Two RCTs1014,1015 showed no effect of CPB temperature on renal function in patients under- going CABG, whereas a 2010 observational study1016 of 1072 subjects identified a relationship between a CPB temperature 27 C and the development of AKI (OR: 1.66; 95% CI: 1.16 to 2.39; P 0.005). Although off-pump CABG may theoretically avoid CPB-related renal injury, the cardiac manipulation that is often required to obtain adequate exposure may cause transient decreases in cardiac output, increased peripheral vasoconstric- tion, and decreased renal perfusion.1017 A meta-analysis of 6 RCTs and 16 observational studies (encompassing data from 27 806 patients) suggested a modest beneficial effect of off- pump CABG in reducing the incidence of AKI but no advantage in reducing the incidence of AKI dialysis.977 These findings were confirmed by another published RCT of 2203 patients, in which the incidence of AKI dialysis was similar among those undergoing off-pump and on-pump CABG (0.8% for off pump; 0.9% for on pump; P 0.82).61 Considering the low (approxi- mately 1%) incidence of AKI dialysis in subjects undergoing CABG, available RCTs are underpowered to detect a difference in outcome. In patients with renal dysfunction preoperatively, it might be reasonable to perform off-pump CABG to reduce the risk of AKI.974 976,978,996 During CPB, hemodilution is induced to reduce blood viscosity and plasma oncotic pressure to improve regional blood flow in the setting of hypothermia and hypoperfusion. However, an excessively low hematocrit on CPB is associated with increased adverse events and in-hospital deaths.1018 In patients undergoing isolated CABG, it has been reported that the mortality rate of patients with a single hemat- ocrit value 19% was twice that of those with a hematocrit of 25%.1019 On the basis of these data, a hematocrit 19% on CPB should be avoided. 