Cells within the kidney become ischemic with decreased or absent blood perfusion while remaining at physiologic temperatures. There are two periods of time when this occurs: during organ recovery and during implantation. During organ recovery, warm ischemia begins when the vessels are cross clamped or when there is inadequate perfusion resulting from the donor’s failing status, and continues until it is perfused with a cold preservation solution (see also cold ischemia time). During implantation, the time begins when the kidney is removed from ice until blood perfusion is reestablished.
Halazun, K.J., Al-Mukhtar, A., Aldouri, A., Willis, S., & Ahmad, N. (2007). Warm ischemia in transplantation: Search for a consensus definition. Transplant Proc, 39 (5), 1329-31. Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/17580133