lunes, 4 de marzo de 2019

How is a kidney transplant performed?

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

A kidney transplant is needed in persons who have end stage renal disease with 90% of their kidneys not functioning adequately to remove the waste products from the body.

The patients are put on a waiting list for a donor kidney. As soon as a suitable donor kidney is found, the transplant centre will contact the patient who is maintained on dialysis till the kidney is available.

Those who have the availability of a living donor from a family member or close relative need not wait on the list.

Two main types of kidney transplant

Kidney transplant is of two main types – living donation and deceased donation.

Living donation

There are two kidneys in the body and a person only needs one kidney to survive. Thus, unlike other organ donations like heart and liver, living donors may donate a kidney. This ideally should be a close relative so that the blood group and tissue types match. Tissue types are determined by a test called HLA matching. This type of donation is known as a living donation.

A similar blood and tissue type ensures that there is less risk of the body rejecting the kidney. HLA stands for human leukocyte antigen and is a genetic marker located on the surface of the white blood cells. All persons inherit a set of three antigens from their mother and three from their father. A higher number of matching antigens increases the chance that the newly donated kidney will last for a long time.

Deceased donation or Cadaveric donation

Kidney donations are also possible from donors who have recently died. These may not match the recipient in tissue and blood group type and face the risk of being rejected by the body. The body perceives the new kidney as foreign object and mounts an immune attack against it. This can be suppressed by using long term immunity suppressing drugs.

When contacted the patient is checked again for new medical problems and is advised not to eat or drink anything to prepare for a surgery as early as possible. For kidney transplant surgery anesthesia at least 6 to 8 hours of complete fasting is required. Patient is asked to take all report and prescriptions along with their bag of necessities for hospital stay.

Before surgery a medical team examines the donor kidney if the kidney was taken from a recently deceased donor. If the kidney is in good condition and suitable, the operation needs to be performed immediately, to ensure chances of success.

The patient is wheeled into the operation theatre and a general anesthetic is given to render him or her unconscious.

Kidney transplant surgery

The most widely used operative technique is the Gibson incision. First a cut is made over the lower abdomen through which the donated kidney is put into place. Unless there is an indication like an infection or cancer the recipient’s own kidney is left in its position.

As a next step the blood vessels from the lower abdomen are attached to the donated kidney much like the original kidney. This ensures that the donated kidney has the blood supply that it needs to function properly. Finally the ureters that take the urine from the kidneys into the urinary bladder for stage are attached to the donated kidney.

This surgery is a complex one and may take around three to four hours to complete. After the procedure the skin is tied up with sutures or stables leaving a tube behind to drain blood and fluids collecting in the operative area. Patient is wheeled back to a recovering room.

Pain medications are provided for pain relief. Antibiotics are given intravenously for prevention of infections. Immunity suppressing medications including ciclosporin, azathioprine, mycophenolate mofetil, tacrolimus, sirolimus or prednisolone are begun as soon as possible to prevent the body rejecting the new donated kidney.

Most patients can leave the hospital in five to seven days. In around 7 out of 10 people who have a kidney transplant, their new kidney begins working immediately after surgery. In some it may take around 4 to 6 weeks to function normally. If this is the case, the patient requires dialysis during this time. Patients need to be followed up for life.