Body Water Volume Research Articles

Effects of proprioceptive neuromuscular facilitation stretching and deep-breathing exercises on upper extremity lymphedema in stroke patients.

[Purpose] The purpose of this study was to determine the effects of deep-breathing and proprioceptive neuromuscular facilitation stretching exercises on upper limb lymphedema in stroke patients. [Subjects and Methods] The study consisted of 10 patients with lymphedema that had occurred after stroke. Neurodevelopmental treatment was applied in the same manner as that used for the existing treatment. The subjects performed deep-breathing and stretching exercises three times per week for 4 weeks (12 sessions total). Body water volume in the upper limbs was measured before and after exercise by using an InBody S10 analyzer. [Results] Performance of deep-breathing and stretching exercises significantly reduced body water volume in both the affected and unaffected arms. The extracellular-to-total cellular fluid volume ratio in the affected arm improved to 0.379 after exercise, although this change was not significant. [Conclusion] The results of the present study show that deep-breathing and proprioceptive neuromuscular facilitation stretching exercises reduce upper extremity lymphedema in stroke patients.

Safety, Tolerability, and Pharmacokinetic Properties of Intravenous Delafloxacin After Single and Multiple Doses in Healthy Volunteers

PurposeThe objective of this report was to determine the pharmacokinetic properties, safety, and tolerability of single and multiple doses of intravenous delafloxacin. In addition, the absolute bioavailability (BA) of the 450-mg tablet formulation of delafloxacin was determined. MethodsThree clinical trials are summarized. The first study was a randomized, double-blind, placebo-controlled, single- (300, 450, 600, 750, 900, and 1200 mg) ascending-dose study of IV delafloxacin in 62 (52 active, 10 placebo) healthy volunteers. The second study was a randomized, double-blind, placebo-controlled study of IV delafloxacin (300 mg) given as a single dose on day 1, followed by twice-daily dosing on days 2 through 14; 12 (8 active, 4 placebo) healthy volunteers were enrolled. The third study was an open-label, randomized, 2-period, 2-sequence crossover study in which 56 healthy volunteers were randomly assigned to 1 of 2 sequences of a single oral dose of delafloxacin (450-mg tablet) or IV delafloxacin (300 mg). Serial blood samples were collected, and plasma pharmacokinetic parameters of delafloxacin were calculated. FindingsDelafloxacin Cmax values increased proportionally with increasing single IV dose for the dose range of 300 to 1200 mg, whereas the AUC values increased more than proportionally to dose for the same dose range. The mean terminal half-life of delafloxacin was approximately 12 hours (ranging from 8 to 17 hours). The volume of distribution (Vd) at steady state was approximately 35 L, which is similar to the volume of total body water. There was minimal accumulation of delafloxacin after twice-daily IV administration of 300 mg with an accumulation ratio of 1.09. The delafloxacin total exposure after a single 1-hour IV infusion of 300 mg and a single oral dose of a 450-mg tablet were equivalent with geometric least square mean ratio (90% CI) of 0.8768 (0.8356–0.9200) for AUC0–∞ and 0.8445 (0.8090–0.8815) for AUC0–t, respectively. The Cmax values of delafloxacin were not equivalent for the 2 formulations with a ratio (90% CI) of 0.5516 (0.5150–0.5908), respectively. The mean absolute bioavailability of delafloxacin was 58.8%. ImplicationsDelafloxacin was well tolerated in healthy volunteers after single and multiple IV doses. The total systemic exposure to IV (300 mg) and oral (450 mg) delafloxacin is comparable, supporting that a switch between the 2 formulations is appropriate.

English

Creatine monohydrate (CrM) is considered a safe nutritional supplement. The loading phase of CrM supplementation is associated with shifts in total body water and plasma volume that may affect blood pressure. However, few studies have measured blood pressure during the loading phase of CrM supplementation. Purpose: The aim of this study was to determine if CrM supplementation in normotensive college-aged males induces a daily blood pressure increase during the supplementation-loading phase. Methods: Participants’ blood pressure, shoulder extension active range of motion (AROM), arm girth, arm volume, plasma volume, blood volume, hematocrit, and hemoglobin were measured daily for five days of supplementation (4x5gxd -1 x5d) of either CrM (n=12) or placebo (P; n=12). Results: The CrM group did not experience significant changes in systolic blood pressure (mmHg) (CrM 126.67±1.94 Day5 ; P 125.50±2.61 Day5 ) or diastolic blood pressure (mmHg) (CrM 83.83±2.19 Day5 ; P 82.33±2.07 Day5 ) compared to P. A significant T x Tx interaction (p=0.001) and Tx effect (p=0.03) support decreased AROM (cm) in the CrM group compared to P (CrM 38.3±2.19 Day 1 , CrM 34.0±2.01 Day5 ; P 41.02±2.49 Day 1 , P 43.2±2.47 Day5 ). An increase in arm volume (ml) in the CrM group (CrM 2443±99.44 Day 1 , CrM 2470±92.21 Day5 ) vs. the P group (P 2372±74.44 Day 1 , P 2374±74.61 Day5 ; p=0.026) was observed. An increase in plasma volume (%Δ from baseline) (p=0.014) (CrM 1.48±2.60 Day2 , CrM 6.03±4.03 Day5 ; P 3.25±2.74 Day2 , P 5.05±2.91 Day5 ) and a decrease in hematocrit (%) (p=0.026) (CrM 0.47±0.01 Day 1 , 0.45±0.01 Day5 ; P 0.46±0.01 Day 1 , 0.45±0.01 Day5 ) were observed. Conclusion: Findings suggest CrM supplementation in the loading phase does not affect blood pressure in normotensive college-aged males. CrM reduces shoulder extension AROM presumably due to increased tissue volume secondary to fluid shifts.

Leptin and energy restriction induced adaptation in energy expenditure

BackgroundDiet-induced weight loss is accompanied by adaptive thermogenesis, i.e. a disproportional reduction of resting energy expenditure (REE) a decrease in physical activity and increased movement economy. ObjectiveTo determine if energy restriction induced adaptive thermogenesis and adaptations in physical activity are related to changes in leptin concentrations. MethodsEighty-two healthy subjects (23 men, 59 women), mean±SD age 41±8years and BMI 31.9±3.0kg/m2, followed a very low energy diet for 8weeks with measurements before and after the diet. Leptin concentrations were determined from fasting blood plasma. Body composition was assessed with a three-compartment model based on body weight, total body water (deuterium dilution) and body volume (BodPod). REE was measured (REEm) with a ventilated hood and predicted (REEp) from measured body composition. Adaptive thermogenesis was calculated as REEm/REEp. Parameters for the amount of physical activity were total energy expenditure expressed as a multiple of REEm (PAL), activity-induced energy expenditure divided by body weight (AEE/kg) and activity counts measured by a tri-axial accelerometer. Movement economy was calculated as AEE/kg (MJ/kg/d) divided by activity counts (Mcounts/d). ResultsSubjects lost on average 10.7±4.1% body weight (P<0.001). Leptin decreased from 26.9±14.3 before to 13.9±11.3μg/l after the diet (P<0.001). REEm/REEp after the diet (0.963±0.08) was related to changes in leptin levels (R2=0.06; P<0.05). There was no significant correlation between changes in leptin concentrations and changes in amount of physical activity. Movement economy changed from 0.036±0.011J/kg/count to 0.028±0.010J/kg/count and was correlated to the changes in leptin concentrations (R2=0.07; P<0.05). ConclusionDuring energy restriction, the decrease in leptin explains part of the variation in adaptive thermogenesis. Changes in leptin are not related to the amount of physical activity but could partly explain the increased movement economy.

Evaluation of a new impedancemeter to independently measure extracellular, intracellular and total body water volumes: application to the measurement of hydration.

The objective of this study was to evaluate the accuracy of independent hydric data for the quantification of total body water (V t), extracellular water (V e) and intracellular water (V i), obtained by a multifrequency impedancemeter Z-Métrix(®) (ZM), in standing and lying position, with respect to the Xitron reference. In a second step, the aim was to consider whether it is possible to quantify daily hydration. The average repeatability error of the ZM impedancemeter is less than 0.5%. For total body water (V t), we note a low R (2) dispersion with an average of 0.9 for men and 0.6 for women. The estimation of extracellular water is equivalent to a maximum error of 3.1% in standing position for women against 2.97% for men in the same position. The estimation of the total body water by direct measurement and by summing the volumes of extracellular and intracellular water obtained by the Z-Metrix(®) shows very low dispersions with R (2)=0.89 and average error from 1.3% for healthy women in lying position to 3.9% for healthy women in standing position. Finally, despite the impact of events on the daily measurements, it is viable to track a subject's overall hydration.

Body mass index as discriminator of the lean mass deficit and excess body fat in institutionalized elderly people

The objective of this study was to identify the discriminating criterion for body mass index (BMI) in the prediction of low fat free mass and high body fat percentage according to sex among older people. Observational analytical study with cross-sectional design was used for this study. All institutionalized older people from the city of Uberaba (Minas Gerais, Brazil) who fit within the inclusion and exclusion criteria were approached. Sixty-five institutionalized older people were evaluated after signing a Free and Informed Consent Form. Descriptive and inferential statistical procedures were employed for the analysis, using Student's t-test and multiple linear regression. Receiver Operating Characteristic (ROC) curves were constructed to determine the BMI (kg/m2) cut-off points. The study complied with all the ethical norms for research involving human beings. In comparing the anthropometric measurements obtained via bioimpedance, elder male had higher mean height and body water volume than females. However, women had higher mean triceps skinfold and fat free mass than men. The BMI cut-off points, as discriminators of low fat free mass percentage and high body fat percentage in women, were ≤22.4 kg/m2 and >26.6 kg/m2, respectively; while for men they were ≤19.2 kg/m2 and >23.8 kg/m2. The results of this study indicate the need for multicenter studies aimed at suggesting BMI cut-off points for institutionalized older people, taking into account specific sex characteristics.

Japanese society for dialysis therapy clinical guideline for "hemodialysis initiation for maintenance hemodialysis".

Yuzo Watanabe, Kunihiro Yamagata, Shinichi Nishi, Hideki Hirakata, Norio Hanafusa, Chie Saito, Motoshi Hattori, Noritomo Itami, Yasuhiro Komatsu, Yoshindo Kawaguchi, Kazuhiko Tsuruya, Yoshiharu Tsubakihara, Kazuyuki Suzuki, Ken Sakai, Hideki Kawanishi, Daijo Inaguma, Hiroyasu Yamamoto, Yoshiaki Takemoto, Noriko Mori, Kazuyoshi Okada, Hiroshi Hataya, Takashi Akiba, Kunitoshi Iseki, Tadashi Tomo, Ikuto Masakane, Tadao Akizawa, and Jun Minakuchi, for “Hemodialysis Initiation for Maintenance Hemodialysis” Guideline Working Group, Japanese Society for Dialysis Therapy

PPARγ Agonist-Induced Fluid Retention Depends on αENaC Expression in Connecting Tubules

Background/Aims: Thiazolidinediones (TZDs, like rosiglitazone (RGZ)) are peroxisome proliferator-activated receptor γ (PPARγ) agonists used to treat type 2 diabetes. Clinical limitations include TZD-induced fluid retention and body weight (BW) increase, which are inhibited by amiloride, an epithelial-sodium channel (ENaC) blocker. RGZ-induced fluid retention is maintained in mice with αENaC knockdown in the collecting duct (CD). Since ENaC in the connecting tubule (CNT) rather than in CD appears to be critical for normal NaCl retention, we aimed to further explore the role of ENaC in CNT in RGZ-induced fluid retention. Methods: Mice with conditional inactivation of αENaC in both CNT and CD were used (αENaC lox/lox AQP2-Cre; ‘αENaC-CNT/CD-KO') and compared with littermate controls (αENaC lox/lox mice; ‘WT'). BW was monitored and total body water (TBW) and extracellular fluid volume (ECF) were determined by bioelectrical impedance spectroscopy (BIS) before and after RGZ (320 mg/kg diet for 10 days). Results: On regular NaCl diet, αENaC-CNT/CD-KO had normal BW, TBW, ECF, hematocrit, and plasma Na⁺, K⁺, and creatinine, associated with an increase in plasma aldosterone compared with WT. Challenging αENaC-CNT/CD-KO with a low NaCl diet unmasked impaired NaCl and K homeostasis, consistent with effective knockdown of αENaC. In WT, RGZ increased BW (+6.1%), TBW (+8.4%) and ECF (+10%), consistent with fluid retention. These changes were significantly attenuated in αENaC-CNT/CD-KO (+3.4, 1.3, and 4.3%). Conclusion: Together with the previous studies, the current results are consistent with a role of αENaC in CNT in RGZ-induced fluid retention, which dovetails with the physiological relevance of ENaC in this segment.

Ultrafiltration biofeedback guided by blood volume monitoring to reduce intradialytic hypotensive episodes in hemodialysis: study protocol for a randomized controlled trial.

BackgroundFluid removal during dialysis, also known as ultrafiltration (UF), leads to intradialytic hypotension (IDH) in a significant number of patients treated with hemodialysis (HD) and is associated with an increase in morbidity and mortality. At present, there are no accepted standards of practice for the prevention or treatment of IDH. Relative blood volume monitoring (BVM) is based on the concept that the hematocrit increases with UF, relative to the patient’s baseline hematocrit. The use of BVM biofeedback, whereby the HD machine automatically adjusts the rate of UF based on the relative blood volume, has been proposed for the prevention of IDH.Methods/DesignThis is a 22-week randomized crossover trial. Participants undergo a 4-week run-in phase to standardize medications and dialysis prescriptions. Subsequently, participants are randomized to standard HD or to BVM biofeedback for a period of 8 weeks followed by a 2-week washout phase before crossing over. The dialysis prescription remains identical for both arms. The primary outcome is the frequency of symptomatic IDH as defined by an abrupt drop in the systolic blood pressure of ≥20 mm Hg accompanied by headache, dizziness, loss of consciousness, thirst, dyspnea, angina, muscle cramps or vomiting. Secondary outcomes include the number of symptomatic IDH episodes and any reduction in IDH episodes, nursing interventions, dialysis adequacy, total body water, extra- and intracellular fluid volumes, brain natriuretic peptide and cardiac troponin levels, blood pressure, antihypertensive medication use, patient symptoms and quality of life.DiscussionOur study will determine the impact of using BVM biofeedback to prevent IDH and other serious adverse events in susceptible patients.Trial registrationClinicaltrials.gov NCT01988181 (6 November 2013).Electronic supplementary materialThe online version of this article (doi:10.1186/1745-6215-15-483) contains supplementary material, which is available to authorized users.

Are we being drowned in hydration advice? Thirsty for more?

Hydration pertains simplistically to body water volume. Functionally, however, hydration is one aspect of fluid regulation that is far more complex, as it involves the homeostatic regulation of total body fluid volume, composition and distribution. Deliberate or pathological alteration of these regulated factors can be disabling or fatal, whereas they are impacted by exercise and by all environmental stressors (e.g. heat, immersion, gravity) both acutely and chronically. For example, dehydration during exercising and environmental heat stress reduces water volume more than electrolyte content, causing hyperosmotic hypohydration. If exercise continues for many hours with access to food and water, composition returns to normal but extracellular volume increases well above baseline (if exercising upright and at low altitude). Repeating bouts of exercise or heat stress does likewise. Dehydration due to physical activity or environmental heat is a routine fluid-regulatory stress. How to gauge such dehydration and — more importantly—what to do about it, are contested heavily within sports medicine and nutrition. Drinking to limit changes in body mass is commonly advocated (to maintain ≤2% reduction), rather than relying on behavioural cues (mainly thirst) because the latter has been deemed too insensitive. This review, as part of the series on moving in extreme environments, critiques the validity, problems and merits of externally versus autonomously controlled fluid-regulatory behaviours, both acutely and chronically. Our contention is that externally advocated hydration policies (especially based on change in body mass with exercise in healthy individuals) have limited merit and are extrapolated and imposed too widely upon society, at the expense of autonomy. More research is warranted to examine whether ad libitum versus avid drinking is beneficial, detrimental or neither in: acute settings; adapting for obligatory dehydration (e.g. elite endurance competition in the heat), and; development of chronic diseases that are associated with an extreme lack of environmental stress.

The interrelationship of research in the laboratory and the field to assess hydration status and determine mechanisms involved in water regulation during physical activity.

Changes in skin blood and sweating are the primary mechanisms for heat loss in humans. A hot, humid environment concomitant with dehydration limits the ability to increase skin blood flow for the purpose of transferring heat from the body core to skin surface and evaporate sweat to maintain core temperature within safe limits during exercise. Adequate hydration improves thermoregulation by maintaining blood volume to support skin blood flow and sweating. Humans rely on fluid intake to maintain total body water and blood volume, and have developed complex mechanisms to sense changes in the amount and composition of fluid in the body. This paper addresses the interrelationship of research in the laboratory and the field to assess hydration status involved in body water and temperature regulation during exercise. In the controlled setting of a research laboratory, investigators are able to investigate the contributions of volume and tonicity of fluid in the plasma to body water and temperature regulation during exercise and recovery. For example, laboratory studies have shown that tonicity in a rehydration beverage maintains the thirst mechanism (and stimulates drinking), and contributes to the ongoing stimulation of renal fluid retention hormones, ultimately leading to a more complete rehydration. Research in the field cannot control the environment precisely, but these studies provide a natural, ‘real-life’ setting to study fluid and temperature regulation during exercise. The conditions encountered in the field are closest to the environment during competition, and data collected in the field can have an immediate impact on performance and safety during exercise. There is an important synergy between these two methods of collecting data that support performance and protect athletes from harm during training and improve performance during competition.

Monitoring of body water composition by the simultaneous use of bioelectrical impedance analysis and Crit-Line® during hemodialysis

Bioelectrical impedance analysis (BIA) is a non-invasive method to estimate total body water (TBW) and extracellular water (ECW) volume. Crit-Line(®) (CL), on the other hand, assesses intravascular water (IVW) volume. We evaluate continuous changes in body water composition during hemodialysis (HD) with concurrent use of BIA and CL. BIA at the start and the end of the HD session was measured using a BIA device. To investigate the shifting pattern of body water composition, patients were subjected to simultaneous monitoring of BIA with CL. Both TBW resistance (Rt) and ECW resistance (Re) increased in response to changes in the ultrafiltration (UF) ratio. There was a positive correlation between ΔRe/Rt and the UF ratio, and the ratio of Re/Rt at the end of HD was significantly higher than that at the start of HD. Simultaneous monitoring of BIA with CL showed a parallel shift of the change in the Re (ΔRe) and the change in hematocrit (ΔHt). In one patient with increasing inflammatory response, change in ΔHt was dissociated from change in ΔRe. One hyponatremic patient showed a different pattern of changing ΔRe between the first half and the latter half of the HD session. Our study suggests that the concurrent use of BIA and CL may be a useful technique to simulate water shift patterns across the different compartments in HD.

Whole-body fluid distribution in humans during dehydration and recovery, before and after humid-heat acclimation induced using controlled hyperthermia

This experiment was designed to test the hypothesis that the plasma volume is not selectively defended during exercise- and heat-induced dehydration following humid-heat acclimation. Eight physically active males were heat acclimated (39.8 °C, relative humidity 59.2%) using 17 days of controlled hyperthermia (core temperature: 38.5 °C). Inter-compartmental fluid losses and movements were tracked (radioisotopes and Evans blue dye) during progressive dehydration (cycling) in these same conditions and also during a resting recovery without fluid replacement (28 °C), before (day 1), during (day 8) and after heat acclimation (day 22). On days 8 and 22, there were significant increases in total body water, interstitial fluid and plasma volume (P < 0.05), but the intracellular compartments did not change (P > 0.05). The baseline plasma volume remained expanded throughout: 43.4 [±2.6 (day 1)], 49.1 [±2.4 (day 8); P < 0.05] and 48.9 mL kg(-1) [±3.0 (day 22); P < 0.05]. During progressive dehydration, plasma reductions of 9.0% (±0.9: day 1), 12.4% (±1.6: day 8) and 13.6% (±1.2: day 22) were observed, with day 8 and 22 losses significantly exceeding day 1 (P < 0.05). During recovery, plasma volume restoration commenced, with the intracellular fluid contribution becoming more pronounced as acclimation progressed. It is concluded that the plasma volume was not defended more vigorously following humid-heat acclimation. Indeed, a greater fluid loss may well underlie the mechanisms for enhancing plasma volume recovery when heat acclimation is induced using the controlled-hyperthermia technique.

Effect of Dialysate Sodium Reduction on Body Water Volume, Blood Pressure, and Inflammatory Markers in Hemodialysis Patients — A Prospective Randomized Controlled Study

Accumulating evidence suggests an association between body volume overload and inflammation in chronic kidney diseases. The purpose of this study was to evaluate the effect of dialysate sodium concentration reduction on extracellular water volume, blood pressure (BP), and inflammatory state in hemodialysis (HD) patients. In this prospective controlled study, adult patients on HD for at least 90 days and those with C-reactive protein (CRP) levels ≥ 0.7 mg/dL were randomly allocated into two groups: group A, which included 29 patients treated with reduction of dialysate sodium concentration from 138 to 135 mEq/L; and group B, which included 23 HD patients not receiving dialysate sodium reduction (controls). Of these, 20 patients in group A and 18 in group B completed the protocol study. Inflammatory, biochemical, hematological, and nutritional markers were assessed at baseline and after 8 and 16 weeks. Baseline characteristics were not significantly different between the two groups. Group A showed a significant reduction in serum concentrations of tumor necrosis factor-α, and interleukin-6 over the study period, while the BP and extracellular water (ECW) did not change. In Group B, there were no changes in serum concentrations of inflammatory markers, BP, and ECW. Dialysate sodium reduction is associated with attenuation of the inflammatory state, without changes in the BP and ECW, suggesting inhibition of a salt-induced inflammatory response.

Rapid Weight Loss and the Body Fluid Balance and Hemoglobin Mass of Elite Amateur Boxers

Dehydration is assumed to be a major adverse effect associated with rapid loss of body mass for competing in a lower weight class in combat sports. However, the effects of such weight cutting on body fluid balance in a real-life setting are unknown. To examine the effects of 5% or greater loss of body mass within a few days before competition on body water, blood volume, and plasma volume in elite amateur boxers. Case-control study. Sports medicine laboratory. Seventeen male boxers (age = 19.2 ± 2.9 years, height = 175.1 ± 7.0 cm, mass = 65.6 ± 9.2 kg) were assigned to the weight-loss group (WLG; n = 10) or the control group (CON; n = 7). The WLG reduced body mass by restricting fluid and food and inducing excessive sweat loss by adhering to individual methods. The CON participated in their usual precompetition training. During an ordinary training period (t-1), 2 days before competition (t-2), and 1 week after competition (t-3), we performed bioelectrical impedance measurements; calculated total body water, intracellular water, and extracellular water; and estimated total hemoglobin mass (tHbmass), blood volume, and plasma volume by the CO-rebreathing method. In the WLG, the loss of body mass (5.6% ± 1.7%) led to decreases in total body water (6.0% ± 0.9%), extracellular water (12.4% ± 7.6%), tHbmass (5.3% ± 3.8%), blood volume (7.6% ± 2.1%; P < .001), and plasma volume (8.6% ± 3.9%). The intracellular water did not change (P > .05). At t-3, total body water, extracellular water, and plasma volume had returned to near baseline values, but tHbmass and blood volume still were less than baseline values (P < .05). In CON, we found no changes (P > .05). In a real-life setting, the loss of approximately 6% body mass within 5 days induced hypohydration, which became evident by the decreases in body water and plasma volume. The reduction in tHbmass was a surprising observation that needs further investigation.

Prediction of body water compartments in preterm infants by bioelectrical impedance spectroscopy

To evaluate nutritional interventions in preterm infants, a simple, accurate assessment of the type of growth, that is, change in body composition through the relative contributions of lean body tissue and fat mass to weight gain, is needed. Bioelectrical impedance may provide such a method. The aim of this study was to develop resistivity coefficients appropriate for use in bioelectrical impedance spectroscopy (BIS) analysis of body water volumes in preterm infants. A total of 99 preterm infants were enrolled (mean gestational age 32 completed weeks). Total body water (TBW) and extracellular water (ECW) were determined using the reference methods of deuterium and bromide dilution. BIS measurements taken at the same time allowed calculation of resistivity coefficients. Predictions of TBW and ECW obtained using these coefficients were then validated against volumes determined using the reference methods in a separate cohort of infants. Data were available for 91 preterm infants. BIS-predicted TBW and ECW correlated well with the measured volumes (Pearson's r(p)=0.825 and 0.75, respectively). There was a small bias (TBW 10 ml and ECW 40 ml) but large limits of agreement (TBW ± 650 ml and ECW ± 360 ml). BIS appears to have limited clinical utility; however, the relatively small bias means that it may be useful for measurements within a population or for comparisons between groups in which population means rather than individual values are compared.

Maternal Nutritional Status in Early Pregnancy Is Associated with Body Water and Plasma Volume Changes in a Pregnancy Cohort in Rural Bangladesh ,

Plasma volume expansion has been associated with fetal growth. Our objective was to examine the associations between maternal nutritional status in early pregnancy and extracellular water (ECW), total body water (TBW), and percentage plasma volume change across pregnancy. In a subsample of 377 pregnant women participating in a cluster-randomized trial of micronutrient supplementation, hemoglobin, hematocrit, and multi-frequency bioelectrical impedance were measured at ~10, 20, and 32 wk of gestation. In early pregnancy, women were short (mean ± SD, 148.9 ± 5.3 cm) and thin (19.5 ± 2.5 kg/m2). In mixed-effects multiple regression models, a 1-unit higher BMI at ~10 wk was associated with higher ECW and TBW (0.27 and 0.66 kg per kg/m2, respectively;P< 0.01) at ~10, ~20, and ~32 wk. Height was also positively associated with ECW and TBW at each time point. Early pregnancy BMI was negatively associated with gains in ECW and TBW (-0.06 and -0.14 kg per kg/m2, respectively;P< 0.01) from 10 to 20 wk, but not with 20- to 32-wk gains after accounting for weight gain. BMI was positively associated with percentage changes in plasma volume from 20 to 32 wk (0.57% per kg/m2;P< 0.05). Height was not associated with changes in body water or plasma volume. Women with low BMI and height in early pregnancy have lower ECW and TBW in early, mid, and late pregnancy and lower late pregnancy plasma volume expansion, potentially increasing risk of fetal growth restriction.

Assessing Water-Electrolyte Changes of Hyperglycaemic Hyperosmolar Coma

We reported new methods to accurately estimate salt and water deficits during hyperglycaemic hyperosmolar coma (HC), valid under restricted boundary conditions. The accuracy of these estimates is herein verified over the unrestricted spectrum of abnormalities, to correctly evaluate any patient with just one algorithm that recognizes the boundary conditions pertaining to each abnormality, choosing the appropriate calculations. A large number of cases of HC was simulated on computer by subtracting an exhaustive combination of water, sodium and chloride losses coupled to a large variety of gains in glucose. Altered solute concentrations were generated. From these true plasma concentrations generated by the computer, the losses of water and electrolytes were back-calculated with our new computational algorithm, by knowing in addition only the normal total body water and extra-cellular volume. The accuracy of the method was tested by comparing true to calculated values over the entire range of deranged values. In 100 patients admitted to hospital for HC these same computations were performed, where calculated data were validated by comparing them to true data obtained by balance studies performed during correction of the abnormality. Both in simulated and real cases of HC true and calculated data for the changes in Na and volume were significantly correlated (R (2)=0.76 and 0.50, respectively, P<0.01), while their mean values were not significantly different by paired "t" tests (P>0.05 for all). Our new computation algorithm, applicable to the bed-side, useful in accurately assessing the average water-electrolyte deficits of HC, can be used to guide correct re-infusion strategies.

Parameter Identification for a New Circuit Model Aimed to Predict Body Water Volume

Intracellular and extracellular water volumes in the human body have been computed using a sequence of models starting with a linear first order RC circuit (Cole model) and finishing w ...

Scientific Basis of Hyponatremia and Its Clinical Presentations

Purpose To describe causes, pathophysiologic mechanisms, and classifications of hyponatremia, and to describe clinical symptoms and underlying disease states associated with different levels of hyponatremia. Summary The key to comprehending hyponatremia is to understand body water content and plasma osmolality and accurately assess arterial volume. Hyponatremia results from sodium dilution because of retained water or sodium depletion because of electrolyte loss in excess of water loss. Body sodium, water, and extracellular fluid (ECF) volume are tightly regulated by mechanisms that act to maintain a closely controlled concentration of solutes in the ECF. These forces act to regulate water content and sodium excretion to maintain normal intravascular volume. The body closely defends normal plasma osmolality within a narrow range primarily by controlling the release of arginine vasopressin (AVP) and via the thirst mechanism. A number of factors can stimulate inappropriate AVP release and cause or worsen hyponatremia. Dysregulation of AVP plays an important role in heart failure and cirrhosis, common causes of hypervolemic hyponatremia. Conclusion Body water content and plasma osmolality are tightly regulated by the action of AVP. A variety of disease states are associated with hyponatremia related to inappropriate AVP release. The cause of the electrolyte disturbance must be determined, because it can have profound implications for treatment. Differential diagnosis can be guided by observation of the rapidity of onset as well as volume status changes. If untreated or treated inappropriately, hyponatremia can impact morbidity and mortality.