Potential Role for Using Bioimpedance to Reduce the Risk of Intra-Dialytic Hypotension

Intra-dialytic hypotension is the most common complication of hemodialysis treatments. Traditionally, clinical judgment determines the post-dialysis target weight and ultrafiltration volumes. We examined the role of pre-dialysis bioimpedance measurements and subsequent intradialytic hypotension.

Segmental bioimpedance measurements were taken pre-dialysis from hemodialysis outpatients who had been acutely admitted to the hospital, with dialysis prescriptions and ultrafiltration targets determined by the clinical team.

We studied 42 patients with a mean age of 66.9 ± 12.5 years. Among 28 patients (66.7%) that developed intradialytic hypotension, the group had shorter stature (163.9 ± 8.8 vs. 170.1 ± 7.8 cm, p < 0.05), and lower N-terminal brain natriuretic peptide levels (11 269 (3523-33 843) vs. 28 454 (4957-59 867) pg/mL, p < 0.05). The extracellular water to intracellular water ratio for the whole body was lower in the intradialytic hypotension group (68.0 ± 3.9 vs. 70.5 ± 3.4, p < 0.05), and the relative extracellular to intracellular ratios were lower when the trunk, right leg, and left leg were compared to the left arm (p < 0.01). Multivariable analysis showed that intradialytic hypotension was associated with the extracellular to intracellular ratio of the trunk compared to the ratio in the left arm (odds ratio 0.80, p = 0.01) and height (odds ratio 0.88 p = 0.03).

We found that hemodialysis patients acutely admitted to hospital with a relatively lower extracellular to intracellular ratio of trunk compared to a similar ratio in the left arm had a greater incidence of intradialytic hypotension. As such, reviewing segmental bioimpedance may aid clinical assessments of patients in setting ultrafiltration volumes and post-dialysis target weights and prevent intradialytic hypotension.