The Effect of Higher Protein Dosing in Critically Ill Patients: A Multicenter Registry-Based Randomized Trial: The EFFORT Trial

Looking to the future: Agendas, directions, and resources for nutrition research

The development and progression of nutrition as a scientific field is ever evolving and complex. Although the history of nutrition research began by exploring specific food components, it has evolved to encompass a more holistic view that considers the impact of dietary patterns over time, interactions with the environment, nutrition's role in disease processes, and public policy related to nutrition health. To guide the future direction of nutrition science, both federal and other professional organizations have established agendas and goals. The Strategic Plan for National Institutes of Health Nutrition Research outlines four goals and five cross-cutting research areas that are priorities to explore between 2020 and 2030. Similarly, the American Society for Parenteral and Enteral Nutrition and other governmental and professional organizations have identified priority areas in their research agendas. Rigorous research studies are needed to explore these areas of interest while also considering practical implementation strategies for translating research into practice. Nutrition clinicians are uniquely positioned to lend expertise in the areas of research design, implementation, advocacy and evidence-based practice; there are numerous resources to support practitioners in these endeavors.

A Comparison of High and Usual Protein Dosing in Critically Ill Patients With Obesity: A Post Hoc Analysis of an International, Pragmatic, Single-Blinded, Randomized Clinical Trial

OBJECTIVES

Across guidelines, protein dosing for critically ill patients with obesity varies considerably. The objective of this analysis was to evaluate whether this population would benefit from higher doses of protein.

DESIGN

A post hoc subgroup analysis of the effect of higher protein dosing in critically ill patients with high nutritional risk (EFFORT Protein): an international, multicenter, pragmatic, registry-based randomized trial.

SETTING

Eighty-five adult ICUs across 16 countries.

PATIENTS

Patients with obesity defined as a body mass index (BMI) greater than or equal to 30 kg/m 2 ( n = 425).

INTERVENTIONS

In the primary study, patients were randomized into a high-dose (≥ 2.2 g/kg/d) or usual-dose protein group (≤ 1.2 g/kg/d).

MEASUREMENTS AND MAIN RESULTS

Protein intake was monitored for up to 28 days, and outcomes (time to discharge alive [TTDA], 60-d mortality, days of mechanical ventilation [MV], hospital, and ICU length of stay [LOS]) were recorded until 60 days post-randomization. Of the 1301 patients in the primary study, 425 had a BMI greater than or equal to 30 kg/m 2 . After adjusting for sites and covariates, we observed a nonsignificant slower rate of TTDA with higher protein that ruled out a clinically important benefit (hazard ratio, 0.78; 95% CI, 0.58-1.05; p = 0.10). We found no evidence of difference in TTDA between protein groups when subgroups with different classes of obesity or patients with and without various nutritional and frailty risk variables were examined, even after the removal of patients with baseline acute kidney injury. Overall, 60-day mortality rates were 31.5% and 28.2% in the high protein and usual protein groups, respectively (risk difference, 3.3%; 95% CI, -5.4 to 12.1; p = 0.46). Duration of MV and LOS in hospital and ICU were not significantly different between groups.

CONCLUSIONS

In critically ill patients with obesity, higher protein doses did not improve clinical outcomes, including those with higher nutritional and frailty risk.

Association between urea trajectory and protein dose in critically ill adults: a secondary exploratory analysis of the effort protein trial (RE-EFFORT)

BACKGROUND

Delivering higher doses of protein to mechanically ventilated critically ill patients did not improve patient outcomes and may have caused harm. Longitudinal urea measurements could provide additional information about the treatment effect of higher protein doses. We hypothesised that higher urea values over time could explain the potential harmful treatment effects of higher doses of protein.

METHODS

We conducted a reanalysis of a randomised controlled trial of higher protein doses in critical illness (EFFORT Protein). We applied Bayesian joint models to estimate the strength of association of urea with 30-day survival and understand the treatment effect of higher protein doses.

RESULTS

Of the 1301 patients included in EFFORT Protein, 1277 were included in this analysis. There were 344 deaths at 30 days post-randomisation. By day 6, median urea was 2.1 mmol/L higher in the high protein group (95% CI 1.1-3.2), increasing to 3.0 mmol/L (95% CI 1.3-4.7) by day 12. A twofold rise in urea was associated with an increased risk of death at 30 days (hazard ratio 1.34, 95% credible interval 1.21-1.48), following adjustment of baseline characteristics including age, illness severity, renal replacement therapy, and presence of AKI. This association persisted over the duration of 30-day follow-up and in models adjusting for evolution of organ failure over time.

CONCLUSIONS

The increased risk of death in patients randomised to a higher protein dose in the EFFORT Protein trial was estimated to be mediated by increased urea cycle activity, of which serum urea is a biological signature. Serum urea should be taken into consideration when initiating and continuing protein delivery in critically ill patients.

CLINICALTRIALS

gov Identifier: NCT03160547 (2017-05-17).

Novel nutritional strategies to prevent muscle wasting

PURPOSE OF REVIEW

Muscle wasting in critical illness has proven to be refractory to physical rehabilitation, and to conventional nutritional strategies. This presents one of the central challenges to critical care medicine in the 21st century. Novel strategies are needed that facilitate nutritional interventions, identify patients that will benefit and have measurable, relevant benefits.

RECENT FINDINGS

Drug repurposing was demonstrated to be a powerful technique in the coronavirus disease 2019 pandemic, and may have similar applications to address the metabolic derangements of critical illness. Newer biological signatures may aid the application of these techniques and the association between changes in urea:creatinine ratio and the development of skeletal muscle wasting is increasing. A core outcome set for nutrition interventions in critical illness, supported by multiple international societies, was published earlier this year should be adopted by future nutrition trials aiming to attenuate muscle wasting.

SUMMARY

The evidence base for the lack of efficacy for conventional nutritional strategies in preventing muscle wasting in critically ill patients continues to grow. Novel strategies such as metabolic modulators, patient level biological signatures of nutritional response and standardized outcome for measurements of efficacy will be central to future research and clinical care of the critically ill patient.

Protein supplementation in critical illness: why, when and how?

PURPOSE OF REVIEW

In critically ill patients, optimal protein provision remains a challenge given the wide range in recommended protein delivery in international guidelines and the lack of robust, high quality evidence. As patients are confronted with poor functional outcomes after admission, often attributed to muscle wasting and persisting for multiple years, there is a pressing need for optimal nutritional strategies in the ICU, particularly including protein. This review will discuss the recent literature with regard to purpose, timing and mode of protein delivery.

RECENT FINDINGS

Recent studies on the effect of dose and timing of protein on clinical and functional outcomes are largely observational in nature and the protein delivery considered as "high" still often only nears the lower end of current recommendations. The majority of trials observed no effect of protein supplementation on mortality, muscle strength or function, though some report attenuation of muscle volume loss, especially when combined with muscle activation. There is no strong evidence that ICU patients should receive supplementation with any specific amino acids.

SUMMARY

Though adequate protein provision is likely important, it is difficult to come to a uniform conclusion regarding dosing and timing due to conflicting results in mostly observational studies as well as different cut-off values for high, moderate and low protein intake. This topic is currently subject to large clinical trials.

The effect of higher protein dosing in critically ill patients with high nutritional risk (EFFORT Protein): an international, multicentre, pragmatic, registry-based randomised trial

BACKGROUND

On the basis of low-quality evidence, international critical care nutrition guidelines recommend a wide range of protein doses. The effect of delivering high-dose protein during critical illness is unknown. We aimed to test the hypothesis that a higher dose of protein provided to critically ill patients would improve their clinical outcomes.

METHODS

This international, investigator-initiated, pragmatic, registry-based, single-blinded, randomised trial was undertaken in 85 intensive care units (ICUs) across 16 countries. We enrolled nutritionally high-risk adults (≥18 years) undergoing mechanical ventilation to compare prescribing high-dose protein (≥2·2 g/kg per day) with usual dose protein (≤1·2 g/kg per day) started within 96 h of ICU admission and continued for up to 28 days or death or transition to oral feeding. Participants were randomly allocated (1:1) to high-dose protein or usual dose protein, stratified by site. As site personnel were involved in both prescribing and delivering protein dose, it was not possible to blind clinicians, but patients were not made aware of the treatment assignment. The primary efficacy outcome was time-to-discharge-alive from hospital up to 60 days after ICU admission and the secondary outcome was 60-day morality. Patients were analysed in the group to which they were randomly assigned regardless of study compliance, although patients who dropped out of the study before receiving the study intervention were excluded. This study is registered with ClinicalTrials.gov, NCT03160547.

FINDINGS

Between Jan 17, 2018, and Dec 3, 2021, 1329 patients were randomised and 1301 (97·9%) were included in the analysis (645 in the high-dose protein group and 656 in usual dose group). By 60 days after randomisation, the cumulative incidence of alive hospital discharge was 46·1% (95 CI 42·0%-50·1%) in the high-dose compared with 50·2% (46·0%-54·3%) in the usual dose protein group (hazard ratio 0·91, 95% CI 0·77-1·07; p=0·27). The 60-day mortality rate was 34·6% (222 of 642) in the high dose protein group compared with 32·1% (208 of 648) in the usual dose protein group (relative risk 1·08, 95% CI 0·92-1·26). There appeared to be a subgroup effect with higher protein provision being particularly harmful in patients with acute kidney injury and higher organ failure scores at baseline.

INTERPRETATION

Delivery of higher doses of protein to mechanically ventilated critically ill patients did not improve the time-to-discharge-alive from hospital and might have worsened outcomes for patients with acute kidney injury and high organ failure scores.

FUNDING

None.

Medical nutrition therapy in patients receiving ECMO: Evidence-based guidance for clinical practice

Patients receiving extracorporeal membrane oxygenation (ECMO) inherit substantial disease-associated metabolic, endocrinologic, and immunologic modifications. Along with the technical components of ECMO, the aforementioned alterations may affect patients' needs and feasibility of adequate macronutrient and micronutrient supply and intake. Thus, patients receiving ECMO are at increased risk for iatrogenic malnutrition and require targeted individual medical nutrition therapy (MNT). However, specific recommendations for MNT in patients receiving ECMO are limited and, with some exceptions, based on an evidence base encompassing general patients who are critically ill. Consequently, clinician decision-making for MNT in patients receiving ECMO is unguided, which may further increase nutrition risk, culminating in iatrogenic malnutrition and ultimately affecting patient outcomes. The purpose of this article is to provide educational background and highlight specific points for MNT in adult patients receiving ECMO, which might serve as evidence-based guidance to develop institutional standard operating procedures and nutrition protocols for daily clinical practice.

Toward nutrition improving outcome of critically ill patients: How to interpret recent feeding RCTs?

Although numerous observational studies associated underfeeding with poor outcome, recent randomized controlled trials (RCTs) have shown that early full nutritional support does not benefit critically ill patients and may induce dose-dependent harm. Some researchers have suggested that the absence of benefit in RCTs may be attributed to overrepresentation of patients deemed at low nutritional risk, or to a too low amino acid versus non-protein energy dose in the nutritional formula. However, these hypotheses have not been confirmed by strong evidence. RCTs have not revealed any subgroup benefiting from early full nutritional support, nor benefit from increased amino acid doses or from indirect calorimetry-based energy dosing targeted at 100% of energy expenditure. Mechanistic studies attributed the absence of benefit of early feeding to anabolic resistance and futile catabolism of extra provided amino acids, and to feeding-induced suppression of recovery-enhancing pathways such as autophagy and ketogenesis, which opened perspectives for fasting-mimicking diets and ketone supplementation. Yet, the presence or absence of an anabolic response to feeding cannot be predicted or monitored and likely differs over time and among patients. In the absence of such monitor, the value of indirect calorimetry seems obscure, especially in the acute phase of illness. Until now, large feeding RCTs have focused on interventions that were initiated in the first week of critical illness. There are no large RCTs that investigated the impact of different feeding strategies initiated after the acute phase and continued after discharge from the intensive care unit in patients recovering from critical illness.

(Mal)nutrition in critical illness and beyond: a narrative review

Close liaison with ICU-trained dietitians and early initiation of nutrition is a fundamental principle of care of critically ill patients- this should be done while monitoring closely for refeeding syndrome. Enteral nutrition delivered by volumetric pumps should be used where possible, though parenteral nutrition should be started early in patients with high nutritional risk factors. Malnutrition and loss of muscle mass are common in patients who are admitted to ICUs and are prognostic for patient-centred outcomes including complications and mortality. Obesity is part of that story, and isocaloric and high-protein provision of nutrition is important in this group of patients who comprise a growing proportion of people treated. Assessing protein stores and appropriate dosing is, however, challenging in all groups of patients. It would be beneficial to develop strategies to reduce muscle wasting as well; various strategies including amino acid supplementation, ketogenic nutrition and exercise have been trialled, but the quality of data has been inadequate to address this phenomenon. Nutritional targets are rarely achieved in practice, and all ICUs should incorporate clear guidelines to help address this. These should include local nutritional and fasting guidelines and for the management of feed intolerance, early access to post-pyloric feeding and a multidisciplinary framework to support the importance of nutritional education.

Early versus delayed enteral nutrition in mechanically ventilated patients with circulatory shock: a nested cohort analysis of an international multicenter, pragmatic clinical trial

Introduction

Real-world evidence on the timing and efficacy of enteral nutrition (EN) practices in intensive care unit (ICU) patients with circulatory shock is limited. We hypothesized early EN (EEN), as compared to delayed EN (DEN), is associated with improved clinical outcomes in mechanically ventilated (MV) patients with circulatory shock.

Methods

We analyzed a dataset from an international, multicenter, pragmatic randomized clinical trial (RCT) evaluating protein dose in ICU patients. Data were collected from ICU admission, and EEN was defined as initiating < 48 h from ICU admission and DEN > 48 h. We identified MV patients in circulatory shock to evaluate the association between the timing of EN initiation and clinical outcomes. The regression analysis model controlled for age, mNUTRIC score, APACHE II score, sepsis, and Site.

Results

We included 626 patients, from 52 ICUs in 14 countries. Median age was 60 years [18–93], 55% had septic shock, 99% received norepinephrine alone, 91% received EN alone, and 50.3% were randomized to a usual protein dose. Forty-two percent of EEN patients had persistent organ dysfunction syndrome plus death at day 28, compared to 53% in the DEN group (p = 0.04). EEN was associated with more ICU-free days (9.3 ± 9.2 vs. 5.7 ± 7.9, p = 0.0002), more days alive and free of vasopressors (7.1 ± 3.1 vs. 6.3 ± 3.2, p = 0.007), and shorter duration of MV among survivors (9.8 ± 10.9 vs. 13.8 ± 14.5, p = 0.0002). This trend was no longer observed in the adjusted analysis. There were no differences in ICU/60-day mortality or feeding intolerance rates between groups.

Conclusion

In MV patients with circulatory shock, EEN, as compared to DEN, was associated with improved clinical outcomes, but no longer when adjusting for illness severity. RCTs comparing the efficacy of EEN to DEN in MV patients with circulatory shock are warranted.

Incidence and risk factors of nasogastric feeding intolerance in moderately-severe to severe acute pancreatitis

Background

The importance of enteral nutrition (EN) in acute pancreatitis (AP) has been emphasised. Nasogastric (NG) feeding has been the preferred route for EN delivery in most AP patients intolerant to oral intake. However, gastric feeding intolerance (GFI) was frequently reported, especially in patients with more severe diseases. This study aimed to investigate the incidence and risk factors for GFI in moderately-severe to severe AP.

Methods

This is a single-centre, retrospective study. All the data were extracted from an electronic database from April 2020 to May 2021. Data were prospectively collected during hospitalisation. Patients diagnosed with moderately-severe to severe AP and admitted within seven days from the onset of abdominal pain were assessed for eligibility. Patients who showed signs of intolerance to gastric feeding and required switching to nasojejunal (NJ) feeding were deemed GFI. Multivariable logistic regression was performed to assess potential risk factors of GFI.

Results

A total of 93 patients were analysed, of whom 24 were deemed GFI (25.8%), and the rest tolerated NG feeding well (n = 69). In patients with GFI, the median time of switching to NJ feeding was five days (interquartile range: 4–7 days) after admission. The multivariable analysis showed that respiratory failure (odds ratio = 3.135, 95% CI: 1.111–8.848, P = 0.031) was an independent risk factor for GFI.The mean daily energy delivery in the following three days after switching to NJ feeding was significantly higher than the first three days after initiation of NG feeding in patients with GFI [920.83 (493.33–1326) vs. 465 (252.25–556.67) kcal, P < 0.001].

Conclusion

GFI is common in moderately-severe to severe AP patients with an incidence of 25.8%, and the presence of respiratory failure may increase the risk of GFI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02403-w.

When a calorie isn't just a calorie: a revised look at nutrition in critically ill patients with sepsis and acute kidney injury

PURPOSE OF REVIEW

To discuss how nutritional management could be optimized to promote protective metabolism in sepsis and associated acute kidney injury.

RECENT FINDINGS

Recent evidence suggests that sepsis is a metabolically distinct critical illness and that certain metabolic alterations, such as activation of fasting metabolism, may be protective in bacterial sepsis. These findings may explain the lack of survival benefit in recent randomized controlled trials of nutrition therapy for critical illness. These trials are limited by cohort heterogeneity, combining both septic and nonseptic critical illness, and the use of inaccurate caloric estimates to determine energy requirements. These energy estimates are also unable to provide information on specific substrate preferences or the capacity for substrate utilization. As a result, high protein feeding beyond the capacity for protein synthesis could cause harm in septic patients. Excess glucose and insulin exposures suppress fatty acid oxidation, ketogenesis and autophagy, of which emerging evidence suggest are protective against sepsis associated organ damage such as acute kidney injury.

SUMMARY

Distinguishing pathogenic and protective sepsis-related metabolic changes are critical to enhancing and individualizing nutrition management for critically ill patients.

Parenteral Nutrition Total Energy Dosing and Risk for Central Line-Associated Bloodstream Infection: A Case-Control Study

BACKGROUND

Central line-associated bloodstream infection (CLABSI) is a complication of central venous access devices used for parenteral nutrition (PN). PN overfeeding is associated with increased adverse effects; however, whether risk for CLABSI is influenced by PN dosing is uncertain.

OBJECTIVE

The purpose of the study was to assess differences in CLABSI risk associated with recommended total energy dosing in hospitalized adult patients receiving PN.

METHODS

A case-control study was conducted in a single United States Veterans Health Administration health system to assess the potential CLABSI risk factor of weight-based PN kilocalorie dosing. Hospitalized adult patients who developed CLABSI while receiving PN were identified and compared to a control group of patients who did not develop CLABSI. The exposures evaluated were overfeeding, defined as greater than 30 kcal/kg/day, and underfeeding, defined as less than 20 kcal/kg/day.

RESULTS

Twenty-nine cases of CLABSI were identified and compared with 274 controls. Odds of CLABSI were significantly higher in patients receiving greater than 30 kcal/kg/day (OR, 3.63; 95% CI, 1.55-8.48; P < .01). No significant difference in odds was found for patients receiving less than 20 kcal/kg/day (OR, .74; 95% CI, 0.21-2.57; P = .63).

CONCLUSION

Increased risk for CLABSI in hospitalized adult patients receiving PN was found to be associated with overfeeding, but not underfeeding. These results may aid clinicians in the management of patients requiring PN and in the generation of hypothesis for future investigations.

Catabolism in Critical Illness

OBJECTIVES

Ongoing risk of death and poor functional outcomes are important consequences of prolonged critical illness. Characterizing the catabolic phenotype of prolonged critical illness could illuminate biological processes and inform strategies to attenuate catabolism. We aimed to examine if urea-to-creatinine ratio, a catabolic signature of prolonged critical illness, was associated with mortality after the first week of ICU stay.

DESIGN

Reanalysis of multicenter randomized trial of glutamine supplementation in critical illness (REducing Deaths due to OXidative Stress [REDOXS]).

SETTING

Multiple adult ICUs.

PATIENTS

Adult patients admitted to ICU with two or more organ failures related to their acute illness and surviving to day 7.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The association between time-varying urea-to-creatinine ratio and 30-day mortality was tested using Bayesian joint models adjusted for prespecified-covariates (age, kidney replacement therapy, baseline Sequential Organ Failure Assessment, dietary protein [g/kg/d], kidney dysfunction, and glutamine-randomization). From 1,021 patients surviving to day 7, 166 (16.3%) died by day 30. After adjustment in a joint model, a higher time-varying urea-to-creatinine ratio was associated with increased mortality (hazard ratio [HR], 2.15; 95% credible interval, 1.66-2.82, for a two-fold greater urea-to-creatinine ratio). This association persisted throughout the 30-day follow-up. Mediation analysis was performed to explore urea-to-creatinine ratio as a mediator-variable for the increased risk of death reported in REDOXS when randomized to glutamine, an exogenous nitrogen load. Urea-to-creatinine ratio closest to day 7 was estimated to mediate the risk of death associated with randomization to glutamine supplementation (HR, 1.20; 95% CI, 1.04-1.38; p = 0.014), with no evidence of a direct effect of glutamine (HR, 0.90; 95% CI, 0.62-1.30; p = 0.566).

CONCLUSIONS

The catabolic phenotype measured by increased urea-to-creatinine ratio is associated with increased risk of death during prolonged ICU stay and signals the deleterious effects of glutamine administration in the REDOXS study. Urea-to-creatinine ratio is a promising catabolic signature and potential interventional target.

Patient perceptions of the challenges of recruitment to a renal randomised trial registry: a pilot questionnaire-based study

Background

Randomised controlled trials (RCTs) are the gold standard for demonstrating the efficacy of new therapies. However, issues of external validity often affect result application to real-world settings. Using registries to conduct RCTs is a reasonably new practice, but is appealing because it combines the benefits of both observational studies and RCTs. There is limited literature on patient motivators, barriers, and consent to registries for conducting RCTs. The purpose of our study was to establish the factors that motivate and/or inhibit patients from joining a registry for RCTs and to determine what information matters to patients when making an enrolment decision to participate in such a registry.

Methods

We conducted a cross-sectional questionnaire-based study at a dialysis centre in Southwest Ireland representing a catchment patient population of approximately 430,000. Quantitative data were coded and analysed in SPSS (v16). Descriptive statistics were produced, and open-ended questions were analysed by thematic analysis.

Results

Eighty-seven patients completed the questionnaire. Reasons for participation in a registry included personal and altruistic benefits. Barriers to participation were time and travel requirements associated with registry participation, data safety concerns, risks, side effects, and concerns that registry participation would impact current treatment. Although 29.8% of patients expressed concern regarding their data being stored in a registry, 79.3% were still willing to consent to have their data uploaded and stored in a registry for conducting RCTs. It was important to patients to have their GP (general practitioner) involved in the decision to participate, despite little day-to-day contact with their GP for renal dialysis management.

Conclusion

Challenges to recruitment to registries for RCTs exist, but addressing the identified concerns of potential participants may aid patients in making a more informed enrolment decision and may improve recruitment to registries, and by extension, to RCTs conducted using the registry.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05526-9.

Nutrition in the Intensive Care Unit-A Narrative Review

Background: While consent exists, that nutritional status has prognostic impact in the critically ill, the optimal feeding strategy has been a matter of debate. Methods: Narrative review of the recent evidence and international guideline recommendations focusing on basic principles of nutrition in the ICU and the treatment of specific patient groups. Covered topics are: the importance and diagnosis of malnutrition in the ICU, the optimal timing and route of nutrition, energy and protein requirements, the supplementation of specific nutrients, as well as monitoring and complications of a Medical Nutrition Therapy (MNT). Furthermore, this review summarizes the available evidence to optimize the MNT of patients grouped by primarily affected organ system. Results: Due to the considerable heterogeneity of the critically ill, MNT should be carefully adapted to the individual patient with special focus on phase of critical illness, metabolic tolerance, leading symptoms, and comorbidities. Conclusion: MNT in the ICU is complex and requiring an interdisciplinary approach and frequent reevaluation. The impact of personalized and disease-specific MNT on patient-centered clinical outcomes remains to be elucidated.

Case presentation and panel discussion: critical illness

Despite a mounting evidentiary base, controversies surrounding critical care nutrition support persist. Anchored by a case of a 60-year-old male with esophageal cancer who develops acute hypoxemic respiratory failure and septic shock, five panelists from the ASPEN 2021 Pre-Conference discuss key clinical dilemmas in critical care nutrition, including hierarchy of evidence, bedside evaluation of malnutrition, optimal protein dose, use of fiber, and therapies targeting gut function and gut microbiota persist. This article is protected by copyright. All rights reserved.

The effect of higher versus lower protein delivery in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Background

The optimal protein dose in critical illness is unknown. We aim to conduct a systematic review of randomized controlled trials (RCTs) to compare the effect of higher versus lower protein delivery (with similar energy delivery between groups) on clinical and patient-centered outcomes in critically ill patients.

Methods

We searched MEDLINE, EMBASE, CENTRAL and CINAHL from database inception through April 1, 2021.We included RCTs of (1) adult (age ≥ 18) critically ill patients that (2) compared higher vs lower protein with (3) similar energy intake between groups, and (4) reported clinical and/or patient-centered outcomes. We excluded studies on immunonutrition. Two authors screened and conducted quality assessment independently and in duplicate. Random-effect meta-analyses were conducted to estimate the pooled risk ratio (dichotomized outcomes) or mean difference (continuous outcomes).

Results

Nineteen RCTs were included (n = 1731). Sixteen studies used primarily the enteral route to deliver protein. Intervention was started within 72 h of ICU admission in sixteen studies. The intervention lasted between 3 and 28 days. In 11 studies that reported weight-based nutrition delivery, the pooled mean protein and energy received in higher and lower protein groups were 1.31 ± 0.48 vs 0.90 ± 0.30 g/kg and 19.9 ± 6.9 versus 20.1 ± 7.1 kcal/kg, respectively. Higher vs lower protein did not significantly affect overall mortality [risk ratio 0.91, 95% confidence interval (CI) 0.75–1.10, p = 0.34] or other clinical or patient-centered outcomes. In 5 small studies, higher protein significantly attenuated muscle loss (MD −3.44% per week, 95% CI −4.99 to −1.90; p < 0.0001).

Conclusion

In critically ill patients, a higher daily protein delivery was not associated with any improvement in clinical or patient-centered outcomes. Larger, and more definitive RCTs are needed to confirm the effect of muscle loss attenuation associated with higher protein delivery.

PROSPERO registration number: CRD42021237530

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03693-4.

Nutritional Risk at intensive care unit admission and outcomes in survivors of critical illness

BACKGROUND AND AIMS

Risk factors for poor outcomes after critical illness are incompletely understood. While nutritional risk is associated with mortality in critically ill patients, its association with disability, cognitive, and health-related quality of life is unclear in survivors of critical illness. This study's objective was to determine whether greater nutritional risk at ICU admission is associated with greater disability, worse cognition, and worse HRQOL at 3 and 12-month follow-up.

METHODS

We enrolled adults (≥18 years of age) with respiratory failure or shock treated in medical and surgical intensive care units from two U.S. centers. We measured nutritional risk using the modified Nutrition Risk in Critically Ill (mNUTRIC) score (range 0-9 [highest risk]) at intensive care unit admission. We measured associations between mNUTRIC scores and discharge destination, disability in basic activities of daily living (ADLs) using the Katz ADL, instrumental ADLs using the Functional Activities Questionnaire (FAQ), global cognition using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), executive function using the Trail Making Test Part B (Trails B), and health-related quality of life using the SF-36, adjusting for sex, education, BMI, baseline frailty, disability, and cognition, severity of illness, days of delirium, coma, and mechanical ventilation.

RESULTS

Of the 821 patients enrolled in the ICU, 636 patients survived to hospital discharge. We assessed outcomes in 448 of 535 survivors (84%) at 3 months and 382 of 476 survivors (80%) at 12 months. Higher mNUTRIC scores predicted greater odds of discharge to an institution (OR 2.0, 95% CI: 1.6 to 2.6; P < 0.01). Higher mNUTRIC scores were associated with a trend towards greater disability in basic activities of daily living (IRR 1.3, 95% CI 1.0 to 1.7) at 3 months that did not reach significance (p = 0.09) with no association demonstrated at 12 months. There were no associations between mNUTRIC scores and FAQ, RBANS, or Trails B scores. mNUTRIC scores were inconsistently associated with SF-36 physical and mental component scale scores.

CONCLUSIONS

Greater nutritional risk at ICU admission is associated with disability in survivors of critical illness. Future studies should evaluate interventions in those at high nutritional risk as a means to speed recovery.

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.

Full Versus Trophic Feeds in Critically Ill Adults with High and Low Nutritional Risk Scores: A Randomized Controlled Trial

Although energy intake might be associated with clinical outcomes in critically ill patients, it remains unclear whether full or trophic feeding is suitable for critically ill patients with high or low nutrition risk. We conducted a prospective study to determine which feeding energy intakes were associated with clinical outcomes in critically ill patients with high or low nutrition risk. This was an investigator-initiated, single center, single blind, randomized controlled trial. Critically ill patients were allocated to either high or low nutrition risk based on their Nutrition Risk in the Critically Ill score, and then randomized to receive either the full or the trophic feeding. The feeding procedure was administered for six days. No significant differences were observed in hospital, 14-day and 28-day mortalities, the length of ventilator dependency, or ICU and hospital stay among the four groups. There were no associations between energy and protein intakes and hospital, 14-day and 28-day mortalities in any of the four groups. However, protein intake was positively associated with the length of hospital stay and ventilator dependency in patients with low nutrition risk receiving trophic feeding. Full or trophic feeding in critically ill patients showed no associations with clinical outcomes, regardless of nutrition risk.

Association between ultrasound quadriceps muscle status with premorbid functional status and 60-day mortality in mechanically ventilated critically ill patient: A single-center prospective observational study

BACKGROUND & AIMS

In critically ill patients, direct measurement of skeletal muscle using bedside ultrasound (US) may identify a patient population that might benefit more from optimal nutrition practices. When US is not available, survey measures of nutrition risk and functional status that are associated with muscle status may be used to identify patients with low muscularity. This study aims to determine the association between baseline and changing ultrasound quadriceps muscle status with premorbid functional status and 60-day mortality.

METHODS

This single-center prospective observational study was conducted in a general ICU. Mechanically ventilated critically ill adult patients (age ≥18 years) without pre-existing systemic neuromuscular diseases and expected to stay for ≥96 h in the ICU were included. US measurements were performed within 48 h of ICU admission (baseline), at day 7, day 14 of ICU stay and at ICU discharge (if stay >14 days). Quadriceps muscle layer thickness (QMLT), rectus femoris cross sectional area (RFCSA), vastus intermedius pennation angle (PA) and fascicle length (FL), and rectus femoris echogenicity (mean and standard deviation [SD]) were measured. Patients' next-of-kin were interviewed by using established questionnaires for their pre-hospitalization nutritional risk (nutrition risk screening-2002) and functional status (SARC-F, clinical frailty scale [CFS], Katz activities of daily living [ADL] and Lawton Instrumental ADL).

RESULTS

Ninety patients were recruited. A total of 86, 53, 24 and 10 US measures were analyzed, which were performed at a median of 1, 7, 14 and 22 days from ICU admission, respectively. QMLT, RFCSA and PA reduced significantly over time. The overall trend of change of FL was not significant. The only independent predictor of 60-day mortality was the change of QMLT from baseline to day 7 (adjusted odds ratio 0.95 for every 1% less QMLT loss, 95% confidence interval 0.91-0.99; p = 0.02). Baseline measures of high nutrition risk (modified nutrition risk in critically ill ≥5), sarcopenia (SARC-F ≥4) and frailty (CFS ≥5) were associated with lower baseline QMLT, RFCSA and PA and higher 60-day mortality.

CONCLUSIONS

Every 1% loss of QMLT over the first week of critical illness was associated with 5% higher odds of 60-day mortality. SARC-F, CFS and mNUTRIC are associated with quadriceps muscle status and 60-day mortality and may serve as a potential simple and indirect measures of premorbid muscle status at ICU admission.

Biomarkers in critical care nutrition

The goal of nutrition support is to provide the substrates required to match the bioenergetic needs of the patient and promote the net synthesis of macromolecules required for the preservation of lean mass, organ function, and immunity. Contemporary observational studies have exposed the pervasive undernutrition of critically ill patients and its association with adverse clinical outcomes. The intuitive hypothesis is that optimization of nutrition delivery should improve ICU clinical outcomes. It is therefore surprising that multiple large randomized controlled trials have failed to demonstrate the clinical benefit of restoring or maximizing nutrient intake. This may be in part due to the absence of biological markers that identify patients who are most likely to benefit from nutrition interventions and that monitor the effects of nutrition support. Here, we discuss the need for practical risk stratification tools in critical care nutrition, a proposed rationale for targeted biomarker development, and potential approaches that can be adopted for biomarker identification and validation in the field.

Meeting nutritional targets of critically ill patients by combined enteral and parenteral nutrition: review and rationale for the EFFORTcombo trial

While medical nutrition therapy is an essential part of the care for critically ill patients, uncertainty exists about the right form, dosage, timing and route in relation to the phases of critical illness. As enteral nutrition (EN) is often withheld or interrupted during the intensive care unit (ICU) stay, combined EN and parenteral nutrition (PN) may represent an effective and safe option to achieve energy and protein goals as recommended by international guidelines. We hypothesise that critically ill patients at high nutritional risk may benefit from such a combined approach during their stay on the ICU. Therefore, we aim to test if an early combination of EN and high-protein PN (EN+PN) is effective in reaching energy and protein goals in patients at high nutritional risk, while avoiding overfeeding. This approach will be tested in the here-presented EFFORTcombo trial. Nutritionally high-risk ICU patients will be randomised to either high (≥2·2 g/kg per d) or low protein (≤1·2 g/kg per d). In the high protein group, the patients will receive EN+PN; in the low protein group, patients will be given EN alone. EN will be started in accordance with international guidelines in both groups. Efforts will be made to reach nutrition goals within 48-96 h. The efficacy of the proposed nutritional strategy will be tested as an innovative approach by functional outcomes at ICU and hospital discharge, as well as at a 6-month follow-up.

Differential Effects of Early Energy and Protein Inadequacies on the Outcome of Critically Ill Patients

BACKGROUND

Differential effects of energy and protein inadequacies of intensive care unit (ICU) patients in first 72 hours are unknown.

METHODS

We included all adult patients receiving mechanical ventilation (MV) > 72 hours between August 2012 and December 2014. Energy and protein doses were 25 kcal/kg/day and 1.5 g/kg/day, respectively. We used multivariable Cox regression analysis for 28-day mortality and competing risks regression analysis for post-ICU length of stay (LOS) in hospital survivors.

RESULTS

In 421 patients (male 63.4%, mean age 62 ± 15.1 years) the energy and protein adequacies at 72 hours were 70% and 56%, respectively. Non-survivors by day 28 were started on feeding significantly later (median, 14.13 (5.48-33.78) versus 9.25 (5.45-16.58) hours, P = .003) and received lower energy (mean, 0.57 ± 0.36 versus 0.76 ± 0.29, P < 0.001) and protein (median, 0.51 (0.13-0.74) versus 0.61 (0.40-0.84), P < 0.001) adequacies at day 7 (same effect seen at 72 hours, P < 0.001). Higher energy adequacy at 72 hours was associated with lower mortality (hazard ratio [HR], 0.39 (95% CI 0.20-0.75), P = 0.004); the lowest mortality was seen between 61% and 70% energy adequacies. No such association was seen with protein adequacy. In 280 hospital survivors, higher energy adequacy at 72 hours (subdistribution HR 1.63; 95% CI, 1.06-2.50, P = 0.025) was significantly associated with shorter post-ICU LOS. No such effect was seen with protein adequacy.

CONCLUSION

Higher energy but not protein adequacy at 72 hours of MV was associated with improved patient-centric outcomes.

Outcomes Six Months after Delivering 100% or 70% of Enteral Calorie Requirements during Critical Illness (TARGET). A Randomized Controlled Trial

Rationale: The long-term effects of delivering approximately 100% of recommended calorie intake via the enteral route during critical illness compared with a lesser amount of calories are unknown.Objectives: Our hypotheses were that achieving approximately 100% of recommended calorie intake during critical illness would increase quality-of-life scores, return to work, and key life activities and reduce death and disability 6 months later.Methods: We conducted a multicenter, blinded, parallel group, randomized clinical trial, with 3,957 mechanically ventilated critically ill adults allocated to energy-dense (1.5 kcal/ml) or routine (1.0 kcal/ml) enteral nutrition.Measurements and Main Results: Participants assigned energy-dense nutrition received more calories (percent recommended energy intake, mean [SD]; energy-dense: 103% [28] vs. usual: 69% [18]). Mortality at Day 180 was similar (560/1,895 [29.6%] vs. 539/1,920 [28.1%]; relative risk 1.05 [95% confidence interval, 0.95-1.16]). At a median (interquartile range) of 185 (182-193) days after randomization, 2,492 survivors were surveyed and reported similar quality of life (EuroQol five dimensions five-level quality-of-life questionnaire visual analog scale, median [interquartile range]: 75 [60-85]; group difference: 0 [95% confidence interval, 0-0]). Similar numbers of participants returned to work with no difference in hours worked or effectiveness at work (n = 818). There was no observed difference in disability (n = 1,208) or participation in key life activities (n = 705).Conclusions: The delivery of approximately 100% compared with 70% of recommended calorie intake during critical illness does not improve quality of life or functional outcomes or increase the number of survivors 6 months later.

Forty-Third ASPEN Presidential Address: "Our Time Is Now-Challenges and Strategies for the Field of Nutrition"

I am grateful for this opportunity to address the ASPEN community and the international colleagues gathered at the ASPEN 2019 Nutrition Science and Practice Meeting. I have used this platform to revisit some of the historical beginnings of our field and our organization, and illustrate some of the lessons learned. I have outlined 5 challenges facing the field of nutrition during our times and discussed strategies that might help navigate them. These challenges are, healthcare finance, biotechnology disruption, safety, research, and knowledge transfer. These challenges will require nutrition providers to adapt to changing times. We must be prepared to show the "value" of the care provided. The impact of nutrition therapies must be unequivocally demonstrated on meaningful patient outcomes, thereby emphasizing the relevance and value of the services we provide. As clinical nutrition professionals, we must embrace the rapid pace of biotechnology advance and harness its power to assist us and our patients. The provision of safe nutrition care to our patients is the fundamental aspect of the ASPEN vision. I remain confident in our collective strengths, our sense of purpose, and our ability to rise above the challenges we face. Together with our global partners we will deliver on the promise of safe, efficacious, low-cost, and high-quality nutrition that will improve patient outcomes and population health.

Older Adults in the Cardiac Intensive Care Unit: Factoring Geriatric Syndromes in the Management, Prognosis, and Process of Care: A Scientific Statement From the American Heart Association

Longevity is increasing, and more adults are living to the stage of life when age-related biological factors determine a higher likelihood of cardiovascular disease in a distinctive context of concurrent geriatric conditions. Older adults with cardiovascular disease are frequently admitted to cardiac intensive care units (CICUs), where care is commensurate with high age-related cardiovascular disease risks but where the associated geriatric conditions (including multimorbidity, polypharmacy, cognitive decline and delirium, and frailty) may be inadvertently exacerbated and destabilized. The CICU environment of procedures, new medications, sensory overload, sleep deprivation, prolonged bed rest, malnourishment, and sleep is usually inherently disruptive to older patients regardless of the excellence of cardiovascular disease care. Given these fundamental and broad challenges of patient aging, CICU management priorities and associated decision-making are particularly complex and in need of enhancements. In this American Heart Association statement, we examine age-related risks and describe some of the distinctive dynamics pertinent to older adults and emerging opportunities to enhance CICU care. Relevant assessment tools are discussed, as well as the need for additional clinical research to best advance CICU care for the already dominating and still expanding population of older adults.

Protein intake and outcome in critically ill patients

PURPOSE OF REVIEW

The objective of this review is to describe the impact of protein intake on the outcomes of critically ill patients in the literature published in the preceding 2 years.

RECENT FINDINGS

Observational studies showed inconsistent results regarding the association of higher protein intake and outcomes of critically ill patients. Randomized controlled trials that directly compared higher versus lower protein intake in ICU patients are scarce, varied considerably in their designs and primary outcomes, and generally had relatively small differences in the amount of delivered protein between the study arms. Systematic reviews of existing studies showed no difference in mortality with higher protein intake. In addition, there is uncertainty regarding high protein provision in the early phase of critical illness.

SUMMARY

The optimal amount of protein intake in critically ill patients remains largely unclear and is considered a high priority for research. Ongoing clinical trials are likely to provide additional evidence on several important questions including the dose, timing, type of protein and the interaction with caloric intake and exercise.

Systematic Review With Meta-Analysis of Patient-Centered Outcomes, Comparing International Guideline-Recommended Enteral Protein Delivery With Usual Care

BACKGROUND

International guidelines recommend that protein be administered enterally to critically ill patients at doses between 1.2 and 2 g/kg per day Observational data indicate that patients frequently receive less protein. The aim of this systematic review was to evaluate patient-centered outcomes with guideline-recommended enteral protein compared with usual care.

METHODS

A systematic review was performed of randomized controlled trials including critically ill adult patients provided predominately enteral nutrition with mean protein at ≥1.2 g/kg per day (intervention) and <1.2 g/kg per day (comparator). Random-effects models were applied for outcomes reported in ≥3 trials.

RESULTS

Of 1375 abstracts, 69 full-text articles were reviewed, and 6 trials meet the inclusion criteria, including 511 patients. The intervention group received a mean (SD) of 1.3 (0.08) g/kg per day, and the comparator group received 0.75 (0.15) g/kg per day protein. Insufficient data were available for meta-analyses on the primary outcome (muscle mass or strength). According to our meta-analyses, mortality at 28 days (5 studies) (risk ratio 0.92 [95% Cl 0.63-1.35], P = .66) and the durations of intensive care unit (6 studies) and hospital admission (4 studies) were similar between the intervention and comparator, with some uncertainty due to sample sizes and heterogeneity.

CONCLUSION

There are insufficient data to conclude whether protein provision within the current international guideline recommendations improves outcomes. In a limited dataset, enteral protein intakes near the lower level of current recommendations do not appear to reduce admission duration or mortality when compared with usual care in critically ill.