PREVENTION OF THE FLUID-ELECTROLYTE “PROBLEM” BY SIMPLE MEANS

Proper fluid balance may be maintained in patients after operation by the employment of simple, inexpensive procedures which may be carried out even in the smallest hospitals.Daily weighing of patients, measurement of fluid intake and output, and knowledge of the probable electrolyte content of fluid losses are adequate guides for replacement of fluids and electrolytes. An increase in body weight is a warning of overhydration.The content of the solution used for replacement is dictated by the route of fluid output—whether from the gastrointestinal tract, the skin, or the kidneys. Insensible losses (by perspiration and respiration) are fairly static.Except to replace extrarenal losses, parenteral administration of normal saline solution in the immediate postoperative period is contraindicated.Mistakes in replacement methods, especially those causing overhydration, are particularly hazardous for elderly patients.     

Body Water and Electrolyte Composition in Acute Renal Failure

Body water and electrolyte contents have been measured by means of muscle biopsy analysis in 11 patients with untreated acute renal failure and in one patient during the diuretic recovery phase of his illness. Patients with acute oliguric renal failure show two main types of imbalance. One group shows evidence of a reduction in extracellular sodium and chloride with normal intracellular water and electrolytes. These findings are thought to be due to a combination of excess urinary salt loss during the development of oliguric renal failure, and inadequate replacement of extrarenal electrolyte losses. A second group shows overhydration of both extra- and intracellular phases, associated with an excess of sodium and chloride. The intracellular potassium concentration is reduced, owing to the intracellular water excess. The patient studied during the diuretic recovery phase of acute renal failure showed a marked loss of sodium and chloride, which emphasizes the necessity to replace urinary electrolyte losses at this stage of the illness. It is often extremely difficult to assess fluid and electrolyte balance in patients presenting with acute renal failure, and muscle biopsy analysis or isotope dilution studies may be required before accurate replacement therapy is possible.     

Nutritional needs for exercise in the heat

Although hot conditions are not typically conducive to optimal sports performance, nutritional strategies play an important role in assisting an athlete to perform as well as possible in a hot environment. A key issue is the prevention of hypohydration during an exercise session. Fluid intake strategies should be undertaken in a cyclical sequence: hydrate well prior to the workout, drink as much as is comfortable and practical during the session, and rehydrate aggressively afterwards in preparation for future exercise bouts. There is some interest in hyperhydration strategies, such as hyperhydration with glycerol, to prepare the athlete for a situation where there is little opportunity for fluid intake to match large sweat losses. Recovery of significant fluid losses after exercise is assisted by the simultaneous replacement of electrolyte losses. Carbohydrate (CHO) requirements for exercise are increased in the heat, due to a shift in substrate utilization towards CHO oxidation. Daily food patterns should focus on replacing glycogen stores after exercise, and competition strategies should include activities to enhance CHO availability, such as CHO loading for endurance events, pre-event CHO intake, and intake of sports drinks in events lasting longer than 60 min. Although CHO ingestion may not enhance the performance of all events undertaken in hot weather, there are no disadvantages to the consumption of beverages containing 4-8% CHO and electrolytes. In fact, the palatability of these drinks may enhance the voluntary intake of fluid. Although there is some evidence of increased protein catabolism and cellular damage due to production of oxygen radicals during exercise in the heat, there is insufficient evidence to make specific dietary recommendations to account for these issues.     

ITO‐Free and Fully Solution‐Processed Semitransparent Organic Solar Cells with High Fill Factors

Organic photovoltaic (OPV) solar cells that can be simply processed from solution are in the focus of the academic and industrial community because of their enormous potential to reduce cost. One big challenge in developing a fully solution‐processed OPV technology is the design of a well‐performing electrode system, allowing the replacement of ITO. Several solution‐processed electrode systems were already discussed, but none of them could match the performance of ITO. Here, we report efficient ITO‐free and fully solution‐processed semitransparent inverted organic solar cells based on silver nanowire (AgNW) electrodes. To demonstrate the potential of these AgNW electrodes, they were employed as both the bottom and top electrodes. Record devices achieved fill factors as high as 63.0%, which is comparable to ITO based reference devices. These results provide important progress for fully printed organic solar cells and indicate that ITO‐free, transparent as well as non‐transparent organic solar cells can indeed be fully solution‐processed without losses.     

Overhydration,Cardiac Function and Survival in Hemodialysis Patients

Background and objectives

Chronic subclinical volume overload occurs very frequently and may be ubiquitous in hemodialysis (HD) patients receiving the standard thrice-weekly treatment. It is directly associated with hypertension, increased arterial stiffness, left ventricular hipertrophy, heart failure, and eventually, higher mortality and morbidity. We aimed to assess for the first time if the relationship between bioimpedance assessed overhydration and survival is maintained when adjustments for echocardiographic parameters are considered.

Design, setting, participants and measurements

A prospective cohort trial was conducted to investigate the impact of overhydration on all cause mortality and cardiovascular events (CVE), by using a previously reported cut-off value for overhydration and also investigating a new cut-off value derived from our analysis of this specific cohort. The body composition of 221 HD patients from a single center was assessed at baseline using bioimpedance. In 157 patients supplemental echocardiography was performed (echocardiography subgroup). Comparative survival analysis was performed using two cut-off points for relative fluid overload (RFO): 15% and 17.4% (a value determined by statistical analysis to have the best predictive value for mortality in our cohort).

Results

In the entire study population, patients considered overhydrated (using both cut-offs) had a significant increased risk for all-cause mortality in both univariate (HR = 2.12, 95%CI = 1.30–3.47 for RFO>15% and HR = 2.86, 95%CI = 1.72–4.78 for RFO>17.4%, respectively) and multivariate (HR = 1.87, 95%CI = 1.12–3.13 for RFO>15% and HR = 2.72, 95%CI = 1.60–4.63 for RFO>17.4%, respectively) Cox survival analysis. In the echocardiography subgroup, only the 17.4% cut-off remained associated with the outcome after adjustment for different echocardiographic parameters in the multivariate survival analysis. The number of CVE was significantly higher in overhydrated patients in both univariate (HR = 2.46, 95%CI = 1.56–3.87 for RFO >15% and HR = 3.67, 95%CI = 2.29–5.89 for RFO >17.4%) and multivariate (HR = 2.31, 95%CI = 1.42–3.77 for RFO >15% and HR = 4.17, 95%CI = 2.48–7.02 for RFO >17.4%) Cox regression analysis.

Conclusions

The study shows that the hydration status is associated with the mortality risk in a HD population, independently of cardiac morphology and function. We also describe and propose a new cut-off for RFO, in order to better define the relationship between overhydration and mortality risk. Further studies are needed to properly validate this new cut-off in other HD populations.     

Effect of starvation on tissue and serum gluconeogenic enzymes, alkaline phosphatase and tissue glycogen in the freshwater catfish, Heteropneustes fossilis (Bloch).

The influence of starvation has been studied on tissue and serum G-6Pase F-D-Pase and alkaline phosphatase activities and on the muscle and liver glycogen content of the freshwater catfish H. fossilis (Bloch). A marked increase in G-6Pase and F-D-Pase activities and a fall in the muscle and liver glycogen content recorded during 40 day starvation. The rise in gluconeogenic enzymes during starvation may be due to glucocorticoid stimulation. Alkaline phosphatase activity was found to decline markedly during starvation. The decline in enzyme activity is attributed to some factors like a fall in the rate of synthesis caused by lowered metabolic demands and to electrolyte imbalance caused by tissue overhydration. The fall in glycogen content may be related to the starved condition of the fish. Elevation in glycogen content and alkaline phosphatase activity and a fall in gluconeogenic enzymes were noted when feeding had been resumed.     

Electrolyte balance in gastrointestinal disease

Even small losses of gastrointestinal secretions when combined with reduced intake of electrolytes may seriously disturb electrolyte balance. Knowledge of the ionic composition of secretions lost is essential in planning therapy. Loss of gastric contents usually results in excessive loss of chloride; in achlorhydria this is not the case. Loss of sodium and potassium may be large in either case and is often underestimated. Small bowel obstruction results in a more balanced loss of electrolyte which may not affect acidbase balance greatly. In diarrhea loss of base predominates, and may result in a large potassium deficit. Steatorrhea due to nontropical sprue results in large fecal losses of sodium, potassium and chloride, in addition to the large calcium and phosphorus loss. In chronic peptic ulcer excessive ingestion of milk and absorbable alkalies may result in hypercalcemia, azotemia and alkalosis, without hypercalciuria. Since renal function is usually adequate in the milder gastrointestinal disturbances, electrolyte and fluid replacement should be started early, and can be guided by generally available laboratory tests, the carbon dioxide combining power and serum chloride levels, provided the predominate ionic loss is known and potassium deficiency remedied. If this is done, development of serious fluid and electrolyte deficits can usually be prevented.     

Isolation of rat trachea interstitial fluid and demonstration of local cytokine production in lipopolysaccharide-induced systemic inflammation.

Access to interstitial fluid from trachea is important for understanding tracheal microcirculation and pathophysiology. We tested whether a centrifugation method could be applied to isolate this fluid in rats by exposing excised trachea to G forces up to 609 g. The ratio between the concentration of the equilibrated extracellular tracer 51Cr-labeled EDTA in fluid isolated at 239 g and plasma averaged 0.94 +/- 0.03 (n = 14), suggesting that contamination from the intracellular fluid phase was negligible. The protein pattern of the isolated fluid resembled plasma closely and had a protein concentration 83% of that in plasma. The colloid osmotic pressure in the centrifugate in controls (n = 5) was 18.8 +/- 0.6 mmHg with a corresponding pressure in plasma of 22 +/- 1.5 mmHg, whereas after overhydration (n = 5) these pressures fell to 9.8 +/- 0.4 and 11.9 +/- 0.4 mmHg, respectively. We measured inflammatory cytokine concentration in serum, interstitial fluid, and bronchoalveolar lavage fluid in LPS-induced inflammation. In control animals, low levels of IL-1 beta, IL-6, and TNF-alpha in serum, trachea interstitial fluid, and bronchoalveolar lavage fluid were detected. LPS resulted in a significantly higher concentration in IL-1 beta and IL-6 in interstitial fluid than in serum, showing a local production. To conclude, we have shown that interstitial fluid can be isolated from trachea by centrifugation and that trachea interstitial fluid has a high protein concentration and colloid osmotic pressure relative to plasma. Trachea interstitial fluid may also reflect lower airways and thus be of importance for understanding, e.g., inflammatory-induced airway obstruction.     

Monitoring the critically ill surgical patient.

Critically ill surgical patients account for approximately half the patients in an active multidisciplinary critical care unit. Hypovolemia and sepsis are common in such patients and affect a number of organ systems. Monitoring these systems provides therapeutically relevant information that may decrease morbidity and improve patient survival. Circulatory hemodynamics may be assessed by direct measurement of the arterial blood pressure, central venous and pulmonary artery pressure monitoring and cardiac output determination; the data thus obtained are valuable in guiding fluid replacement in the hypovolemic individual. The respiratory status may be assessed by bedside spirometry and measurement of arterial blood gas tensions to gauge pulmonary function and the need for assisted ventilation. Renal dysfunction is common in such patients; careful analysis of both urine and blood may identify prerenal as opposed to renal and postrenal factors. Monitoring of the gastrointestinal tract, especially for hemorrhage, is important. Finally, careful attention to nutritional status and provision of adequate protein and energy intake by mouth or by vein is a vital component of the optimal care of these patients.     

Review and Meta‐analysis of Pharmacotherapy for Binge‐eating Disorder

This study evaluated available controlled treatment studies to determine utility of pharmacotherapy for binge‐eating disorder (BED). The authors identified randomized placebo‐controlled trials testing pharmacotherapy‐only treatments and controlled trials testing pharmacotherapy with psychotherapy treatments. Meta‐analysis was performed on placebo‐controlled trials with data for attrition, remission, and weight loss. Qualitative review was performed on remaining controlled treatment literature. A total of 33 studies were considered of which 14 studies with a total of 1,279 patients were included in the meta‐analysis of pharmacotherapy‐only treatment and 8 studies with a total of 683 patients were included in the qualitative review of pharmacotherapy combined with psychotherapy interventions. No evidence suggested significant differences between medication and placebo for attrition. Evidence suggested that pharmacological treatments have a clinically significant advantage over placebo for achieving short‐term remission from binge eating (48.7% vs. 28.5%) and for weight loss, although weight losses are not substantial. No data exist to allow evaluation of longer‐term effects of pharmacotherapy‐only treatment for BED. Combining medications with psychotherapy interventions failed to significantly enhance binge outcomes, although specific medications (orlistat, topiramate) enhanced weight losses achieved with cognitive behavioral therapy and behavioral weight loss. In summary, BED patients can be advised that certain pharmacotherapies may enhance likelihood of stopping binge eating short term, but that longer‐term effects are unknown. Although some weight loss may occur, it is unlikely to be substantial with available medications. Combining medications with cognitive or behavioral treatments is unlikely to enhance binge outcomes, but specific medications (orlistat, topiramate) may enhance weight losses, albeit modestly.     

Infantile diarrhea; tolerance to solutions of electrolytes by mouth

Since Darrow's recommendation of electrolyte administration by mouth to infants with diarrhea, the constituting of a palatable liquid has been in the minds of all persons concerned with the treatment of diarrhea. Owing to the frequent association of gastric distress with oral administration of electrolyte solution, presumably because of increased osmolarity, a study was made at Kern County General Hospital to determine what osmolarity of solution was tolerated by most infants. For this purpose a commercially prepared oral electrolyte solution was used. When this new solution was given undiluted-that is, at an osmolarity of 20 times that of physiologic solution-only one of 29 patients, who were acutely ill and dehydrated, refused it or vomited it, probably due to irritation of the gastric mucosa. However, at a dilution of 1:3 with 5 per cent glucose and an osmolarity of six times physiological, only one of the 29 infants vomited and two others occasionally refused it. The length of hospital stay was not shortened by the substitution of the commercial preparation in either dilution. However, since the babies readily drank this electrolyte solution, it was possible to stop parenteral administration of electrolytes once fluid replacement had been carried out when the patient was first admitted.     

A 10-year experience in the treatment of intraabdominal cerebrospinal fluid pseudocysts

The aim of this retrospective study was to assess a ten-year experience in the treatment of rare complications of ventriculoperitoneal shunting--intraabdominal cerebrospinal fluid pseudocysts. At this time there are no data about incidence, clinical course and treatment of these complications in Croatia. Cerebrospinal fluid (CSF) abdominal pseudocyst is an uncommon but important complication of ventriculoperitoneal shunts. Retrospective data were obtained from 5 children with abdominal CSF pseudocysts, treated between 1996 and 2007. The incidence of intraabdominal CSF pseudocysts in our study is 2.9%. All patients were girls ranged in age from 4 to 12 years old (mean 8.8 years). In most cases etiology of hydrocephalus was congenital, idiopathic. Abdominal pain and distension were the most frequent clinical finding (4/5). Although infection has been reported as responsible for pseudocyst formation, we did not found it in our series. Laparotomy with cyst wall excision and catheter replacement was performed in 2/5 cases, and only cyst fluid aspiration with catheter replacement in 3/5 cases. Recurrence of the abdominal cyst was observed in one girl who was in terminal stadium of anaplastic ependymoma. It is our opinion that only catheter replacement and cyst fluid evacuation, as one of the treatment modalities, may be successful, even in large CSF intraperitoneal pseudocysts.     

Preliminary observations on the association between serum IL-6 and hydration status and cardiovascular risk in patients treated with peritoneal dialysis

IntroductionSystemic inflammation, as defined by elevated blood IL-6, is a strong independent predictor of peritoneal dialysis (PD) patient survival. The present study has aimed to determine whether there exists a particular “phenotype” associated with high systemic IL-6 that characterizes PD patients in terms of their fluid status and cardiac parameters.MethodsFifty-seven prevalent PD patients were classified according to serum concentrations of IL-6. The degree of overhydration was assessed by bioimpedance analysis (BIA). Echocardiography and serum concentrations of NT-proBNP and troponin T were used to assess cardiovascular risk.ResultsPatients with high serum IL-6 were older, more often diabetic, treated with PD for longer, and significantly more overhydrated. There was a significant correlation between serum IL-6, hydration status (r = 0.38; p = 0.002) and serum albumin (r = −0.35; p = 0.009). Multivariate regression analysis confirmed a strong association of overhydration, hypoalbuminemia, and systemic IL-6 concentration. Patients with high IL-6 had significantly increased levels of both NT-proBNP (r = 0.36; p = 0.006) and TnT (r = 0.50; p < 0.001) in the absence of abnormalities in echocardiography.ConclusionsHigh systemic IL-6 identifies PD patients with increased cardiovascular risk that is significantly related to overhydration. Thus, the measurement of serum IL-6 may contribute to the more accurate assessment of cardiovascular status in patients undergoing PD.     

Fluid transport by airway epithelia

Airway epithelia possess transepithelial ion transport processes which may help to regulate the fluid content of airway secretions. Chloride secretion promotes fluid movement from blood to airway lumen. Active absorption of Na favours fluid movement in the opposite direction. The balance between these two processes can be altered by a number of agents which stimulate Cl secretion. The importance of ion transport for normal mucociliary clearance is suggested by the finding that airway epithelia in patients with cystic fibrosis are unable to secrete chloride. This defect may cause the characteristically sticky and tenacious mucous secretions which are the major cause of death in this disease.     

HYPERNATREMIA—Its Significance in Pediatric Practice

Hypernatremic dehydration is a fairly common and potentially very dangerous illness in infants and children. It occurs during the course of a wide variety of illnesses.Predisposing factors include central nervous system diseases, decreased fluid intake, increased fluid losses from hyperventilation, perspiring, diarrhea and emesis, increased aldosterone output (contributing to sodium retention), the infant''s high obligatory renal water loss and the practice of feeding infants fluids with a comparatively high solute content.If the attending physician is aware of the predisposing factors and makes an early diagnosis and then rehydrates the patient slowly using solutions which contain some salt, the outcome will most likely be favorable. Even though the brain appears to be damaged during rehydration, the patient may make a complete recovery if proper supportive measures are instituted.     

Multiorgan dysfunction syndrome: how water might contribute to its progression

Mulitorgan dysfunction syndrome (MODS) is one of the most frequent conditions encountered in intensive-care medicine. MODS is defined as total r partial loss oftwo or more organs with vital functions. The development of acute renal failure (ARF) in MODS leads to an additional aggravation with considerably higher hospital mortality than in other ICU patients with MODS. Whereas dissolved substances involved in the regulation of regional blood flow, endothelial cell injury, microvascular permeability, oxygnation, and nutrition of cells are at the focus of interest in MODS, hardly any scientific attention is paid to their main solvent water. An impaired renal water excretion and an icreased metabolic water volunme requiring exceetion interfere with diffusive and convective oxygen transport through the different fluid compartments. It will be shown first that the ratio of U_osm/P_osm appears to be a reliable tools to assess overhydration in ARF. Secondly, the limits of urinary output in response to water intake will be considered. Furthermore, the metabolic water formation by an enhanced degradation of endogenous protein and fat will be discussed. Finally, the daily caloric intake is questioned with respect to energy expenditure and metabolic water formation.     

Optimizing a rotor‐stator filter matrix for high‐gradient magnetic separation of functionalized magnetic particles

The processing of wines with enzymes is a process chain in which losses of biocatalyst are unavoidable. A promising technique for the minimization of these losses and for the reduction of processing time is the high‐gradient magnetic separation in combination with enzymes, which are immobilized onto functionalized magnetic particles. When magnetizable particles are used and magnetic separation is applied to separate these particles from nonmagnetizable particles and solutes, the enzymes can be recycled and used for several production batches. The magnetic filter used in this study had a filter matrix with concentrically stacked circular rotor and stator plates which are arranged in an alternating order. Different geometries of the filter plate notches were examined to optimize the reproducibility of particle retention. In computational fluid dynamic studies, the influence of the notch geometries on the shear rate generation was analyzed for the rinsing procedure. Separation experiments with an optimized geometry of the filter plates were carried out in water and white wine suspensions.     

Sodium-free fluid ingestion decreases plasma sodium during exercise in the heat.

This study assessed whether replacing sweat losses with sodium-free fluid can lower the plasma sodium concentration and thereby precipitate the development of hyponatremia. Ten male endurance athletes participated in one 1-h exercise pretrial to estimate fluid needs and two 3-h experimental trials on a cycle ergometer at 55% of maximum O2 consumption at 34 degrees C and 65% relative humidity. In the experimental trials, fluid loss was replaced by distilled water (W) or a sodium-containing (18 mmol/l) sports drink, Gatorade (G). Six subjects did not complete 3 h in trial W, and four did not complete 3 h in trial G. The rate of change in plasma sodium concentration in all subjects, regardless of exercise time completed, was greater with W than with G (-2.48 +/- 2.25 vs. -0.86 +/- 1.61 mmol. l-1. h-1, P = 0.0198). One subject developed hyponatremia (plasma sodium 128 mmol/l) at exhaustion (2.5 h) in the W trial. A decrease in sodium concentration was correlated with decreased exercise time (R = 0.674; P = 0.022). A lower rate of urine production correlated with a greater rate of sodium decrease (R = -0. 478; P = 0.0447). Sweat production was not significantly correlated with plasma sodium reduction. The results show that decreased plasma sodium concentration can result from replacement of sweat losses with plain W, when sweat losses are large, and can precipitate the development of hyponatremia, particularly in individuals who have a decreased urine production during exercise. Exercise performance is also reduced with a decrease in plasma sodium concentration. We, therefore, recommend consumption of a sodium-containing beverage to compensate for large sweat losses incurred during exercise.     

Environmental Sustainability of Fluid Milk Delivery Systems in the United States

Beverage producers in the United States choose packaging based on cost and consumer preference. Monolayer high‐density polyethylene (HDPE) and gable‐top carton containers have long dominated the U.S. fluid milk market, but pressure for more sustainable packaging is increasing. We present a broad discussion on environmental sustainability of 18 fluid milk containers through life cycle assessment. Because different container types require unique milk processing, distribution, and disposal and incur or avoid milk losses, fluid milk delivery systems (FMDSs) are evaluated, rather than containers in isolation. By assessing FMDSs, a complete measure of containers’ environmental sustainability was obtained. Despite conservative assumptions about milk losses, differences in container size, milk processing, distribution, and container recycling, pair‐wise cradle‐to‐grave comparisons of FMDSs show there are no superior FMDSs. But, 500‐ to 1,000‐milliliter FMDSs are potentially superior to ≥half gallon if they prevent milk losses. Thus, the future of FMDSs in the United States depends on the industry's ability to prevent distribution (12%) and consumption milk losses (20% to 35%). Farm‐gate‐to‐grave comparisons showed that chilled HDPE FMDSs are superior to other plastic and chilled paperboard FMDSs for climate‐change impact, but the result is inconclusive for chilled HDPE to ambient (unrefrigerated) paperboard or plastic pouch FMDS comparisons. Plastic pouch FMDSs show potential to reduce nonrenewable fossil energy, but need to be recyclable. Ambient FMDSs are superior to chilled FMDSs for water depletion. Eight‐ounce paperboard FMDSs are superior to 8‐ounce plastic FMDSs. Thus, alternative FMDSs may improve environmental sustainability of the U.S. postfarm fluid milk supply chain.     

Water and electrolyte shifts with partial fluid replacement during exercise

In this study, we examined whether athletes, who typically replace only approximately 50% of their fluid losses during moderate-duration endurance exercise, should attempt to replace their Na+ losses to maintain extracellular fluid volume. Six male cyclists performed three 90-min rides at 65% of peak O2 uptake in a 32 degrees C environment and ingested either no fluid (NF), 1.21 of water (W), or saline (S) containing 100 mmol of NaCl x l(-1) to replace their electrolyte losses. Both W and S conditions decreased final heart rates by approximately 10 betas min(-1) (P<0.005) and reduced falls in plasma volume (PV) by approximately 4% (P<0.05). Maintenance of PV after 10 min in the W trial prevented further rises in plasma concentrations of Na+ [Na+], Cl- and protein but in the S and NF trials, plasma [Na+] continued to increase by approximately 4 mEq x l(-1). Differences in plasma [Na+] had little effect on the approximately 2.4 l fluid, approximately 120 mEq Na+ and approximately 50 mEq K+ losses in sweat and urine in the three trials. The main effects of W and S were on body fluid shifts. During the NF trial, PV and interstitial fluid (ISF) and intracellular fluid (ICF) volumes decreased by approximately 0.1, 1.2 and 1.0 l, respectively. In the W trial, the approximately 1.2 l fluid and approximately 120 mEq Na+ losses contracted the ISF volume, and in the S trial, ISF volume was maintained by the movement of water from the ICF. Since the W and S trials were equally effective in maintaining PV, Na+ ingestion may not be of much advantage to athletes who typically replace only approximately 50% of their fluid losses during competitive endurance exercise.