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.