Effect of Hybrid Blood Purification Treatment on Secondary Hyperparathyroidism for Maintenance Hemodialysis Patients

OBJECTIVE

This study aims to investigate the effects of hybrid blood purification treatment on secondary hyperparathyroidism for maintenance hemodialysis (HD) patients.

METHODS

A total of 40 patients were randomly divided into 2 groups: HD combined with hemoperfusion (HD + HP) group (n = 20) and HD group (n = 20). Changes in intact parathyroid hormone (iPTH) in these 2 groups were compared before and after treatment, and iPTH levels in the HD + HP group were monitored before and after treatment.

RESULTS

iPTH, β2 microglobulin (β2-MG), and cystatin C (CysC) levels were significantly lower in the HD + HP group than in the HD group (p < 0.05), iPTH levels were significantly higher than at the first day after treatment (p < 0.05), and iPTH level was significantly higher (p < 0.05).

CONCLUSION

The clearance effects of HD + HP on iPTH, β2-MG, and CysC are better than HD alone. Treatment with HD + HP every 2 weeks is recommended for maintenance HD patients.

Detoxifying capacity and kinetics of the molecular adsorbent recycling system. Contribution of the different inbuilt filters

The molecular adsorbent recycling system (MARS) represents a cell-free, extracorporeal, liver assistance method for the removal of both albumin-bound and water-soluble endogenous toxins. The aim of the present study was to evaluate the short- and long-term removal capacity and selectivity of the different inbuilt dialysers and adsorption columns (uncoated charcoal, anion exchanger resin). Levels of endogenous toxins and parameters of hepatic synthesis and necrosis were therefore monitored before, during and after the MARS treatment phase in 10 patients. Moreover, blood and dialysate clearances of urea, creatinine, bilirubin and bile acids were determined during a single treatment. The significant increasing time course of total bilirubin blood levels before the start of the treatment could be stopped and reversed in a significant decreasing time course. The removal rates of urea nitrogen, bilirubin and bile acids during a single treatment amounted to 55.5 +/- 4.0, 28.3 +/- 3.9, and 55.4 +/- 4.0% (mean +/- SEM), respectively. The efficacy of removal of albumin-bound toxins sharply declined early after initiation of the treatment to become negligible after 6 h. In conclusion, both albumin-bound and water-soluble toxins are adequately removed by the MARS. Our data suggest that the rate and efficacy of removal of albumin-bound toxins are related to both the strength of the albumin binding and the saturation of the adsorption columns.

Perfusion treatment algorithm: methods of improving the quality of perfusion

The pathophysiological consequence associated with cardiopulmonary bypass (CPB) has generated a movement away from this technology in the treatment of heart disease. The negative outcomes are multifactorial in origin and may be associated both with the conduct of CPB and the instrumentation of extracorporeal flow. The purpose of this study was twofold. First, to develop a bedside patient risk assessment to aid in the development of a perfusion care plan. Second, to identify the controllable variables used during CPB that contribute to overall morbidity. Controllable perfusion-related variables that were positively linked to improved patient outcomes were identified from randomized, peer-reviewed human studies. Such variables as hematocrit, mean arterial pressure, thermic perfusion, blood lactate, colloid osmotic pressure, pulsatile perfusion, acid base homeostasis, oxygenation, and coated circuitry were included. Patient risk assessment was developed using the Society of Thoracic Surgeon database, where 61 variables affecting postoperative morbidity were identified. These variables were used to develop a bedside tool, Mortality Assessment Perfusion Score (MAPS), to guide the perfusion patient care plan. The MAPS generates a specific value that may predict patient morbidity and mortality based on past mortalities. In conclusion, the improvement in patient outcome may be associated with both the change in conduct of CPB and the quantitative assessment of patient risk stratification and a patient treatment algorithm.

The next step from high-flux dialysis: application of sorbent technology

The current foci of renal replacement therapy with dialysis are middle molecular weight toxins, consisting of small proteins, polypeptides and products of glycosylation and lipoxygenation. Conventional high-flux dialysis is not efficient at removing these molecules, explaining the increased interest in using sorbents to supplement dialysis techniques. Prototype biocompatible sorbents have been developed and investigated for middle molecule removal; these have been shown, in man, to remove beta(2)-microglobulin, angiogenin, leptin, cytokines and other molecules, without reducing platelets and leukocytes. Extensive clinical studies are underway to demonstrate the clinical utility and safety of adding routinely a sorbent hemoperfusion device to hemodialysis.

Massive triiodothyronine intoxication: efficacy of hemoperfusion?

A case of massive accidental triiodothyronine intoxication (1000-fold the usual therapeutic dose, for 8 days) is reported with important disturbances of cardiovascular and central nervous systems that required intensive care support. Serum free triiodothyronine levels were 4789 pmol L(-1) on admittance (normal values, 3.5-6.5 pmol x L(-1)). In the absence of a specific treatment, hemoperfusions were performed but failed to accelerate significantly the decay of blood levels of free triiodothyronine (apparent half-life 25.9 hours; 95% confidence interval: 19.8-37.4 hours). The patient, a young woman, made a satisfactory recovery, in spite of important clinical complications.

Extracorporeal fibrinogen adsorption--efficacy, selectivity and safety in healthy subjects and patients with foot ulcers

The elimination of fibrinogen from plasma improves plasma viscosity and whole blood viscosity. For extracorporeal adsorption of fibrinogen the pentapeptide gly-pro-arg-pro-lys was coupled to sepharose CL-4B. Columns containing 100 ml of coupled sepharose CL-4B were used to eliminate fibrinogen from the plasma of 8 healthy male subjects (mean age 27.4 +/- 4.3 years, height 180.9 +/- 8.3 cm, weight 85.1 +/- 13.6 kg). Four treatments were performed in each proband (days 1, 2, 4 and 7). Plasma fibrinogen concentration was lowered from 221.1 +/- 39.0 to 123.5 +/- 21.7 mg/dl (2275 +/- 477 ml plasma treated) by the first treatment, from 172.8 +/- 42.3 to 105.6 +/- 16.5 mg/dl (1609 +/- 761 ml) by the second, from 140.5 +/- 13.8 to 98.8 +/- 8.6 mg/dl (1224 +/- 118 ml) by the third and from 160.2 +/- 23.6 to 106.4 +/- 9.7 mg/dl (1513 +/- 521) by the fourth. Plasma viscosity was improved from 1.40 +/- 0.18 mPa s before the first treatment to 1.23 +/- 0.06 mPa s after fourth treatment, whole blood viscosity from 4.49 +/- 0.36 mPa s to 3.83 +/- 0.27 mPa s (P < 0.01). No clinical side effects and no clinically relevant change of laboratory parameters including in vitro tests on thrombocyte function were observed. Seven men and three women (48-75 years old, 9 patients suffered from diabetes mellitus, one patient from peripheral arterial occlusive disease, 5 patients were on regular hemodialysis) were treated by fibrinogen adsorption. Each column contained 135 ml of coupled sepharose CL-4B. Treatments were scheduled on day 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25 and 28. 144 treatments with fibrinogen adsorption were performed. No clinical side effects due to the fibrinogen-adsorption procedure were observed. In these 10 patients the fibrinogen concentration before the first treatment was 473.7 +/- 183.7 mg/dl. In the first treatment session it was lowered to 241.4 +/- 125.8 mg/dl by treating 4270 +/- 1180 ml of plasma. In the following 134 treatments the pre-treatment concentration of fibrinogen was 262.6 +/- 83.4 mg/dl, the post-treatment concentration was 120.6 +/- 37.2 mg/dl. The mean volume of plasma treated was 3737 +/- 1643 ml, the mean duration of a treatment session (except the first treatment) was 143.7 +/- 63.1 min. In 7 patients a mean post-treatment fibrinogen concentration of < or = 123 mg/dl was obtained, in the other patients 133, 177 and 184 mg/dl. Yet, the decrease of fibrinogen concentration was also pronounced in these 3 patients: -82%, -67%, and -73%, respectively. Accelerated wound healing was observed in 9 of the 10 patients. In conclusion, affinity chromatography using the pentapeptide gly-pro-arg-pro-lys is an effective, selective and safe procedure to lower fibrinogen concentration in plasma thereby improving blood viscosity. It could be a therapeutic option in severe blood vessel disease where drug therapy is not sufficient and invasive procedures like bypass or angioplasty cannot be applied.

Status of pediatric perfusion education: 2000 survey

In recent years, studies have raised questions about pediatric perfusion training, minimum proficiency requirements, and specialization. To understand these questions better, a survey was undertaken to investigate the status of pediatric/neonatal perfusion training in the United States. Three groups were surveyed: program directors (PD), recent graduates of perfusion programs (RG), and pediatric cardiac anesthesiologists (PCA). Program directors and recent graduates were queried about didactic curriculum and clinical experiences. All three groups were asked core questions regarding minimum proficiency, specialization, and need for a postgraduate style program. Didactically, 65% of program directors believed that perfusion programs provided a solid introductory knowledge base in infant perfusion. Clinically, students performed an average of 124 +/- 42.5 adult and 17 +/- 12.9 pediatric cases during their education. Program directors cited numerous limitations to clinical pediatric education, including access to pediatric cases and allocation of resources. The PD (69%) and RG (96%) both believed graduates were less prepared to perform infant/pediatric cardio-pulmonary bypass (CPB) at graduation as compared to adult CPB. The opinions of all three groups were divided when asked whether the essentials and guidelines requirement for minimum pediatric caseload is too low (yes response: PD 52%, RG 73%, PCA 47%). The PD and RG were against pediatric subspecialization/certification (87%, 57% respectively); whereas, the PCA were unanimously in favor (100%) of pediatric subspecialization/certification for perfusionist. All three groups felt a postgraduate-style program in infant perfusion would benefit the community (78%, 82%, 100%). Finally, 64% of RG said that, if available, they would have considered entering a training program in pediatric/neonatal perfusion after graduation. Our results indicate that there are still limitations to pediatric perfusion education. A postgraduate-style program in infant perfusion is one possible solution to this problem.

Performance characteristics of combined haemodialysis/haemoperfusion system for removal of blood toxins

The application of high clearance haemodialysis (HD) for removal of small molecules of waste metabolites, has been practised for many years. Haemoperfusion (HP) is capable of effective removal of middle and protein-bound molecules. The combined HD/HP system is thought to give a more effective treatment for patients of renal failure or drug intoxication. This paper discusses the performance characteristics of removal of toxic substances (e.g. paraquat and creatinine), using the combined HD/HP recycled system in two different arrangements (HD-HP and HP-HD). The results demonstrate that for most favourable adsorbing solutes, the HD-HP arrangement gives higher performance whereas, HP-HD arrangement is more suitable and gives more effective detoxication characteristics for unfavourable adsorbing solutes.

Long-term clinical evaluation of an adsorbent column (BM-01) of direct hemoperfusion type for beta 2-microglobulin on the treatment of dialysis-related amyloidosis

The clinical efficacy and safety of a beta 2-microglobulin (beta 2M) adsorbent column, BM-01, on the treatment of dialysis-related amyloidosis were investigated in 7 hemodialysis patients for more than 6 months. The percent reduction of serum beta 2M was more than 60-70%, and the level at the end of each session was less than 10 mg/L in almost all patients. The amount of beta 2M removed was calculated as more than 200-300 mg/session. The results demonstrated that BM-01 performed very well for removing beta 2M, was capable of maintaining less than 25 mg/L of time average concentration (TAC) for beta 2M, and improved the clinical symptoms. Clinically severe side effects were not observed. We recommend that BM-01 should undergo further evaluation for its usefulness in the long-term treatment of dialysis-related amyloidosis, though treatment with the column may not be successful in preventing the onset of the disease.

Experience with hemoperfusion for organophosphate poisoning

OBJECTIVE

To evaluate the usefulness of extracorporeal clearance techniques in the treatment of organophosphate poisoning, particularly hemoperfusion.

DESIGN

Retrospective study.

SETTING

An ICU of a general hospital.

PATIENTS

Ten patients with organophosphate poisoning initially received classic treatment with gastric lavage and washing of the whole skin surface, as well as the administration of cathartics, activated charcoal, atropine, and obidoxime or pralidoxime. All patients underwent one to three hemoperfusions.

MEASUREMENTS AND MAIN RESULTS

Plasma insecticide concentrations and cholinesterase activity were determined daily. Two to three biopsies of fat tissue were carried out at 1- to 2-wk intervals. The amount of the insecticide removed during hemoperfusions was also determined. Five patients presented with a prolonged nicotinic syndrome. Two of these patients showed sequelae of delayed neurotoxicity. Another two of the five patients died and the remaining patient recovered without sequelae. In none of the patients could > 0.1% of the total absorbed poison be removed by hemoperfusion. No changes in symptoms were observed after these procedures. Fat tissue concentrations of the insecticide were 20 to 50 times higher than the concentrations in plasma. Atropine decreased the intestinal transit time, and 10 days after poisoning, a powerful cathartic treatment indicated the persistence of gut content, which probably caused prolonged absorption of the toxin.

CONCLUSIONS

Extracorporeal cleansing mechanisms did not remove any clinically important amount of insecticide from our patients due to the high lipid solubility of these agents and no changes in symptoms were observed after these methods. The use of atropine decreases bowel peristalsis. Early use of powerful cathartics could avoid protracted absorption of the poison stored in the gut, although the potential benefits of this therapy require confirmation by the performance of prospective, controlled investigations.

[New apparatus for artificial liver support: PAT resin--removal of protein-bound substances and its effect on hepatic failure in animals]

Hemoperfusion using several materials such as activated charcoal is often performed to treat the patients with hepatic failure. Polyamine triglycidylisocyanulate (PAT) resin is a newly developed artificial liver support material to adsorb protein-bound substances. In this study, the effect of PAT resin on the removal of these toxic protein-bound substances was examined and following results were obtained. PAT resin adsorbed protein-bound substances selectively in vitro. Its adsorbability was superior to those of the other conventional adsorbents such as cellulose-coated charcoal, XAD-4 and XAD-7. Serum bilirubin levels were decreased by 44% in jaundiced dogs and 45% in jaundiced rabbits after 120 minutes hemoperfusion with PAT resin. Leucocyte and thrombocyte count also fell during hemoperfusion. The fall of these blood cell counts, however, was recovered by prostaglandin D2. The survival time of dogs with ischemic hepatic failure was prolonged by hemoperfusion using PAT resin. The mean survival times were 17.6 hrs in the PAT perfusion group and 10.9 hrs in the control group. The difference of survival time between these two groups was statistically significant. (p less than 0.05). These results in animals suggest that PAT resin will be clinically useful in the therapy of hepatic failure or hyperbilirubinemia.

In vivo evaluation of a composite sorbent for the treatment of paraquat intoxication by hemoperfusion

In vivo evaluation of a new hemoperfusion (HP) device for Paraquat detoxification is reported. The key element of the extracorporeal system is a column packed with newly developed composite sorbent beads containing Fullers' Earth (FE) entrapped in crosslinked Agarose. The proposed HP system exhibits very good biocompatibility characteristics when conventional heparinization is supplemented by infusing 0.02 ml per min acid-citrate dextrose (ACD) solution per ml. perfused blood at the inlet to the HP column. No complications or abnormalities were detected in animals which were hemoperfused with the system described. It is suggested that the new device is effective and safe for clinical application.

[Metabolism of carbromal during detoxication with combined hemoperfusion and hemodialysis (author's transl)]

Combined charcoal hemoperfusion and hemodialysis was performed on three occasions in two patients with severe carbromal intoxication. The concentration of carbromal, its organic metabolites and of bromide was determined in arterial blood before and after passage of the charcoal column and behind the dialyzer cartridge. Results show a rapid metabolic degradation of carbromal including cleavage of bromide. Besides carbromal and its main metabolite 2-brome-2-ethylbutyramide (=carbromide) debromised organic metabolites appear to be responsible for the severity of the intoxication. Bromide plays no role in the pathogenesis of acute intoxication. Carbromal and its organic metabolites are eliminated through a large surface dialyzer almost as effectively as with charcoal hemoperfusion. The effectivity of detoxication is enhanced by the combination of both procedures. Free bromide is not adsorbed at charcoal but is readily dialyzable. Values of carbromal, calculated out of bromide levels, do not correspond to directly measured blood levels. Treatment of carbromal intoxication with combined hemoperfusion-hemodialysis should be performed early in all severe, risky or otherwise complicated cases until the patients awakens.