Elimination of fluconazole during continuous renal replacement therapy. An in vitro assessment

Introduction: Continuous renal replacement therapy (CRRT) efficiently eliminates fluconazole. However, the routes of elimination were not clarified. Adsorption of fluconazole by filters is a pending question. We studied the elimination of fluconazole in a model mimicking a session of CRRT in humans using the NeckEpur® model. Two filters were studied. Methods: The AV1000®-polysulfone filter with the Multifiltrate Pro. Fresenius and the ST150®-polyacrylonitrile filter with the Prismaflex. Baxter-Gambro were studied. Continuous filtration used a flowrate of 2.5 L/h in post-dilution only. Session were made in duplicate. Routes of elimination were assessed using the NeckEpur® model. Results: The mean measured initial fluconazole concentration (mean ± SD) for the four sessions in the central compartment (CC) was 14.9 ± 0.2 mg/L. The amount eliminated from the CC at the end of 6 h-session at a 2.5 L/h filtration flowrate for the AV1000®-polysulfone and the ST150®-polyacrylonitrile filters were 90%–93% and 96%–94%, respectively; the clearances from the central compartment (CC) were 2.5–2.6 and 2.4–2.3 L/h, respectively. The means of the instantaneous sieving coefficient were 0.94%–0.91% and 0.99%–0.91%, respectively. The percentages of the amount eliminated from the CC by filtration/adsorption were 100/0%–95/5% and 100/0%–100/0%, respectively. Conclusion: Neither the ST150®-polyacrylonitrile nor the AV1000®-polysulfone filters result in any significant adsorption of fluconazole.

Diafiltration flowrate is a determinant of the extent of adsorption of amikacin in renal replacement therapy using the ST150®-AN69 filter: An in vitro study

Introduction: In continuous renal replacement therapy, conduction and convection are controlled allowing prescribing dosage regimen improving survival. In contrast, adsorption is an uncontrolled property altering drug disposition. Whether adsorption depends on flowrates is unknown. We hypothesized an in vitro model may provide information in conditions mimicking continuous renal replacement therapy in humans. Methods: ST150®-AN69 filter and Prismaflex dialyzer, Baxter-Gambro were used. Simulated blood flowrate was set at 200 mL/min. The flowrates in the filtration (continuous filtration), dialysis (continuous dialysis), and diafiltration (continuous diafiltration) were 1500, 2500, and 4000 mL/h, respectively. Routes of elimination were assessed using NeckEpur® analysis. Results: The percentages of the total amount eliminated by continuous filtration, continuous dialysis, and continuous diafiltration were 82%, 86%, and 94%, respectively. Elimination by effluents and adsorption accounted for 42% ± 7% and 58% ± 5%, 57% ± 7% and 43% ± 6%, and 84% ± 6% and 16% ± 6% of amikacin elimination, respectively. There was a linear regression between flowrates and amikacin clearance: Y = 0.6 X ± 1.7 (R2 = 0.9782). Conversely, there was a linear inverse correlation between the magnitude of amikacin adsorption and flowrate: Y = –16.9 X ± 84.1 (R2 = 0.9976). Conclusion: Low flowrates resulted in predominant elimination by adsorption, accounting for 58% of the elimination of amikacin from the central compartment in the continuous filtration mode at 1500 mL/h of flowrate. Thereafter, the greater the flowrate, the lower the adsorption of amikacin in a linear manner. Flowrate is a major determinant of adsorption of amikacin. There was an about 17% decrease in the rate of adsorption per increase in the flowrate of 1 L/min.

Purification of emulsified oil by Bentonite loaded polyvinylidene fluoride/polyvinylpyrrolidone membrane

In this study, a Bentonite clay incorporated polyvinylfluoride (PVDF) and polyvinyl pyrrolidone (PVP) based adsorbent membrane was produced for the selective separation of oils from simulated wastewater. This membrane was produced as an intelligent material that selectively separates emulsified oils from water when it is used as adsorbent and purifies water when it is used in continuous membrane filtration. The affinity of the membrane to oil components was determined by water-oil uptake tests. The uptake experiments were conducted for soybean oil, hazelnut oil, lubricant oil and other volatile oils. As a result, membranes absorbed greater than 200 wt.% of oil when the membranes were immersed in the soybean oil, hazelnut oil and lubricant oil. When the same membranes were used for continuous filtration, greater than 85% of oil rejection values were obtained. As the PVP ratio in the membrane increased, flux values enhanced gradually. Bentonite incorporation simultaneously improved flux values and oil rejection remarkably. The soybean rejection increased from 69.1% to 90.9%, hazelnut oil rejection increased from 78% to 99.98%, and lubricant oil rejection enhanced from 80.5% to 96.5% when the bentonite amount was increased from 0 wt.% to 15 wt.%.

An unusual complication after endovascular aneurysm repair for giant abdominal aortic aneurysm with aortocaval fistula: High bilirubin levels

Abdominal aortic aneurysm has among its rare complications the aortocaval fistula. It is observed in less than 1% of all abdominal aortic aneurysms and represents 3%–7% of clinical presentation in case of rupture. A male patient was presented to the emergency department with pulsating mass with continuous vascular systo-diastolic bruit, located in the lower part of abdomen with the back pain radiating anteriorly in lower abdomen. After diagnosis of abdominal aortic aneurysm with aortocaval fistula, a trimodular Endurant endograft was placed. Migration of the endoprosthesis was treated with Endoanchor and endovascular aneurysm sealing device. In the postoperative course, the patient had jaundice due to high bilirubin levels, cholestasis and increased hepatocyte cytolysis: aspartate aminotransferase and alanine aminotransferase. The treatment with appropriate continuous filtration rapidly reduced bilirubin values and the patient gradually improved.

Continuous renal replacement therapy in the treatment of severe hyperkalemia: An in vitro study

Introduction: Continuous renal replacement therapy is not presently recommended in the treatment of life-threatening hyperkalemia. There are no specific recommendations in hemodialysis to treat hyperkalemia. We hypothesized an in vitro model may provide valuable information on the usefulness of continuous renal replacement therapy to treat severe hyperkalemia. Methods: A potassium-free solute was used instead of diluted blood for continuous renal replacement therapy with a simulated blood flowrate set at 200 mL/min. The mode of elimination included continuous filtration, continuous dialysis, and continuous diafiltration using a flowrate of 4000 mL/min for continuous filtration and continuous dialysis modes, and a ratio of 2500/1500 in the continuous diafiltration mode. Results: The mean initial potassium in the central compartment was 10.1 ± 0.4 mmol/L. The clearances in the continuous diafiltration, continuous filtration, and continuous dialysis were 3.4 ± 0.5, 3.6 ± 0.1, and 3.7 ± 0.1 L/h, respectively, not significantly different. Continuous dialysis resulted in the lowest workload for staff. Increasing the continuous dialysis flowrates from 2000 to 8000 mL/h increased clearance from 2.3 ± 0.3 to 6.2 ± 0.8 L/h. The delays in decreasing the potassium concentration to 5.5 mmol/L dropped from 120 to 45 min, respectively. Potassium eliminated in the first hour increased from 18 to 38 mmol that compared favorably with hemodialysis. Decrease in simulated blood flowrate from 200 to 50 mL/min moderately but significantly decreased the clearance from 3.7 to 3.0 L/h. Conclusion: Hyperkalemia is efficiently treated by continuous renal replacement therapy using the dialysis mode. Caution is needed to prevent the onset of severe hypokalemia within 40 min after initiation of the session.

Continuous-flow membrane filtration (CFMF) as a new method to study the narrow size fractions of colloidal dimension

In addition to the cascade filtering method, a new method of continuous-flow gel filtration (CFMF gel filtration) without replacing the filter septum has been developed and tested. The results of narrow size fractions separation from water samples with a high content of colloids (cascade filtration and continuous filtration) and the study of their migration with microelements are presented. An experimental investigation of the joint migration of a large number of elements (up to 40-60) and organic matter in continental waters demonstrates the high prospects for the methods to establish stable geochemical associations of trace elements adsorbed on colloids.