Life support, in the meical field, refers to a set of therapies for preserving a patient's life when essential body systems are not functioning sufficiently to sustain life unaided. Life support therapies utilize some combination of several techniques: feeding tubes, intravenous drips, total parenteral nutrition, mechanical respiration, heart/lung bypass, urinary catheterization and dialysis. The same techniques are also used for intensive care or in some cases during surgery, though life support is employed to stabilize a patient and is typically not sufficient to allow full recovery from their condition.