Prehospital High Flow Oxygen Increases Risk of Death

[RWC130 594]

Prehospital High Flow Oxygen Increases Risk of Death

Nov 20, 2010

By Mike McEvoy

EMS Editor

Prehospital oxygen titrated with pulse oximetry lowered risk of death compared to high flow oxygen in a large Australian study. Researchers randomized 405 patients with difficulty breathing into treatment with high flow oxygen (n=226) and nasal oxygen titrated to maintain oxygen saturations between 88 and 92% (n=179). Titrated oxygen significantly reduced both pre-hospital and in-hospital mortality in all patients by 58%. In patients with confirmed COPD, titrated oxygen reduced risk of death by 78%. Long standing tradition of administering high flow oxygen has been difficult to change, probably due to lack of any clear benefits of titrating oxygen therapy. This relatively large study provides strong evidence that titrated oxygen improves outcomes in prehospital difficulty breathing patients.

Source: Austin MA, et al. Effect of high flow oxygen on mortality in chronic obstructive pulmonary disease patients in prehospital setting: randomised controlled trial. BMJ 2010;341:c5462.

Credit: http://www.fireengineering.com/index/articles/display/9318486270/articles/fire-engineering/fire-ems/house-of-medicine/2010/11/prehospital-o.html

Interesting...

THOUGHTS?

[Alpinerunner 61]

I think the study is accurate, but the title misleading and sensationalistic. High flow oxygen does not increase risk of death. It increases risk of death in patients with confirmed COPD as is mentioned in the body of the article. This is because people with COPD reguate breathing via O2 intake, not CO2 discharge, so giving them high flow O2 will trick their bodies into thinking they are perfusing better than they really are. I'm sure someone with better medical knowledge than I can elaborate or explain it better.

[RNEMT26 40]

What you are referring to is called a Hypoxic drive. Normally we breath because our bodies pick up on the concentration of CO2 in our blood on the arterial side of the system via chemoreceptors located in various, but specific parts of our body. High levels in our PCO2 will cause us to breath faster in order to 'blow off CO2' and low levels in the PCO2 will cause us to breath in deeper and at a slower rate in order to retain CO2 to keep our Ph in between 7.35 - 7.45. The body must maintain this range in order to keep everything working optimally, too high or too low and things can get whacky, esp if it's for a prolonged period of time.

(On a side note, COPDers problems lies in that the are chronically hypoxic, and they are CO2 retainers because their problem isn;t necessarily getting the air in, it's getting the air out, called 'air trapping'. )

A hypoxic drive is when the body has changed over and is now monitoring the PO2 instead of the PCO2. So theoretically if the person reaches 100 % saturation then you've knocked out the stimulus to breath because the body thinks, oh well I'm 100% I guess i dont have to breath. COPDers are as i said, chronically hypoxic, so their drive to breath is because their normal PO2 is low, therefore signals to the body to breath. This hypoxic drive accounts for a low percentage of the population something like 9-10%. Recent studies have no found that COPDers are not soley dependent on this hypoxic drive. So while this may decrease morbidity/mortality, you won't necessarily 'knock out' a COPD PTs resp drive by giving them high flow O2.

One more point, I agree with this research and the titration of O2. Too many people I have found will put a patient on 100% NRBFM because "It's the protocol" Well thats stupid, and dangerous. Not everyone needs 100 O2. If someone is 98-100% if you really feel the need to put them on O2 then put them on 2-4 L N/C. And if it's not even a cardiac or resp related call, and their SpO2 is 100%, then can someone please tell me why it's necessary to place them on 100% NRBFM ? Really? Sorry I'm just an ICU/CCU RN, I clearly don't know what I'm doing..lol

Edited June 28, 2011 by RNEMT26

[16fire5 693]

One more point, I agree with this research and the titration of O2. Too many people I have found will put a patient on 100% NRBFM because "It's the protocol" Well thats stupid, and dangerous.

While the reasearch seems compelling I would caution against bashing people for following the protocol. I think it is more stupid and dangerous if we get people who decide to disregard the protocols based on the latest article they read.

[JohnnyOV 2]

While the reasearch seems compelling I would caution against bashing people for following the protocol. I think it is more stupid and dangerous if we get people who decide to disregard the protocols based on the latest article they read.

While I completely agree, it boggles my mind that there are different standards of care depending on which state, or even which municipality you operate in. Why cant there be a set standard across the board?

[RNEMT26 40]

While the reasearch seems compelling I would caution against bashing people for following the protocol. I think it is more stupid and dangerous if we get people who decide to disregard the protocols based on the latest article they read.

Listen I could sit here and have a pissing match with you on the issues with giving somoeone 100% O2. And just because it's protocol, doesn't necessarily make it the right thing to do at the time for in a particular situation, but we could sit here and talk hypotheticals all day. And people need to always take what they ready with a gain of salt, just because its proven in research does not necessarily make it the best practice.

Edited June 29, 2011 by RNEMT26

[dmc2007 17]

The hypoxic drive theory has been show to be a myth. See:

http://paramedicblog.wordpress.com/2009/11/19/hypoxic-drive-theory-myth-the-why-and-how/

http://respiratorytherapycave.blogspot.com/2008/06/hypoxic-drive-theory-debunked.html

Also, it looks as though the article is trying not to discredit the use of O2 in the field, but rather the use of high flow oxygen, as titrated oxygen (i.e. through a N/C) can be just as, if not more effective, in raising and maintaining oxygen saturation levels in patients with difficulty breathing.

[INIT915 1,119]

The hypoxic drive theory has been show to be a myth. See:

http://paramedicblog.wordpress.com/2009/11/19/hypoxic-drive-theory-myth-the-why-and-how/

http://respiratorytherapycave.blogspot.com/2008/06/hypoxic-drive-theory-debunked.html

Also, it looks as though the article is trying not to discredit the use of O2 in the field, but rather the use of high flow oxygen, as titrated oxygen (i.e. through a N/C) can be just as, if not more effective, in raising and maintaining oxygen saturation levels in patients with difficulty breathing.

Not to get off on a tangent, but I'm not sure I'd say it's "been shown to be a myth" based solely on these two sources. They read more like opinion than research. While, it may actually be that it is not grounded in fact, some legitimate research needs to be done before such a broad ascertain can be made.

[SRS131EMTFF 471]

I discussed this article with my medical control doctor/director up in Vermont back when this article came out and his words were along the lines of "use your best judgement and follow your protocols and let me worry about the rest".

The take away lesson I got was that while this is potentially ground breaking research, it should not get in the way of following protocols that are set in SOP/SOG and you have been trained to use within an existing standard of care.

But then again, I am new to this, I am not a doctor and I may have misunderstood what he really meant.

Edited June 29, 2011 by SRS131EMTFF

[16fire5 693]

Listen I could sit here and have a pissing match with you on the issues with giving somoeone 100% O2. And just because it's protocol, doesn't necessarily make it the right thing to do at the time for in a particular situation, but we could sit here and talk hypotheticals all day. And people need to always take what they ready with a gain of salt, just because its proven in research does not necessarily make it the best practice.

My comments are not in relation to the reasearch. I caution against advising people to disregard the protocol. It's one thing if you are going to do it your self but there may be some impressionable people on here that can apply your advice in a wrong matter. Plus in any event their treatment was quetioned they are much better off having followed the protocol over advice they recieved on a bulletin board. If you feel strongly make your thoughts know to those who make the protocols.

[comical115 32]

Also, it looks as though the article is trying not to discredit the use of O2 in the field, but rather the use of high flow oxygen, as titrated oxygen (i.e. through a N/C) can be just as, if not more effective, in raising and maintaining oxygen saturation levels in patients with difficulty breathing.

If you are running BLS and you don't have pulse oximetry, how can you titrate to effect? If you deviate from your local protocols, *no matter how backwards and/or improper you feel they are*, make sure you have a reason and document properly.

[RNEMT26 40]

My comments are not in relation to the reasearch. I caution against advising people to disregard the protocol. It's one thing if you are going to do it your self but there may be some impressionable people on here that can apply your advice in a wrong matter. Plus in any event their treatment was quetioned they are much better off having followed the protocol over advice they recieved on a bulletin board. If you feel strongly make your thoughts know to those who make the protocols.

I wouldn't say I'm advising people to go against protocol, do what you gotta do. And secondly, if someone was to apply what they read here to real life situation then that's just stupid.

[RNEMT26 40]

The hypoxic drive theory has been show to be a myth. See:

http://paramedicblog.wordpress.com/2009/11/19/hypoxic-drive-theory-myth-the-why-and-how/

http://respiratorytherapycave.blogspot.com/2008/06/hypoxic-drive-theory-debunked.html

Also, it looks as though the article is trying not to discredit the use of O2 in the field, but rather the use of high flow oxygen, as titrated oxygen (i.e. through a N/C) can be just as, if not more effective, in raising and maintaining oxygen saturation levels in patients with difficulty breathing.

The only part of that which is debunked is that giving a COPD PT high flow O2 will cause them to go into Acute Resp. Failure. However, the hypoxic drive is known to exist.

[helicopper 1,050]

The hypoxic drive theory has been show to be a myth. See:

http://paramedicblog...he-why-and-how/

http://respiratorytherapycave.blogspot.com/2008/06/hypoxic-drive-theory-debunked.html

Also, it looks as though the article is trying not to discredit the use of O2 in the field, but rather the use of high flow oxygen, as titrated oxygen (i.e. through a N/C) can be just as, if not more effective, in raising and maintaining oxygen saturation levels in patients with difficulty breathing.

I haven't read the reports on the sites above but caution must be exercised when considering "blogs" as your source of research. Most blogs are not peer-reviewed research-based journals commonly accepted within the medical community.

Before stating that something is a fact or has been shown to be a myth, consider the source.

[helicopper 1,050]

While the reasearch seems compelling I would caution against bashing people for following the protocol. I think it is more stupid and dangerous if we get people who decide to disregard the protocols based on the latest article they read.

You're right, you can't simply go against protocol but if you have findings supporting a deviation from that protocol, a simple phone/radio call to medical control can get you the approval to do it within the scope of your practice and with the protection of your medical control

[antiquefirelt 994]

Oddly enough, when pulse oximetry first hit the field within 6 months special notices were sent out cautioning EMS to not use the technology to ignore signs, symptoms and the related protocols. Now, and very rightfully it would seem, the protocols need to be amended to put more faith in the technology and administering oxygen based on the "proven" need.

I know for a fact that, here, EMS providers have been cited for protocol violations in the past for failing to provide high flow O's to chest pain patients while the oximeter read over 95%. The learning curves need to find their way into protocol, when the other side of the house (admin, legal) continually notes that the best way to limit liability is to strictly follow the approved protocols.

One must be able to be confident that the machine is accurate. This doesn't mean proving by some algorithmic test it works before every shift, but making sure that when it's on the patient it's got a pulse match and the reading makes sense for what you're seeing.

[Goose 188]

Oddly enough, when pulse oximetry first hit the field within 6 months special notices were sent out cautioning EMS to not use the technology to ignore signs, symptoms and the related protocols. Now, and very rightfully it would seem, the protocols need to be amended to put more faith in the technology and administering oxygen based on the "proven" need.

I know for a fact that, here, EMS providers have been cited for protocol violations in the past for failing to provide high flow O's to chest pain patients while the oximeter read over 95%. The learning curves need to find their way into protocol, when the other side of the house (admin, legal) continually notes that the best way to limit liability is to strictly follow the approved protocols.

One must be able to be confident that the machine is accurate. This doesn't mean proving by some algorithmic test it works before every shift, but making sure that when it's on the patient it's got a pulse match and the reading makes sense for what you're seeing.

As far as the hypoxic drive - it does exist, but i spoke to a number of emergency room physicians and all said that a COPD patient would need to be maintained on 12/15 lpm over the course of a number of hours in order to knock out the respiratory drive. That said, i have surely given COPD patients high flow oxygen (NRFM, BVM via ET/OPA, or CPAP) when they need it.

As far as the chest pain you sited - i recall a group discussion at a CME or Audit recently where the physicians (two of them) were starting to lean away from giving every chest pain high flow oxygen. I haven't read much of any literature on it, but it had to do ( at least in part) with free radicals. They were pretty frank in stating that as long as their is no respiratory compromise and that they are showing good clinical signs of perfusion and spo2 is also within normal limits a NC is more than sufficient. In fact, they stated that they 99.9% of the time take off the NRFM and replace it with a NC (i've seen it happen, even in STEMI alerts).

Just thought those two bits were interesting.

Edited June 30, 2011 by Goose

[antiquefirelt 994]

@ Goose: I just had a quick discussion on the topic with our QA Paramedic who noted her impression of the hypoxic drive issue was the longer term administration of high flow oxygen. In the cases regarding chest pain, I'm just wishing that the protocol be updated sooner to reflect current best practices so as proactive EMS personnel are not forced to choose between doing what is thought to be right or what is written in the little book that cover ye arse.

[Goose 188]

@ Goose: I just had a quick discussion on the topic with our QA Paramedic who noted her impression of the hypoxic drive issue was the longer term administration of high flow oxygen. In the cases regarding chest pain, I'm just wishing that the protocol be updated sooner to reflect current best practices so as proactive EMS personnel are not forced to choose between doing what is thought to be right or what is written in the little book that cover ye arse.

Couldn't agree more. Unfortunately (at least here in NY) protocol updates/revisions often have to a lot to do with the willingness/proactivity of physicians. As always some are very proactive in extending flexibility and tools based on best practices to EMS and others, well, not so much.

[antiquefirelt 994]

Couldn't agree more. Unfortunately (at least here in NY) protocol updates/revisions often have to a lot to do with the willingness/proactivity of physicians. As always some are very proactive in extending flexibility and tools based on best practices to EMS and others, well, not so much.

Exactly the same here in Maine. We always feel like by the time the new protocols come out the changes are late and there are a host of new one they should have put in. But, t'is the sign of any good bureaucracy. Thankfully they're modifying our medical control model and it appears that the regional docs will be given more latitude (if they'll accept any perceived or real increased liability) with regard to keeping up with best practices. Or so I'm told, I sit on the periphery of the EMS admin portion of our job.

[dmc2007 17]

I haven't read the reports on the sites above but caution must be exercised when considering "blogs" as your source of research. Most blogs are not peer-reviewed research-based journals commonly accepted within the medical community.

Before stating that something is a fact or has been shown to be a myth, consider the source.

My apologies. Those were some quick links I found. There are many peer-reviewed articles that deal with the matter, the citation to one is below (I've included the abstract as the link through which I'm accessing them are specific to my school and likely won't work for anyone not on our network):

Crossley DJ, McGuire GP, Barrow PM, et al: Influence of inspired oxygen concentration on deadspace, respiratory drive, and PaCO sub 2 in intubated patients with chronic obstructive pulmonary disease. Crit Care Med 1997; 25:1522-1526

Objectives: To investigate the response of CO₂-retaining chronic obstructive pulmonary disease (COPD) patients to an increase in FIO₂ following a period of mechanical ventilation with PaO₂ in the normal range. The administration of a high FIO₂ to chronic obstructive pulmonary disease (COPD) patients may result in hypercapnia. Recent evidence indicates that the hypercapnia may be due to reversal of preexisting regional hypoxic pulmonary vasoconstriction resulting in a greater deadspace. This effect would be more pronounced in patients whose initial PaO₂ was <60 torr (<7.9 kPa)

Conclusion: These results show that following a period of mechanical ventilation with an FIO₂ sufficient to maintain a normal PaO₂, a further increase in FIO₂ does not result in an increased PaCO₂ in this group of CO₂-retaining COPD patients. (Crit Care Med 1997;25:1522-1526)

While it may have been a bit extreme for me to call it a myth, it does seem that the sentiment that giving O2 to a COPD patient will result in sudden respiratory arrest is unfounded, and that the effects of the hypoxic drive won't be seen pre-hospitally. This is what I was getting at in my initial post.

[NWFDMedic 58]

Protocols rarely change based on one study, even if it is well conducted and peer reviewed. Even when they do, it's not always the best thing. Remember when the AHA knocked lidocaine down significantly in the ventricular dysrhythmia protocol based on the lack of evidence that lidocaine worked. We all knew that lidocaine worked but nobody was going to pay for a test on a cheap drug.

While 100% oxygen via NRB-FM may not result in serious respiratory issues for COPD patients in the length of an ambulance ride, I've often heard doctors relate that correcting the excessive PO2 complicates a patient's treatment and return to normal. Getting the patient to the hospital is a great goal to have and yes, most patients will not suffer ill effects due to high flow oxygen during that time. However, we should be striving to fit our care into a total care plan for the patient that allows them to have the best outcome.

[ny10570 745]

The study that started this thread is not concerned with causing repsiratory failure from the administration of high flow O2. The increased mortality is associated with hypercapnia and acidosis. The average patient was under EMS care for 45 minutes. I'm pretty sure Westchester's numbers are pretty close to that.

[ckroll 101]

Wow, the stuff I miss when I go on vacation. First, the best way to avoid liability is to provide good care. Second, per BLS protocols..."Since patients do not always fit into a "cook book" approach, these protocols are not a substitute for GOOD CLINICAL JUDGMENT". Third, ACLS 2010 is clear on the subject. O2 sat of 94% and above does not need supplemental oxygen in most situations.

Fourth, with COPD patients, a significant issue is pH. Hypoxic drive is secondary. the individual is borderline in terms of pH and the body is doing all it can to buffer. One buffering mechanism is in the red blood cell, which can hang onto 6 CO2 molecules. Heme groups preferentially bond to O2. If you have many of the heme groups loaded with CO2 and provide 100% O2, the body will dump CO2 to the blood stream to pick up O2 and in the process spike the pH down. Significant research in credited journals identify the pH spike as an important part of the pathophysiology. I'll look it up and post same.

[MoFire390 118]

so im gonna guess this report pretty much says CPAP is useless??? please if someone can clarify for me...kinda thought CPAP could help someone with COPD.

[ny10570 745]

Report said nothing about CPAP. Oxygen powered systems are only going to deliver 100% O2, but hospital based electric systems can meter out a desired O2 concentration.

[ckroll 101]

so im gonna guess this report pretty much says CPAP is useless??? please if someone can clarify for me...kinda thought CPAP could help someone with COPD.

It's a good topic to discuss. First, why do you think that CPAP could help someone with COPD? Can you describe the mechanism?

[ny10570 745]

I'm seeing BiPAP used more and more for COPD in the ERs. It surprised me as I figured air trapping plus increased airway pressure would equal barotrauma, but the real benefit is with acute exacerbation and providing support for tired veintilatory muscles.

[RNEMT26 40]

please if someone can clarify for me...kinda thought CPAP could help someone with COPD.

It depends on the situation. Im not sure of how much you know about BiPAP/CPAP but it has obviously 2 settings a IPAP (inspiratory) and an EPAP (expiratory). Usually we set it @ 10/5 with most patients and tweak it as necessary. The EPAP is lower and is supposed to help with exhalation. CPAP it just what it says Continuous Positive Airway PRessure, so a COPDers have a problem with air trapping, so it's getting their out not, not necessairly getting it in.

Now if it's somone who is in resp. failure then chances are this person is gonna get intubated at some point, which in all honesty is sometimes the best thing for them. We usually rest their lungs for 2-3 days and then wake them up and pull that tube. If the situation is more in the CHF realm then you can us BiPAP or CPAP with diuretics and nitrates (sometimes) to help clear their lungs up.

Edited July 17, 2011 by RNEMT26

[ckroll 101]

Medscape has an excellent article on the same topic that I believe references the same work. [Jan, 2011]

Chronic Obstructive Pulmonary Disease and Emphysema in Emergency Medicine

http://emedicine.medscape.com/article/807143-overview#a0104

Among other things, it serves to remind us that COPD is a basket of comorbidities. Do knowlegable people out there have experience with CPAP/BiPAP with respect to bronchitis vs emphysema?

At present, HVREMAC allows for CPAP in COPD, but WREMAC does not. Obviously different physicians have different opinions as to the value of CPAP for COPDers. Is it perhaps more effective with one type of COPD?

I also think a take home message is that before intubating the conscious patient, or letting that patient deteriorate that CPAP is worth a try. Worst case, we take it off, correct?