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truetiger
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This is the hospital's doing prior to our arrival. Our patient's are properly sedated/paralyzed upon our arrival.
What vent mode is best?
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PRVC? Not even close. That is a special mode on ventilators which determines compliance and adjusts pressures to deliver a VT.
PC (Pressure Control) is a very common mode. You will find it on just about every transport ventilator. If anyone here is using the LTV, notice it gives a choice of Volume or Pressure on one button and Assist Control or SIMV on another button. Assist Control and SIMV both pertain to Volume and Pressure modes. If you are doing any type of CCT you really should have someone show you this on your ventilator and explain it.
Didn't you read what you posted for quotes from HESS and did you bother to read his full chapter.
I doubt if you want any of the ICU RRTs who have read this to respond since most of them have read Hess and McIntyre.
BTW, the author (Hess) of that definitions you referenced is an RRT (Respiratory Therapist). The explanations I am giving are straight from his material.
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Do you use the hospital's settings or just put them on SIMV because that is what you like regardless of patient needs.
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truetiger
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They were sedated and paralyzed, per our medical director, then put on our AutoVent. It's an uphill battle getting the admin to buck up for a nice transport vent.
The way you've been describing A/C is like SIMV with a set tidal volume.
That's because in modern ventilators it pretty much is, and the only reason to choose one over the other is user comfort with settings.
Not even close unless the patients are paralyzed with 0 spontaneous breathing.
Please read and LOOK at the graphics in the chapter linked to.
Does anyone here use a graphic monitor on their transport ventilator. If you did the difference should be very obvious if you had even seen both modes used.
At some point you must think about the patient and all the many different diease processes. You might need to get out of your comfort zone and learn what all the other settings are on the ventilator. It also sounds like sensitivity, I-time, rise, termination or any of the other settings are considered when setting up a ventilator even in SIMV. To use only a volume mode is also very short sighted since there are several reasons for using PCV in either AC or SIMV. PCV is not PRVC in most standard transport ventilators or even ICU vents.
To use only one mode is like saying you can only intubate with a Mac blade.
AC is a set tidal volume or a set pressure if you are using PCV (PAC).
AC modes are in synch with the patient on all modern ventilators. SIMV is a term which has stuck since the 1970s long before modern ventilators. But, depending on which Autovent you are using, I would say that is more like an old IMV machine with very little synch. Which ATV are you using and we will discuss it? Are these ICU patients you are transporting IFT by AutoVent?
The only difference between SIMV and A/C on the vents I work with is in SIMV not every breath is assisted (volume wise), where as A/C they are.
In this situation it matters very little for meaningful outcomes which you choose.
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What type of patients are you transporting? Ventilator settings make a big differences, as does the type of ventilator, for critically ill patients.
As far the Autovent which was mentioned earlier by another, this vent probably should have very limited uses like getting a nearly dead patient to the hospital and freeing up the Paramedics' hands. Reading about it is kinda scary if its use is attempted on CCT with an ICU patient. Yes this patient would have to be on a paralytic which also brings up issues about plugged or dislodged ETTs in transports.
Autovent
http://www.emergency-safe.com/inservices/IST 2011/February/Module 5 Autovent 3000 set up and use.pdf
Not transporting them anywhere. And beyond lung protective strategies for lung injury processes and increased expiratory times for obstructive processes I'm afraid that the details just don't matter much in terms of getting your patient off the blower as quickly as possible.
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Off the blower?
Is this how you view ventilators?
Are you saying all of this based only on an inservice on ventilators given to you by a sales rep to sell your agency on their ventilator?
Since you brought up lung protective strategies what ventilators are you using? What about restrictive processes or acute diseases which can present with ARDS? Have you ever been in an LTACH?
Puritan Bennett 840. Not sure what you're getting at with your second question? Are you asking what I would do in that case? I would drop my TV (though honestly everyone should probably be at that 6-8cc/kg regardless of process) and increase my expiratory times (and yes this is simplified).
And yes. This is how I view ventilators. A tool. One that should be used as infrequently and for as short as time as humanly possible. So, yes, the moment a patient goes on the vent my very next thought is how do I get them off this damn thing as quickly and safely as possible.
Am I concerned about patient comfort? Of course, and I can make all kinds of great adjustments to try and improve patient comfort, though lets be honest if it were me or mine, I would just rather have some appropriate sedation/analgesia. But that isn't what this is about. This was about overall decision of using SIMV vs. A/C. And where I am, with these vents, there is no difference.
ExpatMedic0
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Well since you like to ask questions, I have one for you. Just who are you giving advise to other health care providers regarding ventilators on an EMS forum? Whats your background, healthcare provider level, and education? Why do you omit that information on your profile? No offense to you, but I would like to know exactly who I am getting information from here. I know some pretty crafty boy scouts with a first-aid merit badge who can site wikipedia and RRT manuals.
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KellyBracket
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I love it - an impassioned discussion over ventilation! I'll share my amateur perspectives.
When I rotated through the medical ICU (at a tertiary/quaternary-level hospital), AC was used 98% of the time. This was the mode used in ARDSnet, it was explained to me, and so was the only evidence-based mode.
When I was in the surgical ICU, they proselytized about APRV, and its effectiveness in treating ARDS. They had to cancel a study looking at prone-positioning, in fact, since APRV ventilation cured all their patients before they could be enrolled. AC was for hayseeds, the "Devil's mode."
Of course, in the pediatric ICU, all the kiddies were on PRVC because "they aren't little adults..." Or some reason, I forget.
So, after getting a well-rounded exposure to ventilation modes, I frankly have to agree with Dwindlin; ventilators are "blowers," tools to buy some time while we figure out the primary disease process. Any talk of the "best" mode is mis-framed from the onset. It's probably better to choose the "less-bad" mode!
When I rotated through the medical ICU (at a tertiary/quaternary-level hospital), AC was used 98% of the time. This was the mode used in ARDSnet, it was explained to me, and so was the only evidence-based mode.
When I was in the surgical ICU, they proselytized about APRV, and its effectiveness in treating ARDS. They had to cancel a study looking at prone-positioning, in fact, since APRV ventilation cured all their patients before they could be enrolled. AC was for hayseeds, the "Devil's mode."
Of course, in the pediatric ICU, all the kiddies were on PRVC because "they aren't little adults..." Or some reason, I forget.
So, after getting a well-rounded exposure to ventilation modes, I frankly have to agree with Dwindlin; ventilators are "blowers," tools to buy some time while we figure out the primary disease process. Any talk of the "best" mode is mis-framed from the onset. It's probably better to choose the "less-bad" mode!
I just got done spending several months in the SICU here at my school (anesthesia bound so very little time in the MICU in comparison). I think APRV has lost its wind (pun most definitely intended) some, we only used in very bad cases when everything else failed to oxygenate the patient. For the most part 99% of the patients were either A/C or SIMV, which ever that weeks attending was most comfortable with.
KellyBracket
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APRV probably fits a surgical/trauma population better - i.e. fewer co-morbid air-trapping conditions.
I've never seen anyone on SIMV!
I've never seen anyone on SIMV!
Agree on the patient population. As for the SIMV, as I've said in the discussion thus far, at least with our vents the only difference is the number of volume assisted breaths. In A/C all of them will be, in SIMV only the "IMV" breaths.
From what I've seen thus far the literature is a wash. Some argue that SIMV is better since it "strengthens" the diaphragm, but again, I don't think what literature is out there bears this out.
Years of working in critical care and doing critical care transports with various ventilators.
I wouldn't exactly compare books written by Hess and McIntyre "boy scout" manuals. That is just insulting to these professionals.
I don't know any of your background either but sometimes by the posts you can tell if they are just BS or might actually have some idea what they are talking about. But then you might not have enough background to understand which then might lead to your own confusion.
I am on this forum because this does interest me. I have to trust you know what you are doing when you assume care for my patients which need to be transported from the ICU. I also take report from EMTs and Paramedics who bring patients. Why do you assume what you do does not affect anyone else? If nothing else I would like some to just find more education about ventilators and critical care. To think you know it all and no one else does it ignorant and arrogant. It also seem you want to believe EMTs and Paramedics are the only ones in health care who know anything or that the opinions and education of an RN who may have spent years in a critical care unit either stationary or mobile is useless.
What ventilators are you using? What is the triggering mechanism? Demand or continuous flow?
APRV is very popular. Did you know it delivers two levels of pressure at extended time periods while allowing someone to breathe spontaneously at both levels? For someone who believes in pressure support this should be a dream come true for you.
When you read the literature you should take note on what the patient disease process it.
Also, as I mentioned before and the textbooks quoted have and any other site explaining SIMV will, the difference will also be in the flow delivery. You also must understand that the PSV breaths associated with the SIMV mode will be compliance dependent. They will also vary with just a tiny bit of secretions. This can make a big difference in the VT delivered and might be inadequate to maintain a decent minute volume. The patient will also have to work harder to get the VT for the MV they want.
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APRV is a spontaneous mode. It can be used only if the patients can initiate all their breaths. AC does not have that requirements. APRV (BiLEVEL on some vents) definitely has its purpose when sedation is lightened and they can maintain adequate volumes with the PSV breaths at both pressure levels to stay with an ARDS protocols.
APRV is not PRVC. Kids should not be ventilated with high pressures but some may need a more consistent VT which might have a large variance due to compliance.
Do you know how many different ventilators and modes there are for all the different diseases? Believe it or now but just one mode doesn't always work for everyone.
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