Extracorporeal membrane oxygenation

The extracorporal membrane oxygenation (ECMO ) and extracorporeal lung assist (ECLA ) is an intensive medical technique in which a machine takes over part or all of the respiratory function of patients. It is used in patients whose lungs are damaged severely no longer allow ( ARDS) and the gas exchange in the measurement, to ensure the respiratory function. It is often used in neonates who have damaged lungs ( respiratory distress syndrome, meconium aspiration, persistent pulmonary hypertension) or certain congenital heart defects.

The ECMO is thus a form of extracorporeal organ replacement procedures and is also referred to as Extra Corporeal Life Support ( extracorporeal life support, ECLS ).

ECMO can ensure adequate oxygenation for days or weeks and is thus the time of the lung, with no cure aggressive resuscitation. Nevertheless, the ECMO is because of the high technical and personnel requirements, costs and risk of complications (eg, bleeding ) is considered as a last therapeutic option ( last resort ).

Technology

Technically similar to an ECMO device to a heart - lung machine. To include ECMO, cannulae are placed in two large blood vessels. To prevent clotting, is given to anticoagulant agents ( anticoagulants ) to, usually heparin. The ECMO machine continuously pumps blood through a membrane oxygenator, the gas exchange in the lungs replaced: it removes carbon dioxide from the blood and enriches it with oxygen. The conditioned blood is then returned to the patient.

Currently, the ECMO is operated manually set as therapy, in which a physician or perfusionist prescribes the necessary control values ​​. As the subject of several research projects, a patient- controlled ECMO is worked out individually.

Variants of the ECMO

There are several forms of ECMO, the most important are the Veno - Venous ECMO ( VV ECMO), the veno - arterial ECMO (VA - ECMO) and the arterio - venous pumpless ECLA ( PECLA ). Is taken from the blood in the first two versions of large veins (eg femoral vein or internal jugular vein ). Wherein VV ECMO, the oxygenated blood is then re-introduced into a vein, it is indicated in severe respiratory failure with still sufficient function of the heart. In VA ECMO, however, the blood to the heart over an artery (arteria femoralis ) is passed, so that a parallel circuit. Because that makes the heart is relieved, this method is used in patients with poor pumping function of the heart ( cardiac insufficiency). The PECLA is used in patients with Adequate cardiac function, which require less support in gas exchange. Since no pump is used there will be a lower blood damage in the PECLA in general.

ECMO in adults

The first application of cardiopulmonary bypass for the treatment of respiratory failure ( ARDS) took place in the early 1970s. With the prospect of an effective therapeutic tool for the treatment of ARDS, the National Institutes of Health launched ( Supreme Health Agency) ARDS multicenter study. The results were sobering: The group with ECMO treatment showed a better treatment outcome, the study was terminated prematurely. The study was a setback for the ECMO development despite methodological shortcomings. The research focused on as a result, re- amplified to improve the conventional method of ventilation.

Only in the 1980s succeeded in an Italian research group with improved methods to show a benefit of ECMO, but in a non- controlled study. To date, the result of these and other follow-up studies is that ECMO may be in ARDS in adults of benefit, but so far without being able to prove a significant advantage over a ventilation therapy. 2006, a randomized multicenter trial was stopped with 80 centers and 180 patients to determine the significance of ECMO for ARDS therapy in the UK. Published preliminary results seem to be favorable for the use of extracorporeal membrane oxygenation during respiratory failure in adults.

The first successful application of extracorporeal gas exchange ( ECMO, ELA, ECLA, ECCO2 R) in Germany were in acute respiratory failure in adults in the years 1971 and 1983 at the University of Dusseldorf, as well as in burns for the first time in 1975 by Rommelsheim and Birtel at the Department of Anaesthesiology, University of Bonn conducted.

ECMO in the newborn

Bartlett reported in 1975 the first successful neonatal ECMO application in California. This was followed by the first pioneering study that showed an increased survival by treatment. This compared to adults significantly better response for ECMO therapy in the newborn led to an increasing number of ECMO treatment cases and ECMO centers, first in the USA and later around the world.

In February 1987, the first successful ECMO application was carried out in a newborn in the German-speaking area in the Mannheim Children's Hospital. 1994-1995, a randomized multicenter study was performed in newborns in the UK. Due to the significantly higher survival rate in the ECMO treatment group, the study was stopped early in November 1995, as the continuation was not ethically justifiable. The study also refuted in subsequent follow-up studies, the fear that the higher survival rate would be "bought" in the ECMO treatment group by psychomotor deficits. Instead, the use of ECMO is maintained in the follow-up of children.

Extracorporeal Life Support Organization ( ELSO )

In 1989 a central ECMO register in Ann Arbor, Michigan ( USA) was established. There ECLS applications are centrally recorded and broken down in detail. This allows a detailed overview of the effectiveness and the number of cases the course of therapy in certain diseases. As a result, therapy-specific improvements or problems in the area ECLS applications are rapidly detected and passed on to other ECMO centers. By the end of 2012, more than 53,000 ECLS applications of the Extracorporeal Life Support Organization ( ELSO ) have been reported and statistically analyzed worldwide. Currently (as of January 2013) are the ELSO reported 200 active ECMO centers worldwide.

Possible complications during therapy

ECMO is used nowadays As already mentioned only as Ultima Ratio therapy due to various factors. One of these factors are the various possible during ECMO treatment complications. These include the suction of the collection cannula to the blood vessel wall, a displacement of the cannula, a defect of the blood pump used or an air embolism.

The treatment and the early detection of these complications is the subject of current research projects. These works are all still in preclinical stages.