Static cold storage

Static cold storage

Hypothermia suppresses metabolism to maintain organ viability . The first requirement is to flush the donor organs with an appropriate preservation solution at a temperature of approximately 4°C ( Figure 88.3 ). This is normally done in situ via cannulae placed in the donor aorta and portal vein. This process has three e ff ects: (i) it flushes blood out of the microcirculation to prevent thrombosis; (ii) it cools the organs to a temperature of <5°C and so reduces tissue oxygen requirements; (iii) it replaces the normal extracellular fluid with the preservation fluid. Sir Hans Adolf Krebs , 1900–1981, Professor of Biochemistry , University of Oxford, Oxford, UK. electrolytes, an impermeant and a bu ff er. In general, the + ion concentration electrolyte composition mimics the high K + and low Na ion concentration of intracellular fluid. This eliminates ionic fluxes, and therefore the movement of H O 2 across cell membranes. Impermeants such as mannitol, lacto - bionate and ra ffi nose are large osmotically active molecules. They cannot pass through the cell membrane and remain in the extracellular space. Here, the y prevent cellular swelling by counteracting the osmotic force from intracellular proteins. The bu ff er component of preservation fluids is based on either – 3– HCO or PO and acts to maintain a stable physiological pH 3 4 in the extracellular space. A number of di ff erent preservation solutions are available, but the University of Wisconsin (UW) solution is widely regarded as the current gold standard.

Figure 88.3 After removal from the donor, the kidney is /f_l ushed with chilled organ preservation solution and, if necessary, stored brie /f_l y on ice until transplanted into the recipient.