Advanced Adult Intravenous Calculations

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Advanced Adult Intravenous Calculations
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IV Flow Rate mL/h

• To regulate an IV volume by electronic infusion
  pump or controller calibrated in mL/h, calculate

(rounded to a whole number)
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Calculation of IV Flow Rate mL/h (continues)

• Order reads D5W 250 mL IV over the next 2 h by
  infusion pump
• Step 1
• Think. The 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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Calculation of IV Flow Rate mL/h (continued)

• Step 2
• Use the formula

Therefore, set the pump at 125 mL per hour (125
mL/h).
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Calculation of IV Flow Rate mL/h (continued)

• Step 2
• Use the formula

Therefore, set the pump at 125 mL per hour (125
mL/h).
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Calculation of IV Flow Rate mL/h (continued)

• Step 2
• Use the formula

Therefore, set the pump at 125 mL per hour (125
mL/h).
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Calculation of mL/hInfusion Rate is lt 1 h
(continued)

• Step 2

2
1
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IV Flow Rate gtt/min

• The formula method to calculate IV flow rate for
  manually regulated IVs ordered in mL/h or for a
  prescribed number of minutes is

Calibration or drop factor (gtt/mL)
Volume (mL)
Time (min)
gtt/min
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IV Flow Rate gtt/min

• Carry calculations to one decimal. Round gtt/min
  to the nearest whole number, because you can
  watch-count only whole drops.

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Calculation of gtt/min

• The physician orders D5W IV _at_ 125 mL/h. The
  infusion set is calibrated for a drop factor of
  10 gtt/mL. Calculate the IV flow rate in
  gtt/min. Notice that the mL cancel out, leaving
  gtt/min.

1
6
Use your watch to count the drops and adjust the
roller clamp to deliver 21 gtt/min.
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Calculation of gtt/min Microdrip Drop Factor

• When the IV drop factor is 60 gtt/mL (microdrip
  sets), then the flow rate in gtt/min is the same
  as the volume ordered in mL/h.

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Calculation of gtt/min Microdrip Drop Factor

• Order D5W NS IV _at_ 50 mL/h. The drop factor is
  60 gtt/mL. Notice that the order, 50 mL/h, is
  the same as the flow rate of 50 gtt/min when the
  drop factor is 60 gtt/mL.

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Drop Factor Constants
Drop Factor Drop Factor Constant
10 gtt/mL
15 gtt/mL
20 gtt/mL
60 gtt/mL
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Adjusting IV Flow Rate (continued)

• Step 1
• Step 2
• Step 3
• The variation will be positive () if the
  administration is slow and the rate has to be
  increased, and negative (?) if the administration
  is too fast and the rate has to be decreased.

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Calculation of IV Flow Rate Adjustment (continued)
Adjusted flow rate
1
1
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IV Push Rate Calculation
Dosage Desired
Quantity of Time Recommended
IV Push Rate Time
Supply Dosage Recommended
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Calculation of IV Push Incremental Rate
(continues)

• Order Ativan 3 mg IV Push 20 min preoperatively
• Supply Ativan 4 mg/mL with drug literature
  guidelines of IV infusion not to exceed 2
  mg/min.

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Calculation of IV Push Incremental Rate
(continues)

• Order Ativan 3 mg IV Push 20 min preoperatively
• Supply Ativan 4 mg/mL with drug literature
  guidelines of IV infusion not to exceed 2
  mg/min.

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Calculation of IV Push Incremental Rate
(continued)

• What is a safe infusion time?
• Use Formula

• Or, ratio-proportion

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Calculation of IV Push Incremental Rate
(continued)

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

• X 0.125 mL 0.13 mL of Ativan 4 mg/mL infused
  IV push every 15 seconds will deliver 3 mg of
  Ativan.

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IV Fluid Volume

• To calculate total infusion volume mL is known
• To calculate IV volume flow rate (gtt/min), drop
  factor, and time are known

Or, use ratio-proportion
V is the unknown
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Standard Weight Based Heparin Protocol
Standard Weight Based Heparin Protocol
For all patients on heparin drips
1. Weight in KILOGRAMS. Required for order to be processed kg
2. Heparin 25,000 U in 250 mL of ½ NS. Boluses to be given as 1000 U/mL.
3. APTT q.6h or 6 hours after rate change q.d. after two consecutive therapeutic APTTs.
4. CBC initially and repeat every day(s).
5. Obtain APTT and PT/INR on day one prior to initiation of therapy.
6. Guaiac stool initially then every day(s) until heparin discontinued. Notify if positive.
7. Neuro checks every hours while on heparin. Notify physician of any changes.
8. D/C APTT and CBC once heparin drip is discontinued, unless otherwise ordered.
9. Notify physician of any bleeding problems.
10. Bolus with 80 U/kg. Start drip at 18 U/kg/h.
11. If APTT is lt 35 secs Rebolus with 80 U/kg and increase rate by 4 U/kg/h
12. If APTT is 3644 secs Rebolus with 40 U/kg and increase rate by 2 U/kg/h
13. If APTT is 4575 secs Continue current rate
14. If APTT is 7690 secs Decrease rate by 2 U/kg/h
15. If APTT is gt 90 secs Hold heparin for 1 hour and decrease rate by 3 U/kg/h
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Standard Weight Based Heparin Protocol Worksheet
(continues)
Standard Weight Based Heparin Protocol
Worksheet Round Patients Total Body Weight to
Nearest 10 kg kg DO NOT Change the
Weight Based on Daily Measurements

FOUND ON THE ORDER FORM Initial Bolus (80 U/kg)
U mL Initial
Infusion Rate (18 U/kg/h) U/h
mL/h
Make adjustments to the heparin drip rate as
directed by the order form. ALL DOSES ARE ROUNDED
TO THE NEAREST 100 UNITS
Date Time APTT Bolus Rate Change U/h mL/h New Rate RN 1 RN 2




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Standard Weight Based Heparin Protocol Worksheet
(continued)




If APTT is Then
lt 35 secs Rebolus with 80 U/kg and increase rate by 4 U/kg/h
3644 secs Rebolus with 40 U/kg and increase rate by 2 U/kg/h
4575 secs Continue current rate
7690 secs Decrease rate by 2 U/kg/h
gt 90 secs Hold heparin for one hour and decrease rate by 3 U/kg/h
Signatures Initials



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IV Heparin Protocol

• Bolus patient with heparin 80 U/kg body weight
  and start drip at 18 U/kg/h
• Patients weight 110 lb
• How many units of heparin should the patient
  receive?
• Step 1 Calculate pt.s wt. in kg ( 1kg2.2 lb)
• Step 2 Calculate the heparin bolus dosage.
• 80 U/kg X 50 kg 4000 U
• This pt should receive 4000 U IV hep. As a bolus

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Calculate the number of milliliters to admin. For
the bolus

• Supply heparin 1000 U/mL
• Think You want to give 4000 U, which is 4 times
  1000 U/mL, so you want to give 4 times 1 mL or 4
  mL.
• 4
• D 4000 U
• H X Q 1000 U X 1 mL 4 mL
• Admin. 4 mL of heparin for the bolus

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Calculate the infusion rate forthe heparin IV
drip

• Protocol Start drip at 18 U/kg/h
• Supply heparin 25,000 U/250 mL or 100 U/ml
• 18 U/kg/h X 50 kg 900 u/h
• Think, you want to admin. 9 times 1 mL or 9mL for
  the heparin infusion
• 9
• D 900 U/h
• H X Q 100 U X 1 mL/h 9 mL/h
• 1

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To calculate IV heparin flow ratein mL/h

• D (U/h desired)
• H (U have on hand) X Q (mL you have on
  
• 
  hand)R (mL/h)
• Or ratio or supply is equiv. to ratio of desired
  dosage rate
• Supply U Desired U/h
• Supply mL X mL/h

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Order D5W 500 mL w/ heparing25,000 U IV at 1000
U/h

• D 1000 U/h
• H X Q 25,000 U X 500 mL R (mL/h
• 1000 U/h 1 20
• 25,000 U X 500 mL 1000mL/h 20 mL/h
• 50 50
• 1

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Order D5W 500 mL w/ hep 25,000 U IV at 850 U/h

• Calculate the flow rate in mL/h
• D 1 17
• H X Q 850 U/h X 500mL 850 mL/h 17
• 25,000 U 50
• 50
  1

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IV Flow Rate Ordered Per Minute

• To determine the flow rate (mL/h) for IV
  medications ordered per minute (such as mg/min)
• Step 1 Calculate the dosage in mL/min
• Step 2 Calculate the flow rate of the
  
  
  quantity to administer in mL/h

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Ratio/Proportion

• 25,000 U 850 U/h
• 500 mL X mL/h
• 25,000 X 425,000
• 25,000 X 425,000
• 25,000 25,000
• X 17 mL/h

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IV Flow Rate Ordered by kg/min

• To calculate flow rate (mL/h) for IV medications
  ordered by weight per minute (such as mg/kg/min)
• Step 1 Convert to like units, such as mg to
  mcg or lb to kg.
• Step 2 Calculate desired dosage per minute.
• Step 3 Calculate the desired dosage in
  mL/min.
• Step 4 Calculate the flow rate of the
  quantity to administer in mL/h.

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Verifying Safe Drug Dosage Recommended Per
Minute

• To check safe dosage of IV medications ordered in
  mL/h
• Step 1 Calculate mg/h.
• Step 2 Calculate mg/min.
• Step 3 Compare recommended dosage and
  ordered dosage to decide if the dosage is
  safe.

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Verifying Safe Drug Dosage Recommended by kg/min

• To check safe dosage of IV medications
  recommended in mg/kg/min and ordered in mL/h
• Step 1 Convert to like units, such as mg to
  mcg or lb to kg.
• Step 2 Calculate recommended mg/min.
• Step 3 Calculate ordered mg/h.
• Step 4 Calculate ordered mg/min.
• Step 5 Compare ordered and
  recommended dosages decide if safe.

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IV and IV PB Flow Rates with Fluid Volume
Restrictions (continues)

• Follow these six steps to calculate the flow rate
  of an IV, which includes IV PB. Calculate
• Step 1 IV PB flow rate

or use
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IV and IV PB Flow Rates with Fluid Volume
Restrictions (continued)

• Step 2 Total IV PB time
• Step 3 Total IV PB volume
• Step 4 Total regular IV volume
• Step 5 Total regular IV time

Time for one dose of doses in 24 h
Volume of one dose of doses in 24 h
Total volume IV PB volume
Total time IV PB time
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IV and IV PB Flow Rates with Fluid Volume
Restrictions (continued)

• Step 6 Regular IV flow rate

or use
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THE END