The blood pump is a medical device for pumping blood, using a system known as a roller or peristaltic pump that works by squeezing tubing to force blood through. Early versions of this device date to the middle of the 19th century. Today, people use blood pumps for cardiopulmonary bypass, some transfusion procedures, and supporting patients in heart failure. Many medical device manufacturers produce blood pumps and accessories.
Pumping blood presents a number of challenges, including the desire to maintain a consistent rate of flow and the need to keep it wholly sterile. The blood pump uses lines of tubing with no seals, gaskets, and other weak points. Rollers compress and release the tubing to force the blood through, a method known as peristalsis. This mimics some internal processes; the intestines work in the same way, for example.
The blood pump controls the flow of blood under the direction of the operator, keeping it consistent and regular. After use, the technician can remove the tubing and replace it when necessary for another procedure, maintaining sterility and reducing the risk of passing infections between patients. Similar pump designs are also available for activities like infusions, where doctors pass fluids through a roller pump on their way to the patient to provide patients with pain management, medications, nutrients, and other needs.
One of the most common applications is in cardiopulmonary bypass, using the heart-lung machine to replace the function of the heart and lungs while a patient is in surgery. Rerouting the blood allows a surgeon to work in a clean field and expands the number of procedures a doctor can perform. In this case, the blood pump circulates fluid extracorporeally during the procedure, under the supervision of a technician. When the surgeon is ready, the technician can take the patient off bypass and allow the heart and lungs to take over. Invention of bypass was a significant development in cardiothoracic surgery.
The blood pump also has applications for supporting the heart of a patient in heart failure. When the heart can no longer pump on its own, extracorporeal circulation may be a temporary solution to support the patient through treatment or while waiting for a donor organ. It requires a significant commitment to care on the part of patients and family members, and is not a widespread practice. Development of smaller pumps, including wearable units, could make this option more widely available.