Chapter 2544: Duration Control Is Crucial

Zhongshan Medical First Affiliated Hospital definitely has the technical capability for this, so there is no need for them to fly over. In a while, the surgeon responsible for harvesting the donor heart during the operation will be Doctor Ye Chuanguang.

"Do the doctors on your side have any specific requirements for us?" Ye Chuanguang asked.

While Xie Wanying was talking on the phone, she pulled the ballpoint pen out of her pocket.

Seeing this, Student Wei helped her take out a notebook so she could write in it.

Xie Wanying wrote down the items she needed to coordinate with the other side and handed them to Teacher Cheng to review.

Doctor Cheng Yuchen read as he nodded.

After obtaining her teacher’s approval, Xie Wanying said, "First, the transport distance for the donor heart is relatively long, so the time on the road will be prolonged. There are some preparatory measures that will require cooperation and extra effort from you and your team, Teacher Ye."

"No need to be so polite," Ye Chuanguang said candidly. "Even if you hadn’t called, we were already planning to ask what your strategy was. Do you need us to infuse the donor heart again with Cardiac Arrest Solution from the aortic root for preservation?"

"Yes." An excellent senior: no need for many words, he understood almost instantly.

"But you must be clear that the cold ischemia time for the heart is best kept under five to six hours," Ye Chuanguang nagged in a cautionary tone, reminding them not to think that adding a few extra preparation steps would make everything foolproof—it can at most stretch the time a little.

Cold ischemia can be regarded as a technical term specific to organ transplantation. Before talking about cold ischemia, we first mention another similar technical term: warm ischemia.

The time interval from when the donor’s heart stops beating to when the organ is removed and placed under cold preservation is called warm ischemia. Correspondingly, cold ischemia refers to the period from when the organ leaves the donor to when it is implanted into the recipient, and here it primarily refers to the time spent in transport.

Every type of organ has upper limits for both warm and cold ischemia times. For example, the heart has the shortest upper limits: ten minutes and eight hours, respectively. These ten minutes and eight hours are extreme upper limits, essentially a high?risk gamble. No one can afford to take such risks lightly. Hence Doctor Ye’s statement that cold ischemia is best not extended beyond five to six hours. At their hospital, the warm ischemia time during donor heart procurement will be controlled within five minutes.

What does it mean to infuse Cardiac Arrest Solution? To explain further: when the organ is removed from the donor, the cells are not dead yet and continue to carry out metabolism. Because blood flow is interrupted and there is no blood supply, the explanted organ inevitably undergoes self?consuming metabolic damage. It is easy to imagine that the warm ischemia interval causes the greatest injury to the donor organ, and that this step must be performed by highly skilled specialist surgeons to shorten the operative time as much as possible.

How then should we protect the donor heart during the cold ischemia phase? From the standpoint of medical technology, the ideal is to use mechanical devices to simulate normal human physiology and continuously perfuse the donor heart, thus minimizing damage. The problem is that long?distance transport makes this essentially unfeasible, and so we have to settle for second?best approaches: using other methods to slow the metabolic rate of the donor heart and reduce injury. Therefore, standard organ preservation solutions necessarily incorporate hypothermia and other components to suppress cellular metabolism in the organ.

The heart’s energy consumption arises mainly from the mechanical activity of contraction and relaxation, and from myocardial cell metabolism. The former accounts for about ninety percent of total consumption. Using Cardiac Arrest Solution can stop the mechanical activity of the heart, and combined with hypothermia to reduce myocardial metabolic rate, the two together are like one plus one, producing a multiplied effect in reducing energy loss.

Protecting the myocardium is one aspect.

On the other hand, unlike the liver, the heart has a special structure; multiple anastomotic sites are required between the donor heart and the recipient.