Hemodiafiltration

Effect of online hemodiafiltration on quality of life, fatigue and recovery time: a systematic review and meta-analysis

The present systematic review and meta-analysis aims to compare the effect of bicarbonate hemodialysis and HDF on quality of life (QoL), fatigue, and time to recovery in end-stage renal disease (ESRD) patients. Searches were run on January 2024 and updated on 3 March 2024 in the following databases: Ovid MEDLINE (1985 to present); Ovid EMBASE (1985 to present); Cochrane Library (Wiley); PubMed (1985 to present). Ten articles were fully assessed for eligibility and included in the investigation. Compared to HD, online HDF had a pooled MD of the mental component score (MCS) of the SF-36 of 0.98 (95% CI - 0.92, 2.87; P = 0.31). and of the physical component score (PCS) of 0.08 (95% CI - 1.32, 1.48; P = 0.91). No significant heterogeneity was observed (Chi2 = 4.85; I2 = 38%; P = 0.18 and Chi2 = 3.85; I2 = 22%; P = 0.28, respectively). Studies that compared the QoL assessed through the Kidney Disease Questionnaire or KDQOL-SF and show that HDF does not improve QoL when compared with HD, in most studies. In five out of seven studies, HDF was not significantly more effective than HD in improving fatigue. The length of the recovery time resulted in similar in patients receiving HDF and HD in all studies included in the present review. HDF is not more effective than HD in improving QoL and fatigue and in reducing the length of time of recovery after dialysis.

Development of a new miniaturized system for ultrafiltration

Acute decompensated heart failure and fluid overload are the most common causes of hospitalization in heart failure patients, and often, they contribute to disease progression. Initial treatment encompasses intravenous diuretics although there might be a percentual of patients refractory to this pharmacological approach. New technologies have been developed to perform extracorporeal ultrafiltration in fluid overloaded patients. Current equipment allows to perform ultrafiltration in most hospital and acute care settings. Extracorporeal ultrafiltration is then prescribed and conducted by specialized teams, and fluid removal is planned to restore a status of hydration close to normal. Recent clinical trials and European and North American practice guidelines suggest that ultrafiltration is indicated for patients with refractory congestion not responding to medical therapy. Close interaction between nephrologists and cardiologists may be the key to a collaborative therapeutic effort in heart failure patients. Further studies are today suggesting that wearable technologies might become available soon to treat patients in ambulatory and de-hospitalized settings. These new technologies may help to cope with the increasing demand for the care of chronic heart failure patients. Herein, we provide a state-of-the-art review on extracorporeal ultrafiltration and describe the steps in the development of a new miniaturized system for ultrafiltration, called AD1 (Artificial Diuresis).

The rationale and clinical potential of on-line hemodiafiltration as renal replacement therapy

On-line hemodiafiltration (ol-HDF) was developed in the 1980s in response to the unmet medical needs observed with conventional low- and high-flux hemodialysis. Firstly, the limited overall efficacy of conventional HD treatment programs as compared to native kidney function has been consistently documented over the broad MW spectrum of uremic toxins as well as fluid volume and hemodynamic control. Secondly, the unphysiological profile of intermittent treatment leading to repetitive dialysis-induced hemodynamic stress is now a well-recognized component of cardiovascular disease and end organ damage. Thirdly, the bioincompatibility of patient-dialysis system leading to dialysis-induced biological reactions also identified as contributing to dialytic morbidity and mortality. To overcome these limitations and pitfalls, alternative convective-based therapies (hemofiltration and hemodiafiltration), using higher hemoincompatible membranes and ultrapure dialysis fluid, were proposed as a solution to enhance and enlarge MW spectrum of uremic compounds cleared and to reduce dialysis-patient biological interactions. In this context, online HDF appeared soon as the best viable and efficient renal replacement modality to cover these needs. Clinical development and implementation of ol-HDF showed also that dialytic convective dose matters with a threshold point (23 L/1.73 m² in postdilution mode) to observe clinical benefits and outcomes improvements.

Hemofiltration in septic ARDS. The artificial kidney as an artificial endocrine lung

Twenty-four patients with high microvascular permeability pulmonary edema were initially treated by means of conventional supportive therapy for 1-12 days. Continued deterioration was treated by predilutional hemofiltration and induced a dramatic improvement in 22/24 patients. Survival was 92%. Sieving coefficients for autacoids and middle molecular weight vasoactive peptides involved in the development of high microvascular permeability pulmonary edema were higher than 0.88 indicating that clearing from blood of these peptides during one pass through the hemofilter is similar to that obtained during one pass through the pulmonary normal microvasculature. Hemofiltration seems to be a significant breakthrough in the treatment of ARDS secondary to severe sepsis.

Multifactorial evaluation of hemofiltration 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 stabilized on conventional hemodialysis (HD) for a mean of 17.8 months at a frequency of 3 x 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.

Superiority of hemofiltration to hemodialysis for treatment of chronic renal failure: comparative studies between hemofiltration and hemodialysis on dialysis disequilibrium syndrome

A significantly lower incidence of DDS, hypotension, and impending shock was found during and after hemofiltration as compared with conventional hemodialysis. Hemofiltration, in contrast to hemodialysis, showed less decrease of circulating plasma volume, mild change in plasma osmolality without red cell swelling, better compensation of acidosis despite less uptake of acetate, more stable PCO2 during the procedure, less paradoxical acidosis in cerebrospinal fluid, and a lower urea concentration gradient between cerebrospinal fluid and plasma. These phenomena might be explained by better mass transfer between compartments bithin the body during hemofiltration. Mass transfer from the intracellular as well as the extracellular space to circulating plasma occurred more rapidly and smoothly during HF than during HD. HF is preferable to HD in patients with severe cardiovascular complications such as hypertension, as well as hypotension and cardiac failure, and in those subject to DDS during HD. Accordingly, hemofiltration therapy promises patients more comfortable and more stable treatment of chronic uremia.

Hemodiafiltration using readily available equipment

Hemodiafiltration as a blood purification method is a combination of hemodialysis and hemofiltration. With this procedure low molecular substances are predominantly cleared by diffusion while middle molecules are cleared mainly by convection. This report shows how hemodiafiltration can be done using readily available equipment: a regular dialysis machine, an "open membrane" and the COTRAL device. Treatment could be reduced to about 2/3 of dialysis time. With a TMP of 600 mmHg a filtration rate of 60 - 70 ml/min at a blood flow of 200 ml/min and a dialysate flow rate of 500 ml/min the following. Clearance values were obtained: Urea 140 ml/min, creatinine 128 ml/min and inulin 76 ml/min. Increasing the blood flow to 300 ml/min and dialysate flow to 1000 ml/min clearances were: urea 192 ml/min, creatinine 161 ml/min and inulin 91 ml/min. During a 3.5 hour treatment period max. 92.4 urea and 6.3 g creatinine and 36 mg B2 microglobulin were extracted. In our opinion this in our hand advantageous procedure deserves further study.

Hemodynamics during hemodialysis, sequential ultrafiltration and hemofiltration

Circulatory parameters were determined by cardiac catheterization in patients on maintenance hemodialysis. They were studied in three groups during conventional hemodialysis, sequential ultrafiltration and hemofiltration. All three groups revealed significant reduction of cardiac output, stroke volume, pulmonary artery pressure and plasma volume. In the hemodialysis group hemodynamic parameters were unstable; specifically, hypotension, increased heart rate, and only minimal increase of peripheral resistance were observed. The other two groups showed only minor changes in circulatory parameters despite high ultrafiltration rates. Blood pressure and heart rate remained stable. On the other hand, peripheral vascular resistance increased remarkably. There is compelling evidence that during hemofiltration and sequential ultrafiltration, the patient's ability for vasoconstrictive counterregulation is better maintained than during conventional hemodialysis.

Hemodynamic studies, acid-base status and osmolality in different hemodialysis procedures

Three patients on maintenance dialysis were each treated with three different procedures: A) twenty-liter recirculation dialysis with bicarbonate buffering, B) recirculation-adsorption dialysis and C) single-pass dialysis. Hemodynamic parameters were measured invasively and procedures A, B and C were compared for each patient. In this intraindividual comparative study, the authors attempted to establish a relationship between the varying hemodynamic parameters and the changes in osmolality and acid-base status. There were indications of some causal relationship to circulatory stability: in A and B, there were peripheral resistance increases of 24.5% and 38.4%, respectively, with stable circulation; in C, there was a 6.1% increase and unstable circulation. Additionally, the influence of acidosis is shown in B, with disproportionately strong reductions of cardiac output (21.9%) and pulmonary artery pressure (44.9%); In spite of a decrease of osmolality (A: 15.6 mOsm/L), stable circulation could be achieved if the peripheral resistance was substantially increased and acid-base status was equalized.

Inadequate clearance of small molecular weight solutes during hemofiltration using Cuprophan membranes

In a study of four patients treated with one hour of hemofiltration using Cuprophan membranes, followed by three hours of dialysis, it was found that patients will have reduced clearances of small molecular weight solutes. This may be prevented by increasing blood flow rates to compensate for the time spent in hemofiltration. Cuprophan membranes do not clear middle molecular weight solutes as well as other membranes, but fluid removal is comparable to that reported by other investigators using more porous membranes.

Pragmatic realities in uremia therapy

The present status and future prospects of uremia therapy in the United States are reviewed. Approximately 3500 renal transplants were done in 1976 as compared to 3700 in 1975. Functional two-year survival of grafts has not changed recently (40 to 45 per cent for cadaver donors; 70 to 75 per cent for siblings), but patient survival with cadaver grafts continues to improve (now 65 per cent at two years). Patients on hemodialysis in facilities are increasing rapidly. Only 13 per cent are on home dialysis, as compared with nearly 40 per cent five years ago. Home patients do at least as well as those in centers (80 per cent two-year survival) and cost 40 per cent less. Physician bias probably explains the trend to center dialysis, but pending legislation may provide new incentives for home treatment. Prospects for technical advances are good, but a greater federal investment in research and development is needed. Dollars saved on the center dialysis could be used for this purpose.

Ultrafiltration followed by haemodialysis. A longterm trial and acute studies

Separate ultrafiltration followed by haemodialysis (U.F.-H.D.) using Gambro Major or Cordis-Dow hollow-fiber dialyzers were evaluated in 10 dialysis patients over a mean period of 4 1/2 months and 455 U.F.-H.D. procedures. Fluid control was facilitated in oedematous patients but the number of hypotensive episodes during the combined procedure requiring intravenous 5% saline did not significantly decrease. No significant improvement in hypertension was noted. Ultrafiltration (U.F.) alone for acutely water overloaded, azotaemic patients proved very useful. Two to five liters of oedema fluid could be removed asymptomatically in one to three hours using transmembrane pressures of 250 to 500 mmHg and U.F. rates of 10 to 42 ml/min. Two patients became acutely and symptomatically hypotensive. One was an insulin dependent diabetic in whom 3800 ml were removed in 75 minutes and the other a hypertensive patient undergoing treatment with Minoxidil and propranolol.

Critical appraisal of haemofiltration and ultra-filtration. The development of ultra-short dialysis: preliminary results

The clinical experience obtained with 2 hours every other day recirculation dialysis, using 20-40 liters of dialysate, without sorbents, and standard cuprophane dialyzers of 1.0-1.5 sq.mt. is reported. So far, over 350 treatments in 8 patients have been performed. After 2 hours of treatment the removal of urea, creatinine, phosphate and uric acid, is similar to that obtained by 4-6 hours of haemofiltration. The alkalinazation of the patient through direct venous infusion of bicarbonate, makes predialysis acid-base significantly better than in standard haemodialysis and haemofiltration. Asymptomatic correction of severe fluid overload is easily obtained like in isolated ultrafiltration. The role of osmolality and vasopressors are discussed. A dry weight below the value obtained by previous dialysis treatment is achieved, and volume dependent hypertensions as in haemofiltration are corrected after 2-8 weeks. As an additional advantage, this method offers a highly semplified technical approach and a further reduction of the dialysis time.