Modes Of Continuous Renal Replacement Therapy Research Articles

Extracorporeal Membrane Oxygenation for Coronavirus Disease 2019 in Shanghai, China.

Severe cases of coronavirus disease 2019 (COVID-19) cannot be adequately managed with mechanical ventilation alone. The role and outcome of extracorporeal membrane oxygenation (ECMO) in the management of COVID-19 is currently unclear. Eight COVID-19 patients have received ECMO support in Shanghai with seven with venovenous (VV) ECMO support and one veno arterial (VA) ECMO during cardiopulmonary resuscitation. As of March 25, 2020, four patients died (50% mortality), three patients (37.5%) were successfully weaned off ECMO after 22, 40, and 47 days support, respectively, but remain on mechanical ventilation. One patient is still on VV ECMO with mechanical ventilation. The partial pressure of oxygen/fractional of inspired oxygen ratio before ECMO initiation was between 54 and 76, and all were well below 100. The duration of mechanical ventilation before ECMO ranged from 4 to 21 days. Except the one emergent VA ECMO during cardiopulmonary resuscitation, other patients were on ECMO support for between 18 and 47 days. In conclusion, ensuring effective, timely, and safe ECMO support in COVID-19 is key to improving clinical outcomes. Extracorporeal membrane oxygenation support might be an integral part of the critical care provided for COVID-19 patients in centers with advanced ECMO expertise.

New modes of continuous renal replacement therapy using a refiltering technique to reduce micronutrient loss.

Micronutrient depletion is a major drawback of high-dose continuous renal replacement therapy (CRRT). We tested two novel CRRT modes, double-filtration hemofiltration (DHF) and dialysate-recycling hemodiafiltration (DHDF), aimed at reducing micronutrient loss while maintaining a high clearance rate of midsized solutes comparable to that of high-volume hemofiltration (HVHF). Forty patients with renal failure requiring CRRT were randomly assigned to receive predilutional standard-volume hemofiltration (SVHF, effluent rate 35 mL/kg/h), predilutional HVHF (100 mL/kg/h), DHF (35 mL/kg/h), and DHDF (30 mL/kg/h). In the two novel modes of CRRT, part of the high-volume primary effluent fluid produced by a high-flux filter (AV600S) was refiltered by two low-flux filters (15 L) for recycling as replacement fluid in DHF and dialysate in DHDF, while the remainder was discarded as final effluent fluid. Specimens were collected for measurement of trace elements, folic acid, amino acids (AAs), β2-microglobulin, cystatin C, and creatinine and for calculation of solute clearance. The clearance of 17 AAs, phosphorus, folic acid, copper, and zinc by DHF and DHDF was much lower than that by HVHF and comparable to that by SVHF. The estimated amount of AA loss by SVHF, HVHF, DHF, and DHDF was 10.3 (7.2-13.4) g/d, 22.1 (17.8-24.0) g/d, 10.6 (8.6-14.0) g/d, and 10.0 (8.6-11.4) g/d, respectively. Clearance of cystatin C and β2-microglobulin by DHF and DHDF was much greater than that by SVHF and equal to that by HVHF. Compared to HVHF, DHF, and DHDF have an equal capacity for removal of large solutes but show substantially reduced micronutrient loss.

Comparison between predilution and postdilution continuous renal replacement therapy (CRRT) for patients with MODS

Objective To comparie the effects of pre-dilution with post-dilution continuous renal replacement therapy (CRRT) for patients with MODS. Method Thirty-two MODS patients admitted to ICU (Intensive Care Unit ) were randomized and treated with different modes of CRRT. The results of creatinine clearance, acid-base equilibrium, haemodynamic variables before and post therapy were recorded.The maximal pre-filter pressure, the duration of filter unworn out and mortality of patients treated with different modes of CRRT were also recorded. Results Seventeen patients were treated with pre-dilution mode of CRRT and 15 patients treated with post-dilution mode of CRRT. After 24 hours of pre- and postdilution modes of CRRT, the net increase in Ccr (namely the rate of replacement creatinine clearance) were (15.6±4.6) vs. (22.7 ±4. 1) mL/min respectively (P＜0.01); after 48-hour, they were (14.9±3.3)vs. ( 18. 9 ±2. 3) mL/min (p ＜0. 05) . Both dilution modes could improve the blood PH、 HCO3- and BE( P ＜ 0. 05 ) without significant differences between two groups after CRRT therapy ( P ＞ 0. 05 ) . The MAP of patients treated with pre-dilution modes of CRRT therapy for 24 hours and the MAP of patients before therapy were 69. 2 ± 4. 6 and 56. 7 + 9. 1 mmHg respectively ( P ＜ 0. 05 ), and dosage of dopamine used in patients before CRRT therapy and that after CRRT for 24 hours were ( 11.20 +3.45 ) vs (6. 12 +3.41 ) μg ·kg-1 min -1(P＜0.05).The maximal pre-filter pressures of pre-and post-dilution modes were (82.23+9.11) cm H2O, (110.56 +28. 14) cmH2O respectively (P＜0.05), and the durations of lasting effect of filter used in two modes of CRRT were ( 39 + 28. 12 ) vs. ( 25 + 14. 45 ) h respectively ( P ＜0. 05) . Both dilution modes could improve APACHE Scores. There were no significant differences in APACHE Scores and mortalities between two groups after CRRT therapy. Conclusions Post-dilution mode of CRRT has higher filtration rate, but have higher maximal pre-filter pressure and shorter longevity of filter.Pre-dilution mode of CRRT has better effect on improving hemodynamics, reducing usage of vasopressor.Both modes of CRRT can correct acid base equilibrium disorder rapidly. There are no differences in the results of blood gas analysis improved、 APACHE scores and mortality between the two groups. Key words: Continuous renal replacement therapy (CRRT); Multiple organs dysfunction syndrome (MODS); Predilution; Postdilution

Using Imipenem and Cilastatin During Continuous Renal Replacement Therapy

To identify and review studies which have sought to define the pharmacokinetics of imipenem and cilastatin in patients receiving continuous renal replacement therapy (CRRT). Literature was primarily identified using Pharmline, Embase and Medline databases using the search terms "imipenem," "haemofiltration," "haemodialysis" and "pharmacokinetics." Papers that discussed only intermittent haemodialysis were excluded. Seven papers were identified which described the pharmacokinetics of imipenem in patients receiving CRRT. Four different modes of CRRT were used. The methods of sampling, dosages used and assumptions made during pharmacokinetic calculations varied widely between the studies. Total body clearance of imipenem during CRRT in patients suffering from acute renal failure was found to range between 89 and 149 ml/min. Total body clearance of cilastatin ranged between 9 and 32 ml/min. Total body clearance of both imipenem and cilastatin was reduced in patients with chronic renal failure. Total body clearance of cilastatin was also reduced by impaired liver function. Dose recommendations made ranged between 500 mg 6-hourly and 500 mg 12-hourly. The heterogeneity of the studies identified prevents them being analysed as a single group. For meaningful dosage recommendations to be made, further studies are required using larger populations and with more detail regarding liver dysfunction and duration of renal failure.

Identification of Proteins in Slow Continuous Ultrafiltrate by Reversed-Phase Chromatography and Proteomics

Continuous modes of renal replacement therapy (CRRT) are increasingly being utilized in the intensive care unit. The removal of cytokines and other inflammatory proteins during ultrafiltration may be responsible for some of the beneficial effects of CRRT. We used proteomic tools to identify proteins found in the ultrafiltrate from a patient with acute renal failure. Identification of these proteins could help elucidate the mechanism(s) of improved outcome with continuous renal replacement therapy. Protein was loaded on a reversed-phase C4 column and eluted with stepwise isocratic flows starting with 0%, 5%, 10%, 25%, and 50% of acetonitrile. Effluent was collected, pooled, desalted, and separated by two-dimensional gel electrophoresis (2DE). Reversed-phase separation improved the resolution and the number of spots seen on the gels. Protein spots were digested with trypsin and spotted onto MALDI plates. Proteins were identified by either peptide mass fingerprinting using a MALDI-TOF mass spectrometer or by peptide sequencing using a MALDI-TOF/TOF tandem mass spectrometer. From 196 spots cut, 47 were identified, representing multiple charge forms of 10 different proteins. Proteins identified were albumin, apolipoprotein A-IV, beta-2-microglobulin, lithostathine, mannose-binding lectin associated serine protease 2 associated protein, plasma retinol-binding protein, transferrin, transthyretin, vitamin D-binding protein and Zn alpha-2 glycoprotein. Continuous renal replacement therapy is frequently used in acutely ill patients with renal failure. Removal of proteins occurs during this process. The physiological significance of this protein removal is unclear. Identification of these proteins will lead to better understanding of the role of protein removal in continuous renal replacement therapy.