O2 Sats..bad if 100%..?

locolorenzo22, BSN, RN · Apr 10, 2008

maybe to decrease o2 sats you should do one of the following:

-go back to clinicals and forget all your drug info....

-get up and run around

-engage in some "extra" activities.

-or punch the good doctor in the face a few times......

any other thoughts?

GilaRRT · Apr 10, 2008

DaMale Nurse: Good thinking. Allow me to expand on the Bohr Effect? The Bohr effect is the primary mechanism which prompts the movement of oxygen from the RBC into the body tissue. The Bohr effect is associated with a right shift on the curve. In addition, the reverse should occur in the lungs. When CO2 binds to HBG, a change in the shape of the HBG occurs and the HBG will give up or release O2. In the lungs, CO2 leaves the HBG and the HBG changes shape allowing for the movement of oxygen into the RBC.

In addition, we need to remember the difference between pulse oximetry and PO2. Pulse oximetry measures that amount of HBG that is bound by oxygen. (In most cases.) The measurement is indirect and a multitude of factors can effect the reading. PO2 is the measurement of the pressure of oxygen dissolved in our plasma. So, remember, saturation and PO2 readings while related, are not the same thing. Any time you shift the curve, you will alter the relationship of partial pressure to HGB saturation.

I remember it like this:

Right shift= Release O2: Raised acids, Raised temp, Raised 2-3 DPG, Reduced oxygen.

Left shift= Lock O2 (or hoLd O2): Low 2-3 DPG, Low temp, aLkaLosis (Low acids), Lot of CO.

Useless knowledge for the day: One of the most common situations where we see altered levels of 2-3 DPG is with massive blood transfusions. You will decrease 2-3 DPG levels and cause a Left Shift with massive blood transfusions. What does this mean? Well, the blood holds on to O2 like a big dog, but it may not release O2 to the tissue that badly needs the O2.

High saturation, but the patient is still in trouble.

Finally, I would hope people would look at the entire clinical picture when attempting to assess for distress. Pulse oximetry is but one tool and should only be one part of our assessment.

Jolie, BSN · Apr 10, 2008

I am not sure why this would mean they are receiving to much O2. Besides the example you gave, why would this be a problem. I have been a nurse a long time and have had many patients on supplemental O2 with an O2 sat of 100%, and have never had anyone physician, nurse or resp say this before. Can someone please explain.

I'm a NICU nurse, so I'll answer this from the perspective of a preemie. Babies with lung disease often require supplemental O2 to maintain adequate oxygenation to their brains and body tissues. While on any type of supplemental oxygen we monitor their O2 sats and attempt to maintain them within parameters set by the neonatologist, usually between 90-95%. If O2 sats are too low, the baby needs a greater concentration of oxygen to meet its body's needs. If O2 sats are greater than 95%, the baby is at an increased risk of developing complications of oxygen therapy, including chronic lung disease and retinopathy. So, at least in most premature infants, oxygen saturation levels greater than 95% offer no additional benefit to the baby's oxygenation status, but do result in greater risk of unnecessary complications.

featherzwolfcloud · Apr 10, 2008

Thanks for the advice guys

aeauooo · Apr 10, 2008

I am not sure why this would mean they are receiving to much O2.

I'd say that if someone on supplimental O2 has a sat of 100% it's time to start weaning them.

While we're on the subject of ridiculous things we've heard docs say; I once heard a resident tell a patient that the reason he kept having such bad gas was that the nurses made him wear a nasal cannula and it was blowing oxygen into his stomach. This resident didn't show the slightest bit of humor when I laughed.

aeauooo · Apr 10, 2008

DaMale Nurse: Good thinking. Allow me to expand on the Bohr Effect...

Are you sure that's not the bore effect?

Really, good job, I just don't feel like thinking that hard right now.

GilaRRT · Apr 10, 2008

Are you sure that's not the bore effect?
Really, good job, I just don't feel like thinking that hard right now.

Yeah, I saw a couple of typos in my post. I could tell a sob story about having to type on a tiny PDA and so on, but the typos are my fault in any event.

However, we are talking about the Bohr effect. Or, was the question a different form of sarcasm? In that case, I understand some may find the material dry; however, it relates to the question at hand. I gave an example of how you could associate a very high HGB satuation with a very serious condition. In addition, the physiology behind the scenario was explained.

aeauooo · Apr 10, 2008

was the question a different form of sarcasm?

Absolutely, which doesn't mean I don't take it seriously - I'm a CCU nurse and I applaud your efforts.

I've just had my face buried in my studies for too long - and I refuse to use emoticons!

GilaRRT · Apr 10, 2008

I understand. It can be hard to guess at intent on forums, so it is better to ask and find out the meaning behind the post.

Otessa, BSN, RN · Apr 10, 2008

I was in a chest clinic yesterday and the consultant told me that if a patient has oxygen saturations of 100% on air and they are not in an anxious state then it is too high. It should be 98 or 99 % max and 100% shows that the person is not breathing properly. Has anyone else heard this?

Not heard that it was a problem. I've worked with Intensivists and Pulmonology and they have never said a peep when the patient had a 100% saturation.....:smackingf

GrumpyRN63, ADN, RN · Apr 11, 2008

I've been told that an o2 sat of 100 % on R/A is not possible, if that's the reading, your oximeter isn't calibrated correctly, I have personally never seen an o2 sat of 100% in > 20 yrs whether the reading ihas been taken on room air or w/ O2 ......

cardiacRN2006, ADN, RN · Apr 11, 2008

I've been told that an o2 sat of 100 % on R/A is not possible, if that's the reading, your oximeter isn't calibrated correctly, I have personally never seen an o2 sat of 100% in > 20 yrs whether the reading ihas been taken on room air or w/ O2 ......

Lol, you've never seen a 100%??? I find that hard to believe.

I guess the pulse ox's I have dealt with have always been wrong...from the ambulance, to the ED, to L&D, to my ICU today. Strange for them all to be so wrong.... :uhoh3:

I guess I'm charting incorrectly as my pt had a pulse ox of 100% all day yesterday.