Low-Intensity Intradialytic Exercise Attenuates the Relative Blood Volume Drop Due to Intravascular Volume Loss during Hemodiafiltration

Abstract

<b><i>Introduction:</i></b> Patients in hemodiafiltration (HDF) eliminate volume overload by ultrafiltration. Vascular volume loss is among the main mechanisms contributing to adverse events such as intradialytic hypotension. Here, we hypothesize that the intradialytic exercise (IDEX) is an intervention that could improve the acute response of physiological mechanisms involved during vascular volume loss. To test this hypothesis, we evaluated the hemodynamic response to mild aerobic exercise during HDF. <b><i>Methods:</i></b> Nineteen end-stage renal disease (ESRD) patients (11 women: 40 ± 10.8 years old, and 8 men: 42 ± 21 years old) receiving HDF thrice a week, with 6 months of previous physical conditioning, participated in this study. Three HDF sessions were scheduled for each patient: 1 resting in supine position, 1 resting in sitting position, and 1 doing aerobic exercise. The first 2 sessions were taken as control. The ultrafiltration rate was set to 800 mL/h in each session. The hemodynamic response was monitored through the relative blood volume (RBV), and cardiovascular variables measured noninvasively by photoplethysmography. Adequacy variables such as Kt/V and percentage reduction of urate, urea, creatinine (Cr), and phosphate were also monitored. <b><i>Findings:</i></b> The decrease rate of the RBV was smaller in the session with IDEX compared to the sessions with no exercise. No differences were found neither in the cardiovascular variables nor in the adequacy variables among the 3 sessions. There were no hypotension events during the session with exercise, and 8 events during the sessions without exercise (<i>p</i> = 0.002). <b><i>Discussion:</i></b> Mild exercise during HDF decreased the RBV drop and was associated with less hypotension events. The lack of differences in the hemodynamic variables suggests an adequate acute response of cardiovascular compensation variables to intradialytic hypovolemia.

Hemodiafiltration in developing countries

“…28 In Mexico, an experimental study using low-intensity intradialytic exercise during regular HDF thrice a week for at least 6 months showed the potential to decrease the relative blood volume drop and was associated with less hypotension due to intravascular volume loss. 29 In Brazil, the HDFIT study, a multi-center prospective randomized-controlled trial, investigated the impact of a short exercise training program for patients treated with HDF compared to high-flux HD. Although the main outcome and post-hoc analysis reported no significant effect on physical activity and self-reported sleep duration, 30,31 a convective volume of >22 L/session for 6 months was associated with increased Kt/V and decreased phosphate.…”

“…In Mexico, an experimental study using low‐intensity intradialytic exercise during regular HDF thrice a week for at least 6 months showed the potential to decrease the relative blood volume drop and was associated with less hypotension due to intravascular volume loss 29 …”