Review

Authors: P Guilabert, G Usúa, N Martín...

Since 1968, when Baxter and Shires developed the Parkland formula, little progress has been made in the field of fluid therapy for burn resuscitation, despite advances in haemodynamic monitoring, establishment of the 'goal-directed therapy' concept, and the development of new colloid and crystalloid solutions. Burn patients receive a larger amount of fluids in the first hours than any other trauma patients. Initial resuscitation is based on crystalloids because of the increased capillary permeability occurring during the first 24 h. After that time, some colloids, but not all, are accepted. Since the emergence of the Pharmacovigilance Risk Assessment Committee alert from the European Medicines Agency concerning hydroxyethyl starches, solutions containing this component are not recommended for burns. But the question is: what do we really know about fluid resuscitation in burns? To provide an answer, we carried out a non-systematic review to clarify how to quantify the amount of fluids needed, what the current evidence says about the available solutions, and which solution is the most appropriate for burn patients based on the available knowledge.

Topics: Burns; Colloids; Crystalloid Solutions; Fluid Therapy; Humans; Isotonic Solutions

PubMed: 27543523
DOI: 10.1093/bja/aew266

Meta-Analysis

Authors: Sharon R Lewis, Michael W Pritchard, David Jw Evans...

BACKGROUND

Critically ill people may lose fluid because of serious conditions, infections (e.g. sepsis), trauma, or burns, and need additional fluids urgently to prevent dehydration or kidney failure. Colloid or crystalloid solutions may be used for this purpose. Crystalloids have small molecules, are cheap, easy to use, and provide immediate fluid resuscitation, but may increase oedema. Colloids have larger molecules, cost more, and may provide swifter volume expansion in the intravascular space, but may induce allergic reactions, blood clotting disorders, and kidney failure. This is an update of a Cochrane Review last published in 2013.

OBJECTIVES

To assess the effect of using colloids versus crystalloids in critically ill people requiring fluid volume replacement on mortality, need for blood transfusion or renal replacement therapy (RRT), and adverse events (specifically: allergic reactions, itching, rashes).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and two other databases on 23 February 2018. We also searched clinical trials registers.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs of critically ill people who required fluid volume replacement in hospital or emergency out-of-hospital settings. Participants had trauma, burns, or medical conditions such as sepsis. We excluded neonates, elective surgery and caesarean section. We compared a colloid (suspended in any crystalloid solution) versus a crystalloid (isotonic or hypertonic).

DATA COLLECTION AND ANALYSIS

Independently, two review authors assessed studies for inclusion, extracted data, assessed risk of bias, and synthesised findings. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 69 studies (65 RCTs, 4 quasi-RCTs) with 30,020 participants. Twenty-eight studied starch solutions, 20 dextrans, seven gelatins, and 22 albumin or fresh frozen plasma (FFP); each type of colloid was compared to crystalloids.Participants had a range of conditions typical of critical illness. Ten studies were in out-of-hospital settings. We noted risk of selection bias in some studies, and, as most studies were not prospectively registered, risk of selective outcome reporting. Fourteen studies included participants in the crystalloid group who received or may have received colloids, which might have influenced results.We compared four types of colloid (i.e. starches; dextrans; gelatins; and albumin or FFP) versus crystalloids.Starches versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using starches or crystalloids in mortality at: end of follow-up (risk ratio (RR) 0.97, 95% confidence interval (CI) 0.86 to 1.09; 11,177 participants; 24 studies); within 90 days (RR 1.01, 95% CI 0.90 to 1.14; 10,415 participants; 15 studies); or within 30 days (RR 0.99, 95% CI 0.90 to 1.09; 10,135 participants; 11 studies).We found moderate-certainty evidence that starches probably slightly increase the need for blood transfusion (RR 1.19, 95% CI 1.02 to 1.39; 1917 participants; 8 studies), and RRT (RR 1.30, 95% CI 1.14 to 1.48; 8527 participants; 9 studies). Very low-certainty evidence means we are uncertain whether either fluid affected adverse events: we found little or no difference in allergic reactions (RR 2.59, 95% CI 0.27 to 24.91; 7757 participants; 3 studies), fewer incidences of itching with crystalloids (RR 1.38, 95% CI 1.05 to 1.82; 6946 participants; 2 studies), and fewer incidences of rashes with crystalloids (RR 1.61, 95% CI 0.90 to 2.89; 7007 participants; 2 studies).Dextrans versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using dextrans or crystalloids in mortality at: end of follow-up (RR 0.99, 95% CI 0.88 to 1.11; 4736 participants; 19 studies); or within 90 days or 30 days (RR 0.99, 95% CI 0.87 to 1.12; 3353 participants; 10 studies). We are uncertain whether dextrans or crystalloids reduce the need for blood transfusion, as we found little or no difference in blood transfusions (RR 0.92, 95% CI 0.77 to 1.10; 1272 participants, 3 studies; very low-certainty evidence). We found little or no difference in allergic reactions (RR 6.00, 95% CI 0.25 to 144.93; 739 participants; 4 studies; very low-certainty evidence). No studies measured RRT.Gelatins versus crystalloidsWe found low-certainty evidence that there may be little or no difference between gelatins or crystalloids in mortality: at end of follow-up (RR 0.89, 95% CI 0.74 to 1.08; 1698 participants; 6 studies); within 90 days (RR 0.89, 95% CI 0.73 to 1.09; 1388 participants; 1 study); or within 30 days (RR 0.92, 95% CI 0.74 to 1.16; 1388 participants; 1 study). Evidence for blood transfusion was very low certainty (3 studies), with a low event rate or data not reported by intervention. Data for RRT were not reported separately for gelatins (1 study). We found little or no difference between groups in allergic reactions (very low-certainty evidence).Albumin or FFP versus crystalloidsWe found moderate-certainty evidence that there is probably little or no difference between using albumin or FFP or using crystalloids in mortality at: end of follow-up (RR 0.98, 95% CI 0.92 to 1.06; 13,047 participants; 20 studies); within 90 days (RR 0.98, 95% CI 0.92 to 1.04; 12,492 participants; 10 studies); or within 30 days (RR 0.99, 95% CI 0.93 to 1.06; 12,506 participants; 10 studies). We are uncertain whether either fluid type reduces need for blood transfusion (RR 1.31, 95% CI 0.95 to 1.80; 290 participants; 3 studies; very low-certainty evidence). Using albumin or FFP versus crystalloids may make little or no difference to the need for RRT (RR 1.11, 95% CI 0.96 to 1.27; 3028 participants; 2 studies; very low-certainty evidence), or in allergic reactions (RR 0.75, 95% CI 0.17 to 3.33; 2097 participants, 1 study; very low-certainty evidence).

AUTHORS' CONCLUSIONS

Using starches, dextrans, albumin or FFP (moderate-certainty evidence), or gelatins (low-certainty evidence), versus crystalloids probably makes little or no difference to mortality. Starches probably slightly increase the need for blood transfusion and RRT (moderate-certainty evidence), and albumin or FFP may make little or no difference to the need for renal replacement therapy (low-certainty evidence). Evidence for blood transfusions for dextrans, and albumin or FFP, is uncertain. Similarly, evidence for adverse events is uncertain. Certainty of evidence may improve with inclusion of three ongoing studies and seven studies awaiting classification, in future updates.

Topics: Colloids; Critical Illness; Crystalloid Solutions; Fluid Therapy; Humans; Isotonic Solutions; Plasma Substitutes; Randomized Controlled Trials as Topic; Rehydration Solutions; Renal Replacement Therapy

PubMed: 30073665
DOI: 10.1002/14651858.CD000567.pub7

Authors: Nadine Dyballa, Sabine Metzger

Coomassie Brilliant Blue (CBB) is a dye commonly used for the visualization of proteins separated by SDS-PAGE, offering a simple staining procedure and high quantitation. Furthermore, it is completely compatible with mass spectrometric protein identification. But despite these advantages, CBB is regarded to be less sensitive than silver or fluorescence stainings and therefore rarely used for the detection of proteins in analytical gel-based proteomic approaches. Several improvements of the original Coomassie protocol(1) have been made to increase the sensitivity of CBB. Two major modifications were introduced to enhance the detection of low-abundant proteins by converting the dye molecules into colloidal particles: In 1988, Neuhoff and colleagues applied 20% methanol and higher concentrations of ammonium sulfate into the CBB G-250 based staining solution(2), and in 2004 Candiano et al. established Blue Silver using CBB G-250 with phosphoric acid in the presence of ammonium sulfate and methanol(3). Nevertheless, all these modifications just allow a detection of approximately 10 ng protein. A widely fameless protocol for colloidal Coomassie staining was published by Kang et al. in 2002 where they modified Neuhoff's colloidal CBB staining protocol regarding the complexing substances. Instead of ammonium sulfate they used aluminum sulfate and methanol was replaced by the less toxic ethanol(4). The novel aluminum-based staining in Kang's study showed superior sensitivity that detects as low as 1 ng/band (phosphorylase b) with little sensitivity variation depending on proteins. Here, we demonstrate application of Kang's protocol for fast and sensitive colloidal Coomassie staining of proteins in analytical purposes. We will illustrate the quick and easy protocol using two-dimensional gels routinely performed in our working group.

Topics: Acrylic Resins; Colloids; Electrophoresis, Gel, Two-Dimensional; Indicators and Reagents; Proteins; Rosaniline Dyes; Sensitivity and Specificity; Staining and Labeling

PubMed: 19684561
DOI: 10.3791/1431

Review

Authors: J Boldt, S Suttner

Adequate restoration of intravascular volume remains an important therapeutic manoeuvre in managing the surgical, medical and the critically ill intensive care patient. Definition of the ideal volume replacement strategy still remains one of the burning problems. The choice between colloid and crystalloid solutions continues to generate controversy. The highly controversial crystalloid/colloid dispute has been enlarged to a colloid/colloid debate because aside of the natural colloid albumin several non-protein (synthetic) colloids are available as plasma substitutes (e.g. dextrans, gelatins, hydroxyethyl starch [HES] solutions). Due to their varying physico-chemical properties, these solutions widely differ with regard to their pharmacokinetic and pharmacodynamic properties as well as to their hemodynamic efficacy and side-effects. HES is the most intensively studied plasma substitute. The different HES preparations are defined by concentration, molar substitution (MS), mean molecular weight (MW), and the C2/C6 ratio of substitution. Two new HES specification, a third-generation HES with a lower Mw and a lower MS (6% HES 130/0.4) than all other HES preparation and a first-generation HES prepared in a balanced solution, may be promising by improving the therapy of the hypovolemic patient. Albumin cannot be recommended for correction of hypovolemia because of ist extreme costs and because it can easily be replaced by other no-protein colloids. Dextrans should also not be used any more due to the negative effects on coagulation and its high anaphylactic potency. The historical crystalloid/colloid controversy has been focused primarily on outcome. There is increasing evidence that outcome (mortality) is not the correct measure when assessing the ideal volume replacement strategy. New concepts about critical care such as organ perfusion and organ function, the role of inflammation, immunological aspects, and wound healing may change this point of view. Volume replacement has been hitherto often based on art, dogma and personal beliefs. Further well-performed studies in this area will help more to shed new light on the ideal volume replacement strategy of the hypovolemic patient than more meta-analyses that are pooling old-to-very old studies to solve this problem.

Topics: Blood Volume; Colloids; Critical Care; Crystalloid Solutions; Fluid Therapy; Humans; Isotonic Solutions; Plasma Substitutes

PubMed: 16288182
DOI: No ID Found

Review

Authors: Robert G Hahn

Guidelines for infusion fluid therapy rarely take into account that adverse effects occur in a dose-dependent fashion. Adverse effects of crystalloid fluids are related to their preferential distribution to the interstitium of the subcutis, the gut, and the lungs. The gastrointestinal recovery time is prolonged by 2 days when more than 2 litres is administered. Infusion of 6-7 litres during open abdominal surgery results in poor wound healing, pulmonary oedema, and pneumonia. There is also a risk of fatal postoperative pulmonary oedema that might develop several days after the surgery. Even larger amounts cause organ dysfunction by breaking up the interstitial matrix and allowing the formation of lacunae of fluid in the skin and central organs, such as the heart. Adverse effects of colloid fluids include anaphylactic reactions, which occur in 1 out of 500 infusions. The possibility that hydroxyethyl starch causes kidney injury in patients other than those with sepsis is still unclear. For both crystalloid and colloid fluids, coagulation becomes impaired when the induced haemodilution has reached 40%. Coagulopathy is aggravated by co-existing hypothermia. Although oedema can occur from both crystalloid and colloid fluids, these differ in pathophysiology. To balance fluid-induced adverse effects, this review suggests that a colloid fluid is indicated when the infused crystalloid volume exceeds 3-4 litres, plasma volume support is still needed, and the transfusion of blood products is not yet indicated.

Topics: Anaphylaxis; Colloids; Crystalloid Solutions; Dose-Response Relationship, Drug; Fluid Therapy; Humans; Hydroxyethyl Starch Derivatives; Isotonic Solutions; Plasma Volume; Postoperative Complications; Practice Guidelines as Topic; Tissue Distribution

PubMed: 28953310
DOI: 10.5603/AIT.a2017.0045

Comparative Study Review

Authors: L E Ratner, G W Smith

The surgeon should be cognizant of both the intraoperative and postoperative consequences of intraoperative fluid administration. Optimal fluid management should take into consideration the patient's overall condition and should not be based solely on the cardiovascular response to volume loading. The selection of a particular fluid for resuscitation solution should be tailored to the patient's individual situation. No single fluid preparation will be appropriate for all clinical situations. Crystalloids, colloids, and hypertonic saline solutions have all been shown to be effective in restoring intravascular volume. Each has its own relative advantages and disadvantages and will be appropriate in differing situations. Colloid preparations should not be avoided for fear of inducing pulmonary edema, and the use of hypertonic solutions should not be precluded by fear of potential metabolic complications. The judicious use of both hypertonic solutions and colloids is safe. For the vast majority of routine surgical cases, where the patient is hemodynamically stable and postoperative fluid overloading is not a significant problem, isotonic crystalloids such as lactated Ringer's are both sufficient and cost effective.

Topics: Colloids; Crystalloid Solutions; Fluid Therapy; Humans; Intraoperative Care; Intraoperative Complications; Isotonic Solutions; Plasma Substitutes; Saline Solution, Hypertonic; Solutions

PubMed: 8456354
DOI: 10.1016/s0039-6109(16)45978-5

Review

Authors: T J Mitchison

Crowding of the subcellular environment by macromolecules is thought to promote protein aggregation and phase separation. A challenge is how to parameterize the degree of crowding of the cell interior or artificial solutions that is relevant to these reactions. Here I review colloid osmotic pressure as a crowding metric. This pressure is generated by solutions of macromolecules in contact with pores that are permeable to water and ions but not macromolecules. It generates depletion forces that push macromolecules together in crowded solutions and thus promotes aggregation and phase separation. I discuss measurements of colloid osmotic pressure inside cells using the nucleus, the cytoplasmic gel, and fluorescence resonant energy transfer (FRET) biosensors as osmometers, which return a range of values from 1 to 20 kPa. I argue for a low value, 1-2 kPa, in frog eggs and perhaps more generally. This value is close to the linear range on concentration-pressure curves and is thus not crowded from an osmotic perspective. I discuss the implications of a low crowding pressure inside cells for phase separation biology, buffer design, and proteome evolution. I also discuss a pressure-tension model for nuclear shape, where colloid osmotic pressure generated by nuclear protein import inflates the nucleus.

Topics: Animals; Colloids; Hydrodynamics; Macromolecular Substances; Models, Biological; Osmosis; Subcellular Fractions

PubMed: 30640588
DOI: 10.1091/mbc.E18-09-0549

Authors: Maiko Obana, Bradley R Silverman, David A Tirrell...

Programmable colloidal assembly enables the creation of mesoscale materials in a bottom-up manner. Although DNA oligonucleotides have been used extensively as the programmable units in this paradigm, proteins, which exhibit more diverse modes of association and function, have not been widely used to direct colloidal assembly. Here we use protein-protein interactions to drive controlled aggregation of polystyrene microparticles, either through reversible coiled-coil interactions or through intermolecular isopeptide linkages. The sizes of the resulting aggregates are tunable and can be controlled by the concentration of immobilized surface proteins. Moreover, particles coated with different protein pairs undergo orthogonal assembly. We demonstrate that aggregates formed by association of coiled-coil proteins, in contrast to those linked by isopeptide bonds, are dispersed by treatment with chemical denaturants or soluble competing proteins. Finally, we show that protein-protein interactions can be used to assemble complex core-shell aggregates. This work illustrates a versatile strategy for engineering colloidal systems for use in materials science and biotechnology.

Topics: Bacterial Proteins; Colloids; Dimerization; Immobilized Proteins; Models, Molecular; Particle Size; Polystyrenes; Protein Interaction Maps; Streptococcus pyogenes

PubMed: 28898068
DOI: 10.1021/jacs.7b07798

Authors: Yuanwei Li, Wenjie Zhou, Ibrahim Tanriover...

Although tremendous advances have been made in preparing porous crystals from molecular precursors, there are no general ways of designing and making topologically diversified porous colloidal crystals over the 10-1,000 nm length scale. Control over porosity in this size range would enable the tailoring of molecular absorption and storage, separation, chemical sensing, catalytic and optical properties of such materials. Here, a universal approach for synthesizing metallic open-channel superlattices with pores of 10 to 1,000 nm from DNA-modified hollow colloidal nanoparticles (NPs) is reported. By tuning hollow NP geometry and DNA design, one can adjust crystal pore geometry (pore size and shape) and channel topology (the way in which pores are interconnected). The assembly of hollow NPs is driven by edge-to-edge rather than face-to-face DNA-DNA interactions. Two new design rules describing this assembly regime emerge from these studies and are then used to synthesize 12 open-channel superlattices with control over crystal symmetry, channel geometry and topology. The open channels can be selectively occupied by guests of the appropriate size and that are modified with complementary DNA (for example, Au NPs).

Topics: DNA; Gold; Nanoparticles; Particle Size; Porosity; Colloids; Crystallization

PubMed: 36289344
DOI: 10.1038/s41586-022-05291-y

Review

Authors: Kyle J M Bishop, Sibani Lisa Biswal, Bhuvnesh Bharti...

Active colloids use energy input at the particle level to propel persistent motion and direct dynamic assemblies. We consider three types of colloids animated by chemical reactions, time-varying magnetic fields, and electric currents. For each type, we review the basic propulsion mechanisms at the particle level and discuss their consequences for collective behaviors in particle ensembles. These microscopic systems provide useful experimental models of nonequilibrium many-body physics in which dissipative currents break time-reversal symmetry. Freed from the constraints of thermodynamic equilibrium, active colloids assemble to form materials that move, reconfigure, heal, and adapt. Colloidal machines based on engineered particles and their assemblies provide a basis for mobile robots with increasing levels of autonomy. This review provides a conceptual framework for understanding and applying active colloids to create material systems that mimic the functions of living matter. We highlight opportunities for chemical engineers to contribute to this growing field.

Topics: Physical Phenomena; Models, Theoretical; Motion; Thermodynamics; Colloids

PubMed: 36930877
DOI: 10.1146/annurev-chembioeng-101121-084939