A lil Baffled about ML/HR on Infusion pumps

stressgal, RN · Feb 11, 2006

You set the infusion rate based on the prescribed order. Is that what you're asking. I may not be clear.

elkpark · Feb 11, 2006

The rate (ml/hr) is the same regardless of the size of the bag of fluid. The order for the IV should specify the rate, or might be written "kvo" (for "keep vein open"). If it just says "kvo," your facility will have an IV policy/procedure in the Nursing P/P manual that defines what the official kvo rate is for your facility (often, 10 or 15 ml/hr, but there's a lot of variation out there). Sometimes, you see orders written as "Infuse (X amount) over (X) hours" (I think we see a lot less of that than we used to), but, again, you do the math the same way regardless, just plug the different numbers into the formula.

Typically, smaller bags of fluid are used for "slow" rates llike that (20 ml/hr) to avoid waste. Facilities have policies about how often a single bag of IV fluid can hang before it must be changed, and, if you started an IV at 20 ml/hr with a 1L bag, you could easily end up throwing away a good part of the bag because of the time limit on how often you must replace the bag. But, if the order is written for "NS at 20 ml/hr," the rate is 20 ml/hr regardless of the size of the bag of NS used.

Daytonite, BSN, RN · Feb 11, 2006

Today's IV pumps are almost all programmed to deliver milliliters per hour (mL/hr). Some can be programmed so the length of time is in minutes rather than hrs. After all those IV calculation questions in nursing school about drip rates, it makes you wonder why you had to learn that stuff. 20mL/hr. would be what I would call a "keep vein open" or KVO rate. It's just barely enough fluid infusing to keep the IV access patent. And, if the tubing has a macrodrip drip chamber you are hardly going to see any fluid dripping (I think that is what you are asking isn't it?) I assure you that as long as the pump is operational it is indeed infusing the IV fluid at 20mL/hr. In order to see one drop of fluid, you'd have to stand by the pump for awhile waiting to see some fluid being pulled into the drip chamber by the pump. It does kind of drive you batty trying to assess whether the pump is working or not.

The way most of these pumps work is that the pump pulls one or two mL of the IV fluid into the drip chamber at one time to replenish it's supply of fluid. If you watch an IV pump programmed to go at a faster rate, you will see this happening. There are other models of IV pumps that will pull fluid into their drip chambers as they need it very much like a normal gravity drip IV. Each pump manufacturer programs their pumps to perform a little differently. However, the principles behind them are basically the same. If you get the name and manufacture of a particular IV pump you might be able to get more specific information on how it performs from a website set up by the manufacturer. We have so many different companies making these pumps these days here in the states, that there is no way to know them all.

What I do to assess if the pump is working properly is to pinch off the tubing about 8 inches (about 20 cm) just below the pump. Don't pinch off tubing too close to the patient end or it will take forever for the pump to detect the obstruction. If the pump is working properly, in a little bit of time the pump will detect the obstruction and start alarming. Let your pinch go and reset the alarm. The pump is indeed working and pumping at 20mL/hr. as it was programmed to. Another thing you can do to assess and assure the patency of the IV cannula is to flush the line with an IV push of 2 or 3mL of saline. That is probably a good idea anyway in order to clean any of the biological slime (fibrin sheath) that likes to form around IV cannulas and slide over around the tip of the cannula. Those fibrin sheaths are an absolutely normal body mechanism to a foreign body and can work like a flapping lid that can cause no end of aggravation with patency. The longer an IV cannula is dwelling in one particular site, the more likely this fibrin sheath is going to form (only takes 24 hours) on it's exterior. Faster IV rates prevent this sheath from folding back on itself and causing occlusions of the tip of the cannula. (This fibrin sheath or sleeve folding back onto the hole in the tip of the IV cannula is why you don't always get a blood return when aspirating from an older IV site. It's very aggravating.) I routinely flush KVO IV's and saline/heparin locks at the very beginning of my shift to assess the patency of the IV device. I do this because I don't like finding out an IV isn't any good just as I'm about to hang a dose of a patient's IV antibiotic. Just be careful that you don't push the saline into the vein too fast--the smaller the syringe, the higher the pressure in the syringe, and you want to keep things nice and easy when pushing fluids into a vein.

Hope this was the explanation you were looking for.

AussieKylie · Feb 12, 2006

Thank you all for your explanations, I appreciate your help.

This may sound strange, but I do have a small fear in programming infusion pumps - only because my facilitator during practicum, put the fear in me :eek: . As she thought I had a calculation problem, and the problem was that I was not used to seeing or working with a Baxter Infusion Pump :angryfire .

N E ways, thank you all alot for your help :wink2:

Daytonite, BSN, RN · Feb 12, 2006

whenever i've gone into a new facility and they have an iv pump i've never worked with before i try to find an instruction manual for it. sometimes they're just not there; sometimes they are tucked away on a shelf somewhere. if i can find a page of instructions i'll try to xerox it to carry on my clipboard. most pumps today have basic operating instructions on their sides now. i will try to get myself and a pump alone somewhere and just sit and play around with the thing to get the hang of it.

the pumps are just so much more convenient. 20-30 years ago the iv pumps were reserved for icu use and people on things like insulin or aminophylline drips. everything else was gravity flow and we had to count the drops to make sure we had the right rate. kvo lines had pediatric tubing on them (60 drops/min) and had to be titrated to 30cc/hr which is what we ran them at. that's one drop every 2 seconds. on top of all that, the first setting of the roller clamp was never perfect. i learned to check the iv line about 15 minutes after adjusting a rate because no matter how careful i was to count the drops per minute it seemed like after i walked away, the tubing and clamp had time to "relax", or something. i would go back and find the iv dripping faster than i had set it--always. i've never been able to figure out why that happens, but after screwing up a couple of infusions i learned to check those gravity drips frequently--like at least once an hour. we would also occassionally get a patient or two who would reach up and play around with the roller clamp. yup! pumps are much better and a real time saver.

our profession is getting filled with all kinds of technical gadgets. it really is important to just take some time to sit down with each of these gizmos and play around with them to figure out how they work. learn what makes them alarm and how to cancel it. doing that really enhances their value as time savers in our work world and makes our jobs so much easier.

here's a simulation of an iv pump you might want to play around with a little bit. it has 5 iv infusion questions programmed into it for you to answer and practice on the pump with. remember to turn the pump on (click on the on button) or the thing won't work for you! (i'm sure that was programmed into this simulation deliberately. want to feel stupid? forget to turn a device on and get angry while you try to figure out why it won't work! :banghead: )

http://classes.kumc.edu/general/ivpump/ivsimulation.html -- this is a cool iv pump simulator from the university of kansas! there are 5 case studies (iv questions) for you to practice on the pump with. follow the instructions on the left side of the page.

stressgal, RN · Feb 12, 2006

Daytonite,

You always have the best advice and web pages. Thanks!

kellster · Oct 14, 2006

I am having trouble figuring out how fast to run different medications on the IV pump. I think that I am making it way to hard than it is. Any ideas?

Daytonite, BSN, RN · Oct 14, 2006

Hi, kellster!

The best thing to do is to refer to a nursing drug handbook or call the pharmacist at the facility where you are infusing the IVs. Most facilities also have a procedure or policy manual for the nurses that tell you how fast they want medications infused.

Welcome to allnurses! :welcome:

CarVsTree · Oct 17, 2007

I am having trouble figuring out how fast to run different medications on the IV pump. I think that I am making it way to hard than it is. Any ideas?

Yes you probably are making it harder on yourself. I'm sure in NS they're teaching you to figure out drip rates (i.e. how many drips per ml - I think). We don't do that in real life.

Since, I'm sure as a student you won't be allowed to call pharmacy for the answer here's how you do it.

I frequently hang Vancomycin which comes in a 250ml bag and is ordered to be infused in 1 1/2 hours.

So you HAVE 250 divided by 1.5 and you GET 166.666666 or 167ml/h. It's much simpler than nursing school because in school they would want you to figure out the drip rate. Please don't ask me to do that!?! ;-)

If you have to hang TPN at my hospital, the pharmacy will just tell you the rate to hang it at. 83ml/h for example.

If you need to hang 50ml of ATB and give it in 30 minutes. You would be dividing 50 by 1/2 in algebra you cross multiply and come up with 50 x2 / 1 and get 100. I just multiply by 2.

I was confused by pumps when I got to clinical. They were so simple I was trying to figure out this complicated math problem and you just put in the rate you want.

Help???? I hope so!