Extracellular Fluid Balance Research Articles

Endothelial Damage and Muscle Wasting in Cardiac Surgery Patients.

This is a post-hoc analysis to assess the effect of anesthesia, surgical trauma, and extracorporeal circuit on endothelial integrity, microvascular permeability, and extracellular fluid balance, as well as on skeletal muscle catabolism, in patients undergoing elective cardiac surgery. We included 127 well-nourished patients undergoing "on-pump" elective cardiac surgery. One day prior to surgery (D0) and again on postoperative day 7 (POD7), body mass index, body composition assessment, hand-grip strength (HGS), and mid-upper arm muscle circumference (MAMC) were measured. Patients were assigned to early recovery (ER) and late recovery (LR) groups, depending on the duration of ICU stay (cut-off 48 hours). The magnitude of change (Δ) in all parameters studied was assessed in ER versus LR groups, regarding(i) epithelial tissue dysfunction (Δ-Extra-Cellular Water percentage (Δ-ECW%), Δ-Phase Angle (Δ-PhA)), (ii) skeletal muscle mass catabolism (Δ-Skeletal muscle mass reduction%, Δ-Hand Grip Strength (Δ-HGS) and Δ-Mid Upper-Arm Muscle Circumference (Δ-MAMC)). Baseline measurements were similar in both groups. A significant difference was observed in all Δ-parameters studied (Δ-ECW%, Δ-PhA and muscle catabolism, Δ-HGS, Δ-MAMC), the worse results being correlated to the LR group. The results raise the issue that patients with early recovery may silently have pathological conditions, continuing even on the day of discharge- further research should be planned.

Influence of experimental metabolic syndrome on bioimpedance spectroscopy indicators of rat body

The objective of this experiment was to establish sex-related differences in the parameters of bioimpedance spectroscopy of the Wistar rat’s bodies in the experimental metabolic syndrome (endocrine-salt model).
 Sexual dependencies of bioimpedance measurements in intact animals have been determined for the first time: males have higher amount of total fluid, but lower one of total fat. The intra/extracellular fluid balance in males is characterized with ratio 2:1, while in females is the other one - 1:1.
 For the first time the formation of the metabolic syndrome has already been determined on the seventh day in females which lead to decreasing in the percentage of total fat and to changing of the intra / extracellular fluid balance to ‘male’ type - 2:1. The last one should be considered as a sign of intracellular hyperhydration. In males the examined parameters have been being within the control values ​​throughout 21 days of experiment.

A model of end-expiratory lung impedance dependency on total extracellular body water

Electrical impedance tomography (EIT) is an attractive method for clinical monitoring of patients during mechanical ventilation. This study evaluates lung impedance measurements using Dräger PulmoVista 500 EIT system on an animal model. Mechanically ventilated model was created. Vital signs were monitored as well as mechanical ventilation parameters. Extracellular fluid balance and blood volume were handled as follows: 30–40% of total blood volume were removed and returned back, 0.5 to 1 litre of Ringer's solution was injected afterwards. The quantity of injected fluids was recorded for each animal. During this process thoracic electrical impedance measurement was performed. Recorded data from PulmoVista 500 EIT system were analysed using the official Dräger EIT Data Analysis Tool. The dependency of end-expiratory lung impedance on the change of fluid balance was observed. The relation between end-expiratory (minimum impedance value) frames and changes of fluid balance is shown. Preliminary results strongly support the expectation that electrical impedance of thorax can be affected by total extracellular fluid change.

Involvement of glomerular renin-angiotensin system (RAS) activation in the development and progression of glomerular injury.

Recently, there has been a paradigm shift away from an emphasis on the role of the endocrine (circulating) renin−angiotensin system (RAS) in the regulation of the sodium and extracellular fluid balance, blood pressure, and the pathophysiology of hypertensive organ damage toward a focus on the role of tissue RAS found in many organs, including kidney. A tissue RAS implies that RAS components necessary for the production of angiotensin II (Ang II) reside within the tissue and its production is regulated within the tissue, independent of the circulating RAS. Locally produced Ang II plays a role in many physiological and pathophysiological processes such as hypertension, inflammation, oxidative stress, and tissue fibrosis. Both glomerular and tubular compartments of the kidney have the characteristics of a tissue RAS. The purpose of this article is to review the recent advances in tissue RAS research with a particular focus on the role of the glomerular RAS in the progression of renal disease.

Plasma and urine nitric oxide levels in healthy Turkish children

Nitric oxide (NO) is an important messenger molecule with a wide range of actions in virtually all cell systems and organs. In kidneys it participates in glomerular and medullary hemodynamics, tubuloglomerular feed-back, renin secretion, and extracellular fluid balance. Although the role of NO in regulating renal function in adults is well-established, it has recently been suggested that NO has a more critical role in maintaining basal renal blood flow and glomerular filtration rate (GFR) in the developing kidney. NO is rapidly metabolized to the stable end products nitrite and nitrate, which are more slowly excreted into the urine. Thus these metabolites can be recommended as useful markers of endogenous NO synthase activity, despite limited data about age-related changes in in-vivo NO production. The aims of this study were to determine age-related normal reference values of serum and urinary NO metabolites and to assess the probable relationship between these metabolites and the GFR. Normal levels of NO end products in blood and urine of 296 healthy children (117 female, 179 male) between the ages of 0 and 16 were investigated, as was whether these values change with age. Serum and urinary nitrate levels did not differ according to sex. Serum nitrate levels are higher in younger children, especially in the newborn period, and decrease with age. Nitrate levels in urine are higher in younger children with a peak in infancy (1 month to 1 year) and decrease with age. It was demonstrated that this decrease in serum and urinary nitrate levels with age parallels the increase in GFR. In conclusion, urinary NO products may be an indirect marker of serum NO levels and NO might have an important regulatory function both in the maintenance of renal function and in the maturation of the developing kidneys.

Noradrenaline up‐regulates the neuronal and the inducible nitric oxide synthase isoforms in magnocellular neurons of rat brain slices

Nitric oxide (NO) and noradrenaline (NA) are suggested to be implicated in the regulation of neuropeptide secretion in the supraoptic nuclei (SON) and the paraventricular nuclei (PVN) of the hypothalamus. Our study demonstrates short-term interactions between NA and the activity and expression of NO synthase (NOS) in magnocellular neurons, by using an ex vivo model of hypothalamic slices. In the SON as well as in the PVN, total NOS activity exhibited a time-dependant increase after an incubation with NA. In the SON, this increase of total NOS activity was in part the consequence of stimulation of the iNOS activity. Coimmunodetections showed that cells expressing the inducible form of NOS were not astrocytes but magnocellular neurons. Steady-state levels of iNOS and nNOS mRNA were dramatically enhanced by NA, particularly in the SON. Consequently, we provide new evidence that iNOS could play an important role in multiple physiological functions, including extracellular fluid balance, lactation, and parturition.

Ontogeny of renal sodium transport

One of the main functions of the adult kidney is to maintain a constant extracellular fluid balance. The adult kidney does this, by and large, by filtering a massive quantity of fluid and reabsorbing the solutes needed to maintain volume and electrolyte homeostasis, while leaving the waste products to be excreted in the urine. One of the most precisely regulated functions of the adult kidney is to maintain sodium balance. The challenge of the neonatal kidney is even greater. It must maintain a positive salt balance for growth while the neonate is fed a diet that is very low in sodium. This review focuses on how the neonatal kidney reabsorbs NaCl with a special emphasis on the differences between the neonatal and adult kidney.

EFFECT OF SKI-RACE ON HEMOGLOBIN CONCENTRATION AND HEMATOCRIT IN ELITE CROSS-COUNTRY SKIERS

1764 International Ski Federation has a rule to exlude men with hemoglobin concentration (Hb) above 185 g·l-1 and women with 165 g·l-1 from race to avoid possible health risks and observed extreme manipulation with Hb-mass. It has been argued that water loss during race would increase Hb and give false positive results if Hb is measured after the race. In the Finnish Championships the effect of 10 km (n=17) and 50 km(n=12 finished+6 broke off) ski-race on Hb and hematocrit (Hct) was studied in elite male cross-country skiers (age 24±4 yrs, VO2max 78±5 ml·kg-1 ·min-1). Venous blood samples were taken 120-45 min before as well as 15 and 60 min (10 km) or 15-60 min (50 km) after the ski-race and Hb (g·l-1), Hct (%), total protein content (S-Prot, g·l-1) and erythropoietin (S-EPO, mU·ml-1) were analysed. TableTableFrom pre to post60min the fluid intake was 0.9±0.3 l (10 km) and 2.7±0.8 l (50 km). Six skiers who broke off the 50 km race after 25±10 km drank 1.1±0.6 l and had similar Hb and Hct changes as those who finished the race. We conclude that sampling after the race would not give false positive Hb-values and that the decrease may be due either to shifts in intra- and extracellular fluid balance and/or to fluid intake.

Renal sodium excretion in normal aging: Decreased excretion rates lead to delayed handling of sodium loads

Disorders of extracellular fluid balance including congestive heart failure and dehydration are prevalent in elderly patients. Aging itself is associated with changes in renal physiology that may predispose to these conditions. Current data regarding the ability of healthy elderly subjects to excrete sodium following a sodium challenge is incomplete, particularly for sodium challenges common in daily life. To define the patterns of renal sodium excretion in normal aging, we examined renal sodium excretion rates in a 24-hour period following two hour intravenous administration of several doses of sodium. Each subject was studied on four different occasions separated by at least two weeks. Over the four studies each subject received the following four saline infusions: (a) hypotonic infusion of 0.45% saline at 100 ml/hour for 2 hours; hypertonic saline infusions (5% saline) at a rate of (b) 0.025 ml · kg−1 · min−1; (c) 0.04 ml · kg−1 · min−1; and (d) 0.06 ml · kg−1 · min−1 for 2 hours. Significant differences were seen in the patterns of sodium excretion over time: in young subjects an initial high rate of sodium excretion versus a lower initial sodium excretion was observed while the old displayed a prolonged sodium excretory pattern. It is concluded that age-related delays in renal sodium excretory capacity are likely to be of clinical significance during states of sodium excess.

Sodium sensitivity of blood pressure.

A variety of techniques have been used by different investigators to characterize blood pressure responses to changes in sodium balance. Despite the arbitrary nature of the definition of salt sensitivity, many of these studies have demonstrated consistency in the factors associated with the heterogeneous responses to the methods used. This review surveys current approaches to the assessment of blood pressure responsivity to alterations in sodium and extracellular fluid balance in normotensive as well as hypertensive humans. In addition, new observations related to the possible mechanisms involved are highlighted.

Enhanced monoamine release in the median preoptic area following reduced extracellular fluid volume in rats

The role of monoaminergic neural inputs to fluid regulatory systems in the median preoptic nucleus (MnPO) was investigated by examination of monoamine metabolism during reduction of systemic extracellular fluid volume in freely moving rats. Extracellular fluid volume was decreased iso-osmotically by subcutaneous polyethylene glycol (PEG), and extracellular noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) were measured using intracerebral microdialysis techniques. PEG treatments significantly increased NA, DA and DOPAC release in the MnPO area. The results suggest that monoaminergic neural systems in the region of the MnPO are important in the control of extracellular fluid balance.

Localization of central nervous system structures mediating extracellular thirst in the female rat.

Water intake elicited by microinjection of the hormone angiotensin-II into the preoptic region of cyclic female rats was significantly less on days of vaginal oestrus than at dioestrus or metoestrus, whereas the drinking of 2.7% NaCl solution, to which rats also had access, did not vary with the cycle. Administration of the same dose of angiotensin-II to the subfornical organ and the lateral cerebral ventricles induced drinking at all stages of the oestrous cycle, but the volumes of water or 2.7% NaCl ingested did not vary with the cycle. Water intake after subcutaneous injection of isoprenaline, a beta-adrenergic agonist which causes increased angiotensin biosynthesis, varied cyclically with the stage of the oestrous cycle. On the other hand, water and 2.7% NaCl intakes induced by intraperitoneal injection of hypertonic NaCl (a cellular stimulus of thirst) or by 24-h water deprivation (which dehydrates both the extracellular and cellular body fluid compartments) did not differ significantly at the various stages of the oestrous cycle. The finding that fluctuations in angiotensin- and isoprenaline-induced water intake parallel the changes in spontaneous 24-h drinking suggests that the preoptic region may play an important role in the maintenance of extracellular fluid balance in synchrony with the oestrous cycle.

Neuroendocrine mechanisms mediating fluid intake during the estrous cycle

Gonadal steroids appear to influence fluid-electrolyte homeostasis through behavioral as well as renal mechanisms. The marked fluctuations in drinking behavior observed during the estrous cycle of the female rat may be due to an interaction between estrogen and the dipsogenic peptide hormone, angiotensin II, at the level of basal forebrain receptors. The preoptic region in particular may play an important integrative role in the maintenance of extracellular fluid balance in synchrony with the estrous cycle, since it contains receptors for angiotensin and estrogen. Prolactin may also directly participate in mechanisms of extracellular thirst, while an exact role for vasopressin has yet to be established. Recent studies also suggest that estrogens may influence body fluid regulation by interacting with several neurotransmitters, including serotonin. dopamine and noradrenaline.

The Lymphatic System

This article on the lymphatics was undertaken for three reasons: The first is to recount the story of the rediscovery of these vessels in the 17th century and briefly review the subsequent events leading up to our present knowledge of the lymphatic system. The second is to emphasize the role of the lymphatics in maintaining extracellular fluid balance, in the removal of protein, fat, and other substances of large molecular size from the tissue spaces, and in the circulation of the lymphocytes from their germinal centers and storage depots to all parts of the body via lymphaticovenous connections. The third reason is to suggest that the responsibility for maintaining the transport function of the lymphatics properly belongs to the vascular surgeon.

Dysfunction of the Adrenal Gland: Physiologic Considerations and Nursing Problems

The adrenal gland, actually comprised of two glands, exerts widespread, and at times, critically important physiologic effects. The adrenal cortex, by secreting glucocorticoids, mineralocorticoids, and sex hormones has an impact upon intermediate metabolism, extracellular fluid balance, and secondary sexual characteristics, respectively. Adequate function of the adrenal cortex is essential for the body to adequately cope with stress. By secreting the catecholamines epinephrine and norepinephrine, the adrenal medulla reinforces the function of the sympathetic nervous system, thus facilitating physiologic readiness for the “fight or flight” response. Adrenocortical insufficiency (Addison's disease) predisposes the patient to physiologic collapse (addisonian crisis) in the presence of seemingly minor insults. An inability to maintain blood glucose and hypotension reflect a deficiency in glucocorticoid secretion, whereas the depletion of extracellular fluid and hyperkalemia are the result of a deficient output of mineralocorticoids. Cushing's syndrome occurs as a result of excessive plasma levels of glucocorticoid. Protein catabolism is pronounced and produces thin, weak extremities and osteoporosis. Abnormal distribution of fat leads to the characteristic signs of truncal, facial (“moon-faced” appearance), and interscapular (“buffalo hump”) obesity. The accompanying hyperglycemia and the increased risk for the development of diabetes mellitus are caused by the anti-insulin and gluconeogenic effects of glucocorticoids. Excessive secretion of mineralocorticoids (aldosteronism) produces an expanded extracellular fluid volume with hypertension and hypokalemia. Hypernatremia occurs because of a true excess of sodium coupled with deficit of free water. This deficit of free water occurs because of hypokalemic nephropathy with resultant loss of renal concentrating ability. Pheochromocytomas are autonomous, secreting tumors of the adrenal medulla that produce inappropriate and excessive levels of circulating catecholamines. The clinical picture commonly involves severe hypertension of either a constant or paroxysmal nature. Hypermetabolism and hypercatabolism, which are characteristic of the stress response, also occur. The problems encountered in the care of individuals with adrenal dysfunction are direct outgrowths of the physiologic effects of insufficient or excessive adrenal hormones. The diffuse nature of the physiologic abnormalities produces a wide variety of disorders. A thorough understanding of normal adrenal physiology greatly facilitates the anticipation of and the appropriate nursing intervention in these problems.

Initial experiences with continuous ambulatory peritoneal dialysis.

Continuous ambulatory peritoneal dialysis (CAPD) has been initiated on 51 patients: 27 females (mean age -- 43.9 years) and 24 males (mean age -- 46.4 years). This group has been observed for a total of 1420 patient weeks of treatment (27.3 patient years). Thirty-six episodes of peritonitis have been noted among 19 patients. The overall incidence was one episode per 39.4 patient weeks. Recurrent episodes of peritonitis resulted in discontinuation of CAPD in five (9.8%) of the patients. Three (5.9%) of the patients were unable to continue with CAPD because of its inability to control extracellular fluid balance. In the patients who transferred from intermittent peritoneal dialysis to CAPD, there was a 4.5 mg/dl drop in serum creatinine and a 34 mg/dl drop in mean BUN values. There was a rise of approximately 2 gm in the hemoglobin levels of this group of patients. If the problem of peritonitis can be solved, CAPD will become the dialytic treatment of choice for the majority of patients with end-stage renal disease.

Ineffectiveness of carob flour in infantile diarrhea.

THERAPEUTIC control of diarrhea have for many years included the use of a vast array of vegetable derivatives containing pectin and lignin. These complex carbohydrate substances have been clearly shown to exert a distinct effect upon the character of the diarrheal stool. This effect upon the appearance and consistency of the stool has been construed to indicate an effect upon the course of the diarrheal disease state. Inasmuch as the chief effects of the latter are fluid and electrolyte loss and a resultant alteration in intra- and extra-cellular fluid balance, an evaluation of the effect of such therapy in diarrhea should be based upon a determination of the degree to which fluid and electrolyte loss is inhibited rather than upon an alteration in the character of the stool. Such an evaluation of a controlled series of 47 cases of etiologically related infantile diarrhea designed to determine the effect of pectin