Membrane oxygenator
Encyclopedia
A membrane oxygenator is a device used to add oxygen to, and remove carbon dioxide from the blood. It can be used in two principal modes: to imitate the function of the lung
s in cardiopulmonary bypass (CPB), and to oxygenate blood in longer term life support, termed extracorporeal
membrane oxygenation, ECMO. A membrane oxygenator consists of a thin gas permeable membrane separating the blood and gas flows in the CPB circuit; oxygen diffuses from the gas side into the blood, and carbon dioxide diffuses from the blood into the gas for disposal.
in the USA demonstrated the feasibility of extracorporeal oxygenation. Brukhonenko used excised dog lungs while Gibbon used a direct contact drum type oxygenator, perfusing cats for up to 25 minutes in the 1930s
Gibbon’s pioneering work was rewarded in May 1953 with the first successful cardiopulmonary bypass operation . The oxygenator was of the stationary film type, in which oxygen was exposed to a film of blood as it flowed over a series of stainless steel plates.
The disadvantages of direct contact between the blood and air were well recognized, and the less traumatic membrane oxygenator was developed to overcome these. The first membrane artificial lung was demonstrated in 1955 by the group led by Willem Kolff and in 1956 the first disposable membrane oxygenator removed the need for time consuming cleaning before re-use . No patent was filed as Kolff believed that doctors should make technology available to all, without mind to profit.
The early artificial lungs used relatively impermeable polyethylene
or Teflon homogeneous membranes, and it was not until more highly permeable silicone rubber
membranes were introduced in the 1960s (and as hollow fibres in 1971) that the membrane oxygenator became commercially successful . The introduction of microporous hollow fibres with very low resistance to mass transfer revolutionized the design of membrane modules, as the limiting factor to oxygenator performance became the blood resistance . Current designs of oxygenator typically use an extraluminal flow regime, where the blood flows outside the gas filled hollow fibers, for short term life support, while only the homogeneous
membranes are approved for long term use.
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s in cardiopulmonary bypass (CPB), and to oxygenate blood in longer term life support, termed extracorporeal
Extracorporeal
An extracorporeal medical procedure is a medical procedure which is performed outside the body.-Circulatory procedures:A procedure in which blood is taken from a patient's circulation to have a process applied to it before it is returned to the circulation...
membrane oxygenation, ECMO. A membrane oxygenator consists of a thin gas permeable membrane separating the blood and gas flows in the CPB circuit; oxygen diffuses from the gas side into the blood, and carbon dioxide diffuses from the blood into the gas for disposal.
History
The history of the oxygenator, or artificial lung, dates back to 1885, with the first demonstration of a disc oxygenator, on which blood was exposed to the atmosphere on rotating discs by Von Frey and Gruber These pioneers noted the dangers of blood streaming, foaming and clotting. In the 1920s and 30s, research into developing extracorporeal oxygenation continued. Working independently, Brukhonenko in the USSR and John Heysham GibbonJohn Heysham Gibbon
John Heysham Gibbon Jr., AB, MD, a surgeon best known for inventing the heart-lung machine and performing the first open heart surgery . He was the son of Dr...
in the USA demonstrated the feasibility of extracorporeal oxygenation. Brukhonenko used excised dog lungs while Gibbon used a direct contact drum type oxygenator, perfusing cats for up to 25 minutes in the 1930s
Gibbon’s pioneering work was rewarded in May 1953 with the first successful cardiopulmonary bypass operation . The oxygenator was of the stationary film type, in which oxygen was exposed to a film of blood as it flowed over a series of stainless steel plates.
The disadvantages of direct contact between the blood and air were well recognized, and the less traumatic membrane oxygenator was developed to overcome these. The first membrane artificial lung was demonstrated in 1955 by the group led by Willem Kolff and in 1956 the first disposable membrane oxygenator removed the need for time consuming cleaning before re-use . No patent was filed as Kolff believed that doctors should make technology available to all, without mind to profit.
The early artificial lungs used relatively impermeable polyethylene
Polyethylene
Polyethylene or polythene is the most widely used plastic, with an annual production of approximately 80 million metric tons...
or Teflon homogeneous membranes, and it was not until more highly permeable silicone rubber
Silicone rubber
Silicone rubber is an elastomer composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations...
membranes were introduced in the 1960s (and as hollow fibres in 1971) that the membrane oxygenator became commercially successful . The introduction of microporous hollow fibres with very low resistance to mass transfer revolutionized the design of membrane modules, as the limiting factor to oxygenator performance became the blood resistance . Current designs of oxygenator typically use an extraluminal flow regime, where the blood flows outside the gas filled hollow fibers, for short term life support, while only the homogeneous
Homogeneous (chemistry)
A substance that is uniform in composition is a definition of homogeneous. This is in contrast to a substance that is heterogeneous.The definition of homogeneous strongly depends on the context used. In Chemistry, a homogeneous suspension of material means that when dividing the volume in half, the...
membranes are approved for long term use.
External links
- Oxygenator summary in Cardiac Surgery in the Adult