Assessment of Hydration Status Using Conventional Method and Salivary Osmolarity as a Point-of-care Tool.

Dehydration is a well-known problem worldwide, and its assessment can be challenging due to confusing physical signs. The most effective way to assess hydration status is through the costly stable isotope methodology, but this approach has practical limitations. More commonly accepted and utilized indicators of hydration status are hematological and urinary parameters. However, hematological markers require invasive methods, and urinary markers have varying degrees of success in tracking hydration changes. While alterations in body weight can serve as a means of promptly evaluating hydration status, various factors such as food consumption, fluid intake, fecal losses, and urine production can impact these changes. Researchers have turned their attention to saliva as a potential marker and point-of-care (POC) testing to address the limitations of existing biomarkers. Saliva is appealing due to its easy collection process and similarities to extracellular fluid in terms of water and ion concentrations. Recent studies have shown that saliva flow rate, osmolarity/osmolality, and total protein concentration can effectively monitor changes in body mass during acute dehydration. Misdiagnosing dehydration can have severe clinical consequences, leading to morbidity and even mortality. This narrative review focuses on recognizing the significance of hydration assessment, monitoring, and the potential of salivary osmolarity (SOSM) as an assessment tool. Healthcare professionals can improve their practices and interventions to optimize hydration and promote overall wellness using such tools.

Association of Knowledge and Health Habits with Physiological Hydration Status.

The association of hydration knowledge and health habits with hydration status and fluid intake is rarely examined. We sought to determine whether knowledge or physical health behaviors predict physiological hydration status and fluid intake. Ninety-six participants (59 female; 27 ± 10 year) completed the previously validated hydration survey. Participants then recorded total fluids consumed (TFC), collected urine, and tracked void frequency for 24 h. Hydration status was assessed via 24 h urine specific gravity (USG) and osmolality (Uosm). Health behaviors included self-reported physical activity, BMI, smoking, alcoholic drinking, and sleep status. TFC was significantly correlated with 24 h USG (r = -0.390; p < 0.001), Uosm (r = -0.486; p < 0.001), total urine volume (r = 0.675; p < 0.001), and void frequency (r = 0.518; p < 0.001). Hydration knowledge was not correlated with 24 h USG (r = 0.085; p = 0.420), Uosm (r = 0.087; p = 0.419), urine total volume (r = 0.019; p = 0.857), void frequency (r = 0.030; p = 0.771), or TFC (r = 0.027; p = 0.813). Hydration knowledge did not predict 24 h USG (LR+ = 1.10; LR- = 0.90), Uosm (LR+ = 0.81; LR- = 1.35), or TFC (LR+ = 1.00; LR- = 1.00). Health habits did not predict 24 h USG, Uosm, or TFC. In conclusion, self-reported 24 h diet and fluid log recording is comparable to hydration status verification via 24 h urine collection. Hydration knowledge and health habits are not related to, or predictive of, hydration status.

Plain Water Intake, Sleep Quality, and Hydration Status of Pregnant Woman in Hainan, China: A Cross-Sectional Study.

OBJECTIVE: Both short and long sleep durations are associated with decreased kidney function; however, few studies have examined the relationship between sleep, hydration status, and plain water intake. This study aimed to assess the relationship between sleep quality, hydration status, and plain water intake in pregnant women. METHODS: A cross-sectional study method was used to collect data from 380 pregnant women with regular examinations at the hospital between May 2019 and February 2021. RESULTS: There were statistically significant differences in daily plain water intake (x2 = 14.118, p = 0.001), PSQI score (x2 = 77.708, p < 0.001), sleep duration (x2 = 67.569, p > 0.001), subjective sleep quality (x2 = 67.441, p = 0.001), time to fall asleep (x2 = 64.782, p < 001), sleep disorders (x2 = 70.853, p < 0.001), and daytime dysfunction (x2 = 38.441, p < 0.001) among different hydration status groups. Ordinal logistic regression results indicated that the intake of plain water ≥1500 mL/d (OR = 0.40, 95% CI = 0.24~0.67), good subjective sleep quality (OR = 0.15, 95% CI = 0.07~0.32), short time to fall asleep (OR = 0.32, 95% CI = 0.14~0.70), 8 h of sleep (OR = 0.06, 95% CI = 0.02~0.17), 6-7 h of sleep (OR = 0.19, 95% CI = 0.07~0.54), no sleep disturbance (OR = 0.31, 95% CI = 0.11~0.89), and high sleep efficiency (OR = 0.46, 95% CI = 0.03~0.79) were factors that were correlated with optimal hydration status. Sleep duration and daytime dysfunction partially mediated the effect of plain water intake on hydration status. The mediating effect of sleep duration was -0.036, accounting for 14.006% of the overall effect. The mediating effect of daytime dysfunction was -0.024, accounting for 9.459% of the overall effect. CONCLUSION: The hydration status in pregnant women may be affected by daily plain water intake and sleep quality.

Beverage Consumption and Factors Influencing the Choice of Beverages among Polish Children Aged 11-13 Years in 2018-2023.

Adequate hydration is essential for good health, and an individual's hydration status is determined by the quantity and type of ingested fluids. The aim of the present study was to determine the hydration status of school-age children and evaluate changes in the type and quantity of consumed beverages between 2018 and 2023. The study was conducted in two stages between 2018 and 2023, and a total of 1030 fully completed questionnaires were returned by the children and their parents. A comparison of the parents' responses regarding factors that affect beverage choices revealed that beverage composition was more significant for the parents in 2023 than in 2018, whereas health-promoting properties were significant for only less than 30% of the respondents. Taste preferences were important for both the parents and the children, and they were the main criterion in the choice of beverages in both 2018 and 2023. In turn, advertising was an important factor for children, and the percentage of children who were guided by advertising in their choice of beverages increased from 52.1% in 2018 to 58.5% in 2023 (p < 0.05). Daily fluid intake from beverages in children aged 11-13 years generally does not meet recommended intakes. Low fluid intake can negatively affect children's hydration status and bodily functions. Taste preferences and advertising were correlated with a higher intake of carbonated and non-carbonated sugar-sweetened beverages (SSBs) and dairy beverages. The percentage of children who bought drinks independently and had access to SSBs increased significantly during the analyzed period. Obtain results indicate that nutrition education programs are needed to teach adolescents to make healthy drink choices, limit their consumption of SSBs and EDs, and promote regular intake of natural mineral water and non-sweetened dairy beverages.

Association between Urine Specific Gravity as a Measure of Hydration Status and Risk of Type 2 Diabetes: The Kailuan Prospective Cohort Study.

Diabetes, especially type 2 diabetes (T2D), poses an unprecedented challenge to global public health. Hydration status also plays a fundamental role in human health, especially in people with T2D, which is often overlooked. This study aimed to explore the longitudinal associations between hydration status and the risk of T2D among the Chinese population. This study used data from the large community-based Kailuan cohort, which included adults who attended physical examinations from 2006 to 2007 and were followed until 2020. A total of 71,526 participants who eventually met the standards were divided into five hydration-status groups based on their levels of urine specific gravity (USG). Multivariable and time-dependent Cox proportional hazards models were employed to evaluate the associations of baseline and time-dependent hydration status with T2D incidence. Restricted cubic splines (RCS) analysis was used to examine the dose-response relationship between hydration status and the risk of T2D. Over a median 12.22-year follow-up time, 11,804 of the participants developed T2D. Compared with the optimal hydration-status group, participants with dehydration and severe dehydration had a significantly increased risk of diabetes, with adjusted hazard ratios (95% CI) of 1.30 (1.04-1.63) and 1.38 (1.10-1.74). Time-dependent analyses further confirmed the adverse effects of impending dehydration, dehydration, and severe dehydration on T2D incidence by 16%, 26%, and 33% compared with the reference group. Inadequate hydration is significantly associated with increased risks of T2D among Chinese adults. Our findings provided new epidemiological evidence and highlighted the potential role of adequate hydration status in the early prevention of T2D development.

Energy intake, hydration status, and sleep of world-class male archers during competition.

BACKGROUND: Nutritional intake and sleep, play an important role for recovery and performance in elite sport but little work has been undertaken in archery. The present study aimed to assess energy intake (EI), hydration status, and sleep parameters in world-class male archers over the course of a four-day competition. METHODS: Results, Conclusions Six male, elite-standard archers participated in the study and measurements of hydration status, EI, competition load, and sleep were recorded throughout each day of competition. RESULTS: Daily energy, carbohydrate, and protein intake ranged between 2,563 and 3,986 kcal, 4 and 7.1 g/kg BM, 2.2 and 3.6 g/kg BM per day, respectively. Thus, archers practiced elements of periodized nutrition such that energy and carbohydrate intake was greater on the high-volume competition days (i.e. days 1 and 3; more numbers of arrows, longer duration, and walking distance) in comparison to low-volume days (days 2 and 4) over the tournament (all p > 0.01). Additionally, urine specific gravity was higher after waking, compared to pre- and post-competition, and before bed (all p < 0.05). This indicates that archers were euhydrated pre- and post-competition and before bedtime, while they were slightly hypohydrated after waking up. Sleep data show that disturbances were kept to a minimum. CONCLUSIONS: Collectively, archers appear capable of periodizing their nutritional intake according to daily physical loading during a tournament whilst, staying euhydrated and maintaining sleep quality. In part, such data can help to explain why these archers experience a sustained level of success.

Effects of sex and hydration status on kappa opioid receptor-mediated diuresis in rats.

Understanding the function of the kappa opioid receptor (KOP) is crucial for the development of novel therapeutic interventions that target KOP for the treatment of pain, stress-related disorders and other indications. Activation of KOP produces diuretic effects in rodents and man. Sex is a vital factor to consider when assessing drug response in pre-clinical and clinical studies. In this study, the diuretic effect of the KOP agonist, U50488 (1-10 mg/kg), was investigated in both adult female and male Wistar rats that were either normally hydrated or water-loaded. The KOP antagonist norbinaltorphimine (norBNI, 10 mg/kg) was administered 24 h prior to U50488 to confirm the involvement of KOP. U50488 elicited a significant diuretic response at doses ≥ 3 mg/kg in both female and male rats independent of hydration status. U50488 diuretic effects were inhibited by norBNI pre-administration. Water-loading reduced data variability for urine volume in males, but not in females, compared with normally hydrated rats. Sex differences were also evident in U50488 eliciting a significant increase in sodium and potassium ion excretion only in males. This may suggest different mechanisms of U50488 diuretic action in males where renal excretion mechanisms are directly affected more than in females.

Sports drinks do not increase acute kidney injury risk in males during industrial work in the heat when euhydration is maintained, a randomized crossover trial.

Industrial workers regularly perform physical labor under high heat stress, which may place them at risk for dehydration and acute kidney injury. Current guidelines recommend that workers should consume sports drinks to maintain euhydration during work shifts. However, the impact of fructose sweetened sports drinks on acute kidney injury risk is unknown. The purpose of this study was to investigate the effects of sports drink consumption on markers of acute kidney injury following simulated industrial work in the heat. Twenty males completed two matched 2 h simulated industrial work trial visits in a warm and humid environment (30 °C and 55% relative humidity). During and following the bout of simulated work, participants consumed either a commercially available sports drink or a noncaloric placebo. Urine and blood samples, collected pre-, post-, and 16 h post-work were assayed for markers of hydration (plasma/urine osmolality, and urine specific gravity) and acute kidney injury (KIM-1 and NGAL). There were no differences in physiological or perceptual responses to the bout of work (interaction p > 0.05 for all indices), and markers of hydration were similar between trials (interaction p > 0.05 for all indices). KIM-1 (Placebo: Δ Ln 1.18 ± 1.64; Sports drink: Δ Ln 1.49 ± 1.10 pg/mL; groupwide d = 0.89, p < 0.001) and NGAL (Placebo: Δ Ln 0.44 ± 1.11; Sports drink: Δ Ln 0.67 ± 1.22 pg/mL; groupwide d = 0.39, p = 0.03) were elevated pre- to post-work, but there were no differences between trials (interaction p > 0.05). These data provide no evidence that consumption of fructose sweetened sports drinks increases the risk of acute kidney injury during physical work in the heat.

H2OAthletes study protocol: effects of hydration changes on neuromuscular function in athletes.

We aim to understand the effects of hydration changes on athletes' neuromuscular performance, on body water compartments, fat-free mass hydration and hydration biomarkers and to test the effects of the intervention on the response of acute dehydration in the hydration indexes. The H2OAthletes study (clinicaltrials.gov ID: NCT05380089) is a randomised controlled trial in thirty-eight national/international athletes of both sexes with low total water intake (WI) (i.e. < 35·0 ml/kg/d). In the intervention, participants will be randomly assigned to the control (CG, n 19) or experimental group (EG, n 19). During the 4-day intervention, WI will be maintained in the CG and increased in the EG (i.e. > 45·0 ml/kg/d). Exercise-induced dehydration protocols with thermal stress will be performed before and after the intervention. Neuromuscular performance (knee extension/flexion with electromyography and handgrip), hydration indexes (serum, urine and saliva osmolality), body water compartments and water flux (dilution techniques, body composition (four-compartment model) and biochemical parameters (vasopressin and Na) will be evaluated. This trial will provide novel evidence about the effects of hydration changes on neuromuscular function and hydration status in athletes with low WI, providing useful information for athletes and sports-related professionals aiming to improve athletic performance.

Short-term association between outdoor temperature and the hydration-marker copeptin: a pooled analysis in five cohorts.

BACKGROUND: Whereas outdoor temperature is linked to both mortality and hydration status, the hormone vasopressin, measured through the surrogate copeptin, is a marker of cardiometabolic risk and hydration. We recently showed that copeptin has a seasonal pattern with higher plasma concentration in winter. Here, we aimed to investigate the association between outdoor temperature and copeptin. METHODS: Copeptin was analysed in fasting plasma from five cohorts in Malmö, Sweden (n = 26,753, 49.7% men, age 18-86 years). We utilized a multivariable adjusted non-linear spline model with four knots to investigate the association between short-term temperature (24 h mean apparent) and log copeptin z-score. FINDINGS: We found a distinct non-linear association between temperature and log copeptin z-score, with both moderately low and high temperatures linked to higher copeptin concentration (p < 0.0001). Between 0 °C and nadir at the 75th temperature percentile (corresponding to 14.3 °C), log copeptin decreased 0.13 z-scores (95% CI 0.096; 0.16), which also inversely corresponded to the increase in z-score log copeptin between the nadir and 21.3 °C. INTERPRETATION: The J-shaped association between short-term temperature and copeptin resembles the J-shaped association between temperature and mortality. Whereas the untangling of temperature from other seasonal effects on hydration warrants further study, moderately increased water intake constitutes a feasible intervention to lower vasopressin and might mitigate adverse health effects of both moderately cold and hot outdoor temperatures. FUNDING: Swedish Research Council, Å Wiberg, M Stephen, A Påhlsson, Crafoord and Swedish Heart-Lung Foundations, Swedish Society for Medical Research and Swedish Society of Medicine.

La sed ¿un mecanismo suficiente para lograr euhidratación?: una revisión narrativa / Is thirst sufficient as a mechanism for achieving euhydration? a narrative review

Capitán, C. y Aragón, L.F. (2023). La sed ¿un mecanismo suficiente para lograr euhidratación?: una revisión narrativa. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 21(1), 1-16. El papel de la percepción de sed para mantener el balance hídrico ha sido ampliamente estudiado, tanto durante el ejercicio como después de este. Sin embargo, la forma de evaluarla y la eficacia de los instrumentos existentes son aún áreas que necesitan más investigación. El objetivo de esta revisión fue integrar, de forma general, la información disponible en la literatura sobre el funcionamiento del mecanismo de la sed como respuesta a la deshidratación durante y después del ejercicio. Se explican los mecanismos fisiológicos y las respuestas de estos durante y posterior al ejercicio; además, se describen los instrumentos disponibles en la literatura científica, sus debilidades y fortalezas, y se plantea una serie de preguntas que aún no tienen respuesta en el área. En esta revisión se presenta el aspecto teórico de los mecanismos de la sed, además, se discuten los estudios científicos que respaldan o refutan el comportamiento de estos mecanismos en el ejercicio. Finalmente, se hace un resumen de las principales conclusiones extraídas de la literatura científica sobre la sed como un mecanismo suficiente para prevenir la deshidratación tanto durante como después del ejercicio.

Capitán, C. y Aragón, L.F. (2023). Is thirst sufficient as a mechanism for achieving euhydration? a narrative review. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 21(1), 1-16. The role of thirst perception for keeping hydric balance, both during and after exercise, has been extensively studied. However, the way to assess it and the effectiveness of the existing instruments are areas that still require further research. The objective of this review is to integrate, in a general way, the information available in the literature on the functioning of the thirst mechanism as a response to dehydration during and after exercise. The physiological mechanisms and their responses during and after exercise are explained. In addition, a description of the instruments available in scientific literature is included, together with their weaknesses and strengths, and a series of as yet unanswered questions in this area are raised. This review presents the theoretical aspect of thirst mechanisms, and discusses the scientific studies that support or refute the behavior of these mechanisms in exercise. Finally, a summary is made of the major conclusions drawn from the scientific literature on thirst as a sufficient mechanism to prevent dehydration both during and after exercise.

Capitán, C. y Aragón, L.F. (2023). A sede é um mecanismo suficiente para alcançar a hidratação? uma revisão narrativa. PENSAR EN MOVIMIENTO: Revista de Ciencias del Ejercicio y la Salud, 21(1), 1-16. O papel da percepção da sede na manutenção do equilíbrio hídrico tem sido amplamente estudado, tanto durante quanto após o exercício. Entretanto, como avaliá-la e a eficácia dos instrumentos existentes ainda são áreas que necessitam de mais pesquisas. Esta revisão visou integrar, de forma geral, as informações disponíveis na literatura sobre o funcionamento do mecanismo da sede em resposta à desidratação durante e após o exercício. Ele explica os mecanismos fisiológicos e suas respostas durante e após o exercício, descreve os instrumentos disponíveis na literatura científica, seus pontos fracos e fortes, e levanta uma série de questões que permanecem sem resposta no campo. Esta revisão apresenta o aspecto teórico dos mecanismos da sede e discute os estudos científicos que respaldam ou refutam o comportamento desses mecanismos no exercício. Finalmente, é feito um resumo das principais conclusões extraídas da literatura científica sobre a sede como mecanismo suficiente para prevenir a desidratação tanto durante quanto após o exercício.

Hidratación combinada y efectos en la salud vocal en estudiantes de logopedia / Combined hydration and effects on the vocal health in speech language pathology students

Objetivo: Evaluar si la hidratación combinada (sistémico y superficial) disminuye síntomas vocales y mejora la eficiencia glótica en una muestra de estudiantes de Logopedia. Material y Métodos: Estudio cuasi-experimental con grupo Hidratación (N=20) y grupo Control (N=19) con valoración pre y post-hidratación (ingesta de agua 1.500 ml/día e inhalaciones dos veces/día durante una semana). Se analizaron factores deshidratantes relacionados con la voz (uso vocal, tabaco, alcohol, café, respiración bucal), síntomas vocales y eficiencia glótica a través del Tiempo Máximo Fonación, Fo, Jitter % y Shimmer %, usando Multi-Dimensional Voice Program (MDVP). Resultados: Grupo Hidratación disminuyó significativamente sequedad (p = 0,013), carraspeo (p = 0,005), fatiga vocal (p = 0,015), dolor faríngeo (p = 0,009), Shimmer % (p = 0,048) frente al grupo Control que sólo disminuyó el carraspeo (p = 0,02). Conclusiones: La hidratación combinada puede ser una medida útil para mejorar la salud vocal de los futuros logopedas. (AU

Objective: To evaluate if a combined hydration (systemic and superficial) decreases the vocal symptoms and improves the glottic efficiency in a sample of university students of Speech therapist. Material and Methods: Quasi-experimental study with Hydration group (N=20) and Control group (N=19) with pre and post-hydration assessment (water intake 1.500 ml/day and steam twice/day for a week). Voice-related dehydrating factors (vocal use, tobacco, alcohol, coffee, oral breathing), vocal symptoms and glottic efficiency through Maximum Phonation Time, Fo, Jitter % and Shimmer %, using Multi-Dimensional Voice Program (MDVP) were analyzed. Results: Hydration group significantly decreased dryness (p = .013=, throat clearing (p = .005), vocal fatigue (p = .015), pain throat (p = .009) and Shimmer % (p = .048) compared to the Control group, which only decreased throat clearing (p = .02). Discussion: The combined hydration may be a useful measure to improve vocal health for future speech-language-pathologists. (AU)

Transepidermal water loss and stratum corneum hydration in forearm versus hand palm.

BACKGROUND: Skin measurements of transepidermal water loss (TEWL) and stratum corneum hydration (SCH) reflect different aspects of skin physiology. Since epidermal water loss depends on epidermal-to-air water vapor gradients, a possible quantitative relationship between TEWL and SCH may exist. This investigation's purpose was to test the possible TEWL-SCH relationship. MATERIALS AND METHODS: SCH and TEWL were measured noninvasively on forearm and palmer thenar eminence (hand) in 40 young adults (20 males) along with total body fat percentage (FAT) via bioimpedance. RESULTS: A significant positive nonlinear correlation (p < 0.001) was detected between SCH and TEWL in hands of the male cohort that occurred when SCH exceeded a threshold level. This threshold level was not exceeded in male or female forearms and forearms did not display a SCH-TEWL correlation. There was a weak inverse dependence of TEWL on FAT on both forearm and hand (p < 0.05), but no SCH-FAT relationship was observed. TEWL values on the forearm and hand were moderately correlated with each other (p = 0.002) but SCH values were not. CONCLUSION: The findings clarify the relationship between forearm and palmer hydration and TEWL values, and their relationship to total body fat percentages in young healthy adults. The significant correlation between palmer stratum corneum hydration and palmer TEWL that was discovered in the male but not the female cohort suggests a threshold hydration level for which TEWL depends both on skin barrier function and stratum corneum hydration. This implies that conditions with increased SCH may in part account for elevated TEWL values.

Impacto de una intervención educativa nutricional para pacientes en hemodiálisis medido mediante la escala Malnutrición Inflamación y la bioimpedancia eléctrica / Impact of a nutritional education intervention for hemodialysis patients measured with the Malnutrition Inflammation Score and electrical bioimpedance

Introducción: Los pacientes en hemodiálisis pueden presentar alteraciones en su composición corporal, para ello las unidades de nefrología cuentan con herramientas, como son la bioimpedancia y la escala “Malnutrition Inflamation Score” para prevenir, detectar y diagnosticar estados de desnutrición.Objetivos: Evaluar el impacto de una intervención educativa sobre el estado nutricional de los pacientes en hemodiálisis, medido mediante la escala Malnutrición Inflamación y la bioimpedancia.Material y Método: Estudio cuasiexperimental realizado en 48 pacientes sometidos a hemodiálisis. Se analizaron variables sociodemográficas y clínicas, de composición corporal de los pacientes en dos mediciones, mediante bioimpedancia y escala de malnutrición MIS.Los pacientes que presentaron una puntuación de la escala MIS≥6 recibieron una intervención nutricional, evaluándolos nuevamente a los 6 meses.Resultados: La media de edad fue de 69,9±13,6 años, 29 (60,41%) eran hombres. Los pacientes llevaban en tratamiento con hemodiálisis una mediana de tiempo de 24(P25:10,3-P75:59,3) meses.Los pacientes que presentaron valores de la escala MIS≥6 fueron 24(50%), recibiendo la intervención educativa.En los pacientes que no recibieron la intervención el resultado MIS empeoró a los 6 meses (3,4 vs 5,4, p=0,002).Conclusiones: Aquellas personas que no recibieron una intervención educativa empeoraron sus resultados nutricionales frente a quienes si la recibieron. Cabe destacar la importancia de utilizar de forma sistematizada instrumentos validados, como la bioimpedancia y la escala MIS, para hacer un seguimiento del estado nutricional de los pacientes en hemodiálisis. (AU)

Introduction:Hemodialysis patients may present alterations in body composition. Nephrology units have tools such as bioimpedance and the Malnutrition Inflammation Score (MIS) to prevent, detect and diagnose malnutrition.Objective:To assess the impact of an educational interven-tion on the nutritional status of hemodialysis patients using the MIS and bioimpedance.Material and Method:Quasi-experimental study carried out in 48 hemodialysis patients. Sociodemographic and clinical variables as well as patient body composition were analysed in two measurements using bioimpedance and MIS. Patients with an MIS≥6 received a nutritional intervention, with a re-assessment at 6 months.Results: Mean age was 69.9±13.6 years; 29 (60.41%) were male. Patients had been on hemodialysis for a median of 24 (P25:10.3-P75:59.3) months. Patients with MIS values≥6 were 24 (50%), receiving such an educational intervention. In patients who did not receive the intervention the MIS value worsened at 6 months (3.4 vs. 5.4, p=0.002).Conclusions: People who did not receive an educational intervention worsened their nutritional outcomes compared to those who did. The importance of systematically using validated instruments such as bioimpedance and the MIS to monitor the nutritional status of hemodialysis patients should be emphasised. (AU)

Hydration status according to impedance vectors and its association with clinical and biochemical outcomes and mortality in patients with chronic kidney disease / Estado de hidratación por vectores de impedancia y su asociación con desenlaces clínicos, bioquímicos y mortalidad en pacientes con enfermedad renal crónica

Background: the evaluation of hydration status and body composition in patients with kidney disease is vital for proper management, since overhydration is associated with cardiovascular complications. Patients with chronic kidney disease (CKD) begin to show perceptible alterations in hydration during the intermediate stages of the disease; however, there is little information regarding the evaluation of blood volume status through bioelectrical impedance vector analysis (BIVA) in this population. Objective: to determine the association between hydration status measured with BIVA and biochemical and clinical parameters and mortality in patients with stage G3a, G3b and G4 CKD. Material and methods: a cross-sectional study was conducted with patients with stage G3a, G3b and G4 CKD who underwent bioelectrical impedance analysis (BIA). The following biochemical and clinical parameters were determined: serum and urinary albumin, hematocrit, serum electrolytes and creatinine, estimated glomerular filtration rate (eGFR, using the CKD-EPI formula), 24-hour urine output and blood pressure. The clinical and biochemical variables were associated with the components of the BIA. According to the resistance/height (R/H) and reactance/height (Xc/H) values, the BIVA results were individually plotted on reference ellipses to identify patients with abnormal hydration states. The patients were classified by group according to hydration status and CKD stage z-scores, and differences in clinical, biochemical and BIA parameters were identified. Mortality was determined by hydration status. (AU)

Antecedentes: la evaluación del estado de hidratación y la composición corporal es imprescindible para los pacientes con enfermedad renal crónica (ERC) en estadios intermedios, ya que en esta etapa inician con alteraciones hídricas perceptibles; sin embargo, existe poca información en dicha población sobre la evaluación del estado de volemia mediante el análisis de vectores de bioimpedancia eléctrica (BIVA). Objetivo: asociar el estado de hidratación medido por BIVA con parámetros bioquímicos, clínicos y mortalidad en pacientes con ERC G3a G3b y G4 Material y métodos: estudio transversal en el cual se incluyó a pacientes con ERC en estadios G3a G3b y G4 a los que se les realizó un análisis de impedancia bioeléctrica (IBE) y en los que se determinaron parámetros bioquímicos y clínicos: albúmina sérica y urinaria, hematocrito, electrólitos y creatinina séricos, tasa de filtrado glomerular estimada (TFGe) (fórmula CKD-EPI), diuresis de 24 horas y presión arterial. Las variables clínicas y bioquímicas se asociaron con los componentes de la IBE. Los valores de resistencia/estatura (R/H) y reactancia/estatura (Xc/H) se graficaron individualmente sobre las elipses de referencia para identificar a pacientes con estados de hidratación anormales. Se ubicaron grupos según el estado de hidratación y estadio de ERC en z-score y se identificaron las diferencias de parámetros clínicos, bioquímicos y de IBE. Se determinó la mortalidad según el estado de hidratación. (AU)

Dopamine subsystems that track internal states.

Food and water are rewarding in part because they satisfy our internal needs1,2. Dopaminergic neurons in the ventral tegmental area (VTA) are activated by gustatory rewards3-5, but how animals learn to associate these oral cues with the delayed physiological effects of ingestion is unknown. Here we show that individual dopaminergic neurons in the VTA respond to detection of nutrients or water at specific stages of ingestion. A major subset of dopaminergic neurons tracks changes in systemic hydration that occur tens of minutes after thirsty mice drink water, whereas different dopaminergic neurons respond to nutrients in the gastrointestinal tract. We show that information about fluid balance is transmitted to the VTA by a hypothalamic pathway and then re-routed to downstream circuits that track the oral, gastrointestinal and post-absorptive stages of ingestion. To investigate the function of these signals, we used a paradigm in which a fluid's oral and post-absorptive effects can be independently manipulated and temporally separated. We show that mice rapidly learn to prefer one fluid over another based solely on its rehydrating ability and that this post-ingestive learning is prevented if dopaminergic neurons in the VTA are selectively silenced after consumption. These findings reveal that the midbrain dopamine system contains subsystems that track different modalities and stages of ingestion, on timescales from seconds to tens of minutes, and that this information is used to drive learning about the consequences of ingestion.

Solución de St Marks como alternativa al manejo de la hiponatremia en la fístula ileal / St Marks solution as an alternative to the management of hyponatremia in ileal fistula

Las fístulas, especialmente las de alto débito, frecuentemente precisan hidratación y reposición electrolítica agresiva, destacando las pérdidas de sodio como principal complicación hidroelectrolítica.Varón de 53 años intervenido en julio de 2017 y que en noviembre 2018 ingresó para reconstrucción del tránsito intestinal. Tras varias intervenciones quirúrgicas apareció una fístula pioestercoracea de alto débito a nivel de íleo. El manejo de la fístula fue conservador con nutrición parenteral total individualizada lográndose balance hidroelectrolítico óptimo. Posteriormente el paciente perdió tanto el acceso venoso central como los periféricos, siendo imposible la canalización de una vía periférica en varios días. Durante este periodo el paciente desarrolló una hiponatremia severa que desde el servicio de Farmacia fue abordada por la vía oral con una solución de hidratación específica, como la solución de St Marks, que se caracteriza por su alto contenido en sodio y bajo en potasio para evitar hiperpotasemias que pueden dar lugar en estos pacientes. Con el tratamiento instaurado se logró recuperar las cifras de natremia evitando complicaciones neurológicas hasta que finalmente se canalizó una vía periférica. En nuestro paciente esta solución resultó ser efectiva logrando remontar drásticamente las cifras de natremia cercana a valores normales. Así pues, la solución de St Marks puede ser una alternativa a la vía intravenosa cuando no esté disponible o ser incluso complementaria a ésta. (AU)

Fistulas, especially those with high output, frequently require hydration and aggressive electrolyte replacement, highlighting sodium losses as the main hydroelectrolytic complication.53-year-old man who underwent surgery in July 2017 and who was admitted in November 2018 for intestinal transit reconstruction. After several surgical interventions, a high-output piostercoraceous fistula appeared at the ileus level. Management of the fistula was conservative with individualized total parenteral nutrition, achieving optimal fluid and electrolyte balance. Subsequently, the patient lost both the central and peripheral venous access, being several days without vascular access. During this period, the patient developed severe hyponatremia that the Pharmacy service treated orally with a specific hydration solution, St Marks’s solution, which is characterized by its high sodium and low potassium content to avoid hyperkalemias that can give rise in these patients. With the established treatment, it was possible to recover the levels of natraemia avoiding neurological complications until finally peripheral venous catheterization was placed. In our patient, this solution turned out to be effective, managing to drastically raise the levels of natraemia close to normal values. Thus, the St Marks solution can be an alternative to the intravenous access when it is not available or even be complementary to it. (AU)

Production of reactive oxygen species and involvement of bioprotectants during anhydrobiosis in the tardigrade Paramacrobiotus spatialis.

Water unavailability is an abiotic stress causing unfavourable conditions for life. Nevertheless, some animals evolved anhydrobiosis, a strategy allowing for the reversible organism dehydration and suspension of metabolism as a direct response to habitat desiccation. Anhydrobiotic animals undergo biochemical changes synthesizing bioprotectants to help combat desiccation stresses. One stress is the generation of reactive oxygen species (ROS). In this study, the eutardigrade Paramacrobiotus spatialis was used to investigate the occurrence of ROS associated with the desiccation process. We observed that the production of ROS significantly increases as a function of time spent in anhydrobiosis and represents a direct demonstration of oxidative stress in tardigrades. The degree of involvement of bioprotectants, including those combating ROS, in the P. spatialis was evaluated by perturbing their gene functions using RNA interference and assessing the successful recovery of animals after desiccation/rehydration. Targeting the glutathione peroxidase gene compromised survival during drying and rehydration, providing evidence for the role of the gene in desiccation tolerance. Targeting genes encoding glutathione reductase and catalase indicated that these molecules play roles during rehydration. Our study also confirms the involvement of aquaporins 3 and 10 during rehydration. Therefore, desiccation tolerance depends on the synergistic action of many different molecules working together.

Empleo de la vía subcutánea en un hospital de segundo nivel. Revisión del uso actual y nuevas propuestas / Use of the subcutaneous route in a second level hospital. A review of current use and new proposals

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