An Extracorporeal Membrane Oxygenation (ECMO) machine is a medical device that performs this task. In fact, it is very similar to a heart-lung machine that is used to continue the supply of blood and oxygen while the heart is stopped, such as during open heart surgery. ECMO therapy, however, is intended for patients whose heart and lungs cannot normally function on their own.
Patients receive ECMO in the intensive care unit of a hospital, where medical personnel specially trained in respiratory therapy can continuously monitor them. The process begins with dispensing an anticoagulant to the patient to minimize clotting of the blood. This is necessary because the patient’s blood must pass through a tube to the ECMO machine where it can be oxygenated by an artificial lung and be returned. The machine further simulates human respiration by removing carbon dioxide from the blood. The patient remains placed on the machine until his or her own heart and/or lungs can resume normal functioning.
The additional acronyms of VV and VA are used to differentiate between the two main methods of administering ECMO therapy. VV stands for veno-venous and indicates that the mode of entry into the body is a vein. This is usually the preferred method when the patient has suffered the loss of lung function exclusively. In contrast, veno-arterial, or VA, means that dual access by a vein and the carotid artery is necessary, and usually applies to patients with both lung and heart impairment.
While many patients receive this type of therapy due to advance disease or damage to the heart and/or lungs, it also has an application in neonatal emergency medicine. In fact, use of the EMCO machine in children’s hospitals has saved many full-term infants with pulmonary or respiratory distress that fails to respond to other interventions. On occasion, EMCO therapy may also be given to premature infants born with underdeveloped lungs or other birth defect. Unfortunately, it cannot be safely used on premature infants weighing less than 4.5 pounds (2.04 kilograms).
While ECMO is indeed lifesaving in many cases, there are certain risks associated with this therapy. For one thing, there is always a risk of infection at the access site, which may necessitate a regimen of antibiotics. The formation of air bubbles or blood clots in the tubing also presents a risk. Also, the fact that anticoagulant drugs are given to prevent clotting poses an additional risk of excessive bleeding. Finally, patients who undergo VA ECMO may have an increased risk of stroke.