Science Interviews

Interview

Tue, 20th Sep 2016

The do's and don'ts of organ donation

Alsion Galloway-Turner & Professor Chris Watson, Addenbrooke's Hospital

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As national organ donation week drew to a close last Sunday, Graihagh Jackson Organ donation formmet with Alison Galloway-Turner, specialist organ donation nurse at Addenbrookeís hospital to find out why we have such a shortage of donorsÖ

Alison - Half a million people die in the UK every year but only one per cent of them die in a way thatís suitable for them to become organ donors.

Graihagh - When you say suitable - what do you mean?

Alison - Well to donate your organs you would need to die in an intensive care unit on a ventilator having had either brain stem tests where a patient has sustained a serious head injury and they have no brain function and no brain activity, or there is a plan to withdraw treatment because treatment is futile and itís expected that you would die quite rapidly after treatment is withdrawn.

Graihagh - Does that explain why the waiting list is so long in part?

Alison - The waiting list remains very long because more people are now put on the waiting list, patients are now surviving longer. Certainly we have improved our donor numbers - itís gone up by 50 per cent in the last five years but we still have not improved our consent rates - so still forty per cent of families saying no to donation.

Graihagh - Why is that?

Alison - Itís for a number of reasons. In cases where families know what their relative wanted ninety per cent of them say yes but in cases where families donít know, fifty per cent of them say yes which just shows if you havenít had that conversation and made your wishes known, families feel reluctant to consent on your behalf.

Graihagh - Can you tell me what would happen in an ideal situation then, from start to finish, and where you would hand over to a surgeon?

Alison - When we are notified we would look at the organ donor register to see if that person had expressed a wish. Along with intensive care or A&E staff we would approach the family to sensitively discuss organ donation with them. If they give consent for organ donation, we process that organ donor.  So we would gather as much information as we could about their medical history, their current medical condition to be able to hand that over to recipient centres so organs can be allocated, recipients can be found for those organs.

Graihagh - However, even at this stage, some of these organs arenít fit for transplantÖ

Chris - There are lots of reasons why an organ may not be suitable. There may be concerns about the way the donor died, a disease the donor had.  So, for example, if they had a cancer thereís a potential that might be transmitted - things like that.

Graihagh - Thatís Chris Watson. Professor of Transplantation here in Cambridge.

Chris - One area that has been a problem ever since transplantation started is the damage an organ undergoes in that period when you remove it from the donor to reimplanting it in the recipient, that ischemic time, that time when thereís no oxygenated blood going to the organ. And historically, in the donor, when the circulation stops we flushed it with a cold solution to optimise the storage of the organ but that doesnít do a perfect job and so the organ always suffers during that storage period and then, when we come to transplant it, it may or may not work straight away.  For kidneys, if they donít work straight away that'sí fine -  we can support the patient with dialysis until it kicks into action.

If a liver doesnít work straight away, itís a different kettle of fish. You canít live without a  functioning liver and we canít support the liver in any sensible way for any length of time so you need an urgent re-transplant. Typically, patients listed for an urgent re-transplant wouldnít expect to live more than two or three days so you would have to have a compatible liver, in a suitable size and quality within a very narrow time period to rescue someone if youíve given them a liver thatís not tolerated that preservation time for whatever reason.

So we look to try and improve the preservation of a liver at the moment by putting it on a machine to see if we can arrest the cold ischemic time, arrest that period of cold storage, but at the same time test the liver to see if itís going to work when we transplant it. And thatís the challenge. We want to be able to say at the end of a period on the machine, this liverís going to work well and we can transplant it safely into a recipient.

Graihagh - How are you going about doing that?

Chris - So the liver comes out of patient, itís cooled down in a typical way, itís brought to Addenbrookeís and then we will prepare it for transplantation but the patientís not ready yet and we havenít decided to use it yet. We'll then connect the liver up to a machine by putting pipes in the artery and the portal vein, which is the two ways blood gets to the liver, and then collect the blood that drains out of the liver, recirculate it through a device that oxygenates the blood and pumps it round at different rates into the artery and vein, and then we can measure at intervals whatís going on.

So, for example, youíll know from running that youíre not breathing as much oxygen in as you need so lactic acid accumulates, so you start getting cramps. With the liver being ischemic lactic acid accumulates and by putting oxygen through it we can see how quickly the liver metabolises that lactate and gets rid of it and thatís a marker of the liver working.

Graihagh - And this is entirely novel - no-oneís being doing this before?

Chris - The first cases doing this were the end of 2014 and, I would guess, thereís probably been about two hundred patients have had livers preserved this way; some of them here and some of the elsewhere in the UK.

Graihagh - That sounds pretty  impressive - two hundred livers saved and, I guess, two hundred lives saved as a result?

Chris - Yes it did. When it works well itís really good.

Graihagh - I think youíre being modest!

Chris - On the background of this we have a programme of research using livers that have been declined by all the centres and then we do lots of other experiments with the liver. And, actually, four of the livers that we have that have been declined by all the other centres, when we put it on the machine itís been immediately clear that the liverís actually very good and should be transplanted and weíve gone on to transplant them. So, yeah, we have used livers that actually were just consigned for research and not transplantation. So that is very gratifying when we can do that.

Graihagh - So it really is a case of every little helps in this instance?

Chris - Yes, the one thing a patient would really regret is never getting the call. And one of the patients actually said this to me that his greatest fear was not actually been called in for a transplant. It wasnít that it would go wrong or anything, it was actually never having the opportunity.

For liver transplantation around about ten percent, so one in ten patients, will die while theyíre waiting and another seven or eight percent will be removed from the waiting list because theyíre unfit or for some other reason that theyíre no longer appropriate to have a transplant.

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