Verstraete M
Surg Gynecol Obstet. 1976 Dec;143(6):981-5.
The standard low dose of heparin for the prevention of deep venous thrombosis in patients who are operated upon is 5,000 units administered subcutaneously two hours before operation and at eight or 12 hourly intervals for the next seven days. Heparin in low doses can at present be recommended as an effective agent in the prevention of deep venous thrombosis in patients over the age of 40 years who are undergoing a major abdominothoracic or gynecologic operation. There is reasonable evidence that heparin in low doses also offers a satisfactory protection against fatal pulmonary embolism for patients at high risk after general abdominothoracic operations. The evidence of the effectiveness of low doses of heparin in the prevention of deep venous thrombosis is less well established in other patients and particularly those at high risk, as after urologic and hip operations. This important distinction is to be made in terms of the population at risk and the efficacy of heparin in low doses. Considering the evidence so far available, it appears that the postoperative state in which dextran has been shown to reduce the incidence of phlebographically confirmed deep venous thrombosis most convincingly is after orthopedic operations. Major orthopedic operations are precisely the type in which the superiority of heparin in low doses is controversial. Unless proved otherwise, dextran 70 in an infusion of 500 to 1,000 milliliters of a 6 per cent solution started before operation and 500 milliliters the following and next three alternate days may be the agent of choice in preventing deep venous thrombosis in major orthopedic operations. Using this scheme, the prophylaxis of postoperative deep venous thrombosis appears equally effective with dextran 70 as with oral anticoagulants. Whether the protection offered by dextran 70 will also prevent fatal and nonfatal pulmonary embolism is still an open question. Low doses of heparin and dextran do not expose patients to serious risks of bleeding after operation, and with the recommended doses of the latter drug, other untoward effects are rare. At the doses recommended, neither of these two drugs requires laboratory monitoring.
用于预防手术患者深静脉血栓形成的标准低剂量肝素是术前两小时皮下注射5000单位，并在接下来的七天内每隔八小时或十二小时注射一次。目前，低剂量肝素可被推荐为预防40岁以上接受大型腹部、胸部或妇科手术患者深静脉血栓形成的有效药物。有合理证据表明，低剂量肝素对接受普通腹部、胸部手术后的高危患者预防致命性肺栓塞也有令人满意的效果。低剂量肝素预防深静脉血栓形成有效性的证据在其他患者中，尤其是高危患者中，如泌尿外科手术和髋关节手术后的患者中，尚不充分。这一重要区别应根据高危人群以及低剂量肝素的疗效来判断。根据目前可得的证据，右旋糖酐最能令人信服地降低经静脉造影证实的深静脉血栓形成发生率的术后状态似乎是在骨科手术后。大型骨科手术正是低剂量肝素优势存在争议的手术类型。除非另有证明，术前开始输注500至1000毫升6%溶液的右旋糖酐70，随后及接下来的三个隔日各输注500毫升，可能是预防大型骨科手术深静脉血栓形成的首选药物。采用该方案，右旋糖酐70预防术后深静脉血栓形成的效果与口服抗凝剂相当。右旋糖酐70提供的保护是否也能预防致命性和非致命性肺栓塞仍是一个悬而未决的问题。低剂量肝素和右旋糖酐不会使患者术后面临严重出血风险，按照推荐剂量使用后一种药物，其他不良反应也很少见。按照推荐剂量，这两种药物都不需要实验室监测。
