Showing papers on "Body water published in 2002"

Bioelectrical Impedance to Estimate Changes in Hydration Status

Abstract: Bioelectrical impedance analysis (BIA) has been suggested as a simple, rapid method to assess changes in hydration status. BIA measures the electrical impedance to a low amperage current that is affected by both water and electrolyte content of the body. While BIA can reliably estimate total body water and body density in euhydrated individuals under standardized clinical conditions, changes in fluid and electrolyte content can independently alter bioimpedance measurements. Because hydration changes typically involve concomitant changes in fluid and electrolyte content, the interpretation of a change in bioimpedance will often be confounded. This paper examines the assumptions underlying estimations of total body water from BIA and addresses the factors known to influence bioimpedance independently from actual change in total body water. The results indicate that current BIA methodology may not provide valid estimates of total body water when hydration state is altered.

Dietary protein adequacy and lower body versus whole body resistive training in older humans

Abstract: This study assessed the effects of long-term consumption of the United States Recommended Dietary Allowance (RDA) for protein by older people who were sedentary or performed resistive training (RT) on body composition, skeletal muscle size and protein metabolism, and if the number of muscle groups trained influenced the muscle hypertrophy response to RT. Twelve men and 17 women (age range 54-78 years) completed this 14 week controlled diet and exercise study. Throughout the study, each subject completely consumed daily euenergetic menus that provided the RDA of 0.8 g protein kg(-1) day(-1). From study weeks 3-14 (weeks RT1-RT12), 10 subjects (four men, six women) performed whole body RT (WBRT), nine subjects (four men, five women) performed lower body RT (LBRT) and 10 subjects (four men, six women) remained sedentary (SED). Both the LBRT and WBRT groups performed knee extension and flexion exercises, and the WBRT group also performed chest press and arm pull exercises (three sets per exercise at 80 % of one repetition maximum, 3 days per week for 12 weeks). From week 2 (baseline) to week RT12, muscle strength increased in muscle groups trained in the LBRT and WBRT groups, and was not changed in the SED group. From baseline to week RT12, whole body muscle mass and protein-mineral mass were not changed, fat-free mass (P = 0.004) and total body water (P = 0.013) were decreased, and percentage body fat was increased (P = 0.011) in these weight-stable older people, independent of group assignment. The RT-induced increases in mid-thigh muscle area (from computed tomography scans) were comparable in the LBRT and WBRT groups (2.13 +/- 1.26 cm(2) and 2.17 +/- 1.24 cm(2), respectively), and were different from those in the SED group, which lost muscle area (-1.74 +/- 0.57 cm(2); group-by-time P < 0.05). From baseline to week RT12, 24 h urinary total nitrogen excretion decreased (P < 0.001), nitrogen balance shifted from near equilibrium to positive, whole body leucine oxidation (from the infusion of L-[(13)C]leucine) decreased (P < 0.05) and net (postabsorptive vs. postprandial) leucine balance (P < 0.05) increased from near equilibrium to positive, with no differences in responses over time among the three groups. In conclusion, the number of muscle groups trained did not influence whole body protein metabolism or RT-induced muscle hypertrophy in older people. Most of these data are consistent with a successful adaptation to the RDA for protein. However, research should continue to question whether the decreases in fat-free mass and total body water observed in all subjects, and the decrease in mid-thigh muscle area in the SED group, are physiological accommodations, and whether the RDA for protein might be marginally inadequate for older people to maintain skeletal muscle.

Relationships between body composition parameters and fluorouracil pharmacokinetics

Abstract: Aims To verify whether fluorouracil (FU) clearance (CL) and volume of distribution (Vss) are better correlated with specific body compartments, such as body cell mass (BCM), total body water (TBW) or fat free mass (FFM), rather than with body surface area (BSA) or total body weight (BW). Methods Thirty-four patients (13 females and 21 males) affected by colorectal cancer and receiving FU as adjuvant therapy entered the study. CL and Vss were determined after a 2 min i.v. injection of FU (425 mg m−2) and leucovorin (20 mg m−2). Body composition, in terms of BCM, TBW and FFM, was evaluated non-invasively by bioelectrical impedance analysis (BIA). Results Significant but poor correlations were found between CL or Vss and most anthropometric parameters, including BIA-derived measures (r2 range=0.10–0.21). However, when multiple regression analysis was performed with sex, TBW and FFM as independent variables, the correlations improved greatly. The best correlation was obtained between CL and sex (r2=0.44) and between Vss and sex (r2=0.36). FFM-normalized CL was significantly higher in women than in men (0.030±0.008 vs 0.022±0.005 l min−1 kg−1; 95% CI of difference 0.012, 0.003; P=0.003), suggesting that FU metabolism is more rapid in females. Surprisingly, Vss was highly correlated with CL (r2=0.67; CL=0.52+Vss×0.040). This finding may either be explained by extensive drug metabolism in extra-hepatic organs or by variable inactivation on first-pass through the lung. Both these hypotheses need experimental validation. Conclusions The pharmacokinetics of FU are better predicted by FFM and TBW than by standard anthropometric parameters and predictions are sex-dependent. The use of BIA may lead to improved dosing with FU.

Validity of total and segmental impedance measurements for prediction of body composition across ethnic population groups

Abstract: Objectives: To test the impact of body build factors on the validity of impedance-based body composition predictions across (ethnic) population groups and to study the suitability of segmental impedance measurements. Design: Cross-sectional observational study. Settings: Ministry of Health and School of Physical Education, Nanyang Technological University, Singapore. Subjects: A total of 291 female and male Chinese, Malays and Indian Singaporeans, aged 18–69, body mass index (BMI) 16.0–40.2 kg/ m2. Methods: Anthropometric parameters were measured in addition to impedance (100 kHz) of the total body, arms and legs. Impedance indexes were calculated as height2/impedance. Arm length (span) and leg length (sitting height), wrist and knee width were measured from which body build indices were calculated. Total body water (TBW) was measured using deuterium oxide dilution. Extra cellular water (ECW) was measured using bromide dilution. Body fat percentage was determined using a chemical four-compartment model. Results: The bias of TBW predicted from total body impedance index (bias: measured minus predicted TBW) was different among the three ethnic groups, TBW being significantly underestimated in Indians compared to Chinese and Malays. This bias was found to be dependent on body water distribution (ECW/TBW) and parameters of body build, mainly relative (to height) arm length. After correcting for differences in body water distribution and body build parameters the differences in bias across the ethnic groups disappeared. The impedance index using total body impedance was better correlated with TBW than the impedance index of arm or leg impedance, even after corrections for body build parameters. Conclusions: The study shows that ethnic-specific bias of impedance-based prediction formulas for body composition is due mainly to differences in body build among the ethnic groups. This means that the use of ‘general’ prediction equations across different (ethnic) population groups without prior testing of their validity should be avoided. Total body impedance has higher predictive value than segmental impedance.

Segmental bioelectrical impedance analysis in children aged 8-12 y: 1. The assessment of whole-body composition.

Abstract: Objectives: To investigate the potential of segmental bioelectrical impedance analysis (BIA) for estimating whole-body composition in children. Design: Strengths of relationships were determined between indices of impedance or specific resistivities of body segments and reference four-component model (4-CM) assessments of body composition. Subjects: Eighteen boys and 19 girls aged 8–12 y. Measurements: Whole-body and segment BIA and anthropometry were used to calculate impedance indices of the whole body and segments and specific resistivities of segments; total body water (TBW), fat-free mass (FFM) and body fat were assessed using the 4-CM. Results: Segmental BIA indices were significantly related to body composition, provided that appropriate comparisons were undertaken for each index: impedance adjusted for unit segment length was better related to TBW and FFM, whereas segment specific resistivity was better related to body fat. Differences between body composition estimates obtained with the 4-CM and predicted using BIA were partly dependent on limb-to-trunk ratios of BIA indices. Conclusion: Segmental BIA has potential for providing additional alternative approaches to the assessment of whole-body composition in children: (a) FFM and TBW were best related to impedance adjusted for segment length; (b) body fat was best related to segment specific resistivity; and (c) the relative influences of different segment BIA indices may be utilisable for generating more valid whole-body composition estimates.

Accuracy of bioelectrical impedance spectroscopy in measuring changes in body composition during severe weight loss.

Abstract: BACKGROUND: Bioelectrical impedance spectroscopy (BIS) is an attractive method for measuring body composition because it is noninvasive, simple, and cheap. The effect of obesity on the accuracy of impedance measurements has been recognized for some time, but no conclusive explanations or ways to correct the measurement errors have been published. We studied the effect of the composition of weight loss on the accuracy of BIS to measure changes in body fluid volumes during severe weight loss. Within subjects the effect of variable losses of fat mass was studied. METHODS: In 10 morbidly obese female subjects who underwent gastric reduction surgery, changes in total body water (TBW) and extracellular water (ECW) were monitored for 1 year by deuterium (Deu) and bromide (Br) dilution and by BIS. Measurements were performed before the operation and after 2 weeks, 3 months, and 1 year. Extrapolated resistance values of extracellular (Recw) and intracellular water (Ricw) were used in mixture equations for calculat...

Central, peripheral, and other blood volume changes during hemodialysis.

Abstract: Volume overload is a factor in development of hypertension in hemodialysis patients. Fluid removal by hemodialysis (HD), however, may cause intradialytic hypotension and associated symptoms. A better understanding of the relationships between blood pressure volume status and the pathophysiology of fluid removal during HD are, therefore, necessary to control blood pressure and to eliminate intradialytic hypotension. The objectives of the study were to determine the amount and direction of change of body fluid compartments after ultrafiltration (UF) and to determine whether any correlations exist between mean arterial pressure (MAP), change in circulating blood volume (deltaBV), total body water (TBW), central blood volume (which constitutes the volume of blood in the lungs, heart, and great vessels [CBV]), and intracellular and extracellular fluid volumes (ICF, ECF). The study population included 20 patients on regular HD. Each individual had their CBV, cardiac output, and peripheral vascular resistance (PVR) measured by means of saline dilution technique and deltaBV monitored by an online hematocrit sensor (Crit Line). MAP was calculated from measured blood pressure and ICF and ECF were measured using bioelectric impedance analysis techniques. Measurements were obtained before and after maximum UF measured by deltaBV (reduction of 6-10% by Crit Line). Ten healthy controls also had ECF and ICF values measured by bioelectric impedance analysis. Before HD, MAP correlated with TBW (r = 0.473, p = 0.035) and CBV (r = 0.419, p = 0.066), suggesting that hypertension here may be due to volume overload. Patients were ECF expanded before HD with an ECF:ICF ratio of 0.96, which was significantly higher than the control ratio of 0.74 (p < 0.0001). During UF, fluid was removed from both ECF and ICF, but more from the ECF volume ratio 0.92 post UF, a significant reduction (p < 0.0001). After UF, MAP no longer correlated with TBW or CBV but correlated with peripheral vascular resistance (r = 0.4575, p = 0.043). After UF, deltaBV correlated inversely with PVR (r = -0.50, p = 0.024). Despite the fall in deltaBV (7.11+/-2.49%) with UF, CBV was maintained. CBV were 0.899 L and 0.967 L pre and post UF, respectively. These data suggest that in hemodialysis patients, predialysis volume status influences predialysis blood pressure. UF causes BV to fall, but CBV is preferentially conserved by increasing PVR, which also maintains blood pressure. Failure of a PVR response likely leads to intradialytic hypotension.

Measuring the nutritional status of children with juvenile idiopathic arthritis using the bioelectrical impedance method

Abstract: Objective. To assess the nutritional status of children with juvenile idiopathic arthritis (JIA) using anthropometric measurements and bioelectrical impedance. Methods. Twenty-two consecutive JIA patients (seven pauciarticular, 15 polyarticular) attending the rheumatology clinic at Booth Hall Children’s Hospital were compared with 22 age- and sex-matched controls attending the accident and emergency department of the same hospital. There were no patients with systemic-onset JIA in the cohort. Height, weight, head circumference and skinfold thickness at four sites (biceps, triceps, subscapular and suprailiac) were measured. Regression equations were used to calculate body fat as a percentage of weight, and arm muscle circumference. In addition, bioelectrical impedance measurements were made using a Holtain body composition analyser. These measurements were then used to calculate the total body water, which could be used as an indirect estimate of the lean body mass. Results. Of the JIA patients, 22.7% were below the third centile for height, 18.1% had a weight less than the third centile. Mid-arm circumference was below the fifth centile in 36.4% of the patients. Patients with polyarticular disease showed significantly more signs of malnutrition than patients with pauciarticular disease. In the polyarticular group, comparison with controls revealed significant P values for reduction in height (0.047), weight (0.045), mid-arm circumference (0.002), arm muscle circumference (0.012), percentage body fat (0.008) and total body water (0.031). Conclusions. In view of the findings of lower total body water, indicating lower lean mass, in more nutritionally deprived JIA patients (as deduced by the other physical parameters measured), we conclude that bioelectrical impedance is a useful adjunct to anthropometric measures in assessing nutritional status in JIA.

Continuous monitoring of plasma, interstitial, and intracellular fluid volumes in dialyzed patients by bioimpedance and hematocrit measurements.

Abstract: Bioimpedance spectroscopy (BIS) permits evaluation of extra- and intracellular fluid volumes in patients. We wished to examine whether this technique, used in combination with hematocrit measurement, can reliably monitor fluid transfers during dialysis. Ankle to wrist BIS measurements were collected during 21 dialysis runs while hematocrit was continuously monitored in the blood line by an optical device. Extracellular (ECW) and intracellular (ICW) water volumes were calculated using Hanai's electrical model of suspensions. Plasma volume variations were calculated from hematocrit, and changes in interstitial volume were calculated as the difference between ECW and plasma volume changes. Because accuracy of ICW was too low, changes in ICW were calculated as the difference between ultrafiltered volume and ECW changes. Total body water (TBW) volumes calculated pre- and postdialysis were, respectively, 3.25+/-3.2 and 1.95+/-2.5 liters lower on average than TBW given by Watson et al.'s correlation. Average decreases in fluid compartments expressed as percentage of ultrafiltered volume were as follows: plasma, 18%; interstitial, 28%, and ICW, 54%. When the ultrafiltered volume was increased in a patient in successive runs, the relative contributions of ICW and interstitial fluid were augmented so as to reduce the relative drop in plasma volume.

Body composition in adults with Type 1 diabetes at onset and during the first year of insulin therapy.

Abstract: Aims To describe body composition in patients with Type 1 diabetes at diagnosis and during the first year after initiation of insulin therapy Research design and methods In 10 (eight male and two female) newly onset Type 1 patients, age 315 ± 32 years (27–37 years) (sd and range), body mass index (BMI) 208 ± 16 (192–234) kg/m2, body composition was estimated by means of dual-energy X-ray absorptiometry (DXA) whole body scanning supplemented by estimation of total body water (TBW) (isotope dilution technique with 3H2O) at diagnosis and after 1, 3, 6 and 12 months of insulin therapy Results During the first year after onset of diabetes body weight (BW) increased 43 ± 29 (01–83) kg (P = 00012) distributed as a 133% (16 kg) increase in total fat mass (FM) and 49% (25 kg) increase in lean body soft tissue mass (LBM) The self-reported weight loss at onset was 63 ± 25 kg (15–100 kg) Compared with two reference populations the Metropolitan Life Insurance Co and a healthy age and sex-matched local DXA scanned group the initial body composition data demonstrated BW 62 kg below ideal weight and a significant reduction of the FM (25% or –087 sd), whereas LBM was within the expected range Conclusions During the first year after onset of Type 1 diabetes the mean increase in BW is 65% with a 133% increase in FM and a 49% increase in LBM Self-reported data on premorbid BW suggest an approximately 10% reduction in BW at onset of Type 1 diabetes Compared with a healthy reference population initial body composition data demonstrate a 25% reduction of the FM, whereas only a minor and non-significant reduction in the LBM is encountered These data indicate that uncontrolled diabetes is rather a fat catabolic state than, as previously believed, a protein catabolic state

The influence of transient change of total body water on relative body fats based on three bioelectrical impedance analyses methods. Comparison between before and after exercise with sweat loss, and after drinking.

Abstract: Background. The purpose of this study was to clarify the influence of change of total body water caused by exercise and drinking, on relative body fat (%BF) based on three bioelectrical impedance analyses (BIA) methods, between hand and foot (H-F), between hand and hand (H-H), and between foot and foot (F-F). Methods. The subjects were 30 Japanese healthy young adults aged 18 to 23 years (15 males, 15 females). Measurements were made three times for each BIA method; before and after exercise with sweat, and after drinking, and also twice according to the under water weighing (UW) method, before exercise and after drinking. A pedaling exercise, with a bicycle ergometer, was used for 60 minutes as the exercise. Results. The relationship of %BF between the UW method and each BIA method was mid-range or more (r=0.765-0.839). However, %BF based on the H-F and F-F BIA methods were higher than that based on the UW method. After drinking, %BF of all the BIA methods were higher than the UW method. %BF of the BIA methods after exercise indicated values lower than those before exercise. %BF of the H-F and H-H BIA methods after drinking were a little higher than those before exercise, indicating that those measurements reflect a slight change of body water. Conclusions. It was demonstrated that %BF of any BIA method reflect the change of body water caused by exercise, sweating, and drinking.

Evaluation of bioelectrical impedance analysis as an estimator of moose body composition

Abstract: Abstrac tEstimation of body composition of wild ungulates yields important information regardin g nutritional status of individuals and populations; yet, there are few suitable field tech niques that are nondestructive, unbiased, precise, and quick to perform. We tested th e suitability of bioelectrical impedance analysis (BIA) as an estimator of body composition of moose (Alces alce s) for use in the field. A derived BIA variable, impedance volume , was a significant predictor of body fat (mass and percentage) and body water (mass and percentage) when sex was added to models as an indicator variable but explained onl y 48–57% of variation in composition. Best predictive models included impedance vo l ume, sex, body mass, and a body mas s ×sex interaction. Due to difficulty measurin g body mass of moose in the field, we also generated predictive models when body mas s was replaced with a proxy (length × girth 2 ). Predictive equations for body water wer e more precise than were those for body fat. Impedance estimates decreased as the sub ject’s hind leg was straightened, indicating that animal positioning must be standardized to minimize bias. Lack of precision made BIA unsuitable for estimating moose body fa t in the field. BIA was a precise and quick estimator of body water in moose, but its lim i tations make it more suitable for the laboratory than the field .

ORIGINAL COMMUNICATION Body composition in patients with an ileostomy and inflammatory bowel disease: validation of bio-electric impedance spectroscopy (BIS)

Abstract: Objective: To validate bio-electric impedance spectroscopy (BIS) by comparison with other methods for determination of body water compartments in stable subjects with an ileostomy and no or minor small bowel resection for inflammatory bowel disease (IBD). Subjects: Twenty-one subjects were included, age range 36 – 65 y (female=male1⁄412=9), Crohn’s disease (CD), n1⁄4 14, ulcerative colitis (UC), n1⁄46 and indeterminate colitis (IDC), n1⁄41. Methods: Fluid compartments were assessed by the use of three independent methods: BIS, dual-energy X-ray absorptiometry (DXA) and dilution techniques (DIL); tritiated water (total body water, TBW); and bromide (extracellular water, ECW), respectively. Intra-cellular water (ICW) was calculated as TBW7 ECW. For comparison TBW was also predicted according to an empirical formula. Differences were analysed using Bland – Altman plots. Results: The mean TBW values obtained from the impedance measurement differed in the order of 72.21 (DIL) to 1.41 (DXA) in women and 72.01 (DIL) to 2.61 (DXA) in men, from the measured and derived values of total body water. Prediction of TBW gave values that were close to BIS, with a mean difference of 70.31 in male subjects and þ 0.51 in female subjects. Assessment of ECW revealed that the mean difference between dilution and impedance was less in women than in men (P< 0.01). Conclusion: The differences between all methods to assess fluid compartments are pronounced. To further investigate the use of the method in clinical practice for dynamic monitoring of rehydration in ileostomates with acute diarrhoea, repeated measurements together with comparison with weight fluid-balance charts are suggested. Sponsorship: The study was supported by grants from the Swedish Medical Research Council (17X-03117), Goteborgs Lakarsallskap and IB and A Lundbergs forskningsstiftelse. European Journal of Clinical Nutrition (2002) 56, 680 – 686. doi:10.1038=sj.ejcn.1601378

Effect of air temperature and energy intake on body mass, body composition and energy requirements in sheep

Abstract: Body mass was measured and body composition and energy requirements were estimated in sheep at four air temperatures (0 °C to 30 °C) and at four levels of energy offered (4715 to 11785 kJ/day) at a time when the sheep reached a constant body mass. Final body mass was affected mainly by metabolizable energy intake and, to a lesser extent, by air temperature, whereas maintenance requirements were affected mainly by air temperature. Mean energy requirements were similar and lowest at 20 °C and 30 °C (407·5 and 410·5 kJ/kg0·75, respectively) and increased with a decrease in air temperature (528·8 kJ/kg0·75 at 10 °C and 713·3 kJ/kg0·75 at 0 °C). Absolute total body water volume was related positively to metabolizable energy intake and to air temperature. Absolute fat, protein and ash contents were all affected positively by metabolizable energy intake and tended to be related positively to air temperature. In proportion to body mass, total body water volume decreased with an increase in metabolizable energy intake and with an increase in air temperature. Proportionate fat content increased with an increase in metabolizable energy intake and tended to increase with an increase in air temperature. In contrast, proportionate protein content decreased with an increase in metabolizable energy intake and tended to decrease with an increase in air temperature. In all cases, the multiple linear regression using both air temperature and metabolizable energy intake improved the fit over the simple linear regressions of either air temperature or metabolizable energy intake and lowered the standard error of the estimate. The fit was further improved and the standard error of the estimate was further lowered using a polynomial model with both independent variables to fit the data, since there was little change in the measurements between 20 °C and 30 °C, as both air temperatures were most likely within the thermal neutral zone of the sheep. It was concluded that total body energy content, total body water volume, fat and protein content of sheep of the same body mass differed or tended to differ when kept at different air temperatures.

Evaluation of multifrequency bioelectrical impedance analysis for the assessment of extracellular and total body water in healthy cats.

Abstract: Multifrequency bioelectrical impedance analysis (MFBIA) is a promising, noninvasive, rapid, safe, portable, reproducible, electrical method of assessing body composition that has the potential to quantify total body water (TBW), extracellular water (ECW) and intracellular water (ICW), and thereby enable prediction of the fat-free mass (FFM), fat mass (FM) and body cell mass (BCM) (1). To our knowledge, there have not been any reports evaluating the use of MF-BIA in cats. The purpose of this study was to develop the scaling constants and assess the effects of animal position, animal length measurement and electrode configuration on the volume prediction accuracy of the Hydra ECF/ICF Bioimpedance Analyzer (Model 4200; Xitron Technologies, San Diego, CA) compared to TBW estimated by deuterium water (D2O) space and ECW estimated by bromide (Br) space in healthy cats.

Body composition in patients with an ileostomy and inflammatory bowel disease: validation of bio-electric impedance spectroscopy (BIS)

Abstract: Objective: To validate bio-electric impedance spectroscopy (BIS) by comparison with other methods for determination of body water compartments in stable subjects with an ileostomy and no or minor small bowel resection for inflammatory bowel disease (IBD). Subjects: Twenty-one subjects were included, age range 36–65 y (female/male=12/9), Crohn's disease (CD), n=14, ulcerative colitis (UC), n=6 and indeterminate colitis (IDC), n=1. Methods: Fluid compartments were assessed by the use of three independent methods: BIS, dual-energy X-ray absorptiometry (DXA) and dilution techniques (DIL); tritiated water (total body water, TBW); and bromide (extracellular water, ECW), respectively. Intra-cellular water (ICW) was calculated as TBW−ECW. For comparison TBW was also predicted according to an empirical formula. Differences were analysed using Bland–Altman plots. Results: The mean TBW values obtained from the impedance measurement differed in the order of −2.21 (DIL) to 1.41 (DXA) in women and −2.01 (DIL) to 2.61 (DXA) in men, from the measured and derived values of total body water. Prediction of TBW gave values that were close to BIS, with a mean difference of −0.31 in male subjects and +0.51 in female subjects. Assessment of ECW revealed that the mean difference between dilution and impedance was less in women than in men (P<0.01). Conclusion: The differences between all methods to assess fluid compartments are pronounced. To further investigate the use of the method in clinical practice for dynamic monitoring of rehydration in ileostomates with acute diarrhoea, repeated measurements together with comparison with weight fluid-balance charts are suggested. Sponsorship: The study was supported by grants from the Swedish Medical Research Council (17X-03117), Goteborgs Lakarsallskap and IB and A Lundbergs forskningsstiftelse.

Apparatus and method for monitoring body composition by measuring body dielectric constant and body impedance based on digital frequency sampling

Abstract: A method for measuring dielectric constant of body endermic tissues and body impedance based on the method of frequency digital sampling and for evaluating body composition, inputting through the I/O interface of a microprocessor the measured body weight frequency signals, oscillating frequency signals related to dielectric constant of body endermic tissues and body impedance signals corresponding to non-fixed different frequencies, calculating through the software of the microprocessor the body fat content, total body water, ratio between intracellular water and total body water and displaying the body weight, body fat content, total body water and ratio between intracellular water and total body water on the display; a body composition monitor based on above method unit, which comprises weighing sensor and weighing signal processing circuit, and display unit.

Estimation of neonatal body composition: isotope dilution versus total-body electrical conductivity.

Abstract: The objective of the study is to evaluate neonatal body composition determined by the isotope dilution method compared with the total-body electrical conductivity (TOBEC) method. An oral dose of

Hemodialysis (HD) versus peritoneal dialysis (PD): latent overhydration in PD patients?

Abstract: Data on the difference in fluid status between hemodialysis (HD) and peritoneal dialysis (PD) patients are scarce. Bio-electrical impedance analysis (BIA) is able to detect total body water (TBW) and its distribution in intracellular (ICW) and extracellular water (ECW). Echographic determination of the diameter of the inferior caval vein (VCD) provides information about the intravascular space (IVS). Nineteen PD-patients and 20 HD-patients in stable clinical condition were studied. In HD-patients a significant decrease in VCD, mean arterial pressure (MAP), TBW and ECW was noted due to ultrafiltration. Both ratios of VCD to ICW/ECW and of VCD to ECW/TBW decreased. No significant differences were found in these variables between PD-patients and HD-patients before HD. In both patient groups the measured variables pointed towards overhydration and the increased ratios both of VCD to ICW/ECW and VCD to ECW/TBW towards the storage of surplus of fluid in the intravascular space. It can be concluded that both PD-patients and HD-patients before HD have a surplus of fluid in the extracellular compartment, predominantly stored in the intravascular space.

Bone mineral density and body composition in Noonan's syndrome: effects of growth hormone treatment.

Abstract: We assessed bone mineral density (BMD) and body composition in children with Noonan's syndrome (NS) before and during growth hormone (GH) treatment. Sixteen children (12 boys, 4 girls) with NS aged 5.8-14.2 (mean 10.0) years were studied for 2 years. Anthropometry, BMD measurements by radiographic absorptiometry and bioimpedance measurements (Akern-BIA 101/S) were performed at baseline and after 3, 6, 12 and 24 months. Daily GH dosage was 0.05 mg/kg. Trabecular volumetric BMD was normal; cortical BMD was in the lower normal range at baseline and slightly increased over the 2 years. Fat free mass and total body water were below normal at the start and increased significantly over the first 3 months, with a slight increment thereafter. Percentage fat mass decreased over the first 6 months and increased thereafter. These findings are comparable to the data on body composition in short normal children and girls with Turner's syndrome treated with GH.

Preventing and managing dehydration.

Abstract: Sufficient body water and electrolyte homeostasis are essential for healthy physiologic functioning. Nurses are key to preventing, detecting early, and treating fluid and electrolyte imbalances. Dehydration significantly alters both physical and psychological functioning, and older adults are at increased risk. Identifying fluid disorders early can prevent complications and reduce hospital stays. Understanding the mechanisms of fluid homeostasis enables nurses to assess, prevent, and collaborate in managing isotonic, hypertonic, and hypotonic dehydration.

Sequential changes of body composition in patients with enterocutaneous fistula during the 10 days after admission.

Abstract: AIM: To investigate the sequential changes of body composition in the metabolic response that occurred in a group of patients with enterocutaneous fistula after admission to the hospital. METHODS: Sixty-one patients with enterocutaneous fistula admitted to our hospital had measurements of body composition by multiple-frequency bioelectrical impedance analysis after admission and 5, 10 days later. Sequential measurements of plasma constitutive proteins were also made. RESULTS: The body weight, fat-free mass, body mass index, and body cell mass were initially well below the normal range, especially the body mass index and body cell mass. And all the data gradually moved up over the 10-day study period, only a highly significant difference was found in body cell mass. Once the patients received nutrition supplement, ECW began to return to normal range slowly as well as ICW and TBW began to rise up, and ECW/TBW significantly declined to near normal level by day 10 in either male or female patients. There was a reprioritization of plasma constitutive protein synthesis that was obligatory and independent of changes in FFM. CONCLUSION: Serial measurements can quantify the disturbance of body composition in enterocutaneous fistula patients. The early nutritional intervention rapidly ameliorates the abnormal distribution of body water while the state-ofthe-art surgical management prevents the further deterioration in cellular composition.

Nutritional status in peritoneal dialysis. Studies in body composition, lipoprotein metabolism and peritoneal function

Abstract: This thesis is based on clinical studies including virtually all patients treated with peritoneal dialysis in Gothenburg during the 1990s. The patients had a fundamentally altered body composition compared to healthy subjects, characterised by a reduction in body cell mass and body fat already at start of dialysis. During PD treatment. a further decrease in body cell mass was observed. Energy stores tended to normalise during the first years of treatment and remained constant thereafter, or declined subsequently. Extracellular water, calculated from the four-compartment model, was increased when patients started PD treatment and increased further, in parallel to the reduction in body cell mass. These alterations were seen in combination with a normal. or slightly reduced, body weight. Standard methods of assessing nutritional status may therefore not be valid in the dialysis population. Prediction equations to estimate total body water, used in measurements of dialysis adequacy, give erroneous results in PD patients, as shown in a study on our PD population. This may have important clinical consequences, especially in wasted patients. Reduced muscle mass is a marker of protein-energy malnutrition, and therefore simple and reliable methods to measure muscle mass are warranted. When lean body mass was calculated from creatinine generation rate and compared to lean body mass estimated from measurements of total body potassium. the agreement between the two methods was low. Furthermore, when repeated measurements of creatinine generation rate were performed, the variation coefficient was unacceptably high. Thus. creatinine generation rate cannot be recommended as a method to evaluate somatic protein status in PD patients. The lipoprotein metabolic derangements are pronounced in PD patients. in which a further increase in cholesterol and cholesterol-rich apoB-containing lipoproteins are added to the already pre-existing renal dyslipidemia. characterised by increased concentration of triglycerides and triglyceride-rich complex lipoproteins. There are indications that dialytic variables may influence this development. When peritoneal function was assessed by the Peritoneal Dialysis Capacity test at start of dialysis, it was observed that peritoneal function reflected patient characteristics and co-morbidity. Patients with systemic disease had enhanced diffusion capacity compared to patients with primary renal disorders. Furthermore, in patients with more severe co-morbidity. peritoneal protein losses were increased. Finally, elderly patients had ultrafiltration conditions that were different from those of younger patients. Peritoneal function remained essentially stable during medium-long term follow up. Body composition features in dialysis patients are similar to those seen in severe disease in general. Thus, it is difficult to separate the effects of malnutrition from the effects of the underlying disease. Specific standards for nutritional status adapted for patients with renal failure are required.