I am looking for information on how other hospitals are using IPV with APRV. Has there been any problems and how do you alter your ventilator during the treatment?
When do you decide to use the VDR-4?
Thank you!This message has been edited. Last edited by: maria,
we haven't found that APRV works well in conjunction with IPV. If we need IPV for secretion removal we will change the patient to PC and then place the IPV inline. Or if patient will tolerate it, IPV directly to the ETT.
As far as when to go to VDR, we use VDR as our first line for burn patients or patients with secretion management issues. We have found that some patients will respond to APRV others to VDR and visa versa in the ARDS patient population.
We do not have any VDR-4's(yet) but we do use a lot of APRV with and without IPV inline.
APRV works well at recruiting and keeping the lung open most of the time without needing IPV. We have seen that just allowing the patient to spontaneous breathe, it allows them to cough and clear/mobilize most secretions on their own.
When we have placed IPV inline with APRV, we really have seen much of a change/difference between the two. We also use a lot of kinetic therapy (roto-rest/roto-prone beds) along with APRV, so the need for mobilizing secretions is minimal including our burn pts.
I agree with Light on the ARDS pts because we have been using APRV with IPV inline trying to reverse the refractory hypoxemia. This is where I would like to hear if anyone's having good outcomes using the VDR-4 with these pts.
VDR can work in any patient population it is just a matter of adjustments. However, as I said before each patient seems to respond to different lung protective strategies.
We have taken patient with P/F rations below 100 to >250 in one hour with the transition to VDR from conventional ventilation. More and more hospitals are begining to try the VDR and see the strengths of this machine. The military hospital in Texas (San Antonio) is a great place to start when looking for data. LeHigh valley in PA, is another great source or St. Johns in Springfield, MO can help too. All have experience with the VDR and people that know how to use it.
Dr. Bird is not going to pay a lot of money for someone to research his product and tell him it works, he already knows. So evidence will be slim. The evidence is via word of mouth and practice.
Thanks for the information.
We having been using APRV for years, but are just starting to try IPV for the spinal cord patients with secretion issues.
I am a bit in the dark as I have never heard of either of these products. I did go to the VDR-4 website and find this pretty interesting.
I am interested to know how you set up your APRV for recruitment purposes. I have often heard this described as a poor mans osscillator but coupled with a VDR 4 I can see this as perhaps a more useful means of controlling CO2 in absence of a true osscillator. How does the VDR4 perform in various situations ie. spontanteous breathing, high plateau pressures, high resistance.
I find it interesting your distinction that the VDR4 improves oxygenation as it seems to be a purely ventilatory adjunct and the APRV more aptly increases MAP with the high and low PEEP. I have had some success with APRV in this realm and am eager to use it more as we go along. Why would VDR4 improve oxygenation?
When using APRV are all your patients spontaneously breathing, paralized or well sedated. My current interest lies in particularly difficult to ventilate H1N1 cases with remarkable FARDS.
Thanks for your thoughts
Using the APRV or BiLevel mode as a "poor mans oscillator" is a bit of a take off from using APRV as defined by Dr. Habashi.
Check out the article in Dec. 2008 Resp Care Journal
Mid-Frequency Ventilation: Unconventional Use of
Conventional Mechanical Ventilation as a Lung-Protection Strategy
Basically one uses RR's way over the 35 max of ARDSnet.
There are also some descriptions of using PC in "The Open Lung Concept".
Basically use a rate of 50 to more. In APRV or BiLevel mode Pressure Low is zero, Pressure High is 40 to even more. Ti of 0.6 and Te of 0.4 for instance. The lungs never "see" the PIP and the auto peep generated is the "set" peep. Imagine two representative alveoli--one the most normal/compliant and the other the lease compliant one that can still be opened up by the resultant mean airway pressure. If the mean pressure is 24 and a RR of 60 with 45/0 being the pressures and Ti of only 0.6......the most compliant regions won't be over-extended, the least compliant ones will be just held open, distension held to a minimum. But you have to remove as much deadspace as possible---no HME's and use active humidification, get rid of the flex tubing with the inline suction. Non-compliant tubing would be nice also (why waste the pressure on the tubing?). Rise time on Drager should be 0 seconds, on 840 the per cent may have to be less than 100 (or does the chattering confere benefit ala a percussive effect?).
And yes the VDR could function this way. I've not used the VDR clinically but at a conference workshop went over how to set it up. It's like setting up large rolling waves of PC ventilation and then having percussive ventilation on top. Then you can add a bit of a pressure spike time at end insp. I believe the percussions during the insp time can be set different than for the exp time. I imagine it could also be setup a bit in classic APRV fashion....extend insp time a bit more, keep the short drops and no set peep, just percussions atop a bit lower P High.
I don't think the advantages of the VDR over APRV would be to improve oxygenation. The touted advantage of the added percussive effect is in mobilizing secretions.
I think these approaches can be used for FLAARDS patients. But I worry than a bit of early success may only delay transfer to a center with Nitric Oxide, ECMO, Oscillator capability. (nebulized Flolan could be used instead of NO but many places may not be setup for that and doing so on the fly has it's disadvantages---been there and done that!).
PS.. an RT friend recently emailed me and asked about the differences between BiLevel (840 mode) and APRV (Drager mode and a strategy description).
I then emailed him back with this....
Once again we have a mix of marketing, strict "modes" by definition, and strategies all mixed together.
I think the vent manufacturer's either can't (or don’t want to)call the same thing the same thing.
Servo I vent also has a mode called "Bivent" or something.
From the standpoint of "what the ventilator actually does" they are pretty much the same thing.
Some differences I'm aware of, though not all the details.
On the Drager Vent you can't set any PS to be activated during the P High or P Low time periods. Unless of course you turn on ATC, but then only for the ET tube resistance. (of course for a patient with a # 9 ET tube you could dial in a #6 ET tube just as telling a camera a different film speed than what's in it in years past).
On the BiVent mode you can set up independent PS.
The 840 has a weird way to do it...you can set up PS for anything you want on the P Low Time. The default for the P High is (I think) 1.5 cwp. UNLESS the PS set during P Low exceeds the spread between the P High and P Low. For instance P High is 25 and P Low is 5 (stupid settings I know but for illustration). PS set on P Low is 5......P High PS is 1.5. But if you set P Low to be 15 and the PS to be 25 then the P High PS will be it'll jump over the P High by 10. I may not have the exact details right but pretty close.
Below my signature I've attached an old email where I enlist historical figures (and a modern day singer) to help with this...as regards understanding PS in BiLevel modes on the 840.
Also the 840's transition has some window where it looks to synch with the patient as it moves from P Low to P High.
Dr. Habashi (Drager's APRV guru Doc) characterized the addition of PS to these "APRV" modes as "contamination" of APRV. He feels adjustments of the drops (ventilation rate) is the way to address any ventialtory needs in addition to the spontaneous breaths.
So that is what the mode itself does...
Now onto strategies. I consider all the modes to able to be tweaked in order to do one of three basic strategies..
2) BiLevel Ventilation
3) Mid Frequency Ventilation
It's kind of funny though. All ventilation has to do some "airway pressure release" otherwise the patient would stay fixed at end inspiration. All ventilation has to be at least "Bilevel" (VDR is tri or quarto level).
But how I define the strategies.
APRV. I like to stick with the definition done by Dr. Habashi. The P Low is always set to Zero for maximum ventilatory gradient on the drop. The P High is set long enough for the patient to breath spontaneously. To titrate the drop time one looks at the expiratory flow and shortens Time Low such that it ends at about 1/4 to 1/3 of the max exp flow decay. You look at the patient breathing spontaneously. If too much inspiratory work increase P High to recruit FRC. If too much expiratory work decrease it.
So one can use the APRV STRATEGY with almost any mode. Since the new ventilators have the "free exhalation valve" (patient can breath spontaneously during insp time while in PC mode--be it PC proper, or volume mode which is really PC because Autoflow is on..or VC+ in 840). But good luck using PC and setting "Peep" and exp time to both zero and a fraction of a second!. The moniker of "APRV" is like a smoke grenade allowing you to apply "settings" unthinkable if another mode used. Hell you could setup CMV/Autoflow with longer Ti's, very short exp times, and call it "Volume Adjusted APRV" (VAAPRV....fun to say).
But the APRV strategy is easier to setup using APRV mode. You look at the exp flow and tweak Time Low.
BiLevel "strategy" is just that you do these longer P Highs that the patient can breath spontaneously on, longer T Low's also. Kind of rolling gentle recruitment. Someone else may be touting BiLevel as a specific strategy. But in any of the newer PC/VC hybrids which also have free exhalation valves (Servo I but not 300A) like Autoflow and VC+...you can set a long insp time and the patient can spontaneously breath atop it. Let's say you have a post op heart come back and you want to recruit them, they have enough preload to tolerate increased airway pressure. But RN's/MD's only want a Peep of 5. So let's say the RR is 10 and I set up Ti of 3 seconds and then 3 seconds exhalation. If then I walk away and later the patient wakes up they can breath atop that 3 seconds, just as if another Peep level. In older volume modes (or PC without free exhalation valve)the patient would then push against until PIP reached, then everything dumped!
Mid Frequency Ventilation is going over RR's 35 ala ARDSNET. Old Servo Open Lung Concept (Servo affiliated docs seem to have pioneered it---using rats and RR's up to 150 in PC mode and 1:1 I:E ratios). File attached (in email JW) showing it used with PC and RR 40 for post op hearts....look at the oxygenation post op!
So the RR is from 40 up to 100. Indeed on the Drager in APRV mode you can set a T High of 0.1 seconds, T Low 0.1 seconds, Rise time ZERO, get a RR 300. It's like a poor man's oscillator. Indeed a many years back at (a local hospital--JW) we had a patient one night that had pH 6.9 on PC (right lung white out, left lung relatively clear). I set him up in APRV mode but Time High 0.6 seconds, Time Low 0.4 seconds (RR 60), P High 45 and P Low Zero. No part of the lungs saw the 45, nor the zero. The auto peep and mean pressures identical. Holding open what can be held at mean 24 and not overdistending. His pH came to normal just as they were bringing out the THAM. You have to remove all deadspace possible (HME's and go for heated, remove inline suction flex added deadspace, even if available non-compliant tubing). Mark Siobal and others have also mentioned this. .
Well enough for now heh?
As regards PS on PB 840...
One of the main educational sticking points seems to be how PS is "rationed out" between PeepHigh and PeepLow in Bi-Level Ventilation mode. I would imagine how various people from history might have explained it......
Einstein would have said.......
"Unlike the speed of light relative to both a stationary and a traveling object, the absolute pressure support level arises from the setting relative to P Low only. The absolute value of pressure support is forever limited by the sum of P Low and the pressure support setting. As seen from the vantage point of P High, pressure support will only surpass P High when the combined forces of P Low and Pressure Support overtake it."
Karl Marx would have said,
"The yearning and aspiration of pressure support to overtake and override the airway resistance is suppressed by the P High Level. Only by joining forces with P Low in a combined pressure great enough, can Pressure Support smash it's way through the limitations imposed by P High. And only by P Low being equal to P High will the inequity of pressure support between the two peep levels ever be rectified."
Sigmund Freud would have said,
"P High will be forever envious of the advantage that pressure support enjoys at the lower P Low level. Even with pressure support fixated at a level high enough to give meaningful airway resistance relief at P High, P Low will still have a higher pressure support level. The recruitment offered by a robust P High will, however, mean that less elastic work must be done for the returned tidal volume in any pressure support level and in any Peep level. If an ET tube is orally fixated......"
Then I thought what a sexist pig I am because I didn't include any females In the historical examples above. Then it all got worse as I imagined Madonna singing something like...."If you want your pressure to push way up into my P High/ it's got to be something that makes me say 'oh my'......
I shoulda left well enough alone.
I have to disagree with your above comment. The VDR creates a MAP (mean airway pressure) in a different manner than APRV or conventional ventilation, and I have seen it greatly improve the oxygenation of patient on APRV. Each mode or adaptation of a mode to assist in oxygenation is trying to more effectively generate MAP. HFOV, HFPV, APRV, PEEP, Recruitment manuever..... all help oxygenation by generating the appropiate MAP. However each generates it differently.
Your adaptation of APRV to generate mid frequency, to me, shows that you know how to manipulate a vent. However, I feel that we should stick with more traditional applications of APRV when this term is used. This would reduce the confusion of actual APRV application. Just my thoughts. I know you know the difference, but others have problems. If you want midfrequency, stick with a mode that has a rate. Thigh to Tlow isn't really a rate that most APRV users concern themselves with.
I have not clinically used the VDR. I remember a discussion where the VDR was compared to the Oscillator. The VDR was touted as being both able to oxygenate as good as the Oscillator, but with the added advantage of mobilizing secretions at the same time. The skeptic in me tends to think that, if the VDR improves oxygenation over APRV mode, that it's because the true mean airway pressure (and auto-peep) is higher. On the other hand (arguing with myself) it could be that having variable ventilation (I think the VDR can have 3 to 4 different ventilation "schemes" going at once--and then if someone tweaks them regularly just to add more variety) decreases atelectasis and even is beneficial in promoting biologic variability within the entire organism.
I agree that perhaps a different moniker should be used (Mid Frequency) BUT the APRV mode can actually allow a higher RR than PC. Last time I tried to push the limits with Evita 4 (not XL) I could dial in rate 300 and Ti and Te 0.1 each. Try that on PC or CMV and I recall it won't let you do it. I don't have one handy so can't test it now. When using APRV mode and tweaking Te with exp flow it has an approach advantage when using auto-peep and not set peep.
Need to separate strict modes and strategies. For instance people say "don't use APRV mode for an asthmatic". OK, but let's imagine that some strange situation existed whereby the only mode available on any ventilator was APRV (imagine recall of other modes or bizarre failure of other modes---humor me). You could use the APRV mode with a "ventilate an asthmatic" strategy. Just set long Te, etc. Not the APRV strategy as described by Dr. Habashi, but the mode itself could be tweaked to a different strategy.
I heard through the grapevine that Drager is a bit worried over people using APRV mode in a fashion akin to a "Poor Man's Oscillator"---that the FDA won't like it or something. (the "others" who might have a problem!).
I first suggested this and it's been batted around the SF area RT community a bit.