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What Should We Do?

A twist on drawing blood gases

by Dennis Ernst • January 10, 2020


man in panic

Dear Center for Phlebotomy Education:

When my staff runs out of ABG syringes, they improvise by drawing the sample with a butterfly needle. When I asked about the air in the line affecting results they observed that even with an ABG syringe some air enters so air in the tubing of a butterfly set shouldn't matter. They claim it's easier to obtain ABG’s this way, especially with combative patients. It won't be long before our respiratory department (RT) takes over ABG collections, and we will be training them. The RT supervisor has never heard of their improvised technique and doesn’t want us to train his staff that way. Neither do I. 

The other wrinkle in all this is that I noticed the CLSI standards state that arterial blood should not be used as an alternative to venous blood due to the concentrations of analytes  being different. When I asked the Chemistry supervisor about this, she couldn’t find anything in Tietz or anywhere about constituents varying. Many of our draws in the ICU come from arterial lines, so I really need to know from you what's the bottom line. I can always count on for clarity. What should we do?

My response:

Whenever we hear the word "improvise" in a procedural context we cringe. There's a standard protocol for every blood collection procedure. When staff starts contriving what they think are better ways to do things, it always has repercussions.

If it were acceptable for your staff to draw ABGs with a syringe/butterfly set, it would be in your procedure manual and the industry standards. If your SOPs reflect the CLSI standards, it's not in either. So not only is your staff going against the standards, but they're going against your procedure manual. Unless you step in, they're about to train RT to do the same. Deviations from the standards and your established procedures should always prompt warnings and discipline. It's hard telling what else they've decided "works better" than your standard protocol. We've seen a lot of renegade techniques over the years. Without exception, they always need to be squelched. Staff simply can't be modifying established procedures.

So if they're drawing ABGs through a butterfly, is a syringe attached or a tube holder? If it's a syringe, how they are heparinizing it? Please don't tell us they're transferring it into a heparin tube or even drawing it directly into a heparin tube with a tube holder attached to the butterfly set. Sending ABGs to the lab in heparin tubes goes against the standards. It's the wrong kind of heparin and exposes the sample to subatmospheric pressure in the vacuum tube, altering results. Not only shouldn't they be submitting heparin tubes for ABGs, the techs should know better than to run them. This must be clearly articulated to not only your staff and techs, but to the RT staff.

As for arterial values that differ from venous values, what you said about the CLSI standard is correct. Arterial blood and venous blood differ in concentration significantly for hemoglobin, RBCs, and hematocrit, packed cell volume, lactic acid, ammonia, plasma chloride and glucose. We included this information with references in our latest book, the Lab Draw Answer Book. We just reduced the price, so get a copy for your other supervisor's, too.

Got a challenging phlebotomy situation or work-related question? Email us your submission at [email protected] and you just might see it as a future case study. (Names and identifiers will be removed to assure anonymity.)  

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