© 2010 the mcgraw-hill companies, inc. all rights reserved 10-1 mcgraw-hill math and dosage...

© 2010 The McGraw-Hill Companies, Inc. All rights reserved

10-1

McGraw-Hill

Math and Dosage Calculations for Health

Care Third EditionBooth & Whaley

Chapter 10: Intravenous Dosages

© 2010 The McGraw-Hill Companies, Inc. All rights reservedMcGraw-Hill

10-2

Learning Outcomes

10.1 Identify the components and concentrations of IV solutions.

10.2 Distinguish basic types of IV equipment.

10.3 Calculate IV flow rates for both electronically controlled and manually controlled IV devices.

10.4 Adjust the flow rate for IV infusions.


10-3

Learning Outcomes (cont.)

10.5 Calculate infusion time based on volume and flow rate.

10.6 Calculate volume based on infusion time and flow rate.

10.7 Reconstitute and calculate medication for intermittent IV infusions.


10-4

Intravenous (IV) fluidsDelivered directly into the bloodstream

via a vein

IncludesSolutionsMedications Blood

Rapid effect

Results can be fatal if wrong medication or

dosage is given.

Introduction


10-5

IV Solutions – FUNCTIONS

ReplacementElectrolytes Fluids

Maintenance Fluid balanceElectrolyte

balance

KVO fluidsKeep Vein OpenMaintain an IV

line

Therapeutic – Delivers medication to patient


10-6

IV Solutions – IV LABELS

Solution labelsName of

components

The exact amount of components


10-7

IV Solutions – IV LABELS (cont.)

Rule 10-1Rule 10-1 In abbreviations for IV solutions:

Letters identify components

Numbers identify concentration


10-8

IV Solutions – IV LABELS (cont.)

5% dextrose in Lactated Ringer’s solution might be abbreviated in any of the following ways:D5LRD5LR5% D/LR D5%LR

ExampleExample


10-9

IV Solutions – COMMONLY USED ABBREVIATIONS

ABBREVIATION SOLUTION

D10W 10% dextrose in water

D5W 5% dextrose in water

W; H2O Water

NS; NSS Normal saline (0.9% NaCl)

LR Lactated ringer’sRL Ringer’s lactate


10-10

IV Solutions – COMMONLY

USED ABBREVIATIONS (cont.)ABBREVIATION SOLUTION

½ NS; ½ NSS One-half normal saline solution (0.45% NaCl)

1/3 NS; 1/3 NSS One-third normal saline solution (0.3% NaCl)

¼ NS; ¼ NSS One-fourth normal saline solution (0.225% NaCl)


10-11

IV Solutions – IV CONCENTRATIONS

5% Dextrose – contains 5 g of dextrose per 100 mL

Normal saline 0.9% saline Contains 900 mg, or

0.9 g, of sodium chloride per 100 mL.

½ Normal saline 0.45% saline Contains 450 mg, or

0.45 g, of sodium chloride per 100 mL


10-12

IV Solutions – IV CONCENTRATIONS (cont.)

Choice of solution is based on patient requirements

Isotonic IV solutionsDo not affect fluid

balance of cells and tissues

D5W, NS, LR


10-13


Hypotonic IV solutionsMove fluid into surrounding cells and tissues

Restore proper fluid level in cells and tissues

Used to correct dehydration

0.45% NS, 0.3% NS


10-14


Hypertonic IV solutionsDraw fluid from cells and tissues into blood

stream

Used to correct severe fluid shifts (burns)

3% Saline


10-15


Rule 10-2Rule 10-2Patients with normal electrolyte levels are likely to receive isotonic solutions.

Patients with high electrolyte levels will receive hypotonic solutions.

Patients with low electrolyte levels will receive hypertonic solutions.


10-16

IV Solutions – COMPATIBILITY

Additives Medications, electrolytes, and nutrientsIf not prepackaged, will have to mix.


10-17

IV Solutions –

COMPATIBILITY (cont.)

Rule 10-3Rule 10-3

Before combining any medications, electrolytes, or nutrients with an IV solution, be sure the components are compatible.


10-18

IV Solutions –

COMPATIBILITY (cont.)

Examples of incompatible medications/solutions

Ampicillin D5W

Cefotaxime sodium Sodium bicarbonate

Diazepam Potassium chloride

Dopamine HCl Sodium bicarbonate

Penicillin Heparin

Penicillin Vitamin B complex

Sodium bicarbonate Lactated Ringer’s

Tetracycline Calcium chloride


10-19

IV Equipment

Primary LineBag or bottle of IV solution –

500 mL or 1000 mL

TubingDrip chamberClamp – regulate IVInjection ports

Add medication or compatible fluid Attach a second line


10-20

Roller clamp


10-21

IV Equipment (cont.)

TubingMacrodrip

Larger drops in drip chamberInfusion rates of 80 mL/h or more

MicrodripSmaller drops in drip chamberInfusion rates less than 80 mL/h and KVOPediatric and critical care IV’s


10-22

IV Equipment – MONITORING

ManuallyHang the bag hung 36 inches above

patient’s heart

Adjust flow rate using roller or screw clamps

Usually adjusted in gtt/min


10-23

IV Equipment –MONITORING

(cont.) Electronic devices

Rate controllersGravity

Pincher maintains flow rate

Alarm sounds when preset flow rate is not maintained


10-24

IV Equipment – MONITORING (cont.)

Infusion pumpsApply pressure to deliver set volume

per minute

Sensor /alarmImproper rateEmpty bag

Must monitor site for infiltration


10-25


Syringe pumpsSyringe is inserted into pump

Incompatible medications or fluids

Pediatric doses

Provide precise controlover rate


10-26

Patient-Controlled Analgesia (PCA) DevicePatient controls medication

within preset limits per physician’s order

Records number of times button is pushed

Used to monitor effectiveness of pain relief prescription



10-27


Volume control setsImprove accuracy of

Manual IV setupsElectronic rate controllersSmall volumes of fluids or

medicationsUses: pediatric or critical care IVsExamples: Buretrol, Soluset, and

Volutrol


10-28

Peripheral and Central IV Therapy

Peripheral IV TherapyAccesses the circulatory system through a

peripheral veinHand, forearm, foot, legScalp vein in infants


10-29

Peripheral and Central IV Therapy (cont.)

Central IV TherapyCentral line

provides direct access to major veins

Used when patient needs:

Large amounts of fluids

A rapid infusion of medication

Infusion of highly concentrated solutions

Long-term IV therapy


10-30


Central IV TherapyPICC – peripherally inserted central catheter

Inserted into arm vein and threaded into a central vein

Port-A-CathSurgically placed under the skin for access to

central veinAccessed through the skinFor intermittent use


10-31


Rule 10-4Rule 10-4

Never flush a sluggish IV with a syringe.

May push a clot into the circulatory system


10-32


Pain or swelling at the siteInfiltration

Needle or catheter becomes dislodged from the vein

Fluid infuses into the surrounding tissues

SignsSwellingDiscomfortCoolness at the

infiltration siteSizeable decrease in

flow rate


10-33


PhlebitisInflammation of the vein

CausesIrritation by IV

additivesMovement of

needle or catheterLong-term IV therapy

Signs / SymptomsPain at or near

siteHeatRednessSwelling at site


10-34


Treatment of infiltration or phlebitisStop IV infusionRestart in a different site


10-35

Practice

Isotonic

Hypotonic

Hypertonic

Central line

Phlebitis

Infiltration

PCA

Macrodrip

Microdrip

A. 60 gtt/mL

B. Patient controls medication

C. Fluid infuses into tissues

D. For normal electrolyte levels

E. PICC

F. For high electrolyte levels

G. 15 gtt/min

H. Inflammation of a vein

I. For low electrolyte levels

Matching:

I

H

G

F

A

C

B

E

D


10-36

Calculating Flow Rates

Flow rate - how fast the IV infusesCalculated from

• Amount of fluid to be infused

• Length of time for infusion

Expressed as milliliters per hour


10-37

Calculating Flow Rates (cont.)

Rule 10-5 Rule 10-5 To calculate flow rates in milliliters per hour, identify the following:

V (volume) – expressed in millilitersT (time) – expressed in hours (convert units as necessary)F (flow rate) – rounded to nearest tenth

Use the formula method with or dimensional analysis

to determine the flow rate in milliliters per hour.


10-38


Find the flow rate

Ordered: 500 mg ampicillin in 100 mL NS to infuse over 30 minutes

Convert minutes to hour: 30 ÷ 60 = 0.5 hr

Flow rate = 200 mL/hr

ExampleExample


10-39


Manually regulated IVs Calculated as gtt/min

Macrodrip Larger drops Drop factors: 10 gtt/mL,

15 gtt/mL, or 20 gtt/mL

Microdrip tubing Smaller drops Drop factor: 60 gtt/mL


10-40


Rule 10-6 Rule 10-6 To determine the flow rate (f) in drops per minute:

1. Change the flow rate mL/h (F) to gtt/min (f) using

the formula:

F = flow rate; mL/hr

C = calibration factor of tubing; gtts/mL

60 = number of minutes in 1 hour

2. Round to nearest whole number.


10-41


Find the flow rate in drops perminute that is equal to 35 mL/hour using 60 gtt/mL microdrop tubing.

f = 35 gtt/min

ExampleExample


10-42


Counting drops is not preciseCheck IV hourly to see

if it is on schedule

Before adjusting the rate, check facility policy


10-43


Rule 10–7Rule 10–7 To adjust the flow rate:

Recalculate the infusion using the volume remaining in the IV and the time remaining in the order.

Check the guidelines at your facility before adjusting the flow rate.


10-44


Original Order: 1500 mL NS over 12 hours

The IV was infusing at an original rate of 42 gtt/min using 20 gtt/mL macrodrip tubing.

After 3 hours, 1200 mL remain in the bag.

Flow rate adjustments must not exceed 25%.

ExampleExample


10-45


Use formula

f = 44 gtt/min

25% of original rate of 42 gtt/mL = 10.5

Rate can be adjusted up or down within a range of 32.5 to 52.5 gtt/min.

Rate can be adjusted to 44 gtt/min.

Example (cont.)

Example (cont.)


10-46

Practice

Calculate flow rate then determine if an adjustment is necessary.

Adjustment cannot exceed 25%.

Ordered: 250 mL NS over 2 hours (10 gtt/mL tubing)

After 30 minutes 100 mL infused.


10-47

Practice

Answer

25% of 21 = 5.25

Adjustment range = 15.75 to 26.75

You may adjust this infusion.

Original drop rate

f = 21 gtt/min

Adjusted rate

f = 17 gtt/min


10-48

Infusion Time and Volume

If not specified in the order you may have to calculate Duration – if fluid volume and flow rate is

known

Fluid volume – if the duration and flow rate is known


10-49

Infusion Time and Volume (cont.)

Rule 10-8 Rule 10-8 To calculate infusion time in hours ((T),), identify the:

V (volume) expressed in milliliters

F (flow rate) expressed in milliliters per hour

Fractional hours by multiplying by 60

F

VT

Use this formula or dimensional analysis to find T, the infusion time in hours.


10-50


Find the total time to infuse.

Ordered: 1000 mL NS to infuse at a rate of 75 mL/h

T = 13.3

Total time to infuse the solution = 13 hours and 20 minutes

ExampleExample


10-51


Find the total time to infuse.

Ordered: 750 mL LR to infuse at a rate of 125 mL/hr started at 11 p.m.

T = 6

The total time to infuse is 6 hours.

ExampleExample


10-52


Rule 10-9 Rule 10-9 To calculate the time when an infusion will be completed,

You must know:1. The time the infusion started in military time

2. The total time in hours and minutes to infuse the solution ordered


10-53


Rule 10-9 Rule 10-9 (cont.)

Since each day is only 24 hours long, when the sum is greater than 2400 (midnight), you must start a new day by subtracting 2400.

This will determine the time of completion, which will be the next calendar day.


10-54


Determine when the infusion will be completed.

Ordered: 750 mL LR to infuse at a rate of 125 mL/hr and was started at 11 p.m. on 08/04/08

Infusion time = 6 hours

11 p.m. = 2300 hrs

2300 + 6 hours = 0500 or 5:00 a.m. on 08/05/08

ExampleExample


10-55


Rule 10-10 Rule 10-10 To calculate infusion volume:Use the formula V = T x F or dimensional analysis to find V the infusion volume in mL.

T (time) must be expressed in hours

F (flow rate) must be expressed in milliliters per hour


10-56


Find the total volume infused in 5 hours if the infusion rate is 35 mL/h.

V = 5 h × 35 mL/h

V = 175 mL

175 mL will infuse in 5 hours

ExampleExample


10-57


Find the total volume infused in 12 hours if the infusion rate is 200 mL/h.

V = 12 h × 200 mL/h

V = 2400 mL

2400 mL will infuse in 12 hours

ExampleExample


10-58

Intermittent IV Infusions

IV medications may be administered intermittently with or without continuous IV therapy.

Delivered through IV secondary line SalineHeparin lock


10-59

Intermittent IV Infusions – SECONDARY LINES

“Piggyback” or IVPB

IV setup attaches to a primary line

Infuse medications or other compatible fluids on an intermittent basis

IVPB bags are smaller: 50, 100, or 150 mL


10-60

Intermittent IV Infusions – INTERMITTENT PERIPHERAL INFUSION DEVICES

Saline or heparin locks

An infusion port attached to an already inserted IV needle or catheter.

Allow direct injection of medication or infusion of IV medications.


10-61

Intermittent IV Infusions – INTERMITTENT PERIPHERAL INFUSION DEVICES (cont.)

No continuous flow of fluids

Requires flushing 2 to 3 times per day

Saline lock – uses saline as the flush

Heparin lock – uses heparin, an anticoagulant, as the flush


10-62

Intermittent IV Infusions (cont.)

Preparing and Calculating Intermittent InfusionsFlow rate is calculated the same as regular

IV infusions.Amount of fluid may be less and time to

infuse may be less than an hour.To calculate the flow rate you will need to

change the number of minutes into hours.


10-63


Rule 10-11 When preparing medication for an intermittent IV infusion:

Reconstitute the medication using the label and package insert.

Calculate amount to administer and the flow rate.


10-64


Ordered: Eloxatin 75 mg in 250 mL D5W IV piggyback over 90 minutes

Reconstitute with 20 mL of water for injection.

Dosage strength – see label

Calculate the amount to administer and the flow rate.

ExampleExample


10-65


Amount to administer

Flow rate using15 mL + 250 mL

A = 15 mL

F = 177 mL/h

Example (cont.)

Example (cont.)


10-66

Practice

Find total infusion time:

Ordered: 650 mL 0.45 NS at 40 mL/h started at 0315 08/09/08

T = 16.25 hours

Total infusion time = 16 hr 15 min

When will this IV be completed?

7:30 p.m. 08/09/08


10-67

Practice

Find the volume to administer:

Ordered: D5NS at 65 mL/hr for 8 hours

V = 8 h x 65 mL/h V = 520 mL

Ordered: NS at 100mL/h for 45 min

V = 0.75 h x 100 mL/hV = 75 mL


10-68

Apply Your Knowledge

Identify four functions of IV fluids.

ANSWERS

1.Replacement

2.Maintenance

3.KVO

4.Therapeutic


10-69

Apply Your KnowledgeHow many mg of sodium chloride is in 100

mL of normal saline?

How many mg of sodium chloride is in 100 mL of 0.45% NS?

ANSWER 900 mg NaCl

ANSWER 450 mg NaCl


10-70

Apply Your Knowledge

When you adjust the IV flow rate, what percentage of the original flow rate should you not exceed?

Flushing a sluggish IV will not cause harm.

True / False

ANSWER 25%

Flushing may push a clot into the circulatory system causing an obstruction.


10-71

End of Chapter 10

Wisdom consists of the anticipation of consequences.

~ Norman Cousins

© 2010 the mcgraw-hill companies, inc. all rights reserved 10-1 mcgraw-hill math and dosage...

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