VANCOUVER, B.C.—An overhydration (OH) index derived from spectroscopic bioimpedance may help guide ultrafiltration in hemodialysis (HD) patients and the modification of their antihypertensive therapy, according to a researcher.
This and other measures could help prevent volume overload and reduce cardiovascular risk, said Ricardo Correa-Rotter, MD, head of the Department of Nephrology and Mineral Metabolism at the National Institute for Medical Science and Nutrition in Salvador Zubiran, Mexico.
Dr. Correa-Rotter and his team are exploring the clinical benefits of bioimpedance spectroscopy in HD patients. Results from a study they published last year indicated vector bioelectric impedance analysis can be used at the bedside to accurately assess volume and nutrition status in patients on chronic HD (Clin Nephrol. 2010;73:300-308).
In a study Dr. Correa-Rotter, presented here at the World Congress of Nephrology, he and his co-investigators used this novel approach to follow 29 chronic, anuric HD patients. Six patients were normotensive and not taking any antihypertensive drugs and 23 were hypertensive. As the investigators expected, the hypertensive patients had a significantly higher volume status or OH index score—as derived from bioimpedance spectroscopy— than normotensive subjects. This condition was present predialysis and continued after repeated dialysis sessions in patients without clinical signs of edema or volume overload.
“We always claim to keep our patients as dry as possible, but we’re probably not doing so or could be doing a better job” Dr. Correa-Rotter said.
Bioimpedance spectroscopy also showed indirectly that hypertensive patients had a much higher sodium body pool.
“What we will certainly see in the future is improved hemodialysis equipment that can give us better information on how we’re doing with ultrafiltration,” he observed. “The spectroscopic technology may be a very good technique for doing this. It is in use now as independent equipment and it could soon be used as part of hemodialysis machines.”