Intravenous Solutions, Equipment, and Calculations Chapter 14

Intravenous Solutions, Equipment, and Calculations

Chapter 14

2

IV Components

Abbreviation Solution ComponentD Dextrose

W Water

S Saline

NS Normal Saline (0.9% NaCl)

NaCl Sodium Chloride

RL Ringer’s Lactate

LR Lactated Ringer’s

3

Normal Serum Osmolarity• Hypotonic

– Used to dilute excess serum electrolytes• e.g.: 0.45% Saline

• Isotonic– Used to expand volume and maintain normal

tonicity• e.g.: 0.9% Saline, Lactated Ringer’s, 5% Dextrose

4

Normal Serum Osmolarity

• Hypertonic– Used to correct electrolyte imbalances

• e.g.: 5% Dextrose and 0.9% Saline; 5% Dextrose and Lactated Ringer’s

5

IV Solution Label

6

Standard Straight Gravity Flow IV

7

IV with Piggyback (IV PB)

8

IV Flow Rate: mL per hour

• Regulate an IV volume by electronic infusion pump or controller calibrated in mL per hour

Total mL

Total hours

X mL

1 hour

mL per hour

(rounded to a whole number)

9

Calculation of IV Flow Rate: mL per hour

• Order reads: D5W 250 mL IV over the next 2 hours by infusion pump

10

Calculation of IV Flow Rate: mL per hour

• Step 1 - Think–Pump is set by the rate of mL per hour. –So, if 250 mL is to be infused in two hours,

how much will be infused in one hour?• 125 mL will be infused in one hour• You would set the pump at 125 mL per hour

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IV Flow Rate: mL per hour• Step 2 - Use ratio-proportion formula:

Total mL

Total h

X mL

1 hmL/h

250 mL

2 hX mL

1 hX 125 mL

Therefore, set pump at 125 mL per hour (125 mL per hour)

12

IV Flow Rate in mL per hour:Infusion Rate is less than 1 hour

Total mL ordered

Total min ordered

X mL/h

60 min/h

X mL/h

(rounded to a whole number)

13

Calculation of mL per hour:Infusion Rate is less than 1 hour

• Order: – Ampicillin 500 mg IV in 50 mL D5½NS in 30

min by controller

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Calculation of mL per hour:Infusion Rate is less than 1 hour

• Step 1 – Think– Controller is set by the rate of mL per hour – If 50 mL is to be infused in 30 minutes

• 100 mL will be infused in 60 minutes

15

Calculation of mL per hour:Infusion Rate is less than 1 hour

• Step 1 – Think– Because 100 mL is twice as much as 50 mL

and 60 minutes is twice as much as 30 minutes

• Set rate of controller at 100 mL per hour to infuse 50 mL per 30 min

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Calculation of mL per hour:Infusion Rate is less than 1 hour

• Step 2Total mL ordered

Total min ordered

X mL/h

60 min/h

50 mL

30 min

X mL/h

60 min/ h

30 X 3000

X 100 mL/h

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IV Flow Rate: drops per min• Formula for IV flow rate for manually

regulated IVs ordered in mL per hour or for minutes

RCT

V

Volume (mL)

Time (min)

Calibration or drop factor (drops per mL)

gtt per min

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IV Flow Rate: drops per min

• Carry calculations to one decimal.

• Round drops per min to the nearest whole number.

• Watch - count only whole drops

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Calculation of drops per min• Physician orders:

– D5W IV at 125 mL per hour

• Infusion set is calibrated for a drop factor of 10 drops per mL

• Calculate IV flow rate in drops per min

• Notice that the mL cancel out, leaving drops per min

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Calculation of drops per min

mL 1

gtt 10

min 60

mL 125gtt/mL 10

min 60

mL 125

gtt/min 820.6

1

• Use your watch to count drops and adjust roller clamp to deliver 21 drops per min

21

Calculation of drops per min:Microdrip Drop Factor

• When IV drop factor is 60 drops per mL (microdrip sets)– Flow rate in drops per min is same as volume

ordered in mL per hour

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Calculation of drops per min: Microdrip Drop Factor

• Order: – D5W NS IV at 50 mL per h

• Drop factor is 60 drops per mL

• Notice order, 50 mL per hour, is the same as the flow rate of 50 drops per min when drop factor is 60 drops per mL

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Calculation of gtt per min: Microdrip Drop Factor

mL per gtt min 60

mL 60

50

50 drops per min

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Drop Factor ConstantsDrop Factor Drop Factor Constant

10 drops per mL

15 drops per mL

20 drops per mL

60 drops per mL

610

60

415

60

320

60

160

60

25

min 3

gtt 125

Drop Factor Constants

• Administer 125 mL per hour IV with 20 drops per mL infusion set

gtt/mL 20min 60

mL 125

3

1

gtt/min 42gtt/min 641 .

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IV Flow Rate Shortcut Method

• Shortcut to calculate IV flow rate is:

mL per hour

Drop factor constantgtt per min

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Adjusting IV Flow Rate

• Check for institutional policy regarding correcting off-schedule IV rates and the percentage of variation allowed.

• Variation should not exceed 25 percent

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Adjusting IV Flow Rate

• If adjustment is permitted– Use following formula to recalculate the mL

per hour and gtt per min for the time remaining and the percentage of variation.

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Adjusting IV Flow Rate

• Step 1:

• Step 2:

• Step 3:

min per gtt CT

V

variation %min per gtt Ordered

min per gtt Orderedmin per gtt Adjusted

hour per mL edRecalculathours Remaining

volume Remaining

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Adjusting IV Flow Rate

• % variation will be positive (+) if administration is slow and rate has to be increased

• Negative () if administration is too fast and rate has to be decreased

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Calculation of IV Flow Rate Adjustment

• Order: 500 mL LR to run over 10 hour at 50 mL per hour – Drop factor is 60 drops per mL and IV is

correctly infusing at 50 drops per min – After 2½ hours, 300 mL is remaining– Almost half of total volume infused in one-

quarter the time

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Calculation of IV Flow Rate Adjustment

• IV infusion is ahead of schedule

• Compute a new rate of 300 mL to complete IV fluid order in remaining 7½ hours.

• Patient would require close assessment for fluid overload

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Calculation of IV Flow Rate Adjustment

Remaining volume

Remaining hours

V

TC

40 mL

60 min60 gtt per mL

300 mL

7.5 h40 mL per hour

1

1

40 gtt per min

Adjusted flow rate

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Calculation of IV Flow Rate Adjustment

Adjusted gtt per min Ordered gtt per min

Ordered gtt per min% variation

%. 202050

10

50

5040

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IV Push Rate Calculation• Caution:

– IV drugs are potent and rapid acting.

– Never infuse IV push drugs more rapidly than recommended.

36

IV Push Rate Calculation• Caution:

– Some drugs require further dilution after reconstitution.

– Read package inserts and drug resources for administration guidelines.

37

IV Push Rate Calculation

desiredAmount X

desired Dosage

handon Amount

handon Dose

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Calculation of IV PushIncremental Rate

• Order: Ativan 3 mg IV Push 20 min preoperatively

• Supply: Ativan 4 mg per mL with drug literature guidelines of “IV infusion not to exceed 2 mg/min”

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Calculation of IV PushIncremental Rate

• How much Ativan should you prepare?– Step 1. Convert

• No conversion is necessary

– Step 2. Think• You want to give less than 1 mL

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Calculation of IV Push Incremental Rate

• How much Ativan should you prepare?– Step 3. Calculate

4 mg

1 mL

3 mg

X mL4 X 3

X 0.75 mL

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Calculation of IV PushIncremental Rate

• What is a safe infusion time?

3X2min X

mg 3

min 1

mg 2

2X

2

3

2

X 11

2 min

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Calculation of IV PushIncremental Rate

• How much should you infuse every 15 seconds?– 1 min = 60 seconds– 1½ min = 1½ 60 = 90 seconds

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Calculation of IV PushIncremental Rate

0.75 mL

90 secX mL

15 sec

90X 11.25

90X

90

11.25

90• X = 0.125 mL = 0.13 mL of Ativan 4 mg per mL

infused IV push every 15 seconds will deliver 3 mg of Ativan

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IV Infusion Time

• To calculate IV infusion time– mL is known:

hours Total hour per mL

volume Total

Or, use ratio-proportion: mL

h

Total mL

X total h

45

IV Infusion Time

• To calculate IV infusion time

• Flow rate in drops per min– Drop factor and volume are known

46

IV Infusion Time

V

TC R; “T” is the unknown

Or, use ratio-proportion: mL

h

Total mL

X total h

47

mL

h

Total mL

X total h

IV Fluid Volume

• To calculate total infusion volume– mL is known:

volume Totalhour per mLhours Total

Or, use ratio-proportion:

48

IV Fluid Volume• To calculate IV volume

– Flow rate (drops per min), drop factor, and time are known:

“V” is the unknownV

TC R;