arterial vs capillary glucose sample and a disagreement @ work

[november17]

I had a patient that had a PICC line. I did a PICC blood draw for the lab person. After the draw, a CNA ask me to put a dot of blood on the glucose meter. I told them no, and that they needed to poke the patient and get a capillary sample. They got really annoyed and call me "weird."

I've seen a CNA that will trail the lab person around and obtain blood samples as they are drawn venously. Even though it's not the hospital policy to obtain samples for glucose that way.

One of the other RNs rationalized it for me and said, "it causes less trauma to the patient because you don't have to poke them, but whatever."

Am I being too "by the book?" I was really tired and had a really stressful night, and I didn't really want to think about it very much, but my instinct and feeling was just not to do it. I don't want to be inflexible, but at the same time I want to ensure the best care I can give. I know there is a difference in the glucose levels between an arterial and capillary sample but I'm not sure exactly how much the difference can be. I haven't found any reliable source of information about it. The books just all say there is a difference. I guess the arterial sample would be more accurate, but at the same time if the person had always regulated their insulin dose via fingersticks, wouldn't you want to keep it the same?

[november17, ASN, RN]

Check out the journal published by AACN. They recently published a study regarding this very thing. Evidence Based Practice.

Awesome I'll have to see if I can find it somewhere. Ever since I got out of school I lost all my access to academic journals Guess I'll have to pony up some money so I can stay on the cutting edge.

[Virgo_RN, BSN, RN]

I just had a guy with a triple lumen arterial in the right carotid. He ripped it out in a confused state, lost a lot of blood and nearly coded. It happens and it happened in ICU right before his transfer here (ortho/neuro, step-down unit).

I've never heard of a triple lumen arterial line in the right carotid. What is the purpose of this type of line?

[NJNursing, ASN, RN]

I've never heard of a triple lumen arterial line in the right carotid. What is the purpose of this type of line?

I couldn't tell you. With 8 patients and being clinical coordinator, I didn't get to delve into why or when it was put in. I just know it was ripped out and it held up his transfer to our floor for 6 hours until the bleeding had subsided and additional tests were ordered and had come back. I believe he had a CVA and was t-PA'd.

[NotReady4PrimeTime, RN]

There is never an indication for a triple lumen ARTERIAL line. The line your guy had was probably a triple lumen right internal jugular central venous line.

[BBFRN, BSN, PhD]

I agree with everything janfrn has said. Also, if it doesn't have a pressure bag and a transducer attached to it, it's not an art line. The massive bleeding would have been more of a result of the tPA.

Reaching out on a limb here, but maybe the line was incorrectly placed? Did an xray show proper placement? I don't really see this happening, though, because it's pretty easy to tell when the line has been placed in an art vs vein during placement.

Glucose is checked via a-lines all the time in critical care, r/t Q1h accuchecks on the insulin gtt patients.

[NJNursing, ASN, RN]

I didn't have the pt when he was in ICU. He had pulled it out before he had ever come to me. I had gotten in report that it was an arterial line that he ripped out, they had a sandbag on it for 6 hours, q 4 hemogram x 24 hours. He also pulled out his NG tube right afterwards. He came to me with a bandage around his neck with a pressure dressing a good 4 inches high. Needless to say, he had some triple lumen something or other. He's now got a picc line, nice and out of the way and they're trying a 3rd attempt at a PEG tube since he's ripped out 4 NG's in a week.

[starsINmyEYES]

yeah, i agree that if it's less invasive and policies are in place why not kill two birds with one stone, resulting in less trauma to the patient. i mean, i would imagine venous samples are far superior to fingertip samples, especially when you take into consideration that there might be dirt/sugar traces etc on the fingertip to begin with. if you get my drift? very interesting topic though! so thanx for that!

[nyforlove]

Awesome I'll have to see if I can find it somewhere. Ever since I got out of school I lost all my access to academic journals Guess I'll have to pony up some money so I can stay on the cutting edge.

Great Thread! Did anyone locate that article? Thanks.

[hypocaffeinemia, BSN, RN]

i think the article you're looking for is this:

comparison of point-of-care and laboratory glucose analysis in critically ill patients

am. j. crit. care., jul 2007; 16: 336 - 346.

here's the abstract:

comparison of point-of-care and laboratory glucose analysis in critically ill patients

by teresita lacara, rn, bsn, caroline domagtoy, rn, bsn, donna lickliter, rn, kathy quattrocchi, rn, bsn, lydia snipes, rn, joánne kuszaj, rn, msn, ccrn and maryclare prasnikar, rn, msn, ccrn. teresita lacara, caroline domagtoy, donna lickliter, and lydia snipes are staff nurses; kathy quattrocchi is a team leader; joánne kuszaj is a clinical manager; and maryclare prasnikar is a cardiovascular clinical nurse specialist in the medical-surgical intensive care unit at rex healthcare in raleigh, nc. corresponding author: teresita lacara, rn, bsn, intensive care unit, rex healthcare, 4424 lake boone trail, raleigh, nc 27607 (e-mail: [email protected]).

background blood for point-of-care analysis of glucose levels is often obtained from different sources (fingerstick, arterial or central venous catheter).

objectives to examine agreement between point-of-care and laboratory glucose values and to determine effects of hematocrit, serum carbon dioxide, and mean arterial pressure on the accuracy of point-of-care values.

methods point-of-care values were compared with laboratory values. in 49 critically ill patients, blood was obtained first from a catheter for laboratory testing and then from the catheter and via fingerstick for point-of-care testing. bias, precision, and root-mean-square differences were calculated to quantify differences in values between the 2 methods. a t test was used to determine differences in values between each point-of-care blood source and the laboratory value. multiple regression analysis was used to determine if serum level of carbon dioxide, hematocrit, and/or mean arterial pressure significantly contributed to the difference in bias and precision for the point-of-care blood sources.

results mean laboratory glucose level was 135 (sem 5.3, range 58–265) mg/dl. in point-of-care testing, bias ± precision and root-mean-square differences were 2.1 ± 12.3 and 12.35, respectively, for fingerstick blood and 0.6 ± 10.6 and 10.46 for catheter blood. values for point-of-care and laboratory tests did not differ significantly. for catheter samples, hematocrit and serum carbon dioxide contributed significantly to difference scores between point-of-care and laboratory values (p

conclusions glucose values for point-of-care samples did not differ significantly from laboratory values. for catheter samples, hematocrit and serum carbon dioxide levels accounted for the difference between point-of-care and laboratory glucose values.

[PiPhi2004]

We use arterial blood, venous blood, capillary blood, whatever. I have never noticed a big difference (when we send down for blood out of art lines, we get a glucose reading, at MOST it may be one or 2 points off from a fingerstick I have gotten around the same time). If were takin blood out of an art line we always just put a dab on the glucometer if its time to test. It's one less stick for the pt. Maybe glucometers are different models and take different things?