[Experience with inline intermittent hemodiafiltration as renal replacement therapy in critically ill patients]. / Hemodiafiltración intermitente en línea como terapia de reemplazo renal en paciente crítico: Experiencia en un centro de diálisis de agudo.

BACKGROUND: In critical patients with acute renal failure, intermittent diffusive renal replacement techniques cause hemodynamic problems due to their high depurative efficiency. This situation is avoided using continuous low efficiency therapies, which are expensive, prevent patient mobilization and add hemorrhagic risk due to systemic anticoagulation. Intermittent and prolonged hemodiafiltration (HDF) has the depurative benefits of diffusion, plus the positive attributes of convection in a less expensive therapy. AIM: To report our experience with intermittent and prolonged on-line HDF in critically ill patients. PATIENTS AND METHODS: During 2016, HDF therapies performed on critical patients with indication of renal replacement therapy were characterized. The hemodynamic profile was evaluated (doses of noradrenaline, blood pressure, heart rate and perfusion parameters). RESULTS: Fifty-one therapies were performed in 25 critical patients, aged 58 ± 11 years (28% women), with an APACHE II score of 22.1 ±10. The average time of the therapies was 4.15 hours (range 3-8 hours), the replacement volume was 75 ± 18 mL/kg/h and ultrafiltration rate was 226 ± 207 mL/h. The mean initial, maximum and final noradrenaline doses were 0.07 ± 0.1, 0.13 ±0.18 and 0.09 ±0.16 µg/kg/min respectively. No differences between patients with low, medium and high doses of noradrenaline or dose increases during therapy, were observed. The greatest decrease in mean arterial pressure was 15.3% and the maximum increase in heart rate was 12.8%. Anticoagulation was not required in 88% of therapies. CONCLUSIONS: High-volume intermittent or prolonged HDF is an effective therapy in critical patients, with good hemodynamic tolerability, lower costs and avoidance of systemic anticoagulation risks.

Incorporation of Chitosan in Polyurethanes Based on Modified Castor Oil for Cardiovascular Applications.

The increased demand for vascular grafts for the treatment of cardiovascular diseases has led to the search for novel biomaterials that can achieve the properties of the tissue. According to this, the investigation of polyurethanes has been a promising approach to overcome the present limitations. However, some biological properties remain to be overcome, such as thrombogenicity and hemocompatibility, among others. This paper aims to synthesize polyurethanes based on castor oil and castor oil transesterified with triethanolamine (TEA) and pentaerythritol (PE) and with the incorporation of 1% chitosan. Analysis of the wettability, enzymatic degradation, mechanical properties (tensile strength and elongation at break), and thermal stability was performed. Along with the evaluation of the cytotoxicity against mouse fibroblast (L929) and human dermal fibroblast (HDFa) cells, the hemolysis rate and platelet adhesion were determined. The castor-oil-based polyurethanes with and without 1% chitosan posed hydrophobic surfaces and water absorptions of less than 2% and enzymatic degradation below 0.5%. Also, they were thermally stable until 300 °C, with tensile strength like cardiovascular tissues. The synthesized castor oil/chitosan polyurethanes are non-cytotoxic (cell viabilities above 80%) to L929 and HDFa cells and non-thrombogenic and non-hemolytic (less than 2%); therefore, they are suitable for cardiovascular applications.

Why Polyurethanes Have Been Used in the Manufacture and Design of Cardiovascular Devices: A Systematic Review.

We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement to ascertain why polyurethanes (PUs) have been used in the manufacture and design of cardiovascular devices. A complete database search was performed with PubMed, Scopus, and Web of Science as the information sources. The search period ranged from 1 January 2005 to 31 December 2019. We recovered 1552 articles in the first stage. After the duplicate selection and extraction procedures, a total of 21 papers were included in the analysis. We concluded that polyurethanes are being applied in medical devices because they have the capability to tolerate contractile forces that originate during the cardiac cycle without undergoing plastic deformation or failure, and the capability to imitate the behaviors of different tissues. Studies have reported that polyurethanes cause severe problems when applied in blood-contacting devices that are implanted for long periods. However, the chemical compositions and surface characteristics of polyurethanes can be modified to improve their mechanical properties, blood compatibility, and endothelial cell adhesion, and to reduce their protein adhesion. These modifications enable the use of polyurethanes in the manufacture and design of cardiovascular devices.

Influence of Polyol/Crosslinker Blend Composition on Phase Separation and Thermo-Mechanical Properties of Polyurethane Thin Films.

Polyurethanes (PUs) from Polyethylene glycol (PEG) and polycaprolactone diol (PCL) and a crosslinker, Pentaerythritol (PE), were synthetized with isophorone diisocyanate (IPDI). In this study, we investigated the effect of polyol and crosslinker composition on phase separation and thermo-mechanical properties. The properties were studied through dynamic mechanical analysis, X-ray scattering, atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The results showed changes in PUs properties, microphase structure, and separation due to the composition of polyol/crosslinker blend. So, the largest concentration of PE produced multimodal loss factor patterns, indicating segment segregation while PUs with a PEG/PCL = 1 displayed a monomodal loss factor pattern, indicating a homogeneously distributed microphase separation. Additionally, the increase of the PEG concentration enhanced the damping capacity. On the other hand, agglomeration and thread-like structures of hard segments (HS) were observed through AFM. Finally, the thermal behavior of PUs was affected by chemical composition. Lower concentration of PE reduced the crosslinking; hence, the temperature with the maximum degradation rate.

Rapid screening fluorescence method applied to detection and quantitation of paralytic shellfish toxins in invertebrate marine vectors.

A rapid screening method is described for the determination of paralytic shellfish toxins (PST), in fresh marine vectors (bivalves and gastropods), at levels ranging from 0.05 to 5.0 mg STX-eq kg-1. PST are extracted from marine vector homogenates with acetic acid according to the Pre-COX-LC-FLD method. At the same time, the obtained extract is oxidised simultaneously in hydrogen peroxide and periodate oxidate to determine PST, non-N-hydroxylated and N-hydroxylated toxins, respectively. Then, they are analysed using a microplate fluorometer (Ex: 335 nm/Em: 405 nm). All the samples were compared with the liquid chromatography post-column oxidation method. Recoveries of PST added to fresh and processed marine vectors averaged 93.9% with a coefficient of variation of 6.1%. Both methods showed a good linear regression (r2 = 0.97). The method shows good intra- and inter-day precisions with a relative coefficient of variation of ≈ 3.8% and 5.7%, respectively. The limit of quantification of the rapid screening fluorescence method was ≈ 0.082 mg STX-eq kg-1, with ≤5% false positives. The established rapid screening fluorescence methods offer highly effective and verifiable pre-analyses of PST contamination in marine vectors and can be used for routine screening of the PST in seafood before formal identification by confirmatory methods (Pre-COX LC-FLD method, Lawrence method).

Hemodiafiltración intermitente en línea como terapia de reemplazo renal en paciente crítico: Experiencia en un centro de diálisis de agudo / Experience with inline intermittent hemodiafiltration as renal replacement therapy in critically ill patients

Background: In critical patients with acute renal failure, intermittent diffusive renal replacement techniques cause hemodynamic problems due to their high depurative efficiency. This situation is avoided using continuous low efficiency therapies, which are expensive, prevent patient mobilization and add hemorrhagic risk due to systemic anticoagulation. Intermittent and prolonged hemodiafiltration (HDF) has the depurative benefits of diffusion, plus the positive attributes of convection in a less expensive therapy. Aim: To report our experience with intermittent and prolonged on-line HDF in critically ill patients. Patients and Methods: During 2016, HDF therapies performed on critical patients with indication of renal replacement therapy were characterized. The hemodynamic profile was evaluated (doses of noradrenaline, blood pressure, heart rate and perfusion parameters). Results: Fifty-one therapies were performed in 25 critical patients, aged 58 ± 11 years (28% women), with an APACHE II score of 22.1 ±10. The average time of the therapies was 4.15 hours (range 3-8 hours), the replacement volume was 75 ± 18 mL/kg/h and ultrafiltration rate was 226 ± 207 mL/h. The mean initial, maximum and final noradrenaline doses were 0.07 ± 0.1, 0.13 ±0.18 and 0.09 ±0.16 μg/kg/min respectively. No differences between patients with low, medium and high doses of noradrenaline or dose increases during therapy, were observed. The greatest decrease in mean arterial pressure was 15.3% and the maximum increase in heart rate was 12.8%. Anticoagulation was not required in 88% of therapies. Conclusions: High-volume intermittent or prolonged HDF is an effective therapy in critical patients, with good hemodynamic tolerability, lower costs and avoidance of systemic anticoagulation risks.

Human milk feeding prevents retinopathy of prematurity (ROP) in preterm VLBW neonates.

BACKGROUND: Retinopathy of prematurity (ROP) is a multifactorial disease, but little is known about its relationships with neonatal nutritional policies. Human, maternal milk is the best possible nutritional option for all premature infants, including those at high risk for severe complications of prematurity, such as ROP. OBJECTIVE: This is a secondary analysis of data collected during two multicenter RCTs performed consecutively (years 2004 through 2008) by a network of eleven tertiary NICUs in Italy. The two trials aimed at assessing effectiveness of fluconazole prophylaxis (Manzoni et al., N Engl J Med 2007 Jun 14;356(24):2483-95), and of bovine lactoferrin supplementation (Manzoni et al., JAMA 2009 Oct 7;302(13):1421-8), in prevention of invasive fungal infection, and of late-onset sepsis in VLBW infants, respectively. We tested the hypothesis that exclusive feeding with fresh maternal milk may prevent ROP of any stage - as defined by the ETROP study - in VLBW neonates, compared to formula feeding. METHODS: We analyzed the database from both trials. Systematic screening for detection of ROP was part of the protocol of both studies. The definition of threshold ROP was as defined by the ETROP study. Univariate analysis was performed to look for significant associations between ROP and several possible associated factors, and among them, the type of milk feeding (maternal milk or formula for preterms). When an association was indicated by p < 0.05, multiple logistic regression was used to determine the factors significantly associated with ROP. RESULTS: In both trials combined, 314 infants received exclusively human maternal milk (group A), and 184 a preterm formula because their mothers were not expected to breastfeed. The clinical, demographical and management characteristics of the neonates did not differ between the two groups, particularly related to the presence of the known risk factors for ROP. Overall, ROP incidence (any stage) was significantly lower in infants fed maternal milk (11 of 314; 3.5%) as compared to formula-fed neonates (29 of 184; 15.8%) (RR 0.14; 95% CI 0.12-0.62; p = 0.004). The same occurred for threshold ROP (1.3% vs. 12.3%, respectively; RR 0.19; 95% CI 0.05-0.69; p = 0.009). At multivariate logistic regression controlling for potentially confounding factors that were significantly associated to ROP (any stage) at univariate analysis (birth weight, gestational age, days on supplemental oxygen, systemic fungal infection, outborn, hyperglycaemia), type of milk feeding retained significance, human maternal milk being protective with p = 0.01. CONCLUSIONS: Exclusive human, maternal milk feeding since birth may prevent ROP of any stage in VLBW infants in the NICU.