7 1 Interpreting Labels Label Info 25 mg ml

7. 1 Interpreting Labels Label Info 25 mg/ml Meaning This ratio tells the amount of medication in each ml of solution 1: 4 Ratios written this way always mean grams per milliliter 30% Amount of medication (in grams) in every 100 ml of solution 40 mg = 2 cc Equation tells the amount of medication in the given volume Units per ml (100 units per ml in this case) U-100 20 m. Eq/ml This ratio tells the number of milli-equivalents per milliliter of solution

7. 2 Dosage Calculation for Prepared Solutions • Four ways of calculating solution dosages: 1. Dosage formula 2. DQA (Desired Quantity Available) proportion 3. DHQ (Desired Have Quantity) formula 4. Label proportion

7. 2 Dosage Calculation for Prepared Solutions • Ordered: 15 mg IM q. a. . m. Label info: 20 mg per ml Patient dosage _____ • Using dosage formula : Doctors orders label info = patient dosage

7. 2 Dosage Calculation for Prepared Solutions • Using DQA (Desired Quantity Available) proportion :

7. 2 Dosage Calculation for Prepared Solutions • DHQ (Desired Have Quantity) formula:

7. 2 Dosage Calculation for Prepared Solutions • Label proportion:

7. 3 Dosage Calculations from Medications in Powdered Form • • Medications may be unstable when stored in solution. They are packed in powder or granular form. You will be told: a. Doctor’s orders (charted amount) b. Label information • You will need to calculate: a. How much to give per dose b. How often to give it c. How to relabel the vial if it is multidose

7. 3 Dosage Calculations from Medications in Powdered Form • • Ordered: 250 mg IM q. i. d. Label info: 500 mg medication – inject 1. 2 ml SW to yield 2 ml solution. Must be used within one hour. How much do you give and how often? Using dosage formula

7. 3 Dosage Calculations from Medications in Powdered Form • Complete answer: Give 2 ml IM every 6 hours. Relabel the vial 1. 0 g = 2 ml, with the date and time of preparation, and your initials.

7. 4 Finding the Amount of Medication in a Solution • To determine the amount of pure medication by weight, in a solution with a specified strength, use one of the dosage calculation formulas (section 7. 2) with the medication weight as the unknown.

7. 4 Finding the Amount of Medication in a Solution • How many grams of potassium citrate (crystals) are contained in 50 ml of 7% potassium citrate solution Using dosage formula : Using DQA Proportion

7. 4 Finding the Amount of Medication in a Solution • How many grams of potassium citrate (crystals) are contained in 50 ml of 7% potassium citrate solution Using DHQ formula : Using Label Proportion

7. 5 Diluting Solutions • Inverse Proportion method:

7. 5 Diluting Solutions • Example: How many ml of a 20% solution are needed to prepare 50 ml of a 5% solution? Answer: Take 12. 5 ml of a 20% solution and add 37. 5 ml of sterile water to make 50 ml of 5% solution

7. 5 Diluting Solutions • Dilution equation

7. 5 Diluting Solutions • Example: How many ml of a 20% solution are needed to prepare 50 ml of a 5% solution? Answer: Take 12. 5 ml of a 20% solution and add 37. 5 ml of sterile water to make 50 ml of 5% solution

7. 6 Calculating Pediatric Dosages by Body Weight • To calculate children’s dosage using body weight 1. if the medication is per kg (or lb. ), child’s weight is in kg or lb. ) rounded to tenths 2. Multiply the label my the child’s weight

7. 6 Calculating Pediatric Dosages by Body Weight • Ordered: antibiotic q. 4 h. For a 5 kg infant Label: antibiotic 60 mg/kg/day How many mg per day? How many mg per dose?

7. 7 Dosage Calculation using a Nomogram • • Another way to calculate patient dosage is by finding the patient’s body surface area (BSA) using a nomogram (pg 209) To get BSA read both the height and weight on the left and right scales, then use a straightedge to connect the points and read the BSA from the middle scale Example: Height = 56” and weight = 46 kg, find the patient’s BSA. (Try this now)

7. 7 Dosage Calculation using a Nomogram • • Once you get the BSA, the proportion or factor-label method to get the dosage. In previous example, the BSA = 132 m 2. If the label says what is the patient dosage? Using the proportion method:

7. 7 Dosage Calculation using a Nomogram • Using the factor-label method:

8. 1 Rate of Flow – Formula Method • Formula Method • Factor-Label Method (equivalent)

8. 1 Rate of Flow – Formula Method • Ordered: IV 5% D/W 100 ml/hr. Tubing calibration: 15 gtts. /ml Find the rate of flow using both methods

8. 2 Rate of Flow –Division Factor Method • Division Factor Method

8. 2 Rate of Flow –Division Factor Method • Example: Ordered: IV rate at 200 ml/hr. Drop factor: 15 gtts. /ml What is the flow rate?

8. 3 Total Time • Adjusted formula method • Adjusted factor-label method

8. 3 Total Time • Example: Ordered: 1200 ml IV Drop factor: 15 gtts. /ml Rate of flow: 50 gtts. /min. How long will the IV run?

8. 4 Pediatric IV’s • To calculate flow rate of an IV 1. Read label to get volume that contains the correct dosage 2. Find amount of IV fluid to be added 3. Add diluted volume and flush volume to get total infusion volume 4. Calculate rate of flow

8. 4 Pediatric IV’s • Medication of 50 mg is ordered diluted to 50 ml. Infuse over 30 minutes and follow with a 15 ml flush. The label reads 25 mg/ml. Calculate the amount of IV fluid needed to mix the medication and the flow rate for administration. 1. 2 ml contains 50 mg 2. 50 ml – 2 ml = 48 ml 3. 50 ml + 15 ml = 65 ml total infusion volume 4. Rate of flow

8. 5 Piggyback IV Solutions • IV solutions are frequently ordered to run piggyback with IV fluids (see picture at beginning of this section) When the piggyback is running, the main IV bag is either clamped shut or hung down lower than the piggyback to allow the secondary fluid to infuse

8. 5 Piggyback IV Solutions • To calculate rate of flow for the piggyback and the IV between piggybacks: 1. Calculate the rate of flow for each piggyback 2. Calculate the number of piggybacks to be given. 3. Determine the total time and total fluid volume for all piggybacks.

8. 5 Piggyback IV Solutions • To calculate rate of flow for the piggyback and the IV between piggybacks (continued) 4. Determine the amount of time and volume of fluid remaining. 5. Calculate the rate of flow of the IV between piggybacks, using the amounts from step 4.

8. 5 Piggyback IV Solutions • Ordered: 3000 ml IV fluids in 24 hours Piggyback med. in 100 ml to run 30 min. q. 12 h. Drop factor for all tubing is 15 gtts. per ml 1. Rate of flow: 2. # piggybacks in 24 hours 3. Total time and volume for piggybacks:

8. 5 Piggyback IV Solutions • Ordered: 3000 ml IV fluids in 24 hours Piggyback med. in 100 ml to run 30 min. q. 12 h. Drop factor for all tubing is 15 gtts. per ml 4. Time in minutes and volume in ml remaining: 5. Rate of flow between piggybacks

8. 6 Drug Infusion Rate of Flow • Many critical care medications are added to the IV solution and infused at the rate of a specified concentration of medication per unit of time. This is called drug infusion rate, and is expressed in ml/min. or ml/hr.

8. 6 Drug Infusion Rate of Flow • To calculate the drug infusion rate: a. Determine the solution strength b. Determine what has been ordered c. Calculate the patient dosage, calculate the drug infusion rate in ml/min. d. Calculate the drug infusion rate in ml/hr.

8. 6 Drug Infusion Rate of Flow • Order: ISUPREL 2 mg IV in 500 ml 5% D/W to run at 5 g/min. Calculate the infusion rate in ml/min. and ml/hr. a. solution strength: 2 mg/500 ml b. dosage ordered: 5 g/min c. Calculate the patient dosage, calculate the drug infusion rate in ml/min. d. Calculate the drug infusion rate in ml/hr.

8. 7 Monitoring Flow Rates • No problems from this section.