How do you check your SvO2?

Specialties CCU


Specializes in CVICU.

In the event that you lose your SvO2 readings and have to recalibrate it by drawing a sample, what type of container does your sample go in? Someone in the lab told me yesterday that it needed to be in a heparinized syringe and I wondered why not just put it into the vacutainer tubes like you would for any other blood gas sample such as abgs or venous blood gases. If you can check venous blood gases drawn from a central line by placing them into the little plastic green-top tube then couldn't you do the same for SvO2?

While I'm at it, what do you do to ensure that your SvO2 readings are accurate when a patient has a swan in for multiple days? Seems like they always read something crazy after they've been in for awhile.

Specializes in MICU/SICU.

We don't have continuous SVO2 - yet, it's coming soon and we've had an inservice - but I'm pretty sure our VBGs and SVO2s go into a heparinized ABG syringe, I haven't actually drawn one myself in a while (we have techs who draw a lot of our labs).

When we draw ABGs we make sure to clear all the extra air out of the syringe to prevent O2 from being absorbed into the sample resulting in a false reading. Wouldn't the same hold true for VBGs and SVO2s?

Specializes in CVICU.

Well yes but the problem with the syringes that we have supplied to us is that they are not like a normal syringe because when you pull back on the plunger to aspirate your sample it does not provide much suction and air gets mixed into it, elevating the SvO2 higher than what we would expect. It doesnt have suction because it it's the same one that would be used to stick for ABGs peripherally and those are supposed to fill on their own once the tech sticks the artery

We use a heparinized ABG syringe that we'd draw off an a-line with to get a gas.

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