Renal perfusion significantly declined during standard HD but not during cooled HD. Percent of baseline per kidney perfusion before, 3 hours into, and after dialysis, where results are given as average±SEM. (A) In 29 standard HD patients (57 kidneys), the drop in renal perfusion during HD was statistically significant compared with pre- and post-HD blood flow values (P<0.005). (B) In 15 standard and cooled HD patients (30 kidneys each), there was a smaller decline in renal perfusion during cooled HD (not statistically significant) compared with standard HD.