title: New method to predict patients' intravenous heparin dose requirements.
abstract: OBJECTIVE
  To predict intravenous heparin dose requirements of patients treated for thromboembolic disorders.
  
  
  METHODS
  A retrospective cohort study in which we used simple linear regression to predict patients' effective maintenance dose (EMD) of heparin (units/kg/hour needed to achieve and maintain APTT therapeutic range) from patients' "heparin responsiveness" (the APTT increase after the initial 6 hours of heparin treatment per units/kg/hour received).
  
  
  METHODS
  The model was derived from 46 patients treated at one hospital (Hospital A) and then tested in 42 patients treated at another hospital (Hospital B).
  
  
  RESULTS
  Among Hospital A patients, there was a strong linear correlation (r = -.880; p < .001) between EMD (mean 16.02 units/kg/hour; 95% CI 14.9, 17.15) and "heparin responsiveness" (HR): EMD = 25.651 - [95.118 x HR]. This model accurately predicted Hospital B patients' EMD: 97% (37/38) fell within the model's 95% prediction interval; the mean absolute difference between predicted and actual EMD was 1.73 units/kg/hour (95% CI 1.39, 2.08); and only 16% of patients had EMD's more than 3 units/kg/hour different from that predicted by the regression model. The model's accuracy was comparable to that of our gold standard, the weight-based heparin dosing nomogram.
  
  
  CONCLUSIONS
  The infusion dose of intravenous heparin effective for an individual patient can be predicted accurately from the patient's body weight and APTT response to the initial 6 hours of treatment. Especially in hospitals where validated heparin dosing nomograms are not used, clinicians may find this simple technique useful in achieving timely therapeutic anticoagulation.
authors.affiliation: Department of Medicine, Cook County Hospital, Chicago, IL 60612, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Reilly
authors.forename: R A
authors.initials: RA
authors.lastname: Raschke
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D016014:Linear Models; D010314:Partial Thromboplastin Time; D012189:Retrospective Studies; D013923:Thromboembolism / Q000188:drug therapy*
chemical_list: D000925:Anticoagulants; D006493:Heparin