An oxygenator, also called a membrane oxygenator, is a crucial part of the heart-lung machine system. Its function is to take over the workload of the lungs during cardiopulmonary bypass (CPB) surgery. The device is operated by a perfusionist, and serves to remove carbon dioxide and add oxygen to the blood while the patient in under anesthetic. After the impurities in the blood are extracted, the clean, or red blood, is pumped back into the patient. Another device called the heparin-coated oxygenator can also be used during CPB, and is thought to lessen inflammation as well as the potential for blood clots within the system.
The machine essentially takes over the function of the lungs, but it can also act as a more sustained life-support system by continuing to oxygenate the blood after the surgery. This is called extracorporeal membrane oxygenation. The oxygenator system is often employed by staff in neonatal intensive care units to assist newborns that are in critical condition. Inside the machine is a very thin, absorbent membrane that separates the blood and gas, and allows the impurities, such as carbon monoxide, to leach away into the gas for disposal. The oxygenator component can be used for several days and is then thrown away.
The heart-lung machine, of which the oxygenator is one component, is essentially a device that continues the flow of blood and oxygen during an operation where the heart function has been artificially ceased. Potassium citrate is pumped through the coronary system to stop the heart’s contractions. This allows the doctor to perform surgery while the organ is devoid of blood and oxygen. There are some instances when surgeons are able to perform open heart surgery when the heart is actually still beating.
Perfusionists, sometimes known as the “pump team”, operate the oxygenator and are crucial to the successful outcome of CPB. These specialists are also tasked with monitoring blood cell count and circulation during surgery. An anesthesiologist may direct the perfusionist to administer medication through the oxygenation system during certain critical phases of the operation. The perfusionist is a vital part of the heart surgery team and experienced technicians are in great demand.
The heart-lung machine was first used on a human being in 1953 and only had two permanent components; the oxygenator and pump. Because of the costs involved, disposable parts were eventually introduced by the end of the 1950s. Heart-lung machines are used during all cardiopulmonary bypass surgeries and have been partly responsible for saving many lives.