Vent - What Doctor Decided

Madalot · Post by **Madalot** » Mon Apr 05, 2010 9:47 am

-SWS wrote:Well, in summary: 1) trigger controls adjust when IPAP begins, and 2) Ti or "inspiratory time" adjusts when IPAP ends.

Madalot wrote:I think one of the things I'm dealing with is that I'm using a ventilator and because it's a ventilator, they are ADAMANT about me not playing with settings.
I agree that you need to work all adjustments through your clinicians. Good luck, Madalot!

Thank you for spelling this out so clearly. I have written it down so I can talk to my RT about it, in these terms, when she calls me.

-SWS · Post by **-SWS** » Mon Apr 05, 2010 10:05 am

Madalot wrote:
-SWS wrote:Well, in summary: 1) trigger controls adjust when IPAP begins, and 2) Ti or "inspiratory time" adjusts when IPAP ends.

Madalot wrote:I think one of the things I'm dealing with is that I'm using a ventilator and because it's a ventilator, they are ADAMANT about me not playing with settings.
I agree that you need to work all adjustments through your clinicians. Good luck, Madalot!
Thank you for spelling this out so clearly. I have written it down so I can talk to my RT about it, in these terms, when she calls me.

Okay. But bear in mind my simplification above was only for the purpose of comparing those two machine controls or parameters.

In reality, the beginning of IPAP can occur based on either a patient-flow based trigger or a time-based trigger. And the same holds true for the ending of IPAP as well: a patient-flow based trigger or a time-based trigger might be used by the machine.

The beginning of IPAP: employs patient inspiratory flow as the flow based and primary trigger, but BPM as the backup or time-based trigger (in S/T mode BPM is a time-out and hence backup).

The ending of IPAP: employs patient expiratory flow as the flow based and primary trigger, but Ti as the backup or time-based trigger (in S/T mode Ti is also a maximum limit or time-out)

Madalot · Post by **Madalot** » Mon Apr 05, 2010 10:37 am

-SWS wrote:
Madalot wrote:
-SWS wrote:Well, in summary: 1) trigger controls adjust when IPAP begins, and 2) Ti or "inspiratory time" adjusts when IPAP ends.

Madalot wrote:I think one of the things I'm dealing with is that I'm using a ventilator and because it's a ventilator, they are ADAMANT about me not playing with settings.
I agree that you need to work all adjustments through your clinicians. Good luck, Madalot!
Thank you for spelling this out so clearly. I have written it down so I can talk to my RT about it, in these terms, when she calls me.
Okay. But bear in mind my simplification above was only for the purpose of comparing those two machine controls or parameters.

In reality, the beginning of IPAP can occur based on either a patient-flow based trigger or a time-based trigger. And the same holds true for the ending of IPAP as well: a patient-flow based trigger or a time-based trigger might be used by the machine.

The beginning of IPAP: employs patient inspiratory flow as the flow based and primary trigger, but BPM as the backup or time-based trigger (in S/T mode BPM is a time-out and hence backup).

The ending of IPAP: employs patient expiratory flow as the flow based and primary trigger, but Ti as the backup or time-based trigger (in S/T mode Ti is also a maximum limit or time-out)

Got it. Will keep all of this in mind when I talk to my RT. Probably won't be until tomorrow -- it usually takes her at least 24 hours to call me back.

-SWS · Post by **-SWS** » Mon Apr 05, 2010 12:39 pm

I guess I ought to mention Respironics nomenclature once again, since Jeff clarified it very nicely earlier in this thread. The real-world terms "trigger" and "trigger event" are highly generic control-logic terms. And in those generic control-logic terms a "trigger event" (breath or time limit in this case) will "trigger" or commence the next machine response (an IPAP or EPAP transition in this case).

As Jeff pointed out, Respironics (perhaps respiratory medicine in general), chooses to call control-logic triggers associated with EPAP as "cycles" instead---another generic term. I was formally trained in control logic, and always generically termed them all "triggers". Hope that didn't confuse anybody.

The main thing is that while in S/T mode, inspiratory flow and BPM work on commencing IPAP (as primary flow-based and secondary time-based triggers respectively). And expiratory flow and Ti work on terminating IPAP (as primary flow-based and secondary time-based triggers respectively). Generically speaking, both time-based triggers are backups for the case of patient flow not showing up on time (while in S/T mode).

So when either time-based backup is set too "narrow" (either BPM or Ti settings), then the patient can sometimes feel "machine rushed". If EPAP is happening too soon then Ti might require lengthening; and If IPAP is happening too soon then BPM might need to be set lower (but it's already set low in Madalot's case).

jnk · Post by **jnk** » Mon Apr 05, 2010 1:15 pm

-SWS,

Do I read you correctly that, if it were you, you would probably want to try Auto-trak before messing with any of that other stuff, anyway? That would be your druthers for step one?

jeff

jnk · Post by **jnk** » Mon Apr 05, 2010 1:31 pm

A partial, edited Klingon dictionary:

Ventilator Mode Glossary of Terms

Autotrigger--an unintended initiation of breath delivery by the ventilator, e.g., by an external disturbance such as movement of the breathing tube or an inappropriate trigger sensitivity setting. (Sometimes mistakenly called autocycling.)

Cycle--verb; to end the inspiratory time (and begin expiratory flow); noun, a breath (inspiration and expiration).

Cycle variable--the variable (usually pressure, volume, flow, or time) that is used to end the inspiratory phase.

Machine cycled--refers to an inspiratory phase that is terminated by the ventilator independent of the patient’s ventilatory actions; usually by a preset inspiratory time or tidal volume.

Machine triggered--refers to an inspiratory phase that is initiated by the ventilator independent of the patient’s breathing motions; usually by a preset mandatory breath frequency but may include other criteria such as a minimum spontaneous breath frequency or minimum minute ventilation.

Patient cycled--refers to an inspiratory phase that may be terminated by the patient (i.e., through active breathing motions or passive lung mechanics) independent of the ventilator settings; usually by a preset peak inspiratory pressure or end expiratory flow threshold.

Patient triggered--refers to an inspiratory phase that is initiated by the patient (i.e., through active breathing motions or passive lung mechanics) independent of the ventilator settings; usually by a preset pressure or flow change relative to baseline.

Trigger--verb, to start inspiration.

Trigger variable--the variable (e.g., pressure, volume, flow, time, diaphragmatic EMG, chest impedance) that is used to start the inspiratory phase.

-- http://www.rcjournal.com/guidelines_for ... ossary.cfm

© The Journal RESPIRATORY CARE Company

Madalot · Post by **Madalot** » Mon Apr 05, 2010 1:36 pm

I think this is one of the reasons I get so overwhelmed with all of this sometimes -- there are too many options, with too many variables, all of which can be very confusing for the poor patient.

And I think part of the problem is that for some of the issues I'm experiencing, I can't tell you for sure what's happening -- whether the inhale is too soon, or exhale too soon or what. I just know that it doesn't "feel" right to me during that moment.

I still haven't heard from my RT yet.

-SWS · Post by **-SWS** » Mon Apr 05, 2010 1:50 pm

jnk wrote: Do I read you correctly that, if it were you, you would probably want to try Auto-trak before messing with any of that other stuff, anyway? That would be your druthers for step one?

That's probably what I'd try next based on what Madalot says, Jeff. Above I mentioned the generic concept of flow-based triggers as primary and time-based triggers as secondary or "backup". AutoTrak specifically allows the machine's algorithm to automatically maintain the thresholds and sensitivity settings of flow-based triggers.

But if I were Madalot I'd probably first attempt to pin down sequencing a little better as I describe to her below.

jnk wrote:A partial, edited Klingon dictionary:

Thanks for that glossary... It's not just Respironics, then. Rather the entire RT field uses the term "trigger" for the control-logic response at the beginning of inspiration and the term "cycle" for the control-logic response at the end of inspiration. That's decades of a control-logic paradigm for me to place aside when I'm discussing the IPAP-to-EPAP transition, then. I'm almost guaranteed to absent-mindedly continue terming them all as generic control-logic "triggers".

Madalot wrote: And I think part of the problem is that for some of the issues I'm experiencing, I can't tell you for sure what's happening -- whether the inhale is too soon, or exhale too soon or what. I just know that it doesn't "feel" right to me during that moment.

Well, once a patient gets really, REALLY out of sync with the machine, then IPAP and EPAP will both occur at the wrong time. The idea is to pay close attention to the few times when you can tell what INITIALLY started that entire out-of-sequence mess: IPAP coming too early or EPAP coming too early. If you can pin that pattern down, then candidate machine changes become a bit easier to figure out...

Madalot · Post by **Madalot** » Mon Apr 05, 2010 1:53 pm

-SWS wrote:
jnk wrote: Do I read you correctly that, if it were you, you would probably want to try Auto-trak before messing with any of that other stuff, anyway? That would be your druthers for step one?
That's probably what I'd try next based on what Madalot says, Jeff. Above I mentioned the generic concept of flow-based triggers as primary and time-based triggers as secondary or "backup". AutoTrak specifically allows the machine's algorithm to automatically maintain the thresholds and sensitivity settings of flow-based triggers.

But if I were Madalot I'd probably first attempt to pin down sequencing a little better as I describe to Madalot below.

jnk wrote:A partial, edited Klingon dictionary:
Thanks for that glossary... It's not just Respironics, then. Rather the entire RT field uses the term "trigger" for the control-logic response at the beginning of inspiration and the term "cycle" for the control-logic response at the end of inspiration. That's decades of a control-logic paradigm for me to place aside when I'm discussing the IPAP-to-EPAP transition, then. I'm almost guaranteed to absent-mindedly continue terming them all as generic control-logic "triggers".

Madalot wrote: And I think part of the problem is that for some of the issues I'm experiencing, I can't tell you for sure what's happening -- whether the inhale is too soon, or exhale too soon or what. I just know that it doesn't "feel" right to me during that moment.
Well, once a patient gets really, REALLY out of sync with the machine, then IPAP and EPAP will both occur at the wrong time. The idea is to pay close attention to the few times when you can tell what INITIALLY started the entire out-of-sequence mess: IPAP coming too early or EPAP coming too early. If you can pin that pattern down, then candidate machine changes become a bit easier to figure out...

The above statement makes sense. I'll try to focus and pay attention and see if I can determine what STARTED the problem. The problem that I have is that frequently when I notice it, I've been watching TV or almost asleep and really can't tell for certain what happened. But I'll try to pay closer attention when I'm watching TV.

Edited to Add: When I first increased the Inspiratory Time from 1 to 2, it seemed so much better. And I still think it's helping -- most of the time anyway.

-SWS · Post by **-SWS** » Mon Apr 05, 2010 2:31 pm

AutoTrak described for the technically curious:
http://autotrak.respironics.eu/technology.asp

Madalot · Post by **Madalot** » Mon Apr 05, 2010 2:54 pm

-SWS wrote:AutoTrak described for the technically curious:
http://autotrak.respironics.eu/technology.asp

I think by the time we get this ventilator set up for me, I'm going to be an expert on the subject!!! Not really, but I sure will know a lot more than the average bear!!!

DreamOn · Post by **DreamOn** » Mon Apr 05, 2010 2:58 pm

Madalot wrote:I think by the time we get this ventilator set up for me, I'm going to be an expert on the subject!!! Not really, but I sure will know a lot more than the average bear!!!

That's for sure! Hang in there....

Madalot · Post by **Madalot** » Mon Apr 05, 2010 4:10 pm

DreamOn wrote:
Madalot wrote:I think by the time we get this ventilator set up for me, I'm going to be an expert on the subject!!! Not really, but I sure will know a lot more than the average bear!!!
That's for sure! Hang in there....

Well, out of sure need, I have already learned more than the average person that has sleep apnea and needs a cpap or bipap! My family member is a classic example. This person has absolutely no idea other than he snored, did a sleep study and got a machine in the mail! Even some of the basic questions I asked were totally unknown.

And it's because of this site and the people here that I am involved in my treatment and can ask some pretty intelligent questions (at times) to help them figure out what to do.

And I'm hanging in as best I can.

Oh -- I got my van fixed today! A 180-mile round trip to the dealership resulted in a 5-minute fix. Go figure. But it's fixed and I'm a happier camper today because of it.

Banned · Post by **Banned** » Mon Apr 05, 2010 5:05 pm

Hey gyrl,

To summarize all the good stuff on this message board,
ask your doctor for the following changes:

Trigger Type: Auto-Trak
Inspiration Time: 1.9 sec
Rise Time: 4

-SWS wrote:The longer recommended rise times for restrictive disease typically have to do with comfort-related pressure slope adjustments relative to those wider PS values---not lessening muscle work load.

Since you have a very wide PS value, I would lean toward comfort-related pressure slope adjustments (longer Rise Time and more natural breathing). And screw the WOB (Work-of-Breathing) since the vent will be doing the work anyway.

In any event,
decreasing Inspiration Time
and increasing Rise Time
should help with the Minute Ventilation.

-SWS · Post by **-SWS** » Mon Apr 05, 2010 5:36 pm

Banned wrote:And screw the WOB (Work-of-Breathing) since the vent will be doing the work anyway.

There's absolutely no reason to increase rise time UNLESS Madalot's rt=3 is uncomfortable to sleep. And with a wide enough PS, that rt@3 just might be uncomfortable for Madalot. Absolutely nothing wrong with trying rt=4 for the sake of comparison against rt=3 IMO. However...

Banned wrote: and increasing Rise Time should help with the Minute Ventilation.

Increasing rise time makes for a more gradual pressure-assist slope during inspiration---which in turn marginally diminishes minute ventilation at any given breath rate.

Banned wrote:Inspiration Time: 1.9 sec

Did I miss the post in this thread where that change was substantiated in any way?

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