Donor Selection and Procedure
Since the intestine is very sensitive to ischemia, hemodynamically stable donors are preferred. Consequently, potential donors who are managed on high doses of vasopressors, those with extended periods of hypotension, or those with cardiac arrest or cardiopulmonary resuscitation are excluded. Patients with malignancies or systemic sepsis are also avoided. The donor and recipient are ABO identical, although human leukocyte antigen matching is random. Ideally, donors with a positive lymphocytotoxic cross-match should be avoided; however, there is usually a prolonged wait for cross-match results, which could endanger the graft by extending the cold ischemia time.
CMV-seropositive donors should not be considered for CMV-seronegative recipients because of the significantly higher mortality rate in this group. This guideline should be strictly adhered to in isolated intestine transplantation and whenever possible in the other types of grafts.
Weight is also an important consideration in donor selection. Preferably the donor should be similar in size or smaller than the recipient since the volume of the abdominal cavity is often reduced due to previous surgeries. In pediatric patients, the weight range of an acceptable donor may range from 50% less to 20% greater than the recipient weight. Larger donor organs may be implanted since children with end-stage liver disease often have abdominal distention. It is also possible to decrease the length of donor bowel in patients receiving an isolation small bowel and decrease the size of the liver graft in those requiring the larger composite graft.[54,55]
Intestinal decontamination is done in all donors with amphotericin B, an aminoglycoside, polymixin, and broad-spectrum antibiotics before and during procurement. Historically, donor lymphoid tissue was treated with antilymphocyte globulin, OKT3, or irradiation at some centers, but this is not common practice today.
The donor operation has been described previously.[51,54,57] Procurement takes approximately 3 hours and involves isolation of the stomach with division at the pylorus and transection of the ileum at the ileocecal valve with mobilization of the colon. In situ perfusion with University of Wisconsin preservation solution is performed with venous bed decompression. The isolated small bowel is separated from the composite graft as a back table procedure and then stored in ice for transport. Mean cold ischemia time, the time between organ procurement and implantation, is approximately 8 hours (range of 2.8 to 14.8 hours) with no significant evidence of preservation injury.[17,59] A cold ischemia time of less than 10 hours is recommended to avoid preservation injury.
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