Ultrafast freezing of the embryos of outbred and inbred mouse strains

Prophylaxis of postoperative thromboembolism is widely used because it has been shown to save lives and money. However, some surgeons are still reluctant to use general prophylaxis in high-risk orthopedic surgery. In total hip and total knee replacement the best method of prophylaxis is currently low molecular weight heparin started preoperatively and continued for 7 to 14 days or until the patient is fully ambulatory. A shorter prophylaxis period failed to be effective in an English study. At present there is an ongoing debate on the length of the period of risk, and whether there is a need for prophylaxis after discharge. Oral anticoagulation has been used for extended prophylaxis, but studies show that anticoagulant levels need to be monitored by repeated measurements by international normalized ratio. An alternative method would be to continue low molecular weight heparin injections for 4 to 5 weeks after surgery. No studies so far have evaluated the efficacy and safety of prolonged prophylaxis with low molecular weight heparin after discharge.