Sodium modeling, hypotension, and weight gain in HD

Abstract

Sodium modeling is a strategy to decrease the incidence of hypotension during hemodialysis. Side effects include increased interdialytic weight gain. By default, all patients at our dialysis center are started on HD with sodium modeling. Purpose: To compare weight gain and blood pressure after discontinuation of sodium modeling. Methods: Ten patients using sodium modeling were changed to a standard sodium bath after a change in attending physician. After IRB approval, we collected and retrospectively reviewed the change in interdialytic weight gains, episodes of hypotension (defined as an episode of hypotension requiring staff intervention), and starting and ending blood pressure. Data from one week prior to Na change (PRE) was compared to one week after Na change (POST) using a paired samples t‐test. Results: Data from 4 men and 6 women with a mean age of 65.2 ± 13.7 years was reviewed. ESRD diagnoses included diabetes (n = 4) and hypertension (n = 6). Interdialytic weight gain significantly decreased after discontinuation of sodium modeling (PRE 3.86 kg, POST 3.11 kg, p = 0.004). No significant change in blood pressure at the start (PRE 154/82 POST 156/83, p = 0.745) or end of HD (PRE 123/69, POST 130/67, p = 0.201) was observed. However, the frequency of symptomatic hypotension increased after change to standard sodium bath (PRE = 6%, POST = 27%, p = 0.031). All episodes of hypotension occurred in 3 of the 10 study patients. No patient required cessation of HD or transfer to the emergency department. The degree of weight gain was not correlated with the likelihood of intradialytic hypotension. Conclusion: A change from sodium modeling to standard sodium dialysate lowers interdialytic weight gain but increases the incidence of mild symptomatic hypotension. Further study is needed to determine whether mild hypotension is preferable to increased interdialytic weight gain and to determine the relationship of increased weight gain to complications of volume overload such as LVH and CHF.