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PubMed1985

Inspiratory airway obstruction does not affect lung fluid balance in lambs.

The purpose of this study was to examine the effects of inspiratory airway obstruction on lung fluid balance in newborn lambs. We studied seven 2- to 4-wk-old lambs that were sedated with chloral hydrate and allowed to breathe 30-40% O2 spontaneously through an endotracheal tube. We measured lung lymph flow, lymph and plasma protein concentrations, pulmonary arterial and left atrial pressures, mean and phasic pleural pressures and airway pressures, and cardiac output during a 2-h base-line period and then during a 2- to 3-h period of inspiratory airway obstruction produced by partially occluding the inspiratory limb of a nonrebreathing valve attached to the endotracheal tube. During inspiratory airway obstruction, both pleural and airway pressures decreased 5 Torr, whereas pulmonary arterial and left atrial pressures each decreased 4 Torr. As a result, calculated filtration pressure remained unchanged. Inspiratory airway obstruction had no effect on steady-state lung lymph flow or the lymph protein concentration relative to that of plasma. We conclude that in the spontaneously breathing lamb, any decrease in interstitial pressure resulting from inspiratory airway obstruction is offset by a decrease in microvascular hydrostatic pressure so that net fluid filtration remains unchanged.

Airway Obstruction↗
PubMed2000

Interface Properties of Circumventricular Organs in Salt and Fluid Balance.

The "sensory" circumventricular organs, with their leaky blood-brain barriers, permit contact between brain neurons and blood-borne molecules. Body fluid balance and cardiovascular control involve established interface functions of subfornical organs. Their recently identified target functions for hormones released during digestion suggest that they may coordinate fluid and food intake.

Journal Article↗
PubMed2001

Reversible temperature-sensitive alterations in lung fluid balance.

Hypothermia is intentionally imposed during the harvesting of lungs for transplantation. The aim of this study was to investigate the fluid balance alterations in rat lung preparations exposed to hypothermic perfusion. Lowering perfusate temperature from 37 degrees C to values between 27 and 7 degrees C caused an immediate, marked pulmonary hypertension and vasoconstriction accompanied by rapid development of pulmonary edema (+1.15 g, or approximately 90%, gain in lung weight within 5 min). However, on rewarming, vasoconstriction was immediately reversed. Edema was resolved, but along a two-component time course: an immediate reduction of lung weight on rewarming (t 1/2 of 0.5 min) that mirrored the recovery of pulmonary artery pressure and vasoconstriction, and also a slower pressure-independent component of recovery (t 1/2 of 3.5 min). Ouabain (300 microM) markedly inhibited the lung's ability to recover from edema, indicating that fluid clearance from lung tissue was the result of activation of ouabain-sensitive (Na+,K+)-ATPase pump. Results could not be explained by vascular or airspace injury as lung sections from hypothermic lungs appeared normal. The findings indicate that hypothermia induces pulmonary edema formation, which can be rapidly cleared upon rewarming by activation of ouabain-sensitive (Na+,K+)-ATPase pump. Thus, impaired fluid clearance from lung extravascular spaces may be a critical factor limiting gas exchange in transplanted lungs exposed to hypothermia.

Animals↗
PubMed1995

The effect of bilateral fetal adrenalectomy on fluid balance in the ovine fetus.

1. Bilaterally adrenalectomized adult sheep, taken off replacement therapy, exhibit decreased plasma sodium, and increased plasma potassium, urinary sodium excretion and urinary sodium:potassium ratio. The hypothesis tested was that these effects would not be seen in adrenalectomized ovine fetuses, due to the mother being the major regulator of fetal fluid balance. 2. The fetuses of seven Merino ewes were bilaterally adrenalectomized at 120 +/- 0.3 days of gestation (term is 150 days) and a bladder cannula inserted. Urine flow and composition were measured six times between 125 and 142 days of gestation, and compared with results in seven control fetuses at the same gestational ages. At between 142 and 145 days of gestation, blood samples were taken from the ewe and fetus, they were killed and the volume and composition of amniotic and allantoic fluids measured. 3. Adrenalectomized fetuses had significantly lower (P < 0.05) plasma aldosterone concentration than that observed in intact fetuses (adrenalectomized, 92 +/- 16 pmol l-1; intact, 224 +/- 46 pmol l-1; P < 0.001). Plasma cortisol level was also lower (adrenalectomized, 8.6 +/- 1.4 nmol l-1; intact, 110.3 +/- 24.8 nmol l-1). Maternal plasma steroids were similar in both groups. 4. There were no significant differences in fetal urine flow rate, osmolality or composition until 139-142 days of gestation. At this time urine sodium:potassium ratio was significantly greater in adrenalectomized (P < 0.05) than intact fetuses. 5. There were no significant differences in maternal or fetal plasma solutes in the two groups and only minor alterations in the volume and composition of amniotic and allantoic fluid. The conclusion is that the major determinant of fetal fluid and electrolyte balance is placental transfer of water and electrolytes from the mother.

Adrenal Cortex↗
PubMed1993

Progesterone reduces sympathetic tone without changing blood pressure or fluid balance in men.

There is scant information on the effects of progesterone on circulation. Changes in catecholamine levels, blood pressure and transcapillary fluid balance were measured in 12 men before and during administration of natural progesterone (Utrogestan). Before administration, systolic blood pressure was significantly correlated with venous adrenaline (r = 0.67, p = 0.01). There was a significant decrease (p = 0.004) in venous noradrenaline during progesterone administration, and systolic blood pressure was significantly correlated with the arteriovenous difference for noradrenaline (r = 0.66, p = 0.02). Serum progesterone, which attained levels similar to those found in women during the luteal phase, did not significantly alter blood pressure, body weight or intra- to extravascular fluid shift. It is concluded that progesterone may have a direct action by increasing the uptake of noradrenaline from the synaptic cleft or by decreasing the nerve firing rate. Interestingly, the pretreatment finding of a significant correlation between blood pressure and adrenaline was less evident during progesterone administration.

Adult↗
PubMed2000

A comparison of arginine vasopressin levels and fluid balance in the perinatal period in infants who did and did not develop chronic oxygen dependency.

Arginine vasopressin (AVP) levels on days 1, 3 and 5 and fluid balance in the perinatal period were assessed in 60 infants, median gestational age 27 weeks (range 24-33). Fluid input and output, urine osmolality and episodes of hyponatraemia were recorded on a daily basis. Forty-one infants subsequently developed chronic lung disease (CLD), they were more immature, of lower birthweight and had higher AVP levels on days 3 and 5 (p < 0.05) than the rest of the cohort. Despite similar levels of fluid input, compared to the non-CLD infants, those who developed CLD had higher urine osmolalities on days 1, 5, 6 and 7 (p < 0.05), but there were not significant differences between the two groups regarding urine output or episodes of hyponatraemia. Logistic regression analysis revealed AVP levels on day 3 were significantly correlated with the duration of oxygen dependency independent of other factors. We conclude elevated AVP levels in the perinatal period are associated with CLD development, but our results suggest they have little functional significance.

Arginine Vasopressin↗
PubMed1995

Disorders of body fluid balance: a new look into the mechanisms of disease.

OBJECTIVE: To review the mechanisms of disease on the basis of dysfunction in body fluid distribution secondary to abnormalities in capillary permeability and plasma membrane transport disorders, leading to quantitative and qualitative alterations of the interstitial space, a mainly strategic compartment positioned between the microcirculation and cell mass. DATA SOURCES: The recent literature on the mechanisms involved in the control of body fluid balance, with special reference to microcirculation and interstitial compartment physiology, as well as published and unpublished original data from the authors laboratory. DATA EXTRACTION AND SYNTHESIS: To illustrate the importance of capillary permeability dysfunction in the development of disease, animal (rat and dog) models of chronic renal failure, acute diuretic-induced fluid depletion, diabetes mellitus, arterial hypertension and ischemia-reperfusion of the kidney were used in an attempt to show that in all these experimental models, basic capillary permeability dysfunction (measured by the extravasation of Evans blue, a marker of albumin leakage) develops in specific microcirculation beds. As a consequence, tissue edema (interstitial and/or cellular) develops and likely impairs the traffic of nutrients and waste products to and from the cellular mass, and/or challenges the microcirculation, leading to organ damage. Kidney dysfunction is measured by conventional clearance methods (renal hemodynamics and tubular function). In some models, the eventual mediators of vascular abnormality are examined by use of pharmacological tools. CONCLUSIONS: The critical role of microcirculation dysfunctions, in particular capillary permeability, resulting in interstitial compositional changes is presented as the basis of disease. The apparent specificity of target organ damage may represent the nonspecific result of physicochemical alteration in the strategic interstitial fluid compartment.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

The recovery of the fluid balance after hemodialysis and hemofiltration.

Dialysis dysequilibrium syndrome is a frequent complication of renal replacement therapy and seems to be related to changes in fluid balance. From previous studies it is known that these changes are less pronounced during hemofiltration (HF), leading to a lower incidence of complaints compared to hemodialysis (HD). To assess the severity and duration of the dysequilibrium syndrome, intracellular (ICV) and extracellular fluid volumes (ECV) were measured during and after HD and HF by means of a non-invasive conductivity method. Blood volume changes were calculated from pre- and post-treatment erythrocyte counts. Seven HD and eight HF patients were studied. Ultrafiltration volume did not differ between both groups. Blood volume decrease was less during HF due to a significant decrease in ICV, the latter being in contrast to an ICV increment during HD. The significant decrease in ICV led to a less severe decrease in ECV (90 versus 85%). Overall, this resulted in a better vascular refill during HF. At the end of treatment ICV and ECV were not in equilibrium yet. During the recovery period ICV increased roughly 3% in the HF group. In the HD group some patients showed an increase while others showed a decrease in ICV. Overall, no change in ICV was noticed. During recovery ECV decreased further in both groups. The measured recovery period was significantly shorter after HF (245 +/- 68 min) than after HD (299 +/- 37), supporting the hypothesis that HF is a more physiological way of treatment compared to HD.

Aged↗
PubMed2006

Transcapillary fluid balance consequences of missing initial lymphatics studied in a mouse model of primary lymphoedema.

To investigate the phenotypic consequences of a deranged lymphangiogenesis in relation to tissue fluid accumulation and the possible role of inflammation in the pathogenesis of lymphoedema, we measured determinants of transcapillary fluid filtration and inflammatory mediators in the interstitial fluid in genetically engineered Chy mice, a model for primary congenital lymphoedema (Milroy's disease). Although initial lymphatics were not present in dermis in any of the areas studied (fore paw, hind paw, thigh and back skin) interstitial fluid pressure (P(if)), measured with micropipettes, and tissue fluid volumes were significantly increased only in the areas with visible swelling - the fore and hind paw, whereas interstitial colloid osmotic pressure (COP(if)) was increased in all the skin areas examined. A volume load of 15% of body weight resulted in a more pronounced increase in P(if) as well as a four-fold increase in interstitial fluid volume in Chy relative to wild-type (wt) mice, showing the quantitative importance of lymphatics for fluid homeostasis during acute perturbations. A similar level of proinflammatory markers in interstitial fluid in early established lymphoedema (3-4 months) in Chy and wt suggests that inflammation does not have a major pathogenetic role for the development of lymphoedema, whereas a reduced level of the immunomodulatory cytokine interleukin (IL)-4 may result in a reduced immunological defence ability and thus lead to the increase in inflammatory cytokines IL-2 and IL-6 observed at a later stage (11-13 months). Our data suggest that primary lymphoedema results in a high interstitial fluid protein concentration that does not induce an interstitial inflammatory reaction per se, and furthermore shows the paramount importance of the initial lymphatics in tissue fluid homeostasis, especially during perturbations of transcapillary fluid balance.

Animals↗
PubMed2002

Impact of stepped verbal and written reinforcement of fluid balance advice within an outpatient haemodialysis unit: a pilot study.

BACKGROUND: The present pilot study assesses a programme of verbal and written fluid balance advice within an out-patient haemodialysis unit. METHODS: Twenty-one haemodialysis patients were followed over three separate 6-week periods. Each 6-week period assessed dietetic and nursing educational input using a stepped approach with interdialytic weight gain (IDWG) as a barometer of patient compliance. Weight gain was statistically examined using the non-parametric Friedman test. RESULTS: Forty-eight per cent of the sample group demonstrated an overall improvement in mean weight gain; however, this was not statistically significant (P=0.504). CONCLUSION: The pilot study suggests that further studies with greater numbers and a control group would have a useful contribution to make in this field.

Adult↗
PubMed1999

Drink composition, voluntary drinking, and fluid balance in exercising, trained, heat-acclimatized boys.

This study examined the effects of beverage composition on the voluntary drinking pattern, body fluid balance, and thermoregulation of heat-acclimatized trained boys exercising intermittently in outdoor conditions (wet bulb globe temperature 30.4 +/- 1.0 degreesC). Twelve boys (age 13.4 +/- 0.4 yr) performed two 3-h sessions, each consisting of four 20-min cycling bouts at 60% maximal aerobic power alternating with 25-min rest. One of two beverages was assigned: unflavored water (W) or flavored water plus 6% carbohydrate and 18 mmol/l Na (CNa). Drinking was ad libitum. Total intake was higher (P < 0.05) during CNa (1,943 +/- 190 g) compared with W (1,470 +/- 143 g). Euhydration was maintained with CNa (+0.18% body wt), but a mild dehydration resulted with W (-0.94% body wt; P < 0.05). Sweat loss, much higher than previously published for children of similar age, was similar between conditions (CNa = 1,644.7 +/- 117.5; W = 1,750.2 +/- 152.7 g). The increase in rectal temperature (CNa = 0.86 +/- 0.3; W = 0.76 +/- 0.1 degreesC), heart rate, and all perceptual variables did not differ between conditions. In conclusion, a flavored carbohydrate-electrolyte drink prevents voluntary dehydration in trained heat-acclimatized boys exercising in a tropical climate despite their large sweat losses. Because hydration changes were minor, the thermoregulatory strain observed was similar between conditions.

Acclimatization↗
PubMed1982

Sodium balance, fluid homeostasis and the renin-aldosterone system during the prolonged exercise of hill walking.

1. The effect of 5 consecutive days of hill walking on electrolyte balance, fluid homeostasis, plasma renin activity and plasma aldosterone concentration was studied in five male subjects. 2. The 5-day exercise period was preceded by a 4-day control period and followed by a 4-day recovery period. Throughout the 13-day study subjects ate a fixed diet. 3. After 5 days of exercise subjects had retained a mean of 264 mmol (SD 85) of sodium. Plasma sodium concentration remained constant at 142.0 mmol/l (SD 5.4). This indicates an expansion of the extracellular space by 1.84 litres. 4. By the end of the exercise period there was a positive water balance of about 0.9 litre. Thus there was a net movement of 0.94 litre of fluid from the intracellular to the extracellular space. 5. Packed cell volume decreased from a mean of 43.5% to 37.9% after 5 days of exercise, indicating that about 0.9 litre of the extracellular fluid entered the vascular compartment. The remaining fluid may be responsible for the significant increase in lower leg volume. 6. During the exercise period plasma aldosterone concentration and plasma renin activity rose, and there was a highly significant correlation between these values and the sodium retention. There was also a significant correlation between sodium retention and the increase in leg volume, which suggests that oedema may be the result of prolonged exercise of this type.

Adult↗
PubMed1988

Effect of progressive exercise on lung fluid balance in sheep.

The purpose of this study is to determine the roles of cardiac output and microvascular pressure on changes in lung fluid balance during exercise in awake sheep. We studied seven sheep during progressive treadmill exercise to exhaustion (10% grade), six sheep during prolonged constant-rate exercise for 45-60 min, and five sheep during hypoxia (fraction of inspired O2 = 0.12) and hypoxic exercise. We made continuous measurements of pulmonary arterial, left atrial, and systemic arterial pressures, lung lymph flow, and cardiac output. Exercise more than doubled cardiac output and increased pulmonary arterial pressures from 19.2 +/- 1 to 34.8 +/- 3.5 (SE) cmH2O. Lung lymph flow increased rapidly fivefold during progressive exercise and returned immediately to base-line levels when exercise was stopped. Lymph-to-plasma protein concentration ratios decreased slightly but steadily. Lymph flows correlated closely with changes in cardiac output and with calculated microvascular pressures. The drop in lymph-to-plasma protein ratio during exercise suggests that microvascular pressure rises during exercise, perhaps due to increased pulmonary venous pressure. Lymph flow and protein content were unaffected by hypoxia, and hypoxia did not alter the lymph changes seen during normoxic exercise. Lung lymph flow did not immediately return to base line after prolonged exercise, suggesting hydration of the lung interstitium.

Animals↗
PubMed2002

Assessment of fluid balance by measurement of skin tissue thickness during clinical anaesthesia.

STUDY OBJECTIVE: To determine if measuring skin tissue thickness by a recently developed 10 MHz ultrasound scan may be used as a valuable parameter to guide fluid therapy and detect fluid shifts to the extravascular space during surgical procedures in addition to central venous pressure (CVP). STUDY DESIGN: Prospective, clinical and observational study. SETTING: An operation theatre of the Ear Nose Throat (ENT) department of an university hospital. PATIENTS: Following approval by the local ethics committee 12 otherwise healthy male patients undergoing ENT surgery for oropharyngeal carcinoma were involved in this study. The patients stayed nil per os for 10 h before induction of anaesthesia. INTERVENTIONS/MEASUREMENTS: Crystalline fluids (Ringer's solution) were supplied at a constant rate of 10 ml kg-1 bw h-1. Patients were kept in the supine position during surgery, no further interventions were performed. Additional to routine monitoring, tissue thickness (TT) of proximal pre-tibial skin and CVP were measured every 30 min, haematocrit was determined hourly for 5 h starting at t0. MAIN RESULTS: Haematocrit constantly declined during the observation period, showing a significant difference in t0 after 120 min. The increase in TT was strongly correlated with intraoperative positive fluid balance (r=0.96), while the course of CVP did not reflect the amount of fluid application comparably. CONCLUSIONS: Non-invasive determinations of skin tissue thickness by the presented ultrasonic device appears to give additional information on fluid intake and distribution during clinical anaesthesia.

Aged↗
PubMed1979

Effect of heparin or fibrinogen depletion on lung fluid balance in sheep after emboli.

Investigators have proposed that fibrinogen, fibrin, or their degradation products are essential for the increased lung vascular permeability to fluid and protein that may occur after microemboli. To test this hypothesis, we used 20 anesthetized ventilated sheep in which we measured lung lymph flow, pulmonary artery and left atrial pressures, thermodilution cardiac output, and lymph/plasma protein concentrations. We injected glass bead microemboli (200 micrometers diam) sufficient to raise pulmonary vascular resistance to three times base-line values and cause increased lung lymph flow with a parallel increase in protein clearance, which is characteristic of increased lung vascular permeability. Neither large doses of heparin (3,000 U/kg) nor fibrinogen depletion with viper venom (ancrod, 2 U/kg), by themselves, affected steady-state pulmonary hemodynamics or lung fluid balance. These treatments prior to giving sufficient amounts of emboli to triple the pulmonary vascular resistance did not prevent the increased lung vascular permeability. We conclude that neither fibrin deposition nor degradation are essential to microembolic lung vascular injury in sheep.

Ancrod↗
PubMed1981

Comparison of the effects of saline and homologous plasma infusion on lung fluid balance during endotoxemia in the unanesthetized sheep.

The effects of saline infusion (20 ml/kg/30 minutes) and homologous plasma infusion (20 ml/kg/30 minutes) on the lung fluid balance during increased pulmonary capillary permeability secondary to Escherichia coli endotoxin infusion (1 microgram/kg/15 minutes) were studied in unanesthetized sheep. Saline and homologous plasma infusion increased lung lymph flow by 10.6% and 10.8%, respectively. The bloodless wet-to-dry ratio was 5.1 +/- 0.2 in the saline group and 5.2 +/- 0.2 in the homologous plasma group. The saline infusion decreased the plasma oncotic pressure while the plasma infusion increased plasma oncotic pressure. However, the increase in plasma oncotic pressure was negated by concomitant changes in the lymph oncotic pressure and greater increases in pulmonary microvascular pressure during the plasma infusion. Changes in pulmonary microvascular pressure predominated over changes in the oncotic pressure gradient. Both saline and homologous plasma infusion increase fluid filtration into the interstitial space by the same magnitude. Therefore neither has a clear advantage in the treatment of pulmonary edema during increased permeability.

Animals↗
PubMed1996

Long-Term Treatment with Oral Torsemide and Its Effect on Body Weight and Fluid Balance in Patients with Chronic Renal Insufficiency.

Long-term treatment with oral torsemide was studied to determine its effectiveness in maintaining steady-state fluid balance in patients with chronic renal insufficiency by using a placebo-controlled, double-blind, random-off design. Patients with stable chronic renal insufficiency were initially titrated and then stabilized on torsemide. Once stabilized on torsemide, patients were randomly assigned in a double-blind fashion to continue on their titrated dose of torsemide or to receive a placebo. Of the 82 patients enrolled in the study, 68 were randomized to torsemide (n = 34) or placebo (n = 34). Patients who received the placebo showed a significantly greater (p < 0.001) mean increase in body weight (3.55 lb) than did patients who remained on torsemide (0.46 lb). Approximately two-thirds of the weight gain observed in the placebo group occurred during the first 3 days after randomization. Patients continued to receive treatment unless they developed fluid accumulation that was considered deleterious to their clinical state as determined by the investigator. In the placebo group a greater number of patients discontinued treatment because of weight gain or fluid accumulation. The mean number of days on treatment after randomization was significantly higher (p < 0.001) for patients who received torsemide (26 days) than for patients who received the placebo (16 days). The lack of weight gain in the torsemide group was associated with a higher percentage of patients who showed no change or an improvement in peripheral edema status (79%) than in placebo patients (35%). No patient was withdrawn from the study because of hyperkalemia or hypokalemia. The adverse effects reported during the study were as anticipated for patients with chronic renal insufficiency that is often complicated by other underlying illnesses.

Journal Article↗
PubMed1993

Rowing performance, fluid balance, and metabolic function following dehydration and rehydration.

Eight international class lightweight rowers were examined to determine the efficacy of rehydrating with water following 24 h of dehydration on body fluid balance, metabolic function, and rowing performance. The rowers performed a maximal rowing trial on a Gjessing rowing ergometer (4200 revs, 3-kg resistance) while euhydrated (ET) and following partial rehydration (RT). Body weight was reduced using exercise together with food and fluid restriction over 24 h and was followed by consumption of 1.5 l of water over 2 h. Body weight decreased 5.16 +/- 0.14% (P < 0.05) and plasma volume decreased 12.5 +/- 1.4% (P < 0.05) after dehydration. Rehydration restored plasma volume by 6.02 +/- 0.62%. Rowing trial time increased significantly from 7.02 +/- 0.17 min for the ET to 7.38 +/- 0.21 min for the RT (P < 0.05). The net plasma lactate accumulation decreased significantly from 8.77 +/- 0.31 mmol.l-1 for the ET to 6.77 +/- 0.24 mmol.l-1 for the RT (P < 0.05). Glycogen content (glycosyl units) of the vastus lateralis decreased by 203.6 +/- 18.6 mmol.kg-1 DW during the ET compared with 139.9 +/- 13.4 mmol.kg-1 DW during the RT (P < 0.05). These results demonstrate that the dehydration/rehydration protocol reduced maximal rowing performance due to lowered plasma volume and decreased muscle glycogen utilization.

Adult↗