How Organ Transplants Work

The Surgery

When a donor's family authorizes the removal of organs, several surgical teams immediately begin work recovering the organ. (While the term harvesting is still in use, many organizations now prefer the term recovery because it is more sensitive to the donor family.) To understand what is involved in this procedure, let's focus on a particularly harrowing operation: the heart transplant.

­The first step for all the harvesting teams is to cut open the donor's chest. Next, a surgeon saws through the breast bone and pulls the ribs outward to reveal the heart. While other teams are working on other parts of the body, the heart team clamps the different blood vessels leading into the heart and pumps in a cold, protective chemical solution. This solution stops the heart from beating and helps preserve it during transportation.

The surgeons then sever the vessels and remove the heart from the body, placing it in a bag filled with a preservative chemical. This bag is then packed in an ordinary cooler filled with ice, which is rushed to the recipient's hospital, often via plane or helicopter.

Meanwhile, the recipient is fully anesthetized and his or her chest is shaved. He or she is wheeled into the surgery room and covered in sterile cloths, leaving only the chest exposed. Typically, the surgery won't actually begin until the heart arrives, just in case there is some problem in transport.

When the donated heart has arrived, the transplant team begins the procedure. First, they hook up an IV and inject an anticoagulant into the patient's bloodstream. This keeps the blood from clotting during the transplant procedure.

As with the recovery surgery, the team begins the surgery by making an incision in the patient's chest, sawing through the breastbone and pulling back the ribs. The doctors then hook up a heart-lung machine to the patient's body. The heart-lung machine's job, as you might expect, is to act as the patient's heart and lungs temporarily. The machine's plastic tubes are connected to blood vessels leading to and from the heart. Instead of being pumped to the lungs to get rid of carbon dioxide and pick up oxygen, blood returning to the heart is diverted to the machine. The machine drives the blood through a series of chambers to release carbon dioxide and pick up oxygen and then returns it into the body to be re-circulated. This enables the surgical team to remove the heart without disrupting respiration and circulation.

Additionally, the heart-lung machine can be adjusted to warm or cool the blood. During the operation, it is set to cool all the blood that passes through it. This cools the rest the body, which helps protect the other organs during the operation. Typically, the machine will have an attachment to suck up blood from the surgery area and send it directly back into the bloodstream.

When the blood has been effectively diverted around the heart and lungs, the surgeons remove the diseased heart by cutting it loose from the attached blood vessels. The back walls of the atria, the upper chambers of the heart, are actually left in place. The surgeons remove the back walls of the donor heart's atria and suture the donor heart to the remaining tissue of the old heart. Then they suture the blood vessels formerly leading to the diseased heart to the vessels leading out of the donor heart.

After the new heart is in place, the team gradually warms up the blood flowing through the patient's body. As the body warms a little, the heart may start beating on its own. If it does not, the team applies an electrical shock to get it going. The team lets the new heart and the heart-lung machine share the job of circulating blood for some time, giving the heart time to build strength.

If everything is working correctly, the team wires the halves of the breast bone back together and stitches up the patient's chest using dissolving stitches. The patient is hooked up to a ventilator and brought to the recovery room. In a few hours, most patients regain consciousness. They may be ready to leave the hospital within a week.

Typically, the entire procedure only takes about five hours. But patients have to work the rest of their lives to make sure the donated organ continues to function. In the next section, we'll find out what is involved in this post-transplant treatment.