Posted by high hopes from IP 121.54.76.9 on March 26, 2008 at 07:30:50:
In Reply to: computation help posted by calyx on March 26, 2008 at 05:51:00:
.. i have a copy of this way back last year, may nag share din, hope makatulong.. God bless.
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I would like to give credit muna sa nagforward din sa akin nito. Nawala kasi ang files dito sa forum ng march. Forward it to your friends din ha!!! Sharing is the Best!!! Good Luck future USRN's
Part H IV DRIP CALCULATIONS
Calculation of Weight Based IV Drips
Drugs can be administered to clients in continuous IV drips. The medication
bag/syringe is labeled with the concentration of medication in the solution (i.e. units/ml,
mcg/ml, meq/ml). The medication order will be used to determine the setup of the problem.
Ratio and proportions can be set up to solve these problems, and depending upon the
complexity of the order several steps may be needed. The following examples will show you
the basis for solving these problems.
A. When the order is written as mg/hr.
Example
Order: Fentanyl 5 mg/hr. The bag is labeled 250 mg in 500 ml of solution.
How fast will the IV need to be infused to give the correct dose?
1. The IV rate will be as an hourly rate, so no conversion needs to be made
for time. If the order was written with a different time, you would need to
calculate the mg/hr. (use ratio and proportion)
2. Put the problem in ratio and proportion.
5 mg = 250 mg 5 (500) = 250 x 2500 x = 10 ml/hr
x ml 500 ml 250 IV rate
B. The order may be written as unit of measurement/ Kg of weight/ hour.
Example
Order: Heparin 100 units/Kg/hr. The label on the solution reads 10,000 units/50 ml.
The patient weighs 70 Kg. How fast should the solution run to give the correct
dosage?
1. First you need the total dosage/hr.
Dose (units/hr) x weight in Kg equals the hourly dose. If the weight is
in lbs, that must be converted to Kg first.
100 units x 70 Kg = 7,000 units/hr
2. Now put the dose in ratio and proportion with the concentration.
7,000 units = 10,000 units 10,000x = 50 (7,000) x= 350,000 x= 35 ml/hr
x ml 50 ml 10,000 rate
C. When the order is written as unit of measurement/Kg of wt/minute.
Example
Order: Dopamine 20 mcg/Kg/minute. The bag is labeled Dopamine 100 mg/50 ml.
The patient weighs 88 lbs. How fast will the IV run to give the dose?
1. First because the weight is in lbs, you must convert lbs. to Kg.
(88 lbs = 40 Kg)
2. Find the hourly dose. Because it is written in mcg/K/min you must multiply
by 60 minutes to get the hourly dose.
20mcg x 40 Kg x 60 minutes = 48,000 mcg/hr
3. Note that the concentration is in mg/ml not mcg, so you must convert to
obtain like units of measure.
100 mg = 1mg x=100,000 mcg/ml
x mcg 1000 mcg
4. Lastly set the problem up in ratio and proportion.
100,000 mcg = 48,000 mcg/hr 100,000x = 2,400,000 x = 24 ml / hr IV rate
50 ml x ml
Practice Exam #7
1. Order: Morphine 5 mg/hr. The syringe is labeled 100 mg/ 100 ml. How fast will the
IV run to deliver the correct dosage? ___________________
2. Order: Heparin 50 units/Kg/hr. The solution is labeled 1000 units/ ml.
The patient weighs 10 Kg. What is the correct rate? __________
3. Order: Dobutamine 10 mcg/Kg/min. The bag is labeled 1 mg/ ml. The patient
weighs 23 Kg. What is the correct rate? ____________________
4. Order: Pitocin 5 miliunits/minute. The bag is labeled 10 units/liter. What is the
correct rate?___________________
5. Order: Ritodrine 0.05 mg/min. The bag is labeled 0.15 gm/500 ml. The patient
weighs 198 lbs. What is the correct rate in ml/hrs?__________
PRACTICE EXAM #7 ANSWERS
1. 5 mg = 100 mg
x ml 100 ml
100x = 500 ml
x = 500 = 5 ml/hr. rate
100
2. a. 50 units x 10 Kg x 60 min = 30,000 units/hr
b. 30,000 units = 1000 units
x ml 1 ml
1000x = 30,000 (1)
x = 30,000 = 30 ml/hr IV rate
1000
3. a. 10 mcg x 23 kg x 60 min = 13,800 mcg/hr
b. 13,800 mcg = 1 mg
x ml 1 ml
NOTE: You must have like units of 1mg = 1000 mcg
c. 13,800 mcg = 1000 mcg
x ml 1 ml
1000x = 13,800 (1)
x = 13,800 = 13.8 ml/round to 14 ml/hr
1000