Achievement of anticoagulation by using a weight-based heparin dosing protocol for obese and nonobese patients

The need for different heparin dosing protocols for obese and nonobese pati ents was studied. A chart review was performed for all patients who received heparin over an eight-month period at an acute care hospital. Data collected included age, sex, height, actual body weight (ABW), ideal body weight (IBW), initial act ivated partial thromboplastin time (aPTT), initial heparin bolus dose, init ial heparin i.v. infusion rate, time to initial targeted aPTT, and final in fusion rate. Forty patients met criteria for inclusion: 20 obese patients (greater than 30% over IBW) and 20 nonobese patients (less than 20% over IBW). Mean +/- S .D. initial heparin infusion rates for the obese and nonobese groups were 1 4.44 +/- 1.29 and 15.04 +/- 0.42 units/kg/hr, respectively. Times to target ed aPTT for obese and nonobese patients were 25.86 =/- 12.83 and 25.18 +/- 14.76 hours, respectively; mean final infusion rates were 12.94 +/- 2.56 an d 12.36 +/- 2.54 units/kg/hr; and percent changes from initial to final inf usion rates were 11.84% and 17.76%. There were no significant differences i n initial or final infusion rates or time to targeted aPTT between the two groups. It is appropriate to use ABW in a weight-based heparin dosing protocol for obese patients.