Role of sodium during formation of edema in children with nephrotic syndrome

Background: The pathogenesis of edema in nephrotic syndrome is not entirely understood. The aim of this study was to contribute to the discussion on edema pathogenesis in nephrotic syndrome by following changes in volume and sodium retention for the course of the disease in children with steroid‐sensitive nephrotic syndrome (SSNS). Methods: Forty‐one children with SSNS were included in the study. The patients were divided into three groups (group I: relapse‐edematous; group II: relapse‐edema free; group III: remission). We investigated the value of the significance and area of sodium retention and vasoactive hormones. In addition, we measured parameters such as inferior vena cava collapsibility index, left atrium diameter, and total body water (TBW) to determine the volume load and cause of edema in children with SSNS. Results: TBW increased in the relapse‐nephrotic syndrome group and the difference was statistically significant among groups (P < 0.001). However, inferior vena cava collapsibility index and left atrium diameter were not different among groups. Fractional sodium excretion was lower in children with relapse nephrotic syndrome (P < 0.05). Conclusion: Although TBW increases in children with SSNS, intravascular volume is normal. In addition, hypoalbuminemia and sodium retention of the proximal tubule cause edema in children with SSNS.     

Human body composition as related to surface area

There is a linear relationship between extracellular fluid and body surface area in man. During growth the body cell mass, fat-free solids, and body fat proportions of body weight increase while the extracellular fluid fraction decreases. Growth stops in men as soon as the body cell mass reaches 22.5 kg/m² body surface area and in women when it reaches 16.9 kg/m². The non-muscle cell mass and the muscle cell mass reach a 1:4 ratio in men whereas in women a 1:3.5 proportion—which is more favorable for pregnancy and lactation—is reached. The body composition of the newborn and the infant have fetal characteristics with a low body fat: surface area ratio and a low non-muscle cell mass: surface area ratio. The basal metabolic rate depends on the amount of non-muscle cell mass present, and the total energy change depends on body cell mass.This has been established by measurements of total body potassium, thiosulfate space, total body sodium, 24 h urine creatinine values and basal metabolic rate.Abbreviations BCM body cell mass (kg) - BF depot fat (kg) - Cr creatinine in urine (g/day) - ECF extracellular fluid (kg) - EFFS extracellular fatfree solids (kg) - H height (cm) - ICF intracellular fluid (kg) - L length (cm) - LBM lean body mass (kg) - n number of cases investigated - MCM muscle cell mass (kg) - nMCM non-muscle cell mass (kg) - SA surface area (m²) - TBK total body potassium (mmol) - TBNa total body sodium (mmol) - TBW total body water (kg) - W body weight (kg) Dedicated to Prof. Dr. H. R. Wiedemann on occasion of his 65th birthday     

Cytokine Response in Children Undergoing Surgery for Congenital Heart Disease

Pediatric cardiac surgery with cardiopulmonary bypass (CPB) induces a complex inflammatory response that may cause multiorgan dysfunction. The objective of this study was to measure postoperative cytokine production and correlate the magnitude of this response with intraoperative variables and postoperative outcomes. Serum samples from 20 children (median age, 15 months) undergoing cardiac surgery with CPB were obtained preoperatively and on postoperative days (POD) 1–3. Serum levels of interleukin (IL)-6, IL-8, and IL-10 increased significantly on POD 1 (p < 0.01) vs pre-op values to 271 ± 68, 44 ± 9, 7.5 ± 0.8 pg/ml, respectively, whereas serum IL-1β, IL-12, and tumor neurosis factor -α were not significantly changed. The serum IL-6 and IL-8 levels correlated positively (p < 0.01) with the degree of postoperative medical intervention as measured by the Therapeutic Interventional Scoring System and indicated a greater need for inotropic support (p = 0.057). A negative correlation (p < 0.01) between IL-6, IL-8, and mixed venous oxygen saturation suggested compromised cardiopulmonary function. Patients with single ventricle anatomy had the highest levels of IL-6 and IL-8 (629 ± 131 and 70 ± 17 pg/ml, respectively), with a mean CPB time of 106 ± 23 minutes. Thus, the proinflammatory response after surgery with CPB was associated with postoperative morbidity with increased need for medical intervention.     

Influence of respiratory distress syndrome on body composition after preterm birth

AIM—To observe changes in body composition during the first week after birth, in preterm neonates with and without respiratory distress syndrome (RDS), so as to be able to provide optimal fluid and energy intake.
METHODS—Twenty four babies with RDS and 19 healthy preterm babies, with gestational ages ranging from 26-36 weeks, were studied daily for the first week after birth. Total body water (TBW) was measured using bioelectrical impedance analysis. The babies were weighed daily and a record made of fluid and energy intake. Body solids were calculated as the difference between body weight and TBW.
RESULTS—There was a highly significant reduction in body weight by the end of the week, with the RDS babies losing more than the healthy babies (RDS 7.6%; non-RDS 3.7%). There was no significant difference in the amount of TBW at birth in the babies with and without RDS (RDS 85.1%; non-RDS 85.5%) and both groups lost the same amount of body water (RDS 10.9%; non-RDS 9.9%) by the end of the first week. The amount of total body water lost was unrelated to the volume of fluid administered. There was a loss of body solids during the first day in the RDS group, but, overall, there was a highly significant increase in both groups between birth and day 7, which was greater in the healthy babies (RDS 13.0%; non-RDS 42.7%).
CONCLUSIONS—Loss of body water after birth occurs to the same extent in healthy preterm neonates and in babies with RDS and is unrelated to the volume of fluid administered. Given adequate nutritional support, an increase in body solids can accompany early postnatal weight loss and begins almost immediately after birth, in both healthy preterm babies and babies with RDS.

     

Effects of dopamine and dobutamine on the myocardial and systemic circulation during and following cardiopulmonary bypass in dogs

Summary The effect of dopamine (Dp) and dobutamine (Db) on myocardial and systemic blood flow (BF) distribution was compared in dogs being weaned from cardiopulmonary bypass (CPB) after 20 min of normothermic global myocardial ischemia. Drug infusions (10 mcg/kg/min) were begun and BF was measured (radiolabeled microspheres) prior to weaning and 60 min off CPB.On CPB: Pump flows, by design, were similar (100 ml/kg/min) in Dp, Db, and saline control (NS) dogs. Dp and Db significantly (p<0.05) increased myocardial BF. Dp did not alter renal, visceral, and skeletal muscle BF and only increased BF to the cervical spinal cord and medulla. Db, however, significantly reduced renal (–49%), splenci (–58%), pancreatic (–27%), and colonic (–47%) BF but increased perfusion in essentially all of the central nervous system.Off CPB: Cardiac output during Dp and Db infusions was significantly greater than NS dogs (107±7 vs 152±12 vs 82±10 ml/kg/min resp.); the greater increase for Db resulting from a larger stroke volume. Dp and Db significantly increased myocardial BF. Dp increased splenic (+77%), gastric (+139%), and gallbladder (+125%) BF but had no effect on renal, hepatic, skeletal muscle, and intestinal BF. Db infusion maintained renal BF similar to NS and elevated BF to most visceral organs. The results of this study show that the myocardium responded to inotropic stimulation despite the previous ischemic insult but the BF changes varied among regional vascular beds with Dp and Db infusions during and following CPB. Of the 2 drugs, Db showed the greater inotropic response off CPB, a similar increase in myocardial perfusion and greater visceral organ bloodflow.Supported in part by Grants HL26640, HL 18204 and HL06185 from the National Institutes of Health and by a Grant-in-Aid from the American Heart Association Minnesota AffiliateThis paper was part of the Ray C. Anderson Symposium.     

Decreased renal perfusion after correction of experimental coarctation

Hemodynamical changes in coarctation were studied with an experimental model. Coarctation of the thoracic aorta was induced in seven puppies at the age of 8 wk. After a 7-month follow-up period a corrective operation with a venous patch was performed. Two dogs were lost a few hours after the correction operation. The remaining five dogs were followed for 12 months postoperatively. Renal perfusion was measured with a 133Xenon washout method just prior to the operation, 1 h, 6 and 12 months postoperatively. The glomerular filtration rate was measured using the 51Cr-EDTA method 1 wk before the operation, 3 wk, 2, 6, and 12 months after it. Six healthy adult dogs were used as controls for glomerular filtration rate measurements. Peripheral renin activity was measured at operation, just before the correction of aortic coarctation, 1/2, 1 h, 1, 3, 7 days, 2 and 6 months after the correction operation. Renal perfusion decreased significantly (p less than 0.05) immediately after the correction operation and rose again during the follow-up. Peripheral renin activity rose significantly (p less than 0.01) from the preoperative values and was at its greatest 1 day after the operation. Later on, peripheral renin activity values returned to normal. Coarctated dogs had significantly (p less than 0.01) lower glomerular filtration rate values than controls in each measurement except at the 2 months postoperative measurement. These results support decreased renal perfusion with resultant increased peripheral renin activity as part of the pathomechanism of the paradoxical hypertension observed after correction of coarctation.     

Total energy expenditure, body composition and weight gain in moderately preterm and full-term infants at term postconceptional age

AIM: To assess total energy expenditure (TEE) and body composition, i.e. total body water (TBW) and adipose tissue volume (ATV), at term age in 8 healthy preterm infants, born between gestational weeks 30 and 33, and in 9 healthy full-term newborns. METHODS: Total and subcutaneous ATVs were assessed using magnetic resonance imaging, while TEE and TBW were estimated using doubly labelled water. RESULTS: Total ATV was 272 +/- 21 and 261 +/- 56 ml/kg body weight, while subcutaneous ATV was 88.9 +/- 1.6 and 89.7 +/- 2.0% of total ATV for preterm and full-term infants, respectively. The corresponding figures for TBW (as percentage of body weight) were 67.4 +/- 2.5 and 68.1 +/- 4.1, respectively. A significant correlation between ATV/kg body weight and body weight was found for full-term (p < 0.0001) but not for preterm infants. TEE for preterm infants was 315 +/- 20 kJ/kg body weight/24 h, which was significantly higher (p < 0.05) than TEE for full-term infants (254 +/- 45 kJ/kg body weight/24 h). At the time of investigation preterm infants weighed significantly (p < 0.05) less (540 g) than full-term infants. After the time of investigation, weight gains of preterm and full-term infants were 38 +/- 12 and 24 +/- 14 g/24 h, respectively. CONCLUSION: When compared to full-term newborns, predominantly breastfed healthy preterm infants at term postconceptional age were significantly smaller, had a similar average proportion of body fat and showed catch-up growth. Their higher TEE/kg body weight can be explained by a higher growth rate and possibly also by higher physical activity.     

Plasma vascular endothelial growth factor level is a predictor of the severity of postoperative capillary leak syndrome in neonates undergoing cardiopulmonary bypass

 Capillary leak syndrome (CLS), characterized by extravascular fluid accumulation and significant organ dysfunction, is a serious complication in children undergoing cardiopulmonary bypass (CPB). We examined the relationship between plasma vascular endothelial growth factor (VEGF) levels and severity of CLS. The kinetics of VEGF in the plasma of 11 neonates and 7 older children undergoing CPB were investigated, correlating plasma VEGF levels and CLS clinical presentation. The degree of postoperative CLS was quantified by measuring parameters of extracellular volume and end-organ dysfunction. A chest-wall soft-tissue-width index (CSTWI) was designed in order to standardize the extracellular fluid accumulation. Most CLS parameters were significantly more prominent in the neonatal patients. Low plasma VEFG levels (>35 pg/ml) were found in 3 neonatal control patients and all but, sample from the older group patient. The neonates had significantly higher preoperative VEGF plasma levels (684.4 ± 559.1 pg/ml, P = 0.02), which decreased during the operation to levels below 35 pg/ml and increased again 24 h postoperatively to levels significantly higher than in the older patients (484 ± 270.3 pg/ml, P = 0.001). Multilinear regression analysis found preoperative VEGF levels to independently correlate with CLS as represented by CSTWI (P < 0.01, r = 0.726). Both the occurrence of post-CPB CLS and plasma VEGF levels pre- and postoperatively were thus higher in neonates than in children. Plasma VEGF level is a predictor of the severity of postoperative CLS. Accepted: 1 March 2000     

Prediction of total body water in infants and children.

BACKGROUND: In paediatric clinical practice treatment is often adjusted in relation to body size, for example the calculation of pharmacological and dialysis dosages. In addition to use of body weight, for some purposes total body water (TBW) and surface area are estimated from anthropometry using equations developed several decades previously. Whether such equations remain valid in contemporary populations is not known. METHODS: Total body water was measured using deuterium dilution in 672 subjects (265 infants aged <1 year; 407 children and adolescents aged 1-19 years) during the period 1990-2003. TBW was predicted (a) using published equations, and (b) directly from data on age, sex, weight, and height. RESULTS: Previously published equations, based on data obtained before 1970, significantly overestimated TBW, with average biases ranging from 4% to 11%. For all equations, the overestimation of TBW was greatest in infancy. New equations were generated. The best equation, incorporating log weight, log height, age, and sex, had a standard error of the estimate of 7.8%. CONCLUSIONS: Secular trends in the nutritional status of infants and children are altering the relation between age or weight and TBW. Equations developed in previous decades significantly overestimate TBW in all age groups, especially infancy; however, the relation between TBW and weight may continue to change. This scenario is predicted to apply more generally to many aspects of paediatric clinical practice in which dosages are calculated on the basis of anthropometric data collected in previous decades.     

小儿心内直视手术后急性呼吸窘迫综合征的危险因素与防治对策

目的 分析小儿心内直视手术后发生急性呼吸窘迫综合征(ARDS)的危险因素及探讨其防治对策.方法 以2001年1月至2008年10月间连续1 408例施行先天性心脏病(先心病)手术患儿为研究对象,进行术后ARDS危险因素的单因素分析和多因素Logistic回归分析.结果 术后发生ARDS 32例,发生率为2.27%.术后ARDS患儿病死率为46.9%.单因素分析显示:紫绀型先心病、体外循环时同、主动脉阻断时间、呼吸机通气时间、每公斤体质量引流液总量、围手术期意外、术后并发症与术后ARDS有关.经多因素Logistic回归分析显示:体外循环时间超过180 min、每公斤体质量引流液总量超过18 ml、围术期发生意外、术后多器官功能衰竭为小儿心内直视手术后ARDS的危险因素.结论 对于具有ARDS高危因素的心内直视手术患儿,应采取积极的防治措施,这对防止心内直视手术后发生的ARDS具有重要的意义.     

PART I. TOTAL BODY WATER IN NORMAL ADOLESCENT MALES

This study was undertaken to obtain total body water (TBW) data suitable for derivation of body composition of the typical adolescent male. TBW by the deuterium dilution method, stage of sexual development and anthropometric parameters (weight, height and triceps and subscapular skinfold thickness) were determined in 108 males between 10 and 14 years of age, whose weight and height fell between the 10th and the 90th percentile of the NCHS reference data.
TBW/weight did not change significantly between 10 and 14 years, although a slight increase after age 11 years and from genital stage 2 to stage 5 was present. This indicates that body fat content decreases after 11 years and after genital stage 2, especially if the fact is taken into account that water content of fat-free body mass decreases during this age period.
The ability of single anthropometric parameters to predict TBW/weight was low (subscapular skinfold thickness, r = -0.62; triceps skinfold thickness, r = -0.54; weight/height cube ratio, r = -0.48). Even with the use of various combinations of anthropometric parameters in multiple stepwise prediction equations it was not possible to explain more than 50% of the variation of TBW/weight and the high standard error of the estimate indicated large errors in prediction. Thus, body composition of normal adolescent males cannot be predicted with an acceptable degree of accuracy by anthropometric parameters. On the other hand, the deuterium dilution method using salivary water represents a noninvasive method for the determination of TBW which is quite simple and suitable for field studies.     

Changes in body composition during the initial hours of life in breast-fed healthy term newborns

Newborns usually lose 5-10% of their initial weight during the first 4 days of life. Our aim, using bioelectrical impedance (BI), was to study the body composition of healthy term newborns and the nature of the changes which accompany this physiological weight loss. Forty-three healthy term newborns, all with adequate weight for their gestational age, were studied during the first 3 days of life. Weight and BI were taken on the 1st, 2nd, and 3rd days of life, always at the same time of the day. Total body water (TBW), percentage of total body mass hydration (%TBW), and amount of body solids were calculated. Average weight at birth was 3,297+/-381 g, length 50.04+/-1.75 cm, and gestational age 39.9+/-0.84 weeks. Weight, TBW, and body solids decreased progressively during the first 3 days of life (p<0.000). By day 3, weight loss represented 5.67+/-1.98% of birth weight, but %TBW increased slightly (1.72%; p<0.000). These results suggest that, during physiological weight loss, body composition modifications are produced in the term newborn by a decrease in TBW and loss of body solids. The level of body hydration increases slightly, since the loss of body solids is greater than the loss of TBW. The use of BI can help us in the study of body composition and the short- and/or long-term changes produced therein, in the newborn.     

Body composition of children in south-western Nigeria: validation of bio-electrical impedance analysis

Bio-electrical impedance analysis (BIA) is a non-invasive method of estimating body composition and has the potential to be useful in clinics and for nutrition and health-related research in Africa. We sought to validate BIA for use among a Yoruba population in south-western Nigeria and to use BIA to assess the body composition of a healthy cohort of children. Total body water (TBW) was measured in 92 individuals (53 adults and 39 children) using deuterium dilution; height, weight and resistance were measured by BIA. Multiple regression analysis was used to develop prediction equations for TBW among children only or among all participants. Independent covariates tested in the regression models included the impedance index (height(2)/resistance), weight, age and gender with TBW as the dependent variable. Depending on the model used, between 97% (root MSE=0.7 kg ) and 99% (root MSE=0.7 kg) of the variance observed in TBW could be explained by the impedance index, weight and/or gender; age, however, was not significant in any model. In a separate cohort of 69 children, 5-8 years old, anthropometrics were measured and TBW was estimated using the developed equations. Body composition data are presented by gender and age group. BIA was validated for use among Nigerian children and adults and provides a potentially important tool for research.     

Total body electrical conductivity used to determine body composition in infants

Total body electrical conductivity (TOBEC) has been introduced as a rapid, safe, and noninvasive method suitable for the estimation of fat-free mass. The instrument (EMME or TOBEC) operates on the principle that organisms placed in an electromagnetic field perturb the field to a degree that depends on the amount and volume of distribution of electrolytes present. A study was designed to measure body composition in infants by the TOBEC method and to compare the results with those obtained using the isotope dilution technique. Sixteen infants (age range, 2 days to 9.7 months; weight range, 2 to 8.7 kg) were enrolled. Total body water (TBW) was determined by the isotope dilution technique using H218O. There was a good correlation between the natural logarithm of the TOBEC number and TBW, with a linear correlation coefficient of 0.949. The fat-free body mass of the infants was calculated by TBW (fat-free body mass = /0.082) and by the TOBEC method using the standard previously derived from mature rabbits. TBW measurements by H218O dilution appeared to overestimate fat-free mass which was greater than TBW in five of the 16 infants. Measured by the TOBEC method, fat-free mass ranged from 51 to 91% of total body weight. The TOBEC method is highly suitable for use with human infants and appears to determine body composition as accurately as other available methods.     

Validation of Simple Epidemiological or Clinical Methods for the Measurement of Body Composition in Young Children

Objective:

The present study aimed to determine the validity of simple epidemiological and clinical methods for the assessment of body fatness in preschool children.

Methods:

In 89 children (42 boys, 47 girls; mean age 4.1 SD 1.3y) measures of body fatness were made using total body water (TBW), dual energy x-ray absorptiometry (DXA), air displacement plethysmography (BODPOD) and skinfold thickness. Methods were compared by Bland–Altman analysis using TBW as the reference method, and by paired comparisons and rank order correlations.

Findings:

Bias for DXA was +1.8% body fat percentage units (limits of agreement +15.5% to −11.9%), bias for BODPOD was −3.5% (limits of agreement +18.9% to −5.9%) and bias for skinfolds using the Slaughter equations was −6.5% (limits of agreement +10.0% to −23.1%). Significant rank order correlations with TBW measures of fatness were obtained for DXA estimates of fatness (r=0.54, P=0.01), but not for estimates of fat by skinfold thickness (r=0.20, P=0.2) or BODPOD (r=0.25, P=0.1). Differences between both DXA and BODPOD and the reference TBW estimates of body fatness were not significant (P=0.06 and P=0.1 respectively); however, the difference in estimated body fatness between skinfold thickness and TBW was significant (P<0.001).

Conclusion:

Estimates of body fatness in preschool children were inaccurate at the level of the individual child using all the methods, but DXA might provide unbiased estimates and a means of making relative assessments of body fatness.     

珠江三角洲新生儿转运网络工作报告

目的　评价珠江三角洲新生儿转运网络（ｎｅｏｎａｔａｌｔｒａｎｓｐｏｒｔｎｅｔｗｏｒｋ, ＮＴＮ） 十年工作及其效果。方法　介绍新生儿转运网络方法及分析有关效果的资料。结果　转运网络现有８７ 家医院;１０ 年共转运急危重症新生儿８ １２４ 例,转运途中死亡３５ 例,病死率为０．４３％ ;第三级新生儿监护病房（ＮＩＣＵ）收容８ ０８９ 例,共死亡３６４ 例,病死率为４．５０ ％ ,ＮＴＮ 医院中总死亡率为２．０７‰。结论　该ＮＴＮ 所实行的运转机制合理适用;促进了网络单位包括三级ＮＩＣＵ 的发展与提高;建立ＮＴＮ是降低新生儿死亡率的重要措施。     

小儿体外循环心脏术后呼吸机相关性肺炎的危险因素分析

目的 探讨小儿体外循环心脏术后呼吸机相关性肺炎(ventilator-associated pneu monia,VAP)的危险因素.方法对2003年1月至2010年6月连续体外循环(cardiopulmonany bypass,CPB)心脏术后机械通气时间超过48 h的116例患儿的临床资料进行回顾性分析,根据发生VAP与否进行分组,并进行术后VAP的单因素和多因素Logistic回归分析.结果CPB心脏术后VAP总发病率为4.18％(57/1 365),发生VAP患儿病死率为26.32％(15/57).单因素分析显示:重度肺动脉高压、CPB时间、主动脉阻断时间、二次体外循环支持、白蛋白、术后PaO2/FiO2、机械通气时间、每千克体质量引流液总量、二次气管插管、气管切开、留置胃管、应激性溃疡预防用药与术后发生VAP有关.经多因素Logistic回归分析显示:CPB时间≥150m in、机械通气时间≥4 d、每千克体质量引流液总量≥18ml和气管切开为小儿CPB术后发生VAP的危险因素.57例VAP患儿中共培养病原菌90株,其中革兰阴性菌54株(60.0％),革兰阳性菌32株(35.6％),真菌4株(4.4％).结论临床上可根据VAP的危险因素预先采取措施,以减少VAP的发生.     

Leptin levels in breast-fed and formula-fed infants

Aim: Leptin, a hormone that regulates food intake and energy metabolism, is present in breast milk and thus may be involved in body composition differences between breastfed and formula-fed infants. The aim of this study was to evaluate whether diet and gender affect plasma leptin concentration in breastfed and formula-fed infants during the first months of life. Methods: Anthropometric and bioelectrical impedance measurements [total body water (TBW) calculated with the Fjeld equation] were made and venous blood plasma samples were analysed for leptin concentration in healthy, exclusively breastfed or formula-fed Italian infants in the first year of life. Infants were subdivided in two ways: three groups (periods) in relation to age, and five groups in relation to weight. Results: The average serum concentration of leptin was 7.35 ng ml -1 . Serum leptin values were higher in breastfed than in formula-fed infants. Breastfed infants in group 1 had a statistically higher serum leptin concentration (2500-3749 g). There were no significant differences in anthropometric measurements, body mass index or skinfold thickness between breastfed and formula-fed infants. In the periods I and II, breastfed infants had a significantly higher TBW than formula-fed infants. Males had a significantly higher TBW than females in periods I and II. Breastfed infants in group 2 (3750-4999 g) had a significantly higher TBW than formula-fed infants.

Conclusion: The data on TBW, weight and skinfold thickness suggest that the higher leptin concentration observed in breastfed infants in the first months of life may be due not only to adipose tissue production but also to human milk.     

Weight minus extracellular fluid as metabolic reference standard in newborn baby

In 51 babies of differing size and gestational age, rates of oxygen consumption and corrected bromide space (as a measure of extracellular fluid) were measured. The results are used to examine the concept that weight minus extracellular fluid (ECF) is an appropriate metabolic reference standard in the newborn baby. When the whole group, which included large-for-dates and small-for-dates babies, is considered there is a systematic variation wherein the rate of oxygen consumption thus expressed varies with size. However, when appropriately grown babies only are considered, who varied in birthweight from 1210 g to 3820 g, rates of oxygen consumption thus expressed were constant. The implication is that when unusual rates of oxygen consumption per kilogram body weight are found, they should be interpreted bearing in mind the possibility of an unusual proportion of ECF in the baby. An incidental finding was that small-for-dates babies have a relatively large corrected bromide space.