already so resistive.
Let's say you had a baby in PSV mode 15/5. Insp and Exp flow set at 8. You MIGHT see if turning down inp flow to 4 gives a bigger VT without air hunger.
I have also heard virtually everyone say "just forget about VIVE". But as RT's we should at least know the theoretical possibilities. If for nothing else to dazzle or confuse that student.
Ahh just found an old email from Dennis Bing. I assume it's OK, just caveat the ideas expressed don't represent Drager's..
It doesn't make sense to me to use SIMV on Babylog as there is no PS available on spontaneous breaths (I don't even like SIMV on adults when there is PS available). So to me one should use either A/C or PSV--with or without VG.
"As part of the design team for the Babylog 8000 plus software 5, and a long
time Babylog user, I can say this issue of how ViVe is meant to be used has
often been confused.
Some people think to use a lower expiratory (Ve) flow to, as you say, reduce
expiratory resistance and WOB. This stems from a paper titled "Effects of
infant ventilator design on spontaneous breathing." by Bob Kopotic in the Journal
of Perinatology, 1987 7(4): 298- 300. One point of this bench study was to
show that inherent high resistance of the expiratory valve in some infant
ventilators, notably the Infant Star, could be lessened by reducing flow during the
expiratory phase. However, the resistance to expiration from any ventilator
valving system is negligible compared to the resistance of ET tubes used in the
neonatal population. This has been pointed out by a number of researchers over
the years, from Kelvin McDonald (now Dr. McDonald) to, more recently, Mike
Becker and colleagues fro the U of Michigan in Respiratory Care 2002:47 (9)994-97.
I think a better use of ViVe is to ensure sufficient gas flow for spontaneous
breathing in between ventilator cycles, as in IMV or SIMV, and yet set a
lower flow for inspiration that reduces turbulence. For example a Vi of 4 LPM and
a Ve of 10 LPM for a large, active infant. Of course, many clinicians, myself
included, clearly see the benefit of total assisted modes, such as A/C+ VG or
PSV+VG, in which it doesn't matter, since there is no time that the baby is
purely breathing spontaneously without support. I never use ViVe anymore, except
for noninvasive ventilation.
Hope this helps,
Draeger Ventilation Product Specialist
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