Implications of the variability in time to isotopic equilibrium in the deuterium dilution technique

Colley, Rachel C.; Byrne, Nuala M.; Hills, Andrew P.

doi:10.1038/sj.ejcn.1602653

Cited by 22 publications

(23 citation statements)

References 22 publications

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“…TBW estimation can then be accurately performed based on the atom percentage of the radioisotope compared with water in the sample (25) . Although the test is very effective for assessing the fl uid volume in a patient with abnormal homeostasis, it is unfortunately impractical given the time (often more than 6 h) required for equilibration (26,27) . Therefore, accurate, and even more importantly, practical measures of hydration status are still necessary for the evaluation of patients in a timely manner.…”

Section: Isotopic Tracers Of Water -The Gold Standard For Tbw Measurementioning

confidence: 99%

The emerging role of biomarkers and bio-impedance in evaluating hydration status in patients with acute heart failure

Somma¹,

Navarin²,

Giordano³

et al. 2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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The quantitative and qualitative estimation of total body fl uid content has proven to be crucial for both diagnosis and prognosis assessment in patients with heart failure. The aim of this review is to summarize the current techniques for assessing body hydration status as well as the principal biomarkers associated with acute heart failure (AHF). Although clinical history, physical examination and classical imaging techniques (e.g., standard radiography and echocardiography) still represent the cornerstones, novel and promising tools, such as biomarkers and bio-electrical impedance are achieving an emerging role in clinical practice for the assessment of total body fl uid content. In the acute setting, the leading advantages of these innovative methods over device are represented by the much lower invasiveness and the reasonable costs, coupled with an easier and faster application. This article is mainly focused on AHF patients, not only because the overall prevalence of this disease is dramatically increasing worldwide, but also because it is well-known that their fl uid overload has a remarkable diagnostic and prognostic significance. It is thereby conceivable that the bio-electrical vector analysis (BIVA) coupled with laboratory biomarkers might achieve much success in AHF patient management in the future, especially for assisting diagnosis, risk stratifi cation, and therapeutic decision-making.

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Section: Isotopic Tracers Of Water -The Gold Standard For Tbw Measurementioning

confidence: 99%

The emerging role of biomarkers and bio-impedance in evaluating hydration status in patients with acute heart failure

Somma¹,

Navarin²,

Giordano³

et al. 2012

Clinical Chemistry and Laboratory Medicine (CCLM)

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“…Body composition was determined by dual energy X-ray absorptiometry (Lunar DPX, Lunar, Madison, WI) 23 and from measurements of total body water using the stable, nonradioactive, non-toxic isotope deuterium ( 2 H 2 O), as previously published. 24 Resting metabolic rate RMR was measured using a ventilated hood system (Deltatrac II, Datex, Helsinki, Finland) calibrated before each measurement with standardised gases. All testing was conducted between 0700 and 0900 hours after a 12-h overnight fast.…”

Section: Anthropometry and Body Compositionmentioning

confidence: 99%

Does metabolic compensation explain the majority of less-than-expected weight loss in obese adults during a short-term severe diet and exercise intervention?

et al. 2012

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OBJECTIVE:We investigated to what extent changes in metabolic rate and composition of weight loss explained the lessthan-expected weight loss in obese men and women during a diet-plus-exercise intervention. DESIGN: In all, 16 obese men and women (41 ± 9 years; body mass index (BMI) 39 ± 6 kg m À 2 ) were investigated in energy balance before, after and twice during a 12-week very-low-energy diet(565-650 kcal per day) plus exercise (aerobic plus resistance training) intervention. The relative energy deficit (EDef) from baseline requirements was severe (74%-87%). Body composition was measured by deuterium dilution and dual energy X-ray absorptiometry, and resting metabolic rate (RMR) was measured by indirect calorimetry. Fat mass (FM) and fat-free mass (FFM) were converted into energy equivalents using constants 9.45 kcal per g FM and 1.13 kcal per g FFM. Predicted weight loss was calculated from the EDef using the 0 7700 kcal kg À 1 rule 0 . RESULTS: Changes in weight ( À 18.6 ± 5.0 kg), FM ( À 15.5 ± 4.3 kg) and FFM ( À 3.1 ± 1.9 kg) did not differ between genders. Measured weight loss was on average 67% of the predicted value, but ranged from 39% to 94%. Relative EDef was correlated with the decrease in RMR (R ¼ 0.70, Po0.01), and the decrease in RMR correlated with the difference between actual and expected weight loss (R ¼ 0.51, Po0.01). Changes in metabolic rate explained on average 67% of the less-than-expected weight loss, and variability in the proportion of weight lost as FM accounted for a further 5%. On average, after adjustment for changes in metabolic rate and body composition of weight lost, actual weight loss reached 90% of the predicted values. CONCLUSION: Although weight loss was 33% lower than predicted at baseline from standard energy equivalents, the majority of this differential was explained by physiological variables. Although lower-than-expected weight loss is often attributed to incomplete adherence to prescribed interventions, the influence of baseline calculation errors and metabolic downregulation should not be discounted.

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“…The labelling of water molecules with deuterium enables the measurement of the dynamic character of body water. After consuming a dose of 2 H 2 O, the deuteriumlabelled water is distributed throughout the body water pool and commonly reaches a steady state concentration in approximately 3-6 h [24][25][26]. The body water pool size, or deuterium dilution space, can be measured based on the concentration of deuterium oxide in body water and the exact dose of deuterium-labelled water consumed.…”

Section: Deuterium Oxide Dilution Technique For the Assessment Of Bodmentioning

confidence: 99%

Stable Isotope Techniques to Develop and Monitor Nutrition Interventions

Hills¹,

Davidsson

2010

CNF

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A combination of industrialization, urbanization, economic development and globalization has resulted in rapid changes in diets and lifestyles for many populations. The impact of these changes is significant for the health and nutritional status of such populations, particularly in the developing world. The negative consequences of the nutrition transition include poor nutrition and decreased physical activity, with a corresponding increase in diet-related chronic diseases such as obesity, diabetes mellitus, cardiovascular disease, hypertension, stroke, osteoporosis and some cancers, particularly among the poor. The coexistence of chronic diseases and undernutrition of infants, children and women, and overnutrition in adults, has been referred to as the double burden of malnutrition.Stable isotope techniques are now in widespread use in applied nutrition, however, in this paper we discuss three of the techniques with particular relevance to the development and monitoring of nutrition interventions globally. These techniques include the doubly labelled water (DLW) technique of deuterium ( 2 H) and oxygen-18 ( 18 O) to assess total energy expenditure (TEE), the use of 2 H to estimate total body water (TBW) and assessment of body composition as well as the deuterium oxide 'dose-to-mother' technique to assess human milk intake in breastfed infants.

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Implications of the variability in time to isotopic equilibrium in the deuterium dilution technique

Cited by 22 publications

References 22 publications

The emerging role of biomarkers and bio-impedance in evaluating hydration status in patients with acute heart failure

The emerging role of biomarkers and bio-impedance in evaluating hydration status in patients with acute heart failure

Does metabolic compensation explain the majority of less-than-expected weight loss in obese adults during a short-term severe diet and exercise intervention?

Stable Isotope Techniques to Develop and Monitor Nutrition Interventions

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