When will O2 truly help?

[chbare]

I suppose the theoretical answer is that if a patient is hypoxic without being hypoxemic, their O2 sat will not reveal their true level of cellular distress.

It's not even theoretical. This is the basis of a concept known as histotoxic hypoxia and explains conditions such as cyanide toxicity. This is typically because of the inhibition of the membrane bound protein cytochrome c oxidase.

Take care,

chbare.

[LifeguardsForLife]

This is awesome and informative, guys, but I'm still interested mainly in the original question. I guess we've all agreed that there can be a strong placebo effect attached to any use of O2; that said, there will still be cases where it's also physiologically beneficial, and those where it's not.

My treatment for anemia is a bolus of definitive care

Oxygen is inexpensive, easily obtainable, ad widely utilized as to impede and prevent the effects of hypoxia. Since it's discovery in the late 1700's oxygen has remained one of the most effective therapeutic agents known to the medical world. However, currnent literature suggests this medication is all too commonly administered at extremely high doses, causing hyperoxia. But oxygen is harmless right? Hyperoxia induces bradycardia and a reduction in cardiac output, which partly offsets the otherwise increased oxygen delivery. below are several different articles or studies regarding potentila risks of high flow oxygen.

A publication in the October 2003 issue of Chest confirm that 100% oxygen can be harmful for asthmatics and support recommendations to use the minimum concentration required to maintain target O2 saturation.

. Results: The administration of 100% oxygen significantly increases Paco₂ (p = 0.03) and decreases PEFR (p = 0.001) as compared with administration of 28% oxygen. Paco₂ before and during oxygen administration correlated significantly (p = 0.001) in both groups. Patients breathing 28% oxygen experienced a Paco₂ fall; on the contrary, patients who received 100% oxygen showed an increase in Paco₂, particularly those with Paco₂ before oxygen treatment > 40 mm Hg.

Retinopathy of prematurity

ROP, first identified in 1942, occurs in about 3,500 premature infants each year in the United States. Estimates are that between 350 and 500 infants each year are blinded because of the condition. The remaining infants can suffer some long-lasting visual problems.

The problem occurs when an infant is given supplemental oxygen at birth to aid his or her underdeveloped lungs. At that time, the blood vessels in the child¹s retinas are still developing, and oxygen therapy can cause these blood vessels to grow abnormally. After the abnormal growth begins, vessels that are supposed to remain with the retina of the eye can actually grow into the center of the eye, causing retinal detachment. The only way to repair the problem is with invasive laser therapy, which can cause damage to healthy retinal tissue.

Dr. Bledsoe on "the oxygen myth"

Stroke: The brain is very vulnerable to the effects of oxidative stress. The brain has fewer antioxidants than other tissues. Thus, should we give oxygen to non-hypoxic stroke patients? Studies have shown that patients with mild-moderate strokes have improved mortality when they receive room air instead of high-concentration oxygen.

The data on patients with severe strokes is less clear.(5) Current research indicates that supplemental oxygen should not be routinely given to patients with stroke and can, in some cases, be detrimental.(6)

Acute Coronary Syndrome: The myocardium is highly oxygen dependent and vulnerable to the effects of oxidative stress. Thus far, there's no evidence that giving supplemental oxygen to acute coronary syndrome patients is helpful, but there's no evidence it's harmful.(7)

Post-Cardiac Arrest: Here, too, the evidence is too scant to tell. We do know that virtually all current therapies for cardiac arrest (drugs, airway) are of little, if any, benefit. The primary therapies remain CPR (often with limited ventilation initially) and defibrillation followed by induced hypothermia. The whole purpose of induced hypothermia is to prevent the detrimental effects of oxidative stress and the other harmful effects of reperfusion injury.

Trauma: What role should oxygen play in non-hypoxic trauma patients? Little research exists, but an interesting study out of New Orleans demonstrated that there was no survival benefit to the use of supplemental oxygen in the prehospital setting in traumatized patients who do not require mechanical ventilation or airway protection.(8)

Carbon Monoxide (CO) Poisoning: We have learned a lot about carbon monoxide poisoning in the past few years. We know that the mechanism of CO poisoning is a lot more complex than once thought. We also know that there's no reliable evidence that hyperbaric oxygen (HBO) therapy improves outcome (although it's still widely used).(9) But when you think about it, the goal of treatment in CO poisoning is to eliminate CO through ventilation -- not hyperoxygenation. Although oxygen can displace some CO from hemoglobin, the induction of free-radicals may be worse than the effects of CO. Again, the science here is in a state of flux.

Neonates: The science is clear in regard to supplemental oxygen in neonates. It should be used only when room air ventilation fails.

Again, this is a discussion of the changing science. Always continue to follow the direction of your medical director and local protocols. That said, it's clear that we need to use every tool possible to support, but not replace, our physical exam skills. We should use pulse oximetry and waveform capnography. Although, individually, each technology has its limitations, together they provide important information about the patient.

-http://www.jems.com/news_and_articles/columns/Bledsoe/the_oxygen_myth.html

oh and, apparently concentrated oxygen is ineffective at harming or killing cancer cells(an interesting read) -http://www.cancer.org/docroot/eto/content/eto_5_3x_oxygen_therapy.asp

hope this provides some insight for you.

[VentMedic]

Neonates: The science is clear in regard to supplemental oxygen in neonates. It should be used only when room air ventilation fails.

Bledsoe did provide some misleading information in that article.

From the AAP and the 2005 NRP guidelines which were in effect when he published that articls:

For babies born at term,

• The Guidelines recommend use of

100% supplemental oxygen when

a baby is cyanotic or when positive pressure

ventilation is required

during neonatal resuscitation.

• However, research suggests that

resuscitation with something less than

100% may be just as successful.

It does not say room air. Some do start at 40%, 50% or 60% but not room air.

• If resuscitation is started with less than

100% oxygen, supplemental oxygen

up to 100% should be administered if

there is no appreciable improvement

within 90 seconds following birth.

You do not wait for "failure".

• If supplemental oxygen is

unavailable, use room air to deliver

positive-pressure ventilation.

A publication in the October 2003 issue of Chest confirm that 100% oxygen can be harmful for asthmatics and support recommendations to use the minimum concentration required to maintain target O2 saturation.

Results: The administration of 100% oxygen significantly increases Paco2 (p = 0.03) and decreases PEFR (p = 0.001) as compared with administration of 28% oxygen. Paco2 before and during oxygen administration correlated significantly (p = 0.001) in both groups. Patients breathing 28% oxygen experienced a Paco2 fall; on the contrary, patients who received 100% oxygen showed an increase in Paco2, particularly those with Paco2 before oxygen treatment > 40 mm Hg.

This article did more to explain the death of the hypoxic drive theory by way of the release of hypoxic pulmonary vasoconstriction and ventilation/perfusion mismatching.

http://chestjournal.chestpubs.org/content/124/4/1312.full'>http://chestjournal.chestpubs.org/content/124/4/1312.full

From the article (if this is the article you referenced):

Hyperoxia associated with hypercarbia occurring in asthma exacerbations, and especially without any evidence of respiratory suppression, would be more easily explained by the regional release of hypoxic pulmonary vasoconstriction. This factor had a major role in determining V̇/Q̇ matching, as V̇/Q̇ inequality worsened considerably after administration of 100% oxygen. This has been shown in patients with acute asthma receiving ventilation and not receiving ventilation22 23 ; therefore, patients with most severe baseline condition probably have more hypoxic vasoconstriction, and they had the greatest increase in Paco2 while breathing 100% oxygen.

But then for asthma, oxygenation is generally not the issue but rather ventilation which is why 80/20 and 70/30 HeliOx mixtures are used. However, when 21% or 100% O2 can not be ventilated for gas exchange and no heliox is available, you use what you have available to maintain SpO2 even if that means 100% oxygen.

For all the other situations, there are variables in each situation that must be examined. No blanket statment should be made for any one situation at there are some situations where 100% O2 will be necessary. Prehospital just hasn't gotten so far as to running SvO2 or StO2 monitoring on everyone to see the tissue oxygenation. Also, many of the studies were done on long term effects and not for the 15 minutes an EMT(P) are with a patient. Right now StO2 monitoring is becoming more populat if SvO2 is not immediately available although one can be obtained by iSTAT or other POC as soon as central venous access is available. Thus, the patient is then treated by that rather than the SpO2 or SaO2. If the patient is septic, there are also guidelines and protocols in place for 100% O2 to be initiated. Pulmonary HTN is also an issue after a traumatic event as is ARDS and both may require 100% O2 until the patient can be placed on the proper gases, ventilator and medicine. The same is true for PPHN of the neonate.

Right now, O2 is used with caution and maybe not at all or even subambient for ductal dependent cyanotic heart lesions. For others, research is still being done in a very controlled environment.

However, I think it is great that you are reading the journals. The further you advance in college, the more all of this will start to make sense. But, in medicine there are very few concrete answers which makes it an exciting field to be in. Just when we think we've got all our guidelines and protocols working smoothly the patient decides to toss us another issue just to see if we're paying attention. It is those who take everything in their protocols as "the word" and fail to look at the whole picture that miss what the patient's body is trying to tell you. When reading an article, look at the whole study to see similarities and differences. They may be focused on proving just their one theory when they have actually supported something else. Thus, that leads to another research article to be written.

CEHST is a great journal for those who want to know what is happening in the world of Cardiopulmonary Science:

http://chestjournal.chestpubs.org/

The Journal of Respiratory and Critical Care Medicine is also a great journal.

http://ajrccm.atsjournals.org/

For prehospital:

Prehospital Emergency Carehttp://www.informaworld.com/smpp/title~content=t713698281~db=all

Resuscitation Journal also has some great articles from an international perspective.

http://www.elsevier.com/wps/find/journaldescription.cws_home/505959/description#description

For those interested in neonates and pediatrics:

AAP

http://www.aap.org/

NRP

http://www.aap.org/nrp/nrpmain.html

Johns Hopkins Neonatal Newsletter

http://www.eneonatalreview.com/

Journal of Pediatrics

http://www.jpeds.com/

Annals of Pediatric Cardiology

http://www.annalspc.com/

Also, after reading the many articles in the various journals, one can easily see why "scenarios" are not always as simple as they appear. You may have treated an obvious symptom but have not actually diagnosed the cause but rather assessed for a working diagnosis to run the protocols you have available. The more knowledge you acquire, the more protocols or guidelines you may have to go with your assessments when working in different areas as a Paramedic such as Flight, CCT or Specialty transport.

Keep researching the journals. They'll open you eyes even more to the vast information out there and hopefully inspire you to take your career to a higher level regardless of what title you work under.

I almost forgot to reference the Canadians. They've been known to do some fine medical research also.

Canadian Respiratory Journal

http://www.pulsus.com/journals/journalHome.jsp?HCtype=Consumer&jnlKy=4&/home2.htm&

Edited December 27, 2009 by VentMedic

[Jwade]

Bledsoe did provide some misleading information in that article.

From the AAP and the 2005 NRP guidelines which were in effect when he published that articls:

For babies born at term,

• The Guidelines recommend use of

100% supplemental oxygen when

a baby is cyanotic or when positive pressure

ventilation is required

during neonatal resuscitation.

• However, research suggests that

resuscitation with something less than

100% may be just as successful.

It does not say room air. Some do start at 40%, 50% or 60% but not room air.

• If resuscitation is started with less than

100% oxygen, supplemental oxygen

up to 100% should be administered if

there is no appreciable improvement

within 90 seconds following birth.

You do not wait for "failure".

• If supplemental oxygen is

unavailable, use room air to deliver

positive-pressure ventilation.

This article did more to explain the death of the hypoxic drive theory by way of the release of hypoxic pulmonary vasoconstriction and ventilation/perfusion mismatching.

http://chestjournal.chestpubs.org/content/124/4/1312.full'>http://chestjournal.chestpubs.org/content/124/4/1312.full

From the article (if this is the article you referenced):

But then for asthma, oxygenation is generally not the issue but rather ventilation which is why 80/20 and 70/30 HeliOx mixtures are used. However, when 21% or 100% O2 can not be ventilated for gas exchange and no heliox is available, you use what you have available to maintain SpO2 even if that means 100% oxygen.

For all the other situations, there are variables in each situation that must be examined. No blanket statment should be made for any one situation at there are some situations where 100% O2 will be necessary. Prehospital just hasn't gotten so far as to running SvO2 or StO2 monitoring on everyone to see the tissue oxygenation. Also, many of the studies were done on long term effects and not for the 15 minutes an EMT(P) are with a patient. Right now StO2 monitoring is becoming more populat if SvO2 is not immediately available although one can be obtained by iSTAT or other POC as soon as central venous access is available. Thus, the patient is then treated by that rather than the SpO2 or SaO2. If the patient is septic, there are also guidelines and protocols in place for 100% O2 to be initiated. Pulmonary HTN is also an issue after a traumatic event as is ARDS and both may require 100% O2 until the patient can be placed on the proper gases, ventilator and medicine. The same is true for PPHN of the neonate.

Right now, O2 is used with caution and maybe not at all or even subambient for ductal dependent cyanotic heart lesions. For others, research is still being done in a very controlled environment.

However, I think it is great that you are reading the journals. The further you advance in college, the more all of this will start to make sense. But, in medicine there are very few concrete answers which makes it an exciting field to be in. Just when we think we've got all our guidelines and protocols working smoothly the patient decides to toss us another issue just to see if we're paying attention. It is those who take everything in their protocols as "the word" and fail to look at the whole picture that miss what the patient's body is trying to tell you. When reading an article, look at the whole study to see similarities and differences. They may be focused on proving just their one theory when they have actually supported something else. Thus, that leads to another research article to be written.

CEHST is a great journal for those who want to know what is happening in the world of Cardiopulmonary Science:

http://chestjournal.chestpubs.org/

The Journal of Respiratory and Critical Care Medicine is also a great journal.

http://ajrccm.atsjournals.org/

For prehospital:

Prehospital Emergency Carehttp://www.informaworld.com/smpp/title~content=t713698281~db=all

Resuscitation Journal also has some great articles from an international perspective.

http://www.elsevier.com/wps/find/journaldescription.cws_home/505959/description#description

For those interested in neonates and pediatrics:

AAP

http://www.aap.org/

NRP

http://www.aap.org/nrp/nrpmain.html

Johns Hopkins Neonatal Newsletter

http://www.eneonatalreview.com/

Journal of Pediatrics

http://www.jpeds.com/

Annals of Pediatric Cardiology

http://www.annalspc.com/

Also, after reading the many articles in the various journals, one can easily see why "scenarios" are not always as simple as they appear. You may have treated an obvious symptom but have not actually diagnosed the cause but rather assessed for a working diagnosis to run the protocols you have available. The more knowledge you acquire, the more protocols or guidelines you may have to go with your assessments when working in different areas as a Paramedic such as Flight, CCT or Specialty transport.

Keep researching the journals. They'll open you eyes even more to the vast information out there and hopefully inspire you to take your career to a higher level regardless of what title you work under.

I almost forgot to reference the Canadians. They've been known to do some fine medical research also.

Canadian Respiratory Journal

http://www.pulsus.com/journals/journalHome.jsp?HCtype=Consumer&jnlKy=4&/home2.htm&

VENT,

Great Reply and Good Info,

However, Speaking of " Blanket Statements" as you so elegantly stated, I do believe the above highlighted portion is indeed a blanket statement and a very big assumption on your part?

JW

[VentMedic]

VENT,

Great Reply and Good Info,

However, Speaking of " Blanket Statements" as you so elegantly stated, I do believe the above highlighted portion is indeed a blanket statement and a very big assumption on your part?

JW

The whole sentence is:

Also, many of the studies were done on long term effects and not for the 15 minutes an EMT(P) are with a patient.

It is rare that a Paramedic will spend many hours with a patient and if they do they will or should have advanced protocols/equipment to deal with those situations. For Specialty, Flight and CCCT we will have several pressors, advanced ventilators, Nitric Oxide, Flolan or something similar and in some areas heliox might be available although the tank will not last very long. Each of these therapies may enable us to reduce the FiO2 as the situation allows. Again, a few situations will require us to remain at an FiO2 of 1.0.

However, thanks for the compliment on my post.

I remember back 2 -3 years ago when you and I used to have indepth conversations on another forum about these topics.

Edited December 27, 2009 by VentMedic

[HellsBells]

Just spoke to my wife, Board Certified MD ( Anesthesia). You have to fix the underlying hematocrit issue first and foremost.....You can start splitting hairs like some of the posters above have started doing, however, real world application is going to do very little to help anyone...

There is no doubt the underlying issue needs to be fixed. The same can be said for almost any pt we transport with oxygen; 02 is not going to fix the underlying problem in an MI, GI bleed, or hypovolemic trauma pt either. Yet, it is still good practice to provide oxygen to these pts

[Jwade]

The whole sentence is:

Also, many of the studies were done on long term effects and not for the 15 minutes an EMT(P) are with a patient.

It is rare that a Paramedic will spend many hours with a patient and if they do they will or should have advanced protocols/equipment to deal with those situations. For Specialty, Flight and CCCT we will have several pressors, advanced ventilators, Nitric Oxide, Flolan or something similar and in some areas heliox might be available although the tank will not last very long. Each of these therapies may enable us to reduce the FiO2 as the situation allows. Again, a few situations will require us to remain at an FiO2 of 1.0.

However, thanks for the compliment on my post.

I remember back 2 -3 years ago when you and I used to have indepth conversations on another forum about these topics.

Vent,

I was not insinuating that a paramedic will spend hours with a patient, just merely pointing out that including " 15 min" in your entire statement seems a bit presumptuous. Just saying.....

Yes, I remember those conversations very well, I am hoping to get enough time back in my schedule soon to start having those in depth discussions once again. I have just a couple classes left for my MHA, and then I am DONE with school! :-)

I really do enjoy reading your posts, always very educational and well written. I just always like to play devil's advocate when needed ;-)

Hope your well, and Happy Holidays!

JW

There is no doubt the underlying issue needs to be fixed. The same can be said for almost any pt we transport with oxygen; 02 is not going to fix the underlying problem in an MI, GI bleed, or hypovolemic trauma pt either. Yet, it is still good practice to provide oxygen to these pts

Hells,

Agreed, and I never stated I would NOT give O2, I was simply trying to get people to think about the " WHY " you do things in practice.....I see so many people who can only do If A, Do B, and have NO clue about why!

Respectfully,

JW

[AnthonyM83]

As far as the experience portion:

It seems to work well on near syncope, positive orthostatic, weak/dizzy patients very well (depending on cause, of course). That's patient experience.

For personal experience, I woke up from a shift extremely sick once, was dehydrated, and had sudden sweating, skin felt cool, (I'm sure I was pale), and head not quite hurt, but felt like worst hang over ever. I literally crawled to an O2 tank in supply room and received very quick relief from an NRB. It felt like life coming out of that thing. Felt so good to take those deep breaths of O2. After the episode itself passed I was fine.

[Chief1C]

Maybe off topic, but not really. Going back 30 years, to the popular EMS-related series, Emergency!. You never seen them give oxygen, unless the victim was in need of resuscitation. It was very rare to see oxygen being given, as "supplemental" oxygen. I thought of this from an episode in Season 6, where they're on vacation, in a private ambulance. One victim has head injuries, the other, internal bleeding. The only visible equipment, are two "E" cylinders w/ regulators directly beside them. That just crossed my mind when I seen recent comments on this thread.

[VentMedic]

Even in the early 70s oxgygen equipment was not well suited for transport. There were no D tanks and the ones they had were heavy and bulky. Oxygen tents were still a popular means of delivering O2 in the hospitals. BVMs were still fairly primitive and not very practical for resuscitation. Modern CPR was still being improved upon. Not a lot of disposable equipment. The old Emerson resuscitator (later replaced by the Elder demand valve) was a bulky gas hog.

Then when you added on the size of the defibrillator and the MAST to a stretcher that waa no were near what we have today, nor the stair chairs, it is a wonder we didn't just make the patient run along side while the equipment was on the stretcher.

On one of my early pedi IFT transports around 1980, the RN and RT had the child strapped to an adult back board with an early verson of the Servo ventilator attached which was the closest thing we had to portable even then that could be easily adjusted. The Birds were also portable but bulky and gas hogs.

Pulse oximetry (as well as ABG analysis) was also still in its infancy in the 70s and believe it or not if the patient didn't just get 100% O2, we actually had to assess the patient's color, HR, perfusion and breath sounds to adjust the O2. Actually some of the earlier devices had just one Venturi adjustment with either 100% or somewhere around 40 or 50%.

CPAP has been around for since the mid 1900s and even in home care for a couple of decades before EMS saw it.

Ambulance services were also not well regulated in the 1970s and California was of course having each county do its own thing.

Edited December 30, 2009 by VentMedic