Do nurses do med math

[direw0lf]

A pharmacologist teaches our pharmacology class, and I asked her the other day "I know this is important, but I was told that nurses don't actually ever do dosage calculations in the real world nursing, is that true?" and she said yes, the pharm does that for you. I asked what about even checking to make sure an order is correct (because our nursing instructors warned us to always check if an order looks wrong) and she said the pharm always checks that too. But it made me wonder, why are there so many medication errors then? Do nurses do dosage calculations? Thanks.

[KelRN215, BSN, RN]

I don't know about other facilities, but the pharmacy profiles the ordered medication in the Pyxis along with the ordered dose. So when you go to pull it, it'll say "pull X vials". For example, for a 60mg dose of SoluMedrol, you'd select the 40mg SoluMedrol and it'd say "remove 2 vials". Then when you scan the med, it'll say "60mg = 1.5 mL". In your Ativan example, it'd say "1.5 mg = 0.75 mL".

Sure, our pharmacy would do that too but sometimes meds come in more than 1 possible concentration and the one the pharmacy assigned would be empty. We had morphine 2 mg/mL, 5 mg/mL and 10 mg/mL in the pyxis. If the pharmacy had selected 2 mg/mL and your ordered dose was 1 mg, the eMAR would tell you to give 0.5 mL. If the 2 mg/mL drawer was empty and you had to pull the 5 mg/mL or 10 mg/mL, you better know how to do your own med math, lest you overdose your patient by giving him 0.5 mL of 10 mg/mL, 5x his ordered dose.

[sjalv]

Sure, our pharmacy would do that too but sometimes meds come in more than 1 possible concentration and the one the pharmacy assigned would be empty. We had morphine 2 mg/mL, 5 mg/mL and 10 mg/mL in the pyxis. If the pharmacy had selected 2 mg/mL and your ordered dose was 1 mg, the eMAR would tell you to give 0.5 mL. If the 2 mg/mL drawer was empty and you had to pull the 5 mg/mL or 10 mg/mL, you better know how to do your own med math, lest you overdose your patient by giving him 0.5 mL of 10 mg/mL, 5x his ordered dose.

If the profiled dosage isn't in stock, it is greyed out and we cannot select another dose unless the pharmacy has profiled it, in which case it would still tell you the ordered dose and how many mL to give. So if the patient is ordered 2-4 mg Morphine IV push hourly as needed, and the 4mg vial isn't in stock, you can't pull an 8mg vial because that isn't what is profiled. You would have to go to another Pyxis or call pharmacy and let them know it is empty.

[windsurfer8, BSN, RN]

Any med you administer you are responsible for. Telling your head nurse "well my instructor from college said I don't need to check the dosage I am administering" won't turn out well for you. You absolutely positively need to know you are giving the correct med to the correct patient in the correct dose. You are an adult now. What "someone told you" won't mean ANYTHING in court.

[Courtney Nurse Writer, BSN]

I mix the biologics to be infused to our patients. I use dosage calculations on a daily basis!!!!!! We have a new nurse in our department who has a hard time figuring out how to get 25mg of Benadryl out of 50mg vial......... Yeah kinda scary right.

[applesxoranges, BSN, RN]

Not necessarily true. We do minor med math. In the ER, we may have to reconstitute a medication so if I have to give X amount of this drug IM and I use X amount of fluid to mix it, how much would I give? Usually kids are the issue since everything is weight dependent. If kid weights X and the dosage is 10 mg/kg, how much motrin will I give them? We had one hospital that would calculate the orders but current hospitals they like to throw in 10 mg/kg and let the RN calculate it out. Then after you get the dosage, you need to figure out how much motrin to get.

Pharmacy does not usually check ER orders unless we request them to.

[direw0lf, BSN]

Any med you administer you are responsible for. Telling your head nurse "well my instructor from college said I don't need to check the dosage I am administering" won't turn out well for you. You absolutely positively need to know you are giving the correct med to the correct patient in the correct dose. You are an adult now. What "someone told you" won't mean ANYTHING in court.

Yes you're right. Our teacher just told us the other day that if we think an order is wrong we call the physician. If he still says give the order, and we still think it's wrong, we call pharmacy. If they tell us to still give it and we still think it's wrong, we tell our nurse manager. We were told as long as we document all that telling, it's not on the RN who administers it if it was the wrong medication/dose. But my lab teacher made a big point about needing to check and calculate correctly.

[ccer99]

I do math everyday...and I had a pharmacist make an error mixing double concentrated levophed last night. When we program meds into the pump there are different choices depending on concentration as well. Plus, in a code you need to pull straight from the code cart and RSI box yourself, no one to precalculate those meds.

[Katie71275]

I do med calculations. Not a lot because yes they are calculated but I work in L&D so I give the same drugs over and over again I always check over and make sure I am doing it correctly. We also have smart pumps that have our meds loaded and we just select what concentration we are giving but you still need to make sure it's right.

[Here.I.Stand, BSN, RN]

I thought of this thread today as I was doing med math. I had to give KCentra, which is dispensed from the blood bank. I had a number of units on the label, and could see how many mls in the syringes. Ordered dose was 1500 units, and the syringes contained a total of 2000some units. Had to do med math!

[BeachsideRN, ASN]

Of course. Sometimes you also have to dilute very low doses of meds into reasonable doses. I.e giving 6.25mg Benadryl iv when your vial is 50mg/ml. You need to dilute in saline to give the proper dose. Because that dose is 0.125ml out the vial. And sadly I've seen a nurse not be able to figure out to dilute it and give 1.25ml and call the md and tell them that the order is ridiculous and they could never give 0.125ml Benadryl (6.25mg)

[WoosahRN, MSN, RN]

I do calculations every single shift. I'm in PICU and all our dosing is based off of weights of the pediatric patients. Many times our dosing is ordered as x/kg and we'll calculate it on the spot if we are doing procedures (intubations, lines, sedation). Codes? We have code sheets but everything is double checked independently as well (especially if we can anticipate the need). Drips are hand calculated by two nurses. You don't rely on the pump, you have to be able to do the calculations. That goes for starting and titrating a drip. Dosing insulin. Same deal. Need to know all the equations and plug in their info (correction doses, carb dosing).

When hired I have to pass a math test BEFORE I can pass any meds and do an annual math test as well.

Definitely need to be comfortable with math. Can't believe it would even be uttered in nursing school that nurses don't need to do math. 😕

[KelRN215, BSN, RN]

Yes you're right. Our teacher just told us the other day that if we think an order is wrong we call the physician. If he still says give the order, and we still think it's wrong, we call pharmacy. If they tell us to still give it and we still think it's wrong, we tell our nurse manager. We were told as long as we document all that telling, it's not on the RN who administers it if it was the wrong medication/dose. But my lab teacher made a big point about needing to check and calculate correctly.

Well your teacher is wrong. You are responsible for your own practice. If you administer the med despite thinking the order is wrong, it's on you. It absolutely would be on the RN who administered the incorrect dose. In the situation you describe, it behooves the nurse to refuse to administer the medication.