Is My Thinking Flawed?

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Specializes in Oncology.

On my unit we give a lot of potassium and magnesium. They're both ordered to go at 25ml/hr. Often if we have a line crunch we'll dump them both in a buretrol together. People then run this at 25ml/hr. My thinking is that the mix should be able to run at 50ml/hr, as long as they're evenly mixed. Wouldn't this be equivalent to running them separately, but at the same time, at 25ml/hr each? I understand wanting to be cautious with electrolytes. Would you feel differently if I was talking about two compatible antibiotics?

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Specializes in MICU, SICU, CICU.

What is your area of practice? just curious.

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Specializes in ICU.

Potassium should infuse at 10 mEq per hour. It is dangerous to give it faster than that, although sometimes it can be given at 20 mEq per hour. "25 cc per hour" is meaningless; it depends on how it is mixed/diluted. Although magnesium can actually be given fast, the body absorbs it better if it is given slow. 2 gms of magnesium is usually given over 4 hours (2 gms/100cc/at 25 cc per hr=4 hrs) for that reason.

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The volume changes with an additional mixture, so your time will be longer, but as the pp stated, the

rate for K is 10mEq per hour, and mag is over 4 hours.

I would have conversation with pharmacy regarding this--and use your medication book. K should never run in too quickly, can cause arrythmias, and mag is better absorbed at a slower rate.

If you are using a buretrol, are you in pediatrics? Even moreso to have pharmacy involved. In some facilities, K is a "high warning" drug. Take the time to do the math--and if you are in pediatrics, it also is a matter of mg per kg as well, no?

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Specializes in Oncology.
Potassium should infuse at 10 mEq per hour. It is dangerous to give it faster than that, although sometimes it can be given at 20 mEq per hour. "25 cc per hour" is meaningless; it depends on how it is mixed/diluted. Although magnesium can actually be given fast, the body absorbs it better if it is given slow. 2 gms of magnesium is usually given over 4 hours (2 gms/100cc/at 25 cc per hr=4 hrs) for that reason.

40 mEq of potassium in a 100 ml bag- so over 4 hours at 25 ml/ hr- 10 mEq per hour. The mag bags are 4gms in 50 ml that we give over 2 hours when given separately. The doses weren't really vital to this question, since the ordered rate on both of these is 25 ml/hr.

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Specializes in Oncology.
The volume changes with an additional mixture, so your time will be longer, but as the pp stated, the

rate for K is 10mEq per hour, and mag is over 4 hours.

I would have conversation with pharmacy regarding this--and use your medication book. K should never run in too quickly, can cause arrythmias, and mag is better absorbed at a slower rate.

If you are using a buretrol, are you in pediatrics? Even moreso to have pharmacy involved. In some facilities, K is a "high warning" drug. Take the time to do the math--and if you are in pediatrics, it also is a matter of mg per kg as well, no?

I'm in adult BMT. We use the buretrol just to have a way to mix the two meds together- in the buretrol. My question isn't about dose so much. It's if two meds that both go at 25ml/hr are mixed together, isn't running the mixture at 50ml/hr the same as running them separately but simultaneously together at 50ml/hr? I guess not because the 150 ml mixture would go over 3 hours, meaning I'd be giving 40 of k in 3 hours, which is too fast. Posted this while I was tired last night! It's all much clearer today!

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Specializes in MICU, SICU, CICU.

Mag is a potent vasodilator and should be given 1 gm/hr. Slow it down if hypotension occurs. Kcl should be given at 10 mEq/ hr peripherally as Jade stated above. Check your hospital policy. I have never heard of Kcl and Mag Sulfate together. I would not cosign what you are suggesting. Were you serious about mixing two compatible antibiotics in a Buretrol? If your pt had an allergic reaction how would you know which antibiotic caused it? Please talk to your unit educator and pharmacist.

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Specializes in Oncology.
Mag is a potent vasodilator and should be given 1 gm/hr. Slow it down if hypotension occurs. Kcl should be given at 10 mEq/ hr peripherally as Jade stated above. Check your hospital policy. I have never heard of Kcl and Mag Sulfate together. I would not cosign what you are suggesting. Were you serious about mixing two compatible antibiotics in a Buretrol? If your pt had an allergic reaction how would you know which antibiotic caused it? Please talk to your unit educator and pharmacist.

I wouldn't do it with the first dose. Our patients get meds simultaneously all of the time. Some of our patients get 50 IV meds a day. It wouldn't matter if I mixed them or if they were running on two separate pumps simultaneously, I still wouldn't know which caused the reaction. The mag running 4gm over 2 hours is the ordered rate. If they flush or drop their pressure, it's slowed and all future doses are given slower. Mixing mag and k is pharmacy blessed. If there's a shortage and we're not stocking it on the floor, they'll sometimes mix it for us. None of what I give is peripheral. All of my patients have CVL's.

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Specializes in Critical Care.

You're math is correct, so long as the concentrations are the same as what you would run 25ml/hr for each, then the combined rate would be 50ml/hr. Think of it this way, if have Kcl and Mag running separately on their own pumps, and you Y the Kcl and Mag together below the pumps, what rate is that Kcl/Mag combo running at? Whether you combine them above or below the pumps makes no difference.

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Specializes in Critical Care.
Mag is a potent vasodilator and should be given 1 gm/hr. Slow it down if hypotension occurs. Kcl should be given at 10 mEq/ hr peripherally as Jade stated above. Check your hospital policy. I have never heard of Kcl and Mag Sulfate together. I would not cosign what you are suggesting. Were you serious about mixing two compatible antibiotics in a Buretrol? If your pt had an allergic reaction how would you know which antibiotic caused it? Please talk to your unit educator and pharmacist.

I've never heard of a 1gm/hour limit on mag. It's been 2gm/hr everywhere I've worked, unless you work OB. My wife was in the hospital with pre-term labor, she would routinely get 4 gm magnesium boluses over 30 minutes, she was typically getting three or four of these/day.

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Specializes in Critical Care/Vascular Access.

is it possible they're running the K so slowly for the sake of the patient's comfort? Our K-runs are mixed 10meq/100ml and we run at 100ml/hr, but we usually mix in lidocaine for comfort because very few patients can tolerate the runs without it. Maybe the 40meq/100ml mix at 25ml/hr is more tolerable without something added to make it more comfortable?

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Specializes in Oncology.
is it possible they're running the K so slowly for the sake of the patient's comfort? Our K-runs are mixed 10meq/100ml and we run at 100ml/hr, but we usually mix in lidocaine for comfort because very few patients can tolerate the runs without it. Maybe the 40meq/100ml mix at 25ml/hr is more tolerable without something added to make it more comfortable?

The discomfort isn't an issue with central access.

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