Georges Ouellet

Hemoperfusion for the treatment of poisoning: technology, determinants of poison clearance, and application in clinical practice.

Hemoperfusion is an extracorporeal treatment based on adsorption, historically reserved for the treatment of acute poisonings. Its use was popularized in the 1970s after several in vitro and animal experiments had demonstrated its efficacy, and was even preferred over hemodialysis in the management of overdosed patients.

Available Extracorporeal Treatments for Poisoning: Overview and Limitations

Poisoning is a significant public health problem. In severe cases, extracorporeal treatments (ECTRs) may be required to prevent or reverse major toxicity. Available ECTRs include intermittent hemodialysis, sustained low‐efficiency dialysis, intermittent hemofiltration and hemodiafiltration, continuous renal replacement therapy, hemoperfusion, therapeutic plasma exchange, exchange transfusion, peritoneal dialysis, albumin dialysis, cerebrospinal fluid exchange, and extracorporeal life support. The aim of this article was to provide an overview of the technical aspects, as well as the potential indications and limitations of the different ECTRs used for poisoned patients.

A stepwise approach for the management of poisoning with extracorporeal treatments.

The use of an extracorporeal treatment (ECTR) in a poisoned patient may be life‐saving in a limited number of scenarios. The decision‐processes surrounding the use of ECTR in poisoning is complex: most nephrologists are not trained to assess a poisoned patient while clinical toxicologists rarely prescribe ECTRs. Deciding on which ECTR is most appropriate for a poison requires a good understanding of the poisons physicochemical and pharmacokinetic properties. Further, a detailed understanding of the capabilities and limitations of the different ECTRs can be useful to select the most appropriate ECTR for a given clinical situation. This manuscript provides a stepwise approach to assess the usefulness of ECTRs in poisoning.

Does Concomitant Administration of Sevelamer and Calcium Carbonate Modify the Control of Phosphatemia

There is no guideline regarding the concomitant or distant administration of sevelamer and calcium carbonate. Our aim was to determine whether serum phosphate varied when sevelamer and calcium carbonate were administered concomitantly in comparison to administration at separate meals. Fourteen chronic hemodialysis patients were enrolled in this cross‐over, randomized trial. Each subject underwent two four‐week study periods. During the “concomitant” period, subjects were instructed to take both sevelamer and calcium carbonate together at each meal, whereas in the “separate” period, they were required to take them at separate meals. The order of the “concomitant” and “separate” periods was randomized. Phosphate‐binding agents were stopped for a one‐week washout period before each study period. The total dose of sevelamer and calcium carbonate for each subject remained the same for the whole duration of the study and had been determined according to their usual dose of phosphate binders. Patients were instructed to keep their usual eating habits constant and a nutritionist evaluated the daily phosphate intake three times per week. Dialysis parameters were kept constant. Pre‐dialysis serum phosphate, calcium, bicarbonate, and albumin were measured at the end of each week. The average daily dietary phosphate intake remained unchanged throughout the study. At the end of the two study periods there was no significant difference in serum phosphate (1.50 ± 0.46 mmol/L in the “concomitant” period vs. 1.51 ± 0.31 mmol/L in the “separate” period, P = 0.97), calcium (2.26 ± 0.19 mmol/L in the “concomitant” period vs. 2.27 ± 0.15 mmol/L in the “separate” period, P = 0.64), calcium × phosphate product (3.36 ± 0.94 mmol2/L2 in the “concomitant” period vs. 3.41 ± 0.71 mmol2/L2 in the “separate” period, P = 0.84) and bicarbonate levels (21.5 ± 3.3 mmol/L for the “concomitant” period vs. 21.6 ± 3.1 mmol/L for the “separate” period, P = 0.81). Our results show that simultaneous administration of calcium carbonate and sevelamer does not decrease phosphate‐binding capacity. Hence, patients can choose to take their phosphate binders concomitantly or at separate meals, according to their preference.

Hypo-uricémie rénale héréditaire chez un sujet d’origine caucasienne : présentation d’un cas clinique et revue de la littérature

Hereditary renal hypouricemia is characterized by a decreased serum uric acid, a uric acid fractional excretion above normal and the absence of another cause of hyperuricosuric hypouricemia. This pathology, generally caused by a mutation of urate renal transporter URAT1, is relatively common in Asia, but occurs very infrequently in Caucasian populations. The diseases association with exercise-induced acute renal failure is well known. This article reports the case of a 47-year-old man of Italian origin who was diagnosed with hereditary renal hypouricemia after an episode of exercise-induced acute renal failure. Molecular analysis of SLC22A12 encoding URAT1 for renal hypouricemia using peripheral blood genomic DNA of the patient was performed. Single-strand conformation polymorphism screening, amplification, and direct sequencing of SLC22A12 revealed no mutation in this patient. This suggests that another gene can be involved in this disease.

Pharmacokinetic and Dynamic of Furosemide in Peritoneal Dialysis Patients

The aim of our study was to evaluate the efficacy and bioavailibility of a commonly used oral furosemide dose (500 mg) compared to a 250 mg intravenous (IV) dose in PD patients with significant residual renal function (urine volume > 100 mL). We also evaluated the immediate blood pressure effect in these patients. The data were obtained from a study we performed for the homologation of a 500-mg dose of furosemide by Health Canada.

High mortality after pelvis and lower limb fractures in ESRD

Sir, The high mortality rate associated with hip fracture in the general population, as well as in the end-stage renal disease (ESRD) population, is well described. However, the mortality associated with pelvis and lower limb fractures in ESRD patients remains unknown. We reviewed the medical records of all chronic haemodialysis or peritoneal dialysis patients hospitalized at Maisonneuve-Rosemont Hospital for a fracture from 1 July 1995 to 1 February 2007. Femoral neck, pelvis, femoral condyle, tibial plateau, patella, tibia and malleolus fractures were considered. Femoral neck and pelvis fractures were analysed separately, while the other fractures were analysed together as lower limb fractures. All patients who died during the study period were identified and mortality rates were calculated. During the 127-month-long study period, 60 dialysis patients were hospitalized for a total of 68 fractures. Seven patients had two fracture episodes, and one patient had three fracture episodes. The three most common fracture sites were hip (40 cases), pelvis (13 cases) and malleolus (8 cases) (Table 1). The 1-year mortality rate after a hip fracture was 42.5% (17 patients), with an in-hospital mortality rate of 20%. Two patients died during their hospitalization for a pelvis or lower limb fracture. One-year mortality rates were 30.8% after a pelvis fracture and 20% after a lower limb fracture. Median survival during the observation period was 427 days after a pelvis fracture and 581 days after a lower limb fracture. Hip fracture is associated with a 1-year mortality rate of 24% in the general population [1]. In ESRD, the 1-year mortalityrateafterahipfractureapproximates50%[2].Our results are consistent with previously reported mortality rates. Few studies have described the mortality associated with pelvis or lower limb fractures in the general population. In a British study, the 1-year mortality rates were 8.7% after pelvis fracture and 2.4% after a lower limb fracture [3]. In our ESRD cohort, the 1-year mortality rates for pelvis and lower limb fractures were increased 3.5- and 8.3-fold, respectively. In fact, the impact of pelvis and lower limb fractures on mortality in ESRD patients appears very similar to the impact of hip fracture in the general population. Like hip fractures [4,5], pelvis and lower limb fractures are probably markers of poor nutritional and general health status in this population. With a 1-year mortality rate similar to that of hip fracture in the general population, our data delineate for the first time the poor outcomes associated with pelvis and lower limb fractures in ESRD patients. The incidence, risk factors, clinical and functional outcomes of such fractures in ESRDpatientsneedtobeevaluatedinlarger,registry-based studies.

Association of Neutrophil-to-Lymphocyte Ratio With Inflammation and Erythropoietin Resistance in Chronic Dialysis Patients:

Background: Neutrophil-to-lymphocyte ratio (NLR) was widely studied as a prognostic marker in various medical and surgical specialties, but its significance in nephrology is not yet established. Objective: We evaluated its accuracy as an inflammation biomarker in a dialysis population. Design setting: Single-center retrospective study. Patients: The records of all 550 patients who were treated with hemodialysis (HD) or peritoneal dialysis (PD) from September 2008 to March 2011 were included. Measurements: NLR was calculated from the monthly complete blood count. Methods: Association between NLR and markers of inflammation (C-reactive protein [CRP], serum albumin, and erythropoietin resistance index [ERI]) was measured using Spearman coefficient. Results: In total, 120 patients were eligible for the correlation analyses. We found a positive correlation between NLR and CRP (all patients: r = 0.45, P < .001; HD: r = 0.47, P < .001; PD: r = 0.48, P = .13). NLR and albumin were inversely correlated (r = −0.51, P < .001). Finally, high NLR was associated with a nonsignificant increased ERI, but we have not demonstrated a direct correlation. Limitations: CRP and albumin are not measured routinely and were ordered for a specific clinical reason leading to an indication bias. Also, no relationship with clinical outcome was established. Conclusions: NLR seems to be a good inflammatory biomarker in dialysis in addition to being easily available. However, controlled studies should be conducted to properly assess and validate NLR levels that would be clinically significant and relevant, as well as its prognostic significance and utility in a clinical setting.