title: Letter: Prevention of deep-vein thrombosis.
mesh_terms: D002986:Clinical Trials as Topic; D003911:Dextrans / Q000008:administration & dosage / Q000627:therapeutic use; D004992:Ethics, Medical; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D007258:Informed Consent; D007263:Infusions, Parenteral; D007279:Injections, Subcutaneous; D008875:Middle Aged; D013924:Thrombophlebitis / Q000517:prevention & control*
chemical_list: D003911:Dextrans; D006493:Heparin