Techniques: Cooler Dialysis Fluids May Help With Insomnia and Fatigue

April 3, 2007
Vital Signs

Techniques: Cooler Dialysis Fluids May Help With Insomnia and Fatigue

By ERIC NAGOURNEY
The New York Times

For all the lives it has saved, kidney dialysis has drawbacks, among them insomnia. As many as 8 of 10 patients tell their doctors they have trouble sleeping and suffer from fatigue during the day.

A new study (see below) suggests there may be a simple remedy. Writing in the current Journal of Sleep Research, scientists say the problem seems to be that dialysis treatment raises body temperature.

So why not lower the temperature of the dialysis fluids that help filter the blood of people with kidney failure?

“It is quite possible that significant improvement of sleep in a group of patients plagued with these problems may be as simple as adjusting the dialysate temperature setting on the machine,” wrote the researchers, who were led by Kathy P. Parker of Emory University.

By convention, the temperature of the fluids is set at about body temperature. The researchers tried setting it about three degrees cooler. When the volunteers were given dialysis at lower temperatures, they fell asleep an hour earlier, on average, and slept an hour more.

The study was preliminary, involving only seven patients. But a bigger study is under way, and if the results are confirmed, the findings could affect a lot of people.

About half a million Americans are on dialysis, the researchers said, a figure that is expected to grow substantially in coming years.

URL: http://www.nytimes.com/2007/04/03/health/03tech.html?_r=1&adxnnl=1&adxnnlx=1175904459-H8WaewsmcHXenwnEso2C9Q&oref=slogin

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STUDY: go to http://www.blackwell-synergy.com/doi/full/10.1111/j.1365-2869.2007.00568.x?cookieSet=1 to read complete study

Summary: Hemodialysis (HD) induces physiological changes that may affect the ability to dissipate heat and adversely affect sleep. We studied the effects of altering dialysate temperature on polysomnographic measures of nocturnal sleep and the time course of proximal skin temperature. The sample included seven stable HD patients. The three-phase randomized trial was conducted in a research facility. After one acclimatization night, subjects were readmitted in the evening on two additional occasions for 42 h and received HD the next morning in the warm condition (dialysate 37 °C) and cool condition (dialysate 35 °C) in random order. Continuous proximal skin temperature (axillary, Tax) and polysomnographic measures of sleep were recorded the nights before and after HD was administered. Highly significant findings included that the time course of Tax was markedly affected by dialysis temperature. There was a greater drop of Tax in the early morning following the warm condition than during the baseline nights or in the cool condition. Logistic regression indicated that the odds for the occurrence of sleep and its deeper stages were strongly and positively associated with Tax. Time of sleep onset was earlier in the cool condition (P = 0.03) with trends toward longer total sleep times (P = 0.09) and shorter rapid-eye-movement latencies (P = 0.09). These observations suggest that the use of cool dialysate during HD may improve nocturnal sleep by decreasing sympathetic activation and sustaining the normally elevated nocturnal skin temperature until later into the morning hours.