Impedance threshold devices

[leviathan]

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Is anyone using / considering using these in their service? We're involved in a study with these right now and the literature seems to support them, as well as our own data that have been compiled so far.

 

[pseudoknot]

The published literature seems to show only short-term benefits in humans so far, although I know the animal data was quite promising. Do you know of any better long-term survival effects?

My service isn't using it yet, but I'm not sure about others in the area.

 

[146233]

We're not using them; to my knowledge, no one in the immediate area is involved in any trials, either. The data do seem somewhat encouraging, though, although the only bits I've seen followed patients to 24 hours. I'd be interested to see what the long-term survivlal rate (hospital discharge, 3 months, 6 months, etc.) are. leviathan, I'll be interested to see what you all find. 🙂

 

[leviathan]

I swear I saw some articles out there that showed it improved survival to hospital discharge, but looking right now all I can see is that there is a better rate of survival in basically every study, but none a statistically significant one.

/removes foot from mouth

 

[deleted92121]

My EMS company is involved with the ROC (Resuscitation Outcome Consortium) and we are involved in two studies right now.

1. The use of a "puck" during CPR. It alerts us to depth and rate as well as time and ventilation. The biggest aspect is dealing with Analyze Early vs. Analyze Late. Obviously the main objective is to see if priming the heart for two minutes with CPR has a greater result in ROSC as opposed to shocking before two minutes of CPR.

2. We use the ITD (Impedance Threshold Device) on cardiac arrests. We cannot use them on Pediatrics, Pregnant Women, or Prisoners as well as Trauma arrests. If basically keeps the pressure from building in the chest and prevents the heart from being squeezed. We never know if the ITD we are using is a true, working one or if it is a dummy.

I will keep you up to date on the outcomes. Please feel free to ask any questions.

dxu

 

[leviathan]

My EMS company is involved with the ROC (Resuscitation Outcome Consortium) and we are involved in two studies right now.

1. The use of a "puck" during CPR. It alerts us to depth and rate as well as time and ventilation. The biggest aspect is dealing with Analyze Early vs. Analyze Late. Obviously the main objective is to see if priming the heart for two minutes with CPR has a greater result in ROSC as opposed to shocking before two minutes of CPR.

2. We use the ITD (Impedance Threshold Device) on cardiac arrests. We cannot use them on Pediatrics, Pregnant Women, or Prisoners as well as Trauma arrests. If basically keeps the pressure from building in the chest and prevents the heart from being squeezed. We never know if the ITD we are using is a true, working one or if it is a dummy.

I will keep you up to date on the outcomes. Please feel free to ask any questions.

dxu

Hi dxu,

We are involved with the ROC studies as well. Are you also doing the hypertonic saline study there?

 

[pianoman511]

My service started using them some time ago and we noticed a fairly dramatic increase in the number of patients who we got a pulse back on. In fact in a few instances a pulse was returned even after quite extended downtime (granted the patient did not survive w/ brain activity tho). Also, the studies do seem to support it's use and the pig studies were fairly convincing in terms of the increased coronary perfusion pressure.

 

[deleted92121]

Hi dxu,

We are involved with the ROC studies as well. Are you also doing the hypertonic saline study there?

From what I understand we are supposed to be getting it soon. Of course, we just got CPAP and the EZ-IO drill. Love 'em both. But the hypertonic saline will be great to have. We could have used it last night on this bad call we had. Can't wait to have it for trauma!

dxu

 

[leviathan]

From what I understand we are supposed to be getting it soon. Of course, we just got CPAP and the EZ-IO drill. Love 'em both. But the hypertonic saline will be great to have. We could have used it last night on this bad call we had. Can't wait to have it for trauma!

dxu

BP has to be < 70 to use it with a traumatic mechanism, or BP < 90 with a HR >108. Alternately it can be head trauma with GCS < 8.

Consequently we haven't had the best enrollment so far. Some stations predictably get a lot of HS enrollments, but many others don't.

 

[deleted92121]

BP has to be < 70 to use it with a traumatic mechanism, or BP < 90 with a HR >108. Alternately it can be head trauma with GCS < 8.

Consequently we haven't had the best enrollment so far. Some stations predictably get a lot of HS enrollments, but many others don't.

We had a 71 y/o M last night involved in a fall that resulted in a large skull fx to the occipital portion. On scene GCS was 7 with decorticate posturing and disconjugate gaze. BP was 100/p with Sinus Tach on the EKG. Large bore IV x 2 in both AC and almost 500cc of NSS brought BP up to 140/p. I tried to intubate but had intact gag so the flight crew did RSI...second attempt was successful for them.

dxu

 

[leviathan]

We had a 71 y/o M last night involved in a fall that resulted in a large skull fx to the occipital portion. On scene GCS was 7 with decorticate posturing and disconjugate gaze. BP was 100/p with Sinus Tach on the EKG. Large bore IV x 2 in both AC and almost 500cc of NSS brought BP up to 140/p. I tried to intubate but had intact gag so the flight crew did RSI...second attempt was successful for them.

dxu

Yeah he definitely could have used some mannitol, or hypertonic saline for that matter. 🙂

 

[deleted92121]

Yeah he definitely could have used some mannitol, or hypertonic saline for that matter. 🙂

haha...yeah he was one sick puppy. I will let you know his outcome when/if I hear.

dxu

 

[MedicFL]

Not trying to arm chair quarterback you here, but his BP was 100 you know it is probably a neuro issue why give the saline to raise it? In doing so you also raise the ICP? BP of 100 is not that bad.... Was there a large loss of blood?

 

[pseudoknot]

There is now a good deal of evidence showing that it is very bad to allow the BP to drop for any length of time in the context of TBI. Temporary hypoxia is much worse than temporary ICP increases.

Also, I thought mannitol was falling out of favor these days due to poor outcomes? A neurosurgeon giving a talk on TBI said that it's starting to look like a lot of the damage is mediated by widespread overstimulation of neurons, so probably ion channel blockers would be helpful (and presumably the hypertonic saline might not help).

 

[MedicFL]

HyperTonic saline came and went around here. I didn't know it was making a come back.. Mannitol is another one that I don't see used much anymore. What you are saying about TBI does make sense though but; at what point do you consider someones BP's too low? Is there a set target range that is being pushed? Being that this also involved trauma I would be cautious with pushing fluid on someone that had a BP of 100, now without what rate the ST was and all the other issues that go along with this case I am not going to make a judgment call here. I was just curious?

 

[deleted92121]

Okay, here comes my attempt to answer some of this.

1. MedicFL -- Pt had severe blood loss, maybe 1000cc. So we are dealing with hypovolemic shock. Mind you he has an open fx of the occipital portion with brain being exposed. While the hypotension could be related to the neuro deficit (GCS 7, therefore a classic TBI) we can do little in the field to correct that part other than do our best to control bleeding and replace lost fluid. Unfortunately, his initial SP02 was 70 and when you give that much fluid you are replacing a lot of that blood with NSS that cannot carry 02 and C02. We did however hyperventilate and it seemed to aid in controlling the bleeding. But no matter what, you are dammed if you do, dammed if you don't.

2. Pseudoknot -- I was presented with the same research findings as you. It seems really simple to say but in an emergency, no matter how lost you are, remember the ABC and the rest will come to you. Without an airway, you don't got crap. And you are correct with mannitol in the pre-hospital setting (my bread and butter) as we no longer carry it in our service.

3. MedicFL (again 😎) -- We have a neuro injury (decorticate posturing and disconjugate gaze with GCS 7) and we have a hemorrhage caused by traumatic event. We cannot do a whole lot to fix the neuro injury other than drive faster or lifeflight them to a trauma ctr. But we can attempt to control bleeding and replace fluid. ST was rate 120-130. Obviously there is a compensation mechanism in play here. The entire thing was a judgment call, from how much fluid to pump in to attempting intubation. EMS = think now, act now. We, like those in the ER, are forced to make very quick decisions at times and be confident in doing so. Just like your friendly neighborhood MD/DO or PA/NP, we can't always be certain of what the Pt outcome will be.

dxu

 

[leviathan]

Not trying to arm chair quarterback you here, but his BP was 100 you know it is probably a neuro issue why give the saline to raise it? In doing so you also raise the ICP? BP of 100 is not that bad.... Was there a large loss of blood?

Hypertonic saline is not given to head trauma for the purpose of volume resuscitation.

 

[pseudoknot]

Hypertonic saline is not given to head trauma for the purpose of volume resuscitation.

You're right of course, but I don't think dxu actually gave hypertonic saline, just regular isotonic unless I'm mistaken. I think MedicFL was wondering why dxu wasn't more conservative about fluid resuscitation because he was worried about causing increased ICP. As dxu and I have pointed out though, hypoxia is a much bigger worry (even/especially with TBI!).

I know you already know the latter, just trying to clarify MedicFL's question.

 

[leviathan]

You're right of course, but I don't think dxu actually gave hypertonic saline, just regular isotonic unless I'm mistaken. I think MedicFL was wondering why dxu wasn't more conservative about fluid resuscitation because he was worried about causing increased ICP. As dxu and I have pointed out though, hypoxia is a much bigger worry (even/especially with TBI!).

I know you already know the latter, just trying to clarify MedicFL's question.

My mistake, I forgot that he mentioned they are not running that protocol over there. Yes, especially since about 2/3 of 0.9% normal saline will end up in the interstitium, I'd be worried about elevating ICP as well.

 

[MedicFL]

Fair answer all I was getting at, around here a BP of 100 is considered ok and we really aren't supposed to push fluid boluses on that BP. But seeing the rest of the case ST 120-130, 1000cc blood loss I do understand. And you know what I retract the whole statement occipital Fx the brain can expand as it pleases so my whole concern goes out the window. I do agree with your treatment option, you are right sometimes we are limited in the field and are damned if we damned if we dont..

 

[pseudoknot]

My mistake, I forgot that he mentioned they are not running that protocol over there. Yes, especially since about 2/3 of 0.9% normal saline will end up in the interstitium, I'd be worried about elevating ICP as well.

It's a tough call of course, but I vaguely remember something to the effect that a single brief hypoxic (hypotensive?) event can lower survival in TBI by 50% (or maybe just 20? my brain is too full of neuroanatomy garbage right now). In PHTLS they were very adamant that BP shouldn't ever fall below 100 for a head injury.

Anyway, speaking of neuro, I have an exam on Friday so I'd better clear out of here for a bit...

 

[leviathan]

It's a tough call of course, but I vaguely remember something to the effect that a single brief hypoxic (hypotensive?) event can lower survival in TBI by 50% (or maybe just 20? my brain is too full of neuroanatomy garbage right now). In PHTLS they were very adamant that BP shouldn't ever fall below 100 for a head injury.

Reviving old thread, but interesting...in general I don't think hypotension is really going to a problem with head trauma, no? Also, are they sure it's 100? Cerebral blood flow is maintained constant between 80-160 mmHg, so anything above 80 should be good.

 

[deleted92121]

Reviving old thread, but interesting...in general I don't think hypotension is really going to a problem with head trauma, no? Also, are they sure it's 100? Cerebral blood flow is maintained constant between 80-160 mmHg, so anything above 80 should be good.

You would think so. The problem with hypotension in TBI is that it affects the bodys ability to regulate CPP and promotes greater ischemia. So one single episode of hypotension has a greater chance of permanently skewing the regulation of CPP as opposed to maintaining the BP at or around 100-110 systolic. Not saying that every person with a TBI that has a hypotensive episode will end up with a lifetime (albeit a short one probably) of fluctuating ICP.

dxu

 

[pseudoknot]

Reviving old thread, but interesting...in general I don't think hypotension is really going to a problem with head trauma, no? Also, are they sure it's 100? Cerebral blood flow is maintained constant between 80-160 mmHg, so anything above 80 should be good.

My earlier recollection was close: one or more episodes of prehospital hypotension (SBP < 90) double the risk of death after severe TBI. For a good review see:

J Trauma. 1997 May;42(5 Suppl):S4-9.
Avoidance of hypotension: conditio sine qua non of successful severe head-injury management.

Chesnut RM.
Department of Neurosurgery, Oregon Health Sciences University, Portland 97201-3098, USA.
PMID: 9191689

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