2012 American College of Chest Physicians by Kimberly Henricks on February 10, 2012 chestjournal.chestpubs.org Downloaded from www.chestpubs.org CHEST / 141 / 2 / FEBRUARY, 2012 SUPPLEMENT e27S weight-based nomogram (starting dose, 80 units/kg bolus followed by 18 units/kg/h by infusion). Patients whose heparin was weight-adjusted received higher doses within the rst 24 h than those given xed doses of heparin. The rate of recurrent thromboem- bolism was significantly lower with the weight- adjusted heparin regimen. Initial dosing of IV heparin for VTE is either weight-based (80 units/kg bolus and 18 units/kg/h infusion49) or administered as a bolus of 5,000 units followed by an infusion of at least 32,000 units/d.51 If heparin is given subcutaneously for treatment of VTE, there are at least two options: (1) an initial IV bolus of 5,000 units followed by 250 units/kg twice daily52; or (2) an initial subcutaneous dose of 333 units/kg followed by 250 units/kg twice daily The doses of heparin recommended for treatment of acute coronary syndromes are lower than those used to treat VTE. The American College of Cardi- ology recommends a heparin bolus of 60 to 70 units/kg (maximum 5,000 units) followed by an infusion of 12 to 15 units/kg/h (maximum 1,000 units/h) for unsta- ble angina and non-ST-segment elevation myocardial infarction.53 Even lower doses of heparin are recom- mended when heparin is given in conjunction with brinolytic agents for treatment of ST-segment ele- vation myocardial infarction. Here, the bolus is about 60 units/kg (maximum 4,000 units) and the infusion is 1.1.4 Monitoring: The risk of heparin-associated bleeding increases with heparin dose55,56 and with concomitant administration of brinolytic agents57-60 or glycoprotein IIb/IIIa inhibitors.61,62 The risk of bleeding is also increased by recent surgery, trauma, invasive procedures, or concomitant hemo- static defects.63 In hospitalized patients, increasing number of comorbidities, age . 