Applying Oxygen when O2sat is 99% on RA

Specialties Ob/Gyn

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I've spent the last few nights pondering this question ... let's use a "hypothetical" patient: Primip, induction (cytotec X2 then Pitocin), Pit is up to 6mu, FHR baseline 140-150bpm with average variability and accels up to 175, UC's q 3-6 minutes, 60-90 seconds long. Late decels are noted, first deep then more subtle (understanding that it is not resolving but that the baby is having more difficulty with the UC's). Patient is repositioned to left lateral, HOB flat and IV open. Mom shows 99% oxygen saturation on RA. FHR return to baseline with no further problems.

Would you put O2 at 8-10L via mask on this patient? Why? My first (new nurse) thought would be to apply oxygen but when I saw her O2 sat at 99%, I hesitated. Another RN came into the room and immediately applied the oxygen mask. After the day was over, I spent some time online searching for evidence proving that oxygen administration would have helped the mom and/or fetus. Interestingly enough, there was nothing that I could find that was definitive regarding supplemental oxygen when mom is already at 99% on RA.

What do you all think? I'd love some other input. Are we applying O2 as a habit without evaluating the moms current O2 saturation? Is it beneficial when she is already at 99%? Would love to hear what you all think about this!

Incidentally, went to the OR for a c/sec (hours after the lates resolved themselves), mom was tired of being in labor and doc was tired of listening to her ask for a c/sec. Bummer, too, since the patient was obese making her post-op recovery harder. No nuchal cord found, placenta looked great and baby labs all WNL.

Thanks ...

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Specializes in Case Mgmt; Mat/Child, Critical Care.

You put the O2 on mom for the baby, not the mom...it doesn't matter if the mom's o2 sat is 99%....your goal is to get more o2 delivered to the baby.

Your response for lates is: 1) turn to lt side 2)put o2 on 3)open IV wide and 4) turn off pit and notify provider.

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Ah yes, forgot to mention that I also turned the pit off and provider was notified, as well (we'd been on the phone off and on for 20 minutes).

I do understand the theory behind putting 02 on the mom for the baby's benefit ... but still do not understand the science behind satting at 99% and additional need for oxygenation (for either mom and/or baby). If you have 99-100% of your total oxygen capacity, does more oxygen actually help? Maybe I'm just being dense here but I've never taken "that's the way we've always done it" as an answer. Anybody have a study or more info on this?

Edited to add: I'm going to research the Oxyhemoglobin Curve for more info .. I'm thinking that with a low H&H, less hemoglobin to carry O2 ... I'm not sure I'm even following myself at this point.

Anymore ideas?

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Specializes in Case Mgmt; Mat/Child, Critical Care.

It doesn't matter what the mom is satting....what you want is the extra, supplemental oxygen to get to the fetus, d/t placental insufficiency (indicated by the lates). Just because the mom is satting 99% does not mean this is what the fetus is getting or theoretically "satting", if you will. That is why we do fetal scalp blood pH monitoring....you will see what the fetuses "true" levels are, so yes, the "extra" O2 we give mom gets to the fetus. Sometimes, though, that is not enough. I'm not sure who's telling you "that's the way we've always done it"....there really is theory behind the method! Talk to your CNS or Educator for more info or check out some Advanced NICU didactics on fetal circulation, etc.

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OKay, I guess I am just being dense about this subject. Just looking for facts to back up my thoughts. Thanks for your help and input! :)

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Specializes in Education, FP, LNC, Forensics, ED, OB.
You put the O2 on mom for the baby, not the mom...it doesn't matter if the mom's o2 sat is 99%....your goal is to get more o2 delivered to the baby.

Your response for lates is: 1) turn to lt side 2)put o2 on 3)open IV wide and 4) turn off pit and notify provider.

Exactly correct, moondancer. This is known as intrauterine resuscitation. This is outlined in the guidelines for fetal distress by ACOG and AWHONN. You should also add, 5) check for cord prolapse.:)

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Specializes in Maternal - Child Health.

Edited to add: I'm going to research the Oxyhemoglobin Curve for more info .. I'm thinking that with a low H&H, less hemoglobin to carry O2 ... I'm not sure I'm even following myself at this point.

Anymore ideas?

You are on the right track to be interested in the oxyhemoglobin curve.

Remember, if a patient is anemic, it is possible for her hemoglobin to be fully saturated with oxygen, and yet the patient still be hypoxic. Conversely, if a patient has an abnormally high Hgb, it is possible for her to be only 80% saturated, appear cyanotic, and yet have an adequate supply of oxygen in her bloodstream.

Thanks for asking these questions. It keeps all of us focused on the scientific rationale for what we do!

Oxygen saturation IS NOT the equivalent of paO2.

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I've done some more reading and research and I'm still in need of more info. Here's where I am at: If mom has an O2 level of 99% then her hemoglobin is carrying 99% of its potential capacity. The only way the fetus gets oxygen (since we can't put a face mask on in utero) is via the mothers blood being perfused through the placenta to the fetus. By optimizing maternal cardiac output (IV open, mom left lateral) we are giving her maximum volume to perfuse the placenta. So ... what is the additional oxygen going to attach itself to if the hemoglobin is already carrying 99% of its capacity? Am I missing something here? It seems that opening the IV and maintaining a lateral position are what truly improves placental perfusion rather than the supplemental oxygen. Now, taking an additonal leap, we could look at giving mom blood which would increase her hemoglobin levels allowing her to carry more oxygen (not that I'm suggesting this is possible, just throwing it out there as a "devils advocate" type of comment).

I hope you don't mind that I'm wanting more discussion regarding this. It is extremely interesting to me and I'm too stubborn not to figure it out. Thanks for all the comments!

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I'm only a student but I am reading it the same way you are- if mom is already at 99-100% no matter how much oxygen she is getting she will not get any more oxygen to the fetus if there is nothing to carry it.

Maybe I am dense too. I probably am, in fact :) . But, I would like to understand also.

Courtney

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Interesting thread! I am curious on this too (student)...

~J

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Specializes in NICU, PICU, educator.

It doesn't matter what the pulseox is reading...that probe is picking up the sat of the cells in that finger at that time. Sometimes, when you draw an ABG on someone that is sating 99, their O2 can be low. There is no way to know if that pulseox is totally correct without doing an ABG.

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Ahhhhh....very good point. I see why this would be done now.

~J

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