Critical thinking: Vent Management

RRTMedic

RRTMedic

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Let's say you just intubated a 4 month old child. You are preparing to place this patient on a ventilator that allows you to select patient size, such as infant, pediatric, or adult.

You elect to place the patient in volume control per IBW under the INFANT size category. You notice that she has very quick inspiratory times that seem distressing. Inspiratory time of say, 0.3 secs. You agree this is too low for this patient, but your vent won't allow you to increase the Insp time due to you being in the Infant size category.

So you switch sizes and go to the PEDIATRIC size. Fortunately it the pediatric size allows you to increase your insp time to a comfortable 0.6-0.8 range and you adjust your rate to a 1:2 I:E interval. However, this PEDIATRIC size won't allow you to drop your tidal volume below 100 ml.

How do you ventilate this child at this point without changing sizes again and settling for the unnaturally low inspiratory time?
 
Again, yet another reason I feel the "AMD" thread should be tied to the HEMS section, but I digress...

@RRTMedic I will be the first to admit I am severely lacking with pediatric vent management, specifically, infant vent management, but this is what first comes to mind...
http://www.pediatrics.emory.edu/ccm/lectures/files/HFOV.ppt

Also, my understanding is the smaller pediatrics such as these are the rare population that may benefit from full paralysis and CMV so long as your ventilator management in this age group isn't lacking. By all means, feel free to elaborate, though.
 
Im guessing the answer here is a MacGuyver set up, since you can't adjust the tidal, perhaps you'd have to make up for it by adding additional dead space tubing to the circuit?
 
DEmedic said:
Im guessing the answer here is a MacGuyver set up, since you can't adjust the tidal, perhaps you'd have to make up for it by adding additional dead space tubing to the circuit?
Click to expand...

That's an interesting thought that I admit, I have never thought to do!! Risky, but definitely feasible!

Let's say this ventilator has a variety of different modes... there is a way :)
 
Remi said:
Does the PCV mode offer more control over i time on the LTV?
Click to expand...

You definitely are moving in the right direction!

So the answer to this would be to accept the fact that you have to stay in the PEDIATRIC size for the sake of the inspiratory time. Then switch to pressure control because guess what---it's just pressure. The tidal volume will be what it will be, no matter what size you're in.

Any ideas of PCV settings?
 
RRTMedic said:
You definitely are moving in the right direction!

So the answer to this would be to accept the fact that you have to stay in the PEDIATRIC size for the sake of the inspiratory time. Then switch to pressure control because guess what---it's just pressure. The tidal volume will be what it will be, no matter what size you're in.

Any ideas of PCV settings?
Click to expand...
What would be the caveat to ASV, and allowing the vent to adjust to the patients compliance?
http://www.rtmagazine.com/2007/02/pressure-controlled-ventilation/
Under the "initial settings" of this article it references subtracting the patients PEEP from the MAP, would this be similar to "driving pressures"?
 
RRTMedic said:
You definitely are moving in the right direction!

So the answer to this would be to accept the fact that you have to stay in the PEDIATRIC size for the sake of the inspiratory time. Then switch to pressure control because guess what---it's just pressure. The tidal volume will be what it will be, no matter what size you're in.

Any ideas of PCV settings?
Click to expand...

Depends why we tubed in the first place?
 
VentMonkey said:
What would be the caveat to ASV, and allowing the vent to adjust to the patients compliance?
http://www.rtmagazine.com/2007/02/pressure-controlled-ventilation/
Under the "initial settings" of this article it references subtracting the patients PEEP from the MAP, would this be similar to "driving pressures"?
Click to expand...

Good thinking on this... unfortunately this mode isn't available on this vent (LTV) and I'm not sure if it's role in pediatrics. To be honest, I've never worked with ASV.

Typically, "driving pressures" refers to pressure control setting or the inspiratory work.
 
RRTMedic said:
Good thinking on this... unfortunately this mode isn't available on this vent (LTV) and I'm not sure if it's role in pediatrics. To be honest, I've never worked with ASV.

Typically, "driving pressures" refers to pressure control setting or the inspiratory work.
Click to expand...
Cool, thanks. I just listened to a podcast the other day on this, which apparently is still quite controversial even in the ICU settings.

Though it does sound like driving pressures is something gaining momentum with ARDS patients in the ICU.

http://www.nejm.org/doi/full/10.1056/NEJMsa1410639
 
Do we work together? We just had an email about this.

With the Revel ventilator in Infant Pressure Ventilation it maxes out the I time at 0.3 but if you select the tidal volume (which will be greyed out) and increase it to 150 you can then go back adjust the I time up to 0.6-0.8 while staying in pressure control.

Similar to adjusting I:E sometimes; it will max out based on the I:Ecalc and respiratory rate so you will have to adjust your rate down in order to go up on your I:E and then you can go back up on your rate.
 
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Chase said:
Do we work together? We just had an email about this.

With the Revel ventilator in Infant Pressure Ventilation it maxes out the I time at 0.3 but if you select the tidal volume (which will be greyed out) and increase it to 150 you can then go back adjust the I time up to 0.6-0.8 while staying in pressure control.
Click to expand...

Haha unless you hang around Charlotte, NC I don't think we've met. Unfortunately I had to figure this all out in a trauma room as the sole RT
 
RRTMedic said:
Haha unless you hang around Charlotte, NC I don't think we've met. Unfortunately I had to figure this all out in a trauma room as the sole RT
Click to expand...

We had a very similar situation recently. I never would have thought to do that.
 
VentMonkey said:
Cool, thanks. I just listened to a podcast the other day on this, which apparently is still quite controversial even in the ICU settings.

Though it does sound like driving pressures is something gaining momentum with ARDS patients in the ICU.

http://www.nejm.org/doi/full/10.1056/NEJMsa1410639
Click to expand...

Yep driving pressures are very important because they are responsible for the opening and closing of the alveoli---essentially they are to blame for atelectrauma that leads to acute lung injury. Very much the reason why I advocate for much higher PEEPs in adult patients. I'm not so sure the literature is there for pediatrics; I'll have to do more research. But driving pressures are basically your plateau minus Peep... the degree of opening and shutting of those alveoli.
 
So guys as far as initial settings go for PCV in this four month old...

Pressure Control: 10-15 cmH2O
PEEP: 5 cmH2O
Rate: 25-35/min
Insp Time: 0.5-0.8 secs
Sensitivity: 2 Lpm
I:E (adjust rate and IT to 1:2)
FIO2: 60% and weaned quickly to room air
Target volumes 35-70 ml
Target Minute Ventilation: aim for at least 0.6 LPM and then re-evaluate CO2.

I'd recommend keeping PIP < 25 cmH2O. Babies typically breath over a lot so their rates will vary. You may need to titrate your settings according to minute volume instead of breath by breath tidal volume.

Ideal venous blood gas? pH 7.25-7.35 and PvCO2 50-55. Remember, no hyperventilating unless signs of herniation (and honestly, not sure if hyperventilating is a thing with babies mostly because they don't have completely closed fontanelles so herniating usually is not an issue).

Any other suggestions or thoughts?
 
The initial settings I was going to type were almost identical to yours. I was going to say PCV 15/5, 1:2, 20-25/min.

I think you are right about hyperventilating.....the open fontanelles make both uncal and transtentorial herniation less of an issue.
 
Our vent doesn't offer patient sizes (impact AEV). a simple answer would be to leave this on adult mode and use A/C pressure control. obviously use pediatric tubing, Maybe cut some off to eliminate more dead space. i am not a pedi transport specialist, but to my understanding they typically are routinely paralyzed for any ventilator operations. adjust the rise time up between 8-10 and the I:E to 1:2. adjust peep in an effort to reduce driving pressure, Driving pressure= Pplat-PEEP, RR 25-30. dont forget that OG tube !!!

@RRTMedic how did i do?
 
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