Cord Blood Gases

Specialties Ob/Gyn


Ok, I have a question for all you experienced L&D RNs...

We did a c/s for a patient with fetal distress, late and variable decels into the 60s and FTP. We get into the uterus and the cord is an occult cord, coming down with the head of the baby who was asynclitic (sp?)...So out comes the cord first. VERY difficult delivery of the head, the way the baby was lying the face was coming out of the incision first, didn't fit, tried to push the baby back up into the uterus, rotate the head so that they could get the vertex out first, still no luck, something like 5+ minutes trying to get this kid out, all the time the cord is out and compressed, flasid and pale, the baby's face was blue+, we heard a cry when we first got into the uterus, but than, nothing no movement, nothing. SO doc finnaly takes the bandage scissors from me and extends the uterine and cutaneous incisions, finnaly making enough room to get this kid out. This is some 8-10 minutes after the first incision into the uterus and the baby's first breath. The baby is dark blue on delivery, and basically looks dead Apgar of 1 at 1 minute...Neo for delivery and codes the baby Apgar of 9 at 5 minutes. We send gases which come back good venous was something like 7.4 and normal base excess (-1.5) PO2 and CO2 were both in normal range as well. Arterial gases were good as well.

My question is are these gases really accurate? This cord was compressed and flacid for more than 5 minutes, most likely there was little to no perfussion, the baby did take it's first breath when we got into the uterus (5+ minutes before delivery), and the gases were obtained from a section of the cord below where the cord was compressed and out of the uterus, and the OB had to squeez blood from the placental end into the section that was sent for gases.

Can anyone explain this to me? Some of the nurses said that this was accurate, but can't really explain why? I don't think that they are, d/t the above facts, but would really like to understand this better.

I am in nursing school and have a pretty good understanding of the physiology. This was the scarriest delivery I ever attended, I really thought we were watching this baby die in front of us! I got teary eyed when I saw that this baby was doing good in NICU. The little guy did well and went home with mom on schedule.

Thanks to any of you all that could explain this one!

Nicole, OBT


829 Posts

Wellllllllllllllll......having not been there, it's hard to say. Some people say cord gases are accurate, some say they aren't. It's kind of a quiet 'controversy' in OB.

Personally, from the way you tell the story, if the blood had to be squeezed from the placental end into the cord to get the gas, it was probably mom's blood gas, not baby's, and therefore inaccurate.

I've seen a couple of cord gases I didn't believe, but ususally it was due to questionable collection technique, such as you described here.

HOWEVER, it's really hard to say not having been there myself to see, so I can't really say for sure.

Anyone else wanna take a crack at it? :)


43 Posts


Thanks for the reply. I know it's hard to make a judgment on something that you did not see personally. I agree it is a bit of a controversy up on L&D, but I really think that most the time, with good technique and fast analysis, it probably is accurate, just not this one (bad technique and the cord was basically 'clamped' right when we got into the uterus). However, some of the girls I work with, when asked about this say that they are absolutely accurate, but don't really explain why. Neo said the kid has a good outlook and most likely will not have any long term effects, since kids are so resilient! So basically good outcome. I just like to figure these things out, the human body facinates me.

Thanks again,


Jolie, BSN

6,375 Posts

Specializes in Maternal - Child Health.

I would have to agree with Shay that since blood was squeezed from the cord to obtain the gasses, they probably reflected the values of the blood from above the compressed area where oxygenation was not compromised and therefore the results would be normal. I don't believe that they would be a reflection of the mother's status unless they were actually drawn from a vessel on the maternal side of the placenta, though.

Did the baby have a gas drawn during the resuscitation or on admission to the NICU? That would be interesting to see.

Babies are very resilient. Remember that in utero, the p02 of arterial blood is only about 25-35, which helps account for why some babies do very well despite such ominous beginnings. I'd be interested to see the initial pH. An extremely low pH (

Angel Baby

46 Posts

I doubt that these gases reflect the baby--if blood was squeezed from the placenta into the cord to draw the gas AND the cord was flacid for minutes before the delivery then this gas CANNOT reflect the fetal status--it's just reflecting the placental reserve.

The 5 minute Apgar is a good prognostic indicator for long term morbidity and it was great. This is validated by the positive neonatal course. Angels were in the room--but then, they usually are in OB.


43 Posts


Thanks guys for the responces. It just didn't make any sense to me. It's nice to have somebody explain it and point out the obvious. I am "just a tech" so sometimes the girls are reluctant to validate my educated guesses. I like learning about OB and hope to be a L&D RN next year! It's nice to have some support.

Renee, are there as many Angels visiting around your L&D as mine? Lately we have been doing 5+ deliveries on nights!!


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