Revel alarm question/with scenario.

GMCmedic

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Here is a brief-ish rundown of the scenario. 13 y/o Female patient 89kg with an IBW of 60kg. Post elf inflicted hanging, worked in the field and ROSC obtained. Intubated with a 7.0, 22cm at the lips.

Sending MD reports pupils fixed at 7, with no movement and no spontaneous respirations, patient has no sedation or paralytic on board. Initial assessment confirms this.

Sending facility vent settings used which were AC volume, respirations 28, TV 350, PEEP 8, FiO2 65%. Sats 98-99, ETCO2 low 30s.

As patient was being moved to the AC, we started getting "Patient circuit" alarms. We never got a high pressure alarm. Checked all connections multiple times with no relief in alarms. Changed the vent tubing to another set with no improvement. Eventually we started getting VTE anywhere from 340-1000.

It appeared in the aircraft that the patient was coughing. Sedated with Fentanyl 3 times during ~30 minutes flight and a ketamine drip was started about halfway through at 2mg/kg/hr. Again, no improvement.

While moving patient to the ICU at receiving I noticed what I initially thought was coughing, appeared to actually be irregular spontaneous (neuro) breathing. It was difficult to notice with aircraft vibration earlier.


My question is why did it cause a patient circuit alarm?

The flight is fresh on my mind so if you think anything else might be relevant, feel free to ask.
 

NomadicMedic

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I don’t have an answer for your question, but that sounds like an awful situation. I’m sorry you had that one.
 

Carlos Danger

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I'm not familiar with the Revel vent but it sounds like a flow sensor issue.

How much fentanyl did you give in total?
 

E tank

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Don't know what your training or experience is so forgive me if I'm appearing pedantic. I don't mean to be. That said, when odd stuff is going on with mechanical ventilation, best thing to do is take the patient off of the vent and hand ventilate. No substitute for getting a real feel for the bag, compliance of the chest and respiratory effort. Lot's of questions can be answered just doing that.

I'm not familiar with the generic "patient circuit" alarm. Is that just a catch all for the ventilator can't tell you why it's alarming? Varying tidal volumes might give you varying end tidal CO2 that may fall out of the set alarm parameters and trip an alarm. Same goes with minute volume alarms.

Could you just have paralyzed her?
 

Aprz

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I have the manual on my phone. Here is a screen shot of the pages covering patient circuit fault. screenshot on imgur

From what I am reading, it doesn't seem to be a problem with the patient's vent settings or the patient herself. Seems like a circuit/equipment issue like the vent alarm said.

Since you switched out the circuit, I think it was unlikely a problem with the circuit itself unless maybe storage problem with the circuits, if all stored the same way? Maybe the sensors were occluded? Did you do a vent check > circuit check after to see if the problem was reproducible without being connected to a patient?

As far as I know, Revel doesn't monitor CO2. Doesn't have alarm for CO2. They would've been monitoring CO2 separately on their monitor. It has low/high pressure alarm, low FiO2, low VE, and I guess low SpO2 and pulse rate (haven't used the last two, been using a separate monitor instead).
 
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GMCmedic

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I'm not familiar with the generic "patient circuit" alarm. Is that just a catch all for the ventilator can't tell you why it's alarming? Varying tidal volumes might give you varying end tidal CO2 that may fall out of the set alarm parameters and trip an alarm. Same goes with minute volume alarms.
Most commonly you get the circuit alarm when the vent circuit had come disconnected from the ETT. @Aprz posted a screenshot of the relevant alarm page but I condensed it here to what "should" cause that alarm.

We do not monitor ETCO2, Spo2, or heart rate on the ventilator. All of that is monitored with our Zoll.

Could you just have paralyzed her?

We typically avoid that unless it's necessary for adeqaute ventilation/oxygenation. In this case the alarms were just a confusing annoyance.
 
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GMCmedic

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I have the manual on my phone. Here is a screen shot of the pages covering patient circuit fault. screenshot on imgur

From what I am reading, it doesn't seem to be a problem with the patient's vent settings or the patient herself. Seems like a circuit/equipment issue like the vent alarm said.

Since you switched out the circuit, I think it was unlikely a problem with the circuit itself unless maybe storage problem with the circuits, if all stored the same way? Maybe the sensors were occluded? Did you do a vent check > circuit check after to see if the problem was reproducible without being connected to a patient?

As far as I know, Revel doesn't monitor CO2. Doesn't have alarm for CO2. They would've been monitoring CO2 separately on their monitor. It has low/high pressure alarm, low FiO2, low VE, and I guess low SpO2 and pulse rate (haven't used the last two, been using a separate monitor instead).

We do a circuit test every morning and the initial circuit passed. We did not do one on the secondary tubing, and I didn't think to do another test after the patient was switched to the hospital vent.

There were no other alarms to indicate a leak.

And we do not use any of the monitoring features on the revel, all of that is done externally on our cardiac monitor.
 
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GMCmedic

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I spoke to a few people within the organization and have gotten a plausible answer.

Apparently this is a rare case where the patient was taking in so much volume in such a short time with the neurogenic breathing, that the ventilator software interpreted it as a disconnected circuit.

It was also explained that this is a rare case where paralyzing the patient is encourage.
 

silver

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I spoke to a few people within the organization and have gotten a plausible answer.

Apparently this is a rare case where the patient was taking in so much volume in such a short time with the neurogenic breathing, that the ventilator software interpreted it as a disconnected circuit.

It was also explained that this is a rare case where paralyzing the patient is encourage.
Is there a negative pressure alarm on the vent?
 

Carlos Danger

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I spoke to a few people within the organization and have gotten a plausible answer.

Apparently this is a rare case where the patient was taking in so much volume in such a short time with the neurogenic breathing, that the ventilator software interpreted it as a disconnected circuit.

It was also explained that this is a rare case where paralyzing the patient is encourage.
That was along the lines of what I was thinking. I have never seen a transport vent with a negative pressure alarm, (again, I am not familiar with the particular vent at all), but of course they all have flow sensors and any high demand or unusual flow pattern will typically trigger an alarm. I think it is one of the reasons why transport vents in general tend to be more finicky and alarm more easily than ICU vents.
 

Carlos Danger

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It was also explained that this is a rare case where paralyzing the patient is encourage.
I never have and never will understand the reluctance in the transport community to use NMB. In nearly every case the advantages of it easily outweigh any downsides or risks.
 
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GMCmedic

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I never have and never will understand the reluctance in the transport community to use NMB. In nearly every case the advantages of it easily outweigh any downsides or risks.
I don't either. I'm just a small fish in a big pond.
 

StCEMT

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I never have and never will understand the reluctance in the transport community to use NMB. In nearly every case the advantages of it easily outweigh any downsides or risks.
I'm annoyed that I am losing paralytics at my new job. Once we switch to our own pharmacy, we won't have it. And we have a vent that is basically a BVM on a timer, so it's damn near useless for my 30+ minute transports and a spontaneously breathing patient.
 

Carlos Danger

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I'm annoyed that I am losing paralytics at my new job. Once we switch to our own pharmacy, we won't have it. And we have a vent that is basically a BVM on a timer, so it's damn near useless for my 30+ minute transports and a spontaneously breathing patient.
That's too bad. NMB just makes transporting vented patients easier and, I would argue, quite often safer. Over the years I've heard a couple different rationale for avoiding NMB, but I don't recall ever hearing one that made any sense at all to me. I think what it often comes down to is that the folks who write the CCT protocols want to mimic the way things are done in the ED/ICU/OR to whatever extent possible lest they are forced to admit that the inside of a CCT unit or helicopter is not, in fact, the same exact thing as a tertiary facility ICU.
 

StCEMT

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That's too bad. NMB just makes transporting vented patients easier and, I would argue, quite often safer. Over the years I've heard a couple different rationale for avoiding NMB, but I don't recall ever hearing one that made any sense at all to me. I think what it often comes down to is that the folks who write the CCT protocols want to mimic the way things are done in the ED/ICU/OR to whatever extent possible lest they are forced to admit that the inside of a CCT unit or helicopter is not, in fact, the same exact thing as a tertiary facility ICU.
I'll fully admit that I never have used them before on CCT runs. I have on many occasions had to adjust sedation doses and add on pain meds, but up to this point that has been adequate. Given the resources I have when I work in the city in the CCT truck, I'll admit I lean more towards not using them, but I'm not opposed to it either.

Now that I've gone from a Hamilton T1 as my primary vent to this pneuton (CMV and IMV modes) I'd absolutely be doing Vec and Ketamine at the minimum on any and every ventilated transport. I'm not a fan of the way it looks like things will be set up this summer, but I also understand the issues that need to be addressed before improvements can be made.
 

Tigger

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That's too bad. NMB just makes transporting vented patients easier and, I would argue, quite often safer. Over the years I've heard a couple different rationale for avoiding NMB, but I don't recall ever hearing one that made any sense at all to me. I think what it often comes down to is that the folks who write the CCT protocols want to mimic the way things are done in the ED/ICU/OR to whatever extent possible lest they are forced to admit that the inside of a CCT unit or helicopter is not, in fact, the same exact thing as a tertiary facility ICU.
Like why on earth does my medical director want vented patients to be maintained at a RASS of -2 during transport? What benefit does this convey in a transport environment? These questions remain unanswered except for "reduced ICU delirium." Sigh.
 

StCEMT

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Like why on earth does my medical director want vented patients to be maintained at a RASS of -2 during transport? What benefit does this convey in a transport environment? These questions remain unanswered except for "reduced ICU delirium." Sigh.
Ours wanted 0 to -1. I don't think anyone ever actually followed it, I know I absolutely didn't.
 

silver

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Like why on earth does my medical director want vented patients to be maintained at a RASS of -2 during transport? What benefit does this convey in a transport environment? These questions remain unanswered except for "reduced ICU delirium." Sigh.

Would you stay to titrate the patient back to their original RASS goal once you complete the transport?

Often sedation doesn't get adjusted for hours once a new accepting team or even oncoming bedside RN after shift change starts caring for the patient. As a result some of the hard work to reduce ICU length of stay, ventilator days, cognitive dysfunction, and delirium gets negated.
 

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