Heparin Dosing for Nursing Example Calculation 6/1/2015 Jennifer Cook
Weight-Based Heparin Protocol: Heparin IV infusion: Heparin 25,000 units in 250 mL of ½ NS IV Boluses: Use Heparin 1,000 units/mL Calculate the Patient’s weight in kg. Weight: _________ kg. Bolus with Heparin 80 units/kg. Then initiate Heparin drip at 18 units/kg/h. Obtain aPTT q 6 hours, and adjust dosage and rate as follows: If aPTT is less than 35 seconds: Rebolus with 80 units/kg and increase rate by 4 units/kg/h. If aPTT is less than 36 to 44 seconds: Rebolus with 40 units/kg and increase rate by 2 units/kg/h. IF aPTT is 45 to 75 seconds: Continue current rate. If aPTT is 76 to 90 seconds: Decrease rate by 2 units/kg/h. If aPTT is greater than 90 seconds: Hold heparin for 1 hour and then decrease rate by 3 units/kg/h.
Follow a Patient through Heparin Dosing and Correct Heparin Dosing Adjustments (per Standard Weight-Based Heparin Protocol Table) according to aPTT results.
Problem/s: Information - Patient’s weight is: 165 lbs.
Set # 1 Convert the patient’s weight to kg: 75 kg. 165 đ?‘™đ?‘?đ?‘ 2.2
= 75 kg (REMEMBER: 1 lb = 2.2 kg)
Calculate the Initial Heparin Bolus dosage: 6,000 units. Table above says Bolus w/Heparin 80 units/kg, so what are we looking for? Units.
80 units =kg = 80 x 75 = 6,000 units
75 kg
Calculate the Bolus Dose: 6 mL Table above says: IV Boluses: Use Heparin 1,000 units/mL. What are we looking for? mL. 1 mL 1,000 units
=
6,000 đ?‘šđ??ż 1,000
6,000 units
= 6 mL
Calculate the Initial Heparin Infusion Rate: 1,350 units/h Patient’s weight is still 75 kg. Table says Initial Heparin Infusion Rate is 18 units/kg/h, so what are we looking for? Units/h. 18 units kg/h = 18 x 75 = 1,350 units/h
75 kg
Calculate the Initial Heparin Infusion Rate: 14 mL/h Table says 25,000 units per 250 mL of fluid. It also says initiate Heparin drip at18 units/kg/h and the patient’s weight in kg is 75 kg. You have to set the problem up to cancel out like units and leave what we are looking for, which is mL/hr. 250 mL 25,000 units
=
337,500 đ?‘šđ??ż
25,000 đ?‘˘đ?‘›đ?‘–đ?‘Ąđ?‘
18 units kg/hr
75 kg
= 13.5 mL/h or rounded up to 14 mL/h
Set # 2 At 0900, the patient’s aPTT is 33 seconds. According to the protocol, what will your action be? Rebolus with 6,000 units, or 6 mL. Again, table says to Rebolus with 80 units/kg or 1,000 units/mL. 80 units kg = 80 units x 75 = 6,000 units
75 kg
1 mL 1,000 units
=
6,000 đ?‘šđ??ż 1,000
6,000 units
= 6 mL
Increase infusion rate by 300 units/h, or 3 mL/h, for a new rate of 17 mL/h. Table says for aPTT of 33 seconds, to increase the rate by 4 units/kg/h. What are we looking for? Units/h. 4 units kg/h 4 units x 75 = 300 units/h
75 kg
Or Table says there are 25,000 units per 250 mL, so what are we looking for? mL/h. 250 mL 25,000 units
=
750 đ?‘šđ??ż 250
300 units 1h
= 3 mL/h
Then, just add 3 mL/h to the original 14 mL/h for a total of 17 mL/h for the New Infusion Rate.
Set # 3 At 1500, the patient’s aPTT is 40 seconds. According to the protocol, what will your action be? Rebolus with 3,000 units, or 3 mL. Again, table says to Rebolus with 40 units/kg or 1,000 units/mL. 40 units kg = 40 units x 75 = 3,000 units 1 mL 1,000 units
=
3,000 đ?‘šđ??ż 1,000
75 kg
3,000 units
= 3 mL
Increase infusion rate by 150 units/h, or 1.5 mL/h, for a new rate of 19 mL/h. Table says for aPTT of 33 seconds, to increase the rate by 2 units/kg/h. What are we looking for? Units/h.
2 units kg/h 2 units x 75 = 150 units/h
75 kg
Or Table says there are 25,000 units per 250 mL, so what are we looking for? mL/h. 250 mL 25,000 units
=
3,750 đ?‘šđ??ż 2,500
150 units 1h
= 1.5 mL/h
Then, just add 1.5 mL/h to the last mL/h dose of 17 mL/h for a total of 18.5 mL/h rounded up to 19 mL/h (must be in whole drops) for the New Infusion Rate.
Set # 4 At 2100, the patient’s aPTT is 60 seconds. Look at the table. What will your action be according to the protocol? Continue current rate.