Another study on prehospital intubation

[Carlos Danger]

Is Prehospital Endotracheal Intubation Associated with Improved Outcomes In Isolated Severe Head Injury? A Matched Cohort Analysis.

Abstract:

Introduction Prehospital endotracheal intubation (ETI) following traumatic brain injury in urban settings is controversial. Studies investigating admission arterial blood gas (ABG) patterns in these instances are scant. Hypothesis Outcomes in patients subjected to divergent prehospital airway management options following severe head injury were studied.

METHODS:
This was a retrospective propensity-matched study in patients with isolated TBI (head Abbreviated Injury Scale (AIS) ≥ 3) and Glasgow Coma Scale (GCS) score of ≤ 8 admitted to a Level 1 urban trauma center from January 1, 2003 through October 31, 2011. Cases that had prehospital ETI were compared to controls subjected to oxygen by mask in a one to three ratio for demographics, mechanism of injury, tachycardia/hypotension, Injury Severity Score, type of intracranial lesion, and all major surgical interventions. Primary outcome was mortality and secondary outcomes included admission gas profile, in-hospital morbidity, ICU length of stay (ICU LOS) and hospital length of stay (HLOS).

RESULTS:
Cases (n = 55) and controls (n = 165) had statistically similar prehospital and in-hospital variables after propensity matching. Mortality was significantly higher for the ETI group (69.1% vs 55.2% respectively, P = .011). There was no difference in pH, base deficit, and pCO2 on admission blood gases; however the ETI group had significantly lower pO2 (187 (SD = 14) vs 213 (SD = 13), P = .034). There was a significantly increased incidence of septic shock in the ETI group. Patients subjected to prehospital ETI had a longer HLOS and ICU LOS.

CONCLUSION:
In isolated severe traumatic brain injury, prehospital endotracheal intubation was associated with significantly higher adjusted mortality rate and worsened admission oxygenation. Further prospective validation of these findings is warranted. Karamanos E , Talving P , Skiada D , Osby M , Inaba K , Lam L , Albuz O , Demetriades D . Is prehospital endotracheal intubation associated with improved outcomes in isolated severe head injury? A matched cohort analysis. Prehosp Disaster Med. 2013;28(6):1-5 .

This is a very interesting study that appeared in the December issue of Prehospital and Disaster Medicine. It challenges the conventional wisdom concerning prehospital intubation of TBI patients, and appears to support the position of those who oppose prehospital intubation.

Researchers from the Division of Acute Care Surgery at UCLA retrospectively analyzed the charts of 1,105 patient who were admitted with isolated severe TBI (AIS +/>3, and/or GCS +<8) during an 8-year study period. 847 of those patients met all inclusion criteria, one of which was having an arterial blood gas sample drawn upon ED arrival. Rigorous propensity matching resulted in a cohort of 55 patients who were intubated in the field compared to a well-matched control group of 165 who were not. The primary outcome was mortality and secondary outcomes included admission blood gas profile, morbidity, and ICU and hospital lengths of stay.

The primary outcome result was not particularly surprising, though disappointing: patients intubated in the field were significantly more likely to die than those who were not intubated in the field (69.1% vs 55.2%). More interesting, though, were two of the secondary outcomes: admission blood gases between the two groups were the same, with the exception a slightly lower Pa02 in the intubated patients vs. the non-intubated ones (187 mmHg vs. 213 mmHg). The incidence of pneumonia was exactly the same between the two groups: 5.5%. Intubated patients had higher rates of septic shock (14.5% vs. 4.2%).

This study convincingly calls into question the very rationale upon which prehospital intubation of head injured patients is based: the need to secure the airway and the need to control ventilation. With identical rates of pneumonia, aspiration was apparently not a problem in the non-intubated patients, and with the same BE, pH, and C02 levels and higher oxygen tensions in the non-intubated patients, ventilation and oxygenation was apparently not a problem in the non-intubated patients.

This is far from the first study to show worse outcomes in patients who are intubated in the field, and a common hypothesis has been that patients who are intubated are hyperventilated during transport (I have read of studies that found very low PaC02's on ED arrival in prehospitally-intubated patients, but I cannot find a reference right now). This study, however, shows that C02 tension does not necessarily tell the whole story.

The Brain Trauma Foundation has long taught that even brief episodes of hypotension or hypoxemia will dramatically increase mortality in TBI patients. In my experience, hypotension and hypoxemia are not at all uncommon during prehospital RSI's, and while these insults are usually transient, they are often severe.

Poor control of hemodynamics and prevention of hypoxemia during and immediately after field intubation seems a likely explanation for the worsened outcomes.

 

[unleashedfury]

In my experience, hypotension and hypoxemia are not at all uncommon during prehospital RSI's, and while these insults are usually transient, they are often severe[/B].

Poor control of hemodynamics and prevention of hypoxemia during and immediately after field intubation seems a likely explanation for the worsened outcomes.

That's my question RSI.

a lot of TBI patients with a GCS score creeping around the magical 8 ball number end up RSI'd, If there is a problem during RSI, what was it *difficult airway, lack of proficiency in skill, equipment problem* was it appropriately documented. What about hyperoxgenation of your patient prior to a intubation attempt. using your Airway Scores LEMON, or which ever pneumonic you choose, if they are breathing on their own adequately why can't a NRB suit them. The other issue using GCS scores is its provider accuracy, What I might call a GCS of 8, You might call a 6, Or a 10. There needs to be a better indicator for justifying what the criteria for Intubation needs to be.

Hyperventilation and Gastric distension tend to play hand in hand so a OPA can lead to vomiting and aspiration. and obviously with a head injury the NPA is out the window.

 

[medicsb]

The findings are not surprising considering the EMS system by which the patients were treated. There is no RSI, correct? So any patient that was able to be intubated likely is pretty sick - little to no airway reflexes present, or a significant amount of "brutane" is being applied. As this was retrospective, there is likely a number of different factors that were not assessed that likely could have contributed to increased M&M, of which ETI could be associated. Another consideration is the EMS system itself. How much initial airway training does the average paramedic receive? How often does the average paramedic attempt ETI? How often are they successful? I'm going to guess that the average paramedic student gets <10 tubes, that the average medic gets <5 tubes a year, and that their overall success is <90%. All of that creates a perfect storm for poor outcomes.

So... poorly trained and poorly experienced intubators produce poor outcomes? No sh*t.

And sadly, I doubt that this is deviation from the norm. This likely could be extrapolated to many, if not most, EMS systems in the US.

 

[Smash]

What medicsb said.

This is yet another "study" that purports to show that prehospital intubation is the root of all evil. It's utter rubbish. Prehospital intubation isn't bad, it's prehospital intubation done badly that is bad.

 

[Carlos Danger]

This is yet another "study" that purports to show that prehospital intubation is the root of all evil. It's utter rubbish. Prehospital intubation isn't bad, it's prehospital intubation done badly that is bad.

Where in this paper did the authors claim that prehospital intubation is the root of all evil? Cuz I missed that part somehow....

Some would say that this type of outright dismissal of anything that doesn't support what one wishes to be the truth is exactly why EMS is where it's at.

And just to follow your reasoning, where is the evidence that prehospital intubation "done WELL" is beneficial to patients? And how do you even define "done well"?

This study is far from rubbish, in fact it is very well done. I read studies on airway management all the time, but rarely do I come across one as well done and as pertinent to EMS practice as this one. Is it perfect? No - what study is? The point is that it presents some valuable and interesting insights that have not been presented before - at least not as far as I know.

If this paper contradicted lots of other research, then there might be some rationale behind assuming that it is "rubbish". But as I wrote before, this is far from the first study that shows poorer outcomes when patients are intubated prehospital. All this research really did was support what lots of other research has already told us, PLUS give us some potentially valuable insight into why the state of the art is what it is.

 

[Smash]

Where in this paper did the authors claim that prehospital intubation is the root of all evil? Cuz I missed that part somehow....

Some would say that this type of outright dismissal of anything that doesn't support what one wishes to be the truth is exactly why EMS is where it's at.

Fortunately EMS is nowhere near where this is at in my shop. We RSI frequently and well, in the last quarter performing over 200 drug facilitated intubations with 100% success. We also do not allow patients to become hypoxia, hypocapnic, hypercapnic or hypotensive while we are doing it. Our refusal to accept junk science is part of the reason we do what we do so well.

And just to follow your reasoning, where is the evidence that prehospital intubation "done WELL" is beneficial to patients? And how do you even define "done well"?

Bernard's RSI trial. An actual randomised, intention to treat study that, in spite of the prehospital arm being more severely injured, improved long term functional outcomes in the patients intubated in the field. There are also am increasing number of studies from other places that show that field intubation can be performed as effectively and safely as in hospital if it is done well, such as the article by Chester et al in EMJ this month.

This study is far from rubbish, in fact it is very well done. I read studies on airway management all the time, but rarely do I come across one as well done and as pertinent to EMS practice as this one. Is it perfect? No - what study is? The point is that it presents some valuable and interesting insights that have not been presented before - at least not as far as I know.

If this paper contradicted lots of other research, then there might be some rationale behind assuming that it is "rubbish". But as I wrote before, this is far from the first study that shows poorer outcomes when patients are intubated prehospital. All this research really did was support what lots of other research has already told us, PLUS give us some potentially valuable insight into why the state of the art is what it is.

This is just one more study in a long line of studies that shows the same thing. From the San Diego study, through every Henry Wang study, to this one, we see the same thing. Poorly educated, poorly trained, inexperienced practitioners intubating with the wrong tools, or in patients so sick as to be absent of airway reflexes, cause bad outcomes.

This is hardly news, and this study does nothing to add to the body of knowledge; it is merely more fuel to the fire for those that would rather not address the root causes of the problems in EMS.

 

[medicsb]

Some would say that this type of outright dismissal of anything that doesn't support what one wishes to be the truth is exactly why EMS is where it's at.

And just to follow your reasoning, where is the evidence that prehospital intubation "done WELL" is beneficial to patients? And how do you even define "done well"?

Stephen Bernard et al. Prehospital Rapid Sequence Intubation Improves Functional Outcome for Patients With Severe Traumatic Brain Injury: A Randomized Controlled Trial. Ann Surg 2010;252:959–965.

Randomised and controlled - BVM vs. RSI. Can't get much more robust of a design.

97% overall success for patients administered RSI drugs? There are few ground services in the US that can reach that (and I would not doubt that many flight services do not reach 97%). Considering how few paramedics are allowed to intubate in Australia, I have little reason to believe that they are not well experienced (and probably well trained and educated to start).

This study is far from rubbish, in fact it is very well done. I read studies on airway management all the time, but rarely do I come across one as well done and as pertinent to EMS practice as this one. Is it perfect? No - what study is? The point is that it presents some valuable and interesting insights that have not been presented before - at least not as far as I know.

Not saying it isn't well done or that the methodology is poor or whatever. But the most important factor, the intubator, is ignored, and largely has been ignored in studies of prehospital intubation. You cannot discount the training and experience of the paramedics, especially when it comes to airway management. If they get poor training and get little experience once working, then it should be expected that they are not going to be good at the procedure, and thus patient outcomes will suffer. As some say: Garbage in, garbage out.

Do you honestly think that if this study was done in Europe, where physicians (often anesthesiologists) are the ones doing prehospital airway management, that the results would be the same?

 

[medicasaurus]

"PREHOSPITAL RSI AS SAFE AS HOSPITAL RSI"

http://www.scancrit.com/2014/01/05/prehospital-rsi-safe-hospital-rsi/

Key thing is "When done right"

 

[Carlos Danger]

Stephen Bernard et al. Prehospital Rapid Sequence Intubation Improves Functional Outcome for Patients With Severe Traumatic Brain Injury: A Randomized Controlled Trial. Ann Surg 2010;252:959–965.

Randomised and controlled - BVM vs. RSI. Can't get much more robust of a design.

97% overall success for patients administered RSI drugs? There are few ground services in the US that can reach that (and I would not doubt that many flight services do not reach 97%).

Considering how few paramedics are allowed to intubate in Australia, I have little reason to believe that they are not well experienced (and probably well trained and educated to start).

Exactly the point. How does a trial done in Australia by a small group of very highly trained clinicians extrapolate to the US systems? It doesn't at all; it's apples & oranges. Other than, perhaps, to tell us that our paramedics shouldn't be intubating until they get a lot more education and experience. I think that is the obvious lesson in all the negative outcomes of the research done in the US, and is what I and many others have been saying all along.

The reason I personally find the study I posted interesting is the fact that there was no difference in blood gases between the two groups. This essentially blows out of the water the frequently touted excuse that "it's not the intubation, it's the lack of transport ventilators that is harming the intubated patients". It also blows out of the water the ideas that these patients are unable to ventilate appropriately, and that they're sure to aspirate if they aren't intubated.

"PREHOSPITAL RSI AS SAFE AS HOSPITAL RSI"

http://www.scancrit.com/2014/01/05/prehospital-rsi-safe-hospital-rsi/

Key thing is "When done right"

As far as I can tell from the abstract (I have to wait for the library to send me the pdf; I can't access the whole article online for some reason), this study simply shows a 100% success rate with 88 prehospital RSI attempts. While I congratulate this program on a successful rollout of their RSI protocol, 88 successes is not exactly earth-shatteringly impressive.

It also does nothing to support the blogger's assertion that it provides "evidence of superiority of the doctor-paramedic model in prehospital care", because there are probably dozens of HEMS programs in the US flying RN-paramedic or RN-RN who can show a 100% success rate over a series of many more than 88 RSI attempts.

You also can't necessarily equate "successful placement" to "safety". In the study I posted for example, all the intubated patients were successfully intubated, but still had worse outcomes than those who weren't.

 

[medicsb]

Exactly the point. How does a trial done in Australia by a small group of very highly trained clinicians extrapolate to the US systems? It doesn't at all; it's apples & oranges. Other than, perhaps, to tell us that our paramedics shouldn't be intubating until they get a lot more education and experience. I think that is the obvious lesson in all the negative outcomes of the research done in the US, and is what I and many others have been saying all along.

You're right in that it doesn't extrapolate to most US systems. The way you framed your original post was by saying that the current study is challenging "conventional wisdom" of prehospital ETI for head injury, implying that ETI in and of itself is bad. You did not put it in the context of the US or more specifically of EMS systems such as that in LA.

To me, the current study is not surprising for reasons I mentioned previously.

The reason I personally find the study I posted interesting is the fact that there was no difference in blood gases between the two groups. This essentially blows out of the water the frequently touted excuse that "it's not the intubation, it's the lack of transport ventilators that is harming the intubated patients". It also blows out of the water the ideas that these patients are unable to ventilate appropriately, and that they're sure to aspirate if they aren't intubated.

As far as the ABGs, I'm not particularly moved. I would say, based on past observations of hyperventilation of prehospital head injured patients being a problem, that maybe some services have learned and are now closely watching ventilation rates. That's good. But, the study (I don't have full text access) appears to only look at variables measured at hospital arrival. We have no way of knowing what occurred prior or during intubation that could be influencing outcomes. ABG is not going to capture hypercarbia or hypoxia that occurs during or before ETI.

So, now we can say that it is the intubation? Great. Then now it's time for most US paramedics to stop intubating altogether. But, of course, everyone will try and explain how their system is not like the system studied - cue the "but, our medical director is friends with us and sits down and shows us how to intubate on manikins and then takes us out for beers", or "we have to tube a manikin every shift", or "our QA/QI is SOOO robust", or whatever. But, the thing is that the overwhelming majority of EMS systems have high numbers of paramedics who intubate and some of those systems also allow RSI. Most of those paramedics do not intubate with enough frequency to be proficient.

"evidence of superiority of the doctor-paramedic model in prehospital care", because there are probably dozens of HEMS programs in the US flying RN-paramedic or RN-RN who can show a 100% success rate over a series of many more than 88 RSI attempts.

I would actually doubt that. Maybe 20 years ago, but considering how much the aeromedical industry has been diluted, I'd be surprised if there were more than a half dozen that could achieve 100% success for 88 patients. But, I'd be happy to be wrong.

 

[Carlos Danger]

I would actually doubt that. Maybe 20 years ago, but considering how much the aeromedical industry has been diluted, I'd be surprised if there were more than a half dozen that could achieve 100% success for 88 patients. But, I'd be happy to be wrong.

Certainly not every program, perhaps not even a majority of them, but there are quite a few that have really excellent rates of success. My last program was looked at by the trauma service at our primary receiving hospital and found to have a 96.2% success rate with intubation (329 of 342 attempts, with all unsuccessfully intubated airways successfully managed with an LMA) over I think a 3 year period. I suppose that probably isn't 88 consecutive successful intubations, but I also don't doubt that there are some programs who have better numbers than ours, and these are intubations that were often done after ground EMS had made several unsuccessful attempts - I'm not sure how that factors in as far as comparing to the program in the other study.

There is no doubt that intubation can successfully be done in the field. The problem is that it usually isn't.

 

[triemal04]

I'm not trying to detract from that at all (96.2% is extremely good), but is that looking at the first pass success rate, subsequent pass success rate, or overall success rate? While still impressive, the distinction should be made, especially in light of the fact that most problems with intubation come up when the attempt is prolonged.

I love and hate studies like this.

I love them because they show, yet again, that if people are not properly taught how to intubate and then intubate regularly enough to maintain their skills, that they should not be intubating patients, alive or dead. That's just plain old common sense.

I hate them because to many people don't take that meaning away from them, and instead decide "paramedics shouldn't intubate" instead of "paramedics need to be truly taught how to intubate, and utilized in a manner in which they will have the opportunity to do so."

If things don't take a dramatic shift, the day is coming, (and should come sooner rather than later) that intubation will no longer be a part of whatever standardized paramedic curriculum and scope exists; individual services that have the ability to do things differently and back up their practices with data and numbers may do differently, but as a whole it will be a vanished skill.

 

[Carlos Danger]

I'm not trying to detract from that at all (96.2% is extremely good), but is that looking at the first pass success rate, subsequent pass success rate, or overall success rate? While still impressive, the distinction should be made, especially in light of the fact that most problems with intubation come up when the attempt is prolonged.

I don't know if they dug as deep as looking at number of attempts. I suspect not, but then again they must have looked at the charts in some depth so maybe they did take that into account. To be honest I'd be surprised if we intubated 96% on the very first try.

I don't know how much I think we should really stress the importance of first-pass success rates. I know an increasing number of attempts is associated with worse outcomes, and of course it makes sense to do whatever you can do to maximize your chances on the first try, but if you are having a hard time getting a good view there is no shame in pulling out and ventilating BEFORE the sats drop....in fact that is absolutely the right thing to do. I think by stressing the importance of getting the tube on the first try, we are inadvertently encouraging attempts that last longer than they should.

.

 

[triemal04]

While it doesn't necessarily need to be recorded in every study looking at intubation, any department that tracks their intubation success/failure rate (as any that is intubating really should) ought to be tracking the number of attempts.

If a study using that data every is published, depending on the goal, knowing how many attempts were needed may be important in drawing an accurate conclusion, as would knowing if there were any adverse events during the multiple attempts.

While the internal focus within a department shouldn't be heavy enough on first-pass success that people fail to back out as needed, knowing that they had to, and WHY they had to matters for continuing QA and training; if there is a 50% overall first pass success rate and a 90% overall second pass success rate, what is being done wrong the first time? Highlighting deficiences in training and education is much easier when all the information is known.

Knowing the number of attempts also allows a department to ensure that people aren't taking an uneccesary number of attempts and increasing the risk to the patient.

Intubation is, in my opinion, going to be gone at some point in the career of most people here; if any department is going to try and maintain it for themselves, the only way to do so safely is to have as much info as possible about the proficiency of their medics, and years of results to back that up.

 

[KingCountyMedic]

Gage and DeSoto came here in 1978 and saw firsthand the RIGHT way to do things and California still hasn't gotten it right!

I'm not surprised by any of these studies that they keep putting out. You gotta do something a lot to be good at it. This is impossible when you have too many Paramedics and not enough sick people. I've seen a lot of good thoughts in this thread. Good read. Cheers:beerchug:

 

[NomadicMedic]

Gage and DeSoto came here in 1978 and saw firsthand the RIGHT way to do things and California still hasn't gotten it right!

I just watched that the other day. http://youtu.be/oMUyiBhNJf8