Multifactorial Evaluation of Hernofiltration Therapy in Comparison with Conventional Hemodialysis

In order to ascertain if the potential benefits claimed for hemofiltration (HF) are supportable, chronic thrice-weekly HF therapy has been assessed in a group of nine uremic patients who had previously been stablized on conventional hemodialysis (HD) for a mean of 17.8 months at a frequency of 3 × 5 hours/week. Changes between the termination of HD (= initiation of HF) and the last three months were observed in multifactorial parameters.
No significant differences were observed in any parameter except the frequency of hypotensive episodes and the pretreatment levels of conventional waste metabolites.
The latter were higher on HF than HD and the frequency of hypotension, 2% in HF, was less than the 8% frequency observed in HD, despite much larger body weight reductions per HF treatment. Also, the effects of HF on hypertension and hyperlipidemia were not significantly better than observed on HD therapy. Our preliminary conclusions are that HF is superior to HD in both the ease and safety of fluid removal and there is virtual elimination of the disequilibrium syndrome. However, HF offers no other obvious advantages over conventional hemodialysis therapy.     

Hemodynamic Effects of Hemodialysis and Hemofiltration

The hemodynamic effects (n=8) of hemodialysis (HD) and hemofiltration (HF) were compared in the same group of dialyzed patients. The two procedures induced the same decrease in body weight, total blood volume, and blood pressure; however, hemodynamic alterations were different. Cardiac index and stroke index decreased markedly with HD and did not change significantly with HF, and peripheral resistance remained stable after HD and decreased significantly after HF.
These results suggest that the maintenance of a high cardiac output may account for the lack of acute hypotensive episodes Reported during HF. The reduction of blood pressure after HF is related to the decrease in total peripheral resistance. Thus, the arterial vasodilator effect induced by HF might explain the improvement of severe hypertension on long-term treatment with HF, as Reported previously.     

Evaluation of ß2-Microglobulin Removal with High-Performance Hemodiafiltration

Several lines of evidence suggest that beta 2-microglobulin (beta 2M) accumulation in long-term hemodialysis (HD) patients results in so-called dialysis-associated amyloidosis (DAA), which is clinically manifested by carpal tunnel syndrome, osteoarthropathy, and the other organ involvements. For the purpose of preventing the beta 2M accumulation, the efficiency of beta 2M removal during (HPM), hemofiltration (HF), HD, and charcoal hemodiafiltration (HDF) with high-performance membranes (HPM), hemofiltration (HF), HD, and charcoal hemoperfusion was evaluated. Among 27 patients treated with these methods, significant beta 2M removal was noted in HDF with HPM and HD with polyacrylonitril (PAN) membrane. However, treatment of HDF with HPM for more than 6 months caused no remarkable improvement in clinical symptoms of patients, and serum beta 2M levels decreased in only two out of 15 patients. These results imply that beta 2M might be most effectively removed by HDF with HPM and HD with PAN membrane, but further long-term studies will be necessary to conclude whether these procedures could become successful therapeutic regimen for DAA.     

Plasma atrial natriuretic factor (alpha ANF) during hemodialysis (HD) and hemofiltration (HF).

Plasma concentrations of immunoreactive alpha ANF were measured before, during, and after 3 hours of hemodialysis (HD) and hemofiltration (HF). In seven healthy subjects plasma alpha ANF concentrations were measured to serve as controls. Highly elevated pre-treatment alpha ANF levels were obtained in the HD group (286 +/- 52 pg/ml, mean +/- SE), and in the HF group (275 +/- 48 pg/ml) as compared with the controls (40 +/- 3 pg/ml). The effect of both HD and HF on the alpha ANF concentration was not significant after the first hour of treatment. However, a significant decrease was obtained after the second (HD = 244 +/- 49, HF = 140 +/- 17) and third hours (HD = 244 +/- 48, HF = 135 +/- 15) (p less than 0.05) in both treatments. A steeper decline in the alpha ANF concentration was notable during HF compared with HD. There was a significant difference (p less than 0.05) when both modalities were compared at the end of treatment. A correlation (r2 = 0.98, p less than 0.001) was noted between changes in the alpha ANF levels and the ultrafiltration (UF) volumes only during HF. Plasma alpha ANF concentrations at the filter outlet were lower than at the inlet in both groups. It is concluded that the plasma alpha ANF concentrations are highly elevated in chronic renal failure patients. Despite the decrease in these concentrations during HD and HF it did not reach the normal plasma level. Monitoring of plasma alpha ANF may be a useful indicator for the extracellular volume status during HD and HF treatments.     

Prostacyclin (epoprostenol) as the sole antithrombotic agent in postdilutional hemofiltration

Prostacyclin (PGI2), the most potent and short-lived antiplatelet agent known today, has been used successfully as an antithrombotic in hemodialysis (HD). However, its vasodilatory effect has been the source of blood pressure instability in acetate HD and has restricted its use to bicarbonate HD. The authors took advantage of the better cardiovascular stability obtained with hemofiltration (HF) to compare the effects of PGI2 versus heparin either with acetate or bicarbonate HF in 4 patients. Efficacy of PGI2 in preventing thrombosis of the extracorporeal circuit was demonstrated in all cases with a dose of 4 ng/kg/min. HF performances remained unaffected whatever antithrombotic agent was used. Platelet activation as shown by BTG and PF4 release was inhibited by the PGI2 infusion. Platelet proteins release was greater with acetate HF, suggesting that acetate may have a specific role in platelet activation. Although the use of PGI2 was straightforward, it is worth noting that PGI2 partially suppressed the cardiostability usually associated with acetate HF. We conclude that the efficacy of PGI2 was well maintained in spite of conditions of high platelet shear stress conditions, but also that PGI2 potentiated the vasodilatory effect of acetate and suppressed partially the cardiovascular benefits of HF.     

Comparative evaluation of bone aluminum content and bone histology in patients on chronic hemodialysis and hemofiltration

In order to compare hemofiltration (HF) and hemodialysis (HD) in connection with the risk of aluminum overload and renal osteodystrophy, double bone biopsies after double tetracycline labeling and a desferrioxamine test were performed in 12 patients on HF and 15 patients on HD. The aluminum concentration was low (less than 0.6 mumol/l) both in the dialysate and the substitution fluid. The duration of treatment (about 2 years) and the cumulative doses of Al(OH)3 and CaCO3 were comparable in the two groups. None of the patients was taking 1 alpha-OH-D. The aluminum balance during an HF run ranged from -22 to +1.8 mumol/l, the balance being positive only when the plasma aluminum was less than 0.5 mumol/l. Basal plasma aluminum and its increase induced by desferrioxamine were comparable in the two groups. Bone aluminum content was also comparable, but was about 10 times higher than in 7 nonuremic controls. Bone aluminum content and plasma aluminum increase after desferrioxamine were correlated to the Al(OH)3 cumulative dose. None of the patients had florid osteomalacia with increased osteoid thickness, and only 1 in each group had traces of stainable aluminum. The mineralization front was decreased in 8 of 12 HF and in 9 of 14 HD patients, so that no difference was observed between the means of the two groups. The predominant histological bone picture of the patients was osteitis fibrosa which was present in 10 of 12 HF and in 13 of 15 HD patients. Mean osteoclast count and active resorption surface were comparable in the two groups, but was increased (5-10 times the mean of the controls).(ABSTRACT TRUNCATED AT 250 WORDS)     

The recovery of the fluid balance after hemodialysis and hemofiltration.

Dialysis dysequilibrium syndrome is a frequent complication of renal replacement therapy and seems to be related to changes in fluid balance. From previous studies it is known that these changes are less pronounced during hemofiltration (HF), leading to a lower incidence of complaints compared to hemodialysis (HD). To assess the severity and duration of the dysequilibrium syndrome, intracellular (ICV) and extracellular fluid volumes (ECV) were measured during and after HD and HF by means of a non-invasive conductivity method. Blood volume changes were calculated from pre- and post-treatment erythrocyte counts. Seven HD and eight HF patients were studied. Ultrafiltration volume did not differ between both groups. Blood volume decrease was less during HF due to a significant decrease in ICV, the latter being in contrast to an ICV increment during HD. The significant decrease in ICV led to a less severe decrease in ECV (90 versus 85%). Overall, this resulted in a better vascular refill during HF. At the end of treatment ICV and ECV were not in equilibrium yet. During the recovery period ICV increased roughly 3% in the HF group. In the HD group some patients showed an increase while others showed a decrease in ICV. Overall, no change in ICV was noticed. During recovery ECV decreased further in both groups. The measured recovery period was significantly shorter after HF (245 +/- 68 min) than after HD (299 +/- 37), supporting the hypothesis that HF is a more physiological way of treatment compared to HD.     

Technical and Clinical Data on High-Performance Hemofiltration: Twelve Patients During One Year

In 12 chronic hemodialysis patients, postdilutional hemofiltration (HF) was substituted for conventional acetate hemodialysis (HD) (4-5 h/session with high-area capillary dialyzers). In HF, the purposes were to obtain (a) no increase in pre-HF uremia compared with pre-HD uremia (high ultrafiltrate volume), (b) an HF duration shorter than that of HD (mean ultrafiltrate rate greater than 120 ml/min), (c) a disposable cost of an HF session identical to that of an HD session (reuse of hemofilters and extemporaneous preparation of substitution fluid). One-year results were (a) an ultrafiltrate volume of 26.8 L/session and a pre-HF uremia of 35.4 mmol/L (pre-HD uremia 34.0 mmol/L), (b) a mean ultrafiltrate rate of 143 ml/min and a mean HF duration of 190 min (mean HD session duration 250 min), and (c) better clinical tolerance and vascular stability in HF than in HD (weight loss 3.5 kg in HF and 3.0 kg in HD). Reuse of filters and extemporaneous preparation of substitution fluid were not responsible for any pyrogen reaction or bacterial contamination. In conclusion, (a) compared with conventional HD, high-flux HF results included identical removal of small molecules, improvement in vascular stability, decrease in session duration, and identical disposable cost; (b) routine high-flux HF is workable in a dialysis unit; (c) vascular access is the most important limiting factor to high-flux HF. Today 30-40% of patients can be treated with this method.     

Chronic Hemofiltration

The experiences which have been compiled in more than 2400 hemofiltrations confirm that this method represents an alternative way of treating uremic patients. The main advantages of chronic hemofiltration are the comfort of the patient and the ease in handling excess overhydration without extending treatment time, which is less than 3 × 3 hours/week if adequate hemofilters are used. With regard to the improvement of such typical uremic complications as severe hypertension, hypertriglyceridemia or neuropathy, hemofiltration does not seem to be superior to hemodialysis. However, since most hemofiltration patients do not require phosphate binders and, additionally, remarkable amounts of parathyroid hormone are removed during one hemofiltration, it appears possible that hemofiltration might be an important therapeutic alternative for those renal patients who suffer from severe hyperphosphatemia and secondary hyperparathyroidism.     

Phenylacetate and benzoate clearance in a hyperammonemic infant on sequential hemodialysis and hemofiltration

An infant with a suspected inborn metabolism error was treated with a metabolic cocktail of intravenous sodium phenylacetate (NaPh) and sodium benzoate (NaBz) for hyperammonemia. Sequential hemodialysis (HD) then hemofiltration (HF) was performed due to hyperammonemia. Dialytic and convective clearance (K; ml/min) of ammonia, NaPh, and NaBz was measured. The K of ammonia was 57 and 37 for HD and HF, respectively. The K of NaBz was 37 and 12 for HD and HF, respectively. The K of NaPh was 38 and 14 ml/min for HD and HF, respectively. Despite high clearance of both NaPh and NaBz by HD and HF, the hyperammonemia was corrected.     

Thermal effects of different dialysis techniques and blood pump speeds: an in vitro study

Thermal effects have a pivotal impact on hemodynamic stability during dialysis procedures. In contrast to conventional dialysis techniques, there are no data in the literature regarding the thermal energy balance during on-line techniques. Secondly, little data exist on the effect of extracorporeal blood pump speed (EBPS) on thermal energy balance. In this study we assessed, first, relative differences in energy transfer rate (ETR) over the extracorporeal circuit during on-line hemo(dia)filtration (H(D)F) procedures and hemodialysis (HD) at different dialysate temperatures during an in vitro procedure using a blood temperature monitor (BTM). Secondly, we assessed the thermal effects of different blood pump speed (BPS) rates during the various treatment modalities. ETR was different among all treatment modalities (p < 0.05) studied, except for HD at 36.5 degrees C vs. pre-dilution hemofiltration (HF) and post-dilution HDF vs. HD at 37.5 degrees C. ETR had the most negative result, indicating the largest energy loss, during HD at 35.5 degrees C (-58.5.2 +/- 2.6 W), whereas it was almost comparable between pre-dilution HF (-30.7 +/- 4.1 W) and HD at 36.5 degrees C (-35.1.2 +/- 2.4 W). Post-dilution HDF (-17.7 +/- 1.2 W) resulted in an ETR comparable to that of HD at 37.5 degrees C (-15.0 +/- 3.9 W). ETR during post-dilution HF was -43.8 +/- 1.3 W. The thermal effect of the BPS was more pronounced during the procedures with the more negative ETR. In conclusion, on-line techniques and BPS have widely varying effects on ETR during dialysis, which should be considered when the hemodynamic effects among different treatment modalities are compared.     

Hemodiafiltration: A New Alternative To Hemofiltration And Conventional Hemodialysis*

A new dialysis method, termed hemodiafiltration, is proposed. The procedure consists of the combination of hemofiltration and conventional hemodialysis using high flux membranes with a transmembrane pressure (TMP) of 300–500 mmHg and a dialysate flow of 900 ml/min. Due to the combination of convective mass transfer and diffusion, the clearance values of both small and larger molecules are significantly higher than during hemofiltration or hemodialysis alone with the same membranes. The removal of excess water is better tolerated than during hemodialysis. With this new method, six patients have been successfully treated for six months (three times per week, three hours per treatment) without side effects. Thus, hemodiafiltration appears to be the method of choice to shorten dialysis time.     

血液透析联合血液灌流治疗尿毒症患者皮肤瘙痒的疗效

目的 观察血液透析联合血液灌流治疗尿毒症皮肤瘙痒患者的临床疗效.方法 选择我院72例维持性血液透析伴皮肤瘙痒患者,采用数字表法随机分为观察组(HD+ HP组)和对照组(HD组),每组各36例.对照组采用单纯血液透析(HD)治疗,每周3次,每次4小时;观察组在常规血液透析基础上加用2～3次/月的组合型人工肾治疗[血液透析(HD)联合血液灌流(HP)治疗].检测两组患者治疗前后β2-微球蛋白(β2-MG)、甲状旁腺激素(PTH),并观察两组患者皮肤瘙痒改善情况.结果 治疗2个月后观察组患者血β2-MG、PTH比对照组明显下降,差异有统计学意义(P＜0.05),皮肤瘙痒的程度明显减轻.结论 血液透析联合血液灌流可有效的清除血液中大分子毒素;有效缓解长期血液透析患者皮肤瘙痒症状,改善预后,提高了尿毒症患者生存质量.     

高通量血液透析与常规血液透析联合血液透析滤过的临床疗效比较

目的比较高通量血液透析（HFHD）与常规血液透析（HD）联合血液透析滤过（HDF）治疗尿毒症患者的有效性和安全性。方法选择维持性血液透析（MHD）患者55例,分为治疗组（高通量血液透析,3次／周）29例;对照组（低通量血液透析2次／周＋血液透析滤过1次／周）26例,随访6个月,进入试验前1周内（基线期）及开始治疗后3、6个月测定周中透析前血常规、肝肾功能、电解质、全段甲状旁腺激素（iPTH）、132微球蛋白（132一MG）、C反应蛋白（CRP）,记录每次透析透前、透后血压。结果2组血常规、白蛋白、CRP、电解质、VI＇H、血脂等指标各时期的组内及组间均无统计学差异（P〉（）．05）。各时期每次透析前、后收缩压（SE｜P）、舒张压（I）J妒）的组间比较无统计学差异（P〉O．05）。治疗组自开始治疗后第1月起至第6月透析前SBP较基线期显著下降（P〈f）．05）。2组各个时期血清胆一MG及血磷比较无显著差异,但治疗组第6个月的血磷值显著低于基线期（P〈0．01）。结论两种透析方式长期疗效可能是相当的,HFHD组血压的控制及血磷的清除更好,可能更有临床推广的潜力。     

血液灌流联合血液透析对血地高辛清除率的影响

目的观察血液灌流联合血液透析（HP＋HD）、血液透析（HD）对维持性血液透析（MHD）患者血地高辛清除率的影响。方法选择30例MHD患者每周行HP＋HD治疗1次、HD治疗2次,每次治疗4h。采用自身前后对照研究,每例患者分别观察HP＋HD治疗1次、HD治疗1次,总计60例次,分为HD＋HP组30例次和HD组30例次。观察2组透析前后血地高辛浓度、尿素氮（BUN）,比较2组治疗前后血地高辛浓度、地高辛清除率、尿素下降率（URR）和单室模型尿素清除指数（spKt／V）。结果2组治疗前血地高辛浓度、URR和spKt／V比较无统计学差异（P〉O．05）。2组治疗后血地高辛浓度均显著低于治疗前（P〈0．01）,但HD＋HP组血地高辛清除率明显高于HD组（P〈0．01）。结论两种透析方式对血液中地高辛均有清除作用,HP＋HD治疗对地高辛清除率较HD治疗效果高。     

Hemofiltration as a Treatment for “Dialysis-Resistant” Hypertension and Hypotensive Hyperhydration

Normalization of blood pressure cannot be achieved in about 5% of patients with chronic renal insufficiency by fluid and sodium extraction on dialysis. An accompanying high plasma renin activity has, until now, been an indication for bilateral nephrectomy. In a group of 8 patients, treated since 1974 by hemofiltration, 3 had been originally considered for bilateral nephrectomy. However, through this treatment their blood pressure was normalized. The extraction of large quantities of fluid was tolerated by the patients; they did not have side effects such as muscle cramps or vascular collapse. Large quantities of fluid can also be removed by hemofiltration from hyperhydrated normotensive patients without hypotensive reactions. The present results show that the response of blood pressure to the extraction of a definite amount of fluid by hemofiltration is dependent upon the starting blood pressure: the higher the blood pressure value at the start of hemofiltration, the greater is the effect of dehydration on blood pressure.

Observations on the pathogenesis of hypertension in patients with terminal renal insufficiency leave no doubt as to the importance of salt and water retention. It has been found that approximately 95% of hypertension in dialysis patients is controlled by hemodialysis. The remaining, so-called “dialysis-resistant” forms are, as a rule, controlled after bilateral nephrectomy.

Investigations of blood pressure response during dialysis against high sodium concentrations have shown that isotonic dehydration is the critical factor for lowering blood pressure, and not the rapid decrease in exchangeable sodium (3, 4). It is therefore to be expected that hypertension in terminal renal Insufficiency can be more effectively controlled by hemofiltration, a dialysis form with isotonic fluid reduction of the extracellular space, than by other forms of dialysis treatment. The object of our investigation was to determine how well dialysis resistant hypertension could be regulated during both a single dialysis, and over a period of long-term treatment.     

Cardiovascular surgery in patients on chronic dialysis: effect of intraoperative hemodialysis

To evaluate the operative result and the perioperative management of dialysis patients undergoing elective cardiac surgery, we retrospectively reviewed consecutive adult patients with chronic renal failure dependent on maintenance dialysis. Between April 1994 and March 2002, 20 patients who underwent cardiopulmonary bypass (CPB) procedures were studied. Fourteen patients underwent isolated coronary artery bypass grafting, four valve replacements and two combined procedures. Our strategy for the chronic dialysis patients was as follows: dialysis the day before the operation, intraoperative hemodialysis (HD) during CPB, and no dialysis or hemofiltration (HF) on the operative day. Intraoperative HD produces the optimal fluid and electrolyte balance at the end of the operation. The mean interval between the end of surgery and the commencement of HD was 31.2+/-12.5 h. No patients required any hemocatharsis such as HF or HD on the day of operation. The overall operative mortality was 5.0%. There were six late deaths (30.0%). Overall, including the operative and non-cardiac death, actuarial survival rate was 85.0% at 1 year, 70.0% at 5 years, and 65.0% at 6 years. Intraoperative HD has an advantage in the postoperative period; it avoids the hemodynamic instability and the risk of heparin-associated bleeding associated with the use of HD.     

Modulation of the immune response to HBV vaccination by hemodialysis membranes

Introduction  

Seroconversion response to Hepatitis B virus (HBV) vaccination is limited in uremic patients because of impaired humoral and cellular immune activity. Recent studies show that high-flux (HF) hemodialysis (HD) membranes can improve T cell functions and decrease the proinflammatory cytokine activation more effectively than low-flux (LF) membranes. In regard to HF membranes may have immune modulator effects; we compared the antibody responses to hepatitis B vaccination between HF HD and LF HD membranes.     

The rate of increase in hematocrit, humoral vasoactive substances and blood pressure changes in hemodialysis patients treated with recombinant human erythropoietin or blood transfusion.

The role of the rate of increase in hematocrit (Hct) and changes in vasoactive substances as a cause of hypertension induced by the administration of recombinant erythropoietin (r-EPO) were examined in 20 stable hemodialysis (HD) patients. Measurements were made twice at the start of treatment and when the Hct reached 30%. Patients were divided into 2 groups: Group I: 14 patients received r-EPO, 3000 units intravenously three times a week. Group II: 6 patients, needing repeated blood transfusion, were given 2 to 4 units of washed red blood cells during a HD session. The Hct increased by 0.65%/week in Group I and by 6.7%/2 days in Group II. An elevation in blood pressure was not seen in any patient. There was no difference in the levels of renin, angiotensin II, epinephrine, norepinephrine, dopamine, atrial natiuretic peptide (ANP), BUN, creatinine, cardiac thoracic ratio and body weight in any of the groups. In conclusion, elevation of the Hct in HD patients whatever the rate of increase within the 30% Hct range, does not cause an increase in blood pressure. In addition, the levels of vasoactive substances do not change in partially corrected anemic HD patients. As a result blood pressure control can be helped by aiming at the lower target Hct level of around 30%.