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

BACKGROUND: As 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. METHODS: In 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. RESULTS: The 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). CONCLUSION: The 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 REGISTRATION: Chinese Clinical Trial. no. ChiCTR2100045671. Registry at www.chictr.org.cn on April 20, 2021.

Moderator Effect of Hypoalbuminemia in Volume Resuscitation and Plasma Expansion with Intravenous Albumin Solution.

Intravenous administration of crystalloid or colloid solutions is the most common intervention for correcting hypovolemia in intensive care unit patients. In critical illness, especially sepsis and severe trauma, vascular wall permeability increases, and trans-endothelial escape of serum albumin, the major oncotic plasma constituent, contributes to the development of hypoalbuminemia and edema formation. The volume effects of intravenous human albumin solution exceed those of crystalloid solutions. If hypoalbuminemia is an effect moderator, the crystalloid-to-albumin ratio of fluid resuscitation volumes is not well characterized. Randomized controlled trials have confirmed that intravenous administration of human albumin solutions for volume resuscitation results in a lower net fluid balance compared with crystalloids, and smaller infusion volumes may be sufficient for hemodynamic stabilization when human albumin solutions are used. This narrative review summarizes the current evidence and conclusions drawn regarding the role of hypoalbuminemia in volume resuscitation. In the 'Saline versus Albumin Fluid Evaluation' study using 4% human albumin solution or saline, the saline-to-albumin ratio of study fluids was significantly higher in patients with baseline serum albumin concentrations of 25 g/L or less as compared to patients with baseline serum albumin concentrations of more than 25 g/L. In patients receiving renal replacement therapy, intravenous administration of 20-25% human albumin solution reduces intradialytic hypotension and improves fluid removal better than saline if serum albumin levels are similarly reduced. These data suggest that hypoalbuminemia acts as an effect moderator in volume resuscitation and plasma expansion with albumin solution. The volume effectiveness of intravenous human albumin solution in resuscitation appears to be greater when the serum albumin levels are low. In clinical situations, serum albumin concentrations per se may inform when and how to include intravenous albumin in fluid resuscitation if large amounts of crystalloids are needed, which requires further studies.

Hemoglobin-albumin clusters as an artificial O2 carrier: Physicochemical properties and resuscitation from hemorrhagic shock in rats.

A bovine hemoglobin (HbBv) or human adult hemoglobin (HbA) wrapped covalently by human serum albumins (HSAs), hemoglobin-albumin clusters (HbBv-HSA3 and HbA-HSA3 ), are artificial O2 carriers used as a red blood cell substitute. This article describes the physicochemical properties of the HbBv-HSA3 and HbA-HSA3 solutions, and their abilities to restore the systemic condition after resuscitation from hemorrhagic shock in anesthetized rats. The HbBv-HSA3 and HbA-HSA3 , which have high colloid osmotic activity, showed equivalent solution characteristics and O2 binding parameters. Shock was induced by 50% blood withdrawal. Rats exhibited hypotension and significant metabolic acidosis. After 15 min, the rats were administered shed autologous blood (SAB), HbBv-HSA3 , HbA-HSA3 , or Ringer's lactate (RL) solution. Survival rates, circulation parameters, hematological parameters, and blood gas parameters were monitored during the hemorrhagic shock and for 6 h after administration. All rats in the SAB, HbBv-HSA3 , and HbA-HSA3 groups survived for 6 h. The HbBv-HSA3 and HbA-HSA3 groups restored mean arterial pressure after the resuscitation. No remarkable difference was observed in the time courses of blood gas parameters in any resuscitated group except for the RL group. Serum biochemical tests showed increases in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HbBv-HSA3 and HbA-HSA3 groups compared to the SAB group. Therefore, we observed other rats awakened after resuscitation with HbA-HSA3 for 7 days. The blood cell count, AST, and ALT recovered to the baseline values by 7 days. All the results implied that HbBv-HSA3 and HbA-HSA3 clusters provide restoration from hemorrhagic shock as an alternative material for SAB transfusion.

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.

The Colloid Osmotic Pressure Across the Glycocalyx: Role of Interstitial Fluid Sub-Compartments in Trans-Vascular Fluid Exchange in Skeletal Muscle.

The primary purpose of these investigations is to integrate our growing knowledge about the endothelial glycocalyx as a permeability and osmotic barrier into models of trans-vascular fluid exchange in whole organs. We describe changes in the colloid osmotic pressure (COP) difference for plasma proteins across the glycocalyx after an increase or decrease in capillary pressure. The composition of the fluid under the glycocalyx changes in step with capillary pressure whereas the composition of the interstitial fluid takes many hours to adjust to a change in vascular pressure. We use models where the fluid under the glycocalyx mixes with sub-compartments of the interstitial fluid (ISF) whose volumes are defined from the ultrastructure of the inter-endothelial cleft and the histology of the tissue surrounding the capillaries. The initial protein composition in the sub-compartments is that during steady state filtration in the presence of a large pore pathway in parallel with the "small pore" glycocalyx pathway. Changes in the composition depend on the volume of the sub-compartment and the balance of convective and diffusive transport into and out of each sub-compartment. In skeletal muscle the simplest model assumes that the fluid under the glycocalyx mixes directly with a tissue sub-compartment with a volume less than 20% of the total skeletal muscle interstitial fluid volume. The model places limits on trans-vascular flows during transient filtration and reabsorption over periods of 30-60 min. The key assumption in this model is compromised when the resistance to diffusion between the base of the glycocalyx and the tissue sub-compartment accounts for more than 1% of the total resistance to diffusion across the endothelial barrier. It is well established that, in the steady state, there can be no reabsorption in tissue such as skeletal muscle. Our approach extends this idea to demonstrate that transient changes in vascular pressure favoring initial reabsorption from the interstitial fluid of skeletal muscle result in much less fluid exchange than is commonly assumed. Our approach should enable critical evaluations of the empirical models of trans-vascular fluid exchange being used in the clinic that do not account for the hydrostatic and COPs across the glycocalyx.

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.

Update on Albumin Therapy in Critical Illness.

Albumin is among the most important proteins and plays a significant role in maintenance of colloid osmotic pressure, wound healing, decreasing oxidative damage, carrying drugs and endogenous substances, and coagulation. Hypoalbuminemia is common in acute and chronic illnesses. Replenishment of albumin can be in the form of fresh frozen, frozen or cryopoor plasma, or in the form of human or canine albumin concentrates. Infusion of human albumin concentrate to healthy and critically ill dogs can induce acute and delayed hypersensitivity reactions. Death has been reported. Therefore, allogenic transfusion in the form of plasma products or canine albumin concentrate is recommended.

Effect of two different colloid priming strategies in infants weighing less than 5 kg undergoing on-pump cardiac surgeries.

Our aim was to explore the effect of two different priming strategies (artificial colloid only vs. artificial colloid combined with human serum albumin) on the prognosis of children weighing less than 5 kg undergoing on-pump congenital heart disease (CHD) surgery. A total of 65 children weighing less than 5 kg who underwent on-pump CHD surgery in our hospital from September 2016 to December 2017 were enrolled in this study. The children were randomly divided into two groups: artificial colloid priming group (AC group, n = 33) and artificial colloid combined albumin priming group (ACA group, n = 32). The primary clinical endpoint was the peri-CPB colloid osmotic pressure (COP). Secondary clinical endpoints included perioperative blood product and hemostatic drug consumption, postoperative renal function, coagulation function, postoperative renal function, and postoperative recovery parameters. COP values were not significant in the priming system as well as peri-CPB time points between the two groups (P > .05). Platelet consumption in the AC group was significantly lower than that in the ACA group (P < .05). There were no significant differences in the use of other blood products and hemostatic drugs as well as perioperative coagulation parameters between the two groups (P > .05). Postoperative length of stay in the AC group was significantly lower than that in the ACA group (P < .05). There were no significant differences in mortality, postoperative mechanical ventilation time, ICU time, and perioperative adverse events (including postoperative AKI) occurrences between the two groups (P > .05). In the on-pump cardiac surgeries of patients weighing less than 5 kg, total colloidal priming would not affect peri-CPB COP values, postoperative coagulation function, and blood products consumption. Total artificial colloidal priming strategy is feasible in low-weight patients.

Hydroxyethyl starch 130/0.4 (6%) and succinylated gelatine (4%) interfere with refractometry in dogs with haemorrhagic shock.

OBJECTIVE: To determine if low molecular weight synthetic colloid fluids administered to dogs interfere with refractometric estimates of total plasma protein (TPPr) and urine osmolality (UOsm). STUDY DESIGN: Experimental study. ANIMALS: Eighteen healthy Greyhound dogs. METHODS: Anaesthetized Greyhounds subjected to haemorrhage for 60 minutes were given 80 mL kg-1 of Plasma-Lyte 148 (CRYST), or 20 mL kg-1 of hydroxyethyl starch 130/0.4 (HES) or succinylated gelatine (GELO) (n = 6 per group) intravenously over 20 minutes. Refractometric (TPPr) and biuret total plasma protein (TPPb) were measured before haemorrhage (Baseline), at end of shock (Shock), immediately (T20), then 40 minutes (T60), 100 minutes (T120) and 160 minutes (T180) after fluid administration. Urine specific gravity (USG) and UOsm were measured at all time points except T20. Estimated UOsm (eUOsm) was calculated from USG. Bias and limits of agreement (LOA) for TPPr versus TPPb, and eUOsm versus UOsm were calculated at each time point. RESULTS: For dogs given CRYST and GELO, median TPPr and TPPb decreased in parallel, with a small consistent TPP bias (CRYST range of bias, 0.38-0.67 g dL-1; GELO range of bias, 0.42-0.58 g dL-1). Dogs given HES showed divergence between median TPPr and TPPb after T20, with a peak bias at T20 of 1.62 g dL-1 (LOA 1.29-1.95). Dogs given HES and GELO had markedly increased USG [HES peak median USG at T180 of 1.119 (Q1-Q3 1.103-1.122); GELO peak median USG at T120 of 1.114 (Q1-Q3 1.082-1.119)], with large increases in bias between eUOsm and UOsm [HES peak bias at T60 of 2995 mOsm kg-1 (LOA 2032-3958 mOsm kg-1); GELO peak bias at T120 of 2465 mOsm kg-1 (LOA 940-3990 mOsm kg-1)]. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of HES and GELO to dogs with haemorrhagic shock interferes with refractometric measurements for at least 3 hours after administration.

PLASMA COLLOID OSMOTIC PRESSURE IN CHRONICALLY DEBILITATED LOGGERHEAD SEA TURTLES (CARETTA CARETTA).

Colloid osmotic pressure (COP) is an important component of the forces that manage capillary filtration and is determined by circulating plasma proteins. Patients affected by conditions resulting in hypoproteinemia often suffer severe hemodynamic derangements, including decreased COP. Because chronically debilitated sea turtles (CDT) present with severe hypoproteinemia, the objectives of this study were to 1) determine differences in plasma COP and blood analyte data (packed cell volume [PCV], sodium, chloride, plasma protein fractions) in CDT at admission compared with data from apparently healthy rehabilitated turtles at time of release (HRT) admitted from various stranding causes, and 2) to investigate correlations of COP with these selected blood analytes. COP, PCV, and most plasma protein fractions (excluding pre-albumin and γ-globulins) were significantly lower in CDT upon admission as compared with HRT. Sodium and chloride did not significantly differ between CDT and HRT. A significant increase was observed with PCV and all plasma protein fractions as COP increased. Of all protein fractions tested, albumin contributed the most toward COP (r2 = 0.88, P < 0.001). The results of this study suggest that COP is significantly lower in CDT as compared with HRT, providing insight into the complexity of this critical clinical condition and a small step in advancing the understanding of associated hemodynamic imbalances. Although COP analysis is not readily available as a diagnostic test, this preliminary baseline data suggests that additional research studies are warranted, given the potential for optimization of fluid therapy during rehabilitation of CDT.

Serum biochemical determinants of peripheral congestion assessed by bioimpedance vector analysis in acute heart failure.

BACKGROUND: The pathophysiology of peripheral congestion is poorly investigated in patients with acute heart failure (AHF). OBJECTIVES: to evaluate the relative contribution of serum colloid osmotic pressure (COP), relative plasma volume status (PVS), biomarkers of renal function, electrolytes, haemoglobin, and brain natriuretic peptide (BNP) in peripheral fluid overload using bioimpedance vector analysis (BIVA). METHODS: We retrospectively analysed data from 485 patients with AHF. Hydration status was evaluated by semiquantitative and quantitative approach using BIVA (R/Xc graph) and Hydration Index (HI), respectively. COP was calculated from albumin and total protein concentration, while relative PVS was calculated from validated equations. RESULTS: Congestion assessed by BIVA was observed in 304 (63%) patients and classified as mild (30%), moderate (42%), and severe (28%). On univariate analysis, HI was inversely correlated with COP (P < 0.01), glomerular filtration rate (P < 0.01), and haemoglobin (P < 0.01), while positive correlations were found for relative PVS (P < 0.05), BNP (P < 0.01), and blood urea nitrogen (BUN; P < 0.01). On stepwise multivariate analysis, COP explained 12% of the total variability, while BUN, PVS, haemoglobin, and BNP added a further 6%, 4%, 2%, and 1%, respectively, to the final explanatory model. CONCLUSIONS: COP was the major determinant of the presence and entity of peripheral congestion assessed by BIVA. BUN, PVS, haemoglobin, and BNP revealed reduced influence on congestion as compared with COP. Routine laboratory testing could be useful in peripheral fluid accumulation. Future studies should evaluate the relationship between COP and pharmacological target therapies for the fluid management of AHF patients.

Clinical use of cryopoor plasma continuous rate infusion in critically ill, hypoalbuminemic dogs.

OBJECTIVE: To investigate the impact of cryopoor plasma (CPP) continuous rate infusion (CRI) on albumin concentration and colloid osmotic pressure (COP) in critically ill dogs with hypoalbuminemia. DESIGN: Retrospective study between 2013 and 2015 with a 90-day follow-up on survivors. SETTING: University teaching hospital. ANIMALS: Ten hypoalbuminemic dogs receiving a CPP CRI for albumin replacement or oncotic support. All patients with documented hypoalbuminemia or low COP receiving CPP administration for albumin or oncotic support during the study period were included. INTERVENTIONS: CRI of CPP. MEASUREMENTS AND MAIN RESULTS: Mean age was 7.4 ± 4.5 years. Mean survival prediction index score was 0.66 ± 0.13. Seven dogs were septic, with 2 of 7 in septic shock and 5 of 7 having septic peritonitis. The mean pre- and postinfusion albumin was 15 ± 4 g/L and 21 ± 2 g/L, respectively. The median pre- and postinfusion COP was 8.6 mm Hg (4.9-9.7 mm Hg) and 10.2 mm Hg (8.1-13.3 mm Hg), respectively. The median duration of CRI was 16 hours (11-121 h). The mean CPP rate was 1.8 ± 0.6 mL/kg/h, the mean crystalloid rate administered concurrently was 0.8 ± 0.9 mL/kg/h, and the mean hydroxyethyl starch rate administered concurrently was 1.2 ± 0.9 mL/kg/h. The difference in pre- and postinfusion albumin was significantly correlated with CPP rate (P = 0.0004), whereas the difference in pre- and postinfusion COP was correlated with hydroxyethyl starch rate (P = 0.0128). Mean duration of hospitalization was 8.6 ± 3.9 days. Mann-Whitney U and Fisher's exact tests were used to compare survivors and nonsurvivors. Survivors were significantly younger than nonsurvivors (3.5 vs 11.5 y, P = 0.033). No side effects were reported. Survival to discharge was 40% with identical 90-day survival. Of the nonsurvivors, 50% died naturally. CONCLUSIONS: There was an association between the rate of CPP and the change in albumin after CPP CRI in critically ill dogs, suggesting that CPP may be a viable option for treatment of hypoalbuminemia.

Using Dramatization to Teach Starling Forces in the Microcirculation to First-Year Medical Students.

Introduction: The clinical importance, prevalence, and multiple etiologies of tissue edema make it a critical part of medical education. Given the multiple physiological parameters that must be simultaneously considered to determine fluid movement, it is important that a deeper understanding of the microcirculation and fluid shifts is achieved in preclinical education. Methods: We describe an innovative teaching methodology using dramatization to interactively teach Starling forces to first-year medical students. Prior to the dramatization, students were given an introduction to Starling forces. They also completed a brief knowledge quiz on the topic before and after the activity. The classroom walls were marked with signs representing the intravascular space, extravascular or interstitium, and lymphatics compartments. Students were invited to act out or mimic the fluid shifts within capillaries as the values for hydrostatic and colloid osmotic pressures for the intravascular and interstitial spaces were presented. The goal was for each student to decide which compartment he/she would move to as fluid according to Starling force values and/or clinical scenarios. Results: A significant improvement between pre- and postactivity quiz performance (45.4% ± 25.1% and 77.5% ± 14.1%, respectively) was observed (n = 26, p < .001, t test). In a postactivity survey, 85% of students reported the activity to be an effective way of learning. Discussion: Our data indicate that this dramatization approach is effective in complementing passive learning in traditional lectures. Furthermore, this type of dynamic activity brings joy to the classroom and breaks the monotony of lecturing.

The Influence of Colloid Osmotic Pressure on Hydrostatic Pressures in High- and Low-Flux Hemodialyzers.

The aim of this study was to examine the relationship between hydrostatic trans-membrane pressure (TMPh ) and colloid osmotic pressure (COP) in low-flux (LF) and high-flux (HF) dialyzers. Hydrostatic pressures were measured in dialyzers distinguished by their ultrafiltration coefficient Kuf (16 and 85 mL/h/mm Hg) under constant dialysate flow and variable blood flow (Qb ) ranging from 0 to 400 mL/min using (i) alginate (70 kDa) dissolved in dialysate, (ii) diluted, undiluted, and concentrated plasma, or (iii) whole blood at different hematocrit, all in absence of ultrafiltration (UF). For a given fluid, TMPh linearly increased with increasing Qb . The intercept of the linear TMPh to Qb relationship correlated with measured COP with an average bias of 1.00 ± 2.26 mm Hg and a concordance correlation coefficient of 0.98. The slope of the linear TMPh to Qb relationship increased with increasing sample viscosity and was much larger in HF dialyzers under otherwise identical operating conditions, most likely because of increased internal filtration. The TMPh to Qb relationship measured in dialyzers in absence of UF can be described by the intercept related to measured COP and the slope related to internal filtration. This relationship could be of interest to estimate internal filtration and COP under in vivo conditions.

Colloid osmotic pressure during and after surgical interventions in adult and geriatric dogs / Pressão coloidosmótica durante e depois de intervenção cirúrgica em cães adultos e geriátricos

The objective this study is to evaluate colloid osmotic pressure (COP) fluctuations in adult and senile dogs during surgical interventions. Thirty-six healthy dogs to surgical interventions, distributed in two groups, A and B, according to their age, and were all subjected to the same anesthetic protocol. Values of albumin, total plasmatic protein and COP were evaluated from samples collected before pre-anesthetic medication, fifteen minutes after pre-anesthetic medication, and shortly after the end of the intervention. Results were tested using t-test to compare among groups and ANOVA for repeated measures followed by Tukey's test to compare different moments within the same group. Statistical significance was set at p<0.05. In both groups, significant decreases were observed in colloid osmotic pressure, as well as albumin and total proteins (p<0.001). Despite slightly lower COP values for the group of adult animals, this difference was not significant as there was a high individual variation within groups. The results therefore indicate no difference in colloid osmotic pressure values or fluctuation patterns among adult and senile dogs (p=0.124). The observed results indicate that colloid osmotic pressure decreases significantly during surgical procedures, due to hypotension caused by the anesthetic drugs and to hemodilution caused by the fluid administration but there is no difference between groups. However, in both adult and senile dogs, these variables recover gradually after the animals awaken, through increased urine production and recovery of vascular tonus, indicating the successful reestablishment of homeostasis.(AU)

O objetivo deste estudo é avaliar as flutuações da pressão coloidosmótica (PCO) em cães adultos e idosos durante a intervenção cirúrgica. Foram utilizados 36 cães hígidos submetidos à intervenção cirúrgica, distribuídos em dois grupos de acordo com a idade e submetidos ao mesmo protocolo anestésico. Os valores de albumina, proteína plasmática total e PCO foram avaliados de amostras coletadas antes da medicação pré-anestésica, 15 minutos após e ao final do procedimento cirúrgico. Os dados obtidos foram analisados através do teste-t para comparação entre os grupos e ANOVA para medidas repetidas seguido do teste de Tukey para comparar diferentes momentos dentro do mesmo grupo. Foram considerados estastisticamente diferentes com p<0.05. Em ambos os grupos foram observados decréscimo dos valores da pressão coloidosmótica, como os valores de albumina e proteína total (p<0.001). Apesar de ligeiramente inferior, os valores de PCO para o grupo adulto não apresentaram diferença significativa. Os resultados indicam que não houve diferença nos valores da pressão oncótica ou padrão de flutuação entre adultos e idosos (p=0,124). Os resultados observados indicam significativo decréscimo da pressão coloidosmótica durante os procedimentos cirúrgicos devido à hipotensão causada pelos fármacos anestésicos e pela hemodiluição causada pela administração de fluídos, mas não houve diferença entre os grupos. Entretanto, tanto em cães adultos como idosos, essas variações retornaram gradualmente após a recuperação dos animals, através do aumento da produção de urina e da recuperação do tônus vascular, indicando restabelecimento da homeostase.(AU)

Fluid accumulation after closure of atrial septal defects: the role of colloid osmotic pressure.

OBJECTIVES: Following paediatric cardiac surgery with cardiopulmonary bypass (CPB), there is a tendency for fluid accumulation. The colloid osmotic pressure of plasma (COPp) and interstitial fluid (COPi) are determinants of transcapillary fluid exchange but only COPp has been measured in sick children. The aim of this study was to assess the net colloid osmotic pressure gradient in children undergoing atrial septal defect closure. METHODS: Twenty-three patients had interventional and 18 had surgical atrial septal defect closures. Interstitial fluid was harvested using a wick method before and after surgery with CPB with concomitant blood samples. COP was measured using a colloid osmometer for small fluid samples. Baseline COP was compared with data from healthy children. RESULTS: COPp at baseline was 21.9 ± 2.8 and 21.4 ± 2.2 mmHg in the interventional and surgical groups, respectively, and was significantly lower than in healthy children (25.5 ± 3.1 mmHg) (P < 0.001). In the surgical group, the use of CPB significantly reduced COPp to 16.9 ± 2.9 mmHg (P < 0.001) and the colloid osmotic gradient [ΔCOP (COPp - COPi)] to 2.9 ± 3.8 mmHg (P < 0.001) compared with interventional procedure. One hour after the procedure, COPi was 15.6 ± 3.8 mmHg and 9.9 ± 2.1 mmHg (P < 0.001) and the ΔCOP was 5.4 ± 3.0 mmHg and 9.1 ± 3.1 mmHg (P < 0.003) in the interventional and surgical groups, respectively. CONCLUSIONS: Baseline COPp and COPi were lower in atrial septal defect patients compared with healthy children. The significantly lower COP gradient during CPB may explain the tendency for more fluid accumulation with pericardial effusion in the surgical group. The increased COP gradient after CPB may represent an oedema-preventive mechanism.

Treating Hypoalbuminemia.

Hypoalbuminemia is common and associated with a variety of disease processes, including those leading to systemic inflammatory response syndrome, gastrointestinal disorders, hepatic disorders, and glomerular diseases. Some animals develop clinical signs directly caused by low serum albumin concentration. There is strong evidence that hypoalbuminemia is associated with worse outcomes; however, evidence justifying albumin supplementation is lacking. Severe adverse events are frequently reported with administration of human serum albumin and there is little evidence of benefit from other products. Most patients will not require administration of albumin-containing products. Clinicians should consider early enteral nutritional supplementation in critically ill patients.

Local fluid transfer regulation in heart extracellular matrix.

The interstitial myocardial matrix is a complex and dynamic structure that adapts to local fluctuations in pressure and actively contributes to the heart's fluid exchange and hydration. However, classical physiologic models tend to treat it as a passive conduit for water and solute, perhaps because local interstitial regulatory mechanisms are not easily accessible to experiment in vivo. Here, we examined the interstitial contribution to the fluid-driving pressure ex vivo. Interstitial hydration potentials were determined from influx/efflux rates measured in explants from healthy and ischemia-reperfusion-injured pigs during colloid osmotic pressure titrations. Adaptive responses were further explored by isolating myocardial fibroblasts and measuring their contractile responses to water activity changes in vitro. Results show hydration potentials between 5 and 60 mmHg in healthy myocardia and shifts in excess of 200 mmHg in edematous myocardia after ischemia-reperfusion injury. Further, rates of fluid transfer were temperature-dependent, and in collagen gel contraction assays, myocardial fibroblasts tended to preserve the micro-environment's hydration volume by slowing fluid efflux rates at pressures above 40 mmHg. Our studies quantify components of the fluid-driving forces in the heart interstitium that the classical Starling's equation does not explicitly consider. Measured hydration potentials in healthy myocardia and shifts with edema are larger than predicted from the known values of hydrostatic and colloid osmotic interstitial fluid pressures. Together with fibroblast responses in vitro, they are consistent with regulatory mechanisms that add local biological controls to classic fluid-balance models.

Perioperative trends in plasma colloid osmotic pressure in horses undergoing surgery.

OBJECTIVE: To compare perioperative trends in plasma colloid osmotic pressure (COP) between horses undergoing orthopedic and colic surgery. DESIGN: Prospective clinical study September 2009-January 2011. SETTING: Veterinary university teaching hospital. ANIMALS: Thirty-three healthy, client-owned horses presenting for orthopedic surgery (non-GI) and 85 client-owned horses presenting for emergency exploratory celiotomy (GI, gastrointestinal). INTERVENTIONS: None. MEASUREMENTS: Data relating to the horse's parameters on presentation, surgical lesion, post-operative management and survival were extracted from computerized clinical records. Heparinized blood samples were taken on presentation (PreOp, pre-operative), on recovery from anesthesia (T0), at 12 (T12) and 24 (T24) hours post recovery. COP was measured within 4 hours of collection. RESULTS: There was no significant difference in PreOp or T0 COP between groups. Both groups had a significant decrease in COP during anesthesia. When compared to their respective pre-operative values, horses in the non-GI group had significantly increased COP at T12, whereas those in the GI group had significantly reduced COP. This trend was continued at T24. Horses in the GI group placed on intravenous crystalloid isotonic fluids post-operatively had a significantly lower COP at T12 and T24. Horses in the GI group that did not survive had significantly lower post-operative COP values at T24. CONCLUSIONS: Horses undergoing exploratory celiotomy had significantly lower COP post-operatively than those horses undergoing orthopedic surgery. This difference was more marked in those horses receiving isotonic crystalloid intravenous fluid therapy post-operatively and in those that did not survive to discharge. In the non-GI group an increase in COP post-operatively was common.

Effects of 10% hydroxyethyl starch (HES 200/0.5) solution in intraoperative fluid therapy management of horses undergoing elective surgical procedures.

The aim of the present study was to investigate the effect of pentastarch on colloid osmotic pressure (COP) and cardiopulmonary function during and up to 24 h after anaesthesia in horses. Twenty-five systemically healthy horses were anaesthetised using isoflurane-medetomidine balanced anaesthesia. Twelve were assigned to treatment with hydroxyethyl starch (HES) (H group) and 13 to no HES (NH group). In the H group, 6 mL/kg of pentastarch 10% HES (200/0.5) was infused over 1 h starting 30 min after induction of anaesthesia. Horses of the NH group received an equal amount of lactated Ringer's solution (LRS). COP and blood biochemical, cardiopulmonary and anaesthesia-related variables were measured at different time points before and after treatment. Pentastarch was effective in correcting the decrease in COP observed with LRS administration. No differences between treatments were detected for blood glucose, lactate, total proteins and electrolytes. Packed cell volume was lower with the H group immediately after finishing HES-administration and for an additional 30 min. In all horses, all blood biochemical variables other than lactate returned to normal after 12 h. No clinically relevant differences between treatments were detected for cardiopulmonary variables, although 23.1% of the NH-horses needed rescue-HES to maintain cardiovascular function, while none of the H-horses needed additional colloids. Overall, 6 mL/kg HES (200/0.5) was found to be effective in maintaining COP during anaesthesia in systemically healthy horses. Intermediate and long-term effects were below the limit of detection. The potentially beneficial effects on cardiovascular function need further investigation, especially in critically ill horses.