Dosage and Calculation

Transcription

1 Dosage and Calculation Module for OB & Pedi TABLE OF CONTENTS: PAGE I. Abbreviation 2 II. Systems of Measurement 3 III. IV Calculations a. Flowrates 7 b. Hourly dosage 7-8 c. Hourly rate (Flowrates) 7-8 IV. OB Calculation Practice 9-11 V. Pediatric Calculation a. Weight Based 14 b. Body Surface Area (BSA) 16 c. Pediatric IVP Medication 23 VI. Reference 26 1

2 Module 1: Abbreviation Objective: Use abbreviations for the times and routes of drug administration as well as metric, apothecary and household abbreviations and abbreviations for drug preparation. Abbreviations of times of medications: ABBREVIATION ac pc Daily bid tid qid qh at bedtime stat q2h q3h q4h prn MEANING Before meals After meals Every day Twice a day Three times a day Four times a day Every hour At hour of sleep immediately every 2 hours every 3 hours every 4 hours if needed Abbreviations for route of medications: ABBREVIATION HHN IM IV IVP IVF IVPB MEANING Hand-held nebulizer Intramuscularly Intravenously Intravenous Push Intravenous Fluid Intravenous Piggyback 2

3 po (PO) PR (pr) SL Subcut Top od os ou By mouth Per rectum Sublingual Subcutaneous Topical Right eye Left eye Both eyes OFFICIAL DO NOT USE LIST Do Not Use Potential Problem Use Instead U, u (unit) Mistaken for 0 (zero), the Write "unit" number 4 (four) or cc Mistaken for IV (intravenous) or the number 10 (ten) Mistaken for each other IU (International Unit) Period after the Q mistaken for "I" and the "O" mistaken for "I Decimal point is missed Write "International Unit" Q.D., QD, q.d., qd (daily) Can mean morphine sulfate or magnesium sulfate Write "daily" Write "every other day" Q.O.D., QOD, q.o.d, qod (every other day) Trailing zero (X.0 mg)* Lack of leading zero (.X mg) MS Confused for one another Write X mg Write 0.X mg Write "morphine sulfate" Write "magnesium sulfate" 3

4 Module 2: Systems of Measurement Units of Measures c = cup cm = centimeters ft = foot g = grams gr = grains gt = drop gtt = drops in = inches kg = kilograms L = liters lb = pound m = meters mcg = micrograms meq = milliequivalents mg = milligrams ml = milliliters mm = millimeters oz = ounce pt = pint qt = quart Tbsp./T = tablespoons tsp./t = teaspoons Decimal Place Values Whole numbers & decimal fractions T h o u s a n d s H u n d r e d s T e n s O n e s d e c i m a l Tenths = first decimal number Hundredths = second decimal number Thousandths = third decimal number *No commas on thousands. *Fractions = reduce to the smallest term. *Mixed number = combination of a whole number and a fraction. p o i n t T e n t h s H u n d r e d t h s T h o u s a n d t h s Equivalents 1 g = 1000 mg 1 mg = 1000 mcg or 0.001g 1 mcg = g 1 gr = 60 mg 1 t = 5 ml 1 T = 3 tsp./t or 15 ml 1 oz. = 30 ml 1 c = 8 oz. or 240 ml 1 L = 1000 ml 1 pt = 500 ml or 16 fl oz 1 kg = 2.2 lbs. 1 kg = 1000 g 1 lb = 16 oz 1 in = 2.54 cm or 25.4 mm 1 unit = 1000 milliunits *Write zero before a decimal point when the dose is less than a whole number. Example = 0.5 ml *Do not use a decimal point or zero after a whole number. Example = 1.0 tab *Conversions factor refer to Booth 4e, Ch.6 *To convert: kg to lb = multiply (K L M) lb to kg = divide * Fahrenheit to Celsius: F 32_ = C 1.8 (big # to small # = minus then divide) *Celsius to Fahrenheit: (1.8 x C) + 32 = F (small # to big # = multiply and add) *Conventional Time to Military Time or International Time/ 24 hr time; Ex. 8:00 am = :00 pm = :00 am = 0000 or :00 am =

5 Important Points: 1. Always place a zero before the decimal point when the quantity is less than a whole number. Example: 0.5 is Correct.5 is WRONG Never place a 0 at the end / No trailing zero. Example: 1.5 is Correct 1.50 is WRONG 2. Rounding Rules: Rounding to whole number: Example: 1.8 = = = 1 Rounding to first decimal number: Example: 1.25 = = = 0.5 Rounding to second decimal number: Example: = = = 1.26 Rounding to third decimal number: Example: = = = If medication is in ml, it is expressed in numbers. Example: 1.5 ml is Correct 1 ½ ml is WRONG OR 0.5 ml is CORRECT ½ ml is WRONG 5

6 4. If medication are household measurements e.g. cups, Tsp, Tbsp, it is expressed in fractions. Example: 1 ½ tsp is Correct 1.5 tsp is WRONG 5. Tablets are expressed in fractions. Example: 1 ½ tablets Correct 1.5 tablets WRONG If tablet is NOT scored, the medication cannot be cut. 6. Capsules, EC, XL, LA, etc medications CANNOT be scored or crushed. Parenteral doses for children are generally NOT rounded, but are left at the first decimal number (tenths) or the second decimal number (hundredths). 7. DO NOT round ADULT weights. 8. Pediatric weights: follow rounding rule as explained in Pediatric section. 6

7 Flowrates and Hourly Dosage / Hourly Rates I. Infusion Rate or Flow Rate: Round IV to nearest whole number. Expressed in ml/hour if infusing via IV pump Expressed in gtts/min if manually infusing IV tubing place an important role in calculating Macrodrip Larger drops Infusion Rate 80 ml/hr or more Drop factors/calibration factor of IV tubing: o 10 gtts/ml o 15 gtts/ml o 20 gtts/ml Microdrip Smaller drips Infusion rates less than 80mL/hr or KVO Pediatric and Critical Care IV Drop factor/calibration factor of IV tubing: o 60 gtts/ml II. Dimensional Analysis: a. Normal Saline 1 L to run over 10 hours. Drop factor: 15 gtts/ml. What is the Flowrate? a. gtts/min = 15 gtts x 1000 ml x 1 h = 25 gtts/min ml 10 h 60 min b. ml/h = 1000 ml = 100 ml/h 10 h b. Vancomycin 1 gram IVPB in 250 ml of NS to run over 90 minutes. Drop factor: 20 gtts/ml. What is the flowrate? a. gtts/min = 20 gtts x 250 ml = = 56 gtts/min ml 90 min 7

8 b. ml/h = 250 ml x 60 min = = 167 ml/h 90 min 1 h c. IV order: 1000 ml D5/W q8 hours. Set calibration is 15 gtts/ml. 1. gtts/min = 31 gtts/min 1000mL x 1 hr x 15 gtts = = 31 gtts/min 8 hrs 60 min ml 2. ml/h = 125 ml/h 1000 ml = 125 ml/h 8 h Computing hourly rate of medication is the same as computing flow rates. 1. Heparin 25,000 units/250 ml D5W. Order: Heparin 1450 units/hour on pump. What is the flow rate ml/h? 250 ml x 1450 units = 14.5 = 15 ml/h units h 2. Order: Aminophylline 500 mg in 500 ml of D5W to infuse at 40 ml/hr. What is the hourly dose? mg/hr 500 mg x 40 ml = 40 mg/h 500 ml h 3. IV order: 1000 ml D5/1/2NS with 40 meq of KCl to run for 10 hours. Set calibration is 60 gtts/ml. How many meq of KCl/h will infuse? (meq/h) 40 meq_ = 4 meq/h 10 h 8

9 OB Calculation Practice OB calculation is the same as adult calculation. Apply the rule for rounding when necessary. Round up or down IV flow rates (ml/hr or gtt/min) to a whole number. 1. The physician ordered the Pitocin infusion to run at 6 mu/min. The pharmacy sent up 10 units of Pitocin in 1000mL of Lactated Ringers (LR). You would set your pump at ml/hour. 2. Magnesium sulfate 20 grams is mixed in 500 ml Lactated Ringers. Order: infuse a maintenance dose of magnesium 2 grams/hour. How many ml/hr will the IV run? ml/h 3. The nurse notes the patient s IV pump is set at 12ml/hr. The IV bag holds 20 units of Pitocin mixed in 1000ml of Lactated Ringers. How many mu/min is the client receiving? mu/min 4. The order reads: begin the infusion of Pitocin at 8mU/min. On hand - 20 units of Pitocin mixed in 1000 ml of Lactated Ringers. How will you set the pump? ml/h 5. The order reads: begin a Pitocin 4mU/min. You have on hand Pitocin 20 units in 1000ml of Lactated Ringers. How should you set the pump? ml/h 9

10 6. You have on hand Magnesium Sulfate 20 grams in 500ml of Lactated Ringers. The order is to infuse a maintenance dose of Magnesium 1 gram/hour. How many ml/hr will you run the IV? ml/hr 7. A client is admitted to the labor unit with BP 160/110 mm Hg. The health care provider orders an infusion of 6 grams of Magnesium Sulfate in 30 minutes as a loading dose via infusion pump. On hand: Magnesium Sulfate 40 grams in 1000 ml Lactated Ringers. What is flow rate for the loading dose of 6 grams/hour? ml/hr. 8. A client is admitted to the labor unit with BP 170/110 mm Hg. The health care provider orders an infusion of 4 grams of Magnesium Sulfate in 30 minutes as a loading dose via infusion pump. On hand: Magnesium Sulfate 20 grams in 500 ml Lactated Ringers. What is flow rate for the loading dose of 4 grams/hour? ml/hr. 9. The health care provider (HCP) orders Cytotec 50 micrograms (mcg) intra-vaginally initially for induction of labor, then repeat at intervals not to exceed every 3-6hr. Available: Cytotec 100-mcg tablet. Administer: tablet(s) 10. The nurse notes the patient s IV pump is set at 18 ml/hr. The IV bag holds 20 units of Pitocin mixed in 1000ml of Lactated Ringers. How many mu/min is the patient receiving at this time? mu/min 11. Administer a dose of Vitamin K (Aquamephyton) 0.5mg. Available: Vitamin K 1mg/1ml. How many mls would you administer? ml (round to first decimal number) 10

11 12. The HCP orders regular insulin IV, 10 units/ hour via infusion pump to a client who is in labor. On hand: 100 units of regular insulin in 250mL Normal Saline. What is the infusion rate per hour? ml/hr 13. The client has been diagnosed with deep vein thrombosis (DVT) and the HCP orders Heparin 5000 units per hour. Available: Heparin 40,000U/1000mL of LR. How many ml per hour would you set your IV pump to infuse? ml/hr 14. The HCP orders Morphine Sulfate 1 mg IV q 4 hours prn pain. Stock: 4 mg/ml vial. How many ml will you give? ml (round to second decimal number) 15. The HCP orders Betamethasone 12 milligrams (mg) intramuscular times 2 doses 24 hours apart for preterm labor. Available: Betamethasone 30mg/5ml. Administer: ml(s). (round to first decimal number) 11

12 Pediatric Calculation Pediatric drug dosages are usually less than adult dosages. Smaller dosages are required for infants and children because of the immaturity of their body systems to metabolize drugs and their smaller size, weight, and body surface area. Exact and careful calculations are required for safe and therapeutic doses for pediatric clients. Small dosages may be ordered; small discrepancies may be dangerous. Reminders: 1. Weight Conversions: Pediatric weight must be converted to kilogram (ounces / pounds). Pediatric weights will be rounded to second decimal number. Example: 1. Newborn (neonate) and some infant weights are measured in grams. a) A neonate weighs 2300 g. Convert to kilograms Kg = 2300 g/1 x 1 kg/1000 g = 2.3 kg b) A newborn weighs 4630 g at birth. Convert to kilograms Kg = 4630 g/1 x 1 Kg/1000 g = Kg = 4.63 kg (rounded to 2 nd decimal number) 2. Child weighs 16 lb 10 oz. Convert to Kg a) 3 steps: 1. Convert ounce to pounds lb = 10 oz/1 x 1 lb/ 16 oz = lb 2. Add the total weight in pounds 16 lb lb = lb 3. Convert to kg Kg = lb/1 x kg/2.2 lb = kg = 7.56 kg (round to the 2 nd decimal number) 12

13 2. The maximum volume of a parenteral injection in children is generally 1 ml. For subcutaneous route, 0.5 ml is the maximum volume, and for intradermal route, 0.01 to 0.1 ml is the maximum volume of the injection. 3. Pediatric Injections are calculated to the second decimal number and are often administered using a 1-mL precision syringe (tuberculin syringe). 4. The smallest possible amount of diluent is added to dilute IV medications for pediatric patient. 5. To be safe in calculation, use calculator and double-or triple- check your answer! 13

14 Steps and Rule mg/kg Body Weight 1. Convert weight to kilograms. (Round to the second decimal number) 2. Determine the safe dose range in milligrams per kilogram. 3. Decide whether the ordered dose is safe by comparing the order with the safe dose range listed in the reference. 4. Calculate the dose needed. Example: Amoxicillin/Clavulanate Potassium (Augmentin) 150 mg po q 8h is ordered for a child weighing 33 lb. The accompanying information states that Children 40 kg receive 6.7 to 13.3 mg/kg q8h. 1. Convert weight to kg: Kg = 33 lb x 1 kg/2.2 lb = 15 kg 2. Determine safe dose range: Low dose: 15 kg x 6.7 mg /kg = mg High dose: 15 kg x 13.3 mg/kg = mg 3. Is the dose safe? YES. (150 mg q 8h is within the dose range) 4. Calculate the dose: ml = 150 mg/1 x 5 ml/125 mg = 6 ml 14

15 A child weighs 18 kg and has an order for phenytoin sodium 30 mg po every 8 hours. The recommended dosage is 5 mg/kg/day. 1. Convert weight to kg: Kg = 18 Kg 2. Determine safe dose range: 18 Kg x 5 mg/kg/ day = 90 mg / day 90 mg / 3 doses/day = 30 mg/dose 3. Is the dose safe? YES. (30 mg q 8h is within the dose range) 4. Calculate the dose: ml = 30 mg/1 x 5 ml/125 mg = 1.2 ml 15

16 Steps and Rule m 2 Medication Orders 1. Find the body surface area (BSA) in meters squared (m²). If you know the height in cm and weight on Kilograms, calculate: BSA = Example: Find the BSA for a child who is 85 cm tall and weighs 13.9 Kg. BSA = 85 x 13.9 m² = = m² = 0.57 m² Example: Find BSA for a baby who is 24 inches tall and weighs 12 lb 4 oz Convert ounces to pounds: lb = 4 oz/1 x 1 lb/16 oz = 0.25 lb + 12 lb = lbs Convert pounds to kg: Kg = lb/1 x 1 kg/ 2.2 lb = kg Convert inches to cm: Cm = 24 inches/1 x 2.54 cm/ 1inch = cm BSA = x m² = = m² = 0.31 m² Average BSA for neonates: 0.25 m 2 Average BSA for 2 years old: 0.5 m 2 Average BSA for children (9 years): 1.07 m 2 Average BSA for children (10 years): 1.14 m 2 Average BSA for children (12-13 years): 1.33 m 2 2. Determine the safe dose using a reference. 3. Decide whether the ordered dose is safe. 4. Calculate the dose needed. 16

17 Example: A 2-year-old child with a weight of 27 lb 12 oz and height of 35 inches is prescribed Leucovorin Calcium 5.6 mg po q6h x 72 hours. Literature states dose for rescue after methotrexate therapy is 10 mg/m²/dose q6h x 72 hours. Supply: 1 mg/ml reconstituted by the pharmacy. 1. Find the body surface area (BSA) in meters squared. Convert ounces to pounds: lb = 12 oz/1 x 1 lb/16 oz = 0.75 lb + 27 lb = lb Convert pounds to kg: Kg = lb/1 x 1 kg/2.2 lb = kg Convert inches to cm: Cm = 35 inches/1 x 2.54 cm/1 inch = 88.9 cm BSA = 88.9 x m² = = m² = 0.56 m² Determine the safe dose using a reference. mg = 10 mg x 0.56 m² = 5.6 mg / dose 3. Decide whether the ordered dose is safe. Prescribed dose Leucovorin Calcium is 5.6 mg po q6h = YES it is safe. 4. Calculate the dose needed. ml= 5.6 mg/1 x 1 ml/1 mg = 5.6 ml / dose 17

18 Example: A child is ordered an infusion of cytarabine 200 mg/m2 in 0.9% NaCl to infuse over 24 hours. If the child weighs 22.7 kg and is 120 cm, how many mg of cytarabine would you add to the 9% NaCl? mg 1. Find the body surface area (BSA) in meters squared. BSA = 120 x 22.7 m² = 2724 = m² = 0.87 m² Calculate the dose needed. mg= 200 mg x 0.87 m² = 174 ml 18

19 Practice 1. Ceclor 45 mg/kg/day p.o. in 3 divided doses is ordered for a child who weighs 66 lbs. A 75 ml stock medication is labeled Ceclor 125mg/mL. How many ml would the nurse administer per dose? (Round to the first decimal number) 2. Ampicillin 250 mg IV every 6 hours is ordered for a child weighing 10.7 kilograms. The safe dose range of ampicillin is mg/kg/day in 4 divided doses. a. What is the safe daily dosage range for this child? mg/day (Round to the first decimal number) b. What is the safe individual dosage range for this child? mg/dose (Round to first decimal number) c. Is the ordered dose safe? YES NO If No, Specify: TOO HIGH or TOO LOW 3. The HCP orders Cipro 300 mg q12 h po for a child weighing 66.6 lbs. You have Cipro 250 mg/5 ml. The recommended oral dosage is mg/kg/day every 12 hours. a. Child s weight is kg. b. What is the safe and therapeutic daily dosage range for this child? c. What is the safe individual dose range for this child? d. Is the dose safe? YES NO IF NO, Specify: Too High or Too LOW e. How many mls are needed to administer the ordered dose? 19

20 4. The HCP orders Keflex 250 mg po four times a day for a child weighing 50 lb. You have Keflex 250 mg capsules. The recommended daily po dosage for a child is 25 to 50 mg/kg/day in divided doses q6 h. a. Child s weight is kg. b. What is the safe individual dosage range for this child? c. Is the order safe? Yes NO If NO, Specify: Too HIGH or Too LOW d. How many capsule(s) will you administer? 5. The HCP orders Lanoxin 1.25 mg po daily for an infant weighing 6 lb 8 oz. You have Lanoxin 0.05 mg/ml. The recommended daily dosage for an infant is to 0.06 mg/kg/day in divided doses two times a day. a. Child s weight is kg. b. What is the safe individual dosage range for this child? mg c. Is the order safe? YES NO If NO, Specify: Too HIGH or Too LOW d. How many milliliters will you administer? ml 20

21 6. The HCP orders Orapred 45 mg twice a day po for an asthmatic child weighing 94 lb. You have Orapred 15 mg/5 ml. The recommended oral dosage is 0.5 to 2 mg/kg/24 h divided twice a day. Maximum dosage is not to exceed 80 mg/24 h. a. Child s weight is kg. b. What is the safe daily dosage range for this child? c. What is the safe individual dosage for this child? d. Is the order safe? YES NO If NO, Specify: Too HIGH or Too LOW e. How many milliliters will you administer? ml 7. Tobramycin 100 mg IV q 8 hours is ordered for a child weighing 80 lbs. The safe dose range is mg/kg/day in divided doses q 8 hours. a. Child s weight is kg. b. What is the safe daily dose range? c. What is the safe individual dose range? d. Is the dose safe? YES NO IF NO, Specify: Too High or Too LOW 8. The HCP orders Omnicef 125 mg po bid for 10 days for a child weighing 33 lbs. The safe dosage range is 7 mg/kg q 12 hours. Available as 125mg/5mL. a. What is the weight in kg? Kg b. What is the safe individual dosage range? c. Is the ordered dose safe? YES NO If NO, Specify: Too HIGH or Too LOW d. How many milliliters will you administer? ml 21

22 9. Aztreonam 1 gram IV every 8 hours is ordered for a 60 lb child. The safe dose for this drug used to treat infection in children with cystic fibrosis is 50 mg/kg every 8 hours. a. What is the weight in kg? b. What is the safe individual dosage range for this child? c. Is the ordered dose safe? YES NO If NO, Specify: Too HIGH or Too LOW 10. The HCP orders Acetaminophen 145 mg q 4 hours prn fever/pain. The child weighs 14.5 kg. The safe dose range for this drug is mg/kg/dose, with a maximum of 5 doses/24 hrs. a. What is the weight in Kg? b. What is the safe individual dose range? c. Is the ordered dose safe? YES NO IF NO, Specify: Too HIGH or Too LOW 22

23 Steps to Solving Parenteral Pediatric IV Push Medications 1. Convert pounds to kilograms. (Round to the second decimal number) 2. Determine the safe dose range in milligrams per kilogram using a drug reference. 3. Decide whether the ordered dose is safe by comparing the order with the safe dose range listed in the reference. 4. Calculate the dose needed. 5. Check the reference for diluent and duration for administration. Example: A child weighs 50.6 lb and has an order for gentamicin 50 mg IV piggyback (IVPB). The recommended dosage for a child is 6 to 7.5 mg/kg/day divided every 8 hours. Is the dosage ordered safe? 1. Convert pounds to kilograms. Convert pounds to kilograms: 50.6 lb = 23 kg 2. Determine the safe dose range in milligrams per kilogram using a drug reference. Low dose: 6 mg 23 = 138 mg per day 3 doses = 46 mg/dose High dose: 7.5 mg 23 = mg per day 3 doses = 57.5 mg/dose 3. Decide whether the ordered dose is safe by comparing the order with the safe dose range listed in the reference. Yes, the dosage is safe. 23

24 More Practice! 1. Rocephin 1 gram IV is ordered before surgery. Concentration is Rocephin 1 gram/100 ml of D5W. Administer over 30 minutes. What is the flow rate? 2. Keflex 250 mg q 6 hrs in 4 divided doses is ordered for a child. The child weighs 42 lbs. The safe dose range is mg/kg/day. a. What is the weight in kg? b. What is the safe daily dosage range? c. What is the safe daily dosage range? d. Is the dose safe? YES NO If NO, Specify: Too HIGH or Too LOW 3. Vancomycin 100 mg IV q 8 hours is ordered. You are to infuse the medication over 2 hours. Your availability is 100 mg/50ml. What is your flow rate? (Round to nearest whole number) 4. The HCP orders gentamycin 80 mg IV for a child weighing 10 kg. The safe dose range is mg/kg/day. a. What is the safe individual dose range? b. Is the dose safe? YES NO If NO, Specify: Too HIGH or To LOW 24

25 5. The recommended dose of mercaptopurine is 2.5 mg/kg/dose p.o. q 8 hours. The recommended individual dosage for a child weighing 44 lb is. 6. Augmentin 175 mg PO q 8 hours is ordered. The child weighs 13.2 kg. The safe dose is mg/kg/day in divided doses every 8 hours. a. What is the safe daily dose range? b. What is the safe individual dose range? c. Is the dose safe? YES NO IF NO, Specify: Too HIGH or Too LOW 7. Vancomycin 400 mg IV q 8 hours is ordered for a 12-yr-old child with CF weighing 66 lbs. The safe dose range is 40 mg/kg/day in divided doses q 8 hours. Availability is Vancomycin 400mg/100 ml of NS. The medication needs to be administered over 90 minutes. a. What is the weight in kg? b. What is the safe daily dose? c. What is the safe individual dose? d. Is the dose safe? Yes NO IF NO, Specify: Too HIGH or Too LOW 8. The HCP orders cephalexin 250 mg every 6 hours for a child weighing lbs. The safe dosage range for cephalexin is mg/kg/day in 4 divided doses. a. What is the weight in kg? b. What is the safe individual dose? c. Is the ordered dose safe? YES NO IF NO, Specify: Too HIGH or Too LOW 25

26 References Booth, K. Whaley, J., Sienkiewicz, S., & Palmunen, J. (2012). Math & Dosage Calculations for Health Care Professionals (4th ed.) Mac-Graw Hill Companies, NY ISBN Broyles, Bonita. (2003) Dosage Calculation Practice for Nurses. Canada: Delmar Thomson Learning. Bucholz, Susan. Henke s Med-Math Dosage Calculation, Practice & Administration. 8 th ed. Wolters Kluwer. Curren, Ana, and Margaret Witt. Curren s Math for Meds. 11th ed. Cengage, n.d. Dosage Calculations Made Incredibly Easy. Springhouse Co. De Castillo Martinez, Sandra Luz, and McCoullough-Werner, Maryanne. Calculating Drug Dosages: An Interactive to Learning Nursing Math. 2 nd ed. F.A. Davis Company, Philadelphia. Facts about the Official Do Not Use List of Abbreviations. Accessed December 8, Giangrasso, Anthony, and Dolores Shrimpton. (2013). Dosage Calculations A Multi-Method Approach. Upper Saddle River, New Jersey: Pearson Education Inc. Kee, Joycee, and Sally Marshall. (2009) Clinical Calculations with Applications to General and Specialty Areas. 6th ed. Saunders Elsevier. Koharchik, Linda, Elaine Hardy, Michalene King, and Yitnalem Garibo. Evidence-Based Approach to Improve Nursing Student Dosage Calculation Proficiency. Teaching and Learning in Nursing 9, no. 2 (April 1, 2014): doi: /j.teln Pickar, Gloria and Abernethy, Amy Pickar (2008). Dosage Calculations. 8th ed. Clifton Park, NY: Thomson Delmar Learning. 26