B1
BAPTIST HEALTH Schools Little Rock
School Of Nursing
NSG 4017: CRITICAL CARE NURSING
DOSAGE CALCULATION FOR CRITICAL CARE NURSING
LECTURE OBJECTIVES:
1.
Perform conversions from one system of measurement to another and within the same system.
2.
Utilized dimensional analysis and step by step formulas to calculate medication dosages.
3.
Calculate IV flow rates in ml per hour and gtts per minute.
4.
Calculate dosages of medication administered mcg/kg/min, mcg/min, mg/min, mg/hr, and u/hr.
5.
Explain titration.
READING ASSIGNM ENT:
Curren, Chapter 11and 15 - 18
LECTURE OUTLINE:
I.
Common Equvalents/Conversions
A.
Standard tubing drop factor (15 gtt/ml)
B.
Micro tubing drop factor (60 gtt/ml)
C.
Gram (gm) to milligrams (mg)
D.
Milligrams (mg) to micrograms (mcg)
E.
Liter (L) to milliliters (ml)
F.
Kilogram (Kg) to pounds (lb)
II.
IV medications calculated mcg/kg/min
A.
Brevibloc
B.
Dobutrex
C.
Dopamine
D.
Diprivan
E.
Inocor
F.
Nipride
G.
Primacor
III.
IV medications calculated mcg/min
A.
Epinephrine
B.
Isuprel
C.
Levophed
D.
Neosynephrine
E.
Nitroglycerine
IV.
IV medications calculated mg/min
A.
Aminophylline
B.
Amiodarone
B2
C.
D.
E.
Bretylol
Lidocaine
Pronestyl
V.
IV medications calculated mg/hr
A.
Cardizem
VI.
IV medications calculated u/hr
A.
Heparin
B.
Insulin
Rules for Dimensional Analysis
1.
First ask yourself, “W hat is this question asking me?” Determine what units the final answer will be in.
This may be gtt/min or gtt , ml/hr or ml , etc
min
hr
2.
Once you determine what unit you are looking for, write that down first to the left of your problem.
3.
Always start your problem with the unit of measure that you are trying to calculate. If you are looking for
gtt/min, the numerator of the problem should start with gtt.
4.
The unit of measure in each numerator should be the same as the unit of measure in the previous
denominator.
5.
W hen setting up the problem, include all units of measure. This is important, because all the units of
measure must cancel out except the one you are trying to calculate.
6.
W hen a microdrip (60 gtt/ml) set is used, the flow rate in gtt/min is identical to the volume in ml/hr.
Rounding rules
1.
Carry numbers one decimal place beyond where you want to round. If that extra place has a number of 5 or
greater, then you round up. If it is less than 5, then you round down.
2.
Round kilograms to the nearest tenth (one decimal place).
3.
Drops (gtt) must be expressed as whole numbers.
4.
Answers in ml must be expressed to the nearest tenth. This includes your constant when calculating
mcg/kg/min.
5.
Exception to the above rules: If your answer is less than 1, then carry it out to the thousandth place (three
places beyond the decimal point and round back to the hundredth place (two places beyond the decimal).
B3
BAPTIST HEALTH Schools Little Rock
School Of Nursing
NSG 4017: CRITICAL CARE NURSING
STANDARD DRIPS FOR CRITICAL CARE AREAS (BHMC)
•
Amiodarone (Cordarone) 450 mg in D5W 250 ml *Glass*
•
Ativan (Lorazapam) 12 mg in D5W 97 ml *Glass*
•
Bretylol (Bretylium) 2 GM in D5W 500 ml
•
Brevibloc (Esmolol) 2500 mg in D5W 250 ml
•
Cardizem (Diltizem) 100 mg in NS 100 ml
•
Diprivan (Propofol)1 GM in lipids 100 ml
•
Dobutrex (Dobutamine) 500 mg in D5W 250 ml
Double strength - 1000 mg in D5W 250 ml
•
Dopamine 400 mg in D5W 250 ml
•
Epinephrine 4 mg in D5W 250 ml
•
Heparin 25, 000 units in D5W 250 ml
•
Inocor 200 mg (40 ml) in NS 40 ml
•
Insulin (Human-R) 100 units in NS 100 ml
•
Isuprel (Isoproterenol) 1 mg in D5W 250 ml
•
Labetalol 200 mg in D5W 200 ml
•
Levophed (Norepinephrine) 4 mg in D5W 250 ml
•
Lidocaine 2 GM in D5W 500 ml
•
Natrecor (Nesiritide) 2 mg in D5W 500 ml
•
Neo-synephrine (Phenylephrine) 40 mg in D5W 250 ml
•
Nicardipine (Cardene) 100 mg in D5W 250 ml
•
Nipride (Nitroprusside) 50 mg in D5W 250 ml (Advantage)
•
Nitroglycerine (TNG) 50 mg in D5W 500 ml *Glass*
•
Primacor (Milrinone) 20 mg in D5W 100 ml
•
Pronestyl (Procainamide) 2 GM in D5W 500 ml
B4
HELPFUL FORM ULAS (STEP BY STEP)
1. Calculations for M edications Administer mcg/kg/min
A.
# ml of solution x 60 min x pt wt in kg = ___ml
mcg in solution
that # of ml’s = 1 mcg/kg/min (constant)
Example:
Patient weighs 60 kg and is receiving Dopamine with a concentration of 400 mg in 250ml D5W . How many ml = 1
mcg/kg/min? (In other words, what is your constant for this patient of Dopamine at this concentration?)
250 ml x 60 min x 60kg = 2.25 ml
400,000 mcg
2.3 ml = 1 mcg/kg/min (this is your constant)
B. To determine # of mcg/kg/min of medication infusing via pump:
ml rate on pump = ____mcg/kg/min
constant
Example:
Patient weighs 60 kg and is receiving Dopamine with a concentration of 400 mg in 250 ml D5W . Dopamine is
infusing via the pump at a rate of 18 ml per hour. How many mcg/kg/min is this?
250ml x 60 min x 60 kg = 2.25 ml
400, 000 mcg
2.3 ml = 1 mcg/kg/min (constant)
18ml/hr = 7.8 mcg/kg/min
2.3
C. To determine #ml/hr to set pump in order to infuse a certain number of mcg/kg/min:
constant x mcg/kg/min = ml/hr
Example:
Patient weighs 60 kg and is to receive Dopamine at a rate of 8 mcg/kg/min. The Dopamine concentration is 400 mg
in 250 ml D5W . At how many cc/hr would you set the pump to deliver this amount?
250 ml x 60 min x 60 kg = 2.25 ml
400,000 mcg
2.3 ml x 8 mcg/kg/min = 18.4 ml/hr
2.3 ml = 1 mcg/kg/min (constant)
B5
BAPTIST HEALTH Schools Little Rock
School Of Nursing
NSG 4017: CRITICAL CARE NURSING
STUDY GUIDE: DOSAGE CALCULATION
Stacy Palmer, MS, RN
Directions: Calculate each dosage problem and show your work.
1.
The patient has a heparin drip of 25,000 units in 250 ml D5W in fusing at 10 ml/hr. Calculate the
units/hour.
2.
The patient has a heparin drip of 25,000 units in 500 ml D5W infusing as 800 units/hour. Calculate the
ml/hr.
3.
Neo-synepherine 40 mg in 250 ml D5W is used to infuse a dose of 40 mcg/min. Calculate the flow rate in
ml/hr.
4.
The patient is to receive a Lidocaine drip mixed 2 grams in 500 ml D5W at a rate of 2 mg/min. Using a
microdrip tubing, calculate the flow rate in gtt/min.
5.
A patient is on a Lidocaine drip at 45 ml/hr. The Lidocaine drip is mixed 2 grams in 500 ml D5W .
Calculate the mg/min it’s infusing at.
6.
One liter of NS is to infuse over 12 hours. Using microdrip tubing, calculate the number of gtt/min it is to
run.
7.
A patient weighs 80 kg is to receive Dopamine 400 mg in 250 ml of D5W at 10 mcg/kg/min. Calculate the
ml/hr you would set the pump at.
B6
8.
The patient in the above problem (# 7) remains on 10 mcg/kg/min of Dopamine, but the physician
prescribes the Dopamine in double strength. Calculate the ml/hr the pump would be set at.
9.
1000 ml of D5W is to infuse over 8 hours. Using standard tubing, calculate the flow rate in gtt/min and
ml/hr.
10.
A patient is on Nipride 50 mg in 250 ml D5W at 9 ml/hr. This patient weighs 175 lbs. How many
mcg/kg/min is the patient receiving?
11.
A patient weighing 77.9 kg is to receive Esmolol 80 mcg/kg/min. The solution strength is 2500 mg in 250
ml D5W . Calculate the ml/hr flow rate.
12.
Infuse 500 ml of intralipids IV in 6 hours. Set calibration is 10 gtt/ml. Calculate the flow rate in gtt/min.
13.
Dopamine 400 mg in 250 ml D5W is infusing at a rate of 15 ml/hr on a patient weighing 95.9 kg. Calculate
the mcg/kg/min infusing.
14.
A solution of Cardizem 100 mg in 100 ml NS is infusing at 5 ml/hr. Calculate the mg/hr infusing.
15.
A patient is on Diprivan 10 mg/ml in 100 ml lipid solution. 25 ml/hr is the flow rate on this patient
weighing 71.5 kg. Calculate the mcg/kg/min.
16.
B7
The patient in the above problem, #15, needs more sedation. The flow rate of the Diprivan is titrated up by
10 ml/hr. Recalculate the dosage in mcg/kg/min.
17.
Calculate the flow rate in ml/hr for Isuprel infusing at 4 mcg/min from a solution mixed 250 ml D5W with 1
mg Isuprel.
18.
A solution of 500 ml D5NS with 30,000 units heparin is infusing at 25 ml/hr. Calculate the dosage per
hour.
19.
A patient has a Dobutrex drip, 500 mg in 250 ml D5W , infusing at 4 mcg/kg/min. The patient weighs 65.5
kg. Find the flow rate in ml/hr using the pump.
20.
A patient weighing 179 lbs is to be started on Primacor at 0.5 mcg/kg/min. The primacor is mixed 20 mg in
100 ml of D5W . Calculate the flow rate in ml/hr.