Withholding parenteral nutrition during critical illness increases plasma bilirubin but lowers the incidence of biliary sludge

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

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

Our Scientific Journey through the Ups and Downs of Blood Glucose Control in the ICU

This article tells the story of our long search for the answer to one question: Is stress hyperglycemia in critically ill patients adaptive or maladaptive? Our earlier work had suggested the lack of hepatic insulin effect and hyperglycemia as jointly predicting poor outcome. Therefore, we hypothesized that insulin infusion to reach normoglycemia, tight glucose control, improves outcome. In three randomized controlled trials (RCTs), we found morbidity and mortality benefit with tight glucose control. Moving from the bed to the bench, we attributed benefits to the prevention of glucose toxicity in cells taking up glucose in an insulin-independent, glucose concentration gradient-dependent manner, counteracted rather than synergized by insulin. Several subsequent RCTs did not confirm benefit, and the large Normoglycemia in Intensive Care Evaluation-Survival Using Glucose Algorithm Regulation, or "NICE-SUGAR," trial found increased mortality with tight glucose control associated with severe hypoglycemia. Our subsequent clinical and mechanistic research revealed that early use of parenteral nutrition, the context of our initial RCTs, had been a confounder. Early parenteral nutrition (early-PN) aggravated hyperglycemia, suppressed vital cell damage removal, and hampered recovery. Therefore, in our next and largest "TGC-fast" RCT, we retested our hypothesis, without the use of early-PN and with a computer algorithm for tight glucose control that avoided severe hypoglycemia. In this trial, tight glucose control prevented kidney and liver damage, though with much smaller effect sizes than in our initial RCTs without affecting mortality. Our quest ends with the strong recommendation to omit early-PN for patients in the ICU, as this reduces need of blood glucose control and allows cellular housekeeping systems to play evolutionary selected roles in the recovery process. Once again, less is more in critical care.

The Hypothalamus-pituitary-adrenocortical Response to Critical Illness: A Concept in Need of Revision

Based on insights obtained during the past decade, the classical concept of an activated hypothalamus-pituitary-adrenocortical axis in response to critical illness is in need of revision. After a brief central hypothalamus-pituitary-adrenocortical axis activation, the vital maintenance of increased systemic cortisol availability and action in response to critical illness is predominantly driven by peripheral adaptations rather than by an ongoing centrally activated several-fold increased production and secretion of cortisol. Besides the known reduction of cortisol-binding proteins that increases free cortisol, these peripheral responses comprise suppressed cortisol metabolism in liver and kidney, prolonging cortisol half-life, and local alterations in expression of 11βHSD1, glucocorticoid receptor-α (GRα), and FK506 binding protein 5 (FKBP51) that appear to titrate increased GRα action in vital organs and tissues while reducing GRα action in neutrophils, possibly preventing immune-suppressive off-target effects of increased systemic cortisol availability. Peripherally increased cortisol exerts negative feed-back inhibition at the pituitary level impairing processing of pro-opiomelanocortin into ACTH, thereby reducing ACTH-driven cortisol secretion, whereas ongoing central activation results in increased circulating pro-opiomelanocortin. These alterations seem adaptive and beneficial for the host in the short term. However, as a consequence, patients with prolonged critical illness who require intensive care for weeks or longer may develop a form of central adrenal insufficiency. The new findings supersede earlier concepts such as "relative," as opposed to "absolute," adrenal insufficiency and generalized systemic glucocorticoid resistance in the critically ill. The findings also question the scientific basis for broad implementation of stress dose hydrocortisone treatment of patients suffering from acute septic shock solely based on assumption of cortisol insufficiency.

Immunosuppressive effects of circulating bile acids in human endotoxemia and septic shock: patients with liver failure are at risk

BACKGROUND

Sepsis-induced immunosuppression is a frequent cause of opportunistic infections and death in critically ill patients. A better understanding of the underlying mechanisms is needed to develop targeted therapies. Circulating bile acids with immunosuppressive effects were recently identified in critically ill patients. These bile acids activate the monocyte G-protein coupled receptor TGR5, thereby inducing profound innate immune dysfunction. Whether these mechanisms contribute to immunosuppression and disease severity in sepsis is unknown. The aim of this study was to determine if immunosuppressive bile acids are present in endotoxemia and septic shock and, if so, which patients are particularly at risk.

METHODS

To induce experimental endotoxemia in humans, ten healthy volunteers received 2 ng/kg E. coli lipopolysaccharide (LPS). Circulating bile acids were profiled before and after LPS administration. Furthermore, 48 patients with early (shock onset within < 24 h) and severe septic shock (norepinephrine dose > 0.4 μg/kg/min) and 48 healthy age- and sex-matched controls were analyzed for circulating bile acids. To screen for immunosuppressive effects of circulating bile acids, the capability to induce TGR5 activation was computed for each individual bile acid profile by a recently published formula.

RESULTS

Although experimental endotoxemia as well as septic shock led to significant increases in total bile acids compared to controls, this increase was mild in most cases. By contrast, there was a marked and significant increase in circulating bile acids in septic shock patients with severe liver failure compared to healthy controls (61.8 µmol/L vs. 2.8 µmol/L, p = 0.0016). Circulating bile acids in these patients were capable to induce immunosuppression, as indicated by a significant increase in TGR5 activation by circulating bile acids (20.4% in severe liver failure vs. 2.8% in healthy controls, p = 0.0139).

CONCLUSIONS

Circulating bile acids capable of inducing immunosuppression are present in septic shock patients with severe liver failure. Future studies should examine whether modulation of bile acid metabolism can improve the clinical course and outcome of sepsis in these patients.

Inflammatory processes involved in the alteration of liver function biomarkers in adult hospitalized patients treated with parenteral nutrition

Introduction

Liver damage has been associated with the accumulation of phytosterols (PS) in patients treated with parenteral nutrition (PN). We aimed to study the association of inflammatory markers with liver function biomarker (LFB) alterations in patients treated with PN containing PS.

Materials and methods

Prospective observational study. Simple linear and stepwise multiple linear regression tests and interactions were performed.

Results

Nineteen patients were included. In the multivariable model, determinations based on LFBs as dependent and phytosterols (and their fractions) as independent variables showed an association between increases in gamma-glutamyltransferase (GGT) and lanosterol (p < 0.001), stigmasterol (p < 0.001), interleukin-10 (IL-10) × total phytosterols (Phyt) (p < 0.009), tumor necrosis factor-α (TNF-α) × Phyt (p < 0.002), IL-10 × sitosterol (p < 0.002), TNF-α × sitosterol (p < 0.001), IL-10 × campesterol (p < 0.033), IL-10 (p < 0.006 and p < 0.015), TNF-α (p < 0.048 and p < 0.027). Increases in alanine aminotransferase (ALT) were associated with Phyt (p < 0.006), lanosterol (p < 0.016), C-reactive protein (CRP) × campesterol (p < 0.001), interleukin-6 (IL-6) × stigmasterol (p < 0.030), CRP (p < 0.08), and IL-6 (p < 0.042). Alkaline phosphatase (AP) increases were associated with CRP (p < 0.002).

Discussion

Inflammation in the presence of plasmatic PS seems to have a synergistic effect in impairing liver function, mainly altering GGT but also ALT.

Acute liver injury in COVID-19 patients hospitalized in the intensive care unit: Narrative review

In recent years, humanity has been confronted with a global pandemic due to coronavirus disease 2019 (COVID-19), which has caused an unprecedented health and economic crisis worldwide. Apart from the respiratory symptoms, which are considered the principal manifestations of COVID-19, it has been recognized that COVID-19 constitutes a systemic inflammatory process affecting multiple organ systems. Across the spectrum of organ involvement in COVID-19, acute liver injury (ALI) has been gradually gaining increasing attention by the international scientific community. COVID-19 associated liver impairment can affect a considerable proportion of COVID-19 patients and seems to correlate with the severity of the disease course. Indeed, COVID-19 patients hospitalized in the intensive care unit (ICU) run a greater risk of developing ALI due to the severity of their clinical condition and in the context of multi-organ failure. The putative pathophysiological mechanisms of COVID-19 induced ALI in ICU patients remain poorly understood and appear to be multifactorial in nature. Several theories have been proposed to explain the occurrence of ALI in the ICU setting, such as hypoperfusion and ischemia due to hemodynamic instability, passive liver congestion as a result of congestive heart failure, ischemia-reperfusion injury, hypoxia due to respiratory failure, mechanical ventilation itself, sepsis and septic shock, cytokine storm, endotheliitis with concomitant coagulopathy, drug-induced liver injury, parenteral nutrition and direct cytopathic viral effect. It should be noted that no specific therapy for COVID-19 induced ALI exists. Therefore, the therapeutic approach lies in preventive measures and is exclusively supportive once ALI ensues. The aim of the current review is to scrutinize the existing evidence on COVID-19 associated ALI in ICU patients, explore its clinical implications, shed light on the underlying pathophysiological mechanisms and propose potential therapeutic approaches. Ongoing research on the particular scientific field will further elucidate the pathophysiology behind ALI and address unresolved issues, in the hope of mitigating the tremendous health consequences imposed by COVID-19 on ICU patients.

Evaluation of qSOFA score, and conjugated bilirubin and creatinine levels for predicting 28‑day mortality in patients with sepsis

Sepsis is a dangerous disease that develops rapidly and has a high mortality rate. A timely and accurate assessment of the patient's condition is beneficial in improving prognosis and reducing mortality. Therefore, the present study was designed to investigate the potential association between quick sequential organ failure assessment (qSOFA) scores and biochemical indicators, such as conjugated bilirubin (CB) and creatinine levels, with the 28-day prognosis of patients with sepsis in a retrospective observational study. All cases were divided into survival and non-survival groups on the 28th day after diagnosis. The qSOFA scores, and CB and creatinine levels were significantly higher in the non-survival group than in the survival group (both P<0.01). Cox regression models identified CB [hazard ratio (HR), 1.006; P=0.002] and creatinine levels (HR, 1.002; P=0.024) as independent factors affecting 28-day mortality. The area under the curve (AUC) for CB and creatinine levels plus qSOFA score was 0.792 (95% confidence interval, 0.745-0.834), which was larger than the values for CB level, creatinine level and qSOFA score alone (all P<0.01) in the prognosis of 28-day mortality. The cut-off value of CB and creatinine levels plus qSOFA score for the 28-day mortality was 0.275 (-2.466 + 0.012 x CB + 0.002 x creatinine + 1.289 x qSOFA). Patients with lower combined predictor values had a better prognosis as demonstrated by Kaplan-Meier survival curves (log-rank test, 10.060; P=0.002). In both the septic shock and sepsis groups, the combined predictor value was higher in the non-survival group than in the survival group (P<0.001). Therefore, an increase in the combined predictor value of CB and creatinine levels plus qSOFA score may be an important predictor of disease progression and prognosis in patients with sepsis and septic shock.

C-reactive protein rise in response to macronutrient deficit early in critical illness: sign of inflammation or mediator of infection prevention and recovery

PURPOSE

Withholding parenteral nutrition (PN) early in critical illness, late-PN, has shown to prevent infections despite a higher peak C-reactive protein (CRP). We investigated whether the accentuated CRP rise was caused by a systemic inflammatory effect mediated by cytokines or arose as a consequence of the different feeding regimens, and whether it related to improved outcome with late-PN.

METHODS

This secondary analysis of the EPaNIC-RCT first investigated, with multivariable linear regression analyses, determinants of late-PN-induced CRP rise and its association with cytokine responses (IL-6, IL-10, TNF-α) in matched early-PN and late-PN patients requiring intensive care for ≥ 3 days. Secondly, with multivariable logistic regression and Cox proportional-hazard analyses, we investigated whether late-PN-induced CRP rises mediated infection prevention and enhanced recovery or reflected an adverse effect counteracting such benefits of late-PN.

RESULTS

CRP peaked on day 3, higher with late-PN [216(152-274)mg/l] (n = 946) than with early-PN [181(122-239)mg/l] (n = 946) (p < 0.0001). Independent determinants of higher CRP rise were lower carbohydrate and protein intakes (p ≤ 0.04) with late-PN, besides higher blood glucose and serum insulin concentrations (p ≤ 0.01). Late-PN did not affect cytokines. Higher CRP rises were independently associated with more infections and lower likelihood of early ICU discharge (p ≤ 0.002), and the effect size of late-PN versus early-PN on these outcomes was increased rather than reduced after adjusting for CRP rise, not confirming a mediating role.

CONCLUSIONS

The higher CRP rise with late-PN, explained by the early macronutrient deficits, did not relate to cytokine responses and thus did not reflect more systemic inflammation. Instead of mediating clinical benefit on infection or recovery, the accentuated CRP rise appeared an adverse effect reducing such late-PN benefits.

Effect of Early Versus Delayed Parenteral Nutrition on the Health Outcomes of Critically Ill Adults: A Systematic Review

Objectives

This systematic review aims to evaluate and summarise the findings of all relevant studies which identified the effect of early vs delayed parenteral nutrition (PN), early PN vs early supplemental PN and early PN vs standard care for critically ill adults.

Methods

The literature search was undertaken using PubMed, Embase, Medline, Clinical Key, and Ovid discovery databases. The reference lists of studies published from 2000 till June 2020 were hand searched.

Result

On screening 2088 articles, a total of five RCTs with 6,277 patients were included in this review. Only one clinical trial compared early PN and late PN; the results reported significantly shorter periods in intensive care unit (ICU) stay (p=0.02) and less ICU related infections (p=0.008) in the late PN group compared to the Early PN group. Two trials compared total parenteral nutrition (TPN) and enteral nutrition (EN) +TPN groups. Both found a significantly longer hospital stay duration (p<0.05 and p<0.01) with a higher mortality rate in the TPN group compared to the EN+TPN group. A statistically significant improvement was observed in patients' quality of life receiving early PN compared to standard care (p=0.01). In contrast, no significant difference was found in the supplemental PN vs the standard care group.

Conclusion

The supplemental PN patients had shorter ICU stay and lower mortality rates than TPN. However, these findings should be interpreted carefully as included studies have different initiation timing of nutritional support, and the patients' diagnosis varied.

[Effects of cholestasis and hypoxic hepatitis on prognosis of ICU patients: a retrospective study based on MIMIC Ⅲ database]

OBJECTIVE

Abnormalities of liver-related indices are common in ICU patients, but the effects of cholestasis and hypoxic hepatitis in critically ill patients remains unclarified. The purpose of this study was to investigate the effects of cholestasis and hypoxic liver dysfunction on the prognosis of ICU patients.

METHODS

A retrospective study was conducted based on the data of patients admitted to the ICU for the first time between 2001 and 2011 archived in the MIMIC-Ⅲ database. The patients were divided into cholestasis, hypoxic hepatitis and control groups, and their 28-day case fatality rate as the primary outcome was compared among the groups.

RESULTS

A total of 5852 ICU patients were included in the analysis. The incidence of cholestasis and hypoxic liver dysfunction was 31.9% (1869/5852) and 17.9% (1046/5852), respectively. There was no significant difference in 28-day case fatality rate between cholestasis group and the control group. Compared with the control group, the patients with hypoxic hepatitis had a significantly higher 28-day case fatality rate (46% vs 35%, P &lt; 0.01), a higher hospital case fatality rate (40% vs 31%, P &lt; 0.01), and a higher ICU case fatality rate (35.7% vs 22.2%, P &lt; 0.01). Logistic regression analysis showed that lactic acid (LAC), aspartate transaminase (AST), and international standard ratio (INR) were independent risk factors for 28-day case fatality rate.

CONCLUSIONS

The incidence of cholestatic liver dysfunction is higher than that of hypoxic hepatitis, but it does not increase the 28-day case fatality rate of the ICU patients, suggesting that cholestatic liver dysfunction may be the early adaptation of the liver to critical diseases.

On the Role of Illness Duration and Nutrient Restriction in Cholestatic Alterations that Occur During Critical Illness

Supplemental Digital Content is available in the text

Background and Aims:

Elevated markers of cholestasis are common in response to critical illness, and associated with adverse outcome. The role of illness duration and of nutrient restriction on underlying molecular pathways of such cholestatic responses have not been thoroughly investigated.

Methods:

In a mouse model of surgery- and sepsis-induced critical illness, molecular pathways of cholestasis were investigated up to 7 days. To assess which changes are explained by illness-induced lack of feeding, nutrient-restricted healthy mice were studied and compared with ad libitum fed healthy mice. Furthermore, serum bile acid (BA) concentrations were quantified in 1,114 human patients with either short or long intensive care unit (ICU) stay, matched for type and severity of illness, up to ICU-day-7.

Results:

In critically ill mice, either evoked by surgery or sepsis, circulating and hepatic BA-levels progressively increased with time from day-3 onward, preceded by unsuppressed or upregulated CYP7A1 and CYP27A1 protein expression. From 30 h onward, nuclear farnesoid-X-receptor-retinoid-X-receptor staining was significantly suppressed in both critically ill groups, followed from day-3 onward by decreased gene expression of the apical exporter BA-specific export pump and increased expression of basolateral exporters multidrug resistance-associated protein 3 (MRP3) and MRP4. Nutrient restriction in healthy mice only partly mirrored illness-induced alterations in circulating BA and BA-transporters, without changing nuclear receptors or synthesis markers expression. Also in human critically ill patients, serum BA increased with time in long-stay patients only, similarly for patients with or without sepsis.

Conclusions:

Circulating BA concentrations rose days after onset of sepsis- and surgery-induced, critical illness, only partially explained by lack of feeding, preceded by suppressed nuclear feedback-sensors and ongoing BA synthesis. Expression of transporters suggested ongoing reversed BA-flow toward the blood.

Prevalence and Prognostic Value of Abnormal Liver Test Results in Critically Ill Children and the Impact of Delaying Parenteral Nutrition

OBJECTIVES

In the Early versus Late Parenteral Nutrition in the Pediatric ICU randomized controlled trial, delaying parenteral nutrition to beyond day 7 (late parenteral nutrition) was clinically superior to supplemental parenteral nutrition initiated within 24 hours (early parenteral nutrition), but resulted in a higher rise in bilirubin. We aimed to document prevalence and prognostic value of abnormal liver tests in the PICU and the impact hereon of withholding early parenteral nutrition.

DESIGN

Preplanned secondary analysis of the Early versus Late Parenteral Nutrition in the Pediatric ICU randomized controlled trial. Total bilirubin, alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, alkaline phosphatase plasma concentrations were measured systematically in PICU. Liver test analyses were adjusted for baseline characteristics including severity of illness.

SETTING

Three PICUs in Belgium, the Netherlands, and Canada.

PATIENTS

As neonatal jaundice was considered a confounder, only the 1,231 of the 1,440 Early versus Late Parenteral Nutrition in the Pediatric ICU-patients 28 days to 17 years old were included.

INTERVENTIONS

Late parenteral nutrition as compared with early parenteral nutrition.

MEASUREMENTS AND MAIN RESULTS

During the first seven PICU days, the prevalence of cholestasis (> 2 mg/dL [34.2 μmol/L] bilirubin) ranged between 3.8% and 4.9% and of hypoxic hepatitis (≥ 20-fold upper limit of normality for alanine aminotransferase and aspartate aminotransferase) between 0.8% and 2.2%, both unaffected by the use of parenteral nutrition. Throughout the first week in PICU plasma bilirubin concentrations were higher in late parenteral nutrition patients (p < 0.05), but became comparable to early parenteral nutrition patients as soon as parenteral nutrition was started on day 8. Plasma concentrations of gamma-glutamyl transpeptidase, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase were unaffected by parenteral nutrition. High day 1 plasma concentrations of gamma-glutamyl transpeptidase, alanine aminotransferase, and aspartate aminotransferase (p ≤ 0.01), but not alkaline phosphatase, were independent risk factors for PICU mortality. Day 1 plasma bilirubin concentrations displayed a U-shaped association with PICU mortality, with higher mortality associated with bilirubin less than 0.20 mg/dL and greater than 0.76 mg/dL (< 3.42 μmol/L and > 13 μmol/L) (p ≤ 0.01).

CONCLUSIONS

Overt cholestasis and hypoxic hepatitis were rare and unrelated to the nutritional strategy. However, withholding parenteral nutrition up to 1 week in PICU increased plasma bilirubin. A mild elevation of bilirubin on the first PICU day was associated with lower risk of death and may reflect a stress response, rather than true cholestasis.

Risk factors of hepatic function alterations in hospitalized adult patients treated with short-term parenteral nutrition receiving the same lipid composition at the same dose

BACKGROUND

High doses and vegetable origin of lipid emulsions (LE) are prominent factors for liver test (LT) alterations in patients treated with parenteral nutrition (PN). This study aims to determine incidence of LT alterations, and risk factors related to these alterations in patients with short term PN with homogenous LE.

METHODS

Adult non-critically ill hospitalized patients, with normal LTs at the beginning of PN, receiving 0.8 g/kg/day of an olive/soybean LE were included. A paired Student t-test was applied to compare final with initial LT values. LT variation (end vs start of PN) according to type of surgery and infection was studied by means of an analysis of the variance. Univariate and multivariate analyses were constructed to relate the variations of each of the 4 LTs with the adjustment variables.

RESULTS

One hundred eighty one patients (66.57 ± 12.89 years; 72.4% men), 66.8% suffered from cancer. Final LT values increased from initial values for gamma-glutamyltransferase (GGT) 2.69 ± 2.49 μkat/L vs 0.55 ± 0.36 μkat/L, alkaline phosphatase (AP) 1.97 ± 1.49 μkat/L vs 1.04 ± 0.33 μkat/L, and alanine aminotransferase (ALT) 0.57 ± 0.92 μkat/L vs 0.32 ± 0.26 μkat/L. GGT and AP variations were associated with days of PN; GGT, AP and total bilirubin with surgical patients, AP variations with infection, and GGT with cancer. Multivariate analysis: elevation of GGT, AP and ALT was related to infection, days of PN and surgery.

CONCLUSIONS

Factors that increased the risk of LTs elevation during short term PN treatment were duration of PN, surgery, cancer, and infection associated with oxidative stress.

Cholestatic Alterations in the Critically Ill: Some New Light on an Old Problem

Liver dysfunction and jaundice are traditionally viewed as late features of sepsis and other critical illnesses and are associated with a complicated ICU stay. However, study results suggest that cholestatic alterations occur early in the course of critical illnesses, perceived only as minor abnormalities in routinely used biochemical liver tests. Inflammation-induced alterations in the transport of bile acids (BAs) appear to drive BAs and bilirubin toward the systemic circulation. Ongoing BA synthesis with an, at least partial, loss of feedback inhibition further contributes to elevated circulating BAs and bilirubin. To what extent these changes reflect a biochemical epiphenomenon, true illness-induced liver dysfunction, or a beneficial and adaptive response to illness should be investigated further. Because of the lack of specificity of standard laboratory tests, especially in the context of a complex systemic condition such as critical illness, identifying true cholestatic liver dysfunction remains a great challenge. However, high levels of cholestatic markers that are sustained in patients with prolonged critical illness almost always indicate a complicated illness course and should be monitored closely. Preventing cholestatic liver dysfunction comprises minimizing inflammation and hypoxia in the liver and preventing hyperglycemia, avoiding early use of parenteral nutrition, and reducing the administration of avoidable drugs. Future research on the effects of BAs and on modulating underlying drivers of cholestasis induced by critical illness is warranted as this could open perspectives for a targeted diagnostic approach and ultimately for novel therapies to improve outcome.

Nutrition support in hospitalised adults at nutritional risk

BACKGROUND

The prevalence of disease-related malnutrition in Western European hospitals is estimated to be about 30%. There is no consensus whether poor nutritional status causes poorer clinical outcome or if it is merely associated with it. The intention with all forms of nutrition support is to increase uptake of essential nutrients and improve clinical outcome. Previous reviews have shown conflicting results with regard to the effects of nutrition support.

OBJECTIVES

To assess the benefits and harms of nutrition support versus no intervention, treatment as usual, or placebo in hospitalised adults at nutritional risk.

SEARCH METHODS

We searched Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, MEDLINE (Ovid SP), Embase (Ovid SP), LILACS (BIREME), and Science Citation Index Expanded (Web of Science). We also searched the World Health Organization International Clinical Trials Registry Platform (www.who.int/ictrp); ClinicalTrials.gov; Turning Research Into Practice (TRIP); Google Scholar; and BIOSIS, as well as relevant bibliographies of review articles and personal files. All searches are current to February 2016.

SELECTION CRITERIA

We include randomised clinical trials, irrespective of publication type, publication date, and language, comparing nutrition support versus control in hospitalised adults at nutritional risk. We exclude trials assessing non-standard nutrition support.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and the Cochrane Hepato-Biliary Group. We used trial domains to assess the risks of systematic error (bias). We conducted Trial Sequential Analyses to control for the risks of random errors. We considered a P value of 0.025 or less as statistically significant. We used GRADE methodology. Our primary outcomes were all-cause mortality, serious adverse events, and health-related quality of life.

MAIN RESULTS

We included 244 randomised clinical trials with 28,619 participants that met our inclusion criteria. We considered all trials to be at high risk of bias. Two trials accounted for one-third of all included participants. The included participants were heterogenous with regard to disease (20 different medical specialties). The experimental interventions were parenteral nutrition (86 trials); enteral nutrition (tube-feeding) (80 trials); oral nutrition support (55 trials); mixed experimental intervention (12 trials); general nutrition support (9 trials); and fortified food (2 trials). The control interventions were treatment as usual (122 trials); no intervention (107 trials); and placebo (15 trials). In 204/244 trials, the intervention lasted three days or more.We found no evidence of a difference between nutrition support and control for short-term mortality (end of intervention). The absolute risk was 8.3% across the control groups compared with 7.8% (7.1% to 8.5%) in the intervention groups, based on the risk ratio (RR) of 0.94 (95% confidence interval (CI) 0.86 to 1.03, P = 0.16, 21,758 participants, 114 trials, low quality of evidence). We found no evidence of a difference between nutrition support and control for long-term mortality (maximum follow-up). The absolute risk was 13.2% in the control group compared with 12.2% (11.6% to 13%) following nutritional interventions based on a RR of 0.93 (95% CI 0.88 to 0.99, P = 0.03, 23,170 participants, 127 trials, low quality of evidence). Trial Sequential Analysis showed we only had enough information to assess a risk ratio reduction of approximately 10% or more. A risk ratio reduction of 10% or more could be rejected.We found no evidence of a difference between nutrition support and control for short-term serious adverse events. The absolute risk was 9.9% in the control groups versus 9.2% (8.5% to 10%), with nutrition based on the RR of 0.93 (95% CI 0.86 to 1.01, P = 0.07, 22,087 participants, 123 trials, low quality of evidence). At long-term follow-up, the reduction in the risk of serious adverse events was 1.5%, from 15.2% in control groups to 13.8% (12.9% to 14.7%) following nutritional support (RR 0.91, 95% CI 0.85 to 0.97, P = 0.004, 23,413 participants, 137 trials, low quality of evidence). However, the Trial Sequential Analysis showed we only had enough information to assess a risk ratio reduction of approximately 10% or more. A risk ratio reduction of 10% or more could be rejected.Trial Sequential Analysis of enteral nutrition alone showed that enteral nutrition might reduce serious adverse events at maximum follow-up in people with different diseases. We could find no beneficial effect of oral nutrition support or parenteral nutrition support on all-cause mortality and serious adverse events in any subgroup.Only 16 trials assessed health-related quality of life. We performed a meta-analysis of two trials reporting EuroQoL utility score at long-term follow-up and found very low quality of evidence for effects of nutritional support on quality of life (mean difference (MD) -0.01, 95% CI -0.03 to 0.01; 3961 participants, two trials). Trial Sequential Analyses showed that we did not have enough information to confirm or reject clinically relevant intervention effects on quality of life.Nutrition support may increase weight at short-term follow-up (MD 1.32 kg, 95% CI 0.65 to 2.00, 5445 participants, 68 trials, very low quality of evidence).

AUTHORS' CONCLUSIONS

There is low-quality evidence for the effects of nutrition support on mortality and serious adverse events. Based on the results of our review, it does not appear to lead to a risk ratio reduction of approximately 10% or more in either all-cause mortality or serious adverse events at short-term and long-term follow-up.There is very low-quality evidence for an increase in weight with nutrition support at the end of treatment in hospitalised adults determined to be at nutritional risk. The effects of nutrition support on all remaining outcomes are unclear.Despite the clinically heterogenous population and the high risk of bias of all included trials, our analyses showed limited signs of statistical heterogeneity. Further trials may be warranted, assessing enteral nutrition (tube-feeding) for different patient groups. Future trials ought to be conducted with low risks of systematic errors and low risks of random errors, and they also ought to assess health-related quality of life.

Increased mortality in critically ill patients with mild or moderate hyperbilirubinemia

PURPOSE

Increased bilirubin concentrations may be related to outcome, but this has not been well studied. We evaluated the relationship between total serum bilirubin levels and outcome in critically ill patients.

MATERIALS AND METHODS

Data were analyzed from adult critically ill patients included in a 1-day international prevalence study after excluding those with an obvious underlying cause of hyperbilirubinemia.

RESULTS

Serum bilirubin concentrations were >1 mg/dL in 2803 (31%) of 8973 patients, and these patients had higher mortality rates than patients with lower bilirubin concentrations (30% vs 21%, P<.01). For serum bilirubin values of 1.1-6 mg/dL, there was a linear increase in crude mortality (R²=0.96), with the highest hospital mortality (42%) in patients with bilirubin concentrations between 3.7 and 6.0 mg/dL. There was no further increase in the mortality rates for patients with bilirubin concentrations >6 mg/dL. A serum bilirubin concentration >1 mg/dL was an independent risk factor for mortality in multilevel analysis.

CONCLUSIONS

Hyperbilirubinemia without a recognized cause was common and independently associated with increased mortality. There was a linear correlation of mortality with bilirubin concentration for values between 1 and 6 mg/dL but not for higher values.

Early versus Late Parenteral Nutrition in Critically Ill Children

BACKGROUND

Recent trials have questioned the benefit of early parenteral nutrition in adults. The effect of early parenteral nutrition on clinical outcomes in critically ill children is unclear.

METHODS

We conducted a multicenter, randomized, controlled trial involving 1440 critically ill children to investigate whether withholding parenteral nutrition for 1 week (i.e., providing late parenteral nutrition) in the pediatric intensive care unit (ICU) is clinically superior to providing early parenteral nutrition. Fluid loading was similar in the two groups. The two primary end points were new infection acquired during the ICU stay and the adjusted duration of ICU dependency, as assessed by the number of days in the ICU and as time to discharge alive from ICU. For the 723 patients receiving early parenteral nutrition, parenteral nutrition was initiated within 24 hours after ICU admission, whereas for the 717 patients receiving late parenteral nutrition, parenteral nutrition was not provided until the morning of the 8th day in the ICU. In both groups, enteral nutrition was attempted early and intravenous micronutrients were provided.

RESULTS

Although mortality was similar in the two groups, the percentage of patients with a new infection was 10.7% in the group receiving late parenteral nutrition, as compared with 18.5% in the group receiving early parenteral nutrition (adjusted odds ratio, 0.48; 95% confidence interval [CI], 0.35 to 0.66). The mean (±SE) duration of ICU stay was 6.5±0.4 days in the group receiving late parenteral nutrition, as compared with 9.2±0.8 days in the group receiving early parenteral nutrition; there was also a higher likelihood of an earlier live discharge from the ICU at any time in the late-parenteral-nutrition group (adjusted hazard ratio, 1.23; 95% CI, 1.11 to 1.37). Late parenteral nutrition was associated with a shorter duration of mechanical ventilatory support than was early parenteral nutrition (P=0.001), as well as a smaller proportion of patients receiving renal-replacement therapy (P=0.04) and a shorter duration of hospital stay (P=0.001). Late parenteral nutrition was also associated with lower plasma levels of γ-glutamyltransferase and alkaline phosphatase than was early parenteral nutrition (P=0.001 and P=0.04, respectively), as well as higher levels of bilirubin (P=0.004) and C-reactive protein (P=0.006).

CONCLUSIONS

In critically ill children, withholding parenteral nutrition for 1 week in the ICU was clinically superior to providing early parenteral nutrition. (Funded by the Flemish Agency for Innovation through Science and Technology and others; ClinicalTrials.gov number, NCT01536275.).

Evidence for the use of parenteral nutrition in the pediatric intensive care unit

BACKGROUND AND AIMS

During hospitalization in a pediatric intensive care unit (PICU), critically ill children are fed artificially. Administered via the preferred enteral route, caloric targets are often not reached. Hence, parenteral nutrition is given to this patient population. In this review we analyzed the available evidence from randomized controlled trials (RCTs) that supports the use of parenteral nutrition in children during critical illness.

METHODS

A search strategy in Ovid MEDLINE and Ovid EMBASE was created and trial registries were screened to identify the relevant RCTs. Studies were included if they were randomized controlled trials, involved pediatric patients admitted to PICU, and compared different dosing/compositions of parenteral nutrition. Descriptive studies and reviews were excluded.

RESULTS

Of the 584 articles identified by the search strategy, only 114 articles were retained after title screening. Further abstract and full text screening identified 6 small RCTs that compared two dosing/composition strategies of parenteral nutrition. These trials reported differences in surrogate endpoints without an effect on hard clinical endpoints. The RCTs observed improvements in these surrogate endpoints with the use of more calories or when parenteral glutamine or fish oil was added.

CONCLUSIONS

The few RCTs suggest that surrogate endpoints can be affected by providing parenteral nutrition to critically ill children, but the studies were not statistically powered to draw meaningful clinical conclusions. Large RCTs with clinically relevant outcome measures are urgently needed to support the current nutritional guidelines that advise the use of parenteral nutrition in the PICU.

Nutritional support in critical illness and recovery

An adequate nutritional status is crucial for optimum function of cells and organs, and for wound healing. Options for artificial nutrition have greatly expanded in the past few decades, but have concomitantly shown limitations and potential side-effects. Few rigorous randomised controlled trials (RCTs) have investigated enteral or parenteral nutritional support, and evidence-based clinical guidance is largely restricted to the first week of critical illness. In the early stages of critical illness, whether artificial feeding is better than no feeding intervention has been given little attention in existing RCTs. Expected beneficial effects of various forms of early feeding interventions on rates of morbidity or mortality have generally not been supported by results of recent high-quality RCTs. Thus, whether nutritional interventions early in an intensive care unit (ICU) stay improve outcomes remains unclear. Trials assessing feeding interventions that continue after the first week of critical illness and into the post-ICU and post-hospital settings are clearly needed. Although acute morbidity and mortality will remain important safety parameters in such trials, primary outcomes should perhaps, in view of the adjunctive nature of nutritional intervention in critical illness, be focused on physical function and assessed months or even years after patients are discharged from the ICU. This Series paper is based on results of high-quality RCTs and provides new perspectives on nutritional support during critical illness and recovery.