On yesterday’s episode of Grey’s Anatomy, a young patient who needed a lung transplant was also a lousy candidate for one, since he had too many risks. Instead of foregoing the whole thing, an ex-vivo lung transplant was performed on him instead.

Why does someone need a lung transplant, anyway?

There are some diseases that cause such damage to the lungs that a new lung is necessary. Such diseases include (don’t fret the confusing names – we will cover them at one time or another here on A Disease A Day) chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, cystic fibrosis, idiopathic pulmonary hypertension and others.

So why not give everyone the lungs they need?

There aren’t that many lungs that can be donated to begin with – only about 15-20% of donor lungs are acceptable for transplantation, since lungs are more susceptible to injuries than other donated organs (such as the heart).

Even when we have found a suitable lung for transplantation, not everyone waiting for a lung will get one. Each person waiting for a lung transplant has a score, based on the lung allocation score. For example, people who have a more immediate need for the lung come before those who can wait. Other factors, such as the illness the patient has, other diseases they have, etc. determine their score.

This means that many patients, like the one on the Grey’s Anatomy episode, are left far behind in the list, with a very low chance of ever getting a lung before dying.

What’s an ex-vivo transplant and how does it help things?

This technique was invented in 2008 by a team of lung transplant surgeons led by Dr. Shaf Keshavjee at Toronto General Hospital.

What it does is perfuse a special solution into an injured lung. It lets doctors “treat” the injured lungs while they are outside the body to make them suitable for transplantation. The technique can double the number of lungs fitting for donation.

How is it done?

After the donor lungs are removed from a deceased donor, they are transferred to a protective, transparent bubble-like chamber (like the one seen on the show). Then a series of steps is taken, in which the lungs are connected to a circuit composed of a pump, ventilator and filters through which oxygen, nutrients and a special solution are injected to the lung.

The bubble-like chamber with the lungs in it. Image courtesy of University Health Network

And on a final note – why is it called an ex-vivo transplantation?

Ex-vivo in Latin means “out of the living”. In this case, the healing process for the lungs occurs outside of a human body, inside this bubble-like chamber.

Here’s a video showing the repaired lung in action -

What next?

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