Our unit is looking at the use of lowering dialysate temperature to @35 degrees C to see if it helps prevent dialysis hypotension in susceptible patients. I have heard it is very useful but the patients get cold. Anybody do this and any comments

Keep in mind that what you're trying to do is to prevent vasodilation, not force vasoconstriction.

When I started in dialysis, I asked another nurse why they used cold dialysate on some patients. He said, "You know, when you're cold, you vasoconstrict to stay warm. We keep their blood pressures up this way." It sounded good to me at the time.

However, I later heard a completely different rationale for cold dialysate at a meeting. It was explained that when a patient starts their dialysis treatment and ultrafiltration is applied, the patient's BP drops, and the body compensates for this by vasoconstricting. One of the effects of vasoconstriction is an increase in body temperature. So, throughout the dialysis treatment, the patients are in a constant state of vasoconstriction and they accumulate a lot of heat that they would normally dissipate. (This is why a lot of patient's ask for fans an hour or two into the treatment.)

Then, their body temperature rises until the temperature regulating center in the hypothalamus finally overrides the body's BP regulation. The patients vasodilate to get rid of this excess heat and their BP crashes.

So, cold dialysate should remove excess heat, not force a vasoconstrictive response. If my patient's are getting cold, I'm taking too much heat off them.

If you take a patient temperature before dialysis, the temp is usually less than 37C. Most dialysis machines are set to 37C. When you set to 37C, you heat up the patient to 37C over the treatment. If you find their pre-treatment temp is 36.5, set the machine to 36.5 and the final patient temp will be around 36.5. As general rule, set the machine to a patient's pre-dialysis temp and the final result is usually around the pre-temp.

The 37C temperature is a carryover form the old positive pressure days with low flow rates and canister/coil use. The temp was used to compensate for the heat loss. Nowadays, with higher flow rates and a controlled heat exchanger (the dialyzer), very little heat is lost as it travels from the dialyzer to the patient

Thank you both for your replies. I shall consider them both when we trial this.

Our unit has been using lower dialysis temp.
for over a year on selected pts. We have had
fewer hypotensive episodes with its use. If
we forget to lower the temp. on the machine I
have noticed a difference on some pts. On most of these we also sod. model. Our critera is by past experience as to ind. response to the treatment. Our machines a Althine which only allow a 35.5 temp. The 35 sends them into an alarm mod because the temp. will drop below the 35 mark. Hope this helps. Good Luck

A literature search will find articles on lower dialysate temps to control BP. In some patinets a slight drop of 0.5 C will help to maintain the BP. You can drop the temp 0.5 with each machine/BP check q 30 minutes as the patient tolerates the decrease. This can be used with other supportive measures such as Sodium +/or UF modeling or med support. Works well with some patients and is worth a trial use for individual patients. It is very important we get better at prevent hypotension as noted in the DOQI HD Adequacy Guideline # 15. Great to see interest in preventing and controlled tx related hypotension!