Plasma Colloid Osmotic Pressure Research Articles

Fundamental equations and hypotheses governing glomerular hemodynamics.

The glomerular filtration rate (GFR) is the outcome of glomerular hemodynamics, influenced by a series of parameters: renal plasma flow, resistances of afferent arterioles and efferent arterioles (EAs), hydrostatic pressures in the glomerular capillary and Bowman's capsule, and plasma colloid osmotic pressure in the glomerular capillary. Although mathematical models have been proposed to predict the GFR at both the single-nephron level and the two-kidney system level using these parameters, mathematical equations governing glomerular filtration have not been well-established because of two major problems. First, the two-kidney system-level models are simply extended from the equations at the single-nephron level, which is inappropriate in epistemology and methodology. Second, the role of EAs in maintaining the normal GFR is underappreciated. In this article, these two problems are concretely elaborated, which collectively shows the need for a shift in epistemology toward a more holistic and evolving way of thinking, as reflected in the concept of the complex adaptive system (CAS). Then, we illustrate eight fundamental mathematical equations and four hypotheses governing glomerular hemodynamics at both the single-nephron and two-kidney levels as the theoretical foundation of glomerular hemodynamics. This illustration takes two steps. The first step is to modify the existing equations in the literature and establish a new equation within the conventional paradigm of epistemology. The second step is to formulate four hypotheses through logical reasoning from the perspective of the CAS (beyond the conventional paradigm). Finally, we apply the new equation and hypotheses to comprehensively analyze glomerular hemodynamics under different conditions and predict the GFR. By doing so, some concrete issues are eliminated. Unresolved issues are discussed from the perspective of the CAS and a desinger's view. In summary, this article advances the theoretical study of glomerular dynamics by 1) clarifying the necessity of shifting to the CAS paradigm; 2) adding new knowledge/insights into the significant role of EAs in maintaining the normal GFR; 3) bridging the significant gap between research findings and physiology education; and 4) establishing a new and advanced foundation for physiology education.

Plasma colloid osmotic pressure in preeclampsia. Review of the Mexican literature 1997-2018

Plasma colloid osmotic pressure in preeclampsia. Review of the Mexican literature 1997-2018

Recruitment of efferent lymph during infusion of 20% albumin.

Intravenous infusion of hyper-oncotic 20% albumin expands the plasma volume by approximately twice the infused volume. We investigated whether the recruited fluid stems from accelerated flow of efferent lymph, which would add protein to the plasma, or from reversed transcapillary solvent filtration, where the solvent is expected to be low in protein. We analyzed data from 27 intravenous infusions of 20% albumin (3mL/kg; approximately 200mL) over 30min given to 27 volunteers and patients. Twelve of the volunteers were also given a 5% solution and served as controls. The pattern of blood hemoglobin, colloid osmotic pressure, and the plasma concentrations of two immunoglobulins (IgG and IgM) were studied over 5h. A decrease of the difference between the plasma colloid osmotic pressure and plasma albumin occurred during the infusions and was almost four times greater for 5% albumin than for 20% albumin at 40min (P<0.0036), which indicates that non-albumin protein enriched the plasma when 20% was infused. Moreover, the difference between the infusion-derived dilution of the blood plasma based on hemoglobin and the two immunoglobulins amounted to -1.9% (-6 to +0.2) for 20% albumin and to -4.4% (25th-75th percentile range-8.5 to +0.2) during experiments with 5% albumin (P<0.001). This supports that the plasma was enriched by immunoglobulins, probably via the lymph, when 20% was infused. Between half and two-thirds of the extravascular fluid that was recruited during infusion of 20% albumin in humans consisted of protein-containing fluid consistent with efferent lymph.

Effect of Exogenous Albumin Replacement on Plasma Colloid Osmotic Pressure in Severe Preeclampsia: A Case-control Study

Background: In preeclampsia, hypoalbuminemia reduces plasma colloid osmotic pressure (PCOP) and favors capillary leakage. Replacement with exogenous albumin is a therapeutic alternative.&#x0D; Objective: to determine the effect of exogenous albumin replacement on PCOP in patients with severe preeclampsia (SP).&#x0D; Methods: A case-control study was carried out in 76 pregnant patients with SP from the Intensive Care Unit (ICU). The case group (n=38) received 0.9% saline solution 1000 ml every 8 hours and 25% albumin 50 ml every 8 hours and the control group (n=38) only received 0.9% saline solution 1000 ml every 8 hours. Plasma albumin concentrations, PCOP, hemodynamic and laboratory data from admission (baseline measurement) vs discharge from the ICU (final measurement) of both groups were compared.&#x0D; Statistical Analysis: the data was analyzed with descriptive statistics, paired Student's t-test and Pearson's correlation coefficient with the statistical program SPSS® version 20. The p value &lt;0.05 was significant.&#x0D; Results: A significant decrease in plasma albumin was found (case group 2.72±0.44 vs 2.45±0.48 g/dL, p=0.0141; control group 3.06±0.33 vs 2.58±0.29 g/dL, p=0.0431). PCOP was also significantly reduced (case group 18.44±2.92 vs 16.82±2.70 mmHg, p=0.0210; control group 20.38±2.28 vs 17.46±1.96 mmHg, p=0.0763). The group of cases showed an increase in uresis (p=0.0326), but without changes in central venous pressure (p=0.3246) and serum creatinine (p=0.9515). With this evidence the recommendation is that its use in patients with preeclampsia should be reserved for the experience of the medical team.&#x0D; Conclusion: Exogenous albumin replacement therapy did not correct the PCOP values or the blood albumin concentration.

Abstract #1405611: A Case Regarding Severe Hypothyroidism Which Complicated to De Novo Nephrotic Syndrome (Minimal Change Disease)

Hypothyroidism is a condition of an under-reactive thyroid. More prevalent in women, 10% exhibit some degree of thyroid insufficiency. It has numerous metabolic effects and may have an impact on renal physiology and worsening kidney function. Hypothyroidism was cited in certain case studies as a contributing factor to minimal change disease, which we will be highlighting here. We report a case of an 82-year-old female with PMH of graves’ disease status post left thyroidectomy in 2009 and was started on Levothyroxine, reported non-compliance, presented to the emergency department with a complaint of generalized edema mostly lower extremities that is progressively worsening over 2 weeks along with foamy urine. Unremarkable physical exam except for 2+ lower extremity pitting edema. On lab, high thyroid stimulating hormone (TSH) was 65.2 ulU/ml, normal Free Thyroxin (FT4) and low Free Triiodothyronine (FT3) 0.4 pg/ml, Serum Creatinine is 4.35 mg/dl, Urinalysis shows >500 protein, urine protein/Cr was 3, hypoalbuminemia and hyperlipidemia were present. A Glomerulopathy workup was initiated. She was admitted for further testing. Autoimmune kidney diseases were ruled out and a renal biopsy was performed, the specimen revealed Minimal change disease. She was started on Prednisone 60 mg daily and Levothyroxine 125 mcg. Three weeks later, patient showed a good response to therapy with an improvement of symptoms and repeated creatinine was 3.8. Hypothyroidism can be caused by partial or total thyroidectomy. As a highly lipophilic substance, Thyroxine binds to receptors that are expressed in cells all over the body to exhibit its physiological action. In patients with thyroidectomy, exogenous levothyroxine is the thyroid hormone supply to the body. Not having enough supply, can alter kidney function by affecting vascular resistance, re-absorptive process, and renal blood flow. It can also affect the RAAS system, beta-adrenergic receptors, and dopaminergic activation of the renal tubular cells. Gradual worsening of kidney function leads to an increase in the loss of free and bound thyroid hormones and eventually increases thyroxine requirement. GFR is reversibly reduced (by about 40%) in more than 55% of adults with hypothyroidism. Thyroxine treatment is effective by reducing edema, capillary permeability of albumin, and plasma colloid osmotic pressure. Proteinuria can sometimes be reversible by prompt initiation of thyroxine treatment. Also, the severity of symptoms plays a role in recovery. More research is needed to determine the relationship between hypothyroidism and nephrotic syndrome as only a few isolated occurrences were reported in the literature.

Hypothesis: Drainage of the peripheral tissue edema by the hyperbaric oxygen therapy because of hyperoxygenation that constricts arterioles and alters the downstream capillary fluid traffic in affected tissues.

Hyperbaric oxygen (HBO) therapy still lacks proper interpretations of its many actions. This hypothesis is based on reports of temporarily elevated peripheral vascular resistance (PVR) during HBO sessions. Besides that, during HBO sessions, hyperoxygenated tissues can reduce their perfusion so much that CO2 can accumulate in them. Tissue perfusion depends on vascular innervation and on the balance between systemic constrictors and local dilators. During an HBO session, increased tissue oxygen levels suppress dilatory mechanisms. Tissue hyperoxygenation increases PVR, suggesting that the HBO action on an edematous tissue may be caused by an oxygen-induced disbalance among Starling capillary forces. The presented hypothesis is that oxygen-caused arteriolar constriction reduces the hydrostatic pressure in downstream capillaries. Thus, more tissue fluid is absorbed in vascular capillaries, under the condition that the plasma colloid osmotic pressure remains unaltered during the HBO session. Among several known mechanisms behind the HBO actions, the vasoconstriction has been listed as a therapeutic modality for the reduction of the tissue edema, for a crush injury, for burns (in an acute phase), and for the compartment syndrome. The Bell's palsy is among often listed indications for the HBO treatment, although evidence is poor and reports of randomized trials are scarce.

Effect of goal-directed fluid therapy based on plasma colloid osmotic pressure on the postoperative pulmonary complications of older patients undergoing major abdominal surgery

BackgroundAs an important component of accelerated rehabilitation surgery, goal-directed fluid therapy (GDT) is one of the optimized fluid therapy strategies and is closely related to perioperative complications and mortality. This article aimed to study the effect of combining plasma colloid osmotic pressure (COP) with stroke volume variation (SVV) as a target for intraoperative GDT for postoperative pulmonary complications in older patients undergoing major abdominal surgery.MethodsIn this study, older patients (n = 100) undergoing radical resection of gastroenteric tumors were randomized to three groups: Group C (n1 = 31) received a conventional infusion regimen, Group S1 (n2 = 34) received GDT based on SVV, and Group S2 (n3 = 35) received GDT based on SVV and COP. The results were recorded, including the lung injury score (LIS); PaO2/FiO2 ratio; lactic acid value at the times of beginning (T0) and 1 h (T1), 2 h (T2), and 3 h (T3) after liquid infusion in the operation room; the total liquid infusion volume; infusion volumes of crystalline and colloidal liquids; urine production rate; pulmonary complications 7 days after surgery; and the severity grading of postoperative pulmonary complications.ResultsThe patients in the S2 group had fewer postoperative pulmonary complications than those in the C group (P < 0.05) and the proportion of pulmonary complications of grade 1 and higher than grade 2 in S2 group was significantly lower than that in C group (P <0.05); the patients in the S2 group had a higher PaO2/FiO2 ratio than those in the C group (P < 0.05), lower LIS than those in the S1 and C groups (P < 0.05), less total liquid infusion than those in the C group (P < 0.05), and more colloidal fluid infusion than those in the S1 and C groups (P < 0.05).ConclusionThe findings of our study show that intraoperative GDT based on COP and SVV can reduce the incidence of pulmonary complications and conducive to shortening the hospital stay in older patients after gastrointestinal surgery.Trial registrationChinese Clinical Trial. no. ChiCTR2100045671. Registry at www.chictr.org.cn on April 20, 2021.

Factors Regulating Fluid Restitution and Plasma Volume Reduction over the Course of Hemodialysis.

Over the course of hemodialysis, fluid and protein are restituted from the tissue compartment to the circulation compartment through the endothelia. Our previous model analysis on fluid and protein transport during hemodialysis is expanded to account for changes occurring in the tissue. The measured initial and end plasma protein concentration (PPC, Cp and Cp') for six hemodialysis studies are analyzed by this expanded model. The computation results indicate that the total driving pressure to restitute fluid from the tissue to the circulation ranges from 5.4 to 20.3 mmHg. The analysis identifies that the increase in plasma colloidal osmotic pressure (COP) contributes 78 ± 6% of the total driving pressure, the decrease in microvascular blood pressure 32 ± 4%, the increase in the COP of interstitial fluid -6 ± 3%, and the decrease in interstitial fluid pressure -5 ± 2%. Let this ratio (Cp' - Cp)/Cp' be termed the PPC increment. The six HDs can be divided into three groups which are to have these PPC increments 25.7%, 14.5 ± 2.6(SD)% and 8.3%. It is calculated that their correspondent filtration coefficients are 0.43, 1.29 ± 0.28 and 5.93 mL/min/mmHg and the relative reductions in plasma volume (RRPV) -22.1%, -13.1 ± 6% and -9.4%. The large variations in PPC increments and RRPV show the filtration coefficient is a key factor to regulate the hemodialysis process.

Kinetics of 5% and 20% albumin: A controlled crossover trial in volunteers.

BackgroundAlbumin for intravenous infusion is marketed in two concentrations, 20% and 5%, but how they compare with regard to plasma volume expansion over time is unclear.MethodsIn a prospective crossover study, 12 volunteers received 3 ml kg−1 of 20% albumin and, on another occasion, 12 ml kg−1 of 5% albumin over 30 min. Hence, equivalent amounts of albumin were given. Blood was collected on 15 occasions over 6 h. Mass balance and volume kinetics were used to estimate the plasma volume expansion and the capillary leakage of albumin and fluid based on measurements of blood hemoglobin, plasma albumin, and the colloid osmotic pressure.ResultsThe greatest plasma volume expansion was 16.0 ± 6.4% (mean ± SD) with 20% albumin and 19.0 ± 5.2% with 5% albumin (p < .03). The volume expansion with 20% albumin corresponded to twice the infused volume. One third of the 5% albumin volume quickly leaked out of the plasma, probably because of the higher colloid osmotic pressure of the volunteer plasma (mean, 24.5 mmHg) than the albumin solution (19.1 mmHg). At 6 h, the capillary leakage amounted to 42 ± 15% and 47 ± 11% of the administered albumin with the 20% and 5% preparations, respectively (p = .28). The corresponding urine outputs were 547 (316–780) ml and 687 (626–1080) ml (median and interquartile range; p = .24).ConclusionThe most important difference between the fluids was a dehydrating effect of 20% albumin when the same albumin mass was administered.

Development and Validation of a Nomogram Incorporating Colloid Osmotic Pressure for Predicting Mortality in Critically Ill Neurological Patients.

Backgrounds: The plasma colloid osmotic pressure (COP) values for predicting mortality are not well-estimated. A user-friendly nomogram could predict mortality by incorporating clinical factors and scoring systems to facilitate physicians modify decision-making when caring for patients with serious neurological conditions.Methods: Patients were prospectively recruited from March 2017 to September 2018 from a tertiary hospital to establish the development cohort for the internal test of the nomogram, while patients recruited from October 2018 to June 2019 from another tertiary hospital prospectively constituted the validation cohort for the external validation of the nomogram. A multivariate logistic regression analysis was performed in the development cohort using a backward stepwise method to determine the best-fit model for the nomogram. The nomogram was subsequently validated in an independent external validation cohort for discrimination and calibration. A decision-curve analysis was also performed to evaluate the net benefit of the insertion decision using the nomogram.Results: A total of 280 patients were enrolled in the development cohort, of whom 42 (15.0%) died, whereas 237 patients were enrolled in the validation cohort, of which 43 (18.1%) died. COP, neurological pathogenesis and Acute Physiology and Chronic Health Evaluation II (APACHE II) score were predictors in the prediction nomogram. The derived cohort demonstrated good discriminative ability, and the area under the receiver operating characteristic curve (AUC) was 0.895 [95% confidence interval (CI), 0.840–0.951], showing good correction ability. The application of this nomogram to the validation cohort also provided good discrimination, with an AUC of 0.934 (95% CI, 0.892–0.976) and good calibration. The decision-curve analysis of this nomogram showed a better net benefit.Conclusions : A prediction nomogram incorporating COP, neurological pathogenesis and APACHE II score could be convenient in predicting mortality for critically ill neurological patients.

Albumin is an interface between blood plasma and cell membrane, and not just a sponge.

ABSTRACTAlbumin is the most abundant protein in blood plasma and acts as a carrier for many circulating molecules. Hypoalbuminaemia, mostly caused by either renal or liver disease or malnutrition, can perturb vascular homeostasis and is involved in the development of multiple diseases. Here we review four functions of albumin and the consequences of hypoalbuminaemia on vascular homeostasis. (i) Albumin is the main determinant of plasma colloid osmotic pressure. Hypoalbuminaemia was therefore thought to be the main mechanism for oedema in nephrotic syndrome (NS), however, experimental studies showed that intrarenal mechanisms rather than hypoalbuminaemia determine formation and, in particular, maintenance of oedema. (ii) Albumin functions as an interface between lysophosphatidylcholine (LPC) and circulating factors (lipoproteins and erythrocytes) and the endothelium. Consequently, hypoalbuminaemia results in higher LPC levels in lipoproteins and erythrocyte membrane, thereby increasing atherosclerotic properties of low-density lipoprotein and blood viscosity, respectively. Furthermore, albumin dose-dependently restores LPC-induced inhibition of vasodilation. (iii) Hypoalbuminaemia impacts on vascular nitric oxide (NO) signalling by directly increasing NO production in endothelial cells, leading to reduced NO sensitivity of vascular smooth muscle cells. (iv) Lastly, albumin binds free fatty acids (FFAs). FFAs can induce vascular smooth muscle cell apoptosis, uncouple endothelial NO synthase and decrease endothelium-dependent vasodilation. Unbound FFAs can increase the formation of reactive oxygen species by mitochondrial uncoupling in multiple cell types and induce hypertriglyceridemia in NS. In conclusion, albumin acts as an interface in the circulation and hypoalbuminaemia impairs multiple aspects of vascular function that may underlie the association of hypoalbuminaemia with adverse outcomes. However, hypoalbuminaemia is not a key to oedema in NS. These insights have therapeutic implications.

Safety and efficacy of cell-free and concentrated ascites reinfusion therapy against cirrhotic ascites in comparison with malignancy-related ascites.

Cell-free and concentrated ascites reinfusion therapy (CART) has been performed against cirrhotic ascites, one of the most common complications seen in patients with decompensated cirrhosis. The aim of this study is to investigate its safety and efficacy, and differences in clinical profiles from CART against malignancy-related ascites with different pathological background. The present investigation involved a sub-analysis of data obtained from a prospective observational study of CART performed at 22 centers. The condition of each procedure, therapeutic options, laboratory data, performance status, dietary intake, and abdominal circumference of participants were analyzed. Clinical parameters were compared between before and after CART, with or without albumin infusion, and also primary diseases including cirrhosis and malignant disease. Between January 2014 and January 2015, a total of 48 and 275 CART procedures were performed in patients with cirrhosis and malignancies. In cirrhotic patients, serum albumin concentration increased significantly in groups both with and without concomitant albumin infusion (P=0.002 and P=0.023), and no significant difference in CART interval was seen between these groups (P=0.393). CART interval was not significantly different between cirrhosis and malignancy groups (P=0.334). Dietary intake significantly improved after CART in both groups (P=0.043 and P<0.001). Adverse events were with no clinical significance as observed in patients with malignancies. Cell-free and concentrated ascites reinfusion therapy was performed safely and effectively in patients with ascites related to decompensated cirrhosis and offers the potential efficacy to maintain plasma colloid osmotic pressure after paracentesis as well as in patients with malignancy.

Expert consensus on the use of human serum albumin in critically ill patients.

Expert consensus on the use of human serum albumin in critically ill patients.

A randomized dose-escalation study on the safety, tolerability, immunogenicity, pharmacokinetics and pharmacodynamics of a novel recombinant human albumin in healthy subjects

ObjectiveRecombinant human albumin (rHA) is an alternative to human serum albumin (HSA) for treating ascites in cirrhosis patients. This study was to evaluate the safety, tolerability, immunogenicity, and pharmacokinetics/pharmacodynamics (PK/PD) of rHA in healthy subjects to guide the design for further clinical trials. MethodsHealthy subjects aged 18–55 years were enrolled in this double-blinded, first-in-human, placebo-controlled single ascending dose (SAD) (1.25, 5, 10, 20, or 30g) and positive-controlled multiple-dose study (3-day treatment of 10g/day for three cycles every three weeks). The safety was assessed by adverse events (AEs). Antibodies (IgE and IgD) and cytokines were analyzed for immunogenicity. Serum albumin levels and changes in plasma colloid osmotic pressure (PCOP) and hematocrit (HCT) were measured for PK/PD analysis. ResultsrHA was well tolerated as all AEs were assessed as mild or moderate. No severe allergy or difference in the incidence of AEs was observed among the different cohorts in the SAD study or in the different cycles in the multiple-dose study. The incidence of AEs was similar for the rHA and HSA cohort. Antibodies or cytokines showed no changes after drug administration. As expected, serum albumin levels and PCOP increases, and HCT ratio decreases were dose-related with significant differences (p < 0.01). No differences were observed between rHA and HSA. ConclusionrHA is safe and well-tolerated in healthy Chinese subjects. rHA and HSA exhibited similar safety, tolerability, and PK/PD profiles. The results support further evaluation of rHA treatment in cirrhotic patients with ascites. The clinical trial registration numbers are CTR20191221 (http://www.chinadrugtrials.org.cn/clinicaltrials.searchlistdetail.dhtml).

Plasma colloid osmotic pressure in preeclampsia. Review of the Mexican literature 1997-2018.

En México, la presión coloidosmótica del plasma ha sido un tema clave del estudio de la mujer embarazada por más de dos décadas. Las investigaciones clínicas han permitido conocer sus valores en población abierta, mujeres con embarazo normal, puerperio fisiológico, preeclampsia severa, síndrome HELLP y eclampsia. También se ha reportado la relación de la presión coloidosmótica del plasma con la presión sanguínea (índice de Briones), síndrome de fuga capilar y la acumulación de líquido en cavidades serosas (derrame pleural, ascitis). Revisamos la base de datos PubMed, The Cochrane Library, OVID, Science Direct, Google Scholar, Artemisa, LILACS e IMBIOMED de 1997 a 2018 con las siguientes palabras clave: albúmina sérica, presión coloidosmótica del plasma, síndrome de fuga capilar, índice de Briones, derrame pleural, ascitis, preeclampsia severa, síndrome HELLP, eclampsia y cuidados críticos en obstetricia. Los criterios de inclusión fueron revisiones sistemáticas, meta-análisis, ensayos clínicos controlados y artículos con metodología de medicina basada en evidencia con recomendaciones sólidas. Incluimos 12 artículos mexicanos. Los objetivos de la presente investigación fueron: revisar la literatura médica de la presión coloidosmótica del plasma en preeclampsia reportada de 1997 a 2018, describir el tratamiento con albúmina humana y las perspectivas de la investigación en los siguientes años.In Mexico, plasma colloid osmotic pressure has been a key issue in the study of pregnant women for more than two decades. Clinical investigations have allowed to know their values in the open population, as well as in women with normal pregnancy, physiological puerperium, severe preeclampsia, HELLP syndrome, and eclampsia. The relationship of plasma colloid osmotic pressure with mean arterial pressure (Briones index), capillary leak syndrome and the accumulation of fluid in serous cavities (pleural effusion, and ascites) have also been reported. We reviewed the database of PubMed, The Cochrane Library, OVID, Science Direct, Google Scholar, Artemisa, LILACS, and IMBIOMED from 1997 to 2018 with the following keywords: serum albumin, plasma colloid osmotic pressure, capillary leak syndrome, Briones index, pleural effusion, ascites, severe preeclampsia, HELLP syndrome, eclampsia, and obstetrics critical care. Inclusion criteria were systematic reviews, meta-analysis, clinical controlled trials, and articles with evidence-based medicine methodology with strong recommendations. We included 12 Mexican articles. The objectives of the present investigation were to review the medical literature on plasma colloid osmotic pressure in preeclampsia reported from 1997 to 2018, describe the treatment with human albumin and the perspectives of the research in the following years.

Atrial natriuretic peptide does not degrade the endothelial glycocalyx: A secondary analysis of a randomized porcine model.

The atrial natriuretic peptide (ANP) released from the heart regulates intravascular volume and is suspected to increase capillary permeability. Contradictory results regarding ANP and glycocalyx degradation have been reported. The aim of this study was to investigate if an infusion of ANP causes degradation of the endothelial glycocalyx. Twenty pigs, pretreated with 250mg methylprednisolone, were randomized to receive an infusion of either ANP (50ng/kg/min) (n=10) or 0.9% NaCl (n=10) during 60min. Endothelial glycocalyx components (heparan sulphate proteoglycan and hyaluronic acid), Hct, calculated plasma volume and colloid osmotic pressure were measured from baseline to 60min. There was no difference between the control and intervention groups for heparan sulphate proteoglycan and hyaluronic acid corrected for the change in plasma volume (P=.333 and 0.197). Hct increased with 1.8±2.2% in the intervention group (P=.029) with no change -0.5±2.3% in the control group (P=.504). The plasma volume decreased in the intervention group with -8.4±10% (P=.034) with no change in the control group 3.1±12% (P=.427). Median changes in colloid osmotic pressures in the control and intervention group were -0.39 [95% CI, -1.88-0.13] and 0.9 [95% CI, 0.00-1.58], respectively (P=.012). In this randomized porcine study, an ANP infusion did not cause endothelial glycocalyx degradation but decreased the plasma volume most probably due to precapillary vasodilation and increased filtration.

The Effect of Hemodialysis on Axial Length, Ocular Surface, and Intraocular Pressure in Patients with End-Stage Renal Failure.

PurposeTo evaluate the changes in intraocular pressure (IOP), central corneal thickness (CCT), axial length, and ocular surface in patients with end-stage renal failure after single-session hemodialysis treatment and to examine the correlation of these findings with systemic hemodynamic parameters.Patients and MethodsA total of 112 eyes of 112 patients enrolled in a hemodialysis treatment program for three times a week (approximately four hours per session) for at least three months in our hospital between December 2019 and March 2020 were included in the study. Approximately 30 minutes before and after hemodialysis, the best-corrected visual acuity measurement, slit-lamp examination, IOP measurement, and dilated fundus examination with the Goldmann applanation tonometer were performed in all patients. The axial length measurement was undertaken by ultrasonic biometry, and the CCT measurement by ultrasonic pachymetry. The ocular surface evaluation was performed based on the tear breakup time (BUT), basal secretion time (BST) and keratoepitheliopathy score. Blood pressure, serum osmolarity, and body weight were measured before and after hemodialysis.ResultsThe mean IOP decreased from 12.2 ± 3.5 to 10.8 ± 2.2 mmHg, and the mean decrease was 1.4 ± 2 mmHg, indicating statistical significance (p<0.001). The mean CCT dropped from 502 ± 41.2 to 494.1 ± 35.4 μm, and the mean decrease was 8.1 ± 7.7 μm, which also indicated a statistically significant change (p<0.001). The mean axial length was reduced from 23.1 ± 0.8 to 22.9 ± 0.8 mm. The reduction in the axial length was significant with an average value of 0.26 ± 0.15 mm (p<0.001). When the ocular surface changes were examined, BUT decreased from 7.4 ± 3.1 to 6.3 ± 2.5 s, BST from 8.6 ± 1.7 to 6.6 ± 1.3 mm, and the keratoepitheliopathy score increased from 0.36 ± 0.61 to 1.59 ± 0.93, and all these changes were statistically significant (p<0.001). There was a significant correlation between the axial length change and the IOP change (r=0.202, p=0.03). A significant correlation was also observed between BST and plasma colloid osmotic pressure (r=−0.268, p=0.004). In addition, there was a strong correlation between serum osmolarity and the keratoepitheliopathy score (r=−0.437, p<0.001).ConclusionHemodialysis causes significant changes in IOP, CCT, axial length, and ocular surface. These changes should be considered in the ophthalmological examination of patients after the hemodialysis session.

Evaluation of the effects of hydroxyethyl starch (130/0.4) administration as a constant rate infusion on plasma colloid osmotic pressure in hypoabluminemic dogs.

To evaluate the effects of 2 constant rate infusions of hydroxyethyl starch (HES) 130/0.4 on plasma colloid osmotic pressure (COP) in hypoalbuminemic dogs. Prospective, randomized clinical trial. A total of 24 client-owned dogs. Hypoalbuminemic euvolemic dogs (albumin<20g/L[<2g/dL]) with normal perfusion parameters requiring IV fluid therapy were enrolled. In addition to crystalloid, HES 130/0.4 was administered as a constant rate infusion over 24hours at 1mL/kg/h (group 1, n=15) or at 2mL/kg/h (group 2, n=9), in order to support plasma COP. Before infusion, a blood sample was collected to perform CBC, serum electrophoresis, and serologic tests for some infective diseases. Plasma COP, albumin concentration, PCV, and total plasma protein concentration were evaluated serially at baseline (T0) and then at 6, 12, and 24hours after the start of infusion, and a multilevel model was performed for these parameters to detect statistically significant differences between the 2 groups. Twenty-four dogs were included. No statistically significant differences in COP werefound between the 2 groups; however, a high level of variability has been identified within the single individual. Among the other laboratory analyses, PCV was significantly decreased in group 1 at T12 and T24 compared with T0 (P<0.001) and total plasma protein concentration was significantly increased in group 2 at T12 and T24 compared with T0 (P<0.008). No significant effect on plasma COP was found following infusion with HES 130/0.4 at doses of 1mL/kg/h and 2mL/kg/h for 24hours to hypoalbuminemic dogs. The administered concomitant dose of crystalloids, underlying disease, and small sample size were all potential confounding factors.

L’hypo-albuminémie contribue-t-elle à l’aggravation de l’insuffisance cardiaque ?

BackgroundHypoalbuminemia has now emerged as a powerful prognosticator in heart failure regardless of age, clinical presentation, left ventricular ejection fraction and usual prognostic markers. Growing evidence is that this prognostic value persists after adjusting for causative factors for hypoalbuminemia such as malnutrition, inflammation and liver dysfunction. ObjectiveTo address the prognostic relevance of hypoalbuminemia in frail elderly patients with well-characterized cardiogenic pulmonary edema at high risk for adverse outcome, beyond causative factors for low serum albumin levels. Serum albumin was measured after clinical stabilization to avoid hypervolemia. ResultsIn all, 67 patients with a mean age of 86 years were included. Hospital mortality was 30%. Patients who died and who survived were similar in age, ejection fraction, BNP concentration, serum creatinine, serum hemoglobin, total bilirubin and prealbumin. Patients who died had lower serum albumin levels (P<0.001), higher blood urea nitrogen (P=0.03) and higher C-reactive protein (P=0.02). In multivariate analysis, serum albumin was the sole independent predictor of hospital death (P<0.01), after adjusting for malnutrition (prealbumin P=ns), inflammation (C-reactive protein P=ns) and liver dysfunction (total bilirubin P=ns). ConclusionSerum albumin is a powerful prognosticator in frail elderly patients with acute cardiogenic pulmonary edema even after adjusting for main causative factors. These results suggest that hypoalbuminemia may contribute to the worsening of heart failure given the physiological properties of serum albumin that includes antioxidant activity and plasma colloid osmotic pressure action. Further studies are critically needed to address the relevance of prevention and correction of hypoalbuminemia in heart failure.

P1090DETERMINATION OF ABSOLUTE BLOOD VOLUME USING ONLINE DIALYSATE DILUTION: WHEN SHOULD BE MEASURED?

Abstract Background and Aims Current on-line haemodiafiltration (HDF) machines equipped with a blood volume monitor (BVM) and an on-line bolus function have the potential for measuring absolute blood volume (aBV). Recently, we developed a simple method to determine absolute BV in everyday dialysis sessions. The aim of the present study was to evaluate the reproducibility of measurements. Method Intra-individual reproducibility was studied in 10 patients during a single dialysis session by 4 measurements of absolute BV: immediately after beginning before ultrafiltration (UF) was started, and after one, two and three hours. ABV was determined by indicator dilution. A defined volume bolus of 240 mL dialysate was infused into the venous blood line by pressing the emergency button of the HDF machine 5008 (FMC). For this reason, total UF volume was increased by 1L. UF was automatically stopped during and after the infusion. The resulting increase in relative blood volume (RBVpost-RBVpre) was measured by the ultrasonic relative BVM incorporated in the dialysis machine. ABV was measured in hourly intervals and for assessment of reproducibility the volume at treatment start (t=0) where RBV is 100% was calculated for all measurements as: aBV in mL = bolus volume 240 mL x 100% / increase RBV in % ABV data were normalized for body mass at dry weight (in mL/kg). Additionally, in 5 patients the RBV graph was monitored immediately at the beginning of dialysis without UF in a separate dialysis session. Results ABV at t=0 were consistently larger when calculated from measurements done immediately after the beginning compared to measurements obtained after 1 h (6.52 ± 1.40 L or 80.6 ± 14.5 mL/kg vs. 5.16 ± 1.40 L or 63.9 ± 14.3 mL/kg). Specific BV derived from 2 and 3 h measurements did not significantly differ from the measured volumes after 1 hour (61.4 ± 13.8 mL/kg, and 60.9 ± 13.9 mL/kg). The standard deviations of the 3 examinations in the same study patient during a further course of dialysis were between 0.6 and 5.3 ml/kg (ø 2.6 ml/kg). In a separate session, RBV decreases without UF at the beginning of dialysis in the first 3 minutes by 0.5 % and in 5 minutes by 0.6 %. Conclusion If BV is diluted by additional priming volume and bolus volume, a part of this volume will leave the circulation. This represented the time frame where the bolus was initially infused and the measurements were carried out. This loss is caused by the reduction in plasma colloid osmotic pressure induced by the dilution thereby changing the microvascular filtration equilibrium. The increase in RBV display is not solely caused by the bolus volume in this time and, and therefore, calculated BV would be overestimated by about 17 mL/kg. If measurement is performed at a later time, UF will take place and, consequently, refilling. This inward drive matches the outward bolus escape as a counterforce. BV measurement during a further course of dialysis is well reproducible with a deviation of only ± 2.6 ml/kg. The method would therefore be sufficiently precise in clinical practice. Therefore, we propose the determination of aBV only after 1 hour dialysis when a sufficient refilling takes place. With a software modification, the BV measurement could be routinely automated during each dialysis treatment. Manufacturers are asked to implement this technology in their devices.