O2 Sats..bad if 100%..?

htrn · Apr 10, 2008

I know that with a COPDer that 100% is not always good. Also neonates with some congenital heart abnormalities need to maintain their fetal circulation until heart surgery to correct the abnormaility - so then they keep the sats REALLY SCARY low!!

cardiacRN2006, ADN, RN · Apr 10, 2008

I've worked in hospitals for 12 years, and every time I've checked my sats, I've always been 100%.

So if I'm breathing improperly, then I must be doing a good job at it....

allnurses Guide · Apr 10, 2008

I would ask him to explain the phyisiology behind that statement. As someone already mentioned unless specific medical conditions such as COPD or baby with congential hear defects I can't understand his rationale

Penguin67 · Apr 10, 2008

COPD patients are stimulated to breathe by the hypoxic drive, which is why we'll give them O2, but only at small amounts. That's all of the adult physiology that this pediatric nurse can remember!

PsychNurseWannaBe, 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?

That doesn't make sense to me...regardless of diagnoses because the person is on room air. How do you breathe differently on RA and how would one decrease a sat if you are simply breathing the air around you?

When you said "on air"... did you mean on room air or on O2?

aeauooo · Apr 10, 2008

if a patient has oxygen saturations of 100% on air and they are not in an anxious state then it is too high.

That sounds pretty ridiculous to me.

Remember the old maxim: treat the patient, not the number.

Unrelated to your question, but suggested by the title of your thread, there are a couple of points to be made regarding oxygen saturation.

1. O2 sat is only one component of oxygen delivery. The others are cardiac output and hemoglobin. A high O2 sat does not necessarily mean the person's tissues are being adequatley oxygenated.

2. O2 saturation does not tell you anything about the person's CO2. 100% oxygen saturation doesn't mean that your patient's CO2 is >50, and by definition, in respiratory failure.

3. Pulse oxymetry cannot distinguish between oxyhemoglobin and carboxyhemoglobin: pulse oximetry is meaningless in carbon monoxide poisoning.

Jolie, BSN · Apr 10, 2008

For patients receiving supplemental oxygen, a saturation of 100% is not desirable, as it indicates that the patient is receiving too much 02, which carries risk of undesirable side-effects, such as retinopathy in the premature infant.

But anyone breating room air with a saturation of 100% is just fine, thank you. What would the good doctor have us do to decrease their 02 sats?

PsychNurseWannaBe, BSN, RN · Apr 10, 2008

For patients receiving supplemental oxygen, a saturation of 100% is not desirable, as it indicates that the patient is receiving too much 02, which carries risk of undesirable side-effects, such as retinopathy in the premature infant.
But anyone breating room air with a saturation of 100% is just fine, thank you. What would the good doctor have us do to decrease their 02 sats?

Put them on supplemental carbon dioxide?? :chuckle LOL

cardiacRN2006, ADN, RN · Apr 10, 2008

But anyone breating room air with a saturation of 100% is just fine, thank you. What would the good doctor have us do to decrease their 02 sats?

Maybe I could take up smoking?? :smokin:

mianders, RN · Apr 10, 2008

For patients receiving supplemental oxygen, a saturation of 100% is not desirable, as it indicates that the patient is receiving too much 02, which carries risk of undesirable side-effects, such as retinopathy in the premature infant.
But anyone breating room air with a saturation of 100% is just fine, thank you. What would the good doctor have us do to decrease their 02 sats?

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. :confused:

DaMale Nurse · Apr 10, 2008

There could be a couple reasons o2 sat of 100% are could be bad.

#1. (as before)Carbon Monoxide poisoning

#2. PH of the blood this is known as Borh's Effect. An increase in the ph will cause the Oxyhemoglobin Dissociation Curve (http://www.ventworld.com/resources/oxydisso/dissoc.html) to shift to the left. Meaning that you will get a higher O2 sat despite lower PaO2. So a 100% sat on a COPD could mean uncompensated respiratory acidosis.

#3 2,3-DPG or 2,3-Disphosphoglycerate (is an organophosphate, which is created in erythrocytes during glycolysis) shifts the curve to the right. Meaning lower sat's despite good PaO2. This chemical is thought to be adaptive for as it is seen in increased levels with a patient with a diminished peripheral tissue O2 availability, like COPD, Anemia, CHF. So it's not likely to be a problem but it shows that the body could possibly compensate for Borh's effect over long term.

#4 Hypothermia causes a left shift of the curve (high sats but less PaO2) Hyperthermia causes a right shift of the curve (lower sats but higher PaO2)

#5 Methemoglobinemia(a form of abnormal hemoglobin) causes a left shift in the curve.(high sats but less PaO2)

$6 CO2 will cause the curve to shift (left for high, right for low)

#7 Fetal Hemoglobin will cause the curve to shift left. (lower sats for more PaO2)(That's why it so important not to have high sat's on newborns. The PaO2 is already sufficient at the lower sats, more just doses damage)

Anyhow, check out this site if you want to know more about the O2 sats. I think I covered them all but I might have been a bit unclear.

http://www.ventworld.com/resources/oxydisso/dissoc.html

DaMale Nurse (truly a nerdy one)