Initial trophic vs full enteral feeding in patients with acute lung injury: the EDEN randomized trial

A comparison of computational algorithms for the Bayesian analysis of clinical trials

BACKGROUND

Clinical trials are increasingly using Bayesian methods for their design and analysis. Inference in Bayesian trials typically uses simulation-based approaches such as Markov Chain Monte Carlo methods. Markov Chain Monte Carlo has high computational cost and can be complex to implement. The Integrated Nested Laplace Approximations algorithm provides approximate Bayesian inference without the need for computationally complex simulations, making it more efficient than Markov Chain Monte Carlo. The practical properties of Integrated Nested Laplace Approximations compared to Markov Chain Monte Carlo have not been considered for clinical trials. Using data from a published clinical trial, we aim to investigate whether Integrated Nested Laplace Approximations is a feasible and accurate alternative to Markov Chain Monte Carlo and provide practical guidance for trialists interested in Bayesian trial design.

METHODS

Data from an international Bayesian multi-platform adaptive trial that compared therapeutic-dose anticoagulation with heparin to usual care in non-critically ill patients hospitalized for COVID-19 were used to fit Bayesian hierarchical generalized mixed models. Integrated Nested Laplace Approximations was compared to two Markov Chain Monte Carlo algorithms, implemented in the software JAGS and stan, using packages available in the statistical software R. Seven outcomes were analysed: organ-support free days (an ordinal outcome), five binary outcomes related to survival and length of hospital stay, and a time-to-event outcome. The posterior distributions for the treatment and sex effects and the variances for the hierarchical effects of age, site and time period were obtained. We summarized these posteriors by calculating the mean, standard deviations and the 95% equitailed credible intervals and presenting the results graphically. The computation time for each algorithm was recorded.

RESULTS

The average overlap of the 95% credible interval for the treatment and sex effects estimated using Integrated Nested Laplace Approximations was 96% and 97.6% compared with stan, respectively. The graphical posterior densities for these effects overlapped for all three algorithms. The posterior mean for the variance of the hierarchical effects of age, site and time estimated using Integrated Nested Laplace Approximations are within the 95% credible interval estimated using Markov Chain Monte Carlo but the average overlap of the credible interval is lower, 77%, 85.6% and 91.3%, respectively, for Integrated Nested Laplace Approximations compared to stan. Integrated Nested Laplace Approximations and stan were easily implemented in clear, well-established packages in R, while JAGS required the direct specification of the model. Integrated Nested Laplace Approximations was between 85 and 269 times faster than stan and 26 and 1852 times faster than JAGS.

CONCLUSION

Integrated Nested Laplace Approximations could reduce the computational complexity of Bayesian analysis in clinical trials as it is easy to implement in R, substantially faster than Markov Chain Monte Carlo methods implemented in JAGS and stan, and provides near identical approximations to the posterior distributions for the treatment effect. Integrated Nested Laplace Approximations was less accurate when estimating the posterior distribution for the variance of hierarchical effects, particularly for the proportional odds model, and future work should determine if the Integrated Nested Laplace Approximations algorithm can be adjusted to improve this estimation.

Clinical phenotype of ARDS based on K-means cluster analysis: A study from the eICU database

Purpose

To explore the characteristics of the clinical phenotype of ARDS based on Machine Learning.

Methods

This is a study on Machine Learning. Screened cases of acute respiratory distress syndrome (ARDS) in the eICU database collected basic information in the cases and clinical data on the Day 1, Day 3, and Day 7 after the diagnosis of ARDS, respectively. Using the Calinski-Harabasz criterion, Gap Statistic, and Silhouette Coefficient, we determine the optimal clustering number k value. By the K-means cluster analysis to derive clinical phenotype, we analyzed the data collected within the first 24 h. We compared it with the survival of cases under the Berlin standard classification, and also examined the phenotypic conversion within the first 24 h, on day 3, and on day 7 after the diagnosis of ARDS.

Results

We collected 5054 cases and derived three clinical phenotypes using K-means cluster analysis. Phenotype-I is characterized by fewer abnormal laboratory indicators, higher oxygen partial pressure, oxygenation index, APACHE IV score, systolic and diastolic blood pressure, and lower respiratory rate and heart rate. Phenotype-II is characterized by elevated white blood cell count, blood glucose, creatinine, temperature, heart rate, and respiratory rate. Phenotype-III is characterized by elevated age, partial pressure of carbon dioxide, bicarbonate, GCS score, albumin. The differences in ICU length of stay and in-hospital mortality were significantly different between the three phenotypes (P < 0.05), with phenotype I having the lowest in-hospital mortality (10 %) and phenotype II having the highest (31.8 %). To compare the survival analysis of ARDS patients classified by phenotype and those classified according to Berlin criteria. The results showed that the differences in survival between phenotypes were statistically significant (P < 0.05) under phenotypic classification.

Conclusions

The clinical classification of ARDS based on K-means clustering analysis is beneficial for further identifying ARDS patients with different characteristics. Compared to the Berlin standard, the new clinical classification of ARDS provides a clearer display of the survival status of different types of patients, which helps to predict patient prognosis.

Personalized Nutrition in the Pediatric ICU: Steering the Shift from Acute Stress to Metabolic Recovery and Rehabilitation

BACKGROUND

Nutrition significantly impacts the outcomes of critically ill children in intensive care units (ICUs). Due to the evolving metabolic, neuroendocrine, and immunological disorders associated with severe illness or trauma, there are dynamically changing phases of energy needs requiring tailored macronutrient intake.

OBJECTIVES

This study aims to assess the changing dietary needs from the acute phase through recovery, provide recommendations for implementing evidence-based strategies to ensure adequate energy and nutrient provision in pediatric ICUs, and optimize patient outcomes.

METHODS

A comprehensive search of the MEDLINE-PubMed database was conducted, focusing on randomized controlled trials, meta-analyses, and systematic reviews related to the nutrition of critically ill children. The study highlights recent guidelines using the GRADE approach, supplemented by relevant adult studies, current clinical practices, challenges, gaps in knowledge, and future directions for research aimed at improving nutritional interventions.

RESULTS

Early personalized, incremental enteral feeding helps mitigate the negative energy balance during the acute phase, aids organ function restoration in the stabilization phase, and supports growth during the recovery phase and beyond. Conversely, early full nutritional support, high protein doses, or isolated micronutrient administration have not demonstrated benefits due to anabolic resistance in these patients. Moreover, early parenteral nutrition during the acute phase may suppress autophagy and lead to worse outcomes. Accurate assessment of nutritional status and monitoring of daily energy and protein needs are crucial.

CONCLUSIONS

Strong evidence supports the establishment of a dedicated nutritional team and the implementation of individualized nutritional protocols in the ICU to reduce morbidity and mortality in critically ill children.

Six-month outcomes after traumatic brain injury in the Augmented versus Routine Approach to Giving Energy multicentre, double-blind, randomised controlled Trial (TARGET)

BACKGROUND

Critically ill patients with a traumatic brain injury (TBI) may require prolonged intensive care unit (ICU) admission and hence receive greater exposure to hospital enteral nutrition. It is unknown if augmented energy delivery with enteral nutrition during ICU admission impacts quality of life in survivors or gastrointestinal tolerance during nutrition delivery in the ICU.

OBJECTIVES

The objective of this study was to compare health-related quality of life, using the EuroQol five-dimensions five-level visual analogue scale at 6 months, in survivors who presented with a TBI and received augmented energy (1.5 kcal/ml) to those who received routine energy (1.0 kcal/ml). Secondary objectives were to explore differences in total energy and protein delivery, gastrointestinal tolerance, and mortality between groups.

METHODS

Secondary analysis of participants admitted with a TBI in the Augmented versus Routine Approach to Giving Energy Trial (TARGET) randomised controlled trial. Data are represented as n (%) or median (interquartile range).

RESULTS

Of the 3957 patients in TARGET, 231 (5.8%) were admitted after a TBI (augmented = 124; routine = 107). Patients within TARGET who were admitted with a TBI were relatively young (42 [27, 61] years) and received TARGET enteral nutrition for an extended period (9 [5, 15] days). At 6 months, EuroQol five-dimensions five-level quality-of-life scores were available for 166 TBI survivors (72% of TBI cohort randomised, augmented = 97, routine = 69). There was no evidence of a difference in quality of life (augmented = 70 [52, 90]; routine = 70 [55, 85]; median difference augmented vs routine = 0 [95% confidence interval: -5, 10]). TBI participants assigned to augmented energy received more energy with a similar protein than the routine group. Gastrointestinal tolerance was similar between groups.

CONCLUSION

While patients admitted after a TBI received enteral nutrition for an extended period, an increased exposure to augmented energy did not affect survivors' quality-of-life scores.

Statistical Power and Performance of Strategies to Analyze Composites of Survival and Duration of Ventilation in Clinical Trials

BACKGROUND

Patients with acute hypoxemic respiratory failure are at high risk of death and prolonged time on the ventilator. Interventions often aim to reduce both mortality and time on the ventilator. Many methods have been proposed for analyzing these endpoints as a single composite outcome (days alive and free of ventilation), but it is unclear which analytical method provides the best performance. Thus, we aimed to determine the analysis method with the highest statistical power for use in clinical trials.

METHODS

Using statistical simulation, we compared multiple methods for analyzing days alive and free of ventilation: the t, Wilcoxon rank-sum, and Kryger Jensen and Lange tests, as well as the proportional odds, hurdle-Poisson, and competing risk models. We compared 14 scenarios relating to: 1) varying baseline distributions of mortality and duration of ventilation, which were based on data from a registry of patients with acute hypoxemic respiratory failure and 2) the varying effects of treatment on mortality and duration of ventilation.

RESULTS AND CONCLUSIONS

All methods have good control of type 1 error rates (i.e., avoid false positive findings). When data are simulated using a proportional odds model, the t test and ordinal models have the highest relative power (92% and 90%, respectively), followed by competing risk models. When the data are simulated using survival models, the competing risk models have the highest power (100% and 92%), followed by the t test and a ten-category ordinal model. All models struggled to detect the effect of the intervention when the treatment only affected one of mortality and duration of ventilation. Overall, the best performing analytical strategy depends on the respective effects of treatment on survival and duration of ventilation and the underlying distribution of the outcomes. The evaluated models each provide a different interpretation for the treatment effect, which must be considered alongside the statistical power when selecting analysis models.

Nutrition practices in Australia and New Zealand in response to evolving evidence: Results of three point-prevalence audits

BACKGROUND

The Augmented versus Routine Approach to Giving Energy Trial (TARGET) was a 4000-patient trial in which augmented enteral calorie dose did not influence outcomes.

AIM

We aimed to quantify practice change following TARGET.

METHODS

Three single-day, prospective, multicentre, point-prevalence audits of adult patients receiving enteral nutrition (EN) in participating Australian and New Zealand intensive care units at 10:00 AM were conducted: (i) 2010 (before conducting TARGET); (ii) 2018 (immediately before publishing TARGET results); and (iii) 2020 (2 years after TARGET publication). Data included baseline characteristics, clinical outcomes, and nutrition data. Data are n (%), mean ± standard deviation, or median [interquartile range]. Differences in enteral calorie prescription between 2018 and 2020 were compared using the Mann-Whitney test.

RESULTS

The percentage of patients receiving EN (2010 42%, 2018 38%, 2020 33%; P = 0.012) and the prescription of calorie-dense EN formula (≥1.5 kcal/ml) (2010 33%, 2018 24%, 2020 23%; P = 0.038) decreased over time. However, when comparing prepublication and postpublication (2018-2020), calorie dose and calorie density were similar: 22.9 ± 8.6 versus 23.4 ± 12.8 kcal/kg/day (P = 0.816) and <1.5 kcal/ml: 76 versus 77% (P = 0.650), respectively.

CONCLUSION

In Australian and New Zealand intensive care units, enteral calorie dose and calorie density of prescribed EN were similar before TARGET publication and 2 years later.

[The role of the musculoadipose status in the assessment of the risk profile before liver transplantation]

Sarcopenia and sarcopenic obesity worsen the prognosis after liver transplantation; however, the assessment of body composition is not yet considered in the evaluation prior to liver transplantation to estimate the risk profile of the recipient. Prehabilitation, which includes the nutritional supplementation and physiotherapy, represents a recent focus of interest in clinical transplantation research. This article gives an overview of the recent knowledge about the role of the musculoadipose status and the available methods for the estimation in the assessment of the recipient's risk profile.

Optimal energy provision early in ICU stay for critically ill patients receiving parenteral nutrition

BACKGROUND

Literature on optimal energy provision via parenteral nutrition (PN) is limited and the evidence quality is low. The purpose of this study is to determine if there is a difference in outcomes in adult critically ill patients when receiving lower vs higher calorie provision via PN early in intensive care unit (ICU) stay.

METHODS

Adult patients initiated on PN within the first 10 days of ICU stay from May 2014 to June 2021 were included in this retrospective study. The primary outcome was to determine the impact of lower (<20 kcal/kg/day) vs higher (>25 kcal/kg/day) calorie provision on all-cause, in-hospital mortality. Secondary outcomes were to determine the impact of calorie provision on hospital or ICU length of stay and incidence of complications.

RESULTS

This study included 133 patients: a lower calorie provision group (n = 77) and a higher calorie provision group (n = 56). There was a significant difference in all-cause, in-hospital mortality between the lower and the higher calorie provision groups (36.36% and 17.86%, respectively; P = 0.02). However, upon a multivariate analysis of death at discharge, the specific calorie provision group did not affect the probability of death at hospital discharge. The secondary outcomes were not significantly different between groups.

CONCLUSION

When comparing lower calorie provision with higher calorie provision in adult critically ill patients receiving PN early within their ICU stay, there were no differences in outcomes after controlling for significant confounders. Future larger prospective studies should further evaluate optimal caloric provision via PN in this population.

Effects of early enteral nutrition on persistent inflammation, immunosuppression, and catabolism syndrome in critically ill patients: A claims database study using a propensity score analysis

BACKGROUND & AIMS

Early enteral nutrition (EEN) potentially improves immune-related outcomes via the maintenance of intestinal immunity; however, the effects of EEN on clinical outcomes, including infectious complications, are controversial. Therefore, we herein investigated whether EEN affected persistent inflammation, immunosuppression, and catabolism syndrome (PICS), which represents the immunocompromised state after critical illness.

METHODS

This retrospective cohort study utilized the administrative claims database of inpatients and laboratory findings. Patients admitted to and treated in the intensive care unit (ICU) for more than 3 consecutive days were included. The primary outcome, a composite of PICS or mortality on day 14 after admission, was compared between the EEN group, which received enteral nutrition (EN) on the first 3 days (day 0, 1, or 2), and the late enteral nutrition (LEN) group, which did not receive EN on the first 3 days, but then received EN on days 3 through 7, using a propensity score-matched analysis. Secondary outcomes included the composite outcome on day 28, in-hospital mortality, the Barthel index, and laboratory data. Patients who met at least two of the following conditions were diagnosed with PICS: CRP >2.0 mg/dL, albumin <3.0 g/dL, and a lymphocyte count <800/μL.

RESULTS

A total of 7530 matched pairs were generated after propensity score matching. The primary outcome was significantly lower in the EEN group (risk difference -3.0%, 95% confidence interval (CI) -4.5 to -1.4%), whereas mortality did not significantly differ. The 28-day composite outcome was similar in the 2 groups (risk difference -1.5%, 95% CI -2.8% to -0.2%, no significant difference in mortality). There was no significant difference in in-hospital mortality between the EEN and LEN groups; however, the Barthel index at discharge was higher in the EEN group (the medians, 50 vs 45, P = 0.001). Laboratory data showed lower Albumin and CRP on day 14 in the EEN group, but no other significant differences.

CONCLUSIONS

In patients admitted to the ICU, EEN was associated with a lower incidence of PICS on days 14 and 28, but was not associated with mortality. This positive association was not observed in sepsis, cardiac diseases, or gastrointestinal diseases.

Nutrition in the intensive care unit: from the acute phase to beyond

Recent randomized controlled trials (RCTs) have shown no benefit but  dose-dependent harm by early full nutritional support in critically ill patients. Lack of benefit may be explained by anabolic resistance, suppression of cellular repair processes, and aggravation of hyperglycemia and insulin needs. Also early high amino acid doses did not provide benefit, but instead associated with harm in patients with organ dysfunctions. However, most studies focused on nutritional interventions initiated during the first days after intensive care unit admission. Although the intervention window of some RCTs extended into the post-acute phase of critical illness, no large RCTs studied nutritional interventions initiated beyond the first week. Hence, clear evidence-based guidance on when and how to initiate and advance nutrition is lacking. Prolonged underfeeding will come at a price as there is no validated metabolic monitor that indicates readiness for medical nutrition therapy, and an adequate response to nutrition, which likely varies between patients. Also micronutrient status cannot be assessed reliably, as inflammation can cause redistribution, so that plasma micronutrient concentrations are not necessarily reflective of total body stores. Moreover, high doses of individual micronutrients have not proven beneficial. Accordingly, current evidence provides clear guidance on which nutritional strategies to avoid, but the ideal nutritional regimen for individual patients remains unclear. In this narrative review, we summarize the findings of recent studies, discuss possible mechanisms explaining the results, point out pitfalls in interpretation of RCTs and their effect on clinical practice, and formulate suggestions for future research.

Dietary patterns and micronutrients in respiratory infections including COVID-19: a narrative review

BACKGROUND

COVID-19 is a pandemic caused by nCoV-2019, a new beta-coronavirus from Wuhan, China, that mainly affects the respiratory system and can be modulated by nutrition.

METHODS

This review aims to summarize the current literature on the association between dietary intake and serum levels of micronutrients, malnutrition, and dietary patterns and respiratory infections, including flu, pneumonia, and acute respiratory syndrome, with a focus on COVID-19. We searched for relevant articles in various databases and selected those that met our inclusion criteria.

RESULTS

Some studies suggest that dietary patterns, malnutrition, and certain nutrients such as vitamins D, E, A, iron, zinc, selenium, magnesium, omega-3 fatty acids, and fiber may have a significant role in preventing respiratory diseases, alleviating symptoms, and lowering mortality rates. However, the evidence is not consistent and conclusive, and more research is needed to clarify the mechanisms and the optimal doses of these dietary components. The impact of omega-3 and fiber on respiratory diseases has been mainly studied in children and adults, respectively, and few studies have examined the effect of dietary components on COVID-19 prevention, with a greater focus on vitamin D.

CONCLUSION

This review highlights the potential of nutrition as a modifiable factor in the prevention and management of respiratory infections and suggests some directions for future research. However, it also acknowledges the limitations of the existing literature, such as the heterogeneity of the study designs, populations, interventions, and outcomes, and the difficulty of isolating the effects of single nutrients from the complex interactions of the whole diet.

Con - The Harms of Overfeeding Early in Critical Illness

Historically, several studies showed an association between malnutrition in critically ill patients and poor outcomes. As a result, the standard practice had been to provide patients with full nutrition as soon as possible to eliminate malnutrition, improve outcomes, and reduce mortality. However, several studies recently suggested that providing more calories and protein is not better in critical illness and may be harmful in certain disease states. This literature review and editorial describe the harms of maximal feeding early in critical illness.

Nutritional support for the trauma and emergency general surgery patient: What you need to know

ABSTRACT

Decades of research have provided insight into the benefits of nutritional optimization in the elective surgical patient. Patients who are nutritionally prepared for surgery enjoy reduced length of hospital and intensive care unit stays and suffer fewer complications. In the trauma and emergency general surgery patient populations, we are not afforded the preoperative period of optimization and patients often suffer longer lengths of hospital stay, discharge to nonhome destinations, and higher infectious and mortality rates. Nonetheless, ongoing research in this vulnerable and time critical diagnosis population has revealed significant outcomes benefits with the meticulous nutritional support of these patients. However, it is important to note that optimal nutritional support in this challenging patient population is not simply a matter of "feeding more and feeding earlier." In this review, we will address assessing nutritional needs, the provision of optimal nutrition, the timing and route of nutrition, and monitoring outcomes and discuss the management of nutrition in the complex trauma and emergency general surgery patient.

LEVEL OF EVIDENCE

Literature Synthesis and Expert Opinion; Level V.

Identifying novel clinical phenotypes of acute respiratory distress syndrome using trajectories of daily fluid balance: a secondary analysis of randomized controlled trials

BACKGROUND

Previously identified phenotypes of acute respiratory distress syndrome (ARDS) could not reveal the dynamic change of phenotypes over time. We aimed to identify novel clinical phenotypes in ARDS using trajectories of fluid balance, to test whether phenotypes respond differently to different treatment, and to develop a simplified model for phenotype identification.

METHODS

FACTT (conservative vs liberal fluid management) trial was classified as a development cohort, joint latent class mixed models (JLCMMs) were employed to identify trajectories of fluid balance. Heterogeneity of treatment effect (HTE) for fluid management strategy across phenotypes was investigated. We also constructed a parsimonious probabilistic model using baseline data to predict the fluid trajectories in the development cohort. The trajectory groups and the probabilistic model were externally validated in EDEN (initial trophic vs full enteral feeding) trial.

RESULTS

Using JLCMM, we identified two trajectory groups in the development cohort: Class 1 (n = 758, 76.4% of the cohort) had an early positive fluid balance, but achieved negative fluid balance rapidly, and Class 2 (n = 234, 24.6% of the cohort) was characterized by persistent positive fluid balance. Compared to Class 1 patients, patients in Class 2 had significantly higher 60-day mortality (53.5% vs. 17.8%, p < 0.001), and fewer ventilator-free days (0 vs. 20, p < 0.001). A significant HTE between phenotypes and fluid management strategies was observed in the FACTT. An 8-variables model was derived for phenotype assignment.

CONCLUSIONS

We identified and validated two novel clinical trajectories for ARDS patients, with both prognostic and predictive enrichment. The trajectories of ARDS can be identified with simple classifier models.

Early goal enteral nutrition associated with decreased in-hospital death in mechanically ventilated critically ill adults: a retrospective cohort study

INTRODUCTION

Early enteral nutrition (EN) in critically ill adult patients is thought to improve mortality and morbidity; expert guidelines recommend early initiation of EN in critically ill adults. However, the ideal schedule and dose of EN remain understudied.

STUDY OBJECTIVE

Our objective was to evaluate the relationship between achieving 70% of recommended EN within 2 days of intubation ('early goal EN') and clinical outcomes in mechanically ventilated medically critically ill adults. We hypothesised that early goal EN would be associated with reduced in-hospital death.

METHODS

We conducted a retrospective cohort study of mechanically ventilated adult patients admitted to our medical intensive care unit during 2013-2019. We assessed the proportion of recommended total EN provided to the patient each day following intubation until extubation, death or 7 days whichever was shortest. Patients who received 70% or more of their recommended total daily EN within 2 days of intubation (ie, 'baseline period') were considered to have achieved 'early goal EN'; these patients were compared with patients who did not ('low EN'). The primary outcome was in-hospital death; secondary outcomes were successful extubation and discharge alive.

RESULTS

938 patients met eligibility criteria and survived the baseline period. During the 7-day postintubation period, 64% of all patients reached 70% of recommended daily calories; 33% of patients achieved early goal EN. In unadjusted and adjusted models, early goal EN versus low EN was associated with a lower incidence of in-hospital death (subdistribution HR (SHR) unadjusted=0.63, p=0.0003, SHR adjusted=0.73, p=0.02). Early goal EN was also associated with a higher incidence of successful extubation (SHR unadjusted=1.41, p<0.00001, SHR adjusted=1.27, p=0.002) and discharge alive (SHR unadjusted=1.54, p<0.00001, SHR adjusted=1.24, p=0.02).

CONCLUSIONS

Early goal EN was associated with significant improvement in clinical metrics of decreased in-hospital death, increased extubation and increased hospital discharge alive.

Trophic Nutrition in ICU Patients Undergoing High-Flow Oxygen Therapy and/or Noninvasive Mechanical Ventilation: The Nutri-Trophic Study

Enteral nutrition (EN) therapy in ICU patients requiring oxygen therapy with high-flow nasal cannula (HFNC) and/or noninvasive mechanical ventilation (NIMV) is controversial. A prospective, cohort, observational, and multicenter study was conducted in 10 ICUs in Spain to analyze the 90-day mortality, tolerance, side effects, and infectious complications of trophic EN in patients requiring HFNC therapy and/or NIVM. A total of 149 patients were enrolled. The mean age, severity scores, tracheobronchitis, bacteremia, and antimicrobial therapy were significantly higher in deceased than in living patients (p < 0.05), and the mortality rate was 14.8%. A total of 110 patients received oral trophic feedings, 36 patients received nasogastric tube feedings (NGFs), and 3 received mixed feedings. Trophic EN was discontinued in only ten (14.9%) patients because of feeding-related complications. The variables selected for the multivariate logistic regression on feeding discontinuation were SOFA upon admission (OR per unit = 1.461) and urea (OR per mg/dL = 1.029). There were no significant differences in the development of new infections according to the route of EN administration. Early trophic feeding administered to patients with acute respiratory failure requiring noninvasive ventilation is safe and feasible, and is associated with few dietary and infectious complications in a mortality, setting comparable to similar studies.

Early enteral nutrition in patients with out-of-hospital cardiac arrest under target temperature management was associated with a lower 7-day bacteremia rate: A post-hoc analysis of a retrospective cohort study

INTRODUCTION

Early enteral nutrition (EN) is a nutritional strategy for reducing the incidence of in-hospital infections. However, the benefits of early EN, under targeted temperature management (TTM) in patients with out-of-hospital cardiac arrest (OHCA), remain unclear. We aimed to evaluate the effect of early EN on the infective complications of OHCA patients who underwent TTM.

METHODS

We retrospectively searched the clinical databases of two adult emergency tertiary referral hospitals in southern Taiwan and identified patients admitted for OHCA who underwent TTM between 2017 and 2022. The 85 enrolled patients were divided into two groups based on timing: early EN (EN within 48 h of admission) and delayed EN (EN > 48 h after admission). Clinical outcomes of 7-day infective complications between the two groups were analyzed.

RESULTS

Early EN was provided to 57 (67 %) of 85 patients and delayed EN was provided to the remaining 28 (33 %) patients. No significant differences in baseline patient characteristics were observed between the two groups. In addition, no differences in clinical outcomes were observed, except that the early EN group had a lower 7-day bacteremia rate (5.3 % vs. 26.9 %, p = 0.013). Gram-negative bacteria were the major pathogen among the 7-day infective complications.

CONCLUSION

In OHCA patients treated with TTM, early EN was associated with a lower 7-day bacteremia rate. Furthermore, the application of early EN in this population was well tolerated without significant adverse events.

Nutritional Support in Critically Ill Trauma Patients

Enteral nutrition should be initiated within 24 to 48 hours of injury, starting at a trophic rate and increasing to goal rate after hemodynamic stability is achieved. The modified Nutritional Risk in the Critically Ill score can help identify patients who will benefit most from aggressive and early nutritional intervention. In the first week of critical illness, the patient should receive only 70% to 80% of estimated calories and protein should be targeted to 1.5 to 2 g/kg. Parenteral nutrition can be provided safely without increased adverse events. Peri-operative (and intra-operative) feeding has been shown to be safe in selected patients.

The role of fatty acid metabolism in acute lung injury: a special focus on immunometabolism

Reputable evidence from multiple studies suggests that excessive and uncontrolled inflammation plays an indispensable role in mediating, amplifying, and protracting acute lung injury (ALI). Traditionally, immunity and energy metabolism are regarded as separate functions regulated by distinct mechanisms, but recently, more and more evidence show that immunity and energy metabolism exhibit a strong interaction which has given rise to an emerging field of immunometabolism. Mammalian lungs are organs with active fatty acid metabolism, however, during ALI, inflammation and oxidative stress lead to a series metabolic reprogramming such as impaired fatty acid oxidation, increased expression of proteins involved in fatty acid uptake and transport, enhanced synthesis of fatty acids, and accumulation of lipid droplets. In addition, obesity represents a significant risk factor for ALI/ARDS. Thus, we have further elucidated the mechanisms of obesity exacerbating ALI from the perspective of fatty acid metabolism. To sum up, this paper presents a systematical review of the relationship between extensive fatty acid metabolic pathways and acute lung injury and summarizes recent advances in understanding the involvement of fatty acid metabolism-related pathways in ALI. We hold an optimistic believe that targeting fatty acid metabolism pathway is a promising lung protection strategy, but the specific regulatory mechanisms are way too complex, necessitating further extensive and in-depth investigations in future studies.

The Relationship Between Metabolic Syndrome and Mortality Among Patients With Acute Respiratory Distress Syndrome in Acute Respiratory Distress Syndrome Network and Prevention and Early Treatment of Acute Lung Injury Network Trials

OBJECTIVES

Metabolic syndrome is known to predict outcomes in COVID-19 acute respiratory distress syndrome (ARDS) but has never been studied in non-COVID-19 ARDS. We therefore aimed to determine the association of metabolic syndrome with mortality among ARDS trial subjects.

DESIGN

Retrospective cohort study of ARDS trials' data.

SETTING

An ancillary analysis was conducted using data from seven ARDS Network and Prevention and Early Treatment of Acute Lung Injury Network randomized trials within the Biologic Specimen and Data Repository Information Coordinating Center database.

PATIENTS

Hospitalized patients with ARDS and metabolic syndrome (defined by obesity, diabetes, and hypertension) were compared with similar patients without metabolic syndrome (those with less than three criteria).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was 28-day mortality. Among 4288 ARDS trial participants, 454 (10.6%) with metabolic syndrome were compared with 3834 controls (89.4%). In adjusted analyses, the metabolic syndrome group was associated with lower 28-day and 90-day mortality when compared with control (adjusted odds ratio [aOR], 0.70 [95% CI, 0.55-0.89] and 0.75 [95% CI, 0.60-0.95], respectively). With each additional metabolic criterion from 0 to 3, adjusted 28-day mortality was reduced by 18%, 22%, and 40%, respectively. In subgroup analyses stratifying by ARDS etiology, mortality was lower for metabolic syndrome vs. control in ARDS caused by sepsis or pneumonia (at 28 d, aOR 0.64 [95% CI, 0.48-0.84] and 90 d, aOR 0.69 [95% CI, 0.53-0.89]), but not in ARDS from noninfectious causes (at 28 d, aOR 1.18 [95% CI, 0.70-1.99] and 90 d, aOR 1.26 [95% CI, 0.77-2.06]). Interaction p = 0.04 and p = 0.02 for 28- and 90-day comparisons, respectively.

CONCLUSIONS

Metabolic syndrome in ARDS was associated with a lower risk of mortality in non-COVID-19 ARDS. The relationship between metabolic inflammation and ARDS may provide a novel biological pathway to be explored in precision medicine-based trials.

Association of energy delivery with short-term survival in mechanically ventilated critically ill adult patients: a secondary analysis of the NEED trial

BACKGROUND AND AIMS

The optimal energy delivery for mechanically ventilated patients is controversial, particularly during the first week of ICU admission. This study aimed to investigate the association between different caloric adequacy and 28-day mortality in a cohort of critically ill adults on mechanical ventilation.

METHODS

This is a secondary analysis of a multicenter, cluster-randomized controlled trial. Eligible patients were divided into four quartiles (Q1-Q4) according to caloric adequacy calculated by the actual average daily energy delivery during the first seven days of ICU stay divided by energy requirement as a percentage. Cox proportional hazards models were used to examine the impact of different quartiles of caloric adequacy on 28-day mortality in the whole cohort and subgroups with different nutritional risk status at enrollment.

RESULTS

A total of 1587 patients were included in this study, with an overall 28-day mortality of 15.8%. The average caloric adequacy was 26.3 ± 11.9% (Q1), 52.5 ± 5.5% (Q2), 71.7 ± 6.4% (Q3), 107.0 ± 22.2% (Q4), respectively (p < 0.001 among quartiles). Compared with Q1, Q3 was associated with lower mortality in the unadjusted model (hazard ratio [HR] = 0.536; 95% confidence interval [CI], 0.375-0.767; P = 0.001) and adjusted model (adjusted HR = 0.508; 95% CI, 0.339-0.761; P = 0.001). This association remained valid in the subgroup of high nutritional risk patients (unadjusted HR = 0.387; 95% CI, 0.238-0.627; P < 0.001 and adjusted HR = 0.369; 95% CI, 0.216-0.630; P < 0.001, respectively), but not in those with low risk.

CONCLUSIONS

Energy delivery near the 70% energy requirements in the first week of ICU stay was associated with reduced 28-day mortality among mechanically ventilated critically ill patients, especially in patients with high nutrition risk at admission.

Association of tryptophan pathway metabolites with mortality and effectiveness of nutritional support among patients at nutritional risk: secondary analysis of a randomized clinical trial

Tryptophan is an essential amino acid and is the precursor of many important metabolites and neurotransmitters. In malnutrition, the availability of tryptophan is reduced, potentially putting patients at increased risks. Herein, we investigated the prognostic implications of the tryptophan metabolism in a secondary analysis of the Effect of Early Nutritional Support on Frailty, Functional Outcomes, and Recovery of Malnourished Medical Inpatients Trial (EFFORT), a randomized, controlled trial comparing individualized nutritional support to usual care in patients at risk for malnutrition. Among 238 patients with available measurements, low plasma levels of metabolites were independently associated with 30-day mortality with adjusted hazard ratios (HR) of 1.77 [95% CI 1.05-2.99, p 0.034] for tryptophan, 3.49 [95% CI 1.81-6.74, p < 0.001] for kynurenine and 2.51 [95% CI 1.37-4.63, p 0.003] for serotonin. Nutritional support had more beneficial effects on mortality in patients with high tryptophan compared to patients with low tryptophan levels (adjusted HR 0.61 [95% CI 0.29-1.29] vs. HR 1.72 [95% CI 0.79-3.70], p for interaction 0.047). These results suggest that sufficient circulating levels of tryptophan might be a metabolic prerequisite for the beneficial effect of nutritional interventions in this highly vulnerable patient population.

PROLONGED MECHANICAL VENTILATION IN ACUTE RESPIRATORY DISTRESS SYNDROME

ABSTRACT

Purpose: Trajectory of acute respiratory distress syndrome (ARDS) spans from rapidly improving cases to cases receiving prolonged mechanical ventilation (PMV). We attempted to estimate temporal trends of prevalence and mortality of PMV and to identify risk factors associated with mortality of patients with ARDS receiving PMV. Methods: We performed a secondary analysis of individual patient data from six randomized controlled clinical trials conducted by the ARDS Network. Prolonged mechanical ventilation was defined as the need for mechanical ventilation for >21 consecutive days. Results: Of 4,216 patients with ARDS, 646 (15.3%) received PMV. Prevalence of PMV gradually declined from 18.4% in the ARDS Network: Low-Tidal-Volume Trial (published in 2000) trial to 10.9% in the SAILS (2014) trial ( R2 = 0.728, P = 0.031). Ninety-day mortality of patients receiving PMV did not change over time ( R2 = 0.271, P = 0.290) and remained as high as 36.8%. Ιn the three most recent trials, risk factors associated with mortality among the 250 patients with ARDS receiving PMV included age, malignancy, pneumonia as the cause of ARDS, coagulation dysfunction, and hepatic dysfunction during the first 21 days after trial enrollment. Conclusion: Although prevalence of PMV among patients enrolled in ARDS Network trials gradually declined, mortality did not change. Risk factors associated with mortality were mostly nonmodifiable.

The Obesity Paradox in the Pediatric Trauma Patient

BACKGROUND

Obesity is a chronic disease that adversely impacts patient outcomes and increasingly affecting the pediatric population. According to the CDC, in 2020 the prevalence of obesity among children and adolescents was estimated to be as high as 19.7%. The obesity paradox is the increased survival for overweight and obese adult trauma patients when compared to patients with healthy weights. The aim of this study was to analyze the impact of BMI and outcomes in the pediatric trauma population.

METHODS

Trauma patients in the 2-18 years age group and reported to the 2017-2019 National Trauma Data Bank were identified. CDC growth charts and z-scores were calculated to categorize patients into four subgroups: underweight (<5th percentile), healthy weight (5th-85th percentile), overweight (85th-95th percentile), and obesity (>95th percentile). Primary outcome studied was the mortality rate. Secondary outcomes included injury severity score (ISS), hospital length of stay (LOS), ICU LOS, and number of days on a ventilator. Continuous and categorical data were analyzed using ANOVA and Chi-squared test, respectively, using the healthy BMI category as reference group. P < 0.05 was considered significant.

RESULTS

A total of 161,458 patients [Underweight: 9148 (6%), Healthy weight: 88,009 (55%), Overweight: 26,740 (17%), and Obese: 37,561 (23%)] were included. The mean age was 11 years (SD:5.1). Total mortality for the patient set was 1825 (1.13%). The lowest mortality rate was in the obese group. The ISS was lowest in the obese group, while ICU LOS and days on ventilator were no different than control patients. Hospital LOS and transfer to rehabilitation rates were higher in the obese population.

CONCLUSION

Obesity appears to have a protective effect on mortality and significantly better secondary outcomes in the pediatric trauma population. Further study is necessary to evaluate the interplay between body weight and outcomes in pediatric trauma and disease states.

LEVEL OF EVIDENCE

III.

Impact of daily cyclic enteral nutrition versus standard continuous enteral nutrition in critically ill patients: a study protocol for a randomised controlled trial in three intensive care units in France (DC-SCENIC)

INTRODUCTION

Current guidelines on clinical nutrition of ventilated patients in the intensive care unit (ICU) recommend initiating continuous enteral nutrition within 48 hours of ICU admission when feasible. However, discontinuous feeding regimens, alternating feeding and fasting intervals, may have an impact on clinical and patient centred outcomes. The ongoing "Impact of daily cyclic enteral nutrition versus standard continuous enteral nutrition in critically ill patients" (DC-SCENIC) trial aims to compare standard continuous enteral feeding with daily cyclic enteral feeding over 10 hours to evaluate if implementing a fasting-mimicking diet can decrease organ failure in ventilated patients during the acute phase of ICU management.

METHODS AND ANALYSIS

DC-SCENIC is a randomised, controlled, multicentre, open-label trial comparing two parallel groups of patients 18 years of age or older receiving invasive mechanical ventilation and having an indication for enteral nutrition through a gastric tube. Enteral feeding is continuous in the control group and administered over 10 hours daily in the intervention group. Both groups receive isocaloric nutrition with 4 g of protein per 100 mL, and have the same 20 kcal/kg/day caloric target. The primary endpoint is the change in the Sequential Organ Failure Assessment score at 7 days compared with the day of inclusion in the study. Secondary outcomes include daily caloric and protein delivery, digestive, respiratory and metabolic tolerance as well as 28-day mortality, duration of mechanical ventilation and ventilator-free days. Outcomes will be analysed on an intention-to-treat basis. Recruitment started in June 2023 in 3 French ICU's and a sample size of 318 patients is expected by February 2026.

ETHICS AND DISSEMINATION

This study received approval from the national ethics review board on 8 November 2022 (Comité de Protection des Personnes Sud-Est VI, registration number 2022-A00827-36). Patients are included after informed consent. Results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05627167.

Efficacy of permissive underfeeding for critically ill patients: an updated systematic review and trial sequential meta-analysis

BACKGROUND

Our previous study in 2011 concluded that permissive underfeeding may improve outcomes in patients receiving parenteral nutrition therapy. This conclusion was tentative, given the small sample size. We conducted the present systematic review and trial sequential meta-analysis to update the status of permissive underfeeding in patients who were admitted to the intensive care unit (ICU).

METHODS

Seven databases were searched: PubMed, Embase, Web of Science, China National Knowledge Infrastructure, Wanfang, Chinese Biomedical Literature Database, and Cochrane Library. Randomized controlled trials (RCTs) were included. The Revised Cochrane risk-of-bias tool (ROB 2) was used to assess the risk of bias in the enrolled trials. RevMan software was used for data synthesis. Trial sequential analyses (TSA) of overall and ICU mortalities were performed.

RESULTS

Twenty-three RCTs involving 11,444 critically ill patients were included. There were no significant differences in overall mortality, hospital mortality, length of hospital stays, and incidence of overall infection. Compared with the control group, permissive underfeeding significantly reduced ICU mortality (risk ratio [RR] = 0.90; 95% confidence interval [CI], [0.81, 0.99]; P = 0.02; I2 = 0%), and the incidence of gastrointestinal adverse events decreased (RR = 0.79; 95% CI, [0.69, 0.90]; P = 0.0003; I2 = 56%). Furthermore, mechanical ventilation duration was reduced (mean difference (MD) = - 1.85 days; 95% CI, [- 3.44, - 0.27]; P = 0.02; I2 = 0%).

CONCLUSIONS

Permissive underfeeding may reduce ICU mortality in critically ill patients and help to shorten mechanical ventilation duration, but the overall mortality is not improved. Owing to the sample size and patient heterogeneity, the conclusions still need to be verified by well-designed, large-scale RCTs. Trial Registration The protocol for our meta-analysis and systematic review was registered and recorded in PROSPERO (registration no. CRD42023451308). Registered 14 August 2023.

Enhanced exclusive enteral nutrition delivery during the first 7 days is associated with decreased 28-day mortality in critically ill patients with normal lactate level: a post hoc analysis of a multicenter randomized trial

BACKGROUND AND AIMS

Exclusive enteral nutrition (EN) is often observed during the first week of ICU admission because of the extra costs and safety considerations for early parenteral nutrition. This study aimed to assess the association between nutrition intake and 28-day mortality in critically ill patients receiving exclusive EN.

METHODS

This is a post hoc analysis of a cluster-randomized clinical trial that assesses the effect of implementing a feeding protocol on mortality in critically ill patients. Patients who stayed in the ICUs for at least 7 days and received exclusive EN were included in this analysis. Multivariable Cox hazard regression models and restricted cubic spline models were used to assess the relationship between the different doses of EN delivery and 28-day mortality. Subgroups with varying lactate levels at enrollment were additionally analyzed to address the potential confounding effect brought in by the presence of shock-related hypoperfusion.

RESULTS

Overall, 1322 patients were included in the analysis. The median (interquartile range) daily energy and protein delivery during the first week of enrollment were 14.6 (10.3-19.6) kcal/kg and 0.6 (0.4-0.8) g/kg, respectively. An increase of 5 kcal/kg energy delivery was associated with a significant reduction (approximately 14%) in 28-day mortality (adjusted hazard ratio [HR] = 0.865, 95% confidence interval [CI]: 0.768-0.974, P = 0.016). For protein intake, a 0.2 g/kg increase was associated with a similar mortality reduction with an adjusted HR of 0.868 (95% CI 0.770-0.979). However, the benefits associated with enhanced nutrition delivery could be observed in patients with lactate concentration ≤ 2 mmol/L (adjusted HR = 0.804 (95% CI 0.674-0.960) for energy delivery and adjusted HR = 0.804 (95% CI 0.672-0.962) for protein delivery, respectively), but not in those > 2 mmol/L.

CONCLUSIONS

During the first week of critical illness, enhanced nutrition delivery is associated with reduced mortality in critically ill patients receiving exclusive EN, only for those with lactate concentration ≤ 2 mmol/L.

TRIAL REGISTRATION

ISRCTN12233792, registered on November 24, 2017.

A combination of mild-moderate hypoxemia and low compliance is highly prevalent in persistent ARDS: a retrospective study

BACKGROUND

The Acute Respiratory Distress Syndrome (ARDS) is characterized by lung inflammation and edema, impairing both oxygenation and lung compliance. Recent studies reported a dissociation between oxygenation and compliance (severe hypoxemia with preserved compliance) in early ARDS and COVID-19-related-ARDS (CARDS). During the pandemic, in patients requiring prolonged mechanical ventilation, we observed the opposite combination (mild-moderate hypoxemia but significantly impaired compliance). The purpose of our study was to investigate the prevalence of this combination of mild-moderate hypoxemia and impaired compliance in persistent ARDS and CARDS.

METHODS

For this retrospective study, we used individual patient-level data from two independent cohorts of ARDS patients. The ARDSNet cohort included patients from four ARDS Network randomized controlled trials. The CARDS cohort included patients with ARDS due to COVID-19 hospitalized in two intensive care units in Greece. We used a threshold of 150 for PaO2/FiO2 and 30 ml/cmH2O for compliance, estimated the prevalence of each of the four combinations of oxygenation and compliance at baseline, and examined the change in its prevalence from baseline to day 21 in the ARDSNet and CARDS cohorts.

RESULTS

The ARDSNet cohort included 2909 patients and the CARDS cohort included 349 patients. The prevalence of the combination of mild-moderate hypoxemia and low compliance increased from baseline to day 21 both in the ARDSNet cohort (from 22.2 to 42.7%) and in the CARDS cohort (from 3.1 to 33.3%). Among surviving patients with low compliance, oxygenation improved over time. The 60-day mortality rate was higher for patients who had mild-moderate hypoxemia and low compliance on day 21 (28% and 56% in ARDSNet and CARDS), compared to those who had mild-moderate hypoxemia and high compliance (20% and 50%, respectively).

CONCLUSIONS

Among patients with ARDS who require prolonged controlled mechanical ventilation, regardless of ARDS etiology, a dissociation between oxygenation and compliance characterized by mild-moderate hypoxemia but low compliance becomes increasingly prevalent. The findings of this study highlight the importance of monitoring mechanics in patients with persistent ARDS.

Enteral feeding strategies in patients with acute gastrointestinal injury: From limited to progressive to open feeding

Acute gastrointestinal injury (AGI) is very common in critically ill patients, and its severity is positively correlated with mortality. Critically ill patients with digestive and absorption dysfunction caused by AGI face higher nutritional risks, making nutritional support particularly important. Early enteral nutrition (EN) support is extremely important because it can promote the recovery of intestinal function, protect the intestinal mucosal barrier, reduce microbiota translocation, reduce postoperative complications, shorten hospital stay, and improve clinical prognosis. In recent years, many nutritional guidelines have been proposed for critically ill patients; however, there are few recommendations for the implementation of EN in patients with AGI, and their quality of evidence is low. The use of EN feeding strategies in critically ill patients with AGI remains controversial. The aim of this review was to elaborate on how EN feeding strategies should transition from limited to progressive to open feeding and explain the time window for this transition.

Nutrition practices in critically ill adults receiving noninvasive ventilation: A quantitative survey of Australian and New Zealand intensive care clinicians

BACKGROUND

Noninvasive ventilation (NIV) is frequently used in the intensive care unit (ICU), yet there is a paucity of evidence to guide nutrition management during this therapy. Understanding clinicians' views on nutrition practices during NIV will inform research to address this knowledge gap.

OBJECTIVE

The objective of this study was to describe Australian and New Zealand clinicians' views and perceptions of nutrition management during NIV in critically ill adults.

METHODS

A cross-sectional quantitative online survey of Australian and New Zealand medical and nursing staff with ≥12 months ICU experience was disseminated through professional organisations via purposive snowball sampling from 29 August to 9 October 2022. Data collection included demographics, current practices, and views and perceptions of nutrition during NIV. Surveys <50% complete were excluded. Data are represented in number (%).

RESULTS

A total of 152 surveys were analysed; 71 (47%) nursing, 69 (45%) medical, and 12 (8%) not specified. There was limited consensus on nutrition management during NIV; however, most clinicians (n = 108, 79%) reported that nutrition during NIV was 'important or very important'. Oral intake was perceived to be the most common route (n = 83, 55%), and 29 (21%) respondents viewed this as the safest. Most respondents (n = 106, 78%) reported that ≤50% of energy targets were met, with gastric enteral nutrition considered most likely to meet targets (n = 55, 40%). Reported nutrition barriers were aspiration risk (n = 87, 64%), fasting for intubation (n = 84, 62%), and nutrition perceived as a lower priority (n = 73, 54%). Reported facilitators were evidence-based guidelines (n = 77, 57%) and an NIV interface compatible with enteral nutrition tube (n = 77, 57%).

CONCLUSION

ICU medical and nursing staff reported nutrition during NIV to be important; however, there was a lack of consensus on the route of feeding considered to be the safest and most likely to achieve nutrition targets. Interventions to minimise aspiration and fasting, including an interface with nasoenteric tube compatibility, should be explored.

Associations between In-Hospital Mortality and Prescribed Parenteral Energy and Amino Acid Doses in Critically Ill Patients: A Retrospective Cohort Study Using a Medical Claims Database

Some critically ill patients completely rely on parenteral nutrition (PN), which often cannot provide sufficient energy/amino acids. We investigated the relationship between PN doses of energy/amino acids and clinical outcomes in a retrospective cohort study using a medical claims database (≥10.5 years, from Japan, and involving 20,773 adult intensive care unit (ICU) patients on mechanical ventilation and exclusively receiving PN). Study patients: >70 years old, 63.0%; male, 63.3%; and BMI < 22.5, 56.3%. Initiation of PN: third day of ICU admission. PN duration: 12 days. In-hospital mortality: 42.5%. Patients were divided into nine subgroups based on combinations of the mean daily doses received during ICU days 4-7: (1) energy (very low <10 kcal/kg/day; low ≥10, <20; and moderate ≥20); (2) amino acids (very low <0.3 g/kg/day; low ≥0.3, <0.6; and moderate ≥0.6). For each subgroup, adjusted odds ratios (AORs) of in-hospital mortality with 95% confidence intervals (CIs) were calculated by regression analysis. The highest odds of mortality among the nine subgroups was in the moderate calorie/very low amino acid (AOR = 2.25, 95% CI 1.76-2.87) and moderate calorie/low amino acid (AOR = 1.68, 95% CI 1.36-2.08) subgroups, meaning a significant increase in the odds of mortality by between 68% and 125% when an amino acid dose of <0.6 g/kg/day was prescribed during ICU days 4-7, even when ≥20 kcal/kg/day of calories was prescribed. In conclusion, PN-dependent critically ill patients may have better outcomes including in-hospital mortality when ≥0.6 g/kg/day of amino acids is prescribed.

Improving enteral nutrition tolerance and protein intake maybe beneficial to intensive care unit patients

Enteral nutrition (EN) is important for critically ill patients. This study investigated the current situation of EN treatment in SHANGHAI intensive care units (ICUs). We hypothesized that improving EN practice in SHANGHAI may benefit the prognosis of ICU patients. Clinical information on EN use was collected using clinic information forms in 2019. The collected data included the patient's general clinical information, EN prescription status, EN tolerance status, and clinical outcomes. The observation time points were days 1, 3, and 7 after starting EN. A total of 491 patients were included. The proportion of EN intolerance (defined as < 20 kcal/kg/day) decreased, with rates of intolerance of 100%, 82.07%, 70.61%, and 52.23% at 1, 3, 7, and 14 days, respectively. Age, mNutric score, and protein intake < 0.5 g/kg/day on day 7 were risk factors for 28-day mortality.The EN tolerance on day 7 and protein intake > 0.5 g/kg/day on day 3 or day 7 might affect the 28-day mortality. Risk factors with EN tolerance on day 7 by logistic regression showed that the AGI grade on day 1 was a major factor against EN tolerance. The proportion of EN tolerance in SHANGHAI ICU patients was low. Achieving tolerance on day 7 after the start of EN is a protective factor for 28-day survival. Improving EN tolerance and protein intake maybe beneficial for ICU patients.

Racial and ethnic minority participants in clinical trials of acute respiratory distress syndrome

PURPOSE

There is growing interest in improving the inclusiveness of racial and ethnic minority participants in trials of acute respiratory distress syndrome (ARDS). With our study we aimed to examine temporal trends of representation and mortality of racial and ethnic minority participants in randomized controlled trials of ARDS.

METHODS

We performed a secondary analysis of eight ARDS Network and PETAL Network therapeutic clinical trials, published between 2000 and 2019. We classified race/ethnicity into "White", "Black", "Hispanic", or "Other" (including Asian, American Indian or Alaskan Native, Native Hawaiian, or other Pacific Islander participants).

RESULTS

Of 5375 participants with ARDS, 1634 (30.4%) were Black, Hispanic, or Other race participants. Representation of racial and ethnic minority participants in trials did not change significantly over time (p = 0.257). However, among participants with moderate to severe ARDS (i.e., partial pressure of arterial oxygen to fraction of inspired oxygen ratio < 150), the difference in mortality between racial and ethnic minority participants and White participants decreased over time. In the five most recent trials, including 2923 participants with ARDS, there were no statistically significant differences in mortality between racial/ethnic groups, even after adjusting for potential confounders. In these five most recent trials, mortality was 31% for White, 31.9% for Black, 30.3% for Hispanic, and 37.1% for Other race participants (p = 0.633).

CONCLUSION

Representation of racial and ethnic minority participants in ARDS trials from North America, published between 2000 and 2019, did not change over time. Black and Hispanic participants with ARDS may have similar mortality as White participants within trials.

Sigh Ventilation in Patients With Trauma: The SiVent Randomized Clinical Trial

Importance

Among patients receiving mechanical ventilation, tidal volumes with each breath are often constant or similar. This may lead to ventilator-induced lung injury by altering or depleting surfactant. The role of sigh breaths in reducing ventilator-induced lung injury among trauma patients at risk of poor outcomes is unknown.

Objective

To determine whether adding sigh breaths improves clinical outcomes.

Design, Setting, and Participants

A pragmatic, randomized trial of sigh breaths plus usual care conducted from 2016 to 2022 with 28-day follow-up in 15 academic trauma centers in the US. Inclusion criteria were age older than 18 years, mechanical ventilation because of trauma for less than 24 hours, 1 or more of 5 risk factors for developing acute respiratory distress syndrome, expected duration of ventilation longer than 24 hours, and predicted survival longer than 48 hours.

Interventions

Sigh volumes producing plateau pressures of 35 cm H2O (or 40 cm H2O for inpatients with body mass indexes >35) delivered once every 6 minutes. Usual care was defined as the patient's physician(s) treating the patient as they wished.

Main Outcomes and Measures

The primary outcome was ventilator-free days. Prespecified secondary outcomes included all-cause 28-day mortality.

Results

Of 5753 patients screened, 524 were enrolled (mean [SD] age, 43.9 [19.2] years; 394 [75.2%] were male). The median ventilator-free days was 18.4 (IQR, 7.0-25.2) in patients randomized to sighs and 16.1 (IQR, 1.1-24.4) in those receiving usual care alone (P = .08). The unadjusted mean difference in ventilator-free days between groups was 1.9 days (95% CI, 0.1 to 3.6) and the prespecified adjusted mean difference was 1.4 days (95% CI, -0.2 to 3.0). For the prespecified secondary outcome, patients randomized to sighs had 28-day mortality of 11.6% (30/259) vs 17.6% (46/261) in those receiving usual care (P = .05). No differences were observed in nonfatal adverse events comparing patients with sighs (80/259 [30.9%]) vs those without (80/261 [30.7%]).

Conclusions and Relevance

In a pragmatic, randomized trial among trauma patients receiving mechanical ventilation with risk factors for developing acute respiratory distress syndrome, the addition of sigh breaths did not significantly increase ventilator-free days. Prespecified secondary outcome data suggest that sighs are well-tolerated and may improve clinical outcomes.

Trial Registration

ClinicalTrials.gov Identifier: NCT02582957.

Small peptide formulas versus standard polymeric formulas in critically ill patients with acute gastrointestinal injury: a systematic review and meta-analysis

Small peptide formulas versus standard polymeric formulas for enteral nutrition in critically ill patients with acute gastrointestinal injury (AGI) have been a topic of debate. A systematic review and meta-analysis were conducted to compare their clinical and nutritional outcomes. Relevant studies from January 1980 to June 2022 were searched in PubMed, Cochrane, and Embase databases. Randomized controlled trials involving AGI grade I-IV patients were included, while children, non-AGI patients, and non-critically ill patients were excluded. Results indicated no significant difference in all-cause mortality. Patients receiving small peptide formulas showed higher daily protein intake, greater albumin growth, and higher prealbumin levels. They also had shorter lengths of stay in the intensive care unit and hospital. Conversely, patients receiving standard polymeric formulas had a higher daily calorie intake. In conclusion, the choice of formula may not affect mortality in critically ill patients with AGI. Small peptide formulas were more conducive to increase daily protein intake, decrease intensive care unit and hospital length of stay. Further large-scale randomized controlled trials evaluating the effects of these two nutritional formulas on clinical and nutritional outcomes in critically ill patients with AGI are needed to confirm these results.

Japanese Clinical Practice Guidelines for Rehabilitation in Critically Ill Patients 2023 (J-ReCIP 2023)

Providing standardized, high-quality rehabilitation for critically ill patients is a crucial issue. In 2017, the Japanese Society of Intensive Care Medicine (JSICM) promulgated the "Evidence-Based Expert Consensus for Early Rehabilitation in the Intensive Care Unit" to advocate for the early initiation of rehabilitations in Japanese intensive care settings. Building upon this seminal work, JSICM has recently conducted a rigorous systematic review utilizing the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. This endeavor resulted in the formulation of Clinical Practice Guidelines (CPGs), designed to elucidate best practices in early ICU rehabilitation. The primary objective of this guideline is to augment clinical understanding and thereby facilitate evidence-based decision-making, ultimately contributing to the enhancement of patient outcomes in critical care settings. No previous CPGs in the world has focused specifically on rehabilitation of critically ill patients, using the GRADE approach. Multidisciplinary collaboration is extremely important in rehabilitation. Thus, the CPGs were developed by 73 members of a Guideline Development Group consisting of a working group, a systematic review group, and an academic guideline promotion group, with the Committee for the Clinical Practice Guidelines of Early Mobilization and Rehabilitation in Intensive Care of the JSICM at its core. Many members contributed to the development of the guideline, including physicians and healthcare professionals with multiple and diverse specialties, as well as a person who had been patients in ICU. Based on discussions among the group members, eight important clinical areas of focus for this CPG were identified. Fourteen important clinical questions (CQs) were then developed for each area. The public was invited to comment twice, and the answers to the CQs were presented in the form of 10 GRADE recommendations and commentary on the four background questions. In addition, information for each CQ has been created as a visual clinical flow to ensure that the positioning of each CQ can be easily understood. We hope that the CPGs will be a useful tool in the rehabilitation of critically ill patients for multiple professions.

The intensity of organ support: Restrictive or aggressive therapy for critically ill patients

The intensity of organ support has received attention in recent years. To make better clinical decisions, we should understand the mechanisms and benefits, and disadvantages of the different intensities of organ support in critically ill patients. Therapeutic strategies such as supplemental oxygen therapy, mechanical ventilation, respiratory stimulant, vasoactive agents, transfusion, albumin infusion, fluid management, renal placement, and nutrition support, if they are implemented in accordance with an aggressive strategy, could result in side effects and/or complications, resulting in iatrogenic harm in critically ill patients. It is found that the intensity of organ support is not a determining factor in prognosis. A normal rather than supernormal physiological target is recommended for support therapy.

Postoperative acute respiratory distress syndrome in randomized controlled trials

BACKGROUND

Acute respiratory distress syndrome is a potentially fatal postoperative complication. We aimed to estimate temporal trends of the representation of patients with postoperative acute respiratory distress syndrome in clinical trials, determine their distinct clinical features, and identify predictors of mortality.

METHODS

This is a secondary analysis of 7 randomized controlled clinical trials conducted by the Acute Respiratory Distress Syndrome Network and the Clinical Trials Network for the Prevention and Early Treatment of Acute Lung Injury. Patients with acute respiratory distress syndrome were classified into a postoperative acute respiratory distress syndrome group (ie, patients who had undergone elective surgery in the immediate period before trial enrollment) and a non-postoperative acute respiratory distress syndrome group.

RESULTS

Out of 5,316 patients with acute respiratory distress syndrome, 256 (4.8%) had postoperative acute respiratory distress syndrome. Representation of postoperative acute respiratory distress syndrome in trials gradually declined from 2000 to 2011, but it remained stable afterward at 2.7%. Postoperative acute respiratory distress syndrome was associated with lower 90-day mortality (24.6% vs 30.9%, P = .032) than non-postoperative acute respiratory distress syndrome, even after adjusting for age, acute respiratory distress syndrome severity, usage of vasopressors at baseline, and the study publication year (hazard ratio 0.63, 95% confidence interval 0.49-0.82). Age (odds ratio 1.07, 95% confidence interval 1.04-1.09), immunosuppression (odds ratio 4.12, 95% confidence interval 1.43-11.86), and positive fluid balance (odds ratio 1.09, 95% confidence interval 1.04-1.14) were associated with 90-day mortality among patients with postoperative acute respiratory distress syndrome.

CONCLUSION

Representation of postoperative acute respiratory distress syndrome in trials of the Acute Respiratory Distress Syndrome Network and the Clinical Trials Network for the Prevention and Early Treatment of Acute Lung Injury gradually declined from 2000 to 2011 but remained stable afterward. Postoperative acute respiratory distress syndrome was associated with lower mortality than non-postoperative acute respiratory distress syndrome. These findings may put both temporal trends and the prognosis of postoperative acute respiratory distress syndrome in perspective. Also, positive fluid balance was associated with the mortality of patients with postoperative acute respiratory distress syndrome.

"The Big Three" of geriatrics: A review of perioperative cognitive impairment, frailty and malnutrition

Cognitive impairment, frailty, and malnutrition are three of the most impactful pathologies facing an aging population, having dramatic effects on morbidity and mortality across nearly all facets of medical care and intervention. By 2050, the World Health Organization estimates that the population of individuals over the age of sixty worldwide will nearly double, and the public health toll of these demographic changes cannot be understated. With these changing demographics comes a need for a sharpened focus on the care and management of this vulnerable population. The average patient presenting for surgery is getting older, and this necessitates that clinicians understand the implications of these pathologies for both their immediate medical care needs and for appropriate procedural selection and prognostication of surgical outcomes. We believe it is incumbent on clinicians to consider the frailty, nutritional status, and cognitive function of each individual patient when offering a surgical intervention, as well as consider interventions that may delay the progression of these pathologies. Unfortunately, despite excellent evidence supporting things like routine pre-operative frailty screening and nutritional optimization, many interventions that would specifically benefit this population still have not been integrated into routine practice. In this review, we will synthesize the existing literature on these topics to provide a pragmatic approach and understanding for anesthesiologists and intensivists faced with this complex population.

Body composition and muscle strength at the end of ICU stay are associated with 1-year mortality, a prospective multicenter observational study

BACKGROUND & AIMS

After a prolonged intensive care unit (ICU) stay patients experience increased mortality and morbidity. The primary aim of this study was to assess the prognostic value of nutritional status, body mass composition and muscle strength, as assessed by body mass index (BMI), bioelectrical impedance analysis (BIA), handgrip (HG) test, and that of the biological features to predict one-year survival at the end of a prolonged ICU stay.

METHODS

This was a multicenter prospective observational study. Survivor patients older than 18 years with ICU length of stay >72 h were eligible for inclusion. BIA and HG were performed at the end of the ICU stay. Malnutrition was defined by BMI and fat-free mass index (FFMI). The primary endpoint was one-year mortality. Multivariable logistic regression was performed to determine parameters associated with mortality.

RESULTS

572 patients were included with a median age of 63 years [53.5; 71.1], BMI of 26.6 kg/m2 [22.8; 31.3], SAPS II score of 43 [31; 58], and ICU length of stay of 9 days [6; 15]. Malnutrition was observed in 142 (24.9%) patients. During the 1-year follow-up after discharge, 96 (18.5%) patients died. After adjustment, a low HG test score (aOR = 1.44 [1.11; 1.89], p = 0.01) was associated with 1-year mortality. Patients with low HG score, malnutrition, and Albuminemia <30 g/L had a one-year death rate of 41.4%. Conversely, patients with none of these parameters had a 1-year death rate of 4.1%.

CONCLUSION

BIA to assess FFMI, HG and albuminemia at the end of ICU stay could be used to predict 1-year mortality. Their ability to identify patients eligible for a structured recovery program could be studied.

Nutrition dose in the early acute phase of critical illness: Finding the sweet spot and heeding the lessons from the NUTRIREA trials

The landmark NUTRIREA-2 and NUTRIREA-3 trials compared the route and dose of nutrition, respectively, in critically ill patients with circulatory shock. The results of both trials support a "less-is-more" paradigm shift in the early acute phase of critical illness. In this review, the authors outline and appraise the results of the NUTRIREA-2 and NUTRIREA-3 trials, introduce the concept of identifying the "sweet spot" for nutrition dose based on severity of illness/nutrition risk and nutrition dose, and identify the unintended consequences of delivering full-dose nutrition in sicker critically ill patients during the early acute phase of critical illness.

Nutrition care processes from intensive care unit admission to inpatient rehabilitation: A retrospective observational study

OBJECTIVES

Extended duration of nutrition interventions in critical illness is a plausible mechanism of benefit and of interest to inform future research. The aim of this study was to describe nutrition processes of care from intensive care unit (ICU) admission to discharge from inpatient rehabilitation.

METHODS

This was a single-center retrospective study conducted at a health care network in Melbourne, Australia. Adult patients in the ICU >48 h and discharged to inpatient rehabilitation within 28 d were included. Dietitian assessment data and nutrition impacting symptoms were collected until day 28. Data are presented as n (%), mean ± SD or median (interquartile range).

RESULTS

Fifty patients were included. Of the 50 patients, 28 were men (56%). Patients were 65 ± 19 y of age with an Acute Physiology And Chronic Health Evaluation II score 15.5 ± 5.2. ICU length of stay (LOS) was 3 d (3-6), acute ward LOS was 10 d (7-14), and rehabilitation LOS was 17 d (8-37). Patients assessed by a dietitian and days to assessment in ICU, acute ward, and rehabilitation were 43 (86%) and 1 (0-1); 42 (84%) and 1 (1-3), and 32 (64%) and 2 (1-4) d, respectively. Oral nutrition was the most common mode: 40 (80%) in the ICU and 48 (96%) on the acute ward and rehabilitation. There was at least one nutrition impacting symptom reported in 44 patients (88%).

CONCLUSIONS

Rehabilitation LOS was longer than in the ICU or acute wards, yet patients in rehabilitation were assessed the least by a dietitian and time to assessment was longest. Symptoms that impact nutrition intake were common; nutrition interventions beyond the acute care setting in critical illness need investigation.

Sample size estimation in clinical trials using ventilator-free days as the primary outcome: a systematic review

BACKGROUND

Ventilator-free days (VFDs) are a composite endpoint increasingly used as the primary outcome in critical care trials. However, because of the skewed distribution and competitive risk between components, sample size estimation remains challenging. This systematic review was conducted to systematically assess whether the sample size was congruent, as calculated to evaluate VFDs in trials, with VFDs' distribution and the impact of alternative methods on sample size estimation.

METHODS

A systematic literature search was conducted within the PubMed and Embase databases for randomized clinical trials in adults with VFDs as the primary outcome until December 2021. We focused on peer-reviewed journals with 2021 impact factors greater than five. After reviewing definitions of VFDs, we extracted the sample size and methods used for its estimation. The data were collected by two independent investigators and recorded in a standardized, pilot-tested forms tool. Sample sizes were calculated using alternative statistical approaches, and risks of bias were assessed with the Cochrane risk-of-bias tool.

RESULTS

Of the 26 clinical trials included, 19 (73%) raised "some concerns" when assessing risks of bias. Twenty-four (92%) trials were two-arm superiority trials, and 23 (89%) were conducted at multiple sites. Almost all the trials (96%) were unable to consider the unique distribution of VFDs and death as a competitive risk. Moreover, significant heterogeneity was found in the definitions of VFDs, especially regarding varying start time and type of respiratory support. Methods for sample size estimation were also heterogeneous, and simple models, such as the Mann-Whitney-Wilcoxon rank-sum test, were used in 14 (54%) trials. Finally, the sample sizes calculated varied by a factor of 1.6 to 17.4.

CONCLUSIONS

A standardized definition and methodology for VFDs, including the use of a core outcome set, seems to be required. Indeed, this could facilitate the interpretation of findings in clinical trials, as well as their construction, especially the sample size estimation which is a trade-off between cost, ethics, and statistical power. Systematic review registration PROSPERO ID: CRD42021282304. Registered 15 December 2021 ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021282304 ).

Low versus standard calorie and protein feeding in ventilated adults with shock: a randomised, controlled, multicentre, open-label, parallel-group trial (NUTRIREA-3)

BACKGROUND

The optimal calorie and protein intakes at the acute phase of severe critical illness remain unknown. We hypothesised that early calorie and protein restriction improved outcomes in these patients, compared with standard calorie and protein targets.

METHODS

The pragmatic, randomised, controlled, multicentre, open-label, parallel-group NUTRIREA-3 trial was performed in 61 French intensive care units (ICUs). Adults (≥18 years) receiving invasive mechanical ventilation and vasopressor support for shock were randomly assigned to early nutrition (started within 24 h after intubation) with either low or standard calorie and protein targets (6 kcal/kg per day and 0·2-0·4 g/kg per day protein vs 25 kcal/kg per day and 1·0-1·3 g/kg per day protein) during the first 7 ICU days. The two primary endpoints were time to readiness for ICU discharge and day 90 all-cause mortality. Key secondary outcomes included secondary infections, gastrointestinal events, and liver dysfunction. The trial is registered on ClinicalTrials.gov, NCT03573739, and is completed.

FINDINGS

Of 3044 patients randomly assigned between July 5, 2018, and 8 Dec 8, 2020, eight withdrew consent to participation. By day 90, 628 (41·3%) of 1521 patients in the low group and 648 (42·8%) of 1515 patients in the standard group had died (absolute difference -1·5%, 95% CI -5·0 to 2·0; p=0·41). Median time to readiness for ICU discharge was 8·0 days (IQR 5·0-14·0) in the low group and 9·0 days (5·0-17·0) in the standard group (hazard ratio [HR] 1·12, 95% CI 1·02 to 1·22; p=0·015). Proportions of patients with secondary infections did not differ between the groups (HR 0·85, 0·71 to 1·01; p=0·06). The low group had lower proportions of patients with vomiting (HR 0·77, 0·67 to 0·89; p<0·001), diarrhoea (0·83, 0·73 to 0·94; p=0·004), bowel ischaemia (0·50, 0·26 to 0·95; p=0·030), and liver dysfunction (0·92, 0·86-0·99; p=0·032).

INTERPRETATION

Compared with standard calorie and protein targets, early calorie and protein restriction did not decrease mortality but was associated with faster recovery and fewer complications.

FUNDING

French Ministry of Health.

Association of Interventions With Outcomes in Children At-Risk for Pediatric Acute Respiratory Distress Syndrome: A Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology Study

OBJECTIVES

Describe the frequency with which transfusion and medications that modulate lung injury are administered to children meeting at-risk for pediatric acute respiratory distress syndrome (ARF-PARDS) criteria and evaluate for associations of transfusion, fluid balance, nutrition, and medications with unfavorable clinical outcomes.

DESIGN

Secondary analysis of the Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology study, a prospective point prevalence study. All enrolled ARF-PARDS patients were included unless they developed subsequent pediatric acute respiratory distress syndrome (PARDS) within 24 hours of PICU admission or PICU length of stay was less than 24 hours. Univariate and multivariable analyses were used to identify associations between therapies given during the first 2 calendar days after ARF-PARDS diagnosis and subsequent PARDS diagnosis (primary outcome), 28-day PICU-free days (PFDs), and 28-day ventilator-free days (VFDs).

SETTING

Thirty-seven international PICUs.

PATIENTS

Two hundred sixty-seven children meeting Pediatric Acute Lung Injury Consensus Conference ARF-PARDS criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

During the first 2 days after meeting ARF-PARDS criteria, 55% of subjects received beta-agonists, 42% received corticosteroids, 28% received diuretics, and 9% were transfused. Subsequent PARDS (15%) was associated with platelet transfusion (n = 11; adjusted odds ratio: 4.75 [95% CI 1.03-21.92]) and diuretics (n = 74; 2.55 [1.19-5.46]) in multivariable analyses that adjusted for comorbidities, PARDS risk factor, initial oxygen saturation by pulse oximetry:Fio2 ratio, and initial type of ventilation. Beta-agonists were associated with lower adjusted odds of subsequent PARDS (0.43 [0.19-0.98]). Platelets and diuretics were also associated with fewer PFDs and fewer VFDs in the multivariable models, and TPN was associated with fewer PFDs. Corticosteroids, net fluid balance, and volume of enteral feeding were not associated with the primary or secondary outcomes.

CONCLUSIONS

There is an independent association between platelet transfusion, diuretic administration, and unfavorable outcomes in children at risk for PARDS, although this may be related to treatment bias and unmeasured confounders. Nevertheless, prospective evaluation of the role of these management strategies on outcomes in children with ARF-PARDS is needed.

How to avoid harm with feeding critically ill patients: a synthesis of viewpoints of a basic scientist, dietitian and intensivist

The optimal feeding strategy in critically ill patients is a matter of debate, with current guidelines recommending different strategies regarding energy and protein targets. Several recent trials have added to the debate and question our previous understanding of the provision of nutrition during critical illness. This narrative review aims to provide a summary of interpretation of recent evidence from the view of basic scientist, critical care dietitian and intensivist, resulting in joined suggestions for both clinical practice and future research. In the most recent randomised controlled trial (RCT), patients receiving 6 versus 25 kcal/kg/day by any route achieved readiness for ICU discharge earlier and had fewer GI complications. A second showed that high protein dosage may be harmful in patients with baseline acute kidney injury and more severe illness. Lastly, a prospective observational study using propensity score matched analysis suggested that early full feeding, especially enteral, compared to delayed feeding is associated with a higher 28-day mortality. Viewpoints from all three professionals point to the agreement that early full feeding is likely harmful, whereas important questions regarding the mechanisms of harm as well as on timing and optimal dose of nutrition for individual patients remain unanswered and warrant future studies. For now, we suggest giving low dose of energy and protein during the first few days in the ICU and apply individualised approach based on assumed metabolic state according to the trajectory of illness thereafter. At the same time, we encourage research to develop better tools to monitor metabolism and the nutritional needs for the individual patient accurately and continuously.

Metabolic Support in Acute Respiratory Distress Syndrome: A Narrative Review

Nutritional support for acute respiratory distress syndrome (ARDS) patients shares metabolic notions common to other critically ill conditions. Nevertheless, it generates specific concern regarding the primary limitation of oxygen supply and the complications of carbon dioxide elimination, as well as the significant metabolic alterations due to the body's response to illness. In the present narrative review, after briefly summarizing the pathophysiology of critical illness stress response and patients' metabolic requirements, we focus on describing the characteristics of metabolic and artificial nutrition in patients with acute respiratory failure. In patients with ARDS, several aspects of metabolism assume special importance. The physiological effects of substrate metabolism are described for this setting, particularly regarding energy consumption, diet-induced thermogenesis, and the price of their clearance, transformation, and storage. Moreover, we review the possible direct effects of macronutrients on lung tissue viability during ARDS. Finally, we summarize the noteworthy characteristics of metabolic control in critically ill patients with ARDS and offer a suggestion as to the ideal methods of metabolic support for this problem.