Synthetic Colloids Research Articles

Changes from 2012 to 2015 in intravenous fluid solutions issued to hospital departments.

In recent years, large trials have increased the level of evidence for intravenous (IV) fluid therapy, at least in the intensive care setting. It is less clear whether this change in the evidence base has been associated with changes in IV fluid use in different hospital departments. We obtained details from the regional pharmacy regarding IV fluids issued to hospital departments in the Danish Capitol Region from January 2012 to May 2015. We used paired Wilcoxon's signed-rank test to analyse changes in the issuing in different departments. Total regional issuing of IV fluids showed increase in crystalloid solutions (9%; P=0.001) and decrease in colloid solutions (59%; P=0.005). Subtype analysis showed increased issuing of buffered crystalloids (36%; P=0.001), human albumin (30%; P<0.0001) and decreased issuing in synthetic colloid solutions (82%; P<0.0001) from Q1 2012 to Q2 2015. At the departmental level, the issuing of synthetic colloid solutions decreased markedly to all settings. The issuing of buffered crystalloids increased to orthopaedic (226%; P=0.03) and to general surgery departments (686%; P=0.002). Albumin solutions were increasingly issued to anaesthesia departments (63%; P= 0.005) and was rarely issued to general surgery and orthopaedic departments. The issuing of IV fluid solutions to hospital departments has changed markedly over the last years to less colloid, in particular the synthetic solutions, and relatively more issuing of crystalloids, in particular the buffered solutions.

Does fluid management affect the occurrence of acute kidney injury?

To describe the potential impact of different fluid management strategies on renal outcomes in critically ill and postoperative patients. Uncritical fluid administration may induce renal compartment syndrome and renal venous congestion, which contribute to kidney dysfunction. In more than 5000 randomized surgical or septic patients, goal-directed therapy did not reduce fluid accumulation, acute kidney injury (AKI) development or need for renal replacement therapy. In contrast to synthetic colloids, which increase the risk of AKI, albumin solutions and balanced crystalloids appear well tolerated from a renal standpoint in medical and surgical patients requiring intensive care. However, any clinical benefits compared with 0.9% sodium chloride have not yet been demonstrated. Although synthetic colloids should be avoided in patients with or at risk of AKI, the renal efficacy of using albumin solutions and/or balanced crystalloids as alternatives to 0.9% sodium chloride in high-risk patients is yet to be confirmed or refuted. Improved goal-directed protocols, which minimize unnecessary fluid administration and reduce potentially harmful effects of fluid overload, need to be developed and tested.

Does small-volume resuscitation with crystalloids or colloids influence hemostasis and survival of rabbits subjected to lethal uncontrolled hemorrhage?

Prehospital, small-volume resuscitation of combat casualties with a synthetic colloid (6% hydroxyethyl starch [HES] 670/0.75) has been recommended when blood or blood components are unavailable. We studied hemostatic effects of a newer synthetic colloid (6% HES, 130/0.4) compared with either a natural colloid (albumin) or to crystalloids in an uncontrolled hemorrhage model. Spontaneously breathing New Zealand white rabbits (3.4 ± 0.1 kg) were anesthetized, instrumented, and subjected to a splenic injury with uncontrolled bleeding. Fifteen minutes after injury, rabbits were in shock (mean arterial pressure [MAP] = 26 ± 1.3 mm Hg, and received colloids (6% HES, 130/0.4 or 5% albumin at 15 mL/kg), or crystalloids (normal saline at 30 mL/kg or 5% hypertonic saline at 7.5 mL/kg) for resuscitation in two intravenous bolus injections (15 minutes apart) to raise their MAP to 65 mm Hg, n = 9/group. Animals were monitored for 2.5 hours or until death, and blood losses were measured. Blood samples were analyzed for arterial blood gas, complete blood count, and coagulation measures. There were no differences among groups in baseline measures and initial hemorrhage volume (11.9 ± 0.6 mL/kg) at 15 minutes postinjury. Twenty minutes after fluid resuscitation (1 hour postinjury), MAP was higher, shock indices were lower, and blood pH was higher in colloids versus. crystalloids groups (p < 0.05). Administration of 6% HES 130/0.4 colloid produced the largest hemodilution (54% decrease in hematocrit, p < 0.05 vs. hypertonic saline). Activated partial thromboplastin time increased approximately 35% above baseline in all groups except in 6% HES 130/0.4 group in which it doubled. Clot strength was reduced (15%) only in the 6% HES 130/0.4 group. 6% HES 130/0.4 resuscitation produced the largest blood loss and 33% survival rate that was not different than the crystalloid groups. Albumin produced the best hemostatic and survival outcomes (78%). Small-volume resuscitation with crystalloids appeared inadequate to treat hypovolemic shock and prevent death. 6% HES 130/0.4 was effective hemodynamically but detrimental to hemostasis. Albumin produced the best outcomes consistent with our previous observations. Further studies are needed to prove benefit of albumin solution as a possible resuscitation fluid for treating combat casualties at the point of injury.

Rheological Properties of Coating Colors Containing Biobased Latex

This paper focuses on the understanding of basic properties of water-swollen crosslinked starch nanoparticles as a function of crosslink density. The extent of their water swelling is decreased with increasing particle crosslink density and solid concentration and vice versa. This study elucidates the unique rheological properties of starch nanoparticle dispersions and paper coating formulations in comparison with water-soluble cooked starch and synthetic latex counterparts. These rheological studies extend over many decades of shear rates, using several different rheometers. Low shear viscosities were obtained using a Cannon-Fenske viscometer and a TA AR-2000 stress rheometer with double concentric cylinder geometry. Intermediate shear rate rheology was evaluated with a Hercules rheometer. High shear rates were studied with ACAV A2 ultra-high shear capillary and slit rheometers. Unlike conventional cooked and soluble starch solutions, starch nanoparticle latex dispersions are colloids that consist of internally crosslinked particles. With increasing intra-particle crosslink density these biobased colloids have been found to behave much like petroleum based synthetic latex colloids. However, at ultra-high shear their rheological properties are relatively more shear thinning compared to hard particles, including synthetic latex and pigment particles, which exhibit shear-thickening and dilatancy. The implications of the rheological data on high-speed coater runnability are discussed.

Postoperative Acute Kidney Injury and Blood Product Transfusion After Synthetic Colloid Use During Cardiac Surgery

This study assessed the effect of 2 types of hydroxyethyl starches (HES) on renal integrity and blood transfusion in cardiac surgery patients. Retrospective investigation. Patients from a single tertiary medical center. Inclusion criteria included coronary artery bypass graft (CABG) and/or valve surgery that included cardiopulmonary bypass with aortic cross-clamping. Intraoperative HES and blood product administration. The study comprised 1,265 patients who met inclusion criteria. Of these patients, 70% received HES, and of these, 47% received<1,000 mL and 53% received≥1,000 mL. There was no difference in the development of acute kidney injury between the 2 groups. A parsimonious propensity model for colloids showed that combined CABG and valve surgery were less likely to be associated with HES administration than was CABG alone (OR 0.68, confidence interval [CI] 0.46-0.97; p = 0.04). Intra-aortic balloon pump use was less likely to be associated with HES administration (OR 0.57, CI 0.38-0.86; p = 0.007). Patients with chronic kidney disease, stages 3 to 5, were less likely to receive HES, with an OR of 0.56 (CI 0.38-0.84; p = 0.004); 0.51 (CI 0.20-1.33; p = 0.170); and 0.23 (CI 0.12-0.44; p<0.0001), respectively, for each stage. No difference was noted in red blood cell transfusion. However, fresh frozen plasma, cryoprecipitate, and platelet transfusions were significantly higher with larger volumes of HES, with an OR of 2.03 (CI 1.64-2.52; p<0.001); 1.60 (CI 1.30-1.97; p<0.000); and 1.62 (CI 1.21-2.15; p = 0.006), respectively. No differences in surgical mortality were found between the colloid and noncolloid groups. This study showed no association of postoperative acute kidney injury and red blood cell transfusion between the colloid and noncolloid groups. Although the complication rate was higher with HES administration, there was no difference in surgery mortality between the 2 groups.

Controlled molecular assembly of self-propelled colloid motors and their biomedical applications

Synthetic colloid motors are the micro-/nanomachines which can harvest different types of energies into mechanical motion in the fluids. Since 2012, it has been one of important strategies for controlled fabrication of colloidal motors to combine effectively controlled molecular assembly (“bottom up”) with top-down approaches. Colloid motors based on controllable molecular assembly possess the advantages of: (1) mass production, (2) response to the external stimuli, and (3) access to multifunctionality. This review will summarize the progress on the controlled preparation, motion control, and biomedical applications of colloid motors through integrating multifunctional building blocks into assemblies. This review will also introduce the controlled preparation of bubble-propelled colloid motors based on layer-by-layer assembled microcapsules, nanotubes, shells, and two-dimensional plates, the fabrication of near-infrared-light-driven colloidal motors based on polyelectrolytic multilayer microcapsules and nanotubes, the controlled fabrication of biointerfacing colloidal motors, the effective control over the movement speeds, directions, and states of motors through integrating functional components, and the applications of motors in biomedical fields including drug targeted delivery, photothermal therapy, and biodetoxification.

Designing Micro- and Nanoswimmers for Specific Applications

ConspectusSelf-propelled colloids have emerged as a new class of active matter over the past decade. These are micrometer sized colloidal objects that transduce free energy from their surroundings and convert it to directed motion. The self-propelled colloids are in many ways, the synthetic analogues of biological self-propelled units such as algae or bacteria. Although they are propelled by very different mechanisms, biological swimmers are typically powered by flagellar motion and synthetic swimmers are driven by local chemical reactions, they share a number of common features with respect to swimming behavior. They exhibit run-and-tumble like behavior, are responsive to environmental stimuli, and can even chemically interact with nearby swimmers. An understanding of self-propelled colloids could help us in understanding the complex behaviors that emerge in populations of natural microswimmers. Self-propelled colloids also offer some advantages over natural microswimmers, since the surface properties, propulsion mechanisms, and particle geometry can all be easily modified to meet specific needs.From a more practical perspective, a number of applications, ranging from environmental remediation to targeted drug delivery, have been envisioned for these systems. These applications rely on the basic functionalities of self-propelled colloids: directional motion, sensing of the local environment, and the ability to respond to external signals. Owing to the vastly different nature of each of these applications, it becomes necessary to optimize the design choices in these colloids. There has been a significant effort to develop a range of synthetic self-propelled colloids to meet the specific conditions required for different processes. Tubular self-propelled colloids, for example, are ideal for decontamination processes, owing to their bubble propulsion mechanism, which enhances mixing in systems, but are incompatible with biological systems due to the toxic propulsion fuel and the generation of oxygen bubbles. Spherical swimmers serve as model systems to understand the fundamental aspects of the propulsion mechanism, collective behavior, response to external stimuli, etc. They are also typically the choice of shape at the nanoscale due to their ease of fabrication. More recently biohybrid swimmers have also been developed which attempt to retain the advantages of synthetic colloids while deriving their propulsion from biological swimmers such as sperm and bacteria, offering the means for biocompatible swimming. In this Account, we will summarize our effort and those of other groups, in the design and development of self-propelled colloids of different structural properties and powered by different propulsion mechanisms. We will also briefly address the applications that have been proposed and, to some extent, demonstrated for these swimmer designs.

Individual behaviors and dynamic self-assembly of active colloids

In recent years, there is mounting interesting in the study of active matters that self-propel by consuming energy and therefore lie beyond thermal equilibrium. Examples include fish schools, bird flocks, bacteria colonies, and tissues made of live cells, to name a few. Mobility of the individual components of these groups, coupled with communications among group members following some simple rules, often gives rise to fascinating and complex emergent behaviors. At the microscale, bacteria are often studied as model systems to understand how individual motion leads to collective behaviors. More recently, synthetic colloids that demonstrate autonomous motion and interesting dynamic assembly behaviors have been developed. Owing to their ease of fabrication, uniformity and functionalizability, these synthetic colloids have attracted much attention in extending our capability in the study of active matters. In this review, we highlight the recent development in the field of active colloids, which include both natural microorganisms as well as synthetic colloids. We begin with a short overview of the research on bacteria. When isolated, bacteria convert nutrients in the environment into directional motion randomized by Brownian motion, at a force scale around pN. A densely populated bacteria bath, however, demonstrate complicated collective behaviors such as swarming and the formation of biofilm. This is mostly attributed to hydrodynamic interaction and volume-exclusion effect at short time scales, while at longer times the chemicals excreted by bacteria start to significantly contribute to inter-bacteria communication. We then turn our attention to synthetic active colloids, especially their experimental aspects. A few popular synthetic systems are first described, focusing on their individual propulsion mechanisms. These include colloids propelled by self-generated gradients, such as self-electrophoresis, self-diffusiophoresis and self-thermophoresis. A few other popular mechanisms are also briefly introduced, including bubble-propulsion, and colloids driven by external fields (electromagnetic and ultrasound). Synthetic microswimmers when moving close by are found to communicate and interact with each other in a variety of ways, displaying collective behaviors ranging from clustering, schooling, and phase separation. We discuss the recent progress in the dynamic assembly of these active colloids, highlighting the complicated interplay among chemical gradients, electrostatic interactions, van der Waals forces and hydrodynamic interaction. It is common to find an active colloid that interacts with its neighbors by a combination of these mechanisms, especially for those driven by chemical gradients where chemical reactions, electric fields and hydrodynamic flows are intricately coupled. Although the behaviors of active colloids often bear striking resemblance to living microorganisms, the nature of their interactions reminds us of how fundamentally different these two types of swimmers are. Understanding their behaviors requires the collective wisdom of experimentalists, theorists and modeling experts. A well-defined model system that promises simple fabrication, ease of functionalization, tunability of parameters, and good reproducibility is also highly desired. At the end of this review, we present the possible directions for future studies in this field. These include: (1) The pursuit of new propulsion mechanisms for active colloids, particularly those that are biocompatible and/or suitable for high population density studies; (2) better understanding of the dynamic clustering effect of active colloids; (3) further exploration of behaviors of active colloids at high number densities; (4) the pursuit of appropriate thermodynamic parameters to describe active colloid systems.

Role of albumin, starches and gelatins versus crystalloids in volume resuscitation of critically ill patients.

The review focuses on fluid resuscitation of critically ill patients with either colloid or crystalloid solutions. In healthy patients, the volume expanding effect of colloids is greater than that of crystalloids. However, in critically ill patients, a similar amount of crystalloids and colloids is required for fluid resuscitation, suggesting a lower efficiency of colloids when capillary permeability is increased, and endothelial glycocalyx disrupted. Recent studies on synthetic colloids in surgical patients confirmed the increased risk of renal failure reported in large clinical trials performed in critically ill patients. Experimental studies suggest that albumin maintains plasma volume expansion efficiency even when the capillary permeability is impaired, and that extravasation of albumin to the interstitium is lower than that of hydroxyethyl starch. Fluid administration should be tailored to patient characteristics. Synthetic colloids should be avoided when possible, especially in patients at risk for kidney injury. In critically ill patients with suspected increased permeability, colloids may not be superior to crystalloids in expanding plasma volume. Albumin appears to be less harmful than synthetic colloids, although its beneficial effects need to be further investigated. The endothelial glycocalyx layer is the key structure finely regulating intravascular fluid distribution.

Intraoperative Hydroxyethyl Starch and its Effects on Different Fibrinogen Measurements.

Intravenous fluids with synthetic colloids such as hydroxyethyl starch (HES) are known to interfere with plasma fibrinogen concentration measurements. The aim of this study was to evaluate the effects of an HES solution on fibrinogen measurements in a clinical setting. The study was performed in patients who received at least 1 L of HES during intracranial tumor resection surgery. Blood samples were drawn before the start of surgery (baseline), after infusion of 1 L of HES, and at later time points. The fibrinogen concentration was measured using 3 different methods: (a) enzyme-linked immunosorbent assay (ELISA), (b) Clauss method with a photometric readout, and (c) Clauss method with an electromechanical readout. In addition, the fibrin-based clot quality was evaluated with the thromboelastometric FIBTEM test. Forty patients were enrolled, and 25 patients were included in the analysis. The fibrinogen concentrations at baseline were 2.2, 2.3, and 2.6 g/L and after 1 L of HES 1.6, 1.7, and 1.9 g/L as measured by ELISA, the photometric test, and the electromechanical test, respectively. The electromechanical Clauss test measured significantly higher concentrations at these time points. The relative decrease, however, was comparable between methods (31%, 29%, and 25%, respectively) but significantly lower than the 44% relative decrease with FIBTEM maximum clot firmness. Despite providing different fibrinogen concentration values at baseline, the relative decrease in fibrinogen concentration after HES infusion was comparable among the 3 tests. In contrast, fibrin-based clot quality was more affected than fibrinogen concentration tests by HES infusion.

How safe is gelatin? A systematic review and meta-analysis of gelatin-containing plasma expanders vs crystalloids and albumin

Gelatin is a widely used synthetic colloid resuscitation fluid. We undertook a systematic review and meta-analysis of adverse effects in randomized and nonrandomized studies comparing gelatin with crystalloid or albumin for treatment of hypovolemia. Multiple databases were searched systematically without language restrictions until August 2015. We assessed risk of bias of individual studies and certainty in evidence assessment by the Grading of Recommendations Assessment, Development, and Evaluation approach. Sixty studies were eligible, including 30 randomized controlled trials, 8 nonrandomized studies, and 22 animal studies. After gelatin administration, the risk ratios were 1.15 (95% confidence interval, 0.96-1.38) for mortality, 1.10 (0.86-1.41) for requiring allogeneic blood transfusion, 1.35 (0.58-3.14) for acute kidney injury, and 3.01 (1.27-7.14) for anaphylaxis. Well-performed nonrandomized trials found increased rates of hospital mortality and acute kidney injury or renal replacement therapy in the gelatin intervention periods. Between 17% and 31% of administered gelatin was taken up extravascularly. The mean crystalloid-to-colloid ratio was 1.4. Gelatin solutions increase the risk of anaphylaxis and may be harmful by increasing mortality, renal failure, and bleeding possibly due to extravascular uptake and coagulation impairment. Until well-designed randomized controlled trials show that gelatin is safe, we caution against the use of gelatins because cheaper and safer fluid alternatives are available.

Effect of intraoperative constant rate infusion of lidocaine on short-term survival of dogs with septic peritonitis: 75 cases (2007–2011)

To investigate whether intraoperative administration of a lidocaine infusion to dogs with septic peritonitis was associated with short-term (48 hours) survival after surgery. Retrospective case series. 75 dogs with septic peritonitis. Medical records of dogs with septic peritonitis that underwent laparotomy between January 2007 and December 2011 at the Royal Veterinary College were reviewed. Select variables during the preoperative, intraoperative, and postoperative periods and short-term survival after surgery were compared between dogs that received an opioid only (group O; n = 33) and dogs that received lidocaine (50 μg/kg/min [22.7 μg/kg/min], IV; group L; 42) in addition to an opioid during surgery. The proportion of dogs that survived for 48 hours after surgery was significantly greater for group L (35/42) than for group O (20/33). Intraoperative infusion of lidocaine increased the odds of short-term survival (OR, 8.77; 95% CI, 1.94 to 39.57). No significant differences were observed between the 2 treatment groups for variables assessed during the preoperative and postoperative periods. During the intraoperative period, more dogs in group L received an IV bolus of a synthetic colloid than did dogs in group O, but the number of IV boluses administered was not associated with short-term survival. Results indicated that IV infusion of lidocaine might improve the short-term survival of dogs with septic peritonitis. Prospective clinical trials are necessary to determine the efficacy of lidocaine as a supportive treatment for dogs with septic peritonitis.

Use of infusion solutions in critically ill: Literature review

The treatment of critically ill patients relies upon a series of pathophysiological disorders arising in the present critical condition. Loss of circulatory volume is one in a series of disturbed mechanisms that require proper correction. Causes of circulatory volume loss, hemodynamic instability and inadequate tissue perfusion are different: in sepsis and burns due to the higher capillary permeability, in trauma because of massive bleeding, etc. Infusion solutions, crystalloids and colloids have their good and bad qualities, and therefore must be seen as agents with specific indications, contraindications and the recommended doses. Assessment of stage of the disease, the amount and type of solutions to be applied has an influence on the further course of the disease. After review of randomized studies and meta-analysis, comparing crystalloids and colloids, moderate difference in their efficacy but significant difference in their safety is observed. The high concentration of chloride ion in solutions is of great clinical importance. The possibility of iatrogenic renal failure, metabolic acidosis and coagulopathy requires caution when using synthetic colloids and isotonic saline solutions. Physiologically 'balanced' crystalloid solutions may be standard in the treatment of critically ill patients, while the role of colloids, especially Hydroxyethylstarch, is still unreliable.

Clinical practice guide for the choice of perioperative volume-restoring fluid in adult patients undergoing non-cardiac surgery

The present clinical practice guide responds to the clinical questions about security in the choice of fluid (crystalloid, colloid or hydroxyethyl starch 130) in patients who require volume replacement during perioperative period of non-cardiac surgeries. From the evidence summary, recommendations were made following the GRADE methodology. In this population fluid therapy based on crystalloids is suggested (weak recommendation, low quality evidence). In the events where volume replacement is not reached with crystalloids, the use of synthetic colloids (hydroxyethyl starch 130 or modified fluid gelatin) is suggested instead of 5% albumin (weak recommendation, low quality evidence). The choice and dosage of the colloid should be based in the product characteristics, patient comorbidity and anesthesiologist's experience.

Making Food Protein Gels via an Arrested Spinodal Decomposition.

We report an investigation of the structural and dynamic properties of mixtures of food colloid casein micelles and low molecular weight poly(ethylene oxide). A combination of visual observations, confocal laser scanning microscopy, diffusing wave spectroscopy, and oscillatory shear rheometry is used to characterize the state diagram of the mixtures and describe the structural and dynamic properties of the resulting fluid and solid-like structures. We demonstrate the formation of gel-like structures through an arrested spinodal decomposition mechanism. We discuss our observations in view of previous experimental and theoretical studies with synthetic and food colloids, and comment on the potential of such a route toward gels for food processing.

Effects of different types of fluid resuscitation for hemorrhagic shock on splanchnic organ microcirculation and renal reactive oxygen species formation.

IntroductionFluid resuscitation is an indispensable procedure in the acute management of hemorrhagic shock for restoring tissue perfusion, particularly microcirculation in splanchnic organs. Resuscitation fluids include crystalloids, hypertonic saline (HTS), and synthetic colloids, and their selection affects the recovery of microcirculatory blood flow and reactive oxygen species (ROS) formation, which is often evident in the kidney, following reperfusion. In this study, the effects of acute resuscitation with 0.9 % saline (NS), 3 % HTS, 4 % succinylated gelatin (GEL), and 6 % hydroxyethyl starch (HES) 130/0.4 were compared in a hemorrhagic shock rat model to analyze restoration of microcirculation among various splanchnic organs and the gracilis muscle and reperfusion-induced renal ROS formation.MethodsA total of 96 male Wistar rats were subjected to sham operation (sham group), hemorrhagic shock (control group), and resuscitation with NS, HTS, GEL and HES. Two hours after resuscitation, changes in the mean arterial pressure (MAP), serum lactate level and the microcirculatory blood flow among various splanchnic organs, namely the liver, kidney, and intestine (mucosa, serosal muscular layer, and Peyer’s patch), and the gracilis muscle, were compared using laser speckle contrast imaging. Renal ROS formation after reperfusion was investigated using an enhanced in vivo chemiluminescence (CL) method.ResultsMicrocirculatory blood flow was less severely affected by hemorrhaging in the liver and gracilis muscle. Impairment of microcirculation in the kidney was restored in all resuscitation groups. Resuscitation in the NS group failed to restore intestinal microcirculation. Resuscitation in the HTS, GEL, and HES groups restored intestinal microcirculatory blood flow. By comparison, fluid resuscitation restored hemorrhagic shock-induced hypotension and decreased lactatemia in all resuscitation groups. Reperfusion-induced in vivo renal ROS formation was significantly higher in the GEL and HES groups than in the other groups.ConclusionAlthough fluid resuscitation with NS restored the MAP and decreased lactatemia following hemorrhagic shock, intestinal microcirculation was restored only by other volume expanders, namely 3 % HTS, GEL, and HES. However, reperfusion-induced renal ROS formation was significantly higher when synthetic colloids were used.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-015-1135-y) contains supplementary material, which is available to authorized users.

Intraoperative factors associated with delayed recovery of liver function after hepatectomy: analysis of 1969 living donors.

The safety of healthy living donors who are undergoing hepatic resection is a primary concern. We aimed to identify intraoperative anaesthetic and surgical factors associated with delayed recovery of liver function after hepatectomy in living donors. We retrospectively analysed 1969 living donors who underwent hepatectomy for living donor liver transplantation. Delayed recovery of hepatic function was defined by increases in international normalised ratio of prothrombin time and concomitant hyperbilirubinaemia on or after post-operative day 5. Univariate and multivariate logistic regression analyses were performed to determine the factors associated with delayed recovery of hepatic function after living donor hepatectomy. Delayed recovery of liver function after donor hepatectomy was observed in 213 (10.8%) donors. Univariate logistic regression analysis showed that sevoflurane anaesthesia, synthetic colloid, donor age, body mass index, fatty change and remnant liver volume were significant factors for prediction of delayed recovery of hepatic function. Multivariate logistic regression analysis showed that independent factors significantly associated with delayed recovery of liver function after donor hepatectomy were sevoflurane anaesthesia (odds ratio = 3.514, P < 0.001), synthetic colloid (odds ratio = 1.045, P = 0.033), donor age (odds ratio = 0.970, P = 0.003), female gender (odds ratio = 1.512, P = 0.014) and remnant liver volume (odds ratio = 0.963, P < 0.001). Anaesthesia with sevoflurane was an independent factor in predicting delayed recovery of hepatic function after donor hepatectomy. Although synthetic colloid may be associated with delayed recovery of hepatic function after donor hepatectomy, further study is required. These results can provide useful information on perioperative management of living liver donors.

Guía de práctica clínica para la elección del fluido de restauración volémica perioperatoria en los pacientes adultos intervenidos de cirugía no cardiaca

The present Clinical practice guide responds to the clinical questions about security in the choice of fluid (crystalloid, colloid or hydroxyethyl starch 130) in patients who require volume replacement during perioperative period of non-cardiac surgeries. From the evidence summary, recommendations were made following the GRADE methodology. In this population fluid therapy based on crystalloids is suggested (weak recommendation, low quality evidence). In the events where volume replacement is not reached with crystalloids, the use of synthetic colloids (hydroxyethyl starch 130 or modified fluid gelatin) is suggested instead of 5% albumin (weak recommendation, low quality evidence). The choice and dosage of the colloid should be based in the product characteristics, patient comorbidity and anesthesiologist's experience.

Synthetic Smectite Colloids: Characterization of Nanoparticles after Co-Precipitation in the Presence of Lanthanides and Tetravalent Elements (Zr, Th)

The magnesian smectite hectorite is a corrosion product frequently detected in nuclear waste glass alteration experiments. The structural incorporation of a single trivalent lanthanide was previously demonstrated. Hectorite was presently synthesized, for the first time, in the presence of several lanthanides (La, Eu, Yb) following a multi-step synthesis protocol. The smallest-sized particles (nanoparticles, NPs) were isolated by centrifugation and analyzed by asymmetrical flow field-flow fractionation (AsFlFFF) coupled to ICP-MS, in order to obtain information on the elemental composition and distribution as a function of the size. Nanoparticles can be separated from the bulk smectite phase. The particles are able to accommodate even the larger-sized lanthanides such as La, however, with lower efficiency. We, therefore, assume that the incorporation proceeds by substitution for octahedral Mg accompanied by a concomitant lattice strain that increases with the size of the lanthanides. The presence of a mixture does not seem to affect the incorporation extent of any specific element. Furthermore, syntheses were performed where in addition the tetravalent zirconium or thorium elements were admixed, as this oxidation state may prevail for many actinide ions in a nuclear waste repository. The results show that they can be incorporated as well.

Are all fluids bad for the kidney?

To describe the harmful effects of intravenous fluids on kidney structure and function and summarize recent comparisons between different fluids and their effect on kidney outcome. Administration of intravenous fluids may contribute to the development and sustention of acute kidney injury. In excess, fluids cause kidney interstitial edema and venous congestion, which prevents renal blood flow and glomerular filtration rate. In contrast to balanced crystalloids, chloride-rich solutions impair renal blood flow via autoregulatory mechanisms. Synthetic colloids, such as hydroxyethyl starches, gelatins, and dextrans are potentially nephrotoxic because they can cause osmotic nephrosis, which, in susceptible patients, might precede permanent kidney damage. Albumin solutions appear well tolerated to use in septic patients, although their renal efficacy over balanced crystalloids is not established. In contrast, administration of albumin solutions to patients with decompensated liver failure effectively prevents and ameliorates hepatorenal syndrome. Being nephrotoxic, synthetic colloids should be avoided in patients with reduced renal reserve, such as in critically ill patients and in patients with preexisting renal dysfunction. Suggested adverse effects with chloride-rich solutions need confirmation from ongoing trials. Albumin solutions are well tolerated in patients with sepsis and/or liver failure and improve outcomes in the latter.