To cool, or too cool: Is reducing dialysate temperature the optimal approach to preventing intradialytic hypotension?

Abnormal decreases in blood pressure during hemodialysis are frequent in end stage renal disease (ESRD) patients treated with hemodialysis, and thought to be largely due to an inadequate cardiovascular response to the rapid blood volume decline. Intradialytic hypotension (IDH) and cardiac instability during dialysis can increase risks for negative health consequences and is possibly preventable though several types of interventions. One intervention that holds promise for prevention of IDH in hemodialysis patients is to reduce the temperature of the dialysate to or below the patient's core temperature. A considerable number of randomized studies have demonstrated a short term benefit of using a cooler dialysate temperature for the prevention of IDH and improved cardiac stability. Despite this, a key observational study was not able to show long term improvements with lower dialysate temperatures utilized in routine clinical practice, albeit possibly confounded by indication. It appears that cooling the dialysate may be reasonable to consider on an individual basis for patients who suffer from persistent IDH if they can tolerate the adjustment and it is effective. However, careful assessment of the etiology of IDH should be performed when considering treatment options. In this review, we detail the current body of evidence on the effectiveness of using low dialysate temperatures for prevention of IDH in ESRD patients, and suggest areas where further research is needed.