Machines designed to provide extracorporeal membrane oxygenation (ECMO) have been in use since the early 1970s—and are often associated with newborns in respiratory distress. But in an effort to save more lives, UCSF physicians have begun using the technology earlier and with a broader range of patients than in the past.
"ECMO itself is just a mechanical circulatory machine," notes Charles Hoopes, M.D.,; assistant professor of surgery at UCSF and director of the heart and lung transplant program at UCSF Medical Center. "What distinguishes our use of that technology is the patients we select and the point at which we choose to use it."
ECMO is a modified heart-lung machine that pumps and oxygenates a patient's blood, thus allowing the heart and lungs to rest. Traditionally, physicians have used it to provide cardiopulmonary support to patients recovering from lung failure, heart failure or surgery. But at UCSF, physicians also use the technology for rapid deployment salvage, in cases where patients have no other options. "They may have a devastating lung injury or heart failure, and this is their only hope," Hoopes says.
The survival rate for these salvage patients is 50 percent, so using the technology has been somewhat controversial. "We tend to deploy it very early in patients with lung failure," Hoopes says, "rather than waiting until a patient is dying. That means that some people end up having it who might have survived without ECMO. But it also means that people who would have died if we had waited longer end up living."
Using ECMO early also tends to save tissue from sustaining further hypoxic injury, which makes patients far better candidates for transplant, if that is what is deemed necessary. "If you wait until there's more injury, you end up with 15 to 18 percent higher morbidity down the line," Hoopes says.
The third use of ECMO is as a bridging option to further treatment, when physicians want to assess the state of other organs, including the brain and kidneys, before performing heart or lung surgery. "Basically, we buy ourselves 72 hours of not worrying about the heart and lungs," Hoopes says. "If we discover after 72 hours that extra-cardiopulmonary organs are still functioning, we can continue to perfuse them while fixing the heart problem. But if we discover the organs have been damaged, we'll take the patient off the machine."
The UCSF team has had especially good results in using ECMO to bridge patients awaiting lung transplants. "So far, we have found a donor organ in every case and have been able to send all our patients home," Hoopes says.
To contact Dr. Charles Hoopes, call (415) 353-1606.
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