What are the implications of long ischemic times during renal transplantation?

What are the implications of long ischemic times during renal transplantation?

Cardiac arrest can occur after renal artery and vein anastomoses. It usually happens subsequent to releasing the vascular clamp and is most likely due to acute hyper-kalemia. K⁺-containing solutions used to preserve the kidney during cold ischemic time may be washed out to the general circulation. If the external iliac artery was clamped, additional K⁺ can be released into the circulation after unclamping from an ischemic limb. The result is hypoten-sion and metabolic acidosis from an acute washout of vasodilating substances. Although cold ischemic time can extend up to 48 hours, 30 hours is a better predictor of successful transplantation.

Warm ischemic time refers to the time from cold ischemic time to the revascularization of the kidney in vivo. This includes the renal artery and vein anastomoses but not that of the ureter. It is important to limit warm ischemic time to less than 45 minutes. Longer warm ischemic times are associated with poorer outcomes. Blood pressure con-trol is also imperative. Cardiac output must be maintained to provide adequate perfusion of the newly transplanted kidney. The use of vasoconstrictors is discouraged during kidney transplantation; however, it is sometimes necessary to maintain adequate blood pressures.