Nutrition and Indirect Calorimetry

Nutrition support is important in the care of patients with both acute and chronic illness. Optimizing nutritional support for the critically ill and patients with acute and chronic respiratory disorders has been shown to shorten length of stay, shorten duration of mechanical ventilation, lower health-care costs and reduce morbidity and mortality while improving functional quality of life. Nutritional requirements are difficult to predict in patients diagnosed with cancer due to their disease processes, altered inflammatory responses and metabolic rates among many other variables. Often predictive equations are used to estimate energy requirements and the average dietary energy intake needed to maintain energy balance. Energy requirements can be estimated through the use of over 200 predictive equations. Utilization of indirect calorimetry as the ‘gold standard’ for measuring resting metabolic rate (RMR) and resting energy expenditure (REE) can provide support in all states of health and disease. This chapter will identify and discuss the role of indirect calorimetry, examine the reasons why indirect calorimetry is more reliable than predictive equations in determining a patient’s calorie requirement, and when it is most applicable to incorporate indirect calorimetry measurements in the care of cancer patients

Validation of five minimally obstructive methods to estimate physical activity energy expenditure in young adults in semi-standardized settings

We compared the accuracy of five objective methods, including two newly developed methods combining accelerometry and activity type recognition (Acti4), against indirect calorimetry, to estimate total energy expenditure (EE) of different activities in semi-standardized settings. Fourteen participants performed a standardized and semi-standardized protocol including seven daily life activity types, while having their EE measured by indirect calorimetry. Simultaneously, physical activity was quantified by an ActivPAL3, two ActiGraph GT3X+’s and an Actiheart. EE was estimated by the standard ActivPAL3 software (ActivPAL), ActiGraph GT3X+ (ActiGraph) and Actiheart (Actiheart), and by a combination of activity type recognition via Acti4 software and activity counts per minute (CPM) of either a hip- or thigh-worn ActiGraph GT3X+ (AGhip + Acti4 and AGthigh + Acti4). At group level, estimated physical activities EE by Actiheart (MSE = 2.05) and AGthigh + Acti4 (MSE = 0.25) were not significantly different from measured EE by indirect calorimetry, while significantly underestimated by ActiGraph, ActivPAL and AGhip + Acti4. AGthigh + Acti4 and Actiheart explained 77% and 45%, of the individual variations in measured physical activity EE by indirect calorimetry, respectively. This study concludes that combining accelerometer data from a thigh-worn ActiGraph GT3X+ with activity type recognition improved the accuracy of activity specific EE estimation against indirect calorimetry in semi-standardized settings compared to previously validated methods using CPM only

Necessidades nutricionais do doente crítico

Objective: Given the inaccessibility of indirect calorimetry, intensive care units generally use predictive equations or recommendations that are established by international societies to determine energy expenditure. The aim of the present study was to compare the energy expenditure of critically ill patients, as determined using indirect calorimetry, to the values obtained using the Harris-Benedict equation. Methods: A retrospective observational study was conducted at the Intensive Care Unit 1 of the Centro Hospitalar do Porto. The energy requirements of hospitalized critically ill patients as determined using indirect calorimetry were assessed between January 2003 and April 2012. The accuracy (± 10% difference between the measured and estimated values), the mean differences and the limits of agreement were determined for the studied equations. Results: Eighty-five patients were assessed using 288 indirect calorimetry measurements. The following energy requirement values were obtained for the different methods: 1,753.98±391.13 kcal/ day (24.48 ± 5.95 kcal/kg/day) for indirect calorimetry and 1,504.11 ± 266.99 kcal/day (20.72±2.43 kcal/kg/day) for the HarrisBenedict equation. The equation had a precision of 31.76% with a mean difference of -259.86 kcal/day and limits of agreement between -858.84 and 339.12 kcal/day. Sex (p=0.023), temperature (p=0.009) and body mass index (p< 0.001) were found to significantly affect energy expenditure Conclusion: The Harris-Benedict equation is inaccurate and tends to underestimate energy expenditure. In addition, the Harris-Benedict equation is associated with significant differences between the predicted and true energy expenditure at an individual levelinfo:eu-repo/semantics/publishedVersio

Energy expenditure in critically ill patients estimated by population-based equations, indirect calorimetry and CO2-based indirect calorimetry

Background: Indirect calorimetry (IC) is the reference method for measurement of energy expenditure (EE) in mechanically ventilated critically ill patients. When IC is unavailable, EE can be calculated by predictive equations or by VCO2-based calorimetry. This study compares the bias, quality and accuracy of these methods. Methods: EE was determined by IC over a 30-min period in patients from a mixed medical/postsurgical intensive care unit and compared to seven predictive equations and to VCO2-based calorimetry. The bias was described by the mean difference between predicted EE and IC, the quality by the root mean square error (RMSE) of the difference and the accuracy by the number of patients with estimates within 10 % of IC. Errors of VCO2-based calorimetry due to choice of respiratory quotient (RQ) were determined by a sensitivity analysis, and errors due to fluctuations in ventilation were explored by a qualitative analysis. Results: In 18 patients (mean age 61 ± 17 years, five women), EE averaged 2347 kcal/day. All predictive equations were accurate in less than 50 % of the patients with an RMSE ≥ 15 %. VCO2-based calorimetry was accurate in 89 % of patients, significantly better than all predictive equations, and remained better for any choice of RQ within published range (0.76–0.89). Errors due to fluctuations in ventilation are about equal in IC and VCO2-based calorimetry, and filtering reduced these errors. Conclusions: This study confirmed the inaccuracy of predictive equations and established VCO2-based calorimetry as a more accurate alternative. Both IC and VCO2-based calorimetry are sensitive to fluctuations in respiration.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Comparação entre equações preditivas do gasto energético basal e calorimetria indireta em ginastas

Aim: to compare equations for estimating resting energy expenditure with values obtained by indirect calorimetry from rhythmic and artistic gymnasts. Methods: cross-sectional study with a convenience sample of 11 female gymnasts of a sports club in Porto Alegre, Brazil, that were evaluated about body fat percent, resting energy expenditure obtained by indirect calorimetry and by predictive equations of Harris-Benedict, Henry &amp; Rees, FAO/WHO, Schofield, Katch &amp; McArdle and the Institute of Medicine. Results: all athletes had healthy body fat percentages and none of the equations tested was correlated with the results of indirect calorimetry, especially not when resting energy expenditure according to indirect calorimetry was greater than 1400 calories. The Harris-Benedict equation differed the least from indirect calorimetry among all tested equations. resting energy expenditure by indirect calorimetry did not correlate to body composition, age, time since menarche or training. Conclusions: based on obtained data the predictive equations studied for estimating resting energy expenditure were not similar to the indirect calorimetry results, although the Harris-Benedict equation exhibited the smallest difference. Further studies are needed to elucidate this findings. RESUMOComparação entre equações preditivas do gasto energético basal e calorimetria indireta em ginastasObjetivo: comparar as equações para estimativa do gasto energético de repouso com os valores obtidos por calorimetria indireta em atletas de ginástica artística e rítmica. Métodos: estudo transversal realizado com uma amostra de conveniência de 11 atletas do sexo feminino de um clube esportivo de Porto Alegre, Brasil, avaliadas em relação ao percentual de gordura corporal, gasto energético de repouso obtido por calorimetria indireta e pelas equações preditivas de Harris-Benedict, Henry e Rees, FAO/OMS, Schofield, Katch e McArdle e do Instituto de Medicina. Resultados: todas as atletas tinham percentual de gordura adequado e nenhuma das equações testadas se correlacionou com os resultados obtidos por carolimetria indireta, especialmente quando o gasto energético de repouso por calorimetria indireta foi maior do que 1400 calorias. Dentre todas as equações, a equação de Harris-Benedict foi a que menos diferiu da calorimetria indireta. O gasto energético de repouso por calorimetria indireta também não se correlacionou com a composição corporal, idade, tempo de menarca ou tempo de treinamento. Conclusões: baseado nos dados obtidos, nenhuma das equações preditivas estudadas para estimativa do gasto energético de repouso foram similares aos resultados da calorimetria indireta, embora a equação de Harris-Benedict exibiu a menor diferença. Mais estudos são necessários para melhor entender estes resultados.Objetivo: comparar as equações para estimativa do gasto energético de repouso com os valores obtidos por calorimetria indireta em atletas de ginástica artística e rítmica. Métodos: estudo transversal realizado com uma amostra de conveniência de 11 atletas do sexo feminino de um clube esportivo de Porto Alegre, Brasil, avaliadas em relação ao percentual de gordura corporal, gasto energético de repouso obtido por calorimetria indireta e pelas equações preditivas de Harris-Benedict, Henry e Rees, FAO/OMS, Schofield, Katch e McArdle e do Instituto de Medicina. Resultados: todas as atletas tinham percentual de gordura adequado e nenhuma das equações testadas se correlacionou com os resultados obtidos por carolimetria indireta, especialmente quando o gasto energético de repouso por calorimetria indireta foi maior do que 1400 calorias. Dentre todas as equações, a equação de Harris-Benedict foi a que menos diferiu da calorimetria indireta. O gasto energético de repouso por calorimetria indireta também não se correlacionou com a composição corporal, idade, tempo de menarca ou tempo de treinamento. Conclusões: baseado nos dados obtidos, nenhuma das equações preditivas estudadas para estimativa do gasto energético de repouso foram similares aos resultados da calorimetria indireta, embora a equação de Harris-Benedict exibiu a menor diferença. Mais estudos são necessários para melhor entender estes resultados. ABSTRACTComparison between equations for estimation of resting energy expenditure and indirect calorimetry in gymnastsAim: to compare equations for estimating resting energy expenditure with values obtained by indirect calorimetry from rhythmic and artistic gymnasts. Methods: cross-sectional study with a convenience sample of 11 female gymnasts of a sports club in Porto Alegre, Brazil, that were evaluated about body fat percent, resting energy expenditure obtained by indirect calorimetry and by predictive equations of Harris-Benedict, Henry &amp; Rees, FAO/WHO, Schofield, Katch &amp; McArdle and the Institute of Medicine. Results: all athletes had healthy body fat percentages and none of the equations tested was correlated with the results of indirect calorimetry, especially not when resting energy expenditure according to indirect calorimetry was greater than 1400 calories. The Harris-Benedict equation differed the least from indirect calorimetry among all tested equations. resting energy expenditure by indirect calorimetry did not correlate to body composition, age, time since menarche or training. Conclusions: based on obtained data the predictive equations studied for estimating resting energy expenditure were not similar to the indirect calorimetry results, although the Harris-Benedict equation exhibited the smallest difference. Further studies are needed to elucidate this findings. Â

Comparação entre equações preditivas do gasto energético basal e calorimetria indireta em ginastas

Aim: to compare equations for estimating resting energy expenditure with values obtained by indirect calorimetry from rhythmic and artistic gymnasts. Methods: cross-sectional study with a convenience sample of 11 female gymnasts of a sports club in Porto Alegre, Brazil, that were evaluated about body fat percent, resting energy expenditure obtained by indirect calorimetry and by predictive equations of Harris-Benedict, Henry & Rees, FAO/WHO, Schofield, Katch & McArdle and the Institute of Medicine. Results: all athletes had healthy body fat percentages and none of the equations tested was correlated with the results of indirect calorimetry, especially not when resting energy expenditure according to indirect calorimetry was greater than 1400 calories. The Harris-Benedict equation differed the least from indirect calorimetry among all tested equations. resting energy expenditure by indirect calorimetry did not correlate to body composition, age, time since menarche or training. Conclusions: based on obtained data the predictive equations studied for estimating resting energy expenditure were not similar to the indirect calorimetry results, although the Harris-Benedict equation exhibited the smallest difference. Further studies are needed to elucidate this findings.Comparação entre equações preditivas do gasto energético basal e calorimetria indireta em ginastas Objetivo: comparar as equações para estimativa do gasto energético de repouso com os valores obtidos por calorimetria indireta em atletas de ginástica artística e rítmica. Métodos: estudo transversal realizado com uma amostra de conveniência de 11 atletas do sexo feminino de um clube esportivo de Porto Alegre, Brasil, avaliadas em relação ao percentual de gordura corporal, gasto energético de repouso obtido por calorimetria indireta e pelas equações preditivas de Harris-Benedict, Henry e Rees, FAO/OMS, Schofield, Katch e McArdle e do Instituto de Medicina. Resultados: todas as atletas tinham percentual de gordura adequado e nenhuma das equações testadas se correlacionou com os resultados obtidos por carolimetria indireta, especialmente quando o gasto energético de repouso por calorimetria indireta foi maior do que 1400 calorias. Dentre todas as equações, a equação de Harris-Benedict foi a que menos diferiu da calorimetria indireta. O gasto energético de repouso por calorimetria indireta também não se correlacionou com a composição corporal, idade, tempo de menarca ou tempo de treinamento. Conclusões: baseado nos dados obtidos, nenhuma das equações preditivas estudadas para estimativa do gasto energético de repouso foram similares aos resultados da calorimetria indireta, embora a equação de Harris-Benedict exibiu a menor diferença. Mais estudos são necessários para melhor entender estes resultados

Fasting substrate oxidation at rest assessed by indirect calorimetry: is prior dietary macronutrient level and composition a confounder?

Indirect calorimetry, the measurement of O₂ consumption and CO₂ production, constitutes an invaluable tool as the most common method for analyzing whole-body energy expenditure, and also provides an index of the nature of macronutrient substrate oxidation—namely, carbohydrate (CHO) versus fat oxidation. The latter constitutes a key etiological factor in obesity as this condition can only develop when total fat oxidation is chronically lower than total exogenous fat intake. The standardization of indirect calorimetry measurements is essential for accurately tracking the relative proportion of energy expenditure derived from CHO and fat oxidation. Here we analyze literature data to show that the average fasting respiratory quotient typically shifts from approximately 0.80 to 0.90 (indicating a doubling of resting CHO oxidation) in response to a switch in dietary CHO intake (as % energy) from 30 to 60%. This underscores the importance of taking into account dietary macronutrient composition prior to indirect calorimetry studies in the interpretation of data on substrate utilization and oxidation

Some applications of indirect calorimetry to sports medicine

Some applications of indirect calorimetry to sports medicine are discussed and exemplified by case reports. In particular, it is suggested that oxigen consumption can be employed to assess the effects of physical activity on fat-free tissues and that the respiratory quotient may offer some insights into the food habits of athletes

Calibration and Cross-Validation of Accelerometery for Estimating Movement Skills in Children Aged 8-12 Years

This study sought to calibrate triaxial accelerometery, worn on both wrists, waist and both ankles, during children’s physical activity (PA), with particular attention to object control motor skills performed at a fast and slow cadence, and to cross-validate the accelerometer cut-points derived from the calibration using an independent dataset. Twenty boys (10.1 ±1.5 years) undertook seven, five-minute bouts of activity lying supine, standing, running (4.5kmph−1) instep passing a football (fast and slow cadence), dribbling a football (fast and slow cadence), whilst wearing five GENEActiv accelerometers on their non-dominant and dominant wrists and ankles and waist. VO2 was assessed concurrently using indirect calorimetry. ROC curve analysis was used to generate cut-points representing sedentary, light and moderate PA. The cut-points were then cross-validated using independent data from 30 children (9.4 ± 1.4 years), who had undertaken similar activities whilst wearing accelerometers and being assessed for VO2. GENEActiv monitors were able to discriminate sedentary activity to an excellent level irrespective of wear location. For moderate PA, discrimination of activity was considered good for monitors placed on the dominant wrist, waist, non-dominant and dominant ankles but fair for the non-dominant wrist. Applying the cut-points to the cross-validation sample indicated that cut-points validated in the calibration were able to successfully discriminate sedentary behaviour and moderate PA to an excellent standard and light PA to a fair standard. Cut-points derived from this calibration demonstrate an excellent ability to discriminate children’s sedentary behaviour and moderate intensity PA comprising motor skill activity.N/