Fluid and electrolyte physiology

This review summarises some of my work on fluid and electrolyte balance over the past 25 years and shows how the studies have influenced clinical practice. Missing pieces in the jigsaw are filled in by summarising the work of others. The main theme is the biochemical, physiological and clinical problems caused by inappropriate use of saline solutions including the hyperchloraemic acidosis caused by 0.9% saline. The importance of accurate and near-zero fluid balance in clinical practice is also emphasised. Perioperative fluid and electrolyte therapy has important effects on clinical outcome in a U-shaped dose response fashion, in which excess or deficit progressively increases complications and worsens outcome...

In the kidney, the flow rate of the pro-urine through the renal tubules is highly variable. The tubular epithelial cells sense these variations in pro-urinary flow rate in order to regulate various physiological processes, including electrolyte reabsorption. One of the mechanosensitive pathways activated by flow is the release of ATP, which can then act as a autocrine or paracrine factor. Increased ATP release is observed in various kidney diseases, among others autosomal dominant polycystic kidney disease (ADPKD)...

Congenital anorectal malformation (ARM) is a diverse group of anomalies affecting the development of the anal and rectal regions, with an estimated incidence of one in every 5000 live births. The colostomy is commonly performed as part of the staged management of children with ARM to prevent complications. However, the presence of acute watery diarrhea in children with ARM and colostomy poses significant management challenges due to the altered anatomy and physiology affecting stool regulation and absorption, exacerbated by various factors including infections, dietary issues, medication side effects, and underlying gastrointestinal complications...

The choroid plexus is a small monolayered epithelium located in the brain ventricles and serves to secrete the cerebrospinal fluid (CSF) that envelops the brain and fills the central ventricles. The CSF secretion is sustained with a concerted effort of a range of membrane transporters located in a polarized fashion in this tissue. Prominent amongst these are the Na+ /K+ -ATPase, the Na+ ,K+ ,2Cl- cotransporter (NKCC1), and several HCO3 - transporters, which together support the net transepithelial transport of the major electrolytes, Na+ and Cl- , and thus drive the CSF secretion...

BACKGROUND: Precise fluid balance monitoring is essential for patient treatment, as incorrect fluid balance can lead to disorders. OBJECTIVE: This study aimed to assess the accuracy of the digital technology LICENSE (LIquid balanCE moNitoring SystEm) for fluid balance charting and compare it to the standard method (SM) to determine its usability in clinical practice. METHODS: This prospective study included 20 patients. The results from LICENSE were compared to those from SM and a reference measurement (manual weight of fluids, RM)...

BACKGROUND: Ostomy/Stoma is a common entity in patients operated for small bowel perforation in developing countries. Delay in presentation, poor general condition, malnutrition and lack of health infrastructure in peripheral areas are some of the causes leading to severe sepsis at presentation. Exteriorising the perforation site as stoma/ostomy is the preferred salvage procedure. Proximal stoma/ostomy is high output and cause fluid and electrolyte imbalance. Also it is difficult to maintain nutrition with oral feeds, as partially digested food along with digestive enzymes gets lost through the stoma...

Aldosterone was initially identified as a hormone primarily related to regulation of fluid and electrolyte homeostasis. However, over the past twenty years there has been an increasing appreciation of its role in regulation of vascular function and pathophysiology in the setting of hypertension, atherosclerosis, and heart failure. The purpose of this review is to highlight recent advances in our understanding the biology of aldosterone as it relates to the pathophysiology and the management of vascular disease-especially related to hypertension...

PURPOSE: To determine whether carbohydrate ingestion would reduce cognitive dysfunction in humans following long duration passive heat stress (PHS) versus consuming electrolytes alone. METHODS: Fifteen young (27 ± 4 y) healthy adults were exposed to 120 min of PHS through the use of a liquid perfused suit (50 °C) on two randomized visits. Subjects consumed fluids supplemented with electrolytes (E) or electrolytes + carbohydrates (E + C)...

BACKGROUND: Use of dextrose-containing maintenance fluids prior to parenteral nutrition initiation is speculated to reduce the risk for refeeding syndrome. We aimed to assess if the use of dextrose vs. non-dextrose maintenance fluids before parenteral nutrition initiation changes electrolyte supplementation requirements and shifts during initiation. METHODS: This retrospective cohort study included nothing by mouth patients who received maintenance fluids ≥ 72 hours before parenteral nutrition...

Approximately 30% of all children and neonates admitted to the intensive care unit (ICU) experience acute kidney injury (AKI). Children with AKI are largely poorly fed and experience high rates of malnutrition. Nutrition prescription and provision are exceptionally challenging for critically ill neonates, infants, and children with AKI given the dynamic nature of AKI and its respective treatment modalities. Managing the nutrition prescription of critically ill neonates, infants, and children with AKI requires nutrition support clinicians to have a high-level understanding of the various treatment modalities for AKI, which can affect the patient's protein, fluid, electrolyte, and mineral needs...

OBJECTIVES: Concise definitive review of the physiology of IV fluid (IVF) use in critically ill patients. DATA SOURCES: Available literature on PubMed and MEDLINE databases. STUDY SELECTION: Basic physiology studies, observational studies, clinical trials, and reviews addressing the physiology of IVF and their use in the critically ill were included. DATA EXTRACTION: None. DATA SYNTHESIS: We combine clinical and physiologic studies to form a framework for understanding rational and science-based use of fluids and electrolytes...

Refeeding syndrome (RS) is characterized by electrolyte imbalances that can occur in malnourished and abruptly refed patients. Typical features of RS are hypophosphatemia, hypokalemia, hypomagnesemia, and thiamine deficiency. It is a potentially life-threatening condition that can affect both adults and children, although there is scarce evidence in the pediatric literature. The sudden increase in food intake causes a shift in the body's metabolism and electrolyte balance, leading to symptoms such as weakness, seizures, and even heart failure...

Mammalian kidneys are specialized to maintain fluid and electrolyte homeostasis. The epithelial transport processes along the renal tubule that match output to input have long been the subject of experimental and theoretical study. However, emerging data have identified a new dimension of investigation: sex. Like most tissues, the structure and function of the kidney is regulated by sex hormones and chromosomes. Available data demonstrate sex differences in the abundance of kidney solute and electrolyte transporters, establishing that renal tubular organization and operation are distinctly different in females and males...

BACKGROUND: Recently approved treatments for spinal muscular atrophy (SMA) may shift clinical care priorities to secondary complications associated with SMA-related aging. To date, there is little knowledge about the natural history of morbidities across the adult lifespan for SMA. The objective of this study was to identify the prevalence and odds ratio (OR) of various morbidities among adults with vs. without SMA prior to SMA-related treatment. METHODS: This was a retrospective cohort study that accessed Medicare fee-for-service and commercial claims data from 01/01/2008-12/22/2016...

BACKGROUND: Existing nonhuman primate models of Ebola virus infection have not fully characterized the physiology of shock and its association with daily virological, clinical, and immunological parameters. We implemented a nonhuman primate critical care model to study the progression and nature of shock following Ebola virus infection relative to viremia, organ dysfunction, coagulopathy, and daily high-dimensional circulating immune cell phenotyping. METHODS: Two rhesus macaques were inoculated intramuscularly with a target dose of 1000 plaque forming units of Ebola virus, Makona variant...

Calcium (Ca2+ ) transport along the nephron occurs via specific transcellular and paracellular pathways, and is coupled to the transport of other electrolytes. Notably sodium (Na+ ) transport establishes an electrochemical gradient to drive Ca2+ reabsorption. Hence, alterations in renal Na+ handling, under pathophysiological conditions or pharmacological manipulations, can have major effects on Ca2+ transport. An important class of pharmacological agent is diuretics, which are commonly prescribed for the management of blood pressure and fluid balance...

PURPOSE: Maintaining an appropriate hydration level by ingesting fluid in a hot environment is a measure to prevent heat-related illness. Caffeine-containing beverages, including green tea (GT), have been avoided as inappropriate rehydration beverages to prevent heat-related illness because caffeine has been assumed to exert diuretic/natriuretic action. However, the influence of caffeine intake on urine output in dehydrated individuals is not well documented. The aim of the present study was to examine the effect of fluid replacement with GT on body fluid balance and renal water and electrolyte handling in mildly dehydrated individuals...

BACKGROUND: Heat induces a thermoregulatory strain that impairs cardiopulmonary exercise capacity. The aim of the current study is to elucidate the effect of isolated dehydration on cardiopulmonary exercise capacity in a model of preparticipating hypohydration. METHODS: Healthy recreational athletes underwent a standardised fluid deprivation test. Hypohydration was assessed by bioelectrical impedance analysis (BIA) and laboratory testing of electrolytes and retention parameters in the blood and urine...

In recent years, there has been a rapid increase in demand for wearable sensors, particularly these tracking the surroundings, fitness, and health of people. Thus, selective detection in human body fluid is a demand for a smart lifestyle by quick monitoring of electrolytes, drugs, toxins, metabolites and biomolecules, proteins, and the immune system. In this review, these parameters along with the main features of the latest and mostly cited research work on nanostructured wearable electrochemical and biosensors are surveyed...

Malnutrition is one of the most frequent effects of an enterocutaneous fistula (ECF). There are some factors that contribute to it including inadequate intake, fluid loss via fistula and underlying disease. The role of nutrition is very important as a part of ECF therapy to give adequate nutrition, maintain fluid and electrolyte state and increase the likelihood of fistula closure spontaneously. Therefore, it is anticipated that adequate nutrition management will lower morbidity and mortality while enhancing clinical results...