Transcript IV Calculations

IV Calculations
Heparin, Insulin & other meds
Chapter 17
Concentration
Definition
Concentration = Total Amount of Drug
Total Volume (mL)
Weight over volume: W
V
Problem
• An order is written for 25,000 units of heparin in
250 ml of D5W to infuse at 1000 units/hr, what is
the correct rate of the infusion (in ml/hr)?
• Concentration of IV = 25,000 units of heparin
250 mL D5W
• Concentration of IV = 100 units of heparin/mL
Continued
• IV rate = Dose desired
Concentration of IV
• IV rate = 1000 units/hr
100 units/mL
• IV rate = 10 mL/hr
Problem
• Heparin sodium 25,000 units in 500 ml D5W
and infuse at 2000 units/hr.
How many mL/hr will the pump be set ?
• What is the concentration? 25,000 units
500 mL
• 50 units/mL
• What is the flow rate: 2000 units/h
50 units/mL
• 40mL/h
Problem
• Mr. Collins has an order for 800 units of
heparin sodium per hour. Premixed 1000ml
bags containing 50,000 units of heparin are
available in the pharmacy stock area.
• At what rate will the nurse set the infusion
pump to deliver the dosage?
16 mL/h (concentration is 50 units/mL)
• Mr. Collins' heparin dosage needs to be
changed to 750 units/hr. At what rate will the
nurse set the infusion pump?
15 mL/h
Insulin
• Doctor's order: Regular insulin 7 units/hr
IV
• Available: Regular insulin 50 units in
250 mL NS
• The concentration is ______
0.2 units/mL
• The IV flow rate to deliver this dosage is:
35 mL/h
Insulin
• Doctor's order: Regular insulin 12
units/hr IV
• Available: Regular insulin 50 units in
100 mL NS
• The concentration is _________
0.5 units/mL
• The IV flow rate to deliver this dosage is:
 24 mL/h
Potassium Chloride
• Order: KCl 40 mEq/L D5W to infuse at 2
mEq/h
• What is the concentration? ______
40 mEq/1000 mL = 0.04 mEq/mL
• Rate for infusion pump: _______
50 mL/h______
Magnesium Sulfate
• Order: magnesium sulfate 4 g IV in 500
mL D5W at 500 mg/h on an infusion
pump
• What is the concentration? ___
8 mg/ml_______
• Rate for infusion pump: ______
62.5 mL/h
Dosage Calculation: Lidocaine IVP
• Order: lidocaine 100 mg IVP
•
Available: 2% lidocaine
What is the concentration? _____ mg/mL
 20 mg/ml
How many milliliters will you administer?
 5 mL
Finding Units/h from mL/h
• Concentration: 25,000 units heparin/250 mL
D5W (100 units/mL)
• IV rate: 10 mL/hr
• How many units/h is the patient receiving?
• Set up: 10 mL/hr x 100 units/mL
= 1000 units/h
Finding Units/h from mL/h
• Supply: 25,000 units heparin/250 mL
D5W
• Concentration:100 units/mL
• IV rate: 14 mL/hr
• How many units/h is the patient
receiving?
• Set up: 14 mL/hr x 100 units/mL
1400 units/h
mL/min to mL/h
Round mL/min: <1 hundredths, >1 tenths BEFORE x 60 min/h!
• Order: lidocaine 2 g in 250 mL D5W IV to infuse
at 5 mg/min.
• What is the concentration? __________
 2 g = 2000 mg = 8 mg/mL
250 mL
• What is the flow rate for the infusion pump?
________________________
• 5 mg/min = 0.625 = 0.63 mL/min x 60 min/hr =
8 mg/mL
37.8 mL/h
• Problem: Infuse lidocaine 1 g in D5W 200 mL at
12 mg/min.
• Find the concentration:
1g = 1000 mg = 5 mg/mL
200 mL
• What is the flow rate for the infusion pump?
________________________
• 12 mg/min = 2.4 mL/min x 60 min/hr =144 mL/h
5 mg/mL
Concentration and Volume per Hour and Minute
with a Drug in Micrograms
• Problem: Infuse dobutamine 250 mg in D5W 500
mL at 650 mcg/min. What is the flow rate in
mL/h for the infusion pump?
• Find concentration:
• 250 mg = 250,000 mcg = 500 mcg/mL
500 mL
• What is the flow rate for the infusion pump?
________________________
• 650 mcg/min = 1.3 mL/min x 60 min/hr = 78 mL/h
500 mcg/mL
IV Medication Ordered per Kilogram per
Minute
• Order dopamine 750 mg in 500 mL NS IV to infuse at 15
mcg/kg/min; weight 75 kg
• Find concentration:
• 750 mg = 750,000 mcg = 1500 mcg/mL
500 mL
• What is the order for how much the patient will receive per
min?
• 15 mcg/kg/min x 75 kg = 1125 mcg/min
• What is the flow rate for the infusion pump?
________________________
• 1125 mcg/min = 0.75 mL/min x 60 min/hr = 45 mL/h
• 1500 mcg/mL