Evidence of Profiled Hemodialysis Efficacy in the Treatment of Intradialytic Hypotension

Abstract

In the last 10 years the percentage of dialysis patients suffering from clinical intradialytic intolerance has greatly increased. Profiled hemodialysis (PHD) is a new technical approach, alternative to standard hemodialysis (SHD) for the treatment of intradialytic symptomatic hypotension. It is based on intradialytic modulation of the dialysate sodium concentration, using a dialysate sodium concentration profile elaborated by a new mathematical kinetic model. The aim of PHD is to reduce the intradialytic blood volume decrease, thanks to a dialysate sodium profile, which allows a reduction in the plasma osmolarity decrease, thereby boosting intravascular fluid refilling. This work aims at clinically validating the PHD technique, by testing its ability against SHD, to maintain a more stable intradialytic blood volume; this evaluation was supported by monitoring some hemodynamic parameters. Twelve dialysis patients on SHD treatment were selected because of their intradialytic symptomatic hypotension. Twelve SHD (one per patient) and 12 PHD sessions (one per patient) were performed to achieve the same sodium mass removal and body weight decrease on both PHD and SHD. During these sessions we monitored the blood volume variation % by the crit-line (a non invasive blood volume monitoring device), the mean blood pressure and heart rate directly and, finally, the stroke volume and cardiac output indirectly by bidimensional doppler-echocardiography. Comparison of the results obtained with the two techniques shows PHD to achieve a significantly more stable blood volume, blood pressure and cardiovascular function than SHD, in particular during the second and the third hour of the dialysis session.

Does Bicarbonate Transfer Have Relevant Hemodynamic Consequences in Standard Hemodialysis?

“…Confi rming these data, an intradialytic hemodynamic instability with hypotension resulting from alkalemia has been observed in two previous studies (the second of them done in our dialysis unit) performed with either an unusually high (40 mmol/l) or a standard (32 mmol/l) bicarbonate concentration in the dialysis fl uid [19,20] . As a consequence, even though the correction of chronic metabolic acidosis is an important goal of dialysis, in patients showing a signifi cant peri-and post-dialysis alkalemia and in the event of failure of the classical tools to prevent intradialytic hypotension, such as sodium profi ling, blood temperature and on-line blood volume monitoring [21,22] , it was suggested to consider a reduction in the bicarbonate concentration of the dialysis fl uid [20] .…”

Sodium Prescription in the Prevention of Intradialytic Hypotension: New Insights into an Old Concept

“…1). The model is applied to calculate sodium and ultrafiltration profiles as concave downward curves whose apices correspond to 60 min after the start of the dialysis session [31]. These profiles are computed from the patient's initial data: session timing, body weight to be lost, predialysis concentration of sodium and urea, and the end-dialysis sodium target.…”

“…The excess fluid is drained from the intracellular compartment and can be removed by means of a high ultrafiltration rate, thereby achieving most of the weight loss required. During the second half of the dialysis session, the ultrafiltration rate is automatically reduced together with the sodium profile to allow excess sodium removal [31]. The Profiler was successfully validated in experiments and proved to give accurate descriptions of solute kinetics during the dialysis session, maintaining the strategy to increase the ECV/ICV ratio [31].…”

“…During the second half of the dialysis session, the ultrafiltration rate is automatically reduced together with the sodium profile to allow excess sodium removal [31]. The Profiler was successfully validated in experiments and proved to give accurate descriptions of solute kinetics during the dialysis session, maintaining the strategy to increase the ECV/ICV ratio [31]. Considering that there are osmotic sodium and non-osmotic body sodium stores, the Profiler mathematical model was revised and the intracellular sodium compartment was included in the model with a detailed description of interstitial elastance and interstitial fluid pressure [32,33].…”

Evaluation of Intradialytic Solute and Fluid Kinetics

“…This improved version of the model enables sodium and ultrafiltration profiles to be elaborated more exactly and this leads to a better clinical response by the patient than was achieved by PHD based on the previous version of the model [3].…”