Does a reduction in dialysate sodium improve blood pressure control in haemodialysis patients?

Introduction: There has been debate as to the value of lower sodium dialysates to control blood pressure in haemodialysis patients, as sodium is predominantly removed by ultrafiltration. Methods: Re‐audit of clinical practice following reduction in dialysate sodium concentration. Results: Overall dialysate sodium concentration decreased from 138.9 ± 1.7 to 137.8 ± 1.7 mmol/L (mean ± standard deviation), resulting in a reduction in pre‐ and post‐dialysis mean arterial pressure (MAP) of 4 mmHg (from 100.6 ± 15.6 to 97.1 ± 15.6, P < 0.01 and from 91.7 ± 15.6 to 87.1 ± 14.6, P < 0.001 respectively), yet fewer patients were prescribed antihypertensives (49.6 vs 60.6%), and less antihypertensive medications/patient (mean 0.86 vs 1.05), ultrafiltration requirements (2.8% vs 3.2% body weight, P < 0.001), and symptomatic intradialytic hypotension (0.19 vs 0.28 episodes per week, P < 0.001). A multivariable model showed that for a dialysate sodium of 136 mmol/L, younger patients had higher MAP than older patients (0.35 mmHg lower MAP/year older; but with a dialysate sodium of 140 mmol/L, there was minimal association of MAP with age (0.07 mmHg higher MAP/year older). Conclusion: Change in clinical practice, amounting to a modest reduction in dialysate sodium was associated with a reduction not only in pre‐ and post‐dialysis blood pressures, but also ultrafiltration requirements and symptomatic intradialytic hypotension. However, this effect on blood pressure was most marked for older patients and women, within minimal effects for younger patients, and lesser effects for men, suggesting that dialysate sodium reduction alone may help improve blood pressure control, but requires additional factors such as dietary sodium restriction to be effective in younger male patients.     

Impact of sodium and ultrafiltration profiling on hemodialysis-related symptoms

Dialysate sodium and ultrafiltration profiling are two methods to reduce symptoms during hemodialysis. The objective of the study was to determine the efficacy of combining these techniques to reduce symptoms in chronic hemodialysis patients. Blood volume changes were measured to determine whether any benefit of profiling could be explained through this mechanism. Patients were randomized to profiled dialysate sodium and ultrafiltration or constant dialysate sodium and ultrafiltration. The study was a two-period, two-treatment, crossover design with repeated measures. The primary outcome was hypotension and/or symptomatic events observed by the dialysis nurse. Secondary outcomes were symptom survey scores, weights, BP, and blood volume changes. Thirty-three patients were randomized. On standard treatment, 30.6% of dialysis sessions were symptomatic compared with 20.4% on profiled treatments. The odds ratio for the development of hypotension or symptomatic event on profiled treatments was 0.61 (95% confidence interval, 0.39 to 0.96) compared with standard treatment. Patients had lower symptom scores by questionnaire in both the intradialytic and the interdialytic periods during profiled treatments. Predialysis weight was greater during profiled treatments by 0.3 kg (P: = 0.008), but there were no differences in postdialysis weight, BP, or thirst. There was no difference in maximum decrease in blood volume during the two treatments (standard, -11.2%; profiled, -10.0%; P: = 0.08), but there was a significant difference in the rate of change in blood volume (standard, -2.96%/h; profiled, -1.96%/h; P: < 0.001). Decrease in blood volume, rate of change in blood volume, and predialysis weights were not associated with hypotension or symptomatic dialysis sessions. In conclusion, dialysate sodium and ultrafiltration profiling significantly reduces hemodialysis-related symptoms. Profiling reduces the slope of the blood volume curve during dialysis, but blood volume changes are not predictive of symptomatic events for an individual patient.     

Impact of sodium and ultrafiltration profiling on haemodialysis-related hypotension.

BACKGROUND: Symptomatic hypotension is the most frequent complication in patients receiving haemodialysis (HD). Previous studies have reported that the use of modulating dialysate sodium concentration or ultrafiltration (UF) rates, or the combination use of sodium profile and UF profile may better preserve blood volume and reduce the incidence of hypotensive episodes. The aim of this study was to evaluate the effects of sodium balance-neutral sodium profile and UF profile and their combination on preservation of blood volume, cardiac function and occurrence of hypotensive episodes. METHODS: Using Fresenius MC 4008S, eight stable HD patients underwent four treatments: (1) control, constant dialysate sodium concentration of 138 mmol/l with constant UF; (2) sodium profile, a linearly decreasing dialysate sodium concentration (148-131 mmol/l) with constant UF; (3) UF profile, a linearly decreasing UF rate with dialysate sodium concentration of 138 mmol/l; (4) sodium+UF profile, combination of sodium and UF profile. Each treatment was applied in 10 dialysis sessions. Relative blood volume (RBV), mean blood pressure (MBP), heart rate (HR), interior vena cava diameter (IVCD), stroke volume (SV), cardiac output (CO), plasma sodium concentration and the frequency of symptomatic hypotension were monitored. RESULTS: There were no significant differences in the IVCD, MBP, SV, CO and body weight before dialysis between the three profiles and the control. The total plasma protein, haemoglobin, and intradialytic sodium mass removal showed similar results. Compared with the control, better preservation of RBV and MBP at 4 and 5 h and a higher stability in SV variation, but larger UF volume were achieved during sodium+UF profile (P<0.05, respectively), the incidence of intradialytic hypotension was significantly reduced (P<0.05). CONCLUSIONS: With the similar intradialytic sodium removal, during sodium balance-neutral linearly decreasing sodium profile combined with linearly decreasing UF profile, greater intradialytic stability of the blood volume, blood pressure and cardiac function could be obtained, and hypotensive episodes were significantly reduced.     

Profiled hemodialysis reduces intradialytic symptoms

A prospective study on the effect of profiled hemodialysis on intradialytic symptoms was undertaken among patients recruited between September 2002 and December 2002. Evaluated intradialytic symptoms included hypotension, muscle cramps, dizziness, headache, nausea, discomfort, thirst, and shortness of breath. Symptomatic patients were allocated to one mode of combined sodium and ultrafiltration profile during hemodialysis. The programs were readily available on Fresenius MC 4008 H&E hemodialysis machines. Evaluation was performed before profiling and at 2, 4, and 6 weeks into the profiled hemodialysis. On standard hemodialysis 40 (36.4%) patients were symptomatic. Hypotension was reported in 29 (72.5%) of patients receiving standard treatment. Dizziness, headache, and muscle cramps were reported in 22 (55%), 15 (37.5%), and 9 (22.5%) patients, respectively. These symptoms were significantly (P <.05) improved at 2, 4, and 6 weeks of profiling. Other symptoms, such as discomfort, nausea, vomiting, and thirst, were infrequently reported among patients without or with profiling. There was no significant difference between the applied profiles when compared with each other. In conclusion, sodium and ultrafiltration profiling are effective techniques to reduce acute adverse side effects of hemodialysis. They improve patient well-being and dialysis tolerance, minimize interventions during dialysis.     

Clinical Use of Profiled Hemodialysis

The new population on dialysis today consists mainly of high risk patients (the elderly, diabetics, etc.) with high cardiovascular scores, and such vascular pathology is the most important predisposing factor for the occurrence of a frequent intradialytic clinical complication, vascular instability syndrome, which covers a range of clinical problems. Recently a new dialysis technique, profiled hemodialysis (PHD), has been set up and proposed for routine use. PHD consists of the clinical use of preestablished individual dialysis profiles aimed at antagonizing the changes in intradialytic plasma osmolarity by continuous modulation of dialysate sodium concentration throughout the whole extracorporeal session. In particular, PHD aims at reducing the fall of plasma osmolarity in the first half of the session (when it is higher) by reducing the sodium removal rate through increasing its dialysate concentration while taking into account the desired individual sodium balance to be reached at the end of the session. In this work, we report clinical experience with PHD compared to standard hemodialysis with constant sodium dialysate (SHD) in terms of its efficacy to maintain a more stable intradialytic blood volume (BV) and more stable hemodynamics. The PHD used in this work has been implemented by a mathematical model for computing the individual dialysate sodium profile which we have recently validated (Ursino M, Colì L, La Manna G, Grilli Cicilioni M, Dalmastri V, Guidicissi A, Masotti P, Avanzolini G, Stefani S, Bonomini V. A simple mathematical model of intradialytic sodium kinetics: “in vivo” validation during hemodialysis with constant or variable sodium. Int J Artif Organs 1996; 19:393–403.). Eleven uremic patients affected by hypotension at the beginning of dialysis treatment were studied. Each patient first underwent an SHD treatment and 1 week later a PHD treatment. The 2 extracorporeal sessions (one on SHD and the other on PHD) were performed in each individual patient under identical operative conditions including the sodium mass removal by the end of the session and the ultrafiltration rate. The crit line and Doppler echocardiography were used to determine BV, cardiac output (CO), and stroke volume (SV) throughout the sessions. The mean blood pressure (MBP) and heart rate (HR) were simultaneously monitored. PHD was associated with a more stable intradialytic BV and more stable hemodynamics compared to SHD. The higher stability of BV and cardiac function (in terms of SV and CO maintenance) which was obtained above all in the first half of the PHD session was associated with a higher stability of the MBP and the HR. This resulted in an enhancement in cardiovascular tolerance to ultrafiltration throughout the session in all tested patients. In contrast, SHD in the same patients was characterized by early significant changes in BV and cardiovascular parameters resulting in a significant decrease of the MBP and a significant increase of the HR throughout the session and also 1 h after the end of dialysis. Our results indicate that PHD may represent an efficient approach for the treatment of patients suffering from intradialytic vascular instability. If long-term clinical practice confirms the efficacy of PHD in controlling dialysis intolerance symptoms, it will have great scope as a routine procedure.     

High and low sodium acetate haemodialysis and ultrafiltration

This study was undertaken to evaluate the effect of increasing the dialysate sodium concentration on haemodynamic effects, arterial blood gases and chemistries during haemodialysis and ultrafiltration. Significant changes in mean blood pressure (MBP) and heart rate (HR) were not noted; but significant differences in sodium, potassium, total protein concentration, haematocrit and plasma osmolality during dialysis and ultrafiltration were found with both dialysates. Significant differences were also noted in pCO₂ during dialysis and ultrafiltration with both dialysates and increase of pH during dialysis with low sodium dialysate. Significant changes in kind and frequency of unpleasant symptoms were found with both dialysates.     

A simple mathematical model applied to selection of the sodium profile during profiled haemodialysis

Background. Among dialysis patients in the last 10 years the incidence of intradialytic dysequilibrium syndrome and symptomatic hypotension has increased significantly. Profiled haemodialysis (PHD), a new dialysis technique based on intradialytic modulation of the dialysate sodium concentration according to pre-elaborated individual profiles, has been set up to reduce intradialytic imbalances and the incidence of dysequilibrium syndrome and symptomatic hypotension. The present paper illustrates a new mathematical model for solute kinetics, single-compartment for sodium profile to be elaborated a priori, before each dialysis session, according to the patient's clinical needs and respecting the individual sodium mass removal and weight gain. Method. The mathamatical model was first derived and then applied to determining a rational dialysate sodium profile. A procedure which allows the method to be tuned to individual clinical needs on the basis of routine measurements performed before each session is also presented. The proposed method was validated in vivo during seven dialysis sessions, each performed on a different patient. Results. The comparison between data predicted by the model and those obtained in vivo shows a good correspondence in particular concerning the time pattern of blood urea and sodium. The comparison between the model prediction and in vivo determined sodium and urea plasma curves showed standard deviations (2.25 mEq/l for sodium and 0.87 mmol/l for urea) only slightly higher than those attributable to laboratory measurement errors. Moreover, in vivo implementation of PHD by our model enables one to remove an amount of sodium mass comparable with the a priori quantity predicted by the model.     

Automated individualization of dialysate sodium concentration reduces intradialytic plasma sodium changes in hemodialysis

In standard care, hemodialysis patients are often treated with a center‐specific fixed dialysate sodium concentration, potentially resulting in diffusive sodium changes for patients with plasma sodium concentrations below or above this level. While diffusive sodium load may be associated with thirst and higher interdialytic weight gain, excessive diffusive sodium removal may cause intradialytic symptoms. In contrast, the new hemodialysis machine option “Na control” provides automated individualization of dialysate sodium during treatment with the aim to reduce such intradialytic sodium changes without the need to determine the plasma sodium concentration. This proof‐of‐principle study on sodium control was designed as a monocentric randomized controlled crossover trial: 32 patients with residual diuresis of ≤1000 mL/day were enrolled to be treated by high‐volume post‐dilution hemodiafiltration (HDF) for 2 weeks each with “Na control” (individually and automatically adjusted dialysate sodium concentration) versus “standard fixed Na” (fixed dialysate sodium 138 mmol/L), in randomized order. Pre‐ and post‐dialytic plasma sodium concentrations were determined at bedside by direct potentiometry. The study hypothesis consisted of 2 components: the mean plasma sodium change between the start and end of the treatment being within ±1.0 mmol/L for sodium‐controlled treatments, and a lower variability of the plasma sodium changes for “Na control” than for “standard fixed Na” treatments. Three hundred seventy‐two treatments of 31 adult chronic hemodialysis patients (intention‐to‐treat population) were analyzed. The estimate for the mean plasma sodium change was ?0.53 mmol/L (95% confidence interval: [?1.04; ?0.02] mmol/L) for “Na control” treatments and ?0.95 mmol/L (95% CI: [?1.76; ?0.15] mmol/L) for “standard fixed Na” treatments. The standard deviation of the plasma sodium changes was 1.39 mmol/L for “Na control” versus 2.19 mmol/L for “standard fixed Na” treatments (P = 0.0004). Whereas the 95% CI for the estimate for the mean plasma sodium change during “Na control” treatments marginally overlapped the lower border of the predefined margin ±1.0 mmol/L, the variability of intradialytic plasma sodium changes was lower during “Na control” versus “standard fixed Na” treatments. Thus, automated dialysate sodium individualization by “Na control” approaches isonatremic dialysis in the clinical setting.     

Serum chromogranin A concentration and intradialytic hypotension in chronic haemodialysis patients

Aim The aim of this study was to investigate the influence of haemodialysis on plasma chromogranin A (CgA) concentration and to assess the relationship between CgA, blood pressure, occurrence of intradialytic hypotension episodes and residual renal function, respectively. Methods The study included 38 chronic haemodialysis patients (24 M, 14 F; mean age 56.2 ± 13.6 years). Plasma CgA and blood pressure were measured before and after a mid-week dialysis. Control group included 10 age- and sex-matched healthy subjects. Results Plasma CgA levels were on average 50-fold higher in HD patients than in the controls (699 ± 138 vs. 14 ± 6 U/L). In HD patients plasma CgA corrected for ultrafiltration rates significantly increased (to 836 ± 214 U/L, P < 0.001) at the end of dialysis procedure. In patients with (n = 8) and without frequent symptomatic intradialytic hypotension episodes predialysis values of CgA were similar (701 ± 169 vs. 698 ± 132 U/L) but post-dialysis were significantly lower in the former group (746 ± 312 vs. 860 ± 177 U/L; P = 0.03) despite a similar rate of ultrafiltration (2675 ± 1009 and 2583 ± 1311 ml, respectively). Accordingly, in patients with intradialytic hypotension an increase of plasma CgA during dialysis was also much lower than in patients without hypotension (45 ± 81 vs. 163 ± 144 U/L; P = 0.001). Conclusions CgA undergoes marked accumulation in renal failure. The increase of plasma CgA during dialysis is impaired in subjects with intradialytic hypotension episodes, which confirms the role of autonomic dysfunction in the pathogenesis of this complication.     

Unexpected haemodynamic instability associated with standard bicarbonate haemodialysis.

BACKGROUND: The bicarbonate concentration in dialysis fluids for intermittent haemodialysis usually is between 32 and 35 mmol/l. The severity of chronic metabolic acidosis secondary to end-stage renal failure is very variable, however, so that in some patients pre-dialysis acidosis is overcorrected. This study aimed to analyse haemodynamic tolerances to metabolic alkalosis during intermittent haemodialysis. METHODS: In this randomized controlled trial with a single blind, cross-over design, we used dialysis liquids with two different bicarbonate concentrations, 32 (modality A) and 26 (modality B) mmol/l, and in 26 patients, 468 dialysis sessions, compared blood pressure, heart rate, incidence of hypotension and the frequency of corrections required with saline or hypertonic glucose infusions. RESULTS: The results of intradialytic haemodynamic monitoring for modalities A and B, respectively, were: lowest systolic blood pressure 120.8+/-20.8 vs 124.3+/-20.6 mmHg (P < 0.01); mean systolic blood pressure 138.5+/-23.8 vs 144.6+/-24.8 mmHg (P < 0.001); and highest heart rate 73.5+/-12.0 vs 75.8 +/- 12.9 (NS); with modality A, patients had more dialysis sessions with hypotensive episodes (5.55 vs 1.7%, P < 0.05) and required more saline or hypertonic glucose infusions (20.9 vs 13.7% of the dialysis sessions, P < 0.05). CONCLUSIONS: Mild metabolic alkalosis resulting from standard bicarbonate haemodialysis (32 mmol/l) may induce symptomatic hypotension. While normalizing chronic metabolic acidosis is desirable, reducing bicarbonate concentrations should be considered in cases of significant alkalaemia or otherwise untreatable haemodynamic instability.     

A double-blind evaluation of sodium gradient hemodialysis

In a double-blind, crossover trial, 7 chronic hemodialysis patients underwent three 4-week treatment periods. During one period, dialysate contained 135 mEq/l sodium. During another period, dialysate contained 143 mEq/l sodium. During the remaining period, we used "sodium gradient' dialysate, the sodium concentration of which was decreased from 160 to 133 mEq/l during each 4-hour dialysis session. Ultrafiltration was performed at a constant rate to achieve a predetermined post-dialysis weight. Interdialytic weight gain, thirst, blood pressure control, and incidence of side effects were monitored. There was a significant difference in interdialytic weight gain for the 3 treatments (p = 0.005). Interdialytic weight gain using 135 mEq/l sodium dialysate (2.2 +/- 0.9 kg, mean +/- SD) was significantly less than that using either 143 mEq/l sodium dialysate (2.6 +/- 0.8 kg) or sodium gradient dialysate (2.8 +/- 0.7 kg). Self-reported thirst tended to be less severe with 135 mEq/l sodium dialysate than with 143 mEq/l sodium dialysate or with sodium gradient dialysate, but changes in thirst were not statistically significant (p = 0.13). The incidence of intradialytic hypotensive episodes was comparable with the 3 levels of dialysate sodium. The results suggest that the described sodium gradient method does not prevent the increased interdialytic weight gain and thirst seen with other forms of high-sodium dialysis, and probably does not reduce the incidence of side effects.     

Low sodium haemodialysis reduces interdialytic fluid consumption but paradoxically increases post-dialysis thirst.

BACKGROUND: Interdialytic weight gain (IDWG) can be reduced by lowering the dialysate sodium concentration ([Na]) in haemodialysis patients. It has been assumed that this is because thirst is reduced, although this has been difficult to prove. We compared thirst patterns in stable haemodialysis patients with high and low IDWG using a novel technique and compared the effect of low sodium dialysis (LSD) with normal sodium dialysis (NSD). METHODS: Eight patients with initial high IDWG and seven with low IDWG completed hourly visual analogue ratings of thirst using a modified palmtop computer during the dialysis day and the interdialytic day. The dialysate [Na] was progressively reduced by up to 5 mmol/l over five treatments. Dialysis continued at the lowest attained [Na] for 2 weeks and the measurements were repeated. The dialysate [Na] then returned to baseline and the process was repeated. RESULTS: Baseline interdialytic day mean thirst was higher than the dialysis day mean for the high IDWG group (49.9+/-14.0 vs 36.2+/-16.6) and higher than the low weight gain group (49.9+/-14.0 vs 34.1+/-14.6). This trend persisted on LSD, but there was a pronounced increase in post-dialysis thirst scores for both groups (high IDWG: 46+/-13 vs 30+/-21; low IDWG: 48+/-24 vs 33+/-18). The high IDWG group demonstrated lower IDWG during LSD than NSD (2.23+/-0.98 vs 2.86+/-0.38 kg; P<0.05). CONCLUSIONS: Our results indicate that patients with high IDWG experience more intense feelings of thirst on the interdialytic day. LSD reduces their IDWG, but paradoxically increases thirst in the immediate post-dialysis period.     

Addition of sertraline to other therapies to reduce dialysis-associated hypotension

Sertraline has shown promise in the treatment of dialysis-associated hypotension (DAH) in a limited number of end-stage renal disease patients. We undertook a study to evaluate the effect of adding sertraline to other therapies for patients with documented DAH. We also measured the effect of sertraline on intradialytic haemodynamics. We used the ultrasound dilution technique (HD01 monitor) to measure cardiac output (CO), central blood volume (CBV) and peripheral vascular resistance (PVR) in these patients. The study was performed in two phases. Phase 1 was a control, while the second phase consisted of treatment with sertraline (50 mg/day). Cardiac output and central blood volume were measured 30 min following the initiation of dialysis and 30 min prior to the termination of dialysis. Blood pressure (BP) was monitored during haemodynamic measurements and throughout dialysis. Eighteen patients with documented DAH completed the study. Cardiac output, CBV and PVR were no different in the sertraline phase as compared with the control phase. The declines in systolic BP, diastolic BP and mean arterial pressures from pre-haemodialysis (HD) to lowest intradialytic and pre-HD to post-HD were not significantly different for the sertraline phase versus the control phase. In conclusion, it appears that sertraline has no additive effect on intradialytic haemodynamics to improve blood pressure in patients with DAH who are under therapy (with sodium modelling, cool dialysate and midodrine).     

Fluid balance during haemodialysis and haemofiltration: the effect of dialysate sodium and a variable ultrafiltration rate

One of the main causes of hypotension during extracorporeal renal replacement therapy is an insufficient substitution of the ultrafiltrated plasma water by tissue water. To investigate the fluid balance and its effects on hypotension in dialysed patients, the following variables were studied: intracellular fluid volume (IFV) and extracellular fluid volume (EFV), blood volume (BV) and blood pressure. IFV and EFV were measured by means of non-invasive electrical conductivity measurements using four electrodes round the leg. Fifteen haemofiltration (HF) and 15 haemodialysis (HD) patients were studied. The latter group was dialysed in three ways: (1) conventionally, i.e. with dialysate sodium of 138 mmol/l (HD) (2) with a variable dialysate sodium (first half: 138 mmol/l; second half: 146 mmol/l) (HDS), and (3) with the same variable dialysate sodium and an ultrafiltration profile (two-thirds was withdrawn during the first half of treatment, the remainder during the second half) (HDSU). Hypotension frequency was less during HDS, HDSU, and HF compared to HD. This was caused by a more stable blood volume due to a better refill. During HD a fluid shift occurred from the EC to the IC compartment. The use of a high sodium dialysate concentration led to a transcellular fluid shift in the opposite direction. This fluid shift increased the refill, thereby stabilising blood volume. HF gave a better refill than HDS and HDSU, probably due to a reduced urea clearance.     

Low-sodium haemodialysis without fluid removal improves blood pressure control in chronic haemodialysis patients

SUMMARY: Hypertension is an important and well‐established risk factor for both cardiovascular and cerebrovascular disease. Hypertension is much more common in patients on renal replacement therapy than in the general population. Up to 80% of patients on renal replacement therapy are hypertensive and about 50% of dialysis patients die from cardiovascular causes. Salt and water overload are major factors exacerbating hypertension in the dialysis population. This was a prospective crossover study of 10 patients examining the effect of haemodialysis for 2 weeks using usual (Na⁺ 138–140 mmol/L) sodium dialysate with a 2‐week period of low (reduced by an average of 5 mmol/L Na⁺ to 133 mmol/L on average) sodium dialysate on inter‐dialytic ambulatory blood pressure (ABPM) and trans‐thoracic bioimpedance (TTB). Ten patients, mean age 67 years, completed the study (two women and eight men). No patient became severely hyponatraemic during the study period. Mean 48 h inter‐dialytic blood pressure (BP) fell from 141/83 to 133/78 (P < 0.01). Mean arterial BP measured immediately prior to TTB fell from 92.8 mmHg to 87.5 mmHg (P < 0.01) during the low‐sodium haemodialysis period. Afterload (systemic vascular resistive index – SVRI) measured by TTB fell significantly during the low‐sodium haemodialysis period (SVRI on Na⁺‐140 = 3426 cf. Na⁺‐134 = 2281; P = 0.01). Dialysate sodium reduction without extra fluid removal had a beneficial effect on inter‐dialytic 48‐h blood pressure in chronic stable haemodialysis patients. Lowering dialysate sodium reduced the systemic vascular resistance index as measured by TTB. Reduction of dialysate sodium was well tolerated, although mild dizzines and cramps did occur. These data suggest that sodium overload and water overload may have independent effects on BP and that simple‐to‐achieve and modest changes in dialysate sodium could usefully augment the action of antihypertensives in dialysis patients.     

Effect of cool temperature dialysate on the quality and patients' perception of haemodialysis.

BACKGROUND: The effects of cool dialysate on the urea reduction ratio (URR) in high efficiency haemodialysis have not been completely studied. After reviewing the literature, it appeared that patients' perceptions of cool dialysis have not been studied. Since patients' perception have an impact on patient satisfaction, this motivated the authors to research this area of practice. METHODS: This study was designed to determine whether a high URR and haemodynamic stability could be achieved by using cool dialysate in two groups of patients. The first group of five patients were known to have hypotension episodes during dialysis, and the second group of five patients were documented as having stable blood pressure (BP) during and after dialysis, after excluding vascular access recirculation and any other problems. Each patient was dialysed for three sessions using cool dialysate (35 degrees C) followed by another three sessions using a standard dialysate temperature (36.5 degrees C). All other dialysis session parameters were maintained. RESULTS: The results show that the dialysate cooling resulted in an increased ultrafiltration in the low BP group (P = 0.05). Cool dialysis had neither an adverse nor a beneficial effect on urea removal in the two groups (P = NS). The mean arterial pressure post- and intra-dialysis was significantly higher in dialysis with cool dialysate in the low BP group (P < 0.01 and P < 0.007, respectively). The mean arterial pressure in the stable BP group remained unchanged when cool dialysate was used (P = NS). The intra-dialytic pulse rates in the low and stable BP groups were similar. A total of seven episodes of symptomatic hypotension were observed in the low BP group, but none in the stable BP group (P < 0.0001). Patients' perceptions about cool dialysate were measured by a questionnaire which showed that 80% of them felt more energetic after dialysis and requested to be always dialysed with cool dialysate. CONCLUSION: Cool dialysate improves tolerance for dialysis in hypotensive patients and helps increase ultrafiltration while maintaining haemodynamic stability during and after dialysis. Patients' perceptions were positive, as most of the selected sample felt more energetic and generally well during and after dialysis, and this had a positive impact on their activities of daily living.