Glutamine dipeptide for parenteral nutrition in abdominal surgery: A meta-analysis of randomized controlled trials

Usefulness of Perioperative Nutritional Therapy with the Glutamine/Arginine/Calcium β-Hydroxy-β-Methylbutyrate Product in Esophageal Cancer Surgery: A Single-Center Retrospective Study

A useful perioperative nutritional therapy for highly invasive esophageal cancer surgical cases needs to be developed. We clarified the usefulness of amino-acid-enriched nutritional therapy using glutamine (Gln)/arginine (Arg)/calcium β-hydroxy-β-methylbutyrate (HMB) products on the short-term postoperative outcomes of minimally invasive esophagectomy for esophageal cancer. Altogether, 114 patients (Gln/Arg/HMB group) received perioperative nutritional therapy with Gln/Arg/HMB products, and we retrospectively investigated the change in nutritional parameters including skeletal muscle mass, occurrence of postoperative complications, and short-term postoperative outcomes in this group. The results were compared between the Gln/Arg/HMB and control groups (79 patients not receiving the Gln/Arg/HMB products). The incidence of all postoperative complications, sputum expectoration disorder, and pleural effusion of grade ≥ III was significantly lower in the Gln/Arg/HMB group (62.0% vs. 38.6%, p = 0.001; 44.3% vs. 28.1%, p = 0.020; 27.8% vs. 13.2%, p = 0.011, respectively). The psoas muscle area and postoperative body weight were significantly higher at 1 month and 1 year after surgery in the Gln/Arg/HMB group than in the control group (93.5% vs. 99.9%, p < 0.001; 92.0% vs. 95.4%, p = 0.006). Perioperative amino-acid-enriched nutritional therapy may improve the short-term postoperative outcomes, nutritional status, and skeletal muscle mass of esophageal cancer surgical patients.

ECCO Topical Review: Roadmap to Optimal Peri-Operative Care in IBD

BACKGROUND AND AIMS

Despite the advances in medical therapies, a significant proportion of patients with inflammatory bowel diseases [IBD] require surgical intervention. This Topical Review aims to offer expert consensus practice recommendations for peri-operative care to optimize outcomes of IBD patients who undergo surgery.

METHODS

A multidisciplinary panel of IBD healthcare providers systematically reviewed aspects relevant to peri-operative care in IBD. Consensus statements were developed using Delphi methodology.

RESULTS

A total of 20 current practice positions were developed following systematic review of the current literature covering use of medication in the peri-operative period, nutritional assessment and intervention, physical and psychological rehabilitation and prehabilitation, and immediate postoperative care.

CONCLUSION

Peri-operative planning and optimization of the patient are imperative to ensure favourable outcomes and reduced morbidity. This Topical Review provides practice recommendations applicable in the peri-operative period in IBD patients undergoing surgery.

[Glutamine as a component of nutritional and metabolic therapy for surgical patients in ICU]

Glutamine is the most abundant amino acid in the human body that is involved in various metabolic processes. The development of hypermetabolic and hypercatabolic syndrome that accompanies critical conditions of ICU patients is associated with a decrease in the concentration of glutamine, especially in the blood plasma and muscles. This process may last for quite a long time and lead to a number of complications up to a fatal outcome. This review was aimed to analyze clinical studies conducted over the past 20 years that demonstrate the effect of intravenous infusion of glutamine dipeptide as part of balanced parenteral nutrition on the perioperative period: the severity of inflammatory response; the state of the intestinal mucosa; the incidence and severity of complications; mortality; the duration of stay in the ICU and hospital in general, etc. The analysis was performed using systematic reviews and meta-analyses based on randomized double-blind, placebo-controlled trials in different countries selected in the main databases (PubMed, EMBASE, Web of Science, The Cochrane Library, etc.). Most of the reports state that the inclusion of glutamine dipeptide in nutritional and metabolic therapy (NMT) in surgical patients reduces the frequency and severity of infectious complications and mortality, reduces the length of stay in ICU and in hospital in general, improves the biochemical parameters that reflect the condition of patients, and reduces the treatment costs. Thus, the conducted systematic reviews and meta-analyses confirm that the use of the parenteral form of glutamine dipeptide (Dipeptiven 20%) as part of balanced standard parenteral nutrition (PN) is a clinically and pharmacoeconomically justified strategy of NMT in surgical ICU patients.

Properties and regulation of Gly-Sar uptake and transport in bovine intestinal epithelial cells

Intestinal absorption of peptides is vital for the overall health and productivity of dairy cows. This study investigated the regulation, uptake and transport of dipeptides in bovine intestinal epithelial cells (BIECs). We also evaluated the effects of time, pH, concentration of the dipeptides, temperature, presence of diethylpyrocarbonate (DEPC)-an inhibitor of PepT1, and other dipeptides (Met-Met, Lys-Lys or Met-Lys), on the uptake and transport of Gly-Sar-FITC, which was a common fluorophore-labelled dipeptide. Under controlled experiments, BIECs were treated with 25 μM LY294002 (a phosphatidylinositol 3-kinase (PI3K) inhibitor) and 25 μM Perifosine (a protein kinase B (AKT) inhibitor). The subsequent expression of PepT1 in the BIECs was assessed by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting. It was found that the uptake and transport of Gly-Sar-FITC were significant high at 37℃ than that at 4℃. The optimal pH for transport and uptake of Gly-Sar-FITC was 6.0-6.5, whereas the two properties decreased significantly in the presence of DEPC, Met-Met, Lys-Lys and Met-Lys (p < 0.05). The apical-to-basolateral transport was also found to be significantly higher than the reverse transport (p < 0.05). PI3K and AKT inhibitors were found to significantly suppress the expression of PepT1, thus impairing uptake and transport of Gly-Sar-FITC. Findings of this study thus suggest that the uptake and transport of Gly-Sar-FITC in BIECs are mediated by PepT1, and the PI3K/AKT signalling pathway regulates the absorption of small peptides.

Immunonutrition for traumatic brain injury in children and adolescents: protocol for a systematic review and meta-analysis

INTRODUCTION

Traumatic brain injury (TBI) is the leading cause of paediatric trauma death and disability worldwide. The 'Guidelines for the Management of Severe Traumatic Brain Injury (Fourth Edition)' recommend that nutritional goals should be achieved within 5-7 days of injury. Immune-enhancing nutrition or immunonutrition, referring to the addition of specialised nutrients, including glutamine, alanine, omega-3 fatty acids and nucleotides, to standard nutrition formulas, may improve surgical outcomes in the perioperative period. However, the role of immune-enhancing nutritional supplements for patients with paediatric TBI remains unclear. We will conduct a systematic review to determine the efficacy and safety of immunonutrition for patients with paediatric TBI and provide evidence for clinical decision-making.

METHODS AND ANALYSIS

Studies reporting immune-enhancing nutrition treatments for patients with paediatric TBI will be included. Outcomes of interest include the length of hospital stay, wound infections, all-cause mortality, non-wound infection, including pneumonia, urinary tract infection and bacteraemia, and the reports adverse events. Duration of follow-up has no restriction. Primary studies consisting of randomised controlled trials (RCTs) and non-RCTs will be eligible for this review, and only studies published in English will be included. We will search the Medline, Embase and Cochrane Library databases from their inception dates to January 2020. We will also search clinicaltrials.gov and the WHO International Clinical Trials Registry Platform for additional information. Two reviewers will independently select studies and extract data. Risk-of-bias will be assessed with tools based on the Cochrane risk-of-bias criteria and Newcastle-Ottawa Quality Assessment Scale. A meta-analysis will be used to pool data when there are sufficient studies with homogeneity. Heterogeneity of the estimates across studies will be assessed; if necessary, a subgroup analysis will be performed to explore the source of heterogeneity. The Grades of Recommendation, Assessment, Development and Evaluation method will be applied to assess the level of evidence obtained from this systematic review.

ETHICS AND DISSEMINATION

The proposed systematic review and meta-analysis will be based on published data, and thus ethical approval is not required. The results of this review will be published.

PROSPERO REGISTRATION NUMBER

CRD42020154814.

Effects of glutamine supplementation on critically ill patients: Focus on efficacy and safety. An overview of systematic reviews

OBJECTIVES

The aim of this overview of systematic reviews was to synthesize, appraise, and present all systematic review (SR) evidence on the clinical efficacy of glutamine administration to severely ill patients.

METHODS

Medline, Scopus, the Cochrane Library, and Prospero were searched up to March 2020. Systematic reviews and meta-analyses of randomized controlled trials published in English, comparing immunomodulating diets-containing exclusively glutamine-with standard diets for critically ill adult patients were selected. Data were collected from each selected systematic review and all available primary studies. The primary outcome was overall mortality; secondary outcomes were rate of infectious complications, hospital and intensive care unit (ICU) length of stay (LOS).

RESULTS

Seventeen SRs were eligible for inclusion. Of the SRs, 16 included meta-analyses with moderate degree of overlap (corrected covered area = 10%). These included 117 randomized controlled trials with 9933 patients. Glutamine supplementation was not associated with overall mortality and ICU LOS. However, it may reduce the rate of infectious complications overall (N = 3666, risk ratio, 0.82; 95% confidence interval [CI], 0.73-0.92; I² = 33%: low quality of evidence). LOS was limited with the supplementation of glutamine (N = 4353 weighted mean difference, -2.90; 95% CI, -3.66 to -2.15; I² = 81%: very low quality of evidence), but this effect was diminished when only studies with low risk for bias were synthesized.

CONCLUSION

Glutamine could demonstrate a beneficial role in critical care patients of diminishing the rate of infectious complications and hospital and ICU LOS. However, future studies with better quality would confirm this finding.

Effects of parenteral glutamine in critically ill surgical patients: a systematic review and meta-analysis

Introduction

Introduction: glutamine (GLN), the most abundant non-essential amino acid in the plasma, tends to be rapidly depleted in cells in situations of metabolic stress. Some studies have demonstrated the benefits of GLN supplementation on mortality, infection, and length of hospital stay. The objective of this review was to analyze whether parenteral supplementation with GLN has any relevant effect in critically ill surgical patients. Methods: based on a systematic database search, randomized clinical trials (RCTs) published since 1985 were included if they had evaluated the effect of parenteral GLN supplementation in critical surgical patients. The statistical analysis was performed using the RevMan 5.3 software. Results: seven RCTs were eligible for the meta-analysis. Parenteral glutamine supplementation was associated with a non-significant 24 % reduction in mortality (RR = 0.76; 95 % CI: 0.50-1.15). Infections were significantly reduced (RR = 0.60; 95 % CI: 0.45-0.80), and length of hospital stay was 4.09 days shorter (95 % CI: -6.71 to -1.46). Conclusion: parenteral GLN usage in critical surgical patients seems to decrease infection and length of hospital stay, but we could not demonstrate a significant reduction in mortality.

[The Metabolic Optimized Fast Track Concept: preoperative preparation for abdominal surgery]

In recent years the protocols of Enhanced Recovery After Surgery (E.R.A.S.) have been introduced into clinical practice and actively used. The goal of E.R.A.S. is to increase recovery, decrease complications and reduce length of stay after surgery through optimization of perioperative management. One of the key elements of E.R.A.S. is Metabolic Optimized Fast Track Concept (MOFA). It is aimed at the reduction of the period of preoperative fasting and at the activation of glucose transport inside the cell. It involves the administration of combined carbohydrate-protein-glutamine drinks which results into decreased insulin resistance in the early postoperative period. The implementation of MOFA within the structure of perioperative nutrition and metabolic support in abdominal surgery may actually be beneficial by reducing postoperative complications, length of hospital stay and mortality rate.

Therapeutic benefits of glutamine: An umbrella review of meta-analyses

Glutamine may be an essential amino acid in patients with catabolic disease, as it has been demonstrated that circulating glutamine levels drop during critical illness and following major surgery; this may result in an increase in secondary infection risk, recovery time and mortality rates. However, there is much discrepancy in the literature with regards to randomized controlled studies, and therefore, the present study is an umbrella review of published meta-analyses, conducted to examine the effectiveness of glutamine's role as a therapeutic agent. A search using PubMed, Cochrane Library and CINAHL from January 1st, 1980 to December 31st, 2016 was conducted using the following strategy: 'Glutamine AND (meta-analysis OR systematic review)' and publications were retrieved, which provided quantitative statistical analysis of pooled treatment effects on the relative risks of infectious complications, mortality and length of stay in hospital. A total of 22 meta-analyses were entered into the current umbrella review. As displayed in Tables I, II and III, these analyses are split into three groups, based on different parameters. Of the 19 meta-analyses investigating the effects of infectious complications, 15 identified statistically significant reductions in complications, with relative risks ranging between 0.42 and 0.93. In addition, 12 of the 18 meta-analyses analyzing the length of hospital stays presented statistically significant reductions in the length of stay, with reductions ranging between 0.19 to 4.73 days. Only 4 of the 15 meta-analyses studying mortality effects identified statistically significant reductions in mortality with relative risks ranging between 0.64 and 1.28. Statistically significant heterogeneity was observed in 16 of 22 meta-analyses, and publication bias was observed in five of 11 meta-analyses. Glutamine supplementation for critically ill or surgical patients through parenteral or enteral routes appears to reduce the rate of hospital acquired infectious complications and shortening of the length of stay in hospital. Furthermore, glutamine supplementation appeared to reduce the rate of in-patient mortality, but the majority of meta-analyses did not reach statistical significance. However, researchers must appreciate the positive results with caution in light of the fact that there exists statistically significant heterogeneity for the majority of meta-analyses, and statistically significant publication bias in almost half.

Efficacy and Safety of Glutamine-supplemented Parenteral Nutrition in Surgical ICU Patients: An American Multicenter Randomized Controlled Trial

OBJECTIVE

To determine whether glutamine (GLN)-supplemented parenteral nutrition (PN) improves clinical outcomes in surgical intensive care unit (SICU) patients.

SUMMARY BACKGROUND DATA

GLN requirements may increase with critical illness. GLN-supplemented PN may improve clinical outcomes in SICU patients.

METHODS

A parallel-group, multicenter, double-blind, randomized, controlled clinical trial in 150 adults after gastrointestinal, vascular, or cardiac surgery requiring PN and SICU care. Patients were without significant renal or hepatic failure or shock at entry. All received isonitrogenous, isocaloric PN [1.5 g/kg/d amino acids (AAs) and energy at 1.3× estimated basal energy expenditure]. Controls (n = 75) received standard GLN-free PN (STD-PN); the GLN group (n = 75) received PN containing alanyl-GLN dipeptide (0.5 g/kg/d), proportionally replacing AA in PN (GLN-PN). Enteral nutrition (EN) was advanced and PN weaned as indicated. Hospital mortality and infections were primary endpoints.

RESULTS

Baseline characteristics, days on study PN and daily macronutrient intakes via PN and EN, were similar between groups. There were 11 hospital deaths (14.7%) in the GLN-PN group and 13 deaths in the STD-PN group (17.3%; difference, -2.6%; 95% confidence interval, -14.6% to 9.3%; P = 0.66). The 6-month cumulative mortality was 31.4% in the GLN-PN group and 29.7% in the STD-PN group (P = 0.88). Incident bloodstream infection rate was 9.6 and 8.4 per 1000 hospital days in the GLN-PN and STD-PN groups, respectively (P = 0.73). Other clinical outcomes and adverse events were similar.

CONCLUSIONS

PN supplemented with GLN dipeptide was safe, but did not alter clinical outcomes among SICU patients.

Peri-operative nutrition

Patients are frequently malnourished or are at risk of malnutrition before surgery. Peri-operative nutritional support can improve their outcomes. This review focuses on new developments in peri-operative nutrition, including: patient preparation and pre-operative fasting; the role of nutritional supplementation; the optimal route and timing of nutrient delivery; and the nutritional management of specific groups including critically ill, obese and elderly patients.

Preoperative Nutrition and Prehabilitation

Enhanced recovery after surgery is the natural evolution of what were previously referred to as fast track programs and seeks to implement a series of interventions to improve and enhance recovery after major surgical procedures. Two important preoperative aspects are nutrition and prehabilitation. Identifying nutritionally deficient patients allows preoperative intervention to optimize their nutritional status. The contribution of cardiopulmonary exercise testing to the evaluation of perioperative risk, subsequent development of a training program, and the use of indices to risk stratify and measure improvement after a training program allow a personalized preoperative program to be developed for each patient.

Perioperative Alanyl-Glutamine-Supplemented Parenteral Nutrition in Chronic Radiation Enteritis Patients With Surgical Intestinal Obstruction: A Prospective, Randomized, Controlled Study

BACKGROUND

A prospective, randomized, controlled study was performed to evaluate the effects of perioperative alanyl-glutamine-supplemented parenteral nutrition (PN) support on the immunologic function, intestinal permeability, and nutrition status of surgical patients with chronic radiation enteritis (CRE)-induced intestinal obstruction.

METHODS

Patients who received 0.4 g/kg/d alanyl-glutamine and isonitrogenous PN were assigned to an alanyl-glutamine-supplemented PN (Gln-PN) group and a control group, respectively. Serum levels of alanine aminotransferase and glutamine, body fat mass (FM), immunologic function, and intestinal permeability were measured before and after surgery.

RESULTS

Serum glutamine levels of the Gln-PN group significantly exceeded that of the control group (P < .001; Gln-PN, baseline 460.7 ± 42.5 vs 523.3 ± 48.6 µmol/L on postoperative day 14 [POD14], P < .001; control, baseline 451.9 ± 44.0 vs 453.8 ± 42.3 µmol/L on POD14, P = .708). Lactulose/mannitol ratios of both groups decreased over time (Gln-PN, baseline 0.129 ± 0.0403 vs 0.024 ± 0.0107 on POD1 4; control, baseline 0.125 ± 0.0378 vs 0.044 ± 0.0126 on POD14, P < .001 in both groups). CD4/CD8-positive T-lymphocyte ratios significantly rose in both groups, with significant intergroup difference (P < .001; Gln-PN, baseline 1.36 ± 0.32 vs 1.82 ± 0.30 on POD14, P < .001; control, baseline 1.37 ± 0.25 vs 1.63 ± 0.31 on POD14, P < .001). In the Gln-PN group, FM increased from 3.68 ± 1.68 kg at baseline to 5.22 ± 1.42 kg on POD14 (P < .001). FM of control group increased from 3.84 ± 1.57 kg at baseline to 5.40 ± 1.54 kg on POD14 (P < .001). However, there were no significant intergroup differences (P = .614).

CONCLUSION

Gln-PN significantly boosted the immune state and decreased the intestinal permeability of CRE patients. However, Gln-PN was not superior to standard PN in improving the nutrition state and intestinal motility of surgical patients with CRE-induced intestinal obstruction.

Antioxidants as a treatment for acute pancreatitis: A meta-analysis

OBJECTIVE

To assess the efficacy of antioxidants in acute (AP) pancreatitis.

METHODS

We searched PubMed, Embase and the Cochrane library for all randomized controlled trials (RCT) involving administration of antioxidants in the therapy of AP until February 2012. AP studies were pooled to analyze the effect of antioxidants on hospital stay, mortality, and complications. Subgroup analyses were performed on the use of the antioxidant glutamine.

RESULTS

In total, eleven RCTs were included. Among patients with AP, antioxidant therapy resulted in a borderline significant reduction in hospital stay (mean difference -1.74; 95%CI -3.56 to 0.08), a significant decrease in complications (RR 0.66; 95%CI 0.46-0.95) and a non-significant decrease in mortality rate (RR 0.66; 95%CI 0.30-1.46). Subgroup analyses showed that glutamine significantly reduced complications (RR 0.51; 95%CI 0.34-0.78) and mortality rate (RR 0.33; 95%CI 0.13-0.85).

CONCLUSION

The present meta-analysis shows a possible benefit of glutamine supplementation in patients with acute pancreatitis. However, large randomized trials are needed to confirm these observations.

Arginine and citrulline and the immune response in sepsis

Arginine, a semi-essential amino acid is an important initiator of the immune response. Arginine serves as a precursor in several metabolic pathways in different organs. In the immune response, arginine metabolism and availability is determined by the nitric oxide synthases and the arginase enzymes, which convert arginine into nitric oxide (NO) and ornithine, respectively. Limitations in arginine availability during inflammatory conditions regulate macrophages and T-lymfocyte activation. Furthermore, over the past years more evidence has been gathered which showed that arginine and citrulline deficiencies may underlie the detrimental outcome of inflammatory conditions, such as sepsis and endotoxemia. Not only does the immune response contribute to the arginine deficiency, also the impaired arginine de novo synthesis in the kidney has a key role in the eventual observed arginine deficiency. The complex interplay between the immune response and the arginine-NO metabolism is further underscored by recent data of our group. In this review we give an overview of physiological arginine and citrulline metabolism and we address the experimental and clinical studies in which the arginine-citrulline NO pathway plays an essential role in the immune response, as initiator and therapeutic target.

Updated cost-effectiveness analysis of supplemental glutamine for parenteral nutrition of intensive-care patients

Background/Objectives:

Intravenous (i.v.) glutamine supplementation of parenteral nutrition (PN) can improve clinical outcomes, reduce mortality and infection rates and shorten the length of hospital and/or intensive care unit (ICU) stays compared with standard PN. This study is a pharmacoeconomic analysis to determine whether i.v. glutamine supplementation of PN remains both a highly favourable and cost-effective option for Italian ICU patients.

Subjects/Methods:

A previously published discrete event simulation model was updated by incorporating the most up-to-date and clinically relevant efficacy data (a clinically realistic subgroup analysis from a published meta-analysis), recent cost data from the Italian health-care system and the latest epidemiology data from a large Italian ICU database (covering 230 Italian ICUs and more than 77 000 patients). Sensitivity analyses were performed to test the robustness of the results.

Results:

Parenteral glutamine supplementation can significantly improve ICU efficiency in Italy, as the additional cost of supplemented treatment is more than completely offset by cost savings in hospital care. Supplementation was more cost-effective (cost-effectiveness ratio (CER)=€35 165 per patient discharged alive) than standard, non-supplemented PN (CER=€40 156 per patient discharged alive), and it resulted in mean cost savings of €4991 per patient discharged alive or €1047 per patient admitted to the hospital. Sensitivity analyses confirmed the robustness of these results.

Conclusions:

Alanyl-glutamine supplementation of PN is a clinically and economically attractive strategy for ICU patients in Italy and may be applicable to selected ICU patient populations in other countries.

Glutamine supplementation for critically ill adults

BACKGROUND

Glutamine is a non-essential amino acid which is abundant in the healthy human body. There are studies reporting that plasma glutamine levels are reduced in patients with critical illness or following major surgery, suggesting that glutamine may be a conditionally essential amino acid in situations of extreme stress. In the past decade, several clinical trials examining the effects of glutamine supplementation in patients with critical illness or receiving surgery have been done, and the systematic review of this clinical evidence has suggested that glutamine supplementation may reduce infection and mortality rates in patients with critical illness. However, two recent large-scale randomized clinical trials did not find any beneficial effects of glutamine supplementation in patients with critical illness.

OBJECTIVES

The objective of this review was to:1. assess the effects of glutamine supplementation in critically ill adults and in adults after major surgery on infection rate, mortality and other clinically relevant outcomes;2. investigate potential heterogeneity across different patient groups and different routes for providing nutrition.

SEARCH METHODS

We searched the Cochrane Anaesthesia Review Group (CARG) Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 5); MEDLINE (1950 to May 2013); EMBASE (1980 to May 2013) and Web of Science (1945 to May 2013).

SELECTION CRITERIA

We included controlled clinical trials with random or quasi-random allocation that examined glutamine supplementation versus no supplementation or placebo in adults with a critical illness or undergoing elective major surgery. We excluded cross-over trials.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the relevant information from each included study using a standardized data extraction form. For infectious complications and mortality and morbidity outcomes we used risk ratio (RR) as the summary measure with the 95% confidence interval (CI). We calculated, where appropriate, the number needed to treat to benefit (NNTB) and the number needed to treat to harm (NNTH). We presented continuous data as the difference between means (MD) with the 95% CI.

MAIN RESULTS

Our search identified 1999 titles, of which 53 trials (57 articles) fulfilled our inclusion criteria. The 53 included studies enrolled a total of 4671 participants with critical illness or undergoing elective major surgery. We analysed seven domains of potential risk of bias. In 10 studies the risk of bias was evaluated as low in all of the domains. Thirty-three trials (2303 patients) provided data on nosocomial infectious complications; pooling of these data suggested that glutamine supplementation reduced the infectious complications rate in adults with critical illness or undergoing elective major surgery (RR 0.79, 95% CI 0.71 to 0.87, P ＜ 0.00001, I² = 8%, moderate quality evidence). Thirty-six studies reported short-term (hospital or less than one month) mortality. The combined rate of mortality from these studies was not statistically different between the groups receiving glutamine supplement and those receiving no supplement (RR 0.89, 95% CI 0.78 to 1.02, P = 0.10, I² = 22%, low quality evidence). Eleven studies reported long-term (more than six months) mortality; meta-analysis of these studies (2277 participants) yielded a RR of 1.00 (95% CI 0.89 to 1.12, P = 0.94, I² = 30%, moderate quality evidence). Subgroup analysis of infectious complications and mortality outcomes did not find any statistically significant differences between the predefined groups. Hospital length of stay was reported in 36 studies. We found that the length of hospital stay was shorter in the intervention group than in the control group (MD -3.46 days, 95% CI -4.61 to -2.32, P < 0.0001, I² = 63%, low quality evidence). Slightly prolonged intensive care unit (ICU) stay was found in the glutamine supplemented group from 22 studies (2285 participants) (MD 0.18 days, 95% CI 0.07 to 0.29, P = 0.002, I² = 11%, moderate quality evidence). Days on mechanical ventilation (14 studies, 1297 participants) was found to be slightly shorter in the intervention group than in the control group (MD - 0.69 days, 95% CI -1.37 to -0.02, P = 0.04, I² = 18%, moderate quality evidence). There was no clear evidence of a difference between the groups for side effects and quality of life, however results were imprecise for serious adverse events and few studies reported on quality of life. Sensitivity analysis including only low risk of bias studies found that glutamine supplementation had beneficial effects in reducing the length of hospital stay (MD -2.9 days, 95% CI -5.3 to -0.5, P = 0.02, I² = 58%, eight studies) while there was no statistically significant difference between the groups for all of the other outcomes.

AUTHORS' CONCLUSIONS

This review found moderate evidence that glutamine supplementation reduced the infection rate and days on mechanical ventilation, and low quality evidence that glutamine supplementation reduced length of hospital stay in critically ill or surgical patients. It seems to have little or no effect on the risk of mortality and length of ICU stay, however. The effects on the risk of serious side effects were imprecise. The strength of evidence in this review was impaired by a high risk of overall bias, suspected publication bias, and moderate to substantial heterogeneity within the included studies.

Parenteral glutamine supplementation in critical illness: a systematic review

Introduction

The potential benefit of parenteral glutamine (GLN) supplementation has been one of the most commonly studied nutritional interventions in the critical care setting. The aim of this systematic review was to incorporate recent trials of traditional parenteral GLN supplementation in critical illness with previously existing data.

Methods

All randomized controlled trials of parenterally administered GLN in critically ill patients conducted from 1997 to 2013 were identified. Studies of enteral GLN only or combined enteral/parenteral GLN were excluded. Methodological quality of studies was scored and data was abstracted by independent reviewers.

Results

A total of 26 studies involving 2,484 patients examining only parenteral GLN supplementation of nutrition support were identified in ICU patients. Parenteral GLN supplementation was associated with a trend towards a reduction of overall mortality (relative risk (RR) 0.88, 95% confidence interval (CI) 0.75, 1.03, P = 0.10) and a significant reduction in hospital mortality (RR 0.68, 95% CI 0.51, 0.90, P = 0.008). In addition, parenteral GLN was associated with a strong trend towards a reduction in infectious complications (RR 0.86, 95% CI 0.73, 1.02, P = 0.09) and ICU length of stay (LOS) (WMD –1.91, (95% CI -4.10, 0.28, P = 0.09) and significant reduction in hospital LOS (WMD -2.56, 95% CI -4.71, -0.42, P = 0.02). In the subset of studies examining patients receiving parenteral nutrition (PN), parenteral GLN supplementation was associated with a trend towards reduced overall mortality (RR 0.84, 95% CI 0.71, 1.01, P = 0.07).

Conclusions

Parenteral GLN supplementation given in conjunction with nutrition support continues to be associated with a significant reduction in hospital mortality and hospital LOS. Parenteral GLN supplementation as a component of nutrition support should continue to be considered to improve outcomes in critically ill patients.

Clinical evidence for pharmaconutrition in major elective surgery

In recent years, standard nutrition preparations have been modified by adding specific nutrients, such as arginine, ω-3 fatty acids, glutamine, and others, which have been shown to upregulate host immune response, modulate inflammatory response, and improve protein synthesis after surgery. Most randomized trials and several meta-analyses have shown that perioperative administration of enteral arginine, ω-3 fatty acids, and nucleotides (immunonutrition) reduced infection rate and length of hospital stay in patients with upper and lower gastrointestinal (GI) cancer. The most pronounced benefits of immunonutrition were found in subgroups of high-risk and malnourished patients. Promising but not conclusive results have been found in non-GI surgery, especially in head and neck surgery and in cardiac surgery, but larger trials are required before recommending immunonutrition as a routine practice. Conflicting results on the real benefit of parenteral glutamine supplementation in patients undergoing elective major surgery have been published. In conclusion, enteral diets supplemented with specific nutrients significantly improved short-term outcome in patients with cancer undergoing elective GI surgery. Future research should investigate a molecular signaling pathway and identify specific mechanisms of action of immune-enhancing substrates.

Enteral glutamine infusion modulates ubiquitination of heat shock proteins, Grp-75 and Apg-2, in the human duodenal mucosa

Glutamine, the most abundant amino acid in the human body, plays several important roles in the intestine. Previous studies showed that glutamine may affect protein expression by regulating ubiquitin-proteasome system. We thus aimed to evaluate the effects of glutamine on ubiquitinated proteins in human duodenal mucosa. Five healthy male volunteers were included and received during 5 h, on two occasions and in a random order, either an enteral infusion of maltodextrins alone (0.25 g kg(-1) h(-1), control), mimicking carbohydrate-fed state, or maltodextrins with glutamine (0.117 g kg(-1) h(-1), glutamine). Endoscopic duodenal biopsies were then taken. Total cellular protein extracts were separated by 2D gel electrophoresis and analyzed by an immunodetection using anti-ubiquitin antibody. Differentially ubiquitinated proteins were then identified by liquid chromatography-electrospray ionization MS/MS. Five proteins were differentially ubiquitinated between control and glutamine conditions. Among these proteins, we identified two chaperone proteins, Grp75 and hsp74. Grp75 was less ubiquitinated after glutamine infusion compared with control. In contrast, hsp74, also called Apg-2, was more ubiquitinated after glutamine. In conclusion, we provide evidence that glutamine may regulate ubiquitination processes of specific proteins, i.e., Grp75 and Apg-2. Grp75 has protective and anti-inflammatory properties, while Apg-2 indirectly regulates stress-induced cell survival and proliferation through interaction with ZO-1. Further studies should confirm these results in stress conditions.

Ingestion of glutamine and maltodextrin two hours preoperatively improves insulin sensitivity after surgery: a randomized, double blind, controlled trial

OBJECTIVE

To investigate whether the abbreviation of preoperative fasting with a drink containing glutamine and dextrinomaltose improves organic response to surgical trauma.

METHODS

Thirty-six female patients adult (18-62 years) candidates for elective laparoscopic cholecystectomy were randomly divided into three groups: conventional fasting (fasting group), and two groups receiving two different diets, eight hours (400ml) and two hours before induction of anesthesia (200ml): carbohydrate (CHO) group (12.5% dextrinomaltose) and the glutamine (GLN) group (12.5% dextrinomaltose and 40 and 10g of glutamine, respectively). Blood samples were collected pre and postoperatively.

RESULTS

Twenty-eight patients completed the study. No pulmonary complication occurred. Gastric residual volume was similar between groups (p = 0.95). Postoperatively, all patients from the fasting group had abnormal glucose (> 110mg/dl), this abnormality being of 50% when compared to the CHO group (p = 0.14), and of 22.2% when compared to the GLN group (p = 0.01). All patients who had the fasting period shortened (CHO + GLN) had normal postoperative insulin, contrasting with 66.7% in the fasted group (p = 0.02). The abnormal sensitivity to insulin postoperatively rose from 32.1% to 46.4% of cases (p = 0.24), and it occurred in only 11.1% of patients in GLN group when compared to 55.5% in the fasting group (p = 0.02).

CONCLUSION

the abbreviation of preoperative fasting for two hours with dextrinomaltose and glutamine improves insulin sensitivity in patients undergoing elective laparoscopic cholecystectomy.

Glutamine supplementation in acute pancreatitis: a meta-analysis of randomized controlled trials

BACKGROUND

There is emerging evidence that glutamine supplementation should be considered in patients with acute and critical illness associated with a catabolic response. There are reports of glutamine supplementation in acute pancreatitis but the results of these studies are conflicting. The aim of this study was to systematically review the randomised controlled trials (RCT) of glutamine in patients with acute pancreatitis.

METHODS

The Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, SCOPUS and 3 major Chinese databases were searched. The outcomes studied were mortality, total infectious complications, and length of hospital stay. A random effects model was used for meta-analysis of the outcomes in the included trials. A number of pre-specified subgroup analyses were also conducted. The summary estimates were reported as risk ratio (RR) for categorical variables and mean difference (MD) for continuous variables together with the corresponding 95% confidence interval.

RESULTS

Twelve RCT that enrolled 505 patients with acute pancreatitis were included in the final analysis. Overall, glutamine supplementation resulted in a significantly reduced risk of mortality (RR 0.30; 95% CI, 0.15 to 0.60; P < 0.001) and total infectious complications (RR 0.58; 95% CI, 0.39 to 0.87; P = 0.009) but not length of hospital stay (MD -1.35; 95% CI, -3.25 to 0.56, P = 0.17). In the subgroup analyses, only patients who received parenteral nutrition and those who received glutamine in combination with other immunonutrients demonstrated a statistically significant benefit in terms of all the studied outcomes.

CONCLUSIONS

This meta-analysis demonstrates a clear advantage for glutamine supplementation in patients with acute pancreatitis who receive total parenteral nutrition. Patients with acute pancreatitis who receive enteral nutrition do not require glutamine supplementation. Further studies are warranted to determine whether patients who receive combined enteral and parenteral nutrition need glutamine supplementation.

Effects of nitric oxide synthase inhibition on glutamine action in a bacterial translocation model

Glutamine may be a precursor for NO synthesis, which may play a crucial role in bacterial translocation (BT). The goal of the present study was to investigate the potential effects of glutamine on BT and the immunological response in an experimental model of NO synthase inhibition by NG-nitro-L-arginine methyl ester (l-NAME). Mice were randomly assigned to four groups: sham; intestinal obstruction (IO); IO+500 mg/kg per d glutamine (GLN); IO+GLN plus 10 mg/kg per d l-NAME (GLN/LN). The groups were pretreated for 7 d. BT was induced by ileal ligation and was assessed 18 h later by measuring the radioactivity of 99mTc-Escherichiacoli in the blood and organs. Mucosal damage was determined using a histological analysis. Intestinal permeability (IP) was assessed by measuring the levels of 99mTc-diethylenetriaminepentaacetic acid in the blood at 4, 8 and 18 h after surgery. IgA and cytokine concentrations were determined by ELISA in the intestinal fluid and plasma, respectively. BT was increased in the GLN/LN and IO groups than in the GLN and sham groups. IP and intestinal mucosa structure of the sham, GLN and GLN/LN groups were similar. The GLN group had the highest levels of interferon-γ, while IL-10 and secretory IgA levels were higher than those of the IO group but similar to those of the GLN/LN group. The present results suggest that effects of the glutamine pathway on BT were mediated by NO. The latter also interferes with the pro-inflammatory systemic immunological response. On the other hand, IP integrity preserved by the use of glutamine is independent of NO.

Enteral and parenteral nutrition in the perioperative period: state of the art

Nutritional support of surgical and critically ill patients has undergone significant advances since 1936 when Studley demonstrated a direct relationship between pre-operative weight loss and operative mortality. The advent of total parenteral nutrition followed by the extraordinary progress in parenteral and enteral feedings, in addition to the increased knowledge of cellular biology and biochemistry, have allowed clinicians to treat malnutrition and improve surgical patient’s outcomes. We reviewed the literature for the current status of perioperative nutrition comparing parenteral nutrition with enteral nutrition. In a surgical patient with established malnutrition, nutritional support should begin at least 7–10 days prior to surgery. Those patients in whom eating is not anticipated beyond the first five days following surgery should receive the benefits of early enteral or parenteral feeding depending on whether the gut can be used. Compared to parenteral nutrition, enteral nutrition is associated with fewer complications, a decrease in the length of hospital stay, and a favorable cost-benefit analysis. In addition, many patients may benefit from newer enteral formulations such as Immunonutrition as well as disease-specific formulations.

A systematic literature review and meta-analysis of randomized clinical trials of parenteral glutamine supplementation

BACKGROUND & AIMS

Glutamine supplementation has been associated with reduced mortality, infections and hospital length of stay in critically ill patients and patients undergoing major surgery. We carried out a meta-analysis to examine randomized clinical trial (RCT)-based evidence of these effects.

METHODS

Based on a systematic database search, RCTs published since 1990 were included if they evaluated the effect of parenteral glutamine supplementation against a background of parenteral nutrition. Enteral (tube) feeding in a proportion of patients was allowable. Information on RCT methodology, quality and outcomes was extracted. Random effects meta-analysis followed the DerSimonian-Laird approach.

RESULTS

Forty RCTs were eligible for meta-analysis. Parenteral glutamine supplementation was associated with a non-significant 11% reduction in short-term mortality (RR = 0.89; 95% CI, 0.77-1.04). Infections were significantly reduced (RR = 0.83; 95% CI, 0.72-0.95) and length of stay was 2.35 days shorter (95% CI, -3.68 to -1.02) in the glutamine arms. Meta-analysis results were strongly influenced by one recent trial. An element of publication bias could not be excluded.

CONCLUSION

Parenteral glutamine supplementation in severely ill patients may reduce infections, length of stay and mortality, but substantial uncertainty remains. Unlike previous meta-analyses, we could not demonstrate a significant reduction in mortality.

Effects of dietary glutamine supplementation on the body composition and protein status of early-weaned mice inoculated with Mycobacterium bovis Bacillus Calmette-Guerin

Glutamine, one of the most abundant amino acids found in maternal milk, favors protein anabolism. Early-weaned babies are deprived of this source of glutamine, in a period during which endogenous biosynthesis may be insufficient for tissue needs in states of metabolic stress, mainly during infections. The objective of this study was to verify the effects of dietary glutamine supplementation on the body composition and visceral protein status of early-weaned mice inoculated with Mycobacterium bovis Bacillus Calmette-Guérin (BCG). Mice were weaned early on their 14th day of life and seperated into two groups, one of which was fed a glutamine-free diet (n = 16) and the other a glutamine-supplemented diet (40 g/kg diet) (n = 16). At 21 days of age, some mice were intraperitoneally injected with BCG. Euthanasia was performed at the 28th day of age. BCG inoculation significantly reduced body weight (P < 0.001), lean mass (P = 0.002), water (P = 0.006), protein (P = 0.007) and lipid content (P = 0.001) in the carcass. Dietary glutamine supplementation resulted in a significant increase in serum IGF-1 (P = 0.019) and albumin (P = 0.025) concentration, muscle protein concentration (P = 0.035) and lipid content (P = 0.002) in the carcass. In conclusion, dietary glutamine supplementation had a positive influence on visceral protein status but did not affect body composition in early-weaned mice inoculated with BCG.

Perioperative nutritional management in digestive tract surgery

PURPOSE OF REVIEW

This article reviews the recent research on perioperative nutrition in digestive tract surgery in the light of modern perioperative care principles, that is, enhanced recovery after surgery (ERAS). Four major directions of research emerge: detecting malnutrition, perioperative hyperglycemia/insulin resistance, enteral/parenteral nutrition and immunonutrition.

RECENT FINDINGS

For preoperative nutritional screening/assessment, current data cannot single out superiority for SGA questionnaire, nutritional risk score, Reilly's nutritional risk score or nutritional risk index in the ability to predict nutrition-related complications. The use of ERAS elements to reduce surgical stress and preclude postoperative insulin resistance has recently been clearly linked to reductions in adverse outcomes. There are specific situations in which enteral nutrition is contraindicated and criterias for preoperative and postoperative parenteral nutrition in undernourished patients are defined in guidelines recently available. Several controlled randomized studies and systematic reviews indicate that immune nutrition formulas reduce both morbidity and length of stay after major abdominal surgery.

SUMMARY

To reduce surgical stress, insulin resistance, unnecessary protein losses and postoperative complications, the use of an ERAS protocol is important. Current data shows that the use of perioperative immunonutrition diets for major abdominal surgery is beneficial. Further research on nutritional assessment tools to predict who is at risk for postoperative complications is needed.

The Inflammatory Modulation Effect of Glutamine-Enriched Total Parenteral Nutrition in Postoperative Gastrointestinal Cancer Patients

The objective of this study is to explore the inflammatory modulation effect of glutamine-enriched total parenteral nutrition (TPN) by investigating the alterations of inflammation-related cytokines in gastrointestinal (GI) cancer patients postoperatively. Fifty GI cancer patients received postoperative 7 days of isocaloric and isonitrogenous TPN after operation. They were randomly divided to receive either glutamine-enriched TPN or standard TPN. The inflammation-related cytokines including interleukin-6, interleukin-10, and tumor necrosis factor-α were also determined. Records of nutritional assessments, inflammatory status, and postoperative complications were compared between the two groups. Of 50 enrolled patients, 25 patients were classified as the intervention group, and the control group also comprised 25 patients. The differences of gender, age, primary GI malignancies, and hematological and biochemical data between the two compared groups were not statistically significant (all P > 0.05). Compared with standard TPN, a higher serum prealbumin level and better nitrogen balance were observed in glutamine-enriched TPN ( P = 0.039 and 0.048 respectively). A significantly lower serum interleukin-6 level was found in comparing glutamine-enriched with standard TPN ( P = 0.01), but not in interleukin-10 ( P = 0.374) and tumor necrosis factor-α levels ( P = 0.653). Moreover, a significant lower serum C-reactive protein level was detected in glutamine-enriched TPN compared with standard TPN ( P = 0.013). Indeed, four cases of postoperative infectious complications were noted in the control group, but no postoperative infectious complications were observed in the interventional group ( P = 0.037). Our present study shows that glutamine-enriched TPN may be beneficial in improving the inflammatory status and decreasing the infectious morbidity in postoperative GI cancer patients.

Effects of glutamine and curcumin on bacterial translocation in jaundiced rats

AIM: To investigate the effect of curcumin on bacterial translocation and oxidative damage in an obstructive jaundice model and compare the results to glutamine, an agent known to be effective and clinically used.

METHODS: Twenty-four female Wistar-Albino rats, weighing 200-250 g, were randomly divided into three groups (8 in each group). After ligation of the common bile duct in all animals, Group I received oral normal saline, Group II received oral glutamine and Group III received oral curcumin for seven days. Blood samples via cardiac puncture, tissue samples (terminal ileum, liver and mesenteric lymph node) and peritoneal fluid were obtained from the animals at the time of death to investigate bacterial translocation and oxidative damage.

RESULTS: We observed that both glutamine and curcumin reduced bacterial translocation in blood, hepatocellular damage, plasma cytokine levels, oxidative tissue damage and apoptosis significantly compared to the control group. Additionally, glutamine showed protective effects on ileal epithelium and reduced villus atrophy.

CONCLUSION: On the basis of these findings, both curcumin and glutamine are thought to be effective in preventing or reducing bacterial translocation and oxidative damage in obstructive jaundice.

The effect of diet on protein concentration, hypopharyngeal gland development and virus load in worker honey bees (Apis mellifera L.)

Elucidating the mechanisms by which honey bees process pollen vs. protein supplements are important in the generation of artificial diets needed to sustain managed honeybees. We measured the effects of diet on protein concentration, hypopharyngeal gland development and virus titers in worker honey bees fed either pollen, a protein supplement (MegaBee), or a protein-free diet of sugar syrup. Workers consumed more pollen than protein supplement, but protein amounts and size of hypopharyngeal gland acini did not differ between the two feeding treatments. Bees fed sugar syrup alone had lower protein concentrations and smaller hypopharyngeal glands compared with the other feeding treatments especially as the bees aged. Deformed wing virus was detected in workers at the start of a trial. The virus concentrations increased as bees aged and were highest in those fed sugar syrup and lowest in bees fed pollen. Overall results suggest a connection between diet, protein levels and immune response and indicate that colony losses might be reduced by alleviating protein stress through supplemental feeding.

Understanding the mechanisms of glutamine action in critically ill patients

Glutamine (Gln) is an important energy source and has been used as a supplementary energy substrate. Furthermore, Gln is an essential component for numerous metabolic functions, including acid-base homeostasis, gluconeogenesis, nitrogen transport and synthesis of proteins and nucleic acids. Therefore, glutamine plays a significant role in cell homeostasis and organ metabolism. This article aims to review the mechanisms of glutamine action during severe illnesses. In critically ill patients, the increase in mortality was associated with a decreased plasma Gln concentration. During catabolic stress, Gln consumption rate exceeds the supply, and both plasma and skeletal muscle pools of free Gln are severely reduced. The dose and route of Gln administration clearly influence its effectiveness: high-dose parenteral appears to be more beneficial than low-dose enteral administration. Experimental studies reported that Gln may protect cells, tissues, and whole organisms from stress and injury through the following mechanisms: attenuation of NF (nuclear factor)-kB activation, a balance between pro- and anti-inflammatory cytokines, reduction in neutrophil accumulation, improvement in intestinal integrity and immune cell function, and enhanced of heat shock protein expression. In conclusion, high-doses of parenteral Gln (>0.50 g/kg/day) demonstrate a greater potential to benefit in critically ill patients, although Gln pathophysiological mechanisms requires elucidation.

Effect of glutamine in patients with esophagus resection

Glutamine is the most abundant amino-acid in the extra- and intracellular compartments of the human body, which accounts for over 50% of its free amino-acid content. Utilization of glutamine peptides is explicitly useful, resulting in a decrease in the number of postoperative infectious complications, period of hospitalization, and therapeutic costs. This article aims to study the effects of glutamine on systemic inflammatory response, morbidity, and mortality after esophagectomy. A prospective, randomized, double-blind, and controlled trial was used. Following sealed-envelope block randomization, the patients were divided into two groups. Members of the glutamine group (group G) received glutamine (Dipeptiven, Fresenius) as continuous infusion for 6 hours at 0.5 g/kg for 3 days prior to, and 7 days following surgery; while patients of the control group were given placebo. We examined 30 patients in group G, and 25 patients as controls. In both patient groups, the levels of total protein, albumin, pre-albumin, retinol binding protein, transferrin, transferring-saturation, C-reactive protein, procalcitonin, lymphocte, Interleukin-6, Interleukin-8, tumor necrosis factor alpha, and serum lactate were determined prior to surgery (t(0)), directly after surgery (t(u)), following surgery on day 1 (t(1)), day 2 (t(2)), and day 7 (t(7)). For statistical analysis Mann-Whitney U test and chi-square test were used. There was no significant difference between the two groups regarding age, male/female ratio, and SAPS II scores. Intensive care unit morbidity and mortality was similar in both groups (group G: 24 survivors/6 nonsurvivors;

CONTROL

17 survivors/8 nonsurvivors; P= 0.607). Daily Multiple Organ Dysfunction Score did not differ significantly between the two groups. The observed inflammatory markers followed the pattern we described without significant difference. Based on our study, the glutamine supplementation that we used had no influence on morbidity, mortality, or postoperative inflammatory response after esophagectomy.

Advancing from immunonutrition to a pharmaconutrition: a gigantic challenge

PURPOSE OF REVIEW

This review presents some difficulties encountered to develop and translate immunonutrition into clinical practice, and suggests moving forward to a pharmaconutrition approach.

RECENT FINDINGS

Immunonutrition suffers from inconclusive and contradictory data due to the design of many of experiments and clinical studies conducted so far. The concept of a single immunonutrient formula applicable to various types of patients has also contributed to leave the medical world in a state of uncertainty. We propose to move forward to the concept of pharmaconutrition where a disease-dedicated nutrition therapy is developed following a rigorous step-by-step procedure. Nutrients are selected according to their pharmacological properties and after an in-depth evaluation of their biological interactions when mixed together. The optimum administration schedule (i.e. dose, route, timing and duration) of the new formulae is then determined in well conducted projective clinical trials where it is administered apart from the standard nutrition to ensure full delivery of the expected doses.

SUMMARY

This review suggests moving forward to a pharmaconutrition approach where a rigorous step-by-step procedure would allow overcoming of the difficulties encountered to translate immunonutrition into clinical practice.

ESPEN Guidelines on Parenteral Nutrition: surgery

In modern surgical practice it is advisable to manage patients within an enhanced recovery protocol and thereby have them eating normal food within 1-3 days. Consequently, there is little room for routine perioperative artificial nutrition. Only a minority of patients may benefit from such therapy. These are predominantly patients who are at risk of developing complications after surgery. The main goals of perioperative nutritional support are to minimize negative protein balance by avoiding starvation, with the purpose of maintaining muscle, immune, and cognitive function and to enhance postoperative recovery. Several studies have demonstrated that 7-10 days of preoperative parenteral nutrition improves postoperative outcome in patients with severe undernutrition who cannot be adequately orally or enterally fed. Conversely, its use in well-nourished or mildly undernourished patients is associated with either no benefit or with increased morbidity. Postoperative parenteral nutrition is recommended in patients who cannot meet their caloric requirements within 7-10 days orally or enterally. In patients who require postoperative artificial nutrition, enteral feeding or a combination of enteral and supplementary parenteral feeding is the first choice. The main consideration when administering fat and carbohydrates in parenteral nutrition is not to overfeed the patient. The commonly used formula of 25 kcal/kg ideal body weight furnishes an approximate estimate of daily energy expenditure and requirements. Under conditions of severe stress requirements may approach 30 kcal/kg ideal body weights. In those patients who are unable to be fed via the enteral route after surgery, and in whom total or near total parenteral nutrition is required, a full range of vitamins and trace elements should be supplemented on a daily basis.

Parenteral nutrition and urban legends

PURPOSE OF REVIEW

To assess the recent literature regarding parenteral nutrition to identify publications that have purported to support various beliefs about the utility of parenteral nutrition, and then to critically evaluate the data presented in those (as well as prior) publications.

RECENT FINDINGS

Artificial nutrition improves nutritional markers but not clinical outcomes, suggesting that malnutrition is not causatively associated with a poor outcome. There are no convincing data that parenteral nutrition is beneficial in severely malnourished surgical patients. Glutamine supplementation of parenteral nutrition solutions may reduce the infectious complication rate, but it is unknown if glutamine-supplemented parenteral nutrition is better than no parenteral nutrition. Most, but not all, systematic reviews have demonstrated that enteral nutrition produces fewer problems than parenteral nutrition; no data suggest that either modality is better than doing no artificial nutrition. Randomized trials have not uniformly been able to demonstrate that parenteral nutrition is efficacious in acute pancreatitis. There is some, but not convincing, data that a regimen of glutamine, growth hormone, and a specialized diet will reduce the need for parenteral nutrition in patients with short bowel syndrome.

SUMMARY

It is important for clinicians to be able to critically evaluate the medical literature.

Impact of alanyl-glutamine dipeptide on severe acute pancreatitis in early stage

AIM: To evaluate the therapeutic effect of alanyl-glutamine dipeptide (AGD) in the treatment of severe acute pancreatitis (SAP) in early and advanced stage.

METHODS: Eighty patients with SAP were randomized and received 100 mL/d of 20% AGD intravenously for 10 d starting either on the day of (early treatment group) or 5 d after (late treatment group) admission. Groups had similar demographics, underlying diseases, Ranson score, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and Balthazar’s computed tomography (CT) score at the beginning of the study and underwent similar other medical and nutritional management.

RESULTS: The duration of acute respiratory distress syndrome (2.7 ± 3.3 d vs 12.7 ± 21.0 d, P < 0.01), renal failure (1.3 ± 0.5 d vs 5.3 ± 7.3 d, P < 0.01), acute hepatitis (3.2 ± 2.3 d vs 7.0 ± 7.1 d, P < 0.01), shock (1.7 ± 0.4 d vs 4.8 ± 3.1 d, P < 0.05), encephalopathy (2.3 ± 1.9 d vs 9.5 ± 11.0 d, P < 0.01) and enteroparalysis (2.2 ± 1.4 d vs 3.5 ± 2.2 d, P < 0.01) and hospital stay (28.8 ± 9.4 d vs 45.2 ± 27.1 d, P < 0.01) were shorter in the early treatment group than in the late treatment group. The 15-d APACHE II score was lower in the early treatment group than in the late treatment group (5.0 ± 2.4 vs 8.6 ± 3.6, P < 0.01). The infection rate (7.9% vs 26.3%, P < 0.05), operation rate (13.2% vs 34.2%, P < 0.05) and mortality (5.3% vs 21.1%, P < 0.05) in the early treatment group were lower than in the late treatment group.

CONCLUSION: Early treatment with AGD achieved a better clinical outcome in SAP patients.

Practicalities of nutrition support in the intensive care unit

PURPOSE OF REVIEW

Nutrition support improves clinical outcomes in the critically ill and our understanding of its effects has advanced significantly over the last few years. Three recently published evidence-based guidelines have made generally consistent and thorough recommendations to assist clinicians in providing nutrition support. This review will focus on various aspects of these recommendations, concentrating on the practicalities of nutrition support in the intensive care unit, such as its optimal mode and composition.

RECENT FINDINGS

Enteral nutrition is preferred to parenteral nutrition unless there is a major gut condition which will delay commencement of enteral nutrition. Nasogastric feeding should begin within 24 h, but if intolerance develops, small bowel feeding or pro-motility drugs (erythromycin or metoclopramide) should be attempted before resorting to supplementary parenteral nutrition. Enteral nutrition should not routinely be supplemented with arginine or glutamine, but it should contain a package of eicosapentaenoic acid, gamma-linolenic acid and antioxidants if the patient has acute lung injury or sepsis. Parenteral nutrition should be glutamine supplemented and the prescription should be limited in energy to avoid hyperglycemia. Whether using enteral nutrition or parenteral nutrition, most patients should receive intravenous selenium, and may also need zinc and copper supplementation.

SUMMARY

Intensive care unit patients should have nutrition support based on recent evidence-based guidelines with a preference for nasogastric feeding. If intolerance occurs, pro-motility drugs and small bowel feeding should be attempted. Clinicians should also consider carefully the composition of the nutrition support regimen with regard to lipid content (especially eicosapentaenoic acid and gamma-linolenic acid), antioxidants, glutamine and other micronutrients.