Transcript olsen_ch11_lecture

Medical Dosage Calculation
A Dimensional Analysis Approach
Tenth Edition
CHAPTER
11
Calculating Flow
Rates for Intravenous
Medications
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Directory
• Classroom Response System Questions
• Lecture Note Presentation
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Classroom Response
System Questions
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1
The medication order states that 12,000
units of heparin are to be added to 250
milliliters of 5% D/W. The patient is to
receive 1200 units per hour IV. How many
milliliters per hour will your patient receive?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1 Choices
1.
2.
3.
4.
25 mL/hr
22 mL/hr
2.2 mL/hr
2.5 mL/hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #1 Response
1.
2.
3.
4.
25 mL/hr
22 mL/hr
2.2 mL/hr
2.5 mL/hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2
The prescriber has ordered 1000 milliliters of
NS with an addition of 200 units of regular
insulin IV. Infuse at a rate of 2.5 milliliters
per minute. How many hours will it take to
complete this infusion?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2 Choices
1.
2.
3.
4.
5 hr 30 min
2 hr 20 min
5 hr 40 min
6 hr 40 min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #2 Response
1.
2.
3.
4.
5 hr 30 min
2 hr 20 min
5 hr 40 min
6 hr 40 min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3
The prescriber ordered: morphine sulfate
100 mg in 100 mL 5% D/W, IVPB. Infuse at
a rate of 0.005 g/hr. How many milliliters will
the patient receive per hour?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3 Choices
1.
2.
3.
4.
2 mL/1 hr
5 mL/1 hr
4 mL/5 hr
2 mL/5 hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #3 Response
1.
2.
3.
4.
2 mL/1 hr
5 mL/1 hr
4 mL/5 hr
2 mL/5 hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4
The prescriber ordered: 250 mL 5% D/W
with 25,000 units of heparin, infuse at 1500
units/hour IVPB. Calculate the flow rate in
minutes per hour.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4 Choices
1.
2.
3.
4.
10 mL/hr
15 mL/hr
20 mL/hr
25 mL/hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #4 Response
1.
2.
3.
4.
10 mL/hr
15 mL/hr
20 mL/hr
25 mL/hr
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5
The prescriber ordered 3g Timentin
(Ticarcillin disodium) IVPB in 100 mL D5W
infuse in 60 minutes. Calculate the flow rate
in drops per minute if the drop factor is 15
gtt/mL.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5 Choices
1.
2.
3.
4.
10 gtt/min
0.25 gtt/min
0.10 gtt/min
25 gtt/min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Question #5 Response
1.
2.
3.
4.
10 gtt/min
0.25 gtt/min
0.10 gtt/min
25 gtt/min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Lecture Note Presentation
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Learning Outcomes
1. Convert from dosage rates (drug/time) to
IV rates (volume/time).
2. Convert from IV rates (volume/time) to
dosage rates (drug/time).
3. Calculate infusion rates when medication
must be added to an IVPB bag.
4. Calculate infusion rates based on the
size (weight or BSA) of the patient.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Learning Outcomes
5. Calculate flow rates for IV push
medications.
6. Calculate the duration of an IVPB
infusion.
7. Calculate flow rates for medication
requiring titration.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Intravenous Piggyback Infusions
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Figure 11.1 Primary and secondary (IVPB) infusion setup.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Figure 11.2 Packages of secondary IV tubing: (a) 60 drops per mL, (b) 10 drops per mL. (Courtesy of Baxter
Healthcare Corporation. All rights reserved. Photos by Al Dodge.)
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Figure 11.2 (continued) Packages of secondary IV tubing: (a) 60 drops per mL, (b) 10 drops per mL. (Courtesy of
Baxter Healthcare Corporation. All rights reserved. Photos by Al Dodge.)
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Converting Flow Rate to
Dosage Rate
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.1
• An IV is infusing at 100 mL/h. The strength of
the solution is 200 mg in 500 mL. Find the
dosage rate in mg/h.
• Convert 100 mL/h to mg/h using the strength of
the solution as the unit fraction.
100 mL
mg
?
h
h
20
100 mL 200 mg


h
500 mL
mg
40
h
1
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.2
• The patient is receiving 10 mg/min through an
IVPB. The solution has a strength of 400 mg
per100 mL. Find the flow rate in mL/h.
• Convert mg/min to mL/h using the strength of
the solution as the unit fraction.
15
10 mg
mL
?
min
h
10 mg 60 min 100 mL
mL

 150

400 mg
h
min
1h
1
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Calculating Dosage Rates Based on
the Size of the Patient
• A medication order might include the
compound rate:
“2 mg/kg/min.”
• This means that each minute the patient is
to receive 2 milligrams of the drug for
every kilogram of body weight. For
computational purposes this is written as
2 mg
kg  min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.3
• The prescriber ordered:
250 mL 5% D/W with 9 mg Aredia,
0.001 mg/kg/min IV stat.
• The patient weighs 80 kilograms, and the
drop factor is 20 drops per milliliter.
Calculate the flow rate in gtt/min.
•
•
•
•
Patient’s weight: 80 kg.
Order: 0.001 mg/kg/min.
Solution strength: 9 mg = 250 mL.
Drop factor: 20 gtt = 1 mL.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.3 (continued)
• Size of the Patient X Compound Order =
Dosage Rate
80 kg 000.1 mg
gtt

?
1
kg  min
min
gtt
80 kg 000.1 mg 250 mL 20 gtt

44.3



min
1
kg  min
1 mL
9 mg
gtt
 44
min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
IV Push
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.4
• 500 mg of a drug is ordered IVP over 2
min. The concentration of the drug is 100
mg/mL. How many mL will you
administer? Determine the number of mL
you will push during each 30-second
interval.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.4
a) Convert 500 mg to mL using the strength
as the unit fraction.
500 mg
mL
= 5 mL

1
100 mg
b) Convert 30 sec to mL using the rate of
500 mg/2 min.
30 sec = ? mL
1
30 sec 1 min 500 mg
1 mL



 1.3 mL
1
60 sec 2 min
100 mg
2
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Adding Drug to an IVPB
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.5
• A patient must receive 300 mg of a drug
IVPB in 100 mL NS over 60 minutes.
• How many mL must be added to the IV
bag if the vial of the drug has strength of
75 mg/mL? At what rate should the pump
be set?
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Example 11.5 (continued)
a) Using the vial strength convert 300 mg to
mL.
4
300 mg 1 mL

 4 mL
1
75 mg
1
b) Add 4 mL of the drug to the 100 mL bag
of NS to yield a total volume of 104 mL.
Because the infusion is over 60 min (1
hour), set the pump at 104 mL/h.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• A secondary line is referred to as an IV
piggyback.
• IV push, or bolus medications can be
injected into a heplock/saline lock or
directly into the vein.
• In a gravity system, the IV bag that is hung
highest will infuse first.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• An order containing mg/kg/min directs that
each minute, the patient must receive the
stated number of milligrams of medication
for each kilogram of the patient’s body
weight.
• For calculation purposes write mg/kg/min
as:
mg
kg  min
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.
Chapter Summary
• When the size of the patient is multiplied
by a compound rate, the dosage rate is
obtained.
• When titrating medications, the dose is
adjusted until the desired therapeutic
effect is achieved.
Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition
June L. Olsen • Anthony P. Giangrasso • Dolores Shrimpton
Copyright ©2012, ©2008 by Pearson Education, Inc.
All rights reserved.