Medical Dosage Calculation Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton CHAPTER Tenth Edition A Dimensional Analysis Approach Calculating Flow Rates for Intravenous Medications 11

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Directory Classroom Response System Questions Lecture Note Presentation

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Classroom Response System Questions

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #1 Choices 1.25 mL/hr 2.22 mL/hr mL/hr mL/hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #1 Response 1.25 mL/hr 2.22 mL/hr mL/hr mL/hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #2 Choices 1.5 hr 30 min 2.2 hr 20 min 3.5 hr 40 min 4.6 hr 40 min

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #2 Response 1.5 hr 30 min 2.2 hr 20 min 3.5 hr 40 min 4.6 hr 40 min

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 The prescriber ordered: morphine sulfate 100 mg in 100 mL 5% D/W, IVPB. Infuse at a rate of g/hr. How many milliliters will the patient receive per hour?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 Choices 1.2 mL/1 hr 2.5 mL/1 hr 3.4 mL/5 hr 4.2 mL/5 hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #3 Response 1.2 mL/1 hr 2.5 mL/1 hr 3.4 mL/5 hr 4.2 mL/5 hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #4 Choices 1.10 mL/hr 2.15 mL/hr 3.20 mL/hr 4.25 mL/hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #4 Response 1.10 mL/hr 2.15 mL/hr 3.20 mL/hr 4.25 mL/hr

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #5 Choices 1.10 gtt/min gtt/min gtt/min 4.25 gtt/min

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Question #5 Response 1.10 gtt/min gtt/min gtt/min 4.25 gtt/min

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Lecture Note Presentation

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Intravenous Piggyback Infusions

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Figure 11.1 Primary and secondary (IVPB) infusion setup.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.)

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.)

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Converting Flow Rate to Dosage Rate

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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. Example

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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. 1 Example

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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 Calculating Dosage Rates Based on the Size of the Patient

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton The prescriber ordered: 250 mL 5% D/W with 9 mg Aredia, 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: mg/kg/min. Solution strength: 9 mg = 250 mL. Drop factor: 20 gtt = 1 mL. Example 11.3

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Size of the Patient X Compound Order = Dosage Rate Example 11.3 (continued)

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton IV Push

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Example 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton a)Convert 500 mg to mL using the strength as the unit fraction. b)Convert 30 sec to mL using the rate of 500 mg/2 min. = 5 mL Example sec = ? mL 2 1

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton Adding Drug to an IVPB

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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?

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton a)Using the vial strength convert 300 mg to mL. 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. 4 mL Example 11.5 (continued) 1 4

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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: Chapter Summary

Copyright ©2012, ©2008 by Pearson Education, Inc. All rights reserved. Medical Dosage Calculations: A Dimensional Analysis Approach, Tenth Edition June L. Olsen Anthony P. Giangrasso Dolores Shrimpton 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.