# IO vs IV for cardiac arrest: recently published research



## medicsb (Jan 13, 2018)

*No definitive answers as these are retrospectives analyses, but these articles raise questions that should have been answered before the movement toward "IO first" in cardiac arrest that many services have adopted.  *

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*Intraosseous Vascular Access Is Associated With Lower Survival and Neurologic Recovery Among Patients With Out-of-Hospital Cardiac Arrest*
*Presented at the Canadian Association of Emergency Physicians congress, June 2017, Whistler, Canada.*

*Study objective*

We seek to determine the effect of intraosseous over intravenous vascular access on outcomes after out-of-hospital cardiac arrest.

*Methods*
This secondary analysis of the Resuscitation Outcomes Consortium Prehospital Resuscitation Using an Impedance Valve and Early Versus Delayed (PRIMED) study included adult patients with nontraumatic out-of-hospital cardiac arrests treated during 2007 to 2009, excluding those with any unsuccessful attempt or more than one access site. The primary exposure was intraosseous versus intravenous vascular access. The primary outcome was favorable neurologic outcome on hospital discharge (modified Rankin Scale score ≤3). We determined the association between vascular access route and out-of-hospital cardiac arrest outcome with multivariable logistic regression, adjusting for age, sex, initial emergency medical services–recorded rhythm (shockable or nonshockable), witness status, bystander cardiopulmonary resuscitation, use of public automated external defibrillator, episode location (public or not), and time from call to paramedic scene arrival. We confirmed the results with multiple imputation, propensity score matching, and generalized estimating equations, with study enrolling region as a clustering variable.

*Results*
Of 13,155 included out-of-hospital cardiac arrests, 660 (5.0%) received intraosseous vascular access. In the intraosseous group, 10 of 660 patients (1.5%) had favorable neurologic outcome compared with 945 of 12,495 (7.6%) in the intravenous group. On multivariable regression, intraosseous access was associated with poorer out-of-hospital cardiac arrest survival (adjusted odds ratio 0.24; 95% confidence interval 0.12 to 0.46). Sensitivity analyses revealed similar results.

*Conclusion*
In adult out-of-hospital cardiac arrest patients, intraosseous vascular access was associated with poorer neurologic outcomes than intravenous access.

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The Effect of IV vs. IO Access in Prehospital Cardiac Arrest ROSC Rates

*Colby Redfield, Stephen Suarez, Jessica Daniels, Cristina Sanchez, Heidi Siples, Kim Landry*, _Leon County EMS_ Category of Submission: Cardiac

*Background*: The prevailing standard of care in prehospital emergency medical services is that either intravenous (IV) or intraosseous (IO) are acceptable routes for obtaining vascular access and delivery of resuscitation medications and volume expanders in cardiac arrest patients. Our local EMS agency's current cardiac arrest protocol allows for either IV or IO access to be placed without preference. Objective: To evaluate the effectiveness of IV access versus IO access, in terms of Return of Spontaneous Circulation (ROSC), for patients suffering from cardiac arrest. *Methods*: Quality Improvement retrospective review project examining cardiac arrest data with a single ACLS EMS agency with average call volume of 37,000 calls annually. We examined a four year period from 2013 to 2016. Cardiac Arrest patients were identified from a Quality Assurance Database. Exclusion criteria included trauma arrest, pediatrics, pregnancy, and obvious signs of death. Method of vascular access was determined by reviewing the report and placed into an excel spreadsheet along with ROSC determination. *Results*: A total of 1,028 patient care reports were examined from January 1, 2013 to December 31, 2016. There were 230 patients where resuscitation was not initiated due to obvious signs of death. A total of 46 patients were excluded as trauma related cardiac arrests and 31 patients excluded due to age less than 18 years. A total of 721 patients remained after applying the exclusion criteria. A total of 361 cardiac arrest patients had an IV placed with a ROSC in 148 (41.1%). A total of 360 cardiac arrest patients had an IO placed with a ROSC in 80 (22.2%). IV use during cardiac arrest had improved ROSC when compared to IO use (p < 0.001). *Conclusions*: In this small retrospective review, there is a correlation between higher ROSC rates and IV access versus IO access. Limitations include small sample size, single EMS agency and retrospective nature of study. Future studies should further evaluate the effectiveness of IO vs IV access in cardiac arrest and other low perfusion states such as shock in a prospective manner.

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Resuscitation. 2017 Aug;117:91-96. 
*Intraosseous compared to intravenous drug resuscitation in out-of-hospital cardiac arrest.*
Feinstein BA1, Stubbs BA2, Rea T3, Kudenchuk PJ4.
*Author information*
*Abstract*
*AIMS: *
Although the intraosseous (IO) route is increasingly used for vascular access in out-of-hospital cardiac arrest (OHCA), little is known about its comparative effectiveness relative to intravenous (IV) access. We evaluated clinical outcomes following OHCA comparing drug administration via IO versus IV routes.

*METHODS: *
This retrospective cohort study evaluated Emergency Medical Services (EMS)-treated adults with atraumatic OHCA in a large metropolitan EMS system between 9/1/2012-12/31/2014. Access was classified as IO or IV based on the route of first EMS drug administration. Study endpoints were survival to hospital discharge, return of spontaneous circulation (ROSC) and survival to hospital admission.

*RESULTS: *
Among 2164 adults with OHCA, 1800 met eligibility criteria, 1525 of whom were treated via IV and 275 principally via tibial-IO routes. Compared to IV, IO-treated patients were younger, more often women, had unwitnessed OHCA, a non-cardiac aetiology, and presented with non-shockable rhythms. IO versus IV-treated patients were less likely to survive to hospital discharge (14.9% vs 22.8%, p=0.003), achieve ROSC (43.6% vs 55.5%, p<0.001) or be hospitalized (38.5% vs 50.0% p<0.001). In multivariable adjusted analyses, IO treatment was not associated with survival to discharge (odds ratio (OR) (95% confidence interval) 0.81 (0.55, 1.21), p=0.31), but was associated with a lower likelihood of ROSC (OR=0.67 (0.50, 0.88), p=0.004) and survival to hospitalization (OR=0.68 (0.51, 0.91), p=0.009).

*CONCLUSION: *
Though not independently associated with survival to discharge, principally tibial IO versus IV treatment was associated with a lower likelihood of ROSC and hospitalization. How routes of vascular access influence clinical outcomes after OHCA merits additional study.


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## RocketMedic (Jan 13, 2018)

Eh...

Most IOs go into arrested patients, who tend to be asystolic, obese or otherwise challenging patients to quickly gain access in. I dont think there's a profound connection here. I do think IO is underused in periarrest patients when IV is difficult or impossible.


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## COmedic17 (Jan 14, 2018)

Well logically, it makes sense. 

For someone without a pulse, who is receiving cpr, which do you think is going to perfuse better? An EJ which is close to their core? Or a tibial io? When doing good CPR are you more likely to feel a carotid pulse or a pedal pulse? 

In all honesty, I feel most providers assume they won't be able to find a line so they go for the IO. We try IV access before going to the IO and I would say 80% of the time, an EJ or other vascular access ( AC, etc)  is easily obtainable. Have someone push on their liver while someone is doing CPR and they will almost always pop right up. And they don't fight the EJ either, so it's the easiest line ever.


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## DesertMedic66 (Jan 14, 2018)

So more of the IO patients were unwitnessed OCHA and also had non-shockable initial rhythms compared to the IV group. If only witnessed OCHA and shockable initial rhythms were shown to greatly improve ROSC.


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## reaper (Jan 14, 2018)

This study is absolutely useless. It takes no variables into account. Hell,  they might as well looked at what color underwear each pt was wearing at the time.


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## Carlos Danger (Jan 14, 2018)

reaper said:


> This study is absolutely useless. It takes no variables into account. Hell,  they might as well looked at what color underwear each pt was wearing at the time.



They aren't useless, because they raise some good questions, if nothing else.

The first thing that needs to be answered is "why did the IO patients get IO rather than IV"? Because as others have said, it could very well be that the IO's were placed in people with worse general health status to begin with and that's why they did worse. The second analysis even said that the IO patients were more likely to have suffered unwitnessed arrests and present with non-shockable rhythms. Keep in mind that without IO access, some (if not most, depending on the reason the IO was used) of these patients may not have had any access at all. 

The next step would be to compare a much larger number of patients who receive IO to a similar number of patients who received IV, but take the IO sample from a system than ALWAYS does IO first in cardiac arrest and the IV sample from a separate EMS system that always attempts IV's first. Ensure that both EMS systems are otherwise similar in their cardiac arrest protocols, response times, transport to times, and overall success rates. You'll still have the problem of the IV patients possibly being healthier and therefore having better chances of a good outcome, but I think with this design you'd have controlled for that as well as possible. There's probably no way to do a RCT on this.


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## FiremanMike (Jan 14, 2018)

RocketMedic said:


> Eh...
> 
> Most IOs go into arrested patients, who tend to be asystolic, obese or otherwise challenging patients to quickly gain access in. I dont think there's a profound connection here. I do think IO is underused in periarrest patients when IV is difficult or impossible.



That was my immediate reaction as well..


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## E tank (Jan 14, 2018)

Hard to get anything at all from a couple of abstracts of observational studies. That said, selection bias is a known hazard with these types of papers, a fact that couldn't have been lost on the authors.  

If I had to guess, the idea is to raise the question as to the utility of frogging around with futile vascular access then going to IO in these particular patients. IO access just being a surrogate for "they're taking too much time".


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## medicsb (Jan 14, 2018)

Some valid points brought up (though there seems to be a weird tendency among some here to assume that the authors didn't think of biases associated with the study design, results, etc. and somehow attempt to control for such biases or acknowledge such.)  These studies ARE limited by design, and it is tough to draw good conclusions (y'know, what I acknowledged in the original post), but they should make us reconsider our practices.  

I posted these because it has been obvious that there has been a general tendency to place IOs sooner than later, and many (here on EMTLIFE, especially) espouse immediate (or early) IO over IV attempts with the thought being that quicker vascular access is ideal for medication/fluid delivery.  My experience in my locale is that IOs are more often placed than IVs in cardiac arrest despite patients often having good peripheral veins available (proven when the RN or resident/doc quickly gets a peripheral line).  

I suspect that these studies will be used as a catalyst for a RCT.


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## DesertMedic66 (Jan 14, 2018)

medicsb said:


> My experience in my locale is that IOs are more often placed than IVs in cardiac arrest despite patients often having good peripheral veins available (proven when the RN or resident/doc quickly gets a peripheral line).


Hardly proven when they are able to get an IV. By the time these patients get to the ED we have already started treatments such as volume replacement and other treatments that will make IV access much easier at that point.


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## Djohnson (Jan 15, 2018)

I would have to agree that there are too many variables and possible reasons for the IO vs IV in each specific case to come to a definitive conclusion. Extended down time, obese patients, patients with medical problems causing poor vasculature, who knows. There is a strong possibility that if a patient requires an IO, then their neurological outcome may be worse due to the underlying issue. If nothing else, at least the study makes us think a little bit more about what our treatment options are and the "why"s associated with them.


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## EpiEMS (Jan 15, 2018)

medicsb said:


> correlation between higher ROSC rates and IV access versus IO access



Interesting stuff - hadn't seen this before!



Remi said:


> There's probably no way to do a RCT on this.



Definitely not possible to be blind, but why couldn't even weeks get IOs and odd weeks get IVs (or something)? That would be pretty good.


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## COmedic17 (Jan 17, 2018)

How many of you try IV access before going straight to an IO?  Because you assume it will be difficult to obtain IV access due to cardiac arrest, obesity, etc. 

Be honest. 

Because I hear a lot medics talk about how frequently they do IOs on cardiac arrests. Out of the 6 or 7 cardiac arrests I have had in the last year, I have started 1 IO. And after the IO, I was still able to get an IV enroute. And these were not arrests of 30 year olds with awesome vascular access. If you start IO's on these patients more then IVs, I have to assume you either are not great at obtaining IV's to begin with, or you reach straight for the IO without trying. 

And I have totally been there. I have worked places where it was common practice to assume an IO would be more time efficient and I wouldn't be able to find a good line anyways, but now that I work in a place that practices the opposite, I have found an iv is more often then not, easily obtainable.


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## EpiEMS (Jan 17, 2018)

COmedic17 said:


> If you start IO's on these patients more then IVs, I have to assume you either are not great at obtaining IV's to begin with, or you reach straight for the IO without trying.



Fortunately, ACLS drugs (probably, and epinephrine in particular) don't make a difference for neurologically intact survival.

On the side of IOs vs. IVs, there is a lot to be said for why IOs are better (example) - namely ease of use...so if we are just trying to get useless drugs in, why not choose the easier path


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## COmedic17 (Jan 17, 2018)

EpiEMS said:


> Fortunately, ACLS drugs (probably, and epinephrine in particular) don't make a difference for neurologically intact survival.
> 
> On the side of IOs vs. IVs, there is a lot to be said for why IOs are better (example) - namely ease of use...so if we are just trying to get useless drugs in, why not choose the easier path


What? 

I can get an IV in just as easily and quickly as an IO. Often times quicker. And they flow much better/quicker. So I am confused as to what you are talking about. 

While epi hasn't been proven to change much, your forgetting every other potential cardiac arrest drug (depending on circumstances)..... like narcan, dextrose, mag sulfate, calcium, bicarb.....

Your thought process of "pushing meds is useless, so who cares about the efficiency of the access" is somewhat concerning.


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## EpiEMS (Jan 17, 2018)

COmedic17 said:


> I can get an IV in just as easily and quickly as an IO. Often times quicker. And they flow much better/quicker. So I am confused as to what you are talking about.



You might be able to get IV access as fast as you can IO, but most providers cannot. Yes, there may be a flow rate advantage, but is it *clinically *significant?



COmedic17 said:


> While epi hasn't been proven to change much, your forgetting every other potential cardiac arrest drug (depending on circumstances)



No vasopressor or antiarrythmic, as far as I know, has been shown to increase ROSC. Same goes for calcium and bicarb. (Narcan, dextrose, sure - fair point.)


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## DesertMedic66 (Jan 17, 2018)

COmedic17 said:


> What?
> 
> I can get an IV in just as easily and quickly as an IO. Often times quicker. And they flow much better/quicker. So I am confused as to what you are talking about.
> 
> ...


Uhhhh.... narcan and dextrose aren’t cardiac arrest drugs..


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## DrParasite (Jan 17, 2018)

DesertMedic66 said:


> Uhhhh.... narcan and dextrose aren’t cardiac arrest drugs..


not even for an opiod OD/cardiac arrest?or a hypoglycemia cardiac arrest?

I'm curious how an IV (apply tourniquet, find good vein, stick good vein, hope it doesn't clot or collapse on you) takes less time than and IT (put IO needed here, press trigger, make whirrrrrr noise, attach tubing).


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## VFlutter (Jan 17, 2018)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786250/
I have a feeling selection bias is a major contributor to IO patients having worse outcomes.

For the vast majority of providers EZ-IO will be faster than peripheral IV access and is probably a good first line choice for cardiac arrest. IO for initial resuscitation then PIV as quickly as able after.

There have been multiple studies, both military and civilian, about IO vs IV insertion times. IO is significantly shorter. Some people think of an IO as a crutch and it hurts their ego to go straight to it however it is a very viable option. And hopefully people do not overestimate their IV skills and underestimate how quickly an IO really is.

Also, just because the flow rate is better in a PIV does not mean the time to central circulation is better. For fluids its great, medication not so much.


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## DesertMedic66 (Jan 17, 2018)

DrParasite said:


> not even for an opiod OD/cardiac arrest?or a hypoglycemia cardiac arrest?
> 
> I'm curious how an IV (apply tourniquet, find good vein, stick good vein, hope it doesn't clot or collapse on you) takes less time than and IT (put IO needed here, press trigger, make whirrrrrr noise, attach tubing).


This has been covered many many times. Narcan has not been shown to help in cardiac arrests and was removed from ACLS full arrest guidelines (it is included in bystandard/FR CPR because they may lack the training to actually feel a pulse. 

Dextrose admin during a full arrest has been shown to do more harm than good. Once again ACLS removed Hypoglycemia from their list of H’s and T’s several years ago. Dextrose should only be considered in post arrest management/care.


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## CALEMT (Jan 17, 2018)

I remember my preceptor saying when he took a class on IO's a humoral head IO was better that a proximal tibia IO in the case of a full arrest. The reasoning per the instructor of the class is because it's closer to the heart, makes sense but I haven't researched it at all to confirm that is in-fact the case. As for IV vs IO I go for the IO, just because I can establish vascular access faster which in return I can get medications on board faster. 

Personally I don't think there is a difference between IV vs IO. Out of the 8 full arrests I've had one person who I got ROSC on. I don't believe this is because of the fact I started a IO over a IV. I believe its because of outstanding by stander CPR prior to our arrival and early defibrillation. The 7 other arrests were unwitnessed with no CPR PTA.


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## EpiEMS (Jan 17, 2018)

DesertMedic66 said:


> Narcan has not been shown to help in cardiac arrests and was removed from ACLS full arrest guidelines



The 2015 ACLS guidelines say: "We can make no recommendation regarding the administration of naloxone in confirmed opioid-associated cardiac arrest. Patients with opioid-associated cardiac arrest are managed in accordance with standard ACLS practices."

No RCT says that naloxone doesn't help, as far as I know. One small prospective study weakly suggests it may help.

In principle, seems like you're right.



CALEMT said:


> The reasoning per the instructor of the class is because it's closer to the heart,



Why not sternal?


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## Harrison Phord (Jan 19, 2018)

I mean the study does look at around 20 times as many IV patients as IO patients - compounding it, the IO patients generally had non-shockable rhythms, non-cardiac etiologies, and were unwitnessed. So yeah, of course the IV patients are going to have better outcomes looking at that alone.


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## Summit (Jan 19, 2018)

@EpiEMS I hate those sternals... they were a good idea for  battlefield where the patient is on the ground. Trying to get them on a hospital bed?



Creed said:


> I mean the study does look at around 20 times as many IV patients as IO patients - compounding it, the IO patients generally had non-shockable rhythms, non-cardiac etiologies, and were unwitnessed. So yeah, of course the IV patients are going to have better outcomes looking at that alone.



The studies said they had adjusted multivariate analysis... but that doesn't mean the adjustment was sufficient. The fact that parenteral meds intracode (the actual intervention, if not the independent variable, when looking at a dependent variable like ROSC) of are not thought to be effectatious points that this is a selection bias improperly compensated for, or, some other lurking variable problem.


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## FiremanMike (Jan 19, 2018)

I don't personally understand the rationale behind narcan in cardiac arrests.  If we did have a cardiac arrest due to an opiate, it would have been directly caused by the respiratory depression leading to hypoxia, which we have fixed by advanced airway placement and good oxygenation...


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## EpiEMS (Jan 19, 2018)

FiremanMike said:


> I don't personally understand the rationale behind narcan in cardiac arrests.


No disagreement there. These folks briefly list 2 possible mechanisms:

"The interest in the utilization of naloxone in the non-overdosed opioid cardiac arrest patient stems from many hypotheses, one being that endogenous opioids are felt to have a myocardial depressant effect with a lowering of systemic blood pressure. Alternatively, naloxone may stimulate catecholamine release and increase sympathetic nerve activity significantly elevating heart rate and blood pressure."


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## StCEMT (Jan 19, 2018)

The last two people I drilled were unwitnesswd arrests and rather large. IV wouldn't have changed much there.


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## Summit (Jan 19, 2018)

Narcan was gonna be the miracle drug for sepsis, shock, and codes except the studies showed it wasn't... a long time ago.

Hey now we are waiting to see if Marik's ascorbic acid, thiamine, and steroid cocktail is the bees knees for sepsis...


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## EpiEMS (Jan 19, 2018)

Summit said:


> Hey now we are waiting to see if Marik's ascorbic acid, thiamine, and steroid cocktail is the bees knees for sepsis...



Color me skeptical. Without an RCT, we shouldn't jump on this one. (And steroids, eh, doubt they help.)


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## cruiseforever (Jan 19, 2018)

From my experience ROSC pts. get more IVs because of AEDs or first shock conversion from us.  IOs are the first line access for us if one remains in cardiac arrest..


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## Colt45 (Jan 20, 2018)

COmedic17 said:


> Well logically, it makes sense.
> 
> For someone without a pulse, who is receiving cpr, which do you think is going to perfuse better? An EJ which is close to their core? Or a tibial io? When doing good CPR are you more likely to feel a carotid pulse or a pedal pulse?
> 
> In all honesty, I feel most providers assume they won't be able to find a line so they go for the IO. We try IV access before going to the IO and I would say 80% of the time, an EJ or other vascular access ( AC, etc)  is easily obtainable. Have someone push on their liver while someone is doing CPR and they will almost always pop right up. And they don't fight the EJ either, so it's the easiest line ever.




Can you or someone please elaborate a little more on the liver pressure thing? Why would this be more beneficial than a tornoquet on the extremity? It's late at night and this caught my eye. It's a simple anatomy answer but my question is really more why is it going to produce better results than a tornoquet?


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## CALEMT (Jan 20, 2018)

Colt45 said:


> Can you or someone please elaborate a little more on the liver pressure thing? Why would this be more beneficial than a tornoquet on the extremity? It's late at night and this caught my eye. It's a simple anatomy answer but my question is really more why is it going to produce better results than a tornoquet?



Can’t use a TQ when you’re going for an EJ (external jugular). Kinda hard to put a TQ around someone’s neck.


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## DesertMedic66 (Jan 20, 2018)

CALEMT said:


> Can’t use a TQ when you’re going for an EJ (external jugular). Kinda hard to put a TQ around someone’s neck.


It’s not hard to put a TQ around someone’s neck... it’s just generally frowned upon.


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## CALEMT (Jan 20, 2018)

DesertMedic66 said:


> It’s not hard to put a TQ around someone’s neck... it’s just generally frowned upon.



Touché


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## COmedic17 (Jan 20, 2018)

DesertMedic66 said:


> Uhhhh.... narcan and dextrose aren’t cardiac arrest drugs..


You don't give Nathan to known heroin od arrests? 

Or dextrose when they are hypoglycemic? I feel like you probably do.


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## reaper (Jan 20, 2018)

COmedic17 said:


> You don't give Nathan to known heroin od arrests?
> 
> Or dextrose when they are hypoglycemic? I feel like you probably do.


Once you achieve ROSC, then you worry about the dextrose. Giving it during the arrest went out years ago.


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## StCEMT (Jan 20, 2018)

CALEMT said:


> Can’t use a TQ when you’re going for an EJ (external jugular). Kinda hard to put a TQ around someone’s neck.


Secondary use for a stethoscope amigo. Just enough pressure to add a little more size to an EJ


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## Colt45 (Jan 20, 2018)

CALEMT said:


> Can’t use a TQ when you’re going for an EJ (external jugular). Kinda hard to put a TQ around someone’s neck.



Lol I realize that I was referring to an extremity.  I'm pretty sure I even said that in my post.


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## DesertMedic66 (Jan 20, 2018)

COmedic17 said:


> You don't give Nathan to known heroin od arrests?
> 
> Or dextrose when they are hypoglycemic? I feel like you probably do.


Negative on both accounts. Why would I give narcan? What process from a opiate OD kills this patient and what are we already doing during CPR for that issue? Narcan is not going to magically make your cardiac arrest patient start breathing. 

BGL isn’t checked during the codes I run. If I get pulses back then their BGL will be checked and hypoglycemia will be treated from that point on. BGL checks are not accurate during cardiac arrest. 

There is zero evidence that either of those medications are helpful (with evidence of dextrose actually being harmful).

Helpful links, your patients may thank me: https://www.ems1.com/cardiac-care/a...rose-during-cardiac-arrest-improves-outcomes/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4415309/ (Same study as above, just a NCBI link)

http://millhillavecommand.blogspot.com/2012/03/using-dextrose-in-cardiac-arrest.html?m=1

http://roguemedic.com/2015/01/narcan-in-cardiac-arrest-safe-as-long-as-i-dont-understand-safety/


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## VFlutter (Jan 20, 2018)

First of all, I think pressing on someones liver during CPR is a horrible idea. Many patient's body habitus prevents EJ access. And a Humeral IO is pretty much as close to central access as you can get.


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## E tank (Jan 20, 2018)

StCEMT said:


> Secondary use for a stethoscope amigo. Just enough pressure to add a little more size to an EJ




Or you could just put the patient in trendellenburg


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