|An infant benefits from the extracorporeal membrane oxygenation (ECMO) life support system, which was developed at the U-M in 1980. ECMO allows a patients heart and lungs to recover by pumping and oxygenating the blood. Photo by Bill Wood, U-M Photo Services|
U-M researchers have released a detailed portrayal of the evolution of that life support system, known alternately as extracorporeal membrane oxygenation (ECMO) or extracorporeal life support (ECLS). It is performed by a modified heart-lung machine that allows a critically ill patients heart and lungs to rest and recover while the device pumps and oxygenates their blood.
The researchers studied the first 1,000 patients who were treated with ECMO since the U-M founded its Extracorporeal Life Support Program in 1980. They found that survival rates for patients gravely ill with respiratory failure was 88 percent for neonates, 70 percent for children and 56 percent for adults. For patients who were considered near death with cardiac failure, the survival rates were 48 percent for children and 33 percent for adults.
The only time we use ECMO is for patients who we all agree have little or no chance of surviving their acute illness with other available conventional techniques, says Robert Bartlett, professor of surgery and developer of the ECMO system. So, basically all the patients who are treated with ECMO, if they survive, have been saved or have had their lives prolonged by the device because our best information is that they likely would have died without it.
The study also details how the U-M pioneered, developed and advanced ECMO to the point where it has now expanded to worldwide use. Currently, 120 centers participate in the Registry of the Extracorporeal Life Support Organization, all of which stem from the U-M program. The registry of all patients in the world treated with ECMO is kept at the U-M and medical experts from around the world travel to Ann Arbor annually to compare and learn the latest techniques.
While its origin lies in the heart-lung machine, the system used for ECMO differs in many ways. ECMO can be used for much longer periods of timemore than a month if needed, and the pumps, artificial lungs and, most importantly, the hookups are also different. The patient is attached through large blood vessels in the neck and leg, avoiding the need to open his or her chest. ECMO is also quite different than a ventilator.
A ventilator breathes for the patient, Bartlett explains. It blows gasses into the patients lungs and they come out. ECMO, on the other hand, takes over the exchange of oxygen and carbon dioxide, but it does not rely on the patients lungs to do so. It doesnt involve breathing through the mouth or airwayit deals directly with the blood.
ECMO is portable, allowing patients to be moved throughout the hospital. This also allows for long distance treatment of patients.
Many of the patients who are considered for ECMO and referred to the U-M are too sick to be moved here, Bartlett says. We have learned to take the machine to the patient, put them on ECMO in the referral hospital and when theyre stabilized, bring them to the U-M for treatment in better condition.
Bartlett began early work that would lead to ECMO prior to coming to the U-M. It really started with heart surgery, he says. In the early days of heart surgery in the 1960s, the heart-lung machine was just beginning to be used and it was clear that patients who were treated with it for heart operations often developed heart failure or lung failure after those operations. The initial concept was to modify the machine to keep those patients alive for a longer time so they might recover. We brought the idea to the U-M where it has grown from a laboratory curiosity into full clinical use.
ECMO was originally used primarily in cases of neonatal respiratory failure and showed early success. Bartlett attributes this to the fact that neonatal lungs are basically normal and recover quickly. The success in treating neonates prompted further research that led to treatment in children and adults.
What does the future hold for ECMO? Bartlett thinks its success may mean its decline in use.
The future of this technology is that for most patients, it will not be needed at some time in the distant future, he says. The use of ECMO has allowed us to learn much about recovery of the heart or lungs from serious illnessthings we could not learn before because the patient died. Weve also been able to learn a lot about treatment of heart failure and lung failure that would not have been previously possible for the same reason. This knowledge, made possible by ECMO, allows us to prevent the very serious progression of these problems and often prevent the patient from needing ECMO. Its sort of like dentists and the use of fluoride. If we get really good at it, we wont need it.