New Method Might Raise Number of Donor Lungs12/14/10
TUESDAY, Dec. 14 (HealthDay News) -- A change in medical
procedures could greatly reduce and possibly eliminate the shortage
of lungs available for transplant, U.S. experts and an Italian
The procedure -- carefully controlling the volume of air and
pressure inside the lungs of brain-dead patients on ventilators --
nearly doubled the number of lungs that were able to be
transplanted to save the lives of others, the study found.
The United States has a shortage of lungs, as well as other
organs, available for donation. People needing a lung transplant
wait an average of more than three years, according to the United
Network for Organ Sharing (UNOS). In 2009, 2,234 people were added
to the waiting list, according to the Organ Procurement and
Transplantation Network (OPTN).
One reason for the shortage is that lungs are "finicky" and
easily damaged while comatose patients are on ventilators, said Dr.
Phillip Camp, director of the lung transplant program at Brigham
and Women's Hospital in Boston and chairman of the UNOS-OPTN
operations and safety committee.
But more carefully controlling how much air is pushed into the
lungs by ventilators and maintaining pressure inside the lungs
during such procedures as apnea tests, to check breathing, improves
lung viability dramatically, according to the study.
"They found remarkable increases in the availability of viable lungs using this lung preservation strategy," said Dr. Mark S. Roberts, chairman of the health policy and management department at the University of Pittsburgh and author of an editorial accompanying publication of the study in the Dec. 15 issue of the Journal of the American Medical Association.
The study involved 118 brain-dead patients with otherwise normal
lung function. One group was given conventional ventilation,
including relatively high volumes of air pumped in from the
ventilator and disconnection of the ventilator during apnea tests,
allowing the lungs to deflate.
The others were given so-called "protective" ventilation. That
procedure included less air volume, higher "positive end-expiratory
pressure levels," which meant increasing the air pressure in the
lungs near the end of expiration to maintain pressure, and the use
of continuous positive airway pressure during various medical
procedures and tests, which does not allow the lungs to totally
About 95 percent of those in the protective ventilation group
met the criteria to become lung donors, compared with 54 percent of
those treated conventionally.
About 54 percent of the protective group actually became donors,
compared with 27 percent in the conventional group.
Those who received the donor lungs showed little difference in
outcomes. After six months, 75 percent of people who'd received a
lung from the protective group were alive, compared with 69 percent
who'd gotten a lung from the conventional group.
The number of other organs -- such as hearts, livers or kidneys
-- donated by each person was also similar, regardless of which
method of ventilation had been used.
Small studies in the United States have tried similar strategies
successfully, Camp said.
During normal respiration, the diaphragm contracts, allowing a
person to suck air into the lungs using a negative pressure system,
Camp explained. Ventilators, on the other hand, force air into the
lungs using positive pressure. Over time, much like blowing up a
balloon again and again, that process can weaken and damage the
lungs, he said.
But lowering the volume pushed into the lungs seems to help
avoid some of this damage, Camp said.
Also, during conventional ventilation, the ventilator is turned
off briefly during certain medical tests and procedures, allowing
the lungs to essentially deflate. Like blowing up a balloon,
getting them re-inflated requires forcing air into the lungs, which
also takes a toll, Camp said.
Maintaining a low level of air pressure in the lungs at all
times avoids this, he said.
"The researchers took a growing trend and provided a good, thorough, scientific validation," Camp said. "This kind of thoughtful approach can improve the quality of the donor lungs we have, which in the end can mean more donor lungs for recipients."
Typically, about 15 to 20 percent of lungs from people who are
brain dead are viable for transplantation, according to the study.
Camp said that kidneys and livers are relatively easy to keep
viable for transplant, but hearts and lungs are more difficult.
Using the protocols at U.S. hospitals has the potential to
virtually eliminate the lung shortage, Roberts said.
"If you can double the amount of lungs available for transplants, that can almost wipe out the shortage between what is demanded and what is available," Roberts said. "It would make a huge difference."
The U.S. National Heart, Lung, and Blood Institute has more on
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