A chemotherapy pump is a specialized medical device designed to deliver a controlled and steady amount of anti-cancer medication into a patient’s bloodstream over a set period of time. This precise delivery method is often necessary because some chemotherapy drugs must be infused slowly and continuously over many hours or even days to be most effective and minimize side effects. The term “chemo pump” refers to a category of systems that range in size from large hospital machines to small, wearable units. These devices ensure the medication flows consistently, preventing dangerous fluctuations in drug concentration that could occur with manual administration.
Stationary vs. Ambulatory Delivery Systems
The most immediate visual difference between chemotherapy pumps separates them into stationary and ambulatory systems. Stationary pumps are the larger, more complex units typically found within a hospital or infusion center setting. These devices are substantial electronic machines mounted on a wheeled pole, featuring a large screen for programming and complex control panels. They must be plugged into a wall outlet for continuous power, though they usually contain a battery backup to allow a patient to move short distances during the infusion session.
Ambulatory pumps, by contrast, are designed specifically for mobility, allowing a patient to receive treatment while at home or performing daily activities. These devices are significantly smaller, compact enough to be carried or worn, and are generally categorized by their power source or mechanism. Some ambulatory pumps are battery-operated, computerized devices, while others operate solely on mechanical pressure, similar to a balloon. The ability to leave the clinical environment with a pump attached provides flexibility and convenience for treatments that require continuous infusion over an extended period.
The Physical Appearance of Wearable Pumps
The appearance of wearable pumps varies mainly between computerized models and elastomeric models, both of which are small and lightweight. Computerized ambulatory delivery devices, or CADD pumps, are typically rectangular, hard-shell plastic units about the size of a small smartphone or pager. These pumps contain a digital interface for programming and are attached to a specialized cassette or bag that holds the chemotherapy drug. The pump and medication cassette are often secured together and placed inside a dedicated pouch or carrying bag, which the patient can wear on a belt or across the body.
The other common type is the elastomeric pump, which does not require batteries or complex programming, making it a simpler, disposable option. This device often looks like a small, rigid plastic container, sometimes described as resembling a small water bottle or a donut shape, which may have an amber tint to protect the medication from light. Inside this hard plastic casing is a flexible, balloon-like reservoir filled with the chemotherapy drug. The elastic tension of this inner balloon contracts slowly, providing the pressure needed to push the medication through the tubing at a preset rate.
A thin, clear extension tube extends from the pump’s reservoir to connect to the patient’s venous access site. A small, white section on this tubing, known as the flow restrictor, is a detail that must be kept at body temperature, often by being taped directly against the patient’s skin, to maintain the correct infusion speed. As the medication infuses, the balloon inside the elastomeric pump slowly deflates and begins to wrinkle, which provides a visual indicator that the pump is working. The entire unit, including the tubing, is usually carried in a small pouch or holster worn at the waist or over the shoulder.
Understanding Implanted Access Devices
All chemotherapy pumps, whether stationary or wearable, must connect to a vascular access device placed within the patient’s body for long-term treatment. One common type is the implanted port, also known as a Port-a-cath, which is a small, rounded reservoir with a rubber-like seal placed completely beneath the skin, typically in the upper chest area. When not in use, the port is only visible as a small bump under the skin, which can be easily covered by clothing. To administer the medication, a nurse inserts a specialized needle through the skin into the port’s seal, and the external pump tubing connects to this needle.
Another device is the Peripherally Inserted Central Catheter, or PICC line, which is a long, thin, flexible tube inserted into a vein in the arm. Unlike the port, the PICC line has an external portion of tubing that remains outside the body at the insertion site, usually secured to the arm with a dressing. The tubing from the external chemotherapy pump connects directly to the cap on this visible line. Both the port and the PICC line serve as the necessary, semi-permanent connection point for the pump, providing a reliable route for the chemotherapy to enter the bloodstream without repeated needle sticks.