Obesity and critical care nutrition: current practice gaps and directions for future research

How to interpret and apply the results of indirect calorimetry studies: A case-based tutorial

Evidence is growing that the individual adjustment of energy targets guided by indirect calorimetry (IC) can improve outcome. With the development of a new generation of devices that are easier to use and rapid, it appears important to share knowledge and expertise that may be used to individualize nutrition care. Despite the focus of this tutorial being on one contemporary device, the principles of IC apply across existing devices and can assist tailoring the nutrition prescription and in assessing response to nutrition therapy. The present tutorial addresses its clinical application in intubated mechanically ventilated and spontaneously breathing adult patients (canopy), i.e. it covers the range from critical illness to outpatients. The cases that are presented show how the measured energy expenditure (mEE), and the respiratory quotient (RQ), i.e. the ratio of expired CO2 to consumed O2, should be applied in different cases, to adapt and individualize nutrition prescription, as it is a good marker of over- or underfeeding at the different stages of disease. The RQ also informs about the patient's body's capacity to use different substrates: the variations of RQ indicating the metabolic changes revealing insufficient or excessive feeding. The different cases reflect the use of a new generation device as a metabolic monitor that should be combined with other clinical observations and laboratory biomarkers. The tutorial also points to some shortcomings of the method, proposing alternatives.

Dietary protein in the ICU in relation to health outcomes

PURPOSE OF REVIEW

Critical care nutrition guidelines recommend provision of higher protein doses than recommended in health. These recommendations have been predominately based on lower quality evidence and physiological rationale that greater protein doses may attenuate the significant muscle loss observed in critically ill patients. This review discusses the mechanistic action of protein in the critically ill, details results from recent trials on health outcomes, discusses considerations for interpretation of trial results, and provides an overview of future directions.

RECENT FINDINGS

Two recent large clinical trials have investigated different protein doses and the effect on clinical outcome. Important findings revealed potential harm in certain sub-groups of patients. This harm must be balanced with the potential for beneficial effects on muscle mass and physical function given that two recent systematic reviews with meta-analyses demonstrated attenuation of muscle loss with higher protein doses. Utilizing biological markers such as urea: creatinine ratio or urea levels may prove useful in monitoring harm from higher protein doses.

SUMMARY

Future research should focus on prospectively investigating biological signatures of harm as well as taking into the consideration elements that will likely enhance the effectiveness of protein dose.

Joint effect of atrial fibrillation and obesity on mortality in critically ill patients

BACKGROUND

The interplay between atrial fibrillation (AF) and obesity on mortality in critically ill patients warrants detailed exploration, given their individual impacts on patient prognosis. This study aimed to assess the associations between AF, obesity, and 1-year mortality in a critically ill population.

METHODS

Utilizing data from the Medical Information Mart for Intensive Care (MIMIC)-IV database, we conducted a retrospective analysis of adult patients admitted to the intensive care unit. The primary endpoint was 1-year mortality, analyzed through Cox regression with hazard ratio (HR) and Kaplan-Meier survival methods.

RESULTS

The study included 25,654 patients (median age 67.0 years, 40.6% female), with 39.0% having AF and 36.1% being obese. Multivariate COX regression analysis revealed that AF was associated with a 14.7% increase in the risk of 1-year mortality (p < 0.001), while obesity was linked to a 13.9% reduction in mortality risk (p < 0.001). The protective effect of obesity on mortality was similar in patients with (HR = 0.85) and without AF (HR = 0.86). AF led to a slightly higher risk of mortality in patients without obesity (HR = 1.16) compared to those with obesity (HR = 1.13). Kaplan-Meier survival curves highlighted that non-obese patients with AF had the lowest survival rate, whereas the highest survival was observed in obese patients without AF.

CONCLUSIONS

AF significantly increased 1-year mortality risk in critically ill patients, whereas obesity was associated with a decreased mortality risk. The most adverse survival outcomes were identified in non-obese patients with AF.

Smartfeeding: A Dynamic Strategy to Increase Nutritional Efficiency in Critically Ill Patients-Positioning Document of the Metabolism and Nutrition Working Group and the Early Mobilization Working Group of the Catalan Society of Intensive and Critical Care Medicine (SOCMiC)

Adequate medical nutrition therapy for critically ill patients has an impact on their prognoses. However, it requires an individualized approach that takes into account the activity (phases of metabolic stress) and particularity of these patients. We propose a comprehensive strategy considering the patients' nutritional status and the set of modifiable circumstances in these patients, in order to optimize/support nutritional efficiency: (1) A detailed anamnesis and an adequate initial nutritional assessment must be performed in order to implement medical nutrition therapy that is in line with the needs and characteristics of each patient. Furthermore, risks associated with refeeding syndrome, nutritrauma or gastrointestinal dysfunction must be considered and prevented. (2) A safe transition between nutrition therapy routes and between health care units will greatly contribute to recovery. The main objective is to preserve lean mass in critically ill patients, considering metabolic factors, adequate protein intake and muscle stimulation. (3) Continuous monitoring is required for the successful implementation of any health strategy. We lack precise tools for calculating nutritional efficiency in critically ill patients, therefore thorough monitoring of the process is essential. (4) The medical nutrition approach in critically ill patients is multidisciplinary and requires the participation of the entire team involved. A comprehensive strategy such as this can make a significant difference in the functional recovery of critically ill patients, but leaders must be identified to promote training, evaluation, analysis and feedback as essential components of its implementation, and to coordinate this process with the recognition of hospital management.

Challenges in identifying malnutrition in obesity; An overview of the state of the art and directions for future research

(Protein-energy) malnutrition in individuals living with obesity presents complex diagnostic challenges due to the distinctive physiological characteristics of obesity. This narrative review critically examines the identification of malnutrition within the population with obesity, distinguishing malnutrition in obesity from related conditions such as sarcopenic obesity. While noting some shared features, the review highlights key differences between these conditions. The review also highlights the limitations of current malnutrition screening tools, which are not designed for individuals living with obesity. These tools primarily rely on anthropometric measurements, neglecting (among others) nutrient intake assessment, which hinders accurate malnutrition detection. Additionally, this review discusses limitations in existing diagnostic criteria, including the Global Leadership Initiative on Malnutrition (GLIM) criteria, when applied to individuals living with obesity. Challenges include the identification of appropriate cut-off values for phenotypic criteria (unintentional weight loss, low body mass index and muscle mass) and aetiological criteria such as reduced food intake and inflammation for the population with obesity. Overall, this review emphasises the need for modified screening tools and diagnostic criteria to recognise and assess malnutrition in obesity, leading to improved clinical outcomes and overall wellbeing.

Nutritional management during critical illness in those with previous obesity surgery

PURPOSE OF REVIEW

The prevalence of overweight and obesity in our society is a pressing concern that has demanded immediate attention. Traditional treatments have proven ineffective for many individuals, leading to a surge in bariatric surgery as a last resort. While the rate of early and late postoperative complications may be low, when they occur, they place these patients at higher risk of requiring intensive care treatment. Therefore, it is our aim to discuss the nutritional care of these individuals.

RECENT FINDINGS

Nutritional management of critically ill postbariatric surgical patients is related to the difficulty of providing an adequate nutritional assessment, calculating the macro and micronutrient requirements, choosing the right therapy, and defining the timely moment to initiate it. The anatomic changes related to the bariatric operation pose a high risk for a nonfunctional gastrointestinal tract both in the early postoperative and late postoperative. Therefore, the route of nutrition will greatly rely on the absorptive capacity, as well as on the nutritional status, with parenteral nutrition being an early option, especially for those with high critical care severity scores. Also, these patients are known to have an altered microbiota which may influence the absorptive capacity. Immunonutrition, prebiotics, probiotics, and symbiotics may represent potential options, but there is currently little support for 'one size fits all'.

SUMMARY

The nutritional care of critically ill patients postbariatric surgery is a complex and nuanced process requiring a multifaceted precision approach. The distinct nutritional challenges of early and late postoperative patients necessitate a thorough nutritional assessment and a highly individualized nutritional care plan.

Physical and respiratory therapy in the critically ill patient with obesity: a narrative review

Obesity has become increasingly prevalent in the intensive care unit, presenting a significant challenge for healthcare systems and professionals, including rehabilitation teams. Caring for critically ill patients with obesity involves addressing complex issues. Despite the well-established and safe practice of early mobilization during critical illness, in rehabilitation matters, the diverse clinical disturbances and scenarios within the obese patient population necessitate a comprehensive understanding. This includes recognizing the importance of metabolic support, both non-invasive and invasive ventilatory support, and their weaning processes as essential prerequisites. Physiotherapists, working collaboratively with a multidisciplinary team, play a crucial role in ensuring proper assessment and functional rehabilitation in the critical care setting. This review aims to provide critical insights into the key management and rehabilitation principles for obese patients in the intensive care unit.

Characteristics and feeding intolerance in critically ill adult patients receiving peptide-based enteral nutrition: A retrospective cross-sectional study

BACKGROUND & AIMS

Patients who experience gastrointestinal (GI) intolerance and hyperglycemia (or glucose intolerance) may not achieve appropriate caloric requirements and experience poor outcomes. The aim was to examine patient characteristics, disease severity, and enteral nutrition (EN) formula use in relation to feeding intolerance and healthcare resource utilization.

METHODS

A retrospective, cross-sectional design using real-world data from PINC AI™ Healthcare Database, 2015-2019 was used. Critically ill hospitalized adults who required ≥3 days of 100% whey peptide-based EN, other peptide-based diets, or intact-protein standard and diabetic EN formulas were included. Primary outcomes were enteral feeding intolerance, including GI intolerance and hyperglycemia. Pairwise comparisons of other peptide-based and standard intact-protein groups with 100% whey-peptide were completed. Associations between EN group with GI intolerance and hyperglycemia, respectively, were evaluated via multivariable logistic regressions.

RESULTS

Across 67 US hospitals, 19,679 inpatients (3242,100% whey-peptide, 3121 other peptide-based, and 13,316 standard intact-protein) were included. The 100% whey-peptide group had higher severity of illness and frequencies of comorbidities compared with other peptide-based and standard intact-protein groups. Hospital length of stay, intensive care unit stay, and 30-day readmission were similar across peptide-based cohorts. After controlling for demographic, visit, and severity characteristics, odds of GI intolerance were 18% higher for the other peptide-based group and 15% higher for the standard intact-protein group compared with the 100% whey-peptide group (each P < 0.03). In secondary analysis, odds of hyperglycemia were 81% higher for the other peptide-based group compared with the subgroup of very high-protein/low carbohydrate 100% whey-peptide (P < 0.001).

CONCLUSIONS

Lower GI intolerance and greater glycemic control were associated with the use of 100% whey-peptide formulas relative to other formulas. Appropriate and optimal delivery of EN using specialized peptide-based formulas is a strategy to minimize feeding intolerance and benefit critically ill patients.

Effectiveness of school-based nutrition interventions promoted in the League of Arab States: a systematic review

Arab countries are doubly burdened with undernutrition as well as overweight and obesity. To provide guidance to those looking to address concerns of obesity and overweight among children in this region, the current review bridges an existing knowledge gap and systematically characterizes and evaluates the available scientific evidence pertaining to school-based nutrition interventions completed to date across the Arab world. Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and relevant keywords, terms and phrases, a search of the literature across 14 databases for school-based nutrition interventions implemented in this region was conducted. Out of 1568 articles from 14 databases, 38 full-text articles meeting the inclusion criteria were retrieved. Further assessment for eligibility excluded 23 articles and included one article from hand-searching references, leaving 16 articles in the final analysis. Most articles (n = 7) with the implementation of 5 months or longer found strong positive and significant impacts on limiting sweets consumption, increased dietary knowledge, self-efficacy, breakfast and fruit and vegetable consumption, among others. We also found evidence (n = 5) that teachers trained by experts such as dietitians and pediatricians can effectively implement nutrition interventions that achieve the intended outcomes. Training teachers to implement theory-based nutrition and health promotion curricula serves as a potential solution to improving nutrition knowledge, health behaviors and dietary practices among children living in Arab countries. Appropriately designed and implemented nutrition interventions can positively impact nutrition knowledge, health and diet-related behaviors in children and adolescents in this region.

Exploring Overnutrition, Overweight, and Obesity in the Hospital Setting-A Point Prevalence Study

Malnutrition is an international healthcare concern associated with poor patient outcomes, increased length of stay, and healthcare costs. Although malnutrition includes both under and overnutrition, there is a large body of evidence that describes the impacts of undernutrition with limited data on overnutrition in hospitalized patients. Obesity itself is a modifiable risk factor associated with hospital-associated complications. However, there is limited reporting of the prevalence of obesity in hospitals. This one-day cross-sectional study (n = 513) captures the prevalence of both under and overnutrition in a hospitalized population and explores dietetic care provided compared to the Nutrition Care Process Model for hospitalized patients who have obesity. The main findings were: (1) the largest proportion of patients were in the overweight and obese classifications (57.3%, n = 294/513); 5.3% of these patients had severe obesity (class III); (2) patients who were overweight and obese had lower malnutrition risk profiles as well as the prevalence of malnutrition; (3) 24.1% of patients who had obesity (n = 34/141) were receiving dietetic intervention; (4) 70.6% (n = 24/34) did not have a nutrition diagnosis that followed the Nutrition Care Process Model. Study results provide valuable clinical insight into the prevalence of overnutrition and opportunities to improve nutrition care for this vulnerable patient group.

How do guideline recommended energy targets compare with measured energy expenditure in critically ill adults with obesity: A systematic literature review

BACKGROUND

Critically ill patients with obesity have unique and complex nutritional needs, with clinical practice guidelines conflicting regarding recommended energy targets. The aim of this systematic review was to 1) describe measured resting energy expenditure (mREE) reported in the literature and; 2) compare mREE to predicted energy targets using the European (ESPEN) and American (ASPEN) guideline recommendations when indirect calorimetry is not available in critically ill patients with obesity.

METHODS

The protocol was registered apriori and literature was searched until 17th March, 2022. Original studies were included if they reported mREE using indirect calorimetry in critically ill patients with obesity (BMI≥30 kg/m²). Group-level mREE data was reported as per the primary publication using mean ± standard deviation or median [interquartile range]. Where individual patient data was available, Bland-Altman analysis was used to assess mean bias (95% limits of agreement) between guideline recommendations and mREE targets (i.e. ASPEN for BMI 30-50, 11-14 kcal/kg actual weight compared to 70% mREE and ESPEN 20-25 kcal/kg adjusted weight compared to 100% mREE). Accuracy was assessed by the percentage (%) of estimates within ±10% of mREE targets.

RESULTS

After searching 8019 articles, 24 studies were included. mREE ranged from 1607 ± 385 to 2919 [2318-3362]kcal and 12-32kcal/actual body weight. For the ASPEN recommendations of 11-14 kcal/kg, a mean bias of -18% (-50% to +13%) and 4% (-36% to +44%) was observed, respectively (n = 104). For the ESPEN recommendations 20-25 kcal/kg, a bias of -22% (-51% to +7%) and -4% (-43% to +34%), was observed, respectively (n = 114). The guideline recommendations were able to accurately predict mREE targets on 30%-39% occasions (11-14 kcal/kg actual) and 15%-45% occasions (20-25 kcal/kg adjusted), for ASPEN and ESPEN recommendations, respectively.

CONCLUSIONS

Measured energy expenditure in critically ill patients with obesity is variable. Energy targets generated using predictive equations recommended in both the ASPEN and ESPEN clinical guidelines have poor agreement with mREE and are frequently not able to accurately predict within ±10% of mREE, most commonly underestimating energy needs.

Leaf Extract of Perilla frutescens (L.) Britt Promotes Adipocyte Browning via the p38 MAPK Pathway and PI3K-AKT Pathway

The leaf of Perilla frutescens (L.) Britt (PF) has been reported to negatively affect adipocyte formation, inhibit body-fat formation, and lower body weight. However, its effect on adipocyte browning remains unknown. Thus, the mechanism of PF in promoting adipocyte browning was investigated. The ingredients of PF were acquired from the online database and filtered with oral bioavailability and drug-likeness criteria. The browning-related target genes were obtained from the Gene Card database. A Venn diagram was employed to obtain the overlapped genes that may play a part in PF promoting adipocyte browning, and an enrichment was analysis conducted based on these overlapped genes. A total of 17 active ingredients of PF were filtered, which may regulate intracellular receptor-signaling pathways, the activation of protein kinase activity, and other pathways through 56 targets. In vitro validation showed that PF promotes mitochondrial biogenesis and upregulates brite adipocyte-related gene expression. The browning effect of PF can be mediated by the p38 MAPK pathway as well as PI3K-AKT pathway. The study revealed that PF could promote adipocyte browning through multitargets and multipathways. An in vitro study validated that the browning effect of PF can be mediated by both the P38 MAPK pathway and the PI3K-AKT pathway.