A hepatic arterial infusion pump (HAI pump) is an implantable device approximately the size of a hockey puck. The pump delivers chemotherapy through a specialized infusion system at a constant rate to the liver. This allows for much higher doses than with standard systemic chemotherapy. The HAI pump is used to treat colorectal liver metastases.

The HAI pump is a fully implanted system. A catheter that connects to the pump via the hepatic artery is implanted under the skin (percutaneously). Because liver tumors thrive on highly oxygenated blood from the hepatic artery, responsible for 80% or more of their blood supply, there is a very significant adverse cytotoxic effect on the tumor. HAI also has fewer side effects because the chemo does not circulate throughout the body. The pump is periodically refilled with chemotherapy.