Co-oximetry in the Cath Lab

Our Cath lab is currently considering going to I-STAT. The measurement is indirect but it is correlating with AVOX. This will help our compliance issues by using one instrument for all testing. Staff is divided at the moment about the length of time it takes to perform a test but I do know other Cath labs that switched to I-STAT. 

Jennifer, what cartridge are you using on the iSTAT for this? TIA

@Jennifer - considering that the AVOX reports oxyhemoglobin (O2Hb, not sO2) and the iSTAT can only report a calculated sO2 result (not the same test) - I am curious how you can say they are correlating?  It may appear that they are correlating but that is likely because without a significant contribution by dyshemoglobins (CoHb and MetHb), O2Hb is often close to the sO2 value.  But that correlation disappears in cases where the dyshemoglobin contribution rises - an iSTAT calculated sO2 will appear "normal" while the O2Hb could actually be quite low.

I agree @James and was hoping some of you had some more input. I just started the study and I am waiting to hear back from two Cath labs that replaced their Avox and Hemochron for I-STAT because I had a lot of questions and concerns. If it is acceptable, then it would definitely make my life easier but either way I have to find a solution for the Avox in the next year.  

We use the ABL90s.  We just switched last year from the 80 co-ox to the 90.  They work well, the only issues we have are mainly user errors like moving the instrument but not plugging it back in...eye roll lol.  They do a measured SO2 which was a requirement for our Cath Lab.  They have an Istat but only use it for the blood gas.  On the 90's they only use the SO2 and it gives a Hgb but they like it and there's very little maintenance.

The cuvettes have no expiration date so if you can make it through this crunch, always order plenty in advance and keep up to 3 boxes on hand.  That is what we've done.

Hi Jennifer - there are various analyzers that do a combination of blood gas and cooximetry for which you could simply disable the blood gas parameters if you don't need them.  I don't think there's another analyzer out there that only does cooximetry - only AVOX.  But even if the studies you're doing with iSTAT appear to be correlating, I would think you would be immediately cited for not comparing apples to apples in your validation because they are indeed two different tests (O2Hb and sO2).