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

The usefulness of a new indirect calorimeter in critically ill adult patients

Background &amp; aims: The use of indirect calorimetry to determine energy requirements is highly recommended in critically ill patients. To facilitate this a new and easy to use calorimeter (Q-NRG+, Cosmed) was developed. The primary aim of our study was to describe the usefulness of this calorimeter and, secondarily, to investigate the agreement between measured and predicted energy needs in a large cohort of critically ill adult patients. Methods: A prospective observational study was conducted among adult mechanically ventilated patients with COVID-19. Indirect calorimetry (Q-NRG+) to measure resting energy expenditure (mREE) was performed in the first week after admission and, wherever possible, repeated weekly. Reasons for not performing indirect calorimetry were reported. Parameters of indirect calorimetry and patient's conditions during the measurements were collected. Measurements were defined as valid if less than 10% overall variation in VO2 and VCO2 and respiratory quotient ranges between 0.67 and 1.1 were observed. mREE was compared with predictive REE (pREE) using standard formulas to explore hypo (&lt;90%)-and hypermetabolism. (&gt;110%). Bland-Altman method and two-way mixed intraclass correlation coefficients (ICC) (single measures) were used to assess the agreement between mREE and pREE. Results: Indirect calorimetric measurements were performed in 180 of the 432 admitted patients (42%). Of the 276 performed measurements 85% were valid, and of these 90% were used to tailor nutritional therapy. Most patients were male (71%), median age was 62 years [IQR 52; 70]. Logistical issues (absence of measuring staff, no device, no stock of disposables, MRSA isolation) and clinical issues (e.g Fio2&gt;70%, detubated but still in ICU) were the main reasons for not performing indirect calorimetry. The majority of the REE-measurements indicated either hypo- or hypermetabolism (57% week 1 and 56% week 2). The correlation between mREE and pREE was very moderate (ICC = 0.527). Conclusions: Although indirect calorimetry was performed in less than half of the patients, it proved to be of value to guide nutritional therapy. We conclude that the technique is easily applicable and expect that its impact can be significantly increased with the resolution of logistical and organizational issues.</p

An evaluation of the IDEEA™ activity monitor for estimating energy expenditure

Peer reviewedPublisher PD

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