The International journal of artificial organs, 2000
A new polymer-based sorbent cartridge has been recently developed for enhancing middle molecule r... more A new polymer-based sorbent cartridge has been recently developed for enhancing middle molecule removal during hemodialysis. The cartridge (Betasorb, Renaltech, New York, USA) has been designed to be placed in series with the dialyzer in the blood circuit. It is therefore important to evaluate the distribution of flow into the blood compartment of the device in order to assess if the surface of the sorbent is utilized to the best. For this purpose, a special imaging technique was utilized. Cartridges were analyzed during a simulated in vitro circulation at 250 and 350 ml/min of blood flow and 25% and 40% hematocrit. Cartridges were placed in vertical position and a cross longitudinal section 1 cm thick was analyzed in sequence by a helical scanner. Dye was injected into the arterial inlet and the progressive distribution was evaluated by sequential densitometrical measures carried out automatically by the machine. The sequential images analyzed by the scanner demonstrated excellent ...
Journal of the American Society of Nephrology : JASN, 1998
Although the use of cooled dialysate during hemodialysis is associated with stabilization of intr... more Although the use of cooled dialysate during hemodialysis is associated with stabilization of intradialytic BP, the effects of blood cooling on hemodynamics and urea kinetics in high-efficiency hemodialysis have not been completely studied. In particular, the effects of blood cooling have not been elucidated in very short-time, high K/V dialysis treatments, in which postdialysis urea rebound is maximized. In theory, blood cooling could increase urea compartmentalization during treatment and decrease dialysis efficacy. Measurements of cardiovascular hemodynamics and urea kinetics were performed in 15 patients (56 studies) during dialysis, using a blood temperature monitor with control of dialysate temperature. Dialysate temperature was adjusted to either lower the core temperature or raise the core temperature by, respectively, producing negative heat-energy exchange (cooled dialysis) or keeping heat-energy exchange in the extracorporeal circuit neutral (thermoneutral dialysis) so tha...
The aim of the study was to investigate whether body mass index (BMI) influences the estimation o... more The aim of the study was to investigate whether body mass index (BMI) influences the estimation of extracellular volume (ECV) in hemodialysis (HD) patients when using segmental bioimpedance analysis (SBIA) compared to wrist-to-ankle bioimpedance analysis (WBIA) during HD with ultrafiltration (UF). Twenty five HD patients (M:F 19:6,) were studied, and further subdivided into two groups of patients, one group with a high BMI (25 kg m-2) and the other with a low BMI (<25 kg m-2). Segmental (arm, trunk, leg) and wrist-to-ankle bioimpedance measurements on each patient were performed using a modified Xitron 4000B system (Xitron Technologies, San Diego, CA). No differences in extracellular resistance (R(E), ohms) between wrist-to-ankle (R(W)) and sum of segments (R(S)) were noted for either the high BMI (489.2+/-82 ohm versus 491.6+/-82 ohm, p=ns) or low BMI groups (560.8+/-77 ohm versus 557.5+/-75 ohm, p=ns). UF volume (UFV, liters) did not differ significantly between the groups (4.0+/-0.9 L versus 3.3+/-1.0 L, p=ns), but change in ECV (DeltaECV) differed not only between methods: WBIA versus SBIA in the high BMI group (2.74+/-1.1 L versus 3.64+/-1.4 L, p<0.001) and in the low BMI group (1.86+/-0.9 L versus 2.91+/-1.0 L, p<0.05) but also between the high and lower BMI groups with WBIA (2.74+/-1.1 L versus 1.86+/-0.9 L, p<0.01). However, there was no significant difference in SBIA between BMI groups. This study suggests that the segmental bioimpedance approach may more accurately reflect changes in ECV during HD with UF than whole body impedance measurements.
Background. Ultra®ltration (UF) is assumed to enhance urea removal during haemodialysis (HD) beca... more Background. Ultra®ltration (UF) is assumed to enhance urea removal during haemodialysis (HD) because of convective transport and because of contraction of urea distribution volume. However, UF-induced blood volume reduction has been hypothesized to enhance peripheral urea sequestration and post-dialysis urea rebound (PDUR), possibly reducing HD effectiveness. The effect of UF on PDUR was investigated in this study. Methods. Nine HD patients were studied on two subsequent treatment days. The ®rst HD was performed with UF (UF-rate 0.78"0.27 luh), and the second treatment without UF. Serial measurements of serum water urea nitrogen concentration, arterial blood pressures (BP), and relative blood volume changes (DBV%) were obtained over the duration of HD.
Continuous renal replacement therapies (CRRT) are today considered a well-tolerated and efficient... more Continuous renal replacement therapies (CRRT) are today considered a well-tolerated and efficient group of treatments for acute renal failure in critically ill patients [112]. The evolution in technology of CRRT has only partially followed the more sophisticated evolution that took place in the ...
The increase in patient temperature during hemodialysis is explained by hemodynamic compensation ... more The increase in patient temperature during hemodialysis is explained by hemodynamic compensation during ultrafiltration and hypovolemia that leads to peripheral vasoconstriction and reduced heat losses. We analyzed 51 stable high-efficiency hemodialysis treatments in 27 patients during isothermic dialysis in which body temperature was maintained at a constant level (؎0.1°C) using the temperature-control option of the Blood Temperature Monitor (BTM; Fresenius Medical Care, Bad Homburg, Germany). Hemodialysis was delivered using ultrapure water (limulus amebocyte lysate test < 0.06 endotoxin units/mL) at mean blood flows of 410 ؎ 40 mL/min. During treatments lasting 178 ؎ 23 minutes, 4.8% ؎ 1.4% of postdialysis body weight (W%) and 9.5% ؎ 2.5% of postdialysis body water were removed using mean ultrafiltration rates of 1.1 ؎ 0.3 L/h. Dialysate temperatures significantly decreased from 35.9°C ؎ 0.3°C to 35.6°C ؎ 0.6°C during hemodialysis. During these treatments, 187 ؎ 69 kJ of thermal energy were removed from the patients through the extracorporeal circulation using cool dialysate. Extracorporeal heat flow was 17 ؎ 6 W. Energy expenditure (H) estimated from anthropometric data was 65 ؎ 12 W. Thus, 28% ؎ 10% of estimated energy expenditure (H%) was removed during isothermic dialysis. A highly significant correlation was observed between H% and W% (H% ؍ -5.6 * W%; r 2 ؍ 0.91; P < 0.0001). This result is in support of the volume hypothesis of intradialytic heat accumulation and provides a rule of thumb to estimate extracorporeal cooling requirements for isothermic dialysis. Approximately 6% of H must be removed through the extracorporeal circulation for each percent of ultrafiltration-induced body-weight change. The importance of body temperature control during hemodialysis increases with increased ultrafiltration requirements.
Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysi... more Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysis (MHD) patients. The Transonic (TRS; Transonic Systems, Ithaca, NY) device is frequently used for determination of cardiac output (CO) by an indicator dilution technique. The Task Force Monitor (TFM; CN Systems, Graz, Austria) has gained attention as noninvasive tool for continuous beat-to-beat assessment of cardiovascular variables, including CO by impedance cardiography. Despite its use in cardiology and intensive care settings, the TFM has yet not been validated in dialysis patients.
The International journal of artificial organs, 2000
A new polymer-based sorbent cartridge has been recently developed for enhancing middle molecule r... more A new polymer-based sorbent cartridge has been recently developed for enhancing middle molecule removal during hemodialysis. The cartridge (Betasorb, Renaltech, New York, USA) has been designed to be placed in series with the dialyzer in the blood circuit. It is therefore important to evaluate the distribution of flow into the blood compartment of the device in order to assess if the surface of the sorbent is utilized to the best. For this purpose, a special imaging technique was utilized. Cartridges were analyzed during a simulated in vitro circulation at 250 and 350 ml/min of blood flow and 25% and 40% hematocrit. Cartridges were placed in vertical position and a cross longitudinal section 1 cm thick was analyzed in sequence by a helical scanner. Dye was injected into the arterial inlet and the progressive distribution was evaluated by sequential densitometrical measures carried out automatically by the machine. The sequential images analyzed by the scanner demonstrated excellent ...
Journal of the American Society of Nephrology : JASN, 1998
Although the use of cooled dialysate during hemodialysis is associated with stabilization of intr... more Although the use of cooled dialysate during hemodialysis is associated with stabilization of intradialytic BP, the effects of blood cooling on hemodynamics and urea kinetics in high-efficiency hemodialysis have not been completely studied. In particular, the effects of blood cooling have not been elucidated in very short-time, high K/V dialysis treatments, in which postdialysis urea rebound is maximized. In theory, blood cooling could increase urea compartmentalization during treatment and decrease dialysis efficacy. Measurements of cardiovascular hemodynamics and urea kinetics were performed in 15 patients (56 studies) during dialysis, using a blood temperature monitor with control of dialysate temperature. Dialysate temperature was adjusted to either lower the core temperature or raise the core temperature by, respectively, producing negative heat-energy exchange (cooled dialysis) or keeping heat-energy exchange in the extracorporeal circuit neutral (thermoneutral dialysis) so tha...
The aim of the study was to investigate whether body mass index (BMI) influences the estimation o... more The aim of the study was to investigate whether body mass index (BMI) influences the estimation of extracellular volume (ECV) in hemodialysis (HD) patients when using segmental bioimpedance analysis (SBIA) compared to wrist-to-ankle bioimpedance analysis (WBIA) during HD with ultrafiltration (UF). Twenty five HD patients (M:F 19:6,) were studied, and further subdivided into two groups of patients, one group with a high BMI (25 kg m-2) and the other with a low BMI (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;25 kg m-2). Segmental (arm, trunk, leg) and wrist-to-ankle bioimpedance measurements on each patient were performed using a modified Xitron 4000B system (Xitron Technologies, San Diego, CA). No differences in extracellular resistance (R(E), ohms) between wrist-to-ankle (R(W)) and sum of segments (R(S)) were noted for either the high BMI (489.2+/-82 ohm versus 491.6+/-82 ohm, p=ns) or low BMI groups (560.8+/-77 ohm versus 557.5+/-75 ohm, p=ns). UF volume (UFV, liters) did not differ significantly between the groups (4.0+/-0.9 L versus 3.3+/-1.0 L, p=ns), but change in ECV (DeltaECV) differed not only between methods: WBIA versus SBIA in the high BMI group (2.74+/-1.1 L versus 3.64+/-1.4 L, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.001) and in the low BMI group (1.86+/-0.9 L versus 2.91+/-1.0 L, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05) but also between the high and lower BMI groups with WBIA (2.74+/-1.1 L versus 1.86+/-0.9 L, p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). However, there was no significant difference in SBIA between BMI groups. This study suggests that the segmental bioimpedance approach may more accurately reflect changes in ECV during HD with UF than whole body impedance measurements.
Background. Ultra®ltration (UF) is assumed to enhance urea removal during haemodialysis (HD) beca... more Background. Ultra®ltration (UF) is assumed to enhance urea removal during haemodialysis (HD) because of convective transport and because of contraction of urea distribution volume. However, UF-induced blood volume reduction has been hypothesized to enhance peripheral urea sequestration and post-dialysis urea rebound (PDUR), possibly reducing HD effectiveness. The effect of UF on PDUR was investigated in this study. Methods. Nine HD patients were studied on two subsequent treatment days. The ®rst HD was performed with UF (UF-rate 0.78"0.27 luh), and the second treatment without UF. Serial measurements of serum water urea nitrogen concentration, arterial blood pressures (BP), and relative blood volume changes (DBV%) were obtained over the duration of HD.
Continuous renal replacement therapies (CRRT) are today considered a well-tolerated and efficient... more Continuous renal replacement therapies (CRRT) are today considered a well-tolerated and efficient group of treatments for acute renal failure in critically ill patients [112]. The evolution in technology of CRRT has only partially followed the more sophisticated evolution that took place in the ...
The increase in patient temperature during hemodialysis is explained by hemodynamic compensation ... more The increase in patient temperature during hemodialysis is explained by hemodynamic compensation during ultrafiltration and hypovolemia that leads to peripheral vasoconstriction and reduced heat losses. We analyzed 51 stable high-efficiency hemodialysis treatments in 27 patients during isothermic dialysis in which body temperature was maintained at a constant level (؎0.1°C) using the temperature-control option of the Blood Temperature Monitor (BTM; Fresenius Medical Care, Bad Homburg, Germany). Hemodialysis was delivered using ultrapure water (limulus amebocyte lysate test < 0.06 endotoxin units/mL) at mean blood flows of 410 ؎ 40 mL/min. During treatments lasting 178 ؎ 23 minutes, 4.8% ؎ 1.4% of postdialysis body weight (W%) and 9.5% ؎ 2.5% of postdialysis body water were removed using mean ultrafiltration rates of 1.1 ؎ 0.3 L/h. Dialysate temperatures significantly decreased from 35.9°C ؎ 0.3°C to 35.6°C ؎ 0.6°C during hemodialysis. During these treatments, 187 ؎ 69 kJ of thermal energy were removed from the patients through the extracorporeal circulation using cool dialysate. Extracorporeal heat flow was 17 ؎ 6 W. Energy expenditure (H) estimated from anthropometric data was 65 ؎ 12 W. Thus, 28% ؎ 10% of estimated energy expenditure (H%) was removed during isothermic dialysis. A highly significant correlation was observed between H% and W% (H% ؍ -5.6 * W%; r 2 ؍ 0.91; P < 0.0001). This result is in support of the volume hypothesis of intradialytic heat accumulation and provides a rule of thumb to estimate extracorporeal cooling requirements for isothermic dialysis. Approximately 6% of H must be removed through the extracorporeal circulation for each percent of ultrafiltration-induced body-weight change. The importance of body temperature control during hemodialysis increases with increased ultrafiltration requirements.
Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysi... more Cardiovascular disease is the leading cause of morbidity and mortality in maintenance hemodialysis (MHD) patients. The Transonic (TRS; Transonic Systems, Ithaca, NY) device is frequently used for determination of cardiac output (CO) by an indicator dilution technique. The Task Force Monitor (TFM; CN Systems, Graz, Austria) has gained attention as noninvasive tool for continuous beat-to-beat assessment of cardiovascular variables, including CO by impedance cardiography. Despite its use in cardiology and intensive care settings, the TFM has yet not been validated in dialysis patients.
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