1. Advanced Adult Intravenous Calculations
Chapter 16
Revised KBurger1108

2. IV Heparin Anticoagulant – prevention of clot formation
High alert medication
All heparin orders, dosage, vial, amount and calculations should be checked by another nurse
Available in various dosage strengths
See figure 16-1 page 406 in Pickar

3. Heparin Flow Rate
Set up a ratio-proportion with: - supply dosage strength [units per ml] - ordered infusion dose [units/hr per units/ml]
Example: Order: 500 mL D5W with Heparin 25,000 units to 850 units / hr 25,000units = units/hr mL X mL/hr
25,000X = 425,000 25, , = 17 mL/hr

4. Heparin Flow Rates Try these…
1. The doctor orders heparin to infuse at 800 unit per hour. The pre-mixed intravenous solution available is 250mL D5W with units heparin added. Calculate the infusion rate for delivery with an infusion pump.
2. The doctor orders heparin to infuse at 750 unit per hour. The pre-mixed intravenous solution available is 500mL D5W with units heparin added. Calculate the infusion rate for delivery with an infusion pump.
8 mL / hr
15 mL / hr

5. Standard Weight-Based Heparin Protocol
See p.408 Pickar
Standard Weight-Based Heparin Protocol
1. Weight in kilograms. Required for order to be processed ______kg
2. Heparin 25,000 units in 250mL 1/2NS. Bolus dosage strength 1000units/mL.
APTT q6hrs or 6 hrs after rate change; daily for 2 consecutive therapeutic APTTs.
CBC initially and repeat every ______day[s]
Obtain APTT and PT/INR on day one prior to initiation of therapy
Guaiac stool initially then every _____day[s] until heparin d/c
Neuro checks every _____hrs while on heparin
Discontinue APTT and CBC once heparin is discontinued
Notify physician of any bleeding problems
Bolus with 80 units/kg. Start drip at 18 units/kg/hr
If APTT is less than 35 seconds Rebolus with 80units/kg and increase rate by 4 units/kg/hr
If APTT is seconds Rebolus with 40units/kg and increase rate by 2 units/kg/hr
If APTT is seconds Continue current rate
If APTT is seconds Decrease rate by 2 units/kg/hr
If APTT is greater than 90 seconds Hold heparin for 1 hour and decrease rate by 3 units/kg/hr

6. Using the Heparin Protocol
Patient weight = 110 lbs Convert to kilograms = 50 kg
Calculate the heparin bolus Protocol states: Bolus with 80 units/kg 80 units X 50 kg = 4000 units
Calculate the bolus in milliliters Protocol states: Bolus dosage strength 1000 units/mL 1000 Units = Units 1 mL X mL = 4 mL

7. Using the Heparin Protocol
Calculate the starting infusion rate Protocol states: Start drip at 18 units/kg/hr Multiply by pt weight of 50 kg: 18units X 50 kg = 900units/hr Protocol states: Heparin 25,000 Units in 250 mL of ½ NS Units = Units/hr mL X mL/hr X = 9 mL/hr
Adjust infusion rate according to APTT results. Follow protocol guidelines. Examples: Client has APTT of:
Rebolus with 40units/kg/hr & increase rate by 2 units/kg/hr
Continue current rate
Decrease rate by 2units/kg/hr

8. IV Flow Rate Ordered “Per Minute”
Critical Care IV calculations
Determine electronic IV infusion rate (mL per hour) for IV medications ordered per minute (such as mg per min)
Step 1: Calculate dosage in mL per min
Step 2: Calculate flow rate in mL per hour

9. EXAMPLE: Ordered lidocaine 2g IV in 500 mL D5W @ 2 mg/min
Step 1 Calculate ml/min: 2000mg = 2mg/min 500mL X mL/min X = 0.5mL/min
Step 2 Calculate ml/hr: 0.5mL = X mL/hr
1 min min/hr X = 30ml//hr

10. IV Flow Rate Ordered by Kilogram per minute
Calculate electronic IV infusion rate (mL per hour) for IV medications ordered by weight per minute (such as mg per kg per min):
Step 1- Calculate desired dosage per minute
Step 2- Calculate desired dosage in mL per minute
Step 3- Calculate flow rate in mL per hour

11. EXAMPLE: 250mL of D5W with 225 mg of dobutamine to infuse @ 3mcg/kg/min. Client weighs 50 kg
Step 1- Calculate desired dosage per minute 0.003mg X 50 kg = 0.15mg/minute
Step 2- Calculate desired dosage in mL per minute 225mg = mg/min 250mL X mL/min X = 0.17 ml/min
Step 3- Calculate flow rate in mL per hour 0.17mL = X mL/hr 1 min min/hr X = 10ml/hr

12. Titrating IV Drugs Mostly seen in Critical care and/or OB
Started with bolus
Then increased to produce desired effect
Started at lowest dosage and increased or decreased as needed
Examples: Dopamine, Pitocin

13. Example: RL 1000mL with Magnesium Sulfate 20g
Example: RL 1000mL with Magnesium Sulfate 20g. Start with bolus of 4g for 30 min, then maintain continuous 2g/hr.
Step 1:Calculate bolus in g/mL: 20g = g 1000mL X mL X = 200mL should infuse over 30 min
Step 2:Calculate bolus in mL/hr 200mL = XmL/hr 30 min min/hr X = 400mL/hr
Step 3:Calculate continuous infusion rate by repeating steps 1 and 2 using 2 g instead of 4g.