I'm stuck

Daytonite, BSN, RN · Jul 15, 2007

the order reads: heparin drip at 1000u/hr. you have d5w 1000ml with heparin 20,000 u added. the drop factor is 15gtt/min. the heparin is infused by pump. what is the flow rate?

you want to end up with ml/hour because this is how you program infusion pumps to deliver iv fluids. the information about a drop factor of 15gtts/min is not needed to perform this calculation. it would only be needed if this iv were running by a gravity drip and you had to titrate the number of drops per minute. you don't have to do that with an infusion pump. the infusion pump will deliver the number of ml/hour that you program into it. you use the formula of dose desired divided by dose on hand to primarily set up the equation for dimensional analysis. the rest is just manipulating the positions of the numerators and denominators to end up with a fraction with ml in the numerator and hour in the denominator. also, keep in mind that intially your dose desired divided by dose on hand is going to end up being a complex fraction. the problem is really quite simple to set up:

1000 units/1 hour

(dose desired)

x 1000 ml/20,000 units

(dose on hand) =

50 ml/hour

(flow rate to set the infusion pump)

administer heparin 600u/hr i.v. you have d5w 500ml with 25,000 u heparin added. the drop factor is 60gtt/min. calculate the flow rate.

the set up for this is the same, but i'm not sure about the flow rate. are they assuming you are using a pump or gravity drip. in actual practice we would always put a heparin drip on a pump because accidental overdosage of a patient with this drug can result in hemorrhage. but i'll show you how it works for both situations.

for an iv pump

: 600 units/1 hour

(dose desired)

x 500 ml/25,000 units

(dose on hand)

=

12 ml/hour

(flow rate to set the infusion pump)

for a gravity drip

: 12 ml/1 hour

(amount to give)

x 60 gtts/1 ml

(drop factor of iv tubing--although your problem says 60 gtts/min, tubing drip factors always mean the number of drops per 1 ml of fluid)

x 1 hour/60 minutes

(conversion factor--must convert hours to minutes because that's how we count drops coming out of an iv bottle--by the number of drops per minute)

=

12 gtts/minute

you will notice that the drip rate and the flow rate are the same. this is because iv tubing with a drop factor of 60 gtts/ml always gives you these same results between the mls/hour and the gtts/minute. this is called pediatric tubing and is the only kind of tubing that does this for you.