Calculating IV Rate
  • Heparin dosing weight = IBW + (0.3 x (ABW-IBW)
  • Pharmacy will adjust weight for patients greater than 30% over IBW
Calculating Bolus
  • Heparin dosing weight equals IBW + (ABW-IBW) Max=5,000 units (typical limit).
  • Bolus does not have to be diluted.
  • Draw up Heparin from vile usually (1000 units per ml).
  • Pt must have an initial aPTT to start
  • Place order for repeat aPTT Q6 from the time you start the Heparin drip, not from when the order was placed.
  • Make sure the order is set as “Timed” not “Routine”
Cardiac Patient
  • If LESS THAN or EQUAL to 12 HOURS POST THROMBOLYTIC -DO NOT stop or decrease the infusion rate unless significant bleeding occurs or aPTT is greater than 170 seconds. if aPTT is below 50, adjust per nomogram.

Calculations based on 80 Kg. Calculations rounded to nearest 50 Units.

Heparin: 25,000 units diluted in 250 ml NSĀ  (1ml = 100 Units)

Initial rate: 18 Units/kg/hr = 1000 Units/hr

If aPTT less than 36: Bolus 60 Units/kg = 4,800 Units and Increase by 4 Units/kg/hr = 300 Units/hr (increase dose by 3ml)

If aPTT 36-45 seconds: Bolus 40 Units/kg = 3200 Units and Increase rate by 2 Units/kg/hr = 150 Units/hr (increase dose by 1.5ml)

If aPTT 46-60 seconds: NO BOLUS, and Increase rate by 2 Units/kg/hr= 150 Units/hr (increase dose by 1.5ml)

If aPTT 61-90 seconds: No Change

If aPTT 91-110 seconds: Decrease rate by 2 Units/kg/hr= 150 Units/hr

If Greater than 110 seconds: STOP infusing for 1 hr and Decrease rate by 4 Units/kg/hr= 300 Units/hr (decrease by 3ml)

Contacting Physician
  • Contact Physician when two consecutive aPTT >110 or <35.
  • Stop infusion and contact physician for any aPTT >140.
  • For signs of bleeding: Stop Infusion, order a stat aPTT and contact physician.