Describing Energy Expenditure in Children with a Chronic Disease: A Systematic Review.

Understanding energy expenditure in children with chronic disease is critical due to the impact on energy homeostasis and growth. This systematic review aimed to describe available literature of resting (REE) and total energy expenditure (TEE) in children with chronic disease measured by gold-standard methods of indirect calorimetry (IC) and doubly labeled water (DLW), respectively. A literature search was conducted using OVID Medline, Embase, CINAHL Plus, Cochrane, and Scopus until July 2023. Studies were included if the mean age of the participants was ≤18 y, participants had a chronic disease, and measurement of REE or TEE was conducted using IC or DLW, respectively. Studies investigating energy expenditure in premature infants, patients with acute illness, and intensive care patients were excluded. The primary outcomes were the type of data (REE, TEE) obtained and REE/TEE stratified by disease group. In total, 271 studies across 24 chronic conditions were identified. Over 60% of retrieved studies were published >10 y ago and conducted on relatively small population sizes (n range = 1-398). Most studies obtained REE samples (82%) rather than that of TEE (8%), with very few exploring both samples (10%). There was variability in the difference in energy expenditure in children with chronic disease compared with that of healthy control group across and within disease groups. Eighteen predictive energy equations were generated across the included studies. Quality assessment of the studies identified poor reporting of energy expenditure protocols, which may limit the validity of results. Current literature on energy expenditure in children with chronic disease, although extensive, reveals key future research opportunities. International collaboration and robust measurement of energy expenditure should be conducted to generate meaningful predictive energy equations to provide updated evidence that is reflective of emerging disease-modifying therapies. This study was registered in PROSPERO as CRD42020204690.

Measurement and estimation of energy in the critically ill.

PURPOSE OF REVIEW: Recent changes in guidelines recommendation during early phase of critical illness and use of indirect calorimetry. The aim of this review is to discuss methods of determining energy requirements in the critically ill and highlight factors impacting resting energy expenditure. RECENT FINDING: An appraisal of recent literature discussing indirect calorimetry guided-nutrition potential benefits or pitfalls. Recent attempts to devise strategy and pilot indirect calorimetry use in the critically ill patients requiring continuous renal replacement therapy or extracorporeal membrane oxygenation are also discussed. Additionally, we briefly touched on variability between guidelines recommended energy target and measured energy expenditure for adult critically ill patients with obesity. SUMMARY: While energy requirement in the critically ill continues to be an area of controversy, recent guidelines recommendations shift toward providing less aggressive calories during acute phase of illness in the first week of ICU.Use of indirect calorimetry may provide more accurate energy target compared to the use of predictive equations. Despite the absence of literature to support long term mortality benefits, there are many potential benefits for the use of indirect calorimetry when available.

Determination of energy requirements after minor burns using indirect calorimetry: A descriptive cohort study.

BACKGROUND: Minor burns could be associated with moderate hypermetabolism. In this study, the primary outcome was measured energy expenditure (mEE) determined by indirect calorimetry in patients with minor burns. We also compared mEE with predictive values and actual energy intakes. METHODS: Adults with minor burns exclusively treated on an outpatient basis were included. During the week following injury, a dietitian performed indirect calorimetry (Q-NRG in canopy mode), calculated the estimated energy expenditure (eEE) based on the Harris-Benedict (HB) and Henry formulas, and evaluated daily energy intakes using a food anamnesis. RESULTS: Forty-nine patients (59.2% male; median age: 35 [interquartile range: 29-46.5] years; body mass index [BMI]: 26.2 [22.3-29.6] kg/m2; burn surface area [BSA]: 1.5% [1%-2%]) were included 4 (2-6) days after injury. The mEE was 1863 (1568-2199) kcal or 25 (22.4-28.5) kcal/kg and 1838 (1686-2026) kcal or 26.1 (23.7-27.7) kcal/kg in patients who were respectively fasting for >10 h or not (P = 0.991 or P = 0.805). The total mEE was 104% (95%-116%) and 108% (99%-122%) of the total eEE using the HB and Henry formulas, respectively, with diet-induced thermogenesis and physical activity level. Hypermetabolism (ie, oxygen consumption at rest ≥3.5 ml/kg/min) was observed in 21/49 (42.9%) patients. Energy intakes corresponded to 71% (60%-86%) of the total mEE. CONCLUSION: Performing indirect calorimetry in adults with minor burns revealed that ≥40% of the tested adults presented a hypermetabolism and that their mEE was not covered by their energy intakes.

Estimates of resting energy expenditure using predictive equations in adults with severe burns: A systematic review and meta-analysis.

BACKGROUND: Many equations to estimate the resting energy expenditure (REE) of patients with burns are currently available, but which of them provides the best guide to optimize nutrition support is controversial. This review examined the bias and precision of commonly used equations in patients with severe burns. METHODS: A systematic search of the PubMed, Web of Science, Embase, and Cochrane Library databases was undertaken on June 1, 2023, to identify studies comparing predicted REE (using equations) with measured REE (by indirect calorimetry [IC]) in adults with severe burns. Meta-analyses of bias and calculations of precisions were performed in each predictive equation, respectively. RESULTS: Nine eligible studies and 12 eligible equations were included. Among the equations, the Toronto equation had the lowest bias (26.1 kcal/day; 95% CI, -417.0 to 469.2), followed by the Harris-Benedict equation × 1.5 (1.5HB) and the Milner equation. The Ireton-Jones equation (303.4 kcal/day; 95% CI, 224.5-382.3) acceptably overestimated the REE. The accuracy of all of the equations was <50%. The Ireton-Jones equation had the relatively highest precision (41.2%), followed by the 1.5HB equation (37.0%) and the Toronto equation (34.7%). CONCLUSION: For adult patients with severe burns, all of the commonly used equations for the prediction of REE are inaccurate. It is recommended to use IC for accurate REE measurements and to use the Toronto equation, 1.5HB equation, or Ireton-Jones equation as a reference when IC is not available. Further studies are needed to propose more accurate REE predictive models.

Research Note: Effect of fasting time on the fasting heat production, blood metabolites, and body components of layer-type pullets.

Fasting heat production (FHP) is used to assess the maintenance net energy requirement of animals. Herein, the FHP of layer-type pullets was estimated. In trial 1, 16 40-day-old Jingfen layer-type pullets were divided into 4 groups of 4 chickens and placed in 4 respiratory chambers. Pullets had free access to feed and water. After 4-d acclimatization, feed was withdrawn, and chickens were measured for FHP for 3 consecutive days. In trial 2, twenty-four 40-day-old pullets were placed in 4 respiratory calorimetry chambers, with 6 pullets per chamber. After 4-d acclimatization, one chamber was randomly selected and all pullets in the chamber was sampled at 5, 25, 50, or 65 h after feed withdrawal. The result showed that FHP declined with fasting time and reached the lowest level between 48 and 72 h. Respiratory quotient was decreased (P < 0.05) between 24 and 48 h compared with that in the first 24 h after fasting. The FHP in the light period showed a significant to decline with fasting time (P < 0.01), whereas the FHP in the dark period was decreased (P < 0.01) 24 h after fasting. Body weight, thigh mass, and abdominal fat decreased (P < 0.05) at 25 h after fasting. Serum glucose were increased (P < 0.01) and while triglycerides were significantly decreased (P < 0.01) at 50 h compared with that at 5 and 25 h time point. The result suggests that the adequate measuring period for FHP for layer-type pullets is from 24 to 48 h after fasting. The FHP of 7-wk-old layer-type pullets was 562.20 kJ/kg of BW0.75/d under a 10-h light and 14-h dark lighting regime.

Low respiratory quotient correlates with high mortality in patients undergoing mechanical ventilation.

OBJECTIVE: Oxygen consumption (VO2), carbon dioxide generation (VCO2), and respiratory quotient (RQ), which is the ratio of VO2 to VCO2, are critical indicators of human metabolism. To seek a link between the patient's metabolism and pathophysiology of critical illness, we investigated the correlation of these values with mortality in critical care patients. METHODS: This was a prospective, observational study conducted at a suburban, quaternary care teaching hospital. Age 18 years or older healthy volunteers and patients who underwent mechanical ventilation were enrolled. A high-fidelity automation device, which accuracy is equivalent to the gold standard Douglas Bag technique, was used to measure VO2, VCO2, and RQ at a wide range of fraction of inspired oxygen (FIO2). RESULTS: We included a total of 21 subjects including 8 post-cardiothoracic surgery patients, 7 intensive care patients, 3 patients from the emergency room, and 3 healthy volunteers. This study included 10 critical care patients, whose metabolic measurements were performed in the ER and ICU, and 6 died. VO2, VCO2, and RQ of survivors were 282 +/- 95 mL/min, 202 +/- 81 mL/min, and 0.70 +/- 0.10, and those of non-survivors were 240 +/- 87 mL/min, 140 +/- 66 mL/min, and 0.57 +/- 0.08 (p = 0.34, p = 0.10, and p < 0.01), respectively. The difference of RQ was statistically significant (p < 0.01) and it remained significant when the subjects with FIO2 < 0.5 were excluded (p < 0.05). CONCLUSIONS: Low RQ correlated with high mortality, which may potentially indicate a decompensation of the oxygen metabolism in critically ill patients.

Indirect Calorimetry-Based Novel Approach for Evaluating Metabolic Flexibility and Its Association with Circulating Metabolic Markers in Middle-Aged Subjects.

We propose a novel method for assessing metabolic flexibility (MF) through indirect calorimetry. A total of twenty healthy volunteers (10 females; 10 males) aged 45-65 were categorized into a Low-Intensity activity group (LI, 0-1 session of 1 h per week) and a High-Intensity activity group (HI, 5-6 sessions of 2 h per week). Volunteers underwent a stepwise exercise test on a cycle ergometer, connected to a calorimeter, to examine respiratory gas exchange to evaluate peak fatty acid Oxidation (PFO) and peak carbohydrate oxidation (PCO). Circulating peroxisome proliferator-activated receptor α (PPARα) biomarkers, docosahexaenoic acid/eicosapentaenoic acid (DHA/EPA) ratio and N-oleoylethanolamine (OEA), and the endocannabinoid- 2-arachidonoylglycerol (2-AG), were evaluated. We developed two MF parameters: the MF index (MFI), calculated by the product of PFO normalized per kg of fat-free mass (FFM) and the percentage of VO2max at PFO, and the peak energy substrates' oxidation (PESO), computed by summing the kilocalories from the PFO and PCO, normalized per kg FFM. The MFI and PESO were significantly different between the HI and LI groups, showing strong correlations with the circulating bioactive substances. Higher DHA/EPA ratio (p ≤ 0.05) and OEA (p ≤ 0.01), but lower 2-AG levels (p ≤ 0.01) were found in the HI group. These new parameters successfully established a functional link between MF and the balance of PPARα/endocannabinoid systems.

Basal metabolic rate using indirect calorimetry among individuals living with overweight or obesity: The accuracy of predictive equations for basal metabolic rate.

BACKGROUND & AIMS: Weight reduction programs in people with overweight or obesity can be informed by indirect calorimetry (IC) which is the gold standard to measure basal metabolic rate (BMR). Since IC is labor intensive and expensive, predictive equations are often used as an alternative. In this study the accuracy rate was assessed and bias statistics of predictive equations were compared to IC among subjects with overweight or obesity. Secondly, differences in clinical features between individuals with over-, accurate or underestimation of their BMR were evaluated. METHODS: This cross sectional study included 731 subjects from the outpatient obesity clinic of the Antwerp University Hospital, Belgium. Fourteen equations were evaluated. Overestimation and underestimation was defined as >10 % and <10 % of measured BMR. RESULTS: In the total population, mean age was 43 ± 13 years, mean BMI 35.6 ± 5.8 kg/m2 and 79.5 % were female. The highest accuracy rates were reached by the Henry (73 %), Ravussin (73 %) and Mifflin St. Jeor (73 %) equations. In the total population, the Mifflin St. Jeor and Henry equation were unbiased. The Akern, Livingston and Ravussin equations were biased to underestimation. All other equations were biased to overestimation. Subjects with an underestimation of BMR had significantly higher waist-hip ratio (1.02 ± 0.13 vs 0.91 ± 0.11; P < 0.001), higher visceral adipose tissue (239 ± 96 vs 162 ± 93; P < 0.001), lower fat free mass (kg) (67.6 (45.4-95.9) vs 54.0 (39.6-95.5); P < 0.001) and a higher prevalence of the Metabolic Syndrome (24 (77.4) vs 112 (37.5); P < 0.001). Individuals with an overestimation of BMR had significantly higher subcutaneous adipose tissue (545 ± 149 vs 612 ± 149; P < 0.05), lower fasting plasma insulin (81 (10-2019) vs 67 (27-253); P < 0.001) and lower 2-h plasma glucose (132 (30-430) vs 116 (43-193); P < 0.001) during OGTT. CONCLUSIONS: In this study, the Henry and Mifflin St. Jeor equations have the highest accuracy and lowest bias to estimate the basal metabolic rate in a Caucasian, predominantly female, population living with overweight or obesity. Visceral and subcutaneous adipose tissue and presence of metabolic syndrome were significantly different in individuals with over- or underestimation of BMR.

An evaluation of intensive care nurses' performance of indirect calorimetry measurements.

BACKGROUND: Indirect calorimetry (IC) is the gold standard to monitor energy expenditure in critically ill patients. In several intensive care units (ICUs), nurses are responsible for carrying out the measurements. AIM: The aim of this study was to assess nurses' perception of their involvement in IC. STUDY DESIGN: This was a prospective survey conducted in the surgical ICU of a French university hospital after 18 months of use of the Q-NRG + ® calorimeter (COSMED©, Italy). All nurses who have used the calorimeter in the previous 6 months in this ICU were questioned through a questionnaire about their theoretical and practical knowledge and experience in using it. RESULTS: The participation rate was 93% (28/30 surveyed). All the respondents understood the objectives of performing an IC and 23 of them (82%) had used the device at least once in the previous 6 months. All the users thought it was pertinent that ICU nurses were in charge of the IC measurements, 16 of them (70%) reported having been formally trained, mostly by a colleague, and 17 (77%) felt comfortable with the device after 2 to 5 uses. The five non-users (8%) did not have the opportunity to do so. Theoretical and practical knowledge could be improved as only 5 of the users (22%) declared to know the main criteria of reliability of the IC measurement and 4 of them (18%) declared to know the maintenance and cleaning protocol of the device. CONCLUSION: Nurses quickly felt comfortable with the Q-NRG + ® in this ICU. Formal initial and ongoing training of all staff completing IC is essential to perform IC measurements safely and to obtain reliable and interpretable results in practice. RELEVANCE TO CLINICAL PRACTICE: Involving the nursing team in nutritional care, even if it is technical, seems to bring satisfaction in terms of overall patient care.

Validation of Indirect Calorimetry in Children Undergoing Single-Limb Non-Invasive Ventilation: A Proof of Concept, Cross-Over Study.

BACKGROUND: The accurate assessment of resting energy expenditure (REE) is essential for personalized nutrition, particularly in critically ill children. Indirect calorimetry (IC) is the gold standard for measuring REE. This methodology is based on the measurement of oxygen consumption (VO2) and carbon dioxide production (VCO2). These parameters are integrated into the Weir equation to calculate REE. Additionally, IC facilitates the determination of the respiratory quotient (RQ), offering valuable insights into a patient's carbohydrate and lipid consumption. IC validation is limited to spontaneously breathing and mechanically ventilated patients, but it is not validated in patients undergoing non-invasive ventilation (NIV). This study investigates the application of IC during NIV-CPAP (continuous positive airway pressure) and NIV-PS (pressure support). METHODS: This study was conducted in the Pediatric Intensive Care Unit of IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, between 2019 and 2021. Children < 6 years weaning from NIV were enrolled. IC was performed during spontaneous breathing (SB), NIV-CPAP, and NIV-PS in each patient. A Bland-Altman analysis was employed to compare REE, VO2, VCO2, and RQ measured by IC. RESULTS: Fourteen patients (median age 7 (4; 18) months, median weight 7.7 (5.5; 9.7) kg) were enrolled. The REE, VO2, VCO2, and RQ did not differ significantly between the groups. The Limits of Agreement (LoA) and bias of REE indicated good agreement between SB and NIV-CPAP (LoA +28.2, -19.4 kcal/kg/day; bias +4.4 kcal/kg/day), and between SB and NIV-PS (LoA -22.2, +23.1 kcal/kg/day; bias 0.4 kcal/kg/day). CONCLUSIONS: These preliminary findings support the accuracy of IC in children undergoing NIV. Further validation in a larger cohort is warranted.

The Development of a Resting Metabolic Rate Prediction Equation for Professional Male Rugby Union Players.

Determining resting metabolic rate (RMR) is an important aspect when calculating energy requirements for professional rugby union players. Prediction equations are often used for convenience to estimate RMR. However, the accuracy of current prediction equations for professional rugby union players remains unclear. The aims of this study were to examine the RMR of professional male rugby union players compared to nine commonly used prediction equations and develop and validate RMR prediction equations specific to professional male rugby union players. One hundred and eight players (body mass (BM) = 102.9 ± 13.3 kg; fat-free mass (FFM) = 84.8 ± 10.2 kg) undertook Dual-energy X-ray Absorptiometry scans to assess body composition and indirect calorimetry to determine RMR. Mean RMR values of 2585 ± 176 kcal∙day-1 were observed among the group with forwards (2706 ± 94 kcal·day-1), demonstrating significantly (p < 0.01; d = 1.93) higher RMR compared to backs (2465 ± 156 kcal·day-1), which appeared to be due to their higher BM and FFM measures. Compared to the measured RMR for the group, seven of the nine commonly used prediction equations significantly (p < 0.05) under-estimated RMR (-104-346 kcal·day-1), and one equation significantly (p < 0.01) over-estimated RMR (192 kcal·day-1). This led to the development of a new prediction equation using stepwise linear regression, which determined that the strongest predictor of RMR for this group was FFM alone (R2 = 0.70; SEE = 96.65), followed by BM alone (R2 = 0.65; SEE = 104.97). Measuring RMR within a group of professional male rugby union players is important, as current prediction equations may under- or over-estimate RMR. If direct measures of RMR cannot be obtained, we propose the newly developed prediction equations be used to estimate RMR within professional male rugby union players. Otherwise, developing team- and/or group-specific prediction equations is encouraged.

Variation in metabolic demand following severe pediatric traumatic brain injury: A case review.

A traumatic brain injury (TBI) is one of the most common pediatric traumas among children in the United States. Appropriate nutrition support, including the initiation of early enteral nutrition, within the first 48 h after injury is crucial for children with a TBI. It is important that clinicians avoid both underfeeding and overfeeding, as both can lead to poor outcomes. However, the variable metabolic response to a TBI can make determining appropriate nutrition support difficult. Because of the dynamic metabolic demand, indirect calorimetry (IC) is recommended, instead of predictive equations, to measure energy requirements. Although IC is suggested and ideal, few hospitals have the technology available. This case review discusses the variable metabolic response, identified using IC, in a child with a severe TBI. The case report highlights the ability of the team to meet measured energy requirements early, even in the setting of fluid overload. It also highlights the presumed positive impact of early and appropriate nutrition provision on the patient's clinical and functional recovery. Further research is needed to investigate the metabolic response to TBIs in children and the impact optimal feedings based on the measured resting energy expenditure have on clinical, functional, and rehabilitation outcomes.

Association between energy surplus and intensive care unit length of stay in critically ill patients: A retrospective cohort study.

BACKGROUND: Patients experiencing persistent critical illness have poor short-term and long-term outcomes and consume disproportionate amounts of health care resources. Nutrition optimization may improve outcomes, though few data exist on resting energy expenditure and nutrition requirements. We hypothesized that increased energy surplus per day is associated with increased intensive care unit (ICU) length of stay (LoS) in critically ill patients. METHODS: Patients from a single ICU at Royal London Hospital were included in this retrospective cohort study. EXPOSURE: energy surplus measured by serial indirect calorimetry (IC) and nutrition intake. INCLUSION CRITERIA: mechanical ventilation of ≥3 days and expected to remain ventilated. PRIMARY OUTCOME: ICU LoS. RESULTS: Across 30 patients (median LoS 21 days), increased ICU LoS was associated with actual daily energy intake surplus to resting energy expenditure (REE) (R2 0.16; P < 0.005). Median REE was less than predicted energy requirements: 24 kcal per day per kilogram of ideal body weight (IBW) (interquartile range [IQR], 20-28) vs 28 kcal/day/kg IBW (IQR, 26-29) (P < 0.001). Patients with COVID-19 had a median energy surplus (actual intake- REE) + 344 kcal/day (IQR 35-517) vs -57 kcal/day (IQR -324 to 211) in other patients (P = 0.011); however, they had a median LoS of 44 days (IQR 26-58) vs 10 days (IQR 7-24), respectively (P < 0.001). Patients with obesity had a median energy deficit of -32 kcal/day (IQR -384 to 335) vs +234 kcal/day (IQR -79 to 499) for nonobese patients (P = 0.021). CONCLUSION: Overfeeding represents an easily modifiable factor to improve outcomes in patients experiencing persistent critical illness, for which IC may be useful.

Comparison of pre- and posttransplant energy expenditure in patients undergoing hematopoietic stem cell transplantation and evaluation of associated factors.

OBJECTIVES: Patients undergoing hematopoietic stem cell transplantation may present with metabolic alterations that can have an effect on their energy expenditure and nutritional status. This project aimed to compare the pre- and posttransplant energy expenditures of patients undergoing hematopoietic stem cell transplantation as well as related factors. METHODS: This prospective study was conducted at a single center. Patients, undergoing autograft or allograft, were evaluated before transplantation and on the 10th and 17th d posttransplantation. Energy expenditure was measured by indirect calorimetry. Diet intake was assessed by a 24-h dietary recall. Infectious and noninfectious complications were analyzed between days 1 to 10 after transplantation and days 11 to 17 after transplantation. Paired model analyses were carried out to identify the pretransplantation and posttransplantation periods. RESULTS: Twenty patients were evaluated with a mean age of 45.6 ± 17.2 y; a majority were male sex (65%), and the most frequent diagnoses were chronic myeloid leukemia (25%) and multiple myeloma (25%). Energy expenditure increased by 15% posttransplantation, and the energy requirement per kilogram of weight was 23 kcal/kg at day 10 after transplantation. Throughout the posttransplantation period, 45% of the patients required nutritional therapy. Negative energy and negative protein balance were observed at all analyzed times. Phase angle (P = 0.018), fever (P = 0.014), mucositis grades I to II (P = 0.018), and the total number of infectious and noninfectious events (P = 0.043) were associated with an increase in energy expenditure at day 10 after transplantation. CONCLUSIONS: Energy expenditure increased after transplantation compared with pretransplantation in 50% of patients. Phase angle, fever, grades I to II mucositis, and infectious and noninfectious events were associated with increased energy expenditure at day 10 after transplantation.

Excess Postexercise Oxygen Consumption Following Isocaloric Bouts of Resistance and Aerobic Exercise in Older Adults.

Purpose: Albeit being a major determinant of exercise-related energy expenditure (EE), there is a lack of research on the excess post-exercise oxygen consumption (EPOC) after different exercise modalities in older adults. This study compared the EPOC after isocaloric bouts of resistance (RE) and aerobic (AE) exercise. Methods: The EE during exercise was determined through telemetric indirect calorimetry in ten physically active participants aged 63 to 82 years (5 women, 73 ± 6 years, 70.5 ± 9.9 kg, 161 ± 8 cm). The target EE in AE corresponded to values achieved during RE, and the EPOC was assessed for 30 min in the supine position. Results: The EE during AE and RE were 126.0 ± 30.7 kcal and 123.9 ± 30.6 kcal, respectively. The time to achieve the target EE was 2.3 times shorter in AE vs. RE. The EPOC magnitude was greater after AE (7.9 ± 2.4 L, 40.1 ± 11.1 kcal) than RE (5.9 ± 1.8 L, 26.9 ± 11.5 kcal). Conclusion: Older adults showed greater EPOC after isocaloric sessions of AE vs. RE. Additionally, AE had better temporal efficiency than RE to elicit a given EE.

Influence of the time of day in the effect of caffeine on maximal fat oxidation during exercise in women: a randomized, crossover, double-blind, and placebo-controlled study.

PURPOSE: Caffeine is a stimulant with well-recognized performance and metabolic benefits, however, there is a lack of studies investigating the time-of-day influence in the properties of caffeine to enhance fat oxidation in women. Thus, the aim of the present study was to evaluate the influence of the time of the day on the effect of caffeine on the maximal rate of fat oxidation during aerobic exercise in trained women. METHODS: Fourteen female athletes (25.5 ± 7.1 years) took part in a randomized, crossover, double-blind study. All participants undertook four different experimental trials combining the ingestion of 3 mg/kg caffeine and a placebo either in the morning (8.00-10.00 h) and in the evening (17.00-19.00 h) realizing an incremental test on a cycle ergometer with 3 min stages at workloads from 30 to 70% of maximal oxygen uptake (VO2max). Substrate oxidation rates were measured by indirect calorimetry. In each trial, the maximum rate of fat oxidation (MFO) and the intensity that elicited MFO (Fatmax) were measured. RESULTS: In comparison to placebo, MFO was significantly higher with caffeine both in the morning (0.24 ± 0.13 vs 0.30 ± 0.14 g/min; p < 0.001; ES = 0.79) and in the evening (0.21 ± 0.08 vs 0.28 ± 0.10 g/min; p = 0.002; ES = 0.72). No time-of-day effect on the capacity of caffeine to increase MFO was found (all p = 0.336) CONCLUSION: The intake of 3 mg/kg of caffeine increased the use of fat as a fuel during exercise independently of the time-of-day in trained women. TRIAL REGISTRATION: The study was registered in ClinicalTrials.gov with the following ID: NCT05880186 by 15 May 2023.

Effect of influenza vaccination on resting metabolic rate and c-reactive protein concentrations in healthy young adults.

OBJECTIVES: Chronic immune activation and severe inflammatory states are positively associated with resting metabolic rate (RMR; kcal/day), but the impacts of mild immune stimuli on metabolism are poorly understood. This study investigates the within-individual association between the inflammatory response to influenza vaccination and RMR in young adults. METHODS: We evaluated RMRs through indirect calorimetry and circulating c-reactive protein (CRP) concentrations (mg/L)-a direct measure of inflammation-via high-sensitivity immunoassays of dried blood spots (n = 17) at baseline and two- and seven-days post-vaccine. Wilcoxon matched-pairs signed-rank tests were used to evaluate the magnitude of the CRP and RMR responses. Type II Wald chi-square tests of linear mixed-effect models assessed whether those responses were correlated. RESULTS: Baseline CRP was 1.39 ± 1.26 mg/L. On day two post-vaccine, CRP increased by 1.47 ± 1.37 mg/L (p < 0.0001), representing a 106% increase above baseline values. CRP remained higher on day seven post-vaccine, 1.32 ± 2.47 mg/L (p = 0.05) above baseline values. There were no statistically significant changes in RMR from baseline to day two (p = 0.98) or day seven (p = 0.21). Change in CRP from baseline did not predict RMR variation across days (p = 0.46). CONCLUSIONS: We find no evidence that adult influenza vaccination results in a corresponding increase in RMR. These results suggest that the energetic cost of an influenza vaccine's mild inflammatory stimulus is either too small to detect or is largely compensated by a temporary downregulation of energy allocated to other metabolic tasks.

Comparison of energy expenditure measurements by a new basic respiratory room vs. classical ventilated hood.

BACKGROUND: Nutritional support is often based on predicted resting energy expenditure (REE). In patients, predictions seem invalid. Indirect calorimetry is the gold standard for measuring EE. For assessments over longer periods (up to days), room calorimeters are used. Their design makes their use cumbersome, and warrants improvements to increase utility. Current study aims to compare data on momentary EE, obtained by a basic respiration room vs. classical ventilated hood. The objective is to compare results of the basic room and to determine its 1)reliability for measuring EE and 2)sensitivity for minute changes in activity. METHODS: Two protocols (P1; P2)(n = 62; 25 men/37 women) were applied. When measured by hood, participants in both protocols were in complete rest (supine position). When assessed by room, participants in P1 were instructed to stay half-seated while performing light desk work; in P2 participants were in complete rest mimicking hood conditions. The Omnical calorimeter operated both modalities. Following data were collected/calculated: Oxygen uptake ([Formula: see text] O2(ml/min)), carbon dioxide production ([Formula: see text] CO2ml/min), 24h_EE (kcal/min), and respiratory exchange ratio (RER). Statistical analyses were done between modalities and between protocols. The agreement between 24h_EE, [Formula: see text] O2 and [Formula: see text] CO2 obtained by both modalities was investigated by linear regression. Reliability analysis on 24h_EE determined ICC. RESULTS: No significant differences were found for 24h_EE and [Formula: see text] O2. [Formula: see text] CO2 significantly differed in P1 + P2, and P2 (hood > room). RER was significantly different (hood > room) for P1 + P2 and both protocols individually. Reliability of 24h_EE between modalities was high. Modality-specific results were not different between protocols. DISCUSSION/CONCLUSION: The room is valid for assessing momentary EE. Minute changes in activity lead to a non-significant increase in EE and significant increase in RER. The significant difference in [Formula: see text] CO2 for hood might be related to perceived comfort. More research is necessary on determinants of RER, type (intensity) of activity, and restlessness. The design of the room facilitates metabolic measurements in research, with promising results for future clinical use.

Redefining Nutritional Requirements in End-Stage Liver Disease: Towards a Personalized Approach.

Malnutrition is ubiquitous in cirrhotic patients presenting for liver transplant (LT). Providing an appropriate energy prescription is fundamental to effective nutrition therapy. We aimed to compare measured energy expenditure (mEE) with predicted energy expenditure (pEE) in patients awaiting LT and determine clinical factors associated with mEE. In this prospective observational study, energy expenditure was measured by indirect calorimetry in 110 adult patients referred for LT and predicted by commonly utilized equations (Harris-Benedict, Schofield, and EASL guidelines). Nutritional status, anthropometry, muscle function, biochemical and clinical data were also collected. The median model for end-stage liver disease (MELD) was 19 (IQR 13, 25), and the majority were Child-Pugh B (51%) or C (37%). Malnutrition was evident in 85%. Median mEE by calorimetry was 1756 (1531, 2104) kcal/d and significantly higher than pEE as per Harris-Benedict 1480 (1322, 1722) kcal/d and Schofield 1474 (1349, 1723) kcal/d (both p < 0.001), but lower than EASL guidelines (35 kcal/kg) when an activity factor was applied to mEE; 2283 (1990, 2735) kcal/d versus 2590 (2178, 3010) kcal/d (p < 0.001). Hypermetabolism (mEE:pEE > 1.2) was evident in 48% of the cohort. Multivariate analysis found MELD, Child-Pugh class, diuretic use, and severe malnutrition to be independent predictors of hypermetabolism. A new liver-specific predictive model has been developed, showing superior agreement with mEE than common predictive equations. In conclusion, there is a poor correlation between mEE and pEE in patients awaiting LTs, and hypermetabolism is common. Relying on historical predictive equations in this patient population may result in significant under or over-feeding. A tailored energy prescription based on indirect calorimetry or a liver-specific predictive model is recommended for LT candidates.

[Correlation of equations for energy expenditure with indirect calorimetry in critically ill patients]. / Correlación de fórmulas para gasto energético con calorimetría indirecta en pacientes críticos.

Background: Nutrition in the Intensive Care Unit (ICU) is a cornerstone; however, energy requirements are a controversial issue that has not yet been resolved. Calorimetry is the gold standard for calculating energy expenditure, but it is expensive and not available in all ICU areas. Formulas have been developed to calculate basal energy expenditure (BAE) and make the process easier. Objective: To validate the predictive formulas of BAE compared to that obtained with ventilatory indirect calorimetry (IC) within the nutritional assessment in ICU patients. Material and methods: Analytical cross-sectional retrolective study. We performed BAE measurement on patients in the ICU of a third level hospital with ventilatory indirect calorimetry and compared the results obtained with those of the Harris Benedict, Muffin-St. Jeor, Institute of Medicine, and Faisy equations. Results: A total of 49 patients were included; a moderate correlation with statistical significance was found between the BAE measurements obtained by indirect calorimetry, with those obtained by four predictive equations that were studied. The Faisy equation obtained the strongest correction with r = 0.461 (p = 0.001). Conclusion: The correlation between the BAE obtained by predictive equations and by IC goes from mild to moderate, due to the heterogeneity of critical patients and their changing nature throughout their disease.

Introducción: la nutrición en la unidad de cuidados intensivos (UCI) es una piedra angular; sin embargo, los requerimientos energéticos son un tema controversial aún no resuelto. La calorimetría es el estándar de oro para calcular el gasto energético, pero es costosa y no está disponible en todas las áreas de las UCI. Se han desarrollado fórmulas para calcular el gasto energético basal (GEB) y hacer el proceso más sencillo. Objetivo: validar las fórmulas predictivas de GEB comparado con el obtenido con calorimetría indirecta (CI) ventilatoria dentro de la valoración nutricia en los pacientes de UCI. Material y métodos: estudio transversal analítico retrolectivo. Realizamos medición de GEB a los pacientes de la UCI de un hospital de tercer nivel con calorimetría indirecta ventilatoria y se compararon los resultados obtenidos con los de las fórmulas de Harris Benedict, Muffin-St. Jeor, Institute of Medicine y Faisy. Resultados: se incluyeron un total de 49 pacientes; se encontró correlación moderada con significación estadística entre las medidas de GEB obtenidas por calorimetría indirecta, con las obtenidas por cuatro fórmulas predictivas que se estudiaron. La fórmula de Faisy obtuvo la corrección más fuerte con una r = 0.461 (p = 0.001). Conclusión: la correlación entre el GEB obtenido por fórmulas predictivas y por CI es de ligera a moderada, debido a la heterogeneidad del paciente crítico y su naturaleza cambiante a lo largo de su enfermedad.