Weight Based Heparin Protocol

OBPharmacopoeia^TM- Weight Based Heparin Dosing
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For Deep venous Thrombosis (DVT)and Pulmonary Embolism (PE)

Obtain PTT, INR, CBC prior to initiating heparin. Obtain platelet count on day 4 then every 3 days for two weeks.

Consider obtaining functional protein C, functional protein S, antithrombin III, factor V Leiden and prothrombin G20210A mutation analysis, anticardiolipin antibodies, and lupus anticoagulant .

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 = kg

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 80units/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 approximatesfour half-lives of heparin, the time required to achieve steady-statekinetics.)

(2) Once 2 consecutive aPTTs are within the therapeutic range, monitor the aPTT every 24 hours and adjust infusion accordingly.

All calculations must be confirmed before use. The suggested results are not a substitute for clinical judgment. Neither OBFocus.com nor any other party involved in the preparation or publication of this site shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.

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

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