Antibiotics Removal by Continuous Venovenous Hemofiltration with a Novel Asymmetric Triacetate Membrane Hemofilter: An in vitro Study

Antibiotic Therapy in the Critically Ill with Acute Renal Failure and Renal Replacement Therapy: A Narrative Review

The outcome for critically ill patients is burdened by a double mortality rate and a longer hospital stay in the case of sepsis or septic shock. The adequate use of antibiotics may impact on the outcome since they may affect the pharmacokinetics (Pk) and pharmacodynamics (Pd) of antibiotics in such patients. Acute renal failure (ARF) occurs in about 50% of septic patients, and the consequent need for continuous renal replacement therapy (CRRT) makes the renal elimination rate of most antibiotics highly variable. Antibiotics doses should be reduced in patients experiencing ARF, in accordance with the glomerular filtration rate (GFR), whereas posology should be increased in the case of CRRT. Since different settings of CRRT may be used, identifying a standard dosage of antibiotics is very difficult, because there is a risk of both oversimplification and failing the therapeutic efficacy. Indeed, it has been seen that, in over 25% of cases, the antibiotic therapy does not reach the necessary concentration target mainly due to lack of the proper minimal inhibitory concentration (MIC) achievement. The aim of this narrative review is to clarify whether shared algorithms exist, allowing them to inform the daily practice in the proper antibiotics posology for critically ill patients undergoing CRRT.

Vancomycin therapeutic drug monitoring in patients on continuous renal replacement therapy: a retrospective study

Objectives

This study aimed to investigate vancomycin therapeutic drug monitoring (TDM) in patients on continuous renal replacement therapy (CRRT) and explore the risk factors for exceeding the target concentration.

Methods

This retrospective study enrolled patients aged ≥18 years who were admitted to the intensive care unit and treated with ≥3 intravenous vancomycin doses during CRRT, and who underwent vancomycin TDM. Demographic and other information were collected. Multivariate logistic regression was used assess the risk factors for exceeding the target concentration.

Results

Sixty-nine patients were included, and 40.6% patients underwent TDM. Additionally, 14.5% of patients reached the optimal concentration, and 87.5% of patients who exceeded the target received a daily dose adjustment. The cumulative dose of vancomycin and serum albumin were risk factors for exceeding the target concentration in patients on CRRT.

Conclusions

Patients on CRRT did not meet the optimal vancomycin management; <50% of the patients routinely received vancomycin TDM, and <15% achieved the optimal concentration. Fewer patients in the subtherapeutic group received a daily dose adjustment than those who exceeded the target concentration. Cumulative vancomycin and serum albumin doses before TDM were the risk factors for exceeding the target concentration in CRRT patients.

Comprehensive analysis of cytokine adsorption properties of polymethyl methacrylate (PMMA) membrane material

In acute kidney injury caused by sepsis (septic AKI), excessive production of inflammatory mediators is believed to be involved in deterioration of the disease. Renal replacement therapy using a polymethyl methacrylate (PMMA) membrane hemofilter improves the pathological condition of septic AKI by adsorbing and removing inflammatory cytokines. However, the adsorption properties of the PMMA membrane are unclear. In this study, we comprehensively analyzed the adsorption of 48 different cytokines in human plasma to PMMA and polysulfone (PS) membranes. Seventy-nine percent (38/48) of the cytokines were adsorbed more efficiently to the PMMA membrane than the PS membrane, which indicates that the PMMA membrane has high cytokine adsorption ability. The adsorption rate tended to be higher for the cytokines with lower molecular weight, and there was a significant correlation between the molecular weight of the cytokines and the adsorption rates. Electron microscopy showed that the PMMA hollow fiber membrane had a uniform internal structure from the inner to the outer layers of the membrane and had nano-pores inside the membrane that may have contributed to the adsorption of proteins with a specific molecular weight range. The clinical efficacy of a PMMA membrane hemofilter with cytokine adsorption properties against septic AKI needs further investigation including the evaluation of filtration performance of the hemofilters.