Dopamine and Dobutamine Computations

for DOPAMINE, the constants are
single dose = 13.3 (translates to 200/250 or 400/500)
double dose = 26.6 (translates to 400/250 or 800/500)

... for DOBUTAMINE, the constants are
single dose = 16.6 (translates to 250/250 or 500/500)
double dose = 33.3 (translates to 500/250 or 1000/500)

the formula for the above computation is always...

DOSAGE x WT
___________
constant

FOR THE EXPLANATION OF CONSTANT:
notice in the sample computation of double-dose dopamine: pt wt. 176lbs. doctor ordered 5mcg/kg/MIN. available is 400/250 DOPAMINE in D5 water. how many ml/hr to give?

(5 mcg / kg min) x (80 kg) x
(250 ml / 400 mg) x (1 mg / 1000 mcg) x (60 min / 1 hr)

if we summarize the 2nd line, this can be reduced to:
(5 mcg / kg min) x (80 kg) x (0.0375 ml min / mcg hr)

the short-cut it is:

(5 mcg / kg min) x (80 kg)
________________________________
26.6 <-- (this is the RECIPROCAL of 0.0375)

: so in actuality the unit of 26.6 is (mcg hr / ml min)

WHY IS THERE A NEED TO KNOW THE CONSTANT?
IN SOME CASES, 400/250 IS NOT BEING MENTIONED IN NCLEX... SOMETIMES THE QUESTION WOULD BE LIKE

pt wt. 176lbs. doctor ordered 5mcg/kg/MIN. available is DOUBLE-DOSE DOPAMINE in D5 water. how many ml/hr to give? so in this case we know that we will be using 26.6...

for the rest of the computation... just remember to elimitate the UNITS thru multiplication process in order to come up with the CORRECT DESIRED UNITS... REMEMBER YOUR CONVERSION FACTORS FOR TIME,WEIGHT & VOLUME......

lets have an example...

Infuse Nitroprusside 25 mg in D5W 250 ml at 50mcg /min using microdrip tubing.Determine the ml/hr and the gtts/min.

Given:
25 mg/250 ml ( there is 25 mg NA Nitroprusside PER 250 ml...based on the given)
50 mcg/min
60 mcgtts/1 ml <---- microdrip

Find: ml/hr :
(250ml/25mg) x (1 mg/1000 mcg) x (50mcg/min)

= 0.5ml/min
= (0.5ml/min) x (60min/1 hr) = 30 ml/hr <---answer

Find: gtts/min :
(30ml/hr)x(60gtts/ml)x(1hr/60min)
= 30 gtts/min <----answer

example 2

Infuse Dobutamine 500 mg in 250 ml D5W at 5 mcg/kg/min using microdrip tubing.The client weighs 182 lbs. Determine the ml/hr and the gtts/min.

Given:
500mg/250ml (this is double-dose dobu)
5 mcg/kg/min
182 lbs
60gtts/ml <------- microdrip

Find:ml/hr
182 lbs x (1kg/2.2lbs) = 82.7kg

(5 mcg/kg min) x (82.7kg) = 413.5 mcg/min

413.5 mcg/min x 1mg/1000mcg = .4135 mg/min

.4135 mg/min x 250ml/500mg <--- ML is the numerator since were looking for ML/HR
= 0.20675ml/min

= 0.20675ml/min x (60 min / 1 hr) = 12.4 ml/hr <--ans

... using the short-cut: 33.3 is constant for double dose dobutamine...
5mcg/kg-min x 82.7kg divide by 33.3 = 12.41 ml/hr <--same answer.^^

Find: gtts/min
12.41 ml/hr x (1 hr/60 min) x (60gtts/ml) =
= 12 gtts/min... <---answer (Drops Per Minute MUST always be in WHOLE NUMBERS while ml/min, ml/hr,etc may have decimal points)

Ear Drops Administration

1. Wash your hands with soap and warm water and dry them thoroughly.
   
2. Carefully wash and dry the outside of the ear, taking care not to get any water in the ear canal.
   
3. Warm the ear drops to body temperature by holding the container in the palms of hands for a few minutes. Do not warm the container in hot water. Hot ear drops can cause pain, nausea, and dizziness.
   
4. Shake the container.
   
5. Tilt your head (or have the patient tilt his or her head) to the side or lie down with the affected ear up. Use gentle restraint, if necessary, for an infant or a young child.
   




6. Open the container carefully. Position the dropper tip near, but not inside, the ear canal opening. Do not allow the dropper to touch the ear, because it could become contaminated or injure the ear. Ear drops must be kept clean.
   
7. Pull your ear (or the patient’s ear) backward and upward to open the ear canal, as shown in the picture above. If the patient is a child younger than three years old, pull the backward and downward, as shown in the picture below.
   
8. Place the proper dose of number of drops into the ear canal. Replace the cap on the container.
   
9. Gently press the small, flat skin flap over the ear canal opening to force out air bubbles and push the drops down the ear canal.
   
10. Stay (or keep the patient) in the same position for at least five minutes. If the patient is a child who cannot sit still, the doctor may tell you to place a clean piece of cotton gently into the child’s ear, to prevent the medication from draining out.
    
11. Repeat the procedure for the other ear, if directed to do so.
    
12. Gently wipe any excess medication of the outside of the ear, using caution to avoid getting moisture in the ear canal. Wash your hands.
    

Drugs and Dosage

Part H IV DRIP CALCULATIONS

Calculation of Weight Based IV DripsDrugs 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.

ExampleOrder: 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/hrx 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 correctdosage?
1. First you need the total dosage/hr.Dose (units/hr) x weight in Kg equals the hourly dose.
If the weight isin lbs, that must be converted to Kg first.100 units x 70 Kg = 7,000 units/hr2.

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/hrx 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 multiplyby 60 minutes to get the hourly dose.

20mcg x 40 Kg x 60 minutes = 48,000 mcg/hr3.

Note that the concentration is in mg/ml not mcg, so you must convert too btain like units of measure.
100 mg = 1mg x=100,000 mcg/mlx 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 rate50 ml x ml

Practice Exam #7

1. Order: Morphine 5 mg/hr. The syringe is labeled 100 mg/ 100 ml. How fast will theIV 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 patientweighs 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 patientweighs 198 lbs. What is the correct rate in ml/hrs?_____ _____








PRACTICE EXAM #7 ANSWERS
1. 5 mg = 100 mgx ml 100 ml100x = 500 mlx = 500 = 5 ml/hr. rate100
2. a. 50 units x 10 Kg x 60 min = 30,000 units/hrb. 30,000 units = 1000 unitsx ml 1 ml1000x = 30,000 (1)x = 30,000 = 30 ml/hr IV rate1000
3. a. 10 mcg x 23 kg x 60 min = 13,800 mcg/hrb. 13,800 mcg = 1 mgx ml 1 ml

NOTE: You must have like units of 1mg = 1000 mcgc. 13,800 mcg = 1000 mcgx ml 1 ml1000x = 13,800 (1)x = 13,800 = 13.8 ml/round to 14 ml/hr1000

from: nclex-rn