Substitution of acetic acid for hydrochloric acid in the bicarbonate buffered dialysate.

In a multicenter study including 5 dialysis units, blood acetate changes during 4 h dialysis sessions in 141 patients treated with a 4 mM acetate-containing bicarbonate dialysate (ABD) were evaluated and compared to the values of 114 patients using an acetate-free bicarbonate dialysate (AFD). Acetate-free bicarbonate dialysate was delivered by a dialysis machine from the mixing with water for dialysis of a 1/26.2 bicarbonate concentrate, and a 1/35 acid-concentrate in which acetic acid was substituted for hydrochloric acid (Soludia, Fourquevaux, France). This new type of dialysate was routinely in use for 3 years on average (range, from 2 to 5 years). All patients fasted before and during dialysis. Blood samples were withdrawn at the start and at the end of dialysis sessions. The acetate plasma concentration was determined using the acetyl-CoA synthetase enzymatic method (Boehringer, Manheim, Germany). In patients treated with ABD whose predialysis blood acetate levels were in the physiologic range of < or = 100 microM (n = 113), the acetate plasma concentration increased from a predialysis mean value of 22+/-3 microM to a postdialysis mean value of 222+/-11 microM in 88 patients (78% of patients) whereas the acetate plasma concentration changes remained in the range of physiologic values from 21+/-6 to 58+/-7 microM in the other 25 patients. In contrast, patients treated with AFD whose predialysis blood acetate levels were in the physiologic range (n = 108), acetate plasma concentration increased from a predialysis mean value of 49+/-6 microM to 160+/-19 microM in only 13 patients (12% of patients) whereas acetate plasma concentration changes remained in the range of physiologic values of 23+/-2 to 41+/-3 microM in most of the patients of this group. In this study, a significant number of patients, whether receiving standard or acetate-free bicarbonate dialysates, exhibited an extremely high acetate plasma concentration at the start of the dialysis session. Hyperacetatemia was controlled with AFD in patients whose predialysis acetate plasma concentration of 316+/-82 decreased to 55 +/-23 microM (n = 6) at the end of the dialysis session whereas the acetate plasma concentration remained high when the predialysis concentration was 580+/-76 microM, with a postdialysis concentration of 233+/-39 microM (n = 28). It is concluded that in patients whose predialysis blood acetate levels were in the physiologic range, acetate-containing bicarbonate dialysate induces hyperacetatemia whereas postdialysis blood acetate remains in the normal range in such dialysis patients treated with acetate-free dialysate. Chronic hyperacetatemia, which could be found in dialysis patients, is well controlled by dialysis using an acetate-free dialysate.

[Risk factors for acute hypersensitivity reactions in hemodialysis]. / Facteurs de risque des réactions aiguës d'hypersensibilité en hémodialyse: enquête prospective multicentrique sur six mois dans l'Ouest de la France.

The aim of this prospective study was to evaluate the prevalence of anaphylactoid reactions (AR) in patients dialysed with cellulose or synthetic membranes and the possible link with ACE inhibitors. Survey was conducted for six months (Jan, 1 to July, 1 1993). Thirty dialysis units treating 1573 patients (899 M and 674 F) were participating to the study. At the end of the period under study, only 1536 patients were included in the analysis. Prevalence of AR was calculated from 122 694 hemodialysis sessions. Thirty-three AR in 21 patients (1.3%) (8 M, 13 F), of which 8 severe AR in 5 patients (0.25%) were observed. Annual incidence of AR was 0.17 per 1000 sessions with cellulose membranes and 4.2 per 1000 sessions with synthetic membranes. Relative risk of the occurrence of AR was 10 to 20 times higher with synthetic membranes than cellulose membranes, and 3 to 4 times higher in patient treated with ACE inhibitors than in those no treated. Prevalence of AR with AN69 membrane (3.2%) was not significatively different from that with other synthetic membranes (1.6%). However, treatment with ACE inhibitors increased strongly the risk of AR in AN69 patients (7.2%) in comparison to patients treated with other synthetic membranes (1.6%) ( < 0.1). Prevalence of severe AR was 0.25% in total dialysed population, 0.5% in patient treated with synthetic membranes, 1.1% in AN69 patient and 4.9% in AN69 patients treated with ACE inhibitors. Relative risk of AR is at least 20 times higher in dialysed patients with ACE inhibitors (1.7%) than other dialysed patients without ACE inhibitors (0%). Seventy-two percent of AR occurred in 2/30 dialysis units, thus demonstrating the role of a "un effect". That suggest the role of a "third factor" in the occurrence of AR.

[Optimization of enoxaparin dose in the prevention of coagulation in the circuits of hemodialysis: results of a multicenter study]. / Optimisation de la dose d'énoxaparine (Lovenox) dans la prévention de la coagulation des circuits d'hémodialyse: résultats d'une étude multicentrique.

In order to define the optimal dosage of a low molecular weight enoxaparine (Lovenox) in the prevention of clotting in extracorporeal circulation during hemodialysis, a multicentre trial was conducted in 72 patients dialysed in seven hemodialysis units. During three weeks, these patients received as antithrombic treatment a single injection of enoxaparine at the beginning of the session. The initial dose fixed by previous data concerning dialysis with high hemorrhagic risks patients was 0.5 mg/kg (50 U1 Anti-Xa/kg). According to the evaluation of thrombotic manifestations during a 4 hour dialysis, the dosage was progressively increased if necessary for each patient. For 41% patients, the initial dose of 0.5 mg/kg was maintained along the whole study; 59% patients needed higher dose, between 0.6 and 0.9 mg/kg. The mean dose for the whole patient population at the end of the study was 0.62 +/- 0.16 mg/kg. No complication nor side effect was noted. The influence of blood flow, nature of dialysis membrane, level of hematocrit was studied. In conclusion, 0.5 mg/kg of enoxaparine can prevent thrombotic manifestations in almost half of chronic hemodialysed patients with good results. Further studies could precise the place of personal or technical parameters in the choice of the optimal dose for each patient.

[Chronological study of signs of myoclonic encephalopathy in hemodialysis patients (author's transl)]. / Etude chronologique des signes de l'encéphalopathie myoclonique des hémodialysés. Signes précurseurs et évolution chez douze patients.

Twelve patients with chronic renal failure, on maintenance hemodialysis have a stereotyped illness. The dialysate was made up from a high level aluminium tap water. After having been on haemodialysis for 10 to 12 months, they suffer from more and more acute osteodystrophic, osteomalacic symptoms. Then, distinctive EEG abnormalities appear. These first symptoms allow an early diagnosis of the progressive dialytic encephalopathy. The neurological symptoms appear some months later. Eight patients died from this encephalopathy. Four patients are still alive and are, from at least two years, on maintenance haemodialysis with a free aluminium water. In these 4 cases, the evolution of the disease is good: osteomalacic symptoms disappear in a year; the neurological symptoms are still present though transient. EEG abnormalities remain and blood aluminium level is about 100 micrograms/L. These cases show, once more, the significant role of aluminium as an aetiological factor in "progressive dialysis encephalopathy".

[Two forerunners of the encephalopathy of hemodialysed patients : osteomalacic osteodystrophy and electroencephalographic alterations. Influence of the aluminium concentration in the dialysis fluid (author's transl)]. / Deux signes précurseurs de l'encéphalopathie des hémodialysés: ostéodystrophie ostéomalacique et altérations électroencéophalographiques. Influence de la teneur en aluminium dans les bains de dialyse.

In a hemodialysis center where the dialysate fluid is rich in aluminium (200 microgram/l), 19 out of 23 patients presented an osteopathy which was severe in most cases. It was also noted that 16 patients showed encephalographic alterations occurring early on, revealed by repeated recordings, and classified in three stages according to severity : the most serious stage presents as paroxysmal bursts of high voltage waves and precedes the myoclonic encephalopathy of dialysed patients. Ten patients showed this complication, and 4 of them died of it. These findings are confronted with the minimal bone and brain alterations of 24 patients undergoing dialysis in another center where the treatment is identical with the exception of the low aluminium content of the dialysate fluid (25 microgram/l).