Limb perfusion is a medical procedure used to deliver medication to a specific site in the body, usually an arm or leg affected by cancer. It's purpose is to deliver a very high dose to that specific site where delivering the same concentration throughout the body would likely be fatal. It is often used as part of a chemotherapy regimen.
The first step is to use a tourniquet to restrict the flow of blood to the target limb. The blood supply for the limb is then provided externally through a circuit of tubes, pumps and heat exchangers. Once this is set up, the drug is injected directly into the blood supply at the limb at 42 Celcius. This speeds the uptake of the drug into the tumor being treated.
The procedure is relatively safe, but it can cause a thrombosis if a vein is used repeatedly, although the thrombosis is usually not very dangerous. However, the waste products of the procedure are very toxic and require careful disposal and handling.