Too Much Oxygen? hmmmm

[HeadNurseRN]

I was in a nursing home once and this nurse was talking to another nurse about this lady who was hooked up to a oxygen concentrator via nasal cannula. This lady was alittle loopy but since she was old I figured her brain was fried. Long story short the nurse went on to say she was alittle crazy because theres so much oxygen going to her brain she was losing it. I looked at myself and always thought 02, Oxygen was like chicken noodle soup was when your sick. How can you get enough 02 into you? I know some what about people being oxygen dependency but still. When I became a nurse even I don't know everything. Once you know everything in this field hang up your scrubs and stethoscope.

 

[MrBrown]

Not sure about the specific context in which you refer however there is such a thing as hyperoxemia ie too much oxygen.

Hence why this crazy concept of shoving 15 litres of oxygen down everybodies throat is a bad thing.

 

[jjesusfreak01]

Not sure about the specific context in which you refer however there is such a thing as hyperoxemia ie too much oxygen.

Hence why this crazy concept of shoving 15 litres of oxygen down everybodies throat is a bad thing.

New Wake County rule, effective immediately:

Pts in respiratory distress (even STEMIs) are titrated to between 94 and 99 percent. If they sat above 94% on room air, they need no supplemental O2. We no longer aim for 100%, because then you don't know what their true sat is.

 

[Jon]

I've been getting some dirty looks lately from BLS providers for withholding O2 from a patient when they have an adequate O2 sat.

 

[JPINFV]

Naw... at SpO2 of 100, you know their true sat. What you don't know is how much oxygen is actually required to reach that. Once at 100% with 15 L/m you don't know if 4, 6, 10, 12, or any other level below 15 is necessary to maintain an appropriate saturation.

 

[JJR512]

Not sure about the specific context in which you refer however there is such a thing as hyperoxemia ie too much oxygen.

Hence why this crazy concept of shoving 15 litres of oxygen down everybodies throat is a bad thing.

Depending on which dictionary one uses, hyperoxemia can mean either an excessive amount of oxygen or acidity in the blood.

http://dictionary.reference.com/browse/hyperoxemia
http://medical-dictionary.thefreedictionary.com/hyperoxemia

An excessive amount of oxygen in blood (and tissues and organs) is better known as hyperoxia. Just like hypoxia but with the hyp- replaced with hyper-.

http://dictionary.reference.com/browse/hyperoxia
http://medical-dictionary.thefreedictionary.com/hyperoxia

What's more important (and relevant) is the condition known as oxygen toxicity.

http://en.wikipedia.org/wiki/Oxygen_toxicity

Here is an older related thread here: [thread=2703]http://www.emtlife.com/showthread.php?t=2703[/thread]

 

[Shishkabob]

To be fair, even with a 100% O2 sat, you can still hold more oxygen.



I was once called to a surgery facility for a patient with, and I quote, "Elevated O2 sats".

I asked dispatch to clarify that they were elevated, and the dispatcher repeated it.


I said "Roger, show us responding to a patient breathing normally."

 

[MMiz]

New Wake County rule, effective immediately:

Pts in respiratory distress (even STEMIs) are titrated to between 94 and 99 percent. If they sat above 94% on room air, they need no supplemental O2. We no longer aim for 100%, because then you don't know what their true sat is.

What happens when the O2 sat reading is incorrect? I'd sure hate to be the guy that withheld oxygen from a patient in need.

 

[jrm818]

You can hold more oxygen, but really it is not that much. The oxygen content of the blood is: 1.34 x Hb x (SaO2/100)] + 0.003 x PO2

Thus someone with a PO2 of 200mmHG may only have 0.33mlO2/100ml more than someone with a PO2 of 100mmHG.


Don't underestimate the patient with excessive O2 sat's. The cosmic wormhole opened by having 110% of your hemoglobin oxygenated can be quite problematic.

 

[Shishkabob]

Meh, depends.


Say you're about to perform RSI. Washing out the nitrogen reserves and getting every little bit of O2 in there, from the alveoli to hemoglobin saturation to plasma saturation is wanted. More O2 = more time for apnea without fear.


(Apnea and 'without fear' in the same sentence?!)

 

[jrm818]

What happens when the O2 sat reading is incorrect? I'd sure hate to be the guy that withheld oxygen from a patient in need.

That possible baddness has to be balanced against the demonstrated baddness that occurs when you over-oxygenate patients with COPD, or ACS, and there soon may be convincing evidence of baddness in cardiac arrest and maybe some other settings.

So it comes down to weighing the chance of an error with the chance of error with too much oxygen. I acutally don't know if there is any good literature on the reliability of pulse oximiters. Anyone know?

 

[jrm818]

I'll agree with "depends." The one time oversaturaiton prior to RSI is different than a constant oversaturation in ACS or COPD. Different goals, different time courses, etc.

 

[JPINFV]

To be fair, even with a 100% O2 sat, you can still hold more oxygen.

True, but at what cost?

 

[JPINFV]

Meh, depends.


Say you're about to perform RSI. Washing out the nitrogen reserves and getting every little bit of O2 in there, from the alveoli to hemoglobin saturation to plasma saturation is wanted. More O2 = more time for apnea without fear.


(Apnea and 'without fear' in the same sentence?!)

http://connect.jems.com/forum/topics/using-a-nasal-cannula-at-15

Pertinent to this comment.

 

[JPINFV]

What happens when the O2 sat reading is incorrect? I'd sure hate to be the guy that withheld oxygen from a patient in need.

What happened to correlating the SpO2 to the patient's presentation?

What happened to correlating the pulse reading on the pulse ox with a manually measured pulse?

In monitors that display the wave form, what happened to looking at the wave form to ensure that the wave form is appropriate (not topping out of bottoming off)?

Why not give naloxone to every patient with ALOC just in case?

Why not give D50 (or D10) to every patient in case the glucometer is broken?

What if the filter on the 12 lead is accidentally filtering out a STEMI?

I'd hate to be the guy who deprived the hypoglycemic patient IV dextrose, but I need something more, nay, anything other than paranoia to distrust a glucometer.

I'd hate to be the guy who delays a STEMI activation because the 12 lead was broken, but I need something more than paranoia, nay, anything other than paranoia to distrust the EKG.

Is there any evidence that a properly applied pulse oximeter with a good wave form and/or a pulse reading that matches a manually measured pulse or a cardiac monitor should not be trusted just in case?

 

[MMiz]

JPINFV,

I found the pulse oximeters I used in the field were horribly unreliable. jj's post:

Pts in respiratory distress (even STEMIs) are titrated to between 94 and 99 percent. If they sat above 94% on room air, they need no supplemental O2.

Seems like a pretty crazy protocol. I'd think that skin perfusion, patient appearance, and complaint would provide some leeway.

 

[JPINFV]

Just curious, unreliable based on attempting to correlate to patient presentation? ABG? Hospital pulse ox reading at ED?

 

[Journey]

JV,

I found the pulse oximeters I used in the field were horribly unreliable. jj's post:

Seems like a pretty crazy protocol. I'd think that skin perfusion, patient appearance, and complaint would provide some leeway.

Valid point.

Some forget about the basic factors of what shifts the oxyhemoglobin curve. They assume that all people with an SpO2 of 96% will have the same PaO2. Some also forget get about tissue oxygenation and why we have Svo2 and StO2 monitors.

It is also quite possible for a dying/dead patient to have a high SpO2 value. This is the case when peripheral oxygen consumption is quite low,
resulting in an increased mixed venous saturation. If extraction is very low and the patient is still receiving oxygen therapy, it is easily possible for the patient to have a high SpO2 value.

The pulse oximeter provides a very useful number but unless you have an understanding of how it is derived and the factors that influence it including many of the complex medical or cardiac situations, it is just a number to write down in the vital signs section of your report. It may not be the inaccuracy of the pulse oximeter as much as it is the inability of the user to determine how that number relates to the patient.

 

[Anjel]

Treat your patient not the machine.

I dont care if the pulse ox tells me its 1000 percent. If my patient is having a hard time breathing or showing cyanosis anywhere. They shall be getting o2 from me.

Side note: Besides being cold, poor circulation, and co2 poisoning. Does Shock cause an inaccurate reading? Or does that go along with poor circulation.

 

[JPINFV]

It is also quite possible for a dying/dead patient to have a high SpO2 value. This is the case when peripheral oxygen consumption is quite low,
resulting in an increased mixed venous saturation. If extraction is very low and the patient is still receiving oxygen therapy, it is easily possible for the patient to have a high SpO2 value.

...and, giving the topic of this thread and oxygen administration, you can make an argument that the near dead who have a good O2 saturation with no dyspnea need supplemental oxygen? The indication for supplemental oxygen is not "sick patient." A patient can be sick, even terminally, and not need supplemental oxygen.