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HEARTS can now be kept beating outside the body for nearly two days. The
portable device that keeps them alive promises to buy precious time for
transporting organs and preparing for transplant operations.

At the moment, donated organs are kept in an icebox while they are being
transported. A heart only survives for four to six hours in these conditions,
while kidneys and livers last for up to 12 hours. But Waleed Hassanein and his
colleagues at TransMedics of Woburn, Massachusetts, have now kept animal hearts
working for up to 36 hours, and kidneys and livers for up to 48 hours.

Their machine, called the Portable Organ Preservation System, or POPS, keeps
organs at normal body temperatures and pumps blood through them continuously. A
drip feeds a mixture of nutrients and electrolytes into the blood. Under these
conditions, hearts keep pumping at about 60 to 80 beats a minute without any
external stimulation.

“The POPS system maintains organs in their normal functioning state—the
heart continues to beat, the kidney makes urine and the liver makes bile,” says
Hassanein. The machine collects and removes these products, which can help
surgeons evaluate an organ’s condition, he says.

Preliminary experiments suggest that the device also works for pancreases and
lungs, he says. The team has carried out nearly 500 experiments on animal
organs, and is planning tests with human organs.

The device could be useful, says Robert Higgins, a director of the United
Network for Organ Sharing, based in Virginia, which coordinates organ
transplants in the US. “It might also alleviate the pressure on transplant teams
to procure organs and expedite them to the site of the recipient, often in the
middle of the night.”

Surgeons could even resuscitate organs from donors whose hearts have stopped
beating. “This gives you the luxury of procuring or harvesting organs that we
normally turn down today,” Hassanein says. Because of the shortage of healthy
donor organs, doctors are increasingly giving people “repaired” organs.