Weight- Based Heparin Orders
For Deep venous Thrombosis (DVT) and Pulmonary Embolism (PE)
Obtain PTT, INR, CBC prior to initiating heparin.
Notify physician if platelet count is less than 100 K , hemoglobin drops by
more than 1 gram from baseline, or other abnormal values.
Dosing Weight = Actual Body Weight = ___________ kilograms
Initial heparin dosing:
(1) Give a bolus of 80 IU per kilogram =____________
(2) Start an infusion of 18 IU per kilogram per hour= ___________
(3) Order an aPTT 6 hours after heparin bolus given.
Initial heparin bolus (at 80 units/kg rounded to the nearest 100 units) =
________
Adjusting Infusion based on aPTT
| aPTT (Seconds) |
Bolus Dose IV | Hold
Infusion (minutes) |
Rate Change |
| < 35 s (<1.2 X control) |
80 units/ kg
=___________ |
0 | 4 units/kg/hr = ________ |
| 35 to 45 s (1.2 to 1.5 X control) |
40 units/ kg =_________ |
0 | 2 units/kg/hr =________ |
| 46 to 70 s (1.5 to 2.3 X control) |
0 | 0 | No change |
| 71 to 90 s (2.3 to 3 X control) |
0 | 0 | Decrease infusion
rate by 2 u/kg/hr =________ |
| > 90 s (> 3 X control) |
0 | 60 | Decrease infusion
rate by 3 u/kg/hr =________ |
Ongoing monitoring:
(1) Order an aPTT 6 hours after any dosage change.
(This interval approximates four half-lives of heparin, the time
required to achieve steady-state kinetics.)
(2) Once 2 consecutive aPTTs are within the therapeutic range, monitor the aPTT every 24 hours and adjust infusion accordingly.
REFERENCE: Raschke RA, Reilly BM, et al., The weight-based heparin dosing nomogram compared with a "standard care" nomogram. A randomized controlled trial. Ann Intern Med. 1993 Nov 1;119(9):874-81. PMID:8214998