Assessment of total body water in paediatric patients on dialysis

Background Various anthropometric techniques are used to assess total body water in children on dialysis; however, their predictive accuracy and precision has not been validated. Methods We compared total body water measurements obtained by deuterium oxide (D2O) dilution with predictions of total body water from (1) height and weight, (2) skinfold measurements, and (3) bioelectrical impedance analysis, using previously published formulae for healthy children. Measurements were performed in 14 patients on peritoneal and in nine patients on haemodialysis, aged 4-22 years. Results In the total population of dialysed patients, weight was the strongest single predictor of total body water (R2=0.93) followed by the resistance index (RI=height2/impedance; R2=0.85) and height (R2=0.93). A prediction formula based on height and weight predicted total body water with a residual mean square error (RMSE) of 1.97 l (coefficient of variation (CV)=10.0%) and with a systematic overestimation of true total body water by 0.4%. A prediction equation based on skinfold measurements yielded a total body water estimate with an RMSE of 2.15 1 (CV=10.5%) and overpredicted true total body water by an average of 2.2%. Using three published prediction equations incorporating RI, RMSEs of 2.78 1 (CV=14.1%) with a mean under- or overestimation of true total body water by 6.9, 7.1, and 0.8% respectively, were achieved. The prediction of total body water was optimized by linear combinations of RI or the log-transformed sum of four skinfolds (logsum) with weight by the following equations: total body water (1) = 9.97−3.13×logsum +0.59×weight (kg) (1) (R2 = 0.951; RMSE=1.67 1; CV = 8.17%). total body water (1) = 1.99 + 0.144 × RI (Ohm/cm2) + 0.40 × weight (kg) (2) (R2 = 0.949; RMSE = 1.671; CV = 8.53%). The fit of these prediction formulae, which were derived from the total population, did not differ significantly between haemo- and peritoneal dialysis patients or between boys and girls. Conclusions Both skinfold measurements and bioelectrical impedance analysis can be used to improve the height- and weight- based prediction of total body water in children on dialysi

EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on Dietary reference values for water

This Opinion of the EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA) deals with the setting of dietary reference values for water for specific age groups. Adequate Intakes (AI) have been defined derived from a combination of observed intakes in population groups with desirable osmolarity values of urine and desirable water volumes per energy unit consumed. The reference values for total water intake include water from drinking water, beverages of all kind, and from food moisture and only apply to conditions of moderate environmental temperature and moderate physical activity levels (PAL 1.6). AIs for infants in the first half of the first year of life are estimated to be 100-190 mL/kg per day. For infants 6-12 months of age a total water intake of 800-1000 mL/day is considered adequate. For the second year of life an adequate total water intake of 1100-1200 mL/day is defined by interpolation, as intake data are not available. AIs of water for children are estimated to be 1300 mL/day for boys and girls 2-3 years of age; 1600 mL/day for boys and girls 4-8 years of age; 2100 mL/day for boys 9-13 years of age; 1900 mL/day for girls 9-13 years of age. Adolescents of 14 years and older are considered as adults with respect to adequate water intake. Available data for adults permit the definition of AIs as 2.0 L/day (P 95 3.1 L) for females and 2.5 L/day (P95 4.0 L) for males. The same AIs as for adults are defined for the elderly. For pregnant women the same water intake as in non-pregnant women plus an increase in proportion to the increase in energy intake (300 mL/day) is proposed. For lactating women adequate water intakes of about 700 mL/day above the AIs of non-lactating women of the same age are derive

Measurement of D2O Concentrations at Tracer Levels in Small Samples Obtained from Paediatric Patients

Peer Reviewe

Fourier Transform Infrared Spectroscopy Measures 1H/2H Ratios of Native Water with a Precision Comparable to that of Isotope Ratio Mass Spectrometry

Peer Reviewe