Biomarkers in critical care nutrition

Glucagon-Like Peptide-1 Is Prognostic of Mortality in Acute Respiratory Failure

OBJECTIVES

The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) have therapeutic effects in diabetes mellitus. Prior clinical studies suggest incretins are prognostic of adverse outcomes in critical illness. We investigated whether incretin levels indicate disease severity and clinical outcomes in patients with acute respiratory failure, a common cause of critical illness.

DESIGN

Retrospective cohort study.

SETTING

ICUs in UPMC Health Systems hospitals within Western Pennsylvania.

PATIENTS

Two hundred ninety-seven critically ill adults with acute respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured GLP-1 and GIP levels in baseline samples collected at the time of study enrollment. We compared incretin levels across subgroups differing by severity of illness and investigated associations between incretins and markers of systemic host responses and intestinal permeability. In our primary analysis, we tested the association of each incretin level with 90-day mortality by logistic regression in unadjusted analyses and in analyses adjusted for age, Sequential Organ Failure Assessment score, and circulating interleukin-6 levels. GLP-1 levels were higher in nonsurvivors and patients with or at-risk for acute respiratory distress syndrome compared to those intubated for airway protection. GLP-1 levels also positively correlated with systemic immune response biomarkers but not with markers of intestinal permeability. GLP-1 levels positively correlated with mortality in unadjusted (odds ratio, 1.99 [1.55-2.56]; p < 0.01) and adjusted (2.02 [1.23-3.31]; p < 0.01) analyses. GIP levels were not associated with mortality or with host response biomarkers.

CONCLUSIONS

GLP-1 but not GIP levels were positively associated with systemic inflammation and mortality in critically ill patients with acute respiratory failure. Increased circulating GLP-1 levels may serve as prognostic biomarkers to identify patients who are likely to have worse outcomes.

Why One-Size-Fits-All Doesn't Work in Intensive Care Unit Nutrition?

Nutrition therapy is a complex intervention with several underlying considerations that may influence effectiveness. Considerations include the mechanism of action of the intervention and the patient phenotype, including sex, ethnicity, body composition, and the patients' nutritional and inflammatory status. Energy and protein targets are elements of nutrition therapy that may be particularly influenced by individual patient factors. Biomarkers may provide a useful tool to monitor and individualize nutrition therapy in the future. The considerations mentioned, with many yet to be studied, highlight the rationale for more individualized interventions moving away from a 'one-size-fits-all' approach.

Toward Precision in Nutrition Therapy

Precision in critical care nutrition is paramount, as it focuses nutrition interventions on those patients most likely to benefit, or those who might potentially be harmed. Critical care nutrition must therefore be tailored to individual metabolic needs as determined by factors that control the capacity for tissue homeostasis and anabolic responses. This ideally involves the accurate and timely assessment of macronutrient and micronutrient requirements, a careful evaluation of metabolic response mechanisms and the identification of circumstances that might interfere with the productive utilization of dietary substrates. Specific surrogate markers of metabolic response, such as blood glucose levels, urea levels, or nitrogen balance, might be used to evaluate the metabolic readiness for nutrition and to establish the timing, nature, and clinical effectiveness of nutrition interventions. Despite the pressing need to further develop more targeted approaches in critically ill patients, indices of immediate metabolic responses that correlate with favorable clinical outcomes are lacking. In addition, the development of precision approaches might address timely adjustments in protein, energy, or micronutrient supplementation based on evolving clinical conditions. Here, we review why precision tools are needed in critical care nutrition, our progress thus far, as well as promising approaches and technologies by which multidisciplinary healthcare teams can improve quality of care and clinical outcomes by individualizing nutrition interventions.

Nine Myths about Enteral Feeding in Critically Ill Adults: An Expert Perspective

Malnutrition is a well-studied and significant prognostic risk factor for morbidity and mortality in critically ill perioperative patients. Common nutrition myths in the critically ill may prevent early, consistent, and adequate delivery of enteral nutrition. We outlined 9 common intensive care unit (ICU) nutrition misconceptions and our recommendations to optimize enteral nutrition in critically ill patients based on the review of available literature. Our approach is to treat every patient admitted to the ICU as at risk for malnutrition and to initiate enteral nutrition upon admission in the absence of contraindications. Early enteral nutrition via the gastric route is more beneficial than delaying feeding while awaiting small bowel access and daytime-intermittent nutrition support can safely be initiated over continuous feeding. Gastric residual volumes to assess feeding tolerance should no longer be routinely measured. For perioperative nutrition, we recommend continuing enteral nutrition for most patients with secure airways undergoing anesthesia and resuming nutrition within 24 h of abdominal surgery; even patients with open abdomens can be safely fed in the absence of bowel injury. Critically ill patients who are proned, paralyzed, and on vasopressors can usually continue enteral nutrition. Finally, continuing enteral nutrition before extubation may optimize nutrition without compromising extubation success. In this review, we highlight several common misconceptions regarding ICU nutrition that may prevent achieving nutrition goals and subsequently lead to increased malnutrition, morbidity, and mortality. This knowledge may contribute to increased implementation of early and consistent enteral nutrition strategies to improve outcomes in critically ill adult patients.

Total cholesterol and bilirubin levels are associated with neurologic outcomes in patients with out-of-hospital cardiac arrest

BACKGROUND

Assessing the neurologic outcomes of patients who experience out of hospital cardiac arrest (OHCA) is challenging. Neurologic outcomes were evaluated using initial nutrition related biochemical markers.

METHODS

We used data from a multicentre retrospective observational study, the Korean Cardiac Arrest Resuscitation Consortium (KoCARC) registry. Among the 666 patients, 217 had good neurologic outcomes, while 449 had poor neurologic outcomes. Multivariate logistic regression and classification and regression tree (CART) analyses were employed.

RESULT

In the multivariate logistic regression analysis, total cholesterol ≥ 158.5 mg/dL, total bilirubin ≥ 0.265 mg/dL, Sodium < 142.1 mEq/L, AST < 200.5 U/L and were identified as significant biomarkers for good neurologic outcomes. In the CART analysis, total cholesterol ≥ 158.5 mg/dL and total bilirubin ≥ 0.365 mg/dL were found to be significant indicators. In additional analysis, when the total bilirubin level ranged from 0.6 to 0.7 mg/dL, the highest rate of a good neurologic outcome was observed at 44.6%, whereas levels below or above this range gradually indicated a lower rate of a good neurologic outcome.

CONCLUSION

We propose that total cholesterol and total bilirubin levels could serve as valuable indicators for predicting neurologic outcomes in patients with OHCA.

Urea to creatinine ratio as a predictor of persistent critical illness

INTRODUCTION

Persistent critical illness (PCI) is a syndrome in which the acute presenting problem has been stabilized, but the patient's clinical state does not allow ICU discharge. The burden associated with PCI is substantial. The most obvious marker of PCI is prolonged ICU length of stay (LOS), usually greater than 10 days. Urea to Creatinine ratio (UCr) has been suggested as an early marker of PCI development.

METHODS

A single-center retrospective study. Data of patients admitted to a general mixed medical-surgical ICU during Jan 1st 2018 till Dec 31st 2022 was extracted, including demographic data, baseline characteristics, daily urea and creatinine results, renal replacement therapy (RRT) provided, and outcome measures - length of stay, and mortality (ICU, and 90 days). Patients were defined as PCI patients if their LOS was >10 days. We used Fisher exact test or Chi-square to compare PCI and non-PCI patients. The association between UCr with PCI development was assessed by repeated measures linear model. Multivariate Cox regression was used for 1 year mortality assessment.

RESULTS

2098 patients were included in the analysis. Patients who suffered from PCI were older, with higher admission prognostic scores. Their 90-day mortality was significantly higher than non-PCI patients (34.58% vs 12.18%, p < 0.0001). A significant difference in UCr was found only on the first admission day among all patients. This was not found when examining separately surgical, trauma, or transplantation patients. We did not find a difference in UCr in different KDIGO (Kidney Disease Improving Global Outcomes) stages. Elevated UCr and PCI were found to be significantly associated with 1 year mortality.

CONCLUSION

In this single center retrospective cohort study, UCr was not found to be associated with PCI development.

Fasting in critical illness: the role of ketonuria - a retrospective observational study

BACKGROUND

Metabolic acidosis is a frequent finding in patients admitted to the intensive care unit (ICU). It can be caused by prolonged fasting due to surgical procedures or by medical conditions that lead to starvation ketoacidosis (SKA). Early recognition and treatment of SKA could prevent several life-threatening complications, improving survival and reducing the ICU length of stay.

METHODS

We retrospectively screened all medical records of patients admitted to the ICU (Maggiore Hospital, Bologna, North Italy) from May 2022 to April 2023. We included patients aged 18 years or older who presented ketonuria detected in the urine sample.

RESULTS

We analyzed 190 patients with ketonuria at ICU admission. Postsurgical patients showed lower levels of albumin and a higher rate of shock compared to medical patients. Ketonuric patients with shock had a lower body mass index (BMI) compared to patients without shock (24 versus 26 kg/m2, respectively). There were no differences within groups regarding mortality and ICU readmission rate. Medical patients had a significantly higher ICU length of stay.

CONCLUSIONS

This retrospective observational descriptive study showed that patients with ketonuria, hypoalbuminemia, and low BMI at ICU admission have high risk of hemodynamic instability and shock. Surgical patients compared to medical patients are exposed to a catabolic trigger that could worsen a state of malnutrition and induce anabolic resistance; elective and urgent surgical patients did not differ in terms of risk of shock and mortality, probably due to the activation of this catabolic pathway. Early recognition and treatment of starvation ketoacidosis and perioperative nutritional optimization could reduce incidence of hemodynamic and metabolic complications.

Relationship between very early enteral nutrition and persistent inflammation, immunosuppression, and catabolism syndrome in cardiovascular surgery patients: a propensity score-matched study

BACKGROUND

Early enteral nutrition (EN) is recommended for patients with critical illness to maintain intestinal immunity. However, the optimal timing of the commencement of EN remains unclear, particularly after cardiovascular surgery.

OBJECTIVES

We herein focused on Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) as a predisposing immunodeficiency and investigated its association with very early EN (VEEN) (<24 h) in patients who underwent cardiovascular surgery.

METHODS

In this retrospective study, we used an administrative claims database with laboratory examinations between 2008 and 2021 to identify adult patients admitted to the intensive care unit after cardiovascular surgery. Patients who received EN the day after surgery were assigned to the EN <24 h group, whereas those who received EN on day 2 or day 3 were assigned to the control group. The primary outcome was a composite of the incidence of PICS and mortality on day 14 after surgery. We defined PICS as patients who were hospitalized for >14 day and meeting ≥2 of the following conditions: a lymphocyte count <800/μL, albumin <3.0 g/dL, and C-reactive protein >2.0 mg/dL. We compared the 2 groups using propensity score analysis.

RESULTS

A propensity score matching generated 2082 pairs. The primary outcome was significantly lower in the EN <24 h group than in the control group on days 14 {risk difference [95% confidence interval (CI)]: -3.1% [-5.9%, -0.3%]} and 28 (risk difference [95% CI]: -2.1% [-3.7%, -0.4%]). Mortality did not significantly differ between the 2 groups. The length of hospital stay was significantly shorter in the EN <24 h group: the difference (95% CI) was -2.2 (-3.7, -0.7) d.

CONCLUSIONS

Among patients who underwent cardiovascular surgery, VEEN provided on the day after surgery was associated with a lower incidence of PICS and a shorter length of hospital stay than EN provided 2 day or 3 day after surgery.

The role of lipid emulsions containing omega-3 fatty acids for medical and surgical critical care patients

In critical illness the regulation of inflammation and oxidative stress can improve patient outcomes, and thus omega-3 polyunsaturated fatty acids (PUFAs) have been used as part of parenteral nutrition (PN) owing to their potential anti-inflammatory effects. The international lipids in PN Summit, encompassed discussions and the production of consensus guidelines concerning PN intravenous lipid emulsion (ILE) use in critical care. The Lipid Summit participants agreed that the inclusion of fish oil in ILEs is associated with meaningful clinical benefits without signals of harm, based on a strong biological rationale and current clinical evidence. Decisions concerning ILE choice should be made based on current evidence, thus addressing clinical requirements for guidance, particularly as further definitive evidence seems unlikely to occur. In addition, a future of individualized ICU care is envisioned, yielding better clinical outcomes. This approach will require the greater use of intelligent study designs incorporating the use of biomarkers of omega-3 derivatives, inflammatory-resolving processes, and/or muscle protein breakdown.

Dynamic assessment of prealbumin for nutrition support effectiveness in critically ill patients

BACKGROUND & AIMS

Serum prealbumin is considered to be a sensitive predictor of clinical outcomes and a quality marker for nutrition support. However, its susceptibility to inflammation restricts its usage in critically ill patients according to current guidelines. We assessed the performance of the initial value of prealbumin and dynamic changes for predicting the ICU mortality and the effectiveness of nutrition support in critically ill patients.

METHODS

This monocentric study included patients admitted to the ICU between 2009 and 2016, having at least one initial prealbumin value available. Prospectively recorded data were extracted from the electronic ICU charts. We used both univariable and multivariable logistic regressions to estimate the performance of prealbumin for the prediction of ICU mortality. Additionally, the association between prealbumin dynamic changes and nutrition support was assessed via a multivariable linear mixed-effects model and multivariable linear regression. Performing subgroup analysis assisted in identifying patients for whom prealbumin dynamic assessment holds specific relevance.

RESULTS

We included 3136 patients with a total of 4942 prealbumin levels available. Both prealbumin measured at ICU admission (adjusted odds-ratio (aOR) 0.04, confidence interval (CI) 95% 0.01-0.23) and its change over the first week (aOR 0.02, CI 95 0.00-0.19) were negatively associated with ICU mortality. Throughout the entire ICU stay, prealbumin dynamic changes were associated with both cumulative energy (estimate: 33.2, standard error (SE) 0.001, p < 0.01) and protein intakes (1.39, SE 0.001, p < 0.01). During the first week of stay, prealbumin change was independently associated with mean energy (6.03e-04, SE 2.32e-04, p < 0.01) and protein intakes (1.97e-02, SE 5.91e-03, p < 0.01). Notably, the association between prealbumin and energy intake was strongest among older or malnourished patients, those suffering from increased inflammation and those with high disease severity. Finally, prealbumin changes were associated with a positive mean nitrogen balance at day 7 only in patients with SOFA <4 (p = 0.047).

CONCLUSION

Prealbumin measured at ICU admission and its change during the first-week serve as an accurate predictor of ICU mortality. Prealbumin dynamic assessment may be a reliable tool to estimate the effectiveness of nutrition support in the ICU, especially among high-risk patients.

The impact of guideline recommended protein intake on mortality and length of intensive care unit and hospital stay in critically ill adults: A systematic review

International guidelines recommend a target protein intake of ≥1.2 g/kg/day to all critically ill patients for optimal outcomes. There are however various conflicting data related to this recommendation. The primary objective of this review was to compare a protein intake group (≥1.2 g/kg/day) with a lower protein intake group (<1.2 g/kg/day) in critically ill adult patients on mortality, length of intensive care unit (ICU) and hospital stay. Secondly, the effect of protein intake on length of mechanical ventilation, adverse nutrition-related events and muscle mass and strength parameters were investigated. Sixteen randomised controlled trials (RCTs) of adult patients admitted to an intensive or high care unit and receiving nutrition support in the form of enteral- and/or parenteral nutrition were selected against prespecified eligibility criteria. Two independent reviewers extracted relevant data and assessed the risk of bias of the included studies. Review Manager 5.4.1 was used to analyse data and GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) was used to evaluate the certainty of the evidence. The higher protein group, when compared to the lower protein group, probably results in little to no difference in mortality (risk ratio [RR] 1.01; 95% confidence interval [CI]: 0.89 to 1.14; moderate-certainty evidence); with a probable slight increase in length of ICU stay (mean difference [MD] 0.33; 95% CI -0.57 to 1.23; moderate-certainty) and length of hospital stay (MD 1.72; 95% CI -0.58 to 4.01; moderate-certainty evidence), on average. For secondary outcomes, it was found that the higher protein group probably does not reduce the length of mechanical ventilation (MD 0.08; 95% CI -0.38 to 0.53; moderate-certainty evidence). Higher protein group probably reduces the occurrence of diarrhoea and high gastric residual volume and may reduce the occurrence of constipation. It may also increase nitrogen balance (MD 3.66; 95% CI 1.81 to 5.51; low-certainty evidence). Importantly, there does not seem to be harm associated with the higher protein group, though it should be mentioned that for many of the adverse events in this study, the certainty of evidence was low or very low.

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.

Micronutrients as therapy in critical illness

PURPOSE OF REVIEW

Recent large-scale randomized controlled trials (RCTs) challenged current beliefs about the potential role of micronutrients to attenuate the inflammatory response and improve clinical outcomes of critically ill patients. The purpose of this narrative review is to provide an overview and critical discussion about most recent clinical trials, which evaluated the clinical significance of a vitamin C, vitamin D, or selenium administration in critically ill patients.

RECENT FINDINGS

None of the most recent large-scale RCTs could demonstrate any clinical benefits for a micronutrient administration in ICU patients, whereas a recent RCT indicated harmful effects, if high dose vitamin C was administered in septic patients. Following meta-analyses could not confirm harmful effects for high dose vitamin C in general critically ill patients and indicated benefits in the subgroup of general ICU patients with higher mortality risk. For vitamin D, the most recent large-scale RCT could not demonstrate clinical benefits for critically ill patients, whereas another large-scale RCT is still ongoing. The aggregated and meta-analyzed evidence highlighted a potential role for intravenous vitamin D administration, which encourages further research. In high-risk cardiac surgery patients, a perioperative application of high-dose selenium was unable to improve patients' outcome. The observed increase of selenium levels in the patients' blood did not translate into an increase of antioxidative or anti-inflammatory enzymes, which illuminates the urgent need for more research to identify potential confounding factors.

SUMMARY

Current data received from most recent large-scale RCTs could not demonstrate clinically meaningful effects of an intervention with either vitamin C, vitamin D, or selenium in critically ill patients. More attention is needed to carefully identify potential confounding factors and to better evaluate the role of timing, duration, and combined strategies.

Clinical practice guidelines for nutritional assessment and monitoring of adult ICU patients in China

The Chinese Society of Critical Care Medicine (CSCCM) has developed clinical practice guidelines for nutrition assessment and monitoring for patients in adult intensive care units (ICUs) in China. This guideline focuses on nutrition evaluation and metabolic monitoring to achieve optimal and personalized nutrition therapy for critically ill patients. This guideline was developed by experts in critical care medicine and evidence-based medicine methodology and was developed after a thorough review of the system and a summary of relevant trials or studies published from 2000 to July 2023. A total of 18 recommendations were formed and consensus was reached through discussions and reviews by expert groups in critical care medicine, parenteral and enteral nutrition, and surgery. The recommendations are based on currently available evidence and cover several key fields, including screening and assessment, evaluation and assessment of enteral feeding intolerance, metabolic and nutritional measurement and monitoring during nutrition therapy, and organ function evaluation related to nutrition supply. Each question was analyzed according to the Population, Intervention, Comparison, and Outcome (PICO) principle. In addition, interpretations were provided for four questions that did not reach a consensus but may have potential clinical and research value. The plan is to update this nutrition assessment and monitoring guideline using the international guideline update method within 3-5 years.

Nutritional support and prevention of post-intensive care syndrome: the Italian SIAARTI survey

BACKGROUND

Malnutrition and muscle wasting are common in ICU patients and predict adverse patient-centered outcomes. The Italian Society of Anesthesia Analgesia Resuscitation and Intensive Care (SIAARTI) conducted a nationwide survey to identify the nutritional practices in the Italian ICUs and to plan future, training interventions to improve the national clinical practice.

METHODS

Nationwide online survey, involving Italian ICUs, developed by experts affiliated with SIAARTI. Invitations to participate were distributed through emails and social networks. Data were collected over a period of three months (October 1 to December 31, 2022) during 2022.

RESULTS

One hundred full responses from participating ICUs were collected. The number of beds is < 10 in most ICUs and > 20 in 11 ICUs. Most ICUs (87%) are mixed, cardiac (5%), neurosurgical (4%), or pediatric ICUs (1%). Although the nutritional program is widely prescribed based on the patients' general evaluation, 52 ICUs (52%) do not perform nutritional risk evaluation at admission in case of > 24-h stay. Daily caloric intake is mainly based on the 25 kcal/kg equation; otherwise, the Harris-Benedict formula is mostly used, whereas indirect calorimetry is less used. Most clinicians apply a personalized nutritional approach to organ failure. Most ICUs have a nutritional management protocol, and enteral nutrition (EN) is frequently started within 2 days from admission, while supplemental parenteral nutrition is used when EN is insufficient by most clinicians. The EN administered seems to correspond to that prescribed, but it is stopped if the gastric residual gastric is > 300-500 ml in most ICUs.

CONCLUSION

Prescription, route, and mode of administration of nutritional support seem to be in line with international recommendations, while suggestions on the tools for assessing the nutritional risk and monitoring efficacy and complications seem far less followed. Future national clinical studies are necessary to investigate the optimal nutritional and metabolic management of critically ill patients and the correspondence with the results of this survey on actual practices.

The impact of higher protein dosing on outcomes in critically ill patients with acute kidney injury: a post hoc analysis of the EFFORT protein trial

BACKGROUND

Based on low-quality evidence, current nutrition guidelines recommend the delivery of high-dose protein in critically ill patients. The EFFORT Protein trial showed that higher protein dose is not associated with improved outcomes, whereas the effects in critically ill patients who developed acute kidney injury (AKI) need further evaluation. The overall aim is to evaluate the effects of high-dose protein in critically ill patients who developed different stages of AKI.

METHODS

In this post hoc analysis of the EFFORT Protein trial, we investigated the effect of high versus usual protein dose (≥ 2.2 vs. ≤ 1.2 g/kg body weight/day) on time-to-discharge alive from the hospital (TTDA) and 60-day mortality and in different subgroups in critically ill patients with AKI as defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria within 7 days of ICU admission. The associations of protein dose with incidence and duration of kidney replacement therapy (KRT) were also investigated.

RESULTS

Of the 1329 randomized patients, 312 developed AKI and were included in this analysis (163 in the high and 149 in the usual protein dose group). High protein was associated with a slower time-to-discharge alive from the hospital (TTDA) (hazard ratio 0.5, 95% CI 0.4-0.8) and higher 60-day mortality (relative risk 1.4 (95% CI 1.1-1.8). Effect modification was not statistically significant for any subgroup, and no subgroups suggested a beneficial effect of higher protein, although the harmful effect of higher protein target appeared to disappear in patients who received kidney replacement therapy (KRT). Protein dose was not significantly associated with the incidence of AKI and KRT or duration of KRT.

CONCLUSIONS

In critically ill patients with AKI, high protein may be associated with worse outcomes in all AKI stages. Recommendation of higher protein dosing in AKI patients should be carefully re-evaluated to avoid potential harmful effects especially in patients who were not treated with KRT.

TRIAL REGISTRATION

This study is registered at ClinicalTrials.gov (NCT03160547) on May 17th 2017.

Explorative Clustering of the Nitrogen Balance Trajectory in Critically Ill Patients: A Preliminary post hoc Analysis of a Single-Center Prospective Observational Study

BACKGROUND

The nitrogen balance estimates a protein net difference. However, since it has a number of limitations, it is important to consider the trajectory of the nitrogen balance in the clinical course of critically ill patients.

OBJECTIVES

We herein exploratively classified the nitrogen balance trajectory using a machine learning method.

METHOD

This is a post hoc analysis of a single-center prospective study for the patients admitted to our Emergency and Critical Center ICU. The nitrogen balance was evaluated with 24-h urine collection from ICU days 1-10 with 9 points. K-means clustering was performed to classify the nitrogen balance trajectory. We also evaluated factors associated with uncovered clusters.

RESULTS

Seventy-six eligible patients were included in the present study. After clustering, the nitrogen balance trajectory was classified into 4 classes. Class 1 was trajected as a negative balance over 10 days (24 patients). Class 2 had a positive conversion on day 3 or 4 (8 patients). Class 3 had a positive conversion on day 8 or 9 (28 patients). Class 4 initially had a positive balance and then converted to a negative balance (16 patients). Sepsis complication and steroid use were associated with negative nitrogen balance trajectory. Class 2 was associated with lower length of hospital stay and femoral muscle volume loss, however, frequently had frailty and sarcopenia on admission. Active nutrition therapy intention was not correlated with positive trajectory.

CONCLUSIONS

The nitrogen balance trajectory in critically ill patients may be classified into 4 classes for clinical practice. Among patients emergently admitted to the ICU, the positive conversion of the nitrogen balance might be delayed over 10 days.

Body composition in pediatric patients

Undernutrition is highly prevalent in children who are critically ill and is associated with increased morbidity and mortality, including a higher risk of infection due to transitory immunological disorders, inadequate wound healing, reduced gut function, longer dependency on mechanical ventilation, and longer hospital stays compared with eutrophic children who are critically ill. Nutrition care studies have proposed that early interventions targeting nutrition assessment can prevent or minimize the complications of undernutrition. Stress promotes an acute inflammatory response mediated by cytokines, resulting in increased basal metabolism and nitrogen excretion and leading to muscle loss and changes in body composition. Therefore, the inclusion of body composition assessment is important in the evaluation of these patients because, in addition to the nutrition aspect, body composition seems to predict clinical prognosis. Several techniques can be used to assess body composition, such as arm measurements, calf circumference, grip strength, bioelectrical impedance analysis, and imaging examinations, including computed tomography and dual-energy x-ray absorptiometry. This review of available evidence suggests that arm measurements seem to be well-established in assessing body composition in children who are critically ill, and that bioelectrical impedance analysis with phase angle, handgrip strength, calf circumference and ultrasound seem to be promising in this evaluation. However, further robust studies based on scientific evidence are necessary.

The impact of age-related syndromes on ICU process and outcomes in very old patients

In this narrative review, we describe the most important age-related "syndromes" found in the old ICU patients. The syndromes are frailty, comorbidity, cognitive decline, malnutrition, sarcopenia, loss of functional autonomy, immunosenescence and inflam-ageing. The underlying geriatric condition, together with the admission diagnosis and the acute severity contribute to the short-term, but also to the long-term prognosis. Besides mortality, functional status and quality of life are major outcome variables. The geriatric assessment is a key tool for long-term qualitative outcome, while immediate severity accounts for acute mortality. A poor functional baseline reduces the chances of a successful outcome following ICU. This review emphasises the importance of using a geriatric assessment and considering the older patient as a whole, rather than the acute illness in isolation, when making decisions regarding intensive care treatment.

Effect of High-Dose Selenium on Postoperative Organ Dysfunction and Mortality in Cardiac Surgery Patients: The SUSTAIN CSX Randomized Clinical Trial

Importance

Selenium contributes to antioxidative, anti-inflammatory, and immunomodulatory pathways, which may improve outcomes in patients at high risk of organ dysfunctions after cardiac surgery.

Objective

To assess the ability of high-dose intravenous sodium selenite treatment to reduce postoperative organ dysfunction and mortality in cardiac surgery patients.

Design, Setting, and Participants

This multicenter, randomized, double-blind, placebo-controlled trial took place at 23 sites in Germany and Canada from January 2015 to January 2021. Adult cardiac surgery patients with a European System for Cardiac Operative Risk Evaluation II score-predicted mortality of 5% or more or planned combined surgical procedures were randomized.

Interventions

Patients were randomly assigned (1:1) by a web-based system to receive either perioperative intravenous high-dose selenium supplementation of 2000 μg/L of sodium selenite prior to cardiopulmonary bypass, 2000 μg/L immediately postoperatively, and 1000 μg/L each day in intensive care for a maximum of 10 days or placebo.

Main Outcomes and Measures

The primary end point was a composite of the numbers of days alive and free from organ dysfunction during the first 30 days following cardiac surgery.

Results

A total of 1416 adult cardiac surgery patients were analyzed (mean [SD] age, 68.2 [10.4] years; 1043 [74.8%] male). The median (IQR) predicted 30-day mortality by European System for Cardiac Operative Risk Evaluation II score was 8.7% (5.6%-14.9%), and most patients had combined coronary revascularization and valvular procedures. Selenium did not increase the number of persistent organ dysfunction-free and alive days over the first 30 postoperative days (median [IQR], 29 [28-30] vs 29 [28-30]; P = .45). The 30-day mortality rates were 4.2% in the selenium and 5.0% in the placebo group (odds ratio, 0.82; 95% CI, 0.50-1.36; P = .44). Safety outcomes did not differ between the groups.

Conclusions and Relevance

In high-risk cardiac surgery patients, perioperative administration of high-dose intravenous sodium selenite did not reduce morbidity or mortality. The present data do not support the routine perioperative use of selenium for patients undergoing cardiac surgery.

Trial Registration

ClinicalTrials.gov Identifier: NCT02002247.

Biomarkers as Prognostic Predictors and Therapeutic Guide in Critically Ill Patients: Clinical Evidence

A biomarker is a molecule that can be measured in a biological sample in an objective, systematic, and precise way, whose levels indicate whether a process is normal or pathological. Knowing the most important biomarkers and their characteristics is the key to precision medicine in intensive and perioperative care. Biomarkers can be used to diagnose, in assessment of disease severity, to stratify risk, to predict and guide clinical decisions, and to guide treatments and response to them. In this review, we will analyze what characteristics a biomarker should have and how to ensure its usefulness, and we will review the biomarkers that in our opinion can make their knowledge more useful to the reader in their clinical practice, with a future perspective. These biomarkers, in our opinion, are lactate, C-Reactive Protein, Troponins T and I, Brain Natriuretic Peptides, Procalcitonin, MR-ProAdrenomedullin and BioAdrenomedullin, Neutrophil/lymphocyte ratio and lymphopenia, Proenkephalin, NefroCheck, Neutrophil gelatinase-associated lipocalin (NGAL), Interleukin 6, Urokinase-type soluble plasminogen activator receptor (suPAR), Presepsin, Pancreatic Stone Protein (PSP), and Dipeptidyl peptidase 3 (DPP3). Finally, we propose an approach to the perioperative evaluation of high-risk patients and critically ill patients in the Intensive Care Unit (ICU) based on biomarkers.

Overview of oxidative stress and the role of micronutrients in critical illness

Inflammation and oxidative stress represent physiological response mechanisms to different types of stimuli and injury during critical illness. Its proper regulation is fundamental to cellular and organismal survival and are paramount to outcomes and recovery from critical illness. A proper maintenance of the delicate balance between inflammation, oxidative stress, and immune response is crucial for resolution from critical illness with important implications for patient outcome. The extent of inflammation and oxidative stress under normal conditions is limited by the antioxidant defense system of the human body, whereas the antioxidant capacity is commonly significantly compromised, and serum levels of micronutrients and vitamins significantly depleted in patients who are critically ill. Hence, the provision of antioxidants and anti-inflammatory nutrients may help to reduce the extent of oxidative stress and therefore improve clinical outcomes in patients who are critically ill. As existing evidence of the beneficial effects of antioxidant supplementation in patients who are critically ill is still unclear, actual findings about the most promising anti-inflammatory and antioxidative candidates selenium, vitamin C, zinc, and vitamin D will be discussed in this narrative review. The existing evidence provided so far demonstrates that several factors need to be considered to determine the efficacy of an antioxidant supplementation strategy in patients who are critically ill and indicates the need for adequately designed multicenter prospective randomized control trials to evaluate the clinical significance of different types and doses of micronutrients and vitamins in selected groups of patients with different types of critical illness.

Association between early nutrition support and 28-day mortality in critically ill patients: the FRANS prospective nutrition cohort study

BACKGROUND

Current guidelines suggest the introduction of early nutrition support within the first 48 h of admission to the intensive care unit (ICU) for patients who cannot eat. In that context, we aimed to describe nutrition practices in the ICU and study the association between the introduction of early nutrition support (< 48 h) in the ICU and patient mortality at day 28 (D28) using data from a multicentre prospective cohort.

METHODS

The 'French-Speaking ICU Nutritional Survey' (FRANS) study was conducted in 26 ICUs in France and Belgium over 3 months in 2015. Adult patients with a predicted ICU length of stay > 3 days were consecutively included and followed for 10 days. Their mortality was assessed at D28. We investigated the association between early nutrition (< 48 h) and mortality at D28 using univariate and multivariate propensity-score-weighted logistic regression analyses.

RESULTS

During the study period, 1206 patients were included. Early nutrition support was administered to 718 patients (59.5%), with 504 patients receiving enteral nutrition and 214 parenteral nutrition. Early nutrition was more frequently prescribed in the presence of multiple organ failure and less frequently in overweight and obese patients. Early nutrition was significantly associated with D28 mortality in the univariate analysis (crude odds ratio (OR) 1.69, 95% confidence interval (CI) 1.23-2.34) and propensity-weighted multivariate analysis (adjusted OR (aOR) 1.05, 95% CI 1.00-1.10). In subgroup analyses, this association was stronger in patients ≤ 65 years and with SOFA scores ≤ 8. Compared with no early nutrition, a significant association was found of D28 mortality with early enteral (aOR 1.06, 95% CI 1.01-1.11) but not early parenteral nutrition (aOR 1.04, 95% CI 0.98-1.11).

CONCLUSIONS

In this prospective cohort study, early nutrition support in the ICU was significantly associated with increased mortality at D28, particularly in younger patients with less severe disease. Compared to no early nutrition, only early enteral nutrition appeared to be associated with increased mortality. Such findings are in contrast with current guidelines on the provision of early nutrition support in the ICU and may challenge our current practices, particularly concerning patients at low nutrition risk. Trial registration ClinicalTrials.gov Identifier: NCT02599948. Retrospectively registered on November 5th 2015.

Vitamin requirements during stem cell transplantation: a systematic review

Patients undergoing stem cell transplantation (SCT) are at high risk of malnutrition during the acute post-transplantation period. This systematic review aimed to collate and analyse the evidence for vitamin requirements post-SCT. A systematic search of five databases was conducted to include studies published until March 2021. The review utilised the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) framework. Inclusion criteria consisted of adults undergoing SCT who received vitamin supplementation or had their vitamin levels monitored up to 100 days post-SCT. Studies with paediatric patients or those that looked at vitamin derivates such as folinic acid were excluded. Main outcomes included vitamin deficiency and relevant clinical outcomes. Eleven studies (n = 11) were eligible for inclusion with five rated as neutral quality and six as positive quality. Five studies focused on allogenic SCT, two on autologous SCT and the remaining included a mix of both. Eight studies monitored vitamins levels post-SCT, and seven studies provided vitamin supplementation. Three studies (one provided supplementation) found a high prevalence of vitamin D deficiency (23-60%) prior to SCT. Findings indicate an unclear association between vitamin deficiency and post-SCT complications including acute graft-versus-host-disease, oral mucositis, and mortality. The GRADE certainty of evidence across these outcomes was low or very low. It is unclear if supplementation is needed during SCT, though assessing vitamin D levels prior to transplant should be considered. Further large observational studies or randomised control trials are required to establish vitamin requirements and guide supplementation protocols during SCT.

Decrease phase angle one year after Roux-en-Y bypass and sleeve gastrectomy is related to risks to protein nutritional status

BACKGROUND & AIMS

Phase angle (PhA) has been used as an indicator of nutritional status. However, the significance of PhA reduction after bariatric surgery is less known. This study evaluated PhA and its relation with biochemical parameters and prognostic inflammatory and nutritional indices at a one-year follow-up of patients subjected to Roux-en-Y bypass (RYGB) or sleeve gastrectomy (SG).

METHODS

Our final sample consisted of 25 patients subjected to RYGB and 11 to SG. Body mass index, fat-free mass, fat mass, PhA, serum transthyretin (TTR), albumin, C-reactive protein, alpha-1-acid glycoprotein, and prognostic inflammatory and nutritional indices were evaluated at four time points: before and approximately two, six, and 12 months after RYGB or SG. One-way repeated measures ANOVA or the Friedman test with Tukey's post hoc test was used depending on data distribution. The correlation between PhA and biochemical parameters and indices were evaluated using Spearman's or Pearson's correlation coefficients.

RESULTS

Except for serum albumin, all parameters significantly decreased over time (p < 0.001). Only the RYGB group showed transthyretinTR values below reference ones. Prognostic indices significantly decreased in both groups (p < 0.001). We found a significant positive correlation of PhA with TTR in both RYGB (r = 0.475; p < 0.001) and SG (r = 0.457; p < 0.001).

CONCLUSIONS

Data suggest that at a one-year follow-up after bariatric surgery, lower PhA values might indicate a concomitant loss of visceral protein and a worsening of protein nutritional status.

Fractional Gluconeogenesis: A Biomarker of Dietary Energy Adequacy in a Rat Brain Injury Model

Patients treated for traumatic brain injury (TBI) are in metabolic crises because of the trauma and underfeeding. We utilized fractional gluconeogenesis (fGNG) to assess nutritional adequacy in ad libitum-fed and calorically-restricted rats following TBI. Male Sprague-Dawley individually housed rats 49 days of age were randomly assigned into four groups: ad libitum (AL) fed control (AL-Con, sham), AL plus TBI (AL+TBI), caloric restriction (CR) control (CR-Con, sham), and CR plus TBI (CR+TBI). From days 1-7 animals were given AL access to food and water containing 6% deuterium oxide (D₂O). On day 8, a pre-intervention blood sample was drawn from each animal, and TBI, sham injury, and CR protocols were initiated. On day 22, the animals were euthanized, and blood was collected to measure fGNG. Pre-intervention, there was no significant difference in fGNG among groups (p ≥ 0.05). There was a significant increase in fGNG due to caloric restriction, independent of TBI (p ≤ 0.05). In addition, fGNG may provide a real-time, personalized biomarker for assessing patient dietary caloric needs.

Emerging roles of fibroblast growth factor 21 in critical disease

In spite of the great progress in the management of critical diseases in recent years, its associated prevalence and mortality of multiple organ failure still remain high. As an endocrine hormone, fibroblast growth factor 21 (FGF21) functions to maintain homeostasis in the whole body. Recent studies have proved that FGF21 has promising potential effects in critical diseases. FGF21 has also been found to have a close relationship with the progression of critical diseases and has a great predictive function for organ failure. The level of FGF21 was elevated in both mouse models and human patients with sepsis or other critical illnesses. Moreover, it is a promising biomarker and has certain therapeutic roles in some critical diseases. We focus on the emerging roles of FGF21 and its potential effects in critical diseases including acute lung injury/acute respiratory distress syndrome (ALI/ARDS), acute myocardial injury (AMI), acute kidney injury (AKI), sepsis, and liver failure in this review. FGF21 has high application value and is worth further studying. Focusing on FGF21 may provide a new perspective for the management of the critical diseases.

The emerging roles of next-generation metabolomics in critical care nutrition

Critical illness leads to millions of deaths worldwide each year, with a significant surge due to the COVID-19 pandemic. Patients with critical illness are frequently associated with systemic metabolic disorders and malnutrition. The idea of intervention for critically ill patients through enteral and parenteral nutrition has been paid more and more attention gradually. However, current nutritional therapies focus on evidence-based practice, and there have been lacking holistic approaches for nutritional support assessment. Metabolomics is a well-established omics technique in system biology that enables comprehensive profiling of metabolites in a biological system and thus provides the underlying information expressed and modulated by all other omics layers. In recent years, with the development of high-resolution and accurate mass spectrometry, metabolomics entered a new "generation", promoting its broader applications in critical care nutrition. In this review, we first described the technological development and milestones of next-generation metabolomics in the past 20 years. We then discussed the emerging roles of next-generation metabolomics in advancing our understanding of critical care nutrition, such as nutritional deficiency risk evaluation, metabolic mechanisms of nutritional therapies, and novel nutrition target identification.

Nitrogen Metabolism Disorder Accelerates Occurrence and Development of Lung Adenocarcinoma: A Bioinformatic Analysis and In Vitro Experiments

Background

Nitrogen metabolism (NM) plays a pivotal role in immune regulation and the occurrence and development of cancers. The aim of this study was to construct a prognostic model and nomogram using NM-related genes for the evaluation of patients with lung adenocarcinoma (LUAD).

Methods

The differentially expressed genes (DEGs) related to NM were acquired from The Cancer Genome Atlas (TCGA) database. Consistent clustering analysis was used to divide them into different modules, and differentially expressed genes and survival analysis were performed. The survival information of patients was combined with the expressing levels of NM-related genes that extracted from TCGA and Gene Expression Omnibus (GEO) databases. Subsequently, univariate Cox analysis and the least absolute shrinkage and selection operator (LASSO) regression were used to build a prognostic model. GO and KEGG analysis were elaborated in relation with the mechanisms of NM disorder (NMD). Meanwhile, immune cells and immune functions related to NMD were discussed. A nomogram was built according to the univariate and multivariate Cox analysis to identify independent risk factors. Finally, real-time fluorescent quantitative PCR (RT-PCR) and Western bolt (WB) were used to verify the expression level of hub genes.

Results

There were 138 differential NM-related genes that were divided into two gene modules. Sixteen NM-related genes were used to build a prognostic model and the receiver operating characteristic curve (ROC) showed that the efficiency was reliable. GO and KEGG analysis suggested that NMD accelerated development of LUAD through the Wnt signaling pathway. The level of activated dendritic cells (aDCs) and type II interferon response in the low-risk group was higher than that of the high-risk group. A nomogram was constructed based on ABCC2, HMGA2, and TN stages, which was identified as four independent risk factors. Finally, RT-PCR and WB showed that CDH17, IGF2BP1, IGFBP1, ABCC2, and HMGA2 were differently expressed between human lung fibroblast (HLF) cells and cancer cells.

Conclusions

High NM levels were revealed as a poor prognosis of LUAD. NMD regulates immune system through affecting aDCs and type II interferon response. The prognostic model with NM-related genes could be used to effectively evaluate the outcomes of patients.

Effects of Early Bedside Cycle Exercise on Gastrointestinal Function in Intensive Care Unit Patients Receiving Mechanical Ventilation

Background

A prolonged stay in the intensive care unit (ICU) is associated with gastrointestinal failure, which may have a destructive effect on functional status within 1 year after hospital discharge. The aim was to investigate the effects of a daily exercise session, using a bedside cycle ergometer, on gastrointestinal functions, such as diarrhea, gastric retention, and vomiting, in patients with severe pneumonia who received mechanical ventilation (MV).

Methods

The study was a randomized controlled trial, and its setting was the ICU of a tertiary hospital in Eastern China. A total of 102 critically ill patients who received MV were recruited only when their cardiorespiratory function was deemed stable to perform a bedside cycling exercise. Those patients were expected to spend a minimum of 7 days in the ICU. All subjects received respiratory physiotherapy and performed a daily standardized passive or active motion session of their limbs. The patients were randomized into two groups, namely, the treatment group, which were administered passive or active leg exercise intervention for 20 min/day using a bedside ergometer, and the control group, which did not. Gastrointestinal (GI) functions and the nutritional status of both groups were evaluated on the first, fourth, and seventh days of training and at discharge.

Results

During the 7 days of the study, the number of patients with diarrhea in the treatment group was significantly lower than that in the control group. In contrast, there were significantly more patients in the treatment group with increased bowel sounds (P < 0.05). However, there was no significant difference in the number of patients with vomiting and gastric retention between these two groups. Moreover, when the patients were discharged from the hospital, the albumin level and lymphocyte count were significantly higher in the treatment group (P < 0.05). In addition, the number of invasive ventilation days in the treatment group was less than that in the control group (P < 0.05). While the ICU length of stay and the total hospitalization time were not significantly different between the two groups.

Conclusion

Early exercise training in critical ICU survivors who received MV enhanced the recovery of gastrointestinal functions and improved the patient’s nutrition status at hospital discharge.

A guide to enteral nutrition in intensive care units: 10 expert tips for the daily practice

The preferential use of the oral/enteral route in critically ill patients over gut rest is uniformly recommended and applied. This article provides practical guidance on enteral nutrition in compliance with recent American and European guidelines. Low-dose enteral nutrition can be safely started within 48 h after admission, even during treatment with small or moderate doses of vasopressor agents. A percutaneous access should be used when enteral nutrition is anticipated for ≥ 4 weeks. Energy delivery should not be calculated to match energy expenditure before day 4–7, and the use of energy-dense formulas can be restricted to cases of inability to tolerate full-volume isocaloric enteral nutrition or to patients who require fluid restriction. Low-dose protein (max 0.8 g/kg/day) can be provided during the early phase of critical illness, while a protein target of > 1.2 g/kg/day could be considered during the rehabilitation phase. The occurrence of refeeding syndrome should be assessed by daily measurement of plasma phosphate, and a phosphate drop of 30% should be managed by reduction of enteral feeding rate and high-dose thiamine. Vomiting and increased gastric residual volume may indicate gastric intolerance, while sudden abdominal pain, distension, gastrointestinal paralysis, or rising abdominal pressure may indicate lower gastrointestinal intolerance.

Is Preoperative Serum Albumin Predictive of Adverse Surgical Outcomes in Maxillofacial Fracture Repair?

PURPOSE

Malnutrition has been recognized as a predictor of postoperative adverse outcomes across many surgical subspecialties. The purpose of this study was to evaluate the relationship between serum albumin and adverse outcomes in patients undergoing operative repair of maxillofacial fractures.

METHODS

The authors utilized the 2011 to 2018 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) databases to identify patients with facial fractures undergoing operative repair. The primary predictor variable was preoperative serum albumin level. Outcome variables included complications and other adverse outcomes occurring within 30 days of the index operation. Descriptive, bivariate, and multiple logistic regression statistics were utilized to evaluate the relationship between serum albumin and adverse outcomes.

RESULTS

During the study period 1211 subjects underwent operative repair of a facial fracture and had a documented serum albumin level. Of these subjects, 1037 (85.6%) had normal albumin levels and 174 (14.4%) had hypoalbuminemia. A total of 90 subjects experienced a complication (7.43%), although albumin level was not associated with surgical complications or any complication. In bivariate analysis, subjects with hypoalbuminemia were significantly more likely to have an extended length of stay (P ≤ .001), adverse discharge disposition (P ≤ .001), and be readmitted (P = .002). In multivariate analysis, hypoalbuminemia was an independent predictor of an extended length of stay (P ≤ .001, 95% CI 2.50 to 7.62), adverse discharge disposition (P = .048, 95% CI 1.01 to 3.75), and readmission (P = .041, 95% CI 1.03 to 3.47).

CONCLUSIONS

Serum albumin was not an independent predictor of complications after maxillofacial trauma repair. However, it was an independent predictor of other adverse outcomes including extended length of stay, adverse discharge disposition, and readmission. Targeted nutritional optimization may represent an opportunity to improve outcomes in this demographic.

Wearable and Mobile Sensors for Personalized Nutrition

While wearable and mobile chemical sensors have experienced tremendous growth over the past decade, their potential for tracking and guiding nutrition has emerged only over the past three years. Currently, guidelines from doctors and dietitians represent the most common approach for maintaining optimal nutrition status. However, such recommendations rely on population averages and do not take into account individual variability in responding to nutrients. Precision nutrition has recently emerged to address the large heterogeneity in individuals' responses to diet, by tailoring nutrition based on the specific requirements of each person. It aims at preventing and managing diseases by formulating personalized dietary interventions to individuals on the basis of their metabolic profile, background, and environmental exposure. Recent advances in digital nutrition technology, including calories-counting mobile apps and wearable motion tracking devices, lack the ability of monitoring nutrition at the molecular level. The realization of effective precision nutrition requires synergy from different sensor modalities in order to make timely reliable predictions and efficient feedback. This work reviews key opportunities and challenges toward the successful realization of effective wearable and mobile nutrition monitoring platforms. Non-invasive wearable and mobile electrochemical sensors, capable of monitoring temporal chemical variations upon the intake of food and supplements, are excellent candidates to bridge the gap between digital and biochemical analyses for a successful personalized nutrition approach. By providing timely (previously unavailable) dietary information, such wearable and mobile sensors offer the guidance necessary for supporting dietary behavior change toward a managed nutritional balance. Coupling of the rapidly emerging wearable chemical sensing devices-generating enormous dynamic analytical data-with efficient data-fusion and data-mining methods that identify patterns and make predictions is expected to revolutionize dietary decision-making toward effective precision nutrition.

Micronutrients early in critical illness, selective or generous, enteral or intravenous?

PURPOSE OF REVIEW

Micronutrients have essential antioxidant and immune functions, while low blood concentrations are frequently observed in critically ill patients. This has led to the concepts of complementation, repletion, or even pharmacological supplementation. Over the last three decades, many clinical studies have tested the latter strategy, with controversial or negative results. Therefore, this review aims at evaluating micronutrient-related interventions that are mandatory or need to be assessed in future trials or clinical registries in all or specific critically ill patients.

RECENT FINDINGS

In the critically ill, low plasma/serum micronutrient levels not always reflect a true deficiency in the absence of demonstrable losses. Current practices of micronutrient provision and monitoring in critical care, vary substantially across the world. Also, recent clinical trials testing high dose as monotherapy (selenium, thiamine, vitamin C, vitamin D) or in combination have failed to demonstrate clinical benefits in sepsis. However, these studies have not applied a physiological integrative approach of micronutrient action.

SUMMARY

Micronutrients are essential in nutrition but their administration and monitoring are difficult. So far, different well designed RCTs on intravenous and oral high dose micronutrient supplementation have been conducted. Nevertheless, very high-dose single micronutrients cannot be advocated at this stage in sepsis, or any other critical condition. By contrast, studies using combination of moderate doses of micronutrients in specific diseases, such as burns and trauma have been associated with improved outcomes. Intravenous administration seems to be the most efficient route. Future clinical trials need to integrate the physiology underlying the interconnected micronutrient activity, and choose more specific primary and secondary endpoints.

Trial Design in Critical Care Nutrition: The Past, Present and Future

The specialty of nutrition in critical care is relatively modern, and accordingly, trial design has progressed over recent decades. In the past, small observational and physiological studies evolved to become small single-centre comparative trials, but these had significant limitations by today’s standards. Power calculations were often not undertaken, outcomes were not specified a priori, and blinding and randomisation were not always rigorous. These trials have been superseded by larger, more carefully designed and conducted multi-centre trials. Progress in trial conduct has been facilitated by a greater understanding of statistical concepts and methodological design. In addition, larger numbers of potential study participants and increased access to funding support trials able to detect smaller differences in outcomes. This narrative review outlines why critical care nutrition research is unique and includes a historical critique of trial design to provide readers with an understanding of how and why things have changed. This review focuses on study methodology, population group, intervention, and outcomes, with a discussion as to how these factors have evolved, and concludes with an insight into what we believe trial design may look like in the future. This will provide perspective on the translation of the critical care nutrition literature into clinical practice.

Marked losses of computed tomography-derived skeletal muscle area and density over the first month of a critical illness are not associated with energy and protein delivery

OBJECTIVES

Changes in muscularity during different phases of critical illness are not well described. This retrospective study aimed to describe changes in computed tomography (CT)-derived skeletal muscle area (SMA) and density (SMD) across different weeks of critical illness and investigate associations between changes in these parameters and energy and protein delivery.

METHODS

Thirty-two adults admitted to the intensive care unit (ICU) who had ≥2 CT scans at the third lumbar area performed ≥7 d apart were included in the study. CT-derived SMA (cm²) and SMD (Hounsfield units) were determined using specialized software. A range of clinical and nutrition variables were collected for each day between comparator scans. Associations were assessed by Pearson or Spearman correlations.

RESULTS

There was a significant decrease in SMA between the two comparator scans where the first CT scan was performed in ICU wk 1 (n = 20; P < .001), wk 2 (n = 11; P < .007), and wk 3 to 4 (n = 7; P = .012). There was no significant change in SMA beyond ICU wk 5 to 7 (P = .943). A significant decline in SMD was observed across the first 3 wk of ICU admission (P < .001). Overall, patients received a mean 24 ± 6 kcal energy/kg and 1.1 ± 0.4 g protein/kg per study day and 83% of energy and protein requirements according to dietitian estimates. No association between SMA or SMD changes and nutrition delivery were found.

CONCLUSIONS

Critically ill patients experience marked losses of SMA over the first month of critical illness, attenuated after wk 5 to 7. Energy and protein delivery were not associated with degree of muscle loss.

First international meeting of early career investigators: Current opportunities, challenges and horizon in critical care nutrition research

BACKGROUND

Appropriate nutritional support is a key component of care for critically ill patients. While malnutrition increases complications, impacting long term outcomes and healthcare-related costs, uncertainties persist regarding optimal provision of nutritional support in this setting.

METHODS

An international group of healthcare providers (HCPs) from critical care specialties and nutrition researchers convened to identify knowledge gaps and learnings from studies in critical care nutrition. Clinical research needs were identified in order to better inform future nutrition practices.

RESULTS

Challenges in critical care nutrition arise, in part, from inconsistent outcomes in several large-scale studies regarding the optimal amount of calories and protein to prescribe, the optimal time to initiate nutritional support and the role of parental nutrition to support critically ill patients. Furthermore, there is uncertainty on how best to identify patients at nutritional risk, and the appropriate outcome measures for ICU nutrition studies. Given HCPs have a suboptimal evidence base to inform the nutritional management of critically ill patients, further well-designed clinical trials capturing clinically relevant endpoints are needed to address these knowledge gaps.

CONCLUSIONS

The identified aspects for future research could be addressed in studies designed and conducted in collaboration with an international team of interdisciplinary nutrition experts. The aim of this collaboration is to address the unmet need for robust clinical data needed to develop high-quality evidence-based nutritional intervention recommendations to better inform the future management of critically ill patients.