Effects of Fluid Resuscitation on Cardiovascular Performance After Posttraumatic Pneumonectomy

Background: Several factors have been implicated in the high-mortality rate of posttraumatic pneumonectomy. In this study, we evaluated the hemodynamic and echocardiographic changes induced by pneumonectomy and fluid resuscitation after hemorrhagic shock. Methods: Fourteen dogs were bled to a target mean arterial pressure of 40 mmHg. The animals were assigned to two groups: control (no fluid resuscitation) and lactated Ringer`s (3 x shed blood volume). The left pulmonary hilum was cross clamped, and the animals were observed for 60 minutes. Systemic hemodynamics was evaluated using Swan-Ganz, arterial catheter, and ultrasonic flow probe. Systemic O(2)-derived variables were calculated. Ejection fraction was determined by two-dimensional echocardiography. Results: Fluid resuscitation improved the mean arterial pressure and systemic oxygen delivery. After pneumonectomy, no significant increase in right ventricular pressure was observed in the LR group. No signs of major ventricular dilation or changes in arterial oxygenation were observed. Conclusion: Our data suggest that pneumonectomy is not associated with early pulmonary hypertension; gentle fluid resuscitation improves cardiovascular performance and is not associated with an increase in right ventricular pressure.

NMR imaging of fluid pathways during drainage of softwood in a pressure membrane chamber

An experiment was implemented to study fluid flow in a pressure media. This procedure successfully combines nuclear magnetic resonance imaging with a pressure membrane chamber in order to visualize the non-wetting and wetting fluid flows with controlled boundary conditions. A specially designed pressure membrane chamber, made of non-magnetic materials and able to withstand 4 MPa, was designed and built for this purpose. These two techniques were applied to the drainage of Douglas fir sapwood. In the study of the longitudinal flow, narrow drainage fingers are formed in the latewood zones. They follow the longitudinal direction of wood and spread throughout the sample length. These fingers then enlarge in the cross-section plane and coalesce until drainage reaches the whole latewood part. At the end of the experiments, when the drainage of liquid water in latewood is completed, just a few sites of percolation appear in earlywood zones. This difference is a result of the wood anatomical structure, where pits, the apertures that allow the sap to flow between wood cells, are more easily aspirated in earlywood than in latewood. (C) 2007 Elsevier Ltd. All rights reserved.

Effectiveness of the CAGE questionnaire, gamma-glutamyltransferase and mean corpuscular volume of red blood cells as markers for alcohol-related problems in the workplace

Objective: To evaluate the usefulness of gamma-glutamyltransferase (GGT) and mean corpuscular volume (MCV), as well as that of the CAGE questionnaire, in workplace screening for alcohol abuse/dependence. Methods: A total of 183 male employees were submitted to structured interviews (Structured Clinical Interview for DSM-IV 2.0 and CAGE questionnaire). Blood samples were collected. Diagnostic accuracy and odds ratio were determined for the CAGE, GGT and MCV. Results: The CAGE questionnaire presented the best sensitivity for alcohol dependence (91%; specificity, 87.8%) and for alcohol abuse (87.5%, specificity, 80.9%), which increased when the questionnaire was used in combination with GGT (sensitivity, 100% and 87.5%, respectively; specificity, 68% and 61.5, respectively). CAGE positive results and/or alterations in GGT were less likely to occur among employees not presenting alcohol abuse/ dependence than among those presenting such abuse (OR for CAGE = 13, p < 0.05; OR for CAGE-GGT = 11, p < 0.05) or dependence (OR for CAGE = 76, p < 0.0 1; OR for GGT = 5, p < 0.0 1). Employees not presenting alcohol abuse/dependence were also several times more likely to present negative CAGE or GGT results. Conclusions: The use short, simple questionnaires, combined with that of low-cost biochemical markers, such as GGT, can serve as an initial screening for alcohol-related problems, especially for employees in hazardous occupations. The data provided can serve to corroborate clinical findings. (C) 2008 Elsevier Ltd. All rights reserved.

EFFECT OF FLUID AND FOOD INTAKE ON THE BODY COMPOSITION EVALUATION OF ELDERLY PERSONS

Background: Several studies have shown that liquid and food intake interfere with the evaluation of body composition in adults. However, since there are no reports about this interference in the elderly population, the need to fast for this evaluation may be dispensable. Objectives: The objective of the present study was to assess the influence of liquid and solid food on the measurement of body composition by bioelectrical impedance analysis (BIA) and by dual energy X-ray absorptiometry (DXA). Design: Forty-one male volunteers aged 62 to 87 years participated in the study. The subjects were submitted to evaluation of body composition by DXA and BIA under fasting conditions and 1 hour after the ingestion of breakfast (500 ml of orange juice and one 50 g bread roll with butter). Results: There was no significant difference in the variables fat-free mass (FFM) or fat mass (FM) between the fasting condition and the evaluation performed 1 hour after the meal as measured by BIA or DXA. There was also no significant difference when the same variables were compared between methods. Conclusion: In the present study, the ingestion of 500 ml orange juice and of one bread roll with butter by elderly subjects did not affect the results of the parameters of body composition determined by BIA or DXA. Thus, these exams could be performed without the rigor of fasting, often poorly tolerated by the elderly.

Influence of Fluid Concentration on the Elevation of Boiling Point of Blackberry Juice

The rise in boiling point of blackberry juice was experimentally measured at soluble solids concentrations in the range of 9.4 to 58.4Brix and pressures between 4.9 103 and 9.0 104 Pa (abs.). Different approaches to representing experimental data, including the Duhring`s rule, a model similar to Antoine equation and other empirical models proposed in the literature were tested. In the range of 9.4 to 33.6Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 39.1Brix. Experimental data could be best predicted by adjusting an empirical model, which consists of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration.

Improvements in the 6-Min Walk Test and Spirometry Following Thoracentesis for Symptomatic Pleural Effusions

Background: Impairment in pulmonary capacity due to pleural effusion compromises daily activity. Removal of fluid improves symptoms, but the impact, especially on exercise capacity, has not been determined. Methods: Twenty-five patients with unilateral pleural effusion documented by chest radiograph were included. The 6-min walk test, Borg modified dyspnea score, FVC, and FEV, were analyzed before and 48 h after the removal of large pleural effusions. Results: The mean fluid removed was 1,564 +/- 695 mL. After the procedure, values of FVC, FEV and 6-min walk distance increased (P<.001), whereas dyspnea decreased (P<.001). Statistical correlations (P<.001) between 6-min walk distance and FVC (r=0.725) and between 6-min walk distance and FEV, (r=0.661) were observed. Correlations also were observed between the deltas (prethoracentesis X postthoracentesis) of the 6-min walk test and the percentage of FVC (r=0.450) and of FEV, (r=0.472) divided by the volume of fluid removed (P<.05). Conclusion: In addition to the improvement in lung function after thoracentesis, the benefits of fluid removal are more evident in situations of exertion, allowing better readaptation of patients to routine activities. CHEST 2011; 139(6):1424-1429

An unstructured CVFEM and moving interface algorithm for non-Newtonian Hele-Shaw flows in injection molding

Purpose - The purpose of this paper is to develop a novel unstructured simulation approach for injection molding processes described by the Hele-Shaw model. Design/methodology/approach - The scheme involves dual dynamic meshes with active and inactive cells determined from an initial background pointset. The quasi-static pressure solution in each timestep for this evolving unstructured mesh system is approximated using a control volume finite element method formulation coupled to a corresponding modified volume of fluid method. The flow is considered to be isothermal and non-Newtonian. Findings - Supporting numerical tests and performance studies for polystyrene described by Carreau, Cross, Ellis and Power-law fluid models are conducted. Results for the present method are shown to be comparable to those from other methods for both Newtonian fluid and polystyrene fluid injected in different mold geometries. Research limitations/implications - With respect to the methodology, the background pointset infers a mesh that is dynamically reconstructed here, and there are a number of efficiency issues and improvements that would be relevant to industrial applications. For instance, one can use the pointset to construct special bases and invoke a so-called ""meshless"" scheme using the basis. This would require some interesting strategies to deal with the dynamic point enrichment of the moving front that could benefit from the present front treatment strategy. There are also issues related to mass conservation and fill-time errors that might be addressed by introducing suitable projections. The general question of ""rate of convergence"" of these schemes requires analysis. Numerical results here suggest first-order accuracy and are consistent with the approximations made, but theoretical results are not available yet for these methods. Originality/value - This novel unstructured simulation approach involves dual meshes with active and inactive cells determined from an initial background pointset: local active dual patches are constructed ""on-the-fly"" for each ""active point"" to form a dynamic virtual mesh of active elements that evolves with the moving interface.

Online monitoring of pulse pressure variation to guide fluid therapy after cardiac surgery

BACKGROUND: The arterial pulse pressure variation induced by mechanical ventilation (Delta PP) has been shown to be a predictor of fluid responsiveness. Until now, Delta PP has had to be calculated offline (from a computer recording or a paper printing of the arterial pressure curve), or to be derived from specific cardiac output monitors, limiting the widespread use of this parameter. Recently, a method has been developed for the automatic calculation and real-time monitoring of Delta PP using standard bedside monitors. Whether this method is to predict reliable predictor of fluid responsiveness remains to be determined. METHODS: We conducted a prospective clinical study in 59 mechanically ventilated patients in the postoperative period of cardiac surgery. Patients studied were considered at low risk for complications related to fluid administration (pulmonary artery occlusion pressure <20 mm Hg, left ventricular ejection fraction >= 40%). All patients were instrumented with an arterial line and a pulmonary artery catheter. Cardiac filling pressures and cardiac output were measured before and after intravascular fluid administration (20 mL/kg of lactated Ringer`s solution over 20 min), whereas Delta PP was automatically calculated and continuously monitored. RESULTS: Fluid administration increased cardiac output by at least 15% in 39 patients (66% = responders). Before fluid administration, responders and nonresponders were comparable with regard to right atrial and pulmonary artery occlusion pressures. In contrast, Delta PP was significantly greater in responders than in nonresponders, (17% +/- 3% vs 9% +/- 2%, P < 0.001). The Delta PP cut-off value of 12% allowed identification of responders with a sensitivity of 97% and a specificity of 95%. CONCLUSION: Automatic real-time monitoring of Delta PP is possible using a standard bedside rnonitor and was found to be a reliable method to predict fluid responsiveness after cardiac surgery. Additional studies are needed to determine if this technique can be used to avoid the complications of fluid administration in high-risk patients.

A Comparison Between Pulse Pressure Variation and Right End Diastolic Volume Index as Guides to Resuscitation in a Model of Hemorrhagic Shock in Pigs

Background: Different hemodynamic parameters including static indicators of cardiac preload as right ventricular end-diastolic volume index (RVEDVI) and dynamic parameters as pulse pressure variation (PPV) have been used in the decision-making process regarding volume expansion in critically ill patients. The objective of this study was to compare fluid resuscitation guided by either PPV or RVEDVI after experimentally induced hemorrhagic shock. Methods: Twenty-six anesthetized and mechanically ventilated pigs were allocated into control (group I), PPV (group II), or RVEDVI (group III) group. Hemorrhagic shock was induced by blood withdrawal to target mean arterial pressure of 40 mm Hg, maintained for 60 minutes. Parameters were measured at baseline, time of shock, 60 minutes after shock, immediately after resuscitation with hydroxyethyl starch 6% (130/0.4), 1 hour and 2 hours thereafter. The endpoint of fluid resuscitation was determined as the baseline values of PPV and RVEDVI. Statistical analysis of data was based on analysis of variance for repeated measures followed by the Bonferroni test (p < 0.05). Results: Volume and time to resuscitation were higher in group III than in group II (group III = 1,305 +/- 331 mL and group II = 965 +/- 245 mL, p < 0.05; and group III = 24.8 +/- 4.7 minutes and group II = 8.8 +/- 1.3 minutes, p < 0.05, respectively). All static and dynamic parameters and biomarkers of tissue oxygenation were affected by hemorrhagic shock and nearly all parameters were restored after resuscitation in both groups. Conclusion: In the proposed model of hemorrhagic shock, resuscitation to the established endpoints was achieved within a smaller amount of time and with less volume when guided by PPV than when guided by pulmonary artery catheter-derived RVEDVI.

HORMONAL RESPONSES TO DIFFERENT RESISTANCE EXERCISE SCHEMES OF SIMILAR TOTAL VOLUME

Uchida, MC, Crewther, BT, Ugrinowitsch, C, Bacurau, RFP, Moriscot, AS, and Aoki, MS. J Strength Cond Res 23(7): 2003-2008, 2009-This study assessed the effect of different resistance exercise scheme (RES) designs of similar total of load lifted on the responses of testosterone, cortisol, and creatine kinase (CK). Twenty-seven healthy males performed 1 of 4 bench press workouts described by the 1 repetition maximum (1RM) load: 4 sets of maximum repetitions at 50%-1RM (50%-1RM RES), 5 sets of maximum repetitions at 75%-1RM (75%-1RM RES), 10 sets of maximum repetitions at 90%-1RM (90%1RM RES), or 8 sets of maximum repetitions at 110%-1RM (110%-1RM RES). Each RES was equated by the total volume of load lifted (repetitions x sets x load). Blood samples, collected pre-exercise (Pre) and post-exercise (Post) at 1 and 24 hours (24 h), were analyzed for total and free testosterone, total cortisol, and CK. In general, testosterone and cortisol showed little change within or between the different RES (p > 0.05), possibly because of the relatively low volume lifted and/ or the small muscle mass activated by the bench press exercise. Cortisol was elevated after the 75%-1RM RES at the Post sample, with this response also exceeding the other RES (p < 0.05). The 24 h CK response was also elevated after the 75%-1RM RES (p < 0.05), thereby suggesting greater training strain for the same volume of load. These results confirm previous recommendations regarding the prescription of resistance exercise and the importance of total volume as a stimulus for activating the endocrine system and achieving long-term adaptation.

Manufacture of ceramic membranes for application in demulsification process for cross-flow microfiltration

This paper describes the manufacture of tubular ceramic membranes and the study of their performance in the demulsification of soybean oil/water emulsions. The membranes were made by iso-static pressing method and micro and macro structurally characterized by SEM, porosimetry by mercury intrusion and determination of apparent density and porosity. The microfiltration tests were realized on an experimental workbench, and fluid dynamic parameters, such as transmembrane flux and pressure were used to evaluate the process relative to the oil phase concentration (analysed by TOC measurements) in the permeate. The results showed that the membrane with pores` average diameter of 1.36 mu m achieved higher transmembrane flux than the membrane with pores` average diameter of 0.8 mu m. The volume of open pores (responsible for the permeation) was predominant in the total porosity, which was higher than 50% for all tested membranes. Concerning demulsification, the monolayer membranes were efficacious, as the rejection coefficient was higher than 99%.

AnSBBR Applied to a Personal Care Industry Wastewater Treatment: Effects of Fill Time, Volume Treated Per Cycle, and Organic Load

A study was performed regarding the effect of the relation between fill time, volume treated per cycle, and influent concentration at different applied organic loadings on the stability and efficiency of an anaerobic sequencing batch reactor containing immobilized biomass on polyurethane foam with recirculation of the liquid phase (AnSBBR) applied to the treatment of wastewater from a personal care industry. Total cycle length of the reactor was 8 h (480 min). Fill times were 10 min in the batch operation, 4 h in the fed-batch operation, and a 10-min batch followed by a 4-h fed batch in the mixed operation. Settling time was not necessary since the biomass was immobilized and decant time was 10 min. Volume of liquid medium in the reactor was 2.5 L, whereas volume treated per cycle ranged from 0.88 to 2.5 L in accordance with fill time. Influent concentration varied from 300 to 1,425 mg COD/L, resulting in an applied volumetric organic load of 0.9 and 1.5 g COD/L.d. Recirculation flow rate was 20 L/h, and the reactor was maintained at 30 A degrees C. Values of organic matter removal efficiency of filtered effluent samples were below 71% in the batch operations and above 74% in the operations of fed batch followed by batch. Feeding wastewater during part of the operational cycle was beneficial to the system, as it resulted in indirect control over the conversion of substrate into intermediates that would negatively interfere with the biochemical reactions regarding the degradation of organic matter. As a result, the average substrate consumption increased, leading to higher organic removal efficiencies in the fed-batch operations.

Effect of specific feed volume on the performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) with circulation treating different wastewaters under different organic loads

The objective of this research was to study the behavior of two anaerobic sequencing batch reactors, containing immobilized biomass (AnSBBR), as a function of the ratio of the volume of treated medium in each cycle to the total volume of reaction medium. The reactors, in which mixing was accomplished by recirculation of the liquid phase, were maintained at 30 +/- 1 degrees C and treated different wastewaters in 8-h cycles. The operational conditions imposed had the objective to investigate whether maintenance of a residual volume in the reactor would affect, at the end of each cycle, process efficiency and stability, as well as to verify the intensity of the effect for different types of wastewaters and organic loading rates. The first reactor, with work volume of 2.5 L, treated reconstituted cheese whey at an organic loading rate of 12 g COD.L(-1).d(-1) and presented similar effluent quality for the four conditions under which it was operated: renewal of 100, 70, 50 and 25 % of its work volume at each cycle. Despite the fact that reduction in the renewed volume did not significantly affect effluent quality, in quantitative terms, this reduction resulted in an increase in the amount of organic matter removed by the first reactor. The second reactor, with work volume of 1.8 L, treated synthetic wastewater at organic loading rates of 3 and 5 g COD.L(-1).d(-1) and operated under two conditions for each loading: renewal of 100 and 50 % of its work volume. At the organic loading rate of 3 g COD.L(-1).d(-1), the results showed that both effluent quality and amount of organic matter removed by the second reactor were independent of the treated volume per cycle. At the organic loading rate of 5 g COD.L(-1).d(-1), although the reduction in the renewed volume did not affect the amount of organic matter removed by the reactor, effluent quality improved during reactor operation with total discharge of its volume. In general, results showed process stability under all conditions, evidencing reactor flexibility and the potential to apply this technology in the treatment of different types of wastewater.

Particle-Image Velocimetry Study of a Pediatric Ventricular Assist Device

Particle-image velocimetry (PIV) was used to visualize the flow within an optically transparent pediatric ventricular assist device (PVAD) under development in our laboratory The device studied is a diaphragm type pulsatile pump with an ejection volume of 30 ml per beating cycle intended for temporary cardiac assistance as a bridge to transplantation or recovery in children. Of particular interest was the identification of flow patterns, including regions of stagnation and/or strong turbulence that often promote thrombus formation and hemolysis, which can degrade the usefulness of such devices. For this purpose, phase-locked PIV measurements were performed in planes parallel to the diaphram that drives the flow in the device. The test fluid was seeded with 10 Am polystyrene spheres, and the motion of these particles was used to determine the instantaneous flow velocity distribution in the illumination plane. These measurements revealed that flow velocities up to 1.0 m/s can occur within the PVAD. Phase-averaged velocity fields revealed the fixed vortices that drive the bulk flow within the device, though significant cycle-to-cycle variability was also quite apparent in the instantaneous velocity distributions, most notably during the filling phase. This cycle-to-cycle variability can generate strong turbulence that may contribute to greater hemolysis. Stagnation regions have also been observed between the input and output branches of the prototype, which can increase the likelihood of thrombus formation. [DOI: 10.1115/1.4001252]

Arterial pulse pressure variation predicting fluid responsiveness in critically ill patients (Retracted article. See vol. 31, pg. 542, 2009)

In critically ill patients, it is important to predict which patients will have their systemic blood flow increased in response to volume expansion to avoid undesired hypovolemia and fluid overloading. Static parameters such as the central venous pressure, the pulmonary arterial occlusion pressure, and the left ventricular end-diastolic dimension cannot accurately discriminate between responders and nonresponders to a fluid challenge. In this regard, respiratory-induced changes in arterial pulse pressure have been demonstrated to accurately predict preload responsiveness in mechanically ventilated patients. Some experimental and clinical studies confirm the usefulness of arterial pulse pressure as a useful tool to guide fluid therapy in critically ill patients.