NURS 4431 Nursing Care of Children and Adolescents

Math for Pediatric Nursing

A Study Guide

Pediatric Medications & Dosages Math Test

• Your math exam will be given during your clinical orientation/lab day, Week 2 of the course.

• It will be a paper and pencil exam to be graded by the Clinical Instructor.

• The test consists of 30 questions that must be completed in 60 minutes.

Pediatric Medications & Dosages Math Test

• You cannot give medications in Clinical until you pass the math test with a 90% or higher.

• A score of 90% or higher is passing.

• Students have two attempts: Math Test #1 and Math Test #2.

Pediatric Medications & Dosages Math Test

• If you have to take Math Test #2, it will be given the first day of the 2nd week of clinical.

• The score on Math Test #1 counts 10% towards the N4431 course grade.

• If 90% is NOT achieved on Math Test #2, a student must withdraw from N4431.

Key Points

DO NOT PANIC; DO STUDY!

You will be provided a basic calculator to use for the test.

Work practice problems in Pediatric Medications & Dosages Math Study Guide posted on EPIC.

Study this tutorial .

Read in Wong textbook; pp. 1120-1130 on medication administration.

Key Points

Follow Calculation Rules:

• Round all answers to the 2nd decimal. Place 1.2672 is rounded to 1.27

• Round at end of your calculations Round your final answer only.

• If the number is 5 or greater, round off to the next highest number 1.585 = 1.59

IV infusion rates, daily maintenance fluidneeds, and calorie amounts are rounded towhole numbers, not decimals.

Key Points

Joint Commission “Do Not Use” List (1/2004):

• Lead with zero “0” before a decimal point:0.12 mg not .12

• Do not end with zero “0” after a decimal point:1.2 mg not 1.20 mg

• Write unit or units; do not write U or u

• Write international units; do not write IU

• Write daily or every other day; Do not write QD or QOD

• Write morphine sulfate or magnesium sulfate; do not write MS, MSO4, or MgSO4

Key Points

Joint Commission Recommendations (5/2005):

• Write greater than; do not write >

• Write less than; do not write <

• Write ml or milliliters; do not write cc

• Write at; do not write @

• Write mcg or micrograms; do not write µg

• Write names of drug in full: do not abbreviate

• Use metric units: do not use apothecary units

KNOW Essential Equivalents

MOST IMPORTANT IN PEDIATRIC NURSING!

1 kg = 2.2 lbs

You must be able to convert the weight of your patients from kg to lbs and from lbs to kg.

1 in = 2.54 cm

You must be able to convert the height or length of your patients from inches or feet/inches to cm and from cm to inches.

KNOW Essential Equivalents

IMPORTANT for MEASURING FLUIDS AND MEDICATION ADMINISTRATION

1 oz = 30 mL

1 Tbsp = 15 mL

1 tsp = 5 mL

3 tsp = 1 Tbsp

1 cup = 240 mL

1 liter = 1000 mL

**WHEN WEIGHING DIAPERS: 1 mL = 1 gm**

KNOW Essential Equivalents

IMPORTANT when CALCULATING MEDICATION DOSAGES

1 kg = 1000 gm

1 gm =1000 mg

1 mg = 1000 mcg

1 gm =15 gr (grain)

1 gr = 60 mg

Conversions

1 lb = 16 oz

∗ 12 lbs 5 oz5 oz = 5/165 ÷ 16 = 0.312512.31 lbs

∗9.75 lbs0.75 lbs = ? oz0.75 x 16 = 12 oz9 lbs 12 oz

∗25 ½ lbs = 25.5 lbs25 ¼ lbs = 25.25 lbs25 ¾ lbs = 25.75 lbs

Conversions

1 kg = 2.2 lbs

∗ 6 kg x 2.2 = 13.2 lbs

∗ 8.44 lbs ÷ 2.2 = 3.84 kg

∗ 25.75 lbs ÷ 2.2 = 11.7 kg

Conversions

1 in = 2.54 cm

∗ 21 in x 2.54 = 53.34 cm

∗ 78 cm ÷ 2.54 = 30.71 in

Safe Dosage Calculations

Ordered: Ciprofloxacin 400mg IV every 12 hrAvailable in vial: 500 mg in 2 mLSafe dose range: 10-20 mg/kg/DAY (24 hrs)Patient weight: 42.56 kg

#1. Safe dose range is 425.6 to 851.2 mg/DAY

42.56 kg x 10 mg/kg/day = 425.6

42.56 kg x 20 mg/kg/day = 851.2

#2. Actual dose = 800 mg/DAY (24 hrs)

#3. Actual dose is within safe range.

#4. YES, dose is safe.

Safe Dosage Calculations

Ordered: Tylenol 320 mg PO every 6 hrs prnAvailable in bottle of oral suspension: 80mg/mLSafe dose range: 10 – 15 mg/kg/DOSE every 6 hrsPatient weight: 14.42 kg

#1. Safe dose range is 144.2 to 216.3 mg/DOSE

14.42 kg x 10 mg/kg/dose = 144.2

14.42 kg x 15 mg/kg/dose = 216.3

#2. Actual dose = 320 mg/DOSE

#3. Actual dose is above safe range

#4. NO, dose is NOT safe.

Amount to Administer

Ordered: Cefuroxime 275 mg PO BIDAvailable in bottle of oral suspension: 125 mg/mL

#1. 1 mL__ = ? mL_125 mg 275 mg

#2. 1 x 275 = 275 125 x ? mL = 275 (or 275 ÷ 125 = ? mL)? = 2.2mL

#3. Administer 2.2 mL (275 mg)

Amount to Administer

Ordered: Dilantin 35 mg IV nowAvailable in vial: 100 mg/2 mL

#1. 2 mL__ = ? mL_100 mg 35 mg

#2. 2 x 35 = 70 100 x ? mL = 70 (or 70 ÷ 100 = ? mL) ? = 0.7 mL

#3. Administer 0.7 mL (35 mg)

Dilutions & Concentrations

Ordered: Ciprofloxacin 400mg IV q12 hrAvailable in vial: 400 mg in 1.6 mLCorrect concentration: 10 mg/mL

How many mL of normal saline (NS) wouldyou add to dilute 400 mg of Ciprofloxacinand have the correct concentration?

Dilutions & Concentrations

Ordered: Ciprofloxacin 400mg IV every 12 hrAvailable in vial: 400 mg in 1.6 mLCorrect concentration: 10 mg/mL#1. 1 mL = ? mL__

10 mg 400 mg

#2. Total volume needed for correct concentration = 40 mL10 x ? mL = 400 (or 400 ÷ 10 = ? mL)? = 40 mL

#3. 400 mg of Ciprofloxacin = 1.6 mL40 mL – 1.6 mL = 38.4 mL

#4. Add an additional 38.4 mL of NS

Dilutions & Concentrations

Ordered: Levaquin 300 mg IV every 24 hrs. - to beinfused over 90 minutes. Available: Levaquin in a syringe pre-mixed with D5WCorrect concentration: 5 mg/mL

Based on the correct concentration, how many mLof solution is in the syringe?

#1. 1 mL = ? mL_5 mg 300 mg

#2. Total volume needed for correct concentration = 60 mL5 x ? mL = 300 (or 300 ÷ 5 = ? mL) ? = 60 mL

#3. The total volume in the pre-mixed syringe is 60 mL.

IV Infusion Rates/Times

What is the correct IV rate (in mL/hr) to infuse 50 mL over 40 minutes?

#1. 50 mL X 60 min = 300040 min 1hr. 40

#2. 3000 ÷ 40 = 75 mL/hr

#3. IV rate = 75 mL/hr

IV Infusion Rates/Times

What is the correct IV rate (in mL/hr) toinfuse 50 mL over 40 minutes?

#1. 50 mL = ? mL40 min 60 min

#2. (50 X 60) ÷ 40 = 75 mL/hr

#3. IV rate = 75 mL/hr

IV Infusion Rates/Times

Patient needs 1245 mL/day of IV fluid intake

#1. 1245 mL = ? mL24 hr 1 hr

#2. 1245 ÷ 24 = 51.88 mL/hr

#3. IV rate = 52 mL/hr

Total Fluid Intake

From 1000-1900 (9 hours), patient had the following:

* IV running at 20 mL/hr

* Oral intake of 1 cup of milk & 120 mL of water(1 cup = 8 oz)

What was the patient’s total fluid intake from1000 to 1900 (9 hrs)?#1. Total intake from 1000-1900:

IV: 9 hrs@20 mL/hr = 180 mL PO: milk: 8 oz x 30 mL/oz = 240 ml

water = 120 mL

#2. 180 + 240 + 120 = 540 mL

#3. Total fluid intake was 540 mL

Daily Maintenance Fluids Needs

Maintenance formula based on weight:

• 100 ml/kg/day for first 10 kg of body weight

• 50 ml/kg/day for second 10 kg of body weight

• 20 ml/kg/day for each additional kg of body weight

¹Hockenberry, M. (2004). Wong’s Clinical Manual of Pediatric Nursing (6th ed), p. 103.

Daily Maintenance Fluids Needs

Child weighs 17.56 kg

#1. 100 x 10 = 1000 mL

#2. 50 x 7.56 = 378 mL

#3. 1000 + 378 mL = 1378 mL

#4. For maintenance, the child needs 1378 mL of fluid intake per day.

Daily Maintenance Fluids Needs

Child weighs 39.17 kg

#1. 100 x 10 = 1000 mL

#2. 50 x 10 = 500 mL

#3. 20 x 19.17 = 383.4 mL

#4. 1000 + 500 + 383 mL = 1883 mL

#5. For maintenance, the child needs 1883 mL of fluid intake per day.

Caloric Intake

Infant’s total intake for 24 hr: 5 bottlesEach bottle contained: 2.5 oz of formulaFormula: 24 calories/oz Infant weight: 2.78 kgInfant age: 3 weeks

How many calories did the infant receive inthe past 24 hours?

#1. 5 x 2.5 = 12.5 oz/day

#2. 12.5 x 24 = 300 calories/day (300 kcal/day)

Caloric Intake

In the past 24 hours, did the infant receivecalories at or above the minimum?Based on age and weight; infant needs a minimum of108 cal/kg/day.²

#3. 108 x 2.78 = 300.24 or 300 calories/dayMinimum intake = 300 calories/day Actual intake = 300 calories/day

#4. YES, caloric intake is at or above the minimum.

2 Hockenberry, M. (2004). Wong’s Clinical Manual of Pediatric Nursing (6th ed), p. 103.

Caloric Intake

Infant’s total intake for 24 hr: 6 bottlesEach bottle contained: 3 oz of formulaFormula: 20 calories/oz Infant weight: 3.9 kgInfant age: 4.5 weeks

How many calories did the infant receive inthe past 24 hours?

#1. 6 x 3 = 18 oz/day

#2. 18 x 20 = 360 calories/day (360 kcal/day)

Caloric Intake

In the past 24 hours, did the infant receivecalories at or above the minimum?

Based on age and weight; infant needs a minimumof 108 cal/kg/day. ²

#3. 108 x 3.9 = 421.2 or 421 calories/dayMinimum intake = 421 calories/day Actual intake = 360 calories/day

#4. NO, caloric intake is NOT at or above theminimum.

2 Hockenberry, M. (2004). Wong’s Clinical Manual of Pediatric Nursing (6th ed), p. 103.

That’s All for Now . . .

Thanks for your attention!

If you have questions, be sure to:

*Contact your Clinical Instructor

*Contact your Academic Coach

*Contact the Student Success Coordinator-Ceil Flores cflores@uta.edu

*Contact your Lead Teacher, Jenny Roye

N4431 Lead Teacher: roye@uta.edu

Be prepared – keep studying!