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

Synthesis of glutamine-based green emitting carbon quantum dots as a fluorescent nanoprobe for the determination of iron (Fe3+) in Solanum tuberrosum (potato)

Herein, we reported the use of N-doped green-emitting carbon quantum dots (N-CQDs) as a fluorescent probe for determining of Fe³⁺ ions in Solanum tuberosum for the first time. The N-CQDs were synthesised through an efficient, one-step, and safe hydrothermal technique using citric acid as the carbon source and glutamine as a novel nitrogen source. The temporal evolution of the optical properties was investigated by varying the synthetic conditions with respect to temperature (160 °C, 180 °C, 200 °C, 220 °C and 240 °C) and citric acid: glutamine precursor ratio (1:1, 1:1.5, l.2,1:3 and 1:4). The N-CQDs was characterised using Fourier-Transform Infra-red Spectroscopy (FTIR) High-resolution transmission electron microscope (HRTEM), ultraviolet-visible spectroscopy (UV-vis) and X-Ray diffraction analysis (XRD) while its stability was evaluated in different media; NaCl, Roswell Park Memorial Institute (RPMI) and Phosphate Buffered Saline (PBS), and at different pHs. The N-CQDs displayed green (525 nm) emission and were spherical with an average particle diameter of 3.41 ± 0.76 nm. The FTIR indicated carboxylic, amino, and hydroxyl functional groups. The as-synthesised N-CQDs were stable in NaCl (up to 1 M), RPMI, and PBS without any significant change in its fluorescent intensity. The pH evaluation showed pHs 6 and 7 as the optimum pHs, while the fluorometric analysis showed selectivity towards Fe ³⁺ in the presence and absence of interfering ions. The detection limit of 1.05 μM was calculated, and the photoluminescence mechanism revealed static quenching. The as-synthesised N-CQDs was used as a fluorescent nanoprobe to determine the amount of Fe³⁺ in Solanum tuberosum (Potatoes) tubers. The result showed a high level of accuracy (92.13-96.20%) when compared with an established standard analytical procedure with excellent recoveries of 99.23-103.9%. We believe the as-synthesised N-CQDs can be utilised as a reliable and fast fluorescence nanoprobe for the determining of Fe³⁺ ions.

Metabolic Support in Acute Respiratory Distress Syndrome: A Narrative Review

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

Perioperative nutrition for gastrointestinal surgery: On the cutting edge

Evidence on perioperative nutrition interventions in gastrointestinal surgery is rapidly evolving. We conducted a narrative review of various aspects of nutrition support, including formula choice and route of administration, as well as duration and timing of nutrition support therapy. Studies have demonstrated that nutrition support is associated with improved clinical outcomes in malnourished patients and those at nutrition risk, emphasizing the importance of nutrition assessment, for which several validated nutrition risk assessment tools exist. The assessment of serum albumin levels has fallen out of favor, as it is an unreliable marker of nutrition status, whereas imaging evidence of sarcopenia has prognostic value and may emerge as a standard component of nutrition assessment. Preoperatively, evidence supports limiting fasting to reduce insulin resistance and improve oral tolerance. Benefits to preoperative carbohydrate loading remain unclear, whereas literature suggests preoperative parenteral nutrition (PN) may reduce postoperative complications in high-risk patients with malnutrition or sarcopenia. Postoperatively, early oral feeding is safe with benefits in time to return of bowel function and reduced hospital stay. There is a signal for potential benefit to early postoperative PN in critically ill patients, though evidence is sparse. There has also been a recent emergence in randomized studies evaluating the use of ω-3 fatty acids, amino acids, and immunonutrition. Meta-analyses have reported favorable outcomes for these supplements, though individual studies are small and with significant methodological limitations and risk of bias, emphasizing the need for high-quality randomized studies to guide clinical practice.

Parenteral Nutrition Overview

Parenteral nutrition (PN) is a life-saving intervention for patients where oral or enteral nutrition (EN) cannot be achieved or is not acceptable. The essential components of PN are carbohydrates, lipids, amino acids, vitamins, trace elements, electrolytes and water. PN should be provided via a central line because of its hypertonicity. However, peripheral PN (with lower nutrient content and larger volume) can be administered via an appropriate non-central line. There are alternatives for the compounding process also, including hospital pharmacy compounded bags and commercial multichamber bags. PN is a costly therapy and has been associated with complications. Metabolic complications related to macro and micronutrient disturbances, such as hyperglycemia, hypertriglyceridemia, and electrolyte imbalance, may occur at any time during PN therapy, as well as infectious complications, mostly related to venous access. Long-term complications, such as hepatobiliary and bone disease are associated with longer PN therapy and home-PN. To prevent and mitigate potential complications, the optimal monitoring and early management of imbalances is required. PN should be prescribed for malnourished patients or high-risk patients with malnutrition where the feasibility of full EN is in question. Several factors should be considered when providing PN, including timing of initiation, clinical status, and risk of complications.

Postoperative Nutrition Management: Who Needs What?

Background

Early oral feeding after major abdominal surgery has been clearly shown to be safe and not a risk factor for anastomotic dehiscence. Within the Enhanced Recovery after Surgery protocol, it is the nutritional plan A. Nonetheless, one must consider that postoperative protein and energy requirements will often be not covered by oral food intake alone. Because nutritional status has been shown to be a prognostic factor in patients undergoing major abdominal surgery, the preoperative identification of patients at risk may be mandatory. Malnutrition may be underestimated in an overweight society. With special regard to patients with cancer and those with preexisting malnutrition, an accumulating caloric gap may be harmful in the early and late postoperative periods. Furthermore, complications requiring reoperation and intensive care treatment may occur.

Summary

Therefore, a plan B for postoperative nutrition therapy is needed, using preferentially the enteral route. The European Society for Clinical Nutrition and Metabolism recently addressed perioperative nutritional management and the indications for enteral and even parenteral supplementation to achieve caloric requirements in the postoperative course. In the first months after surgery, persisting weight loss is common in patients with upper gastrointestinal resections, even in those with an uncomplicated course. This may delay the initiation of adjuvant chemotherapy, increase toxicity, and worsen long-term outcomes.

Unresolved issues in perioperative nutrition: A narrative review

Surgical patients are at an increased risk of negative outcomes if they are malnourished or at risk of malnutrition preoperatively. Optimisation of nutritional status should be a focus throughout the perioperative continuum to promote improved surgical outcomes. Enhanced Recovery after Surgery (ERAS) protocols are increasingly applied in the surgical setting but are not yet widespread. This narrative review focused on areas of perioperative nutrition that are perceived as controversial or are lacking in agreement. A search for available literature was conducted on 1 March 2022 and relevant high-quality articles published since 2015 were considered for inclusion. Most malnutrition screening tools are not specific to the surgical population except for the Perioperative Nutrition Screen (PONS) although more large-scale initiatives are needed to improve the prevalence of preoperative nutrition screening. Poor muscle health is common in patients with malnutrition and further exacerbates negative health outcomes indicating that prevention, detection and treatment is of high importance in this population. Although a lack of consensus remains for who should receive preoperative nutritional therapy, evidence suggests a positive impact on muscle health. Additionally, postoperative nutritional support benefits surgical outcomes, with some patients requiring enteral and/or parenteral feeding routes and showing benefit from immunonutrition. The importance of nutrition extends beyond the time in hospital and should remain a priority post-discharge. The impact of individual or personalised nutrition based on select patient characteristics remains to be further investigated. Overall, the importance of perioperative nutrition is evident in the literature despite select ongoing areas of contention.

How to Prevent Surgical Site Infection in Vascular Surgery: A Review of the Evidence

BACKGROUND

This review aims to identify and review the current evidence for preventing postoperative surgical site infections in abdominal aortic aneurysm surgery or infrainguinal arterial surgery.

METHODS

Extended literature review of clinical trials that examined the prevention of postoperative surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. Searches were conducted on Ovid MEDLINE (1950 - 13 March 2020) using key terms for vascular surgery, surgical site infections and specific preventative techniques. Articles were included if they discussed a relationship between a preventative technique and surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. The GRADE guidelines were used to assess the quality of evidence.

RESULTS

21 techniques and 81 studies were included. Prophylactic antibiotics and negative pressure wound therapy have a high quality of evidence for the prevention of surgical site infections in abdominal aortic aneurysm or infrainguinal arterial surgery. A moderate quality evidence base was identified for gentamicin containing collagen implant (confined to high surgical site infection risk centers). Currently, there is a low or very low quality of evidence to suggest a reduction in the surgical site infection rate for combination therapy, glycaemic control, Methicillin-resistant Staphylococcus aureus screening and absorbable suture. Evidence suggests no beneficial effect for nutritional supplementation, chlorhexidine bath, hair removal therapy, Staphylococcus aureus nasal eradication, cyanoacrylate microsealant, silver grafts, rifampicin bonded grafts, triclosan coated suture and postoperative wound drains. Endoscopic saphenous vein harvest may reduce surgical site infection rate (very low quality of evidence) but may lower long-term patency. Autologous vein grafts may increase surgical site infections (very low quality of evidence) but may provide better long-term patency rates in above-knee infrainguinal bypass surgery. There was no identified evidence for perioperative normothermia, electrosurgical bipolar vessel sealer or Dermabond and Tegaderm for surgical site infection prevention in vascular surgery.

CONCLUSIONS

Prophylactic antibiotics and postoperative negative pressure wound therapy are effective in the prevention of postoperative surgical site infection in abdominal aortic aneurysm or infrainguinal arterial surgery. There exists a significant risk of bias in the literature for many preventative techniques and further studies are required to investigate the efficacy of gentamicin containing collagen implant, and specific combination therapies.

Glutamine Administration Attenuates Kidney Inflammation in Obese Mice Complicated with Polymicrobial Sepsis

Obesity is a well-known public health issue around the world. Sepsis is a lethal clinical syndrome that causes multiorgan failure. Obesity may aggravate inflammation in septic patients. Glutamine (GLN) is a nutrient with immune regulatory and anti-inflammatory properties. Since sepsis is a common contributing factor for acute kidney injury (AKI), this study investigated the effects of GLN administration on sepsis-induced inflammation and AKI in obese mice. A high-fat diet which consists of 60% of calories from fat was provided for 10 weeks to induce obesity in the mice. Then, the obese mice were subdivided into sepsis with saline (SS) or GLN (SG) groups. Cecal ligation and puncture (CLP) was performed to produce sepsis. The SS group was intravenously injected with saline while the SG group was administered GLN one or two doses after CLP. Obese mice with sepsis were sacrificed at 12, 24, or 48 h post-CLP. Results revealed that sepsis resulted in upregulated high-mobility group box protein-1 pathway-associated gene expression in obese mice. Also, expressions of macrophage/neutrophil infiltration markers and inflammatory cytokines in kidneys were elevated. Obese mice treated with GLN after sepsis reversed the depletion of plasma GLN, reduced production of lipid peroxides, and downregulated macrophage/neutrophil infiltration and the inflammatory-associated pathway whereas tight junction gene expression increased in the kidneys. These findings suggest that intravenously administered GLN to obese mice after sepsis alleviated inflammation and attenuated AKI. This model may have clinical application to obese patients with a risk for infection in abdominal surgery.

Effects of the Glutamine Administration on T Helper Cell Regulation and Inflammatory Response in Obese Mice Complicated with Polymicrobial Sepsis

This study investigated the impacts of GLN on inflammation and T cell dysregulation in obese mice complicated with sepsis. Mice were divided into normal control (NC) and high-fat diet groups. The high-fat diet provided 60% of energy from fat and was administered for 10 weeks to induce obesity. Mice fed with a high-fat diet were then assigned to sham (SH) and sepsis with saline (SS) or GLN (SG) groups. The SH group was subjected to laparotomy, while the sepsis group underwent cecal ligation and puncture (CLP). The SS group was intravenously injected with saline. The SG group was intravenously administered GLN after CLP. Mice were sacrificed at 12, 24, or 48 h post-CLP, respectively. Results demonstrated that in the presence of obesity, sepsis drove CD4+ T cells toward the helper T (Th)2 and Th17 lineages. Also, expressions of inflammatory cytokines and macrophage infiltration markers in adipose tissues and lungs were elevated. Treatment of obese mice with GLN after sepsis reversed Th polarization and downregulated macrophage infiltration and inflammatory cytokine, whereas the tight junction-associated protein expression increased in the lungs. These findings suggest that the intravenous administration of GLN to obese mice after sepsis modulated a more balanced Th cell lineage, alleviated inflammation, and attenuated lung injury.

Perioperative nutrition: Recommendations from the ESPEN expert group

BACKGROUND & AIMS

Malnutrition has been recognized as a major risk factor for adverse postoperative outcomes. The ESPEN Symposium on perioperative nutrition was held in Nottingham, UK, on 14-15 October 2018 and the aims of this document were to highlight the scientific basis for the nutritional and metabolic management of surgical patients.

METHODS

This paper represents the opinion of experts in this multidisciplinary field and those of a patient and caregiver, based on current evidence. It highlights the current state of the art.

RESULTS

Surgical patients may present with varying degrees of malnutrition, sarcopenia, cachexia, obesity and myosteatosis. Preoperative optimization can help improve outcomes. Perioperative fluid therapy should aim at keeping the patient in as near zero fluid and electrolyte balance as possible. Similarly, glycemic control is especially important in those patients with poorly controlled diabetes, with a stepwise increase in the risk of infectious complications and mortality per increasing HbA1c. Immobilization can induce a decline in basal energy expenditure, reduced insulin sensitivity, anabolic resistance to protein nutrition and muscle strength, all of which impair clinical outcomes. There is a role for pharmaconutrition, pre-, pro- and syn-biotics, with the evidence being stronger in those undergoing surgery for gastrointestinal cancer.

CONCLUSIONS

Nutritional assessment of the surgical patient together with the appropriate interventions to restore the energy deficit, avoid weight loss, preserve the gut microbiome and improve functional performance are all necessary components of the nutritional, metabolic and functional conditioning of the surgical patient.

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.

Effectiveness and mechanism study of glutamine on alleviating hypermetabolism in burned rats

OBJECTIVES

This study aimed to explore the effects of glutamine on hypermetabolic reactions in burned rats and its underlying mechanism.

METHODS

Fifty-five Sprague-Dawley rats were randomly divided into three groups, namely, the control (C), burned (B), and burned + glutamine (B + G) groups. Rats in the glutamine treatment group were supplemented with 1 g glutamine per kg body weight. Changes in body weight and resting energy expenditure in all groups were observed daily. Blood glucose and glucose tolerance level were measured on days 1, 3, 7, 10 and 14 after burn injury. On days 7 and 14 after injury, the rats were sacrificed, and the weight and protein content of the skeletal muscle were measured. Moreover, the level of glutamine, inflammatory mediator, nicotinamide adenine dinucleotide phosphate (NADPH), glutathione, and the activity of glutamine metabolic enzymes were measured.

RESULTS

The hypermetabolic reaction after burn injury was significantly inhibited by glutamine administration, and the range of variations in the resting energy expenditure and body weight indicators was narrowed remarkably (P < 0.05 or 0.01), whereas the weight and protein content of the skeletal muscle returned to normal (P < 0.05 or 0.01). Glutamine could increase glutaminase activity in various tissues, promote the utilization of glutamine, and appropriately reduce the degree of organ damage and inflammatory response (P < 0.05 or 0.01). Furthermore, glutamine could promote the synthesis of the reducing substances NADPH and glutathione (P < 0.05 or 0.01).

CONCLUSIONS

Glutamine administration effectively reduces hypermetabolic reactions by promoting NADPH synthesis, inhibiting oxidative stress, and improving glutamine utilization after burn injury.

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.

Antecedent Dietary Glutamine Supplementation Benefits Modulation of Liver Pyroptosis in Mice with Polymicrobial Sepsis

The liver is the main organ responsible for bacterial and endotoxin clearance. Pyroptosis is a form of proinflammatory programmed cell death activated by caspase-1/11 and gasdermin D (GadD). Pyroptosis protects the host against bacterial infection; however, overactive pyroptosis can lead to organ injury. Glutamine (GLN) is a specific amino acid with anti-inflammatory and immunomodulatory properties. This study investigated the effects of GLN pretreatment on liver pyroptosis in a mouse model of polymicrobial sepsis. Mice were assigned to sham, sepsis control (Sepsis-C), and sepsis GLN (Sepsis-G) groups. The sham and Sepsis-C groups were fed the AIN-93G diet. The Sepsis-G group was provided with identical diet components except that part of the casein was replaced by GLN. After feeding the respective diets for 2 weeks, a cecal ligation and puncture (CLP) procedure was performed in the sepsis groups. An antibiotic was administered after CLP. Mice were sacrificed at either 24 or 72 h after CLP. The results showed that sepsis resulted in upregulated liver caspase-1/11 expression. Compared to the Sepsis-C group, the Sepsis-G group had higher liver caspase-11 and NLRP3 gene expressions at 24 h and lower active caspase-1/11 and cleaved GadD protein levels at 72 h after sepsis. Additionally, liver inflammatory cytokine gene expressions had decreased by 72 h post-CLP. The findings suggest that prophylactic administration of GLN initially upregulated liver pyroptosis to eradicate pathogens, yet the process of pyroptosis was suppressed in the late phase of sepsis. This may have beneficially attenuated liver inflammation and injury in an antibiotic-treated septic condition.

The glutamine debate in surgery and critical care

PURPOSE OF REVIEW

Glutamine (GLN) is a versatile amino acid, long believed to have important implications in ICU and surgical patients. An extensive body of data examining GLN supplementation of TPN demonstrated a consistent signal of improved outcomes. However, recently signals of risk have come from two large-scale multicenter trials evaluating GLN (and other nutrients) at high dose and as primary pharmaconutrients, not as supplementation to complete nutrition. These trials indicate a risk of increased mortality when GLN is given to patients in shock, renal failure, and early in acute phase of critical care.

RECENT FINDINGS

Recent literature continues to confirm that low and high admission GLN levels are associated with increased ICU mortality and adverse outcomes. Further, a recent meta-analysis examined trials utilizing GLN-supplemented TPN in stabile ICU patients consistent with current clinical guidelines. This analysis showed GLN supplementation of TPN led to reduced infections, LOS and hospital mortality.

SUMMARY

Three recent meta-analyses have confirmed traditional GLN-supplemented (or 'GLN-Complemented' - providing GLN for completeness of amino acid content) TPN is safe, reduces mortality and improves outcome in surgical and ICU patients. Patients in need of TPN, burns, trauma or malignancies should continue to benefit from supplemental GLN, administered either intravenously at less than 0.35 g/kg/day or enterally at less than 0.5 g/kg/day. Further, a large trial of EN GLN supplementation in burns is ongoing. Thus, when used per guideline recommendations, the GLN story is likely still relevant to ICU outcomes and research.

L-glutamine for sickle cell disease: Knight or pawn?

Oxidative stress is an important contributor to the pathophysiology of sickle cell disease. The pathways involved are complex and interlinked. L-glutamine is an amino acid with myriad roles in the body, including the synthesis of antioxidants, such as reduced glutathione and the cofactors NAD(H) and NADP(H), as well as nitric oxide—so it has therapeutic potential as an antioxidant. However, the relative impact of L-glutamine on the redox environment in red blood cells in sickle cell disease is not fully understood, and there are few therapeutic trials in sickle cell disease. Following the FDA approval of L-glutamine for sickle cell disease, more research is still needed to understand its clinical effects and role in therapy.

Role of heat shock protein and cytokine expression as markers of clinical outcomes with glutamine-supplemented parenteral nutrition in surgical ICU patients

BACKGROUND

Nutrients, such as glutamine (GLN), have been shown to effect levels of a family of protective proteins termed heat shock proteins (HSPs) in experimental and clinical critical illness. HSPs are believed to serve as extracellular inflammatory messengers and intracellular cytoprotective molecules. Extracellular HSP70 (eHSP70) has been termed a chaperokine due to ability to modulate the immune response. Altered levels of eHSP70 are associated with various disease states. Larger clinical trial data on GLN effect on eHSP expression and eHSP70's association with inflammatory mediators and clinical outcomes in critical illness are limited.

OBJECTIVE

Explore effect of longitudinal change in serum eHSP70, eHSP27 and inflammatory cytokine levels on clinical outcomes such as pneumonia and mortality in adult surgical intensive care unit (SICU) patients. Further, evaluate effect of parenteral nutrition (PN) supplemented with GLN (GLN-PN) versus GLN-free, standard PN (STD-PN) on serum eHSP70 and eHSP27 concentrations.

METHODS

Secondary observational analysis of a multicenter clinical trial in 150 adults after cardiac, vascular, or gastrointestinal surgery requiring PN support and SICU care conducted at five academic medical centers. Patients received isocaloric, isonitrogenous PN, with or without GLN dipeptide. Serum eHSP70 and eHSP27, interleukin-6 (IL-6), and 8 (IL-8) concentrations were analyzed in patient serum at baseline (prior to study PN) and over 28 days of follow up.

RESULTS

eHSP70 declined over time in survivors during 28 days follow-up, but non-survivors had significantly higher eHSP70 concentrations compared to survivors. In patients developing pneumonia, eHSP70, eHSP27, IL-8, and IL-6 were significantly elevated. Adjusted relative risk for hospital mortality was reduced 75% (RR = 0.25, p = 0.001) for SICU patients with a faster decline in eHSP70. The area under the receiver operating characteristic curve was 0.85 (95% CI: 0.76 to 0.94) for the final model suggesting excellent discrimination between SICU survivors and non-survivors. GLN-PN did not alter eHSP70 or eHSP27 serum concentrations over time compared to STD-PN.

CONCLUSION

Our results suggest that serum HSP70 concentration may be an important marker for severity of illness and likelihood of recovery in the SICU. GLN-supplemented-PN did not increase eHSP70.

What is the evidence for the use of parenteral nutrition (PN) in critically ill surgical patients: a systematic review and meta-analysis

BACKGROUND

Malnutrition is associated with poor outcomes in surgical patients and corrective enteral feeding may not be possible. This is a particular problem in the acute setting where malnutrition is prevalent. The aim of this systematic review was to evaluate the use of parenteral nutrition (PN) in critically ill surgical patients.

METHODS

This review was registered with PROSPERO (CRD42017079567). Searches of the CENTRAL, EMBASE, and MEDLINE databases were performed using a predefined strategy. Randomised trials published in English since 1995, reporting a comparison of PN vs any comparator in a critically ill surgical population were included. The primary outcome was mortality. Risk of bias was assessed using the Cochrane risk of bias tool and the Grading of Recommendations Assessment, Development and Evaluation assessment. Meta-analysis was performed using a random effects model to assess variation in mortality and length of stay.

RESULTS

Fourteen RCTs were identified; standard PN was compared vs other forms of PN in ten studies, to PN with variable dose amino acids in one, and to enteral nutrition (EN) in three. In trials comparing glutamine-supplemented PN (PN-GLN) to PN, a non-significant reduction in mortality was noted (risk difference - 0.08. 95% CI - 0.17, 0.01, p = 0.08). A trend for a reduction in length of stay was seen in PN-GLN to PN comparator (mean reduction - 2.4, 95% CI - 7.19 to 2.32 days, I² = 92%). Impact on other outcome measures varied in direction of effect.

CONCLUSIONS

PN may offer benefit in critically ill surgical patients. The size and quality of studies lead to uncertainty around the estimates of clinical effect, meaning a robust trial is required.

Nutrition in the ICU: new trends versus old-fashioned standard enteral feeding?

PURPOSE OF REVIEW

The narrative review aims to summarize the relevant studies from the last 2 years and provide contextual information to understand findings.

RECENT FINDINGS

Recent ICU studies have provided insight in the pathophysiology and time course of catabolism, anabolic resistance, and metabolic and endocrine derangements interacting with the provision of calories and proteins.Early provision of high protein intake and caloric overfeeding may confer harm. Refeeding syndrome warrants caloric restriction and to identify patients at risk phosphate monitoring is mandatory.Infectious complications of parenteral nutrition are associated with overfeeding. In recent studies enteral nutrition is no longer superior over parenteral nutrition.Previously reported benefits of glutamine, selenium, and fish oil seem to have vanished in recent studies; however, studies on vitamin C, thiamine, and corticosteroid combinations show promising results.

SUMMARY

Studies from the last 2 years will have marked impact on future nutritional support strategies and practice guidelines for critical care nutrition as they challenge several old-fashioned concepts.

The gut in trauma

PURPOSE OF REVIEW

The purpose of this review is to describe established and emerging mechanisms of gut injury and dysfunction in trauma, describe emerging strategies to improve gut dysfunction, detail the effect of trauma on the gut microbiome, and describe the gut-brain connection in traumatic brain injury.

RECENT FINDINGS

Newer data suggest intraluminal contents, pancreatic enzymes, and hepatobiliary factors disrupt the intestinal mucosal layer. These mechanisms serve to perpetuate the inflammatory response leading to multiple organ dysfunction syndrome (MODS). To date, therapies to mitigate acute gut dysfunction have included enteral nutrition and immunonutrition; emerging therapies aimed to intestinal mucosal layer disruption, however, include protease inhibitors such as tranexamic acid, parenteral nutrition-supplemented bombesin, and hypothermia. Clinical trials to demonstrate benefit in humans are needed before widespread applications can be recommended.

SUMMARY

Despite resuscitation, gut dysfunction promotes distant organ injury. In addition, postresuscitation nosocomial and iatrogenic 'hits' exaggerate the immune response, contributing to MODS. This was a provocative concept, suggesting infectious and noninfectious causes of inflammation may trigger, heighten, and perpetuate an inflammatory response culminating in MODS and death. Emerging evidence suggests posttraumatic injury mechanisms, such as intestinal mucosal disruption and shifting of the gut microbiome to a pathobiome. In addition, traumatic brain injury activates the gut-brain axis and increases intestinal permeability.

Glutamine Administration Modulates Endothelial Progenitor Cell and Lung Injury in Septic Mice

This study investigated the effects of glutamine (GLN) administration on circulating endothelial progenitor cells (EPCs) and lung angiopoietin (Ang) gene expressions in polymicrobial sepsis. Mice were randomly assigned to a normal control group (NC), septic saline group (SS), and septic GLN group (SG). All mice were fed with a chow diet. Sepsis was induced by cecal ligation and puncture (CLP). The mice in SS group were injected with saline, whereas SG group administered 0.75 g GLN/kg body weight once via tail vein 1 h after CLP. Mice were killed 24 and 48 h after CLP. Their blood and lungs were collected for further analysis. The results showed that, compared with normal mice, sepsis resulted in higher C-X-C motif chemokine-12, vascular endothelial growth factor, nitric oxide levels, and a higher circulating EPC percentage. In addition, inflammatory cytokine concentrations and Ang-2 gene expression were upregulated in lung tissues. GLN administration enhanced the mobilization of EPC, and downregulated inflammatory cytokine production and the Ang-2 gene expressions in lungs. Histopathological findings showed that the extent of inflammatory lesions of the lung alveolar was less severe in the SG group than the SS group after CLP. Our results suggest that a single dose of intravenous GLN administration after initiation of sepsis promotes the mobilization of circulating EPC, and modulates the balance of Ang-Tie2 axis that may improve the vascular function, ameliorate inflammation, and protect lung injury against polymicrobial sepsis.

Efficacy of Early Enteral Immunonutrition on Immune Function and Clinical Outcome for Postoperative Patients With Gastrointestinal Cancer

BACKGROUND

Nutrition support is crucial for patients with gastrointestinal (GI) cancer after the operation. However, the controversy over the application of parenteral nutrition (PN) and early enteral immunonutrition (EEIN) has no determinate conclusion.

MATERIALS AND METHODS

We compared the effects of PN and EEIN on the postoperative nutrition condition, immune status, inflammation level, long-term survival, and quality of life of the patients with GI cancer. Seventy-eight patients were randomly divided into the PN group (n = 44) or EEIN group (n = 34). After an 8-day nutrition treatment, clinical and immunological parameters were evaluated.

RESULTS

The EEIN group had a significantly shorter hospital stay and higher body mass index level on postoperative day 30 than those in the PN group (P < .05). However, total hospital cost and incidences of short-term postoperative complications had no significant difference (P > .05). The percentages of CD4⁺ , natural killer, and natural killer T lymphocyte cells and the ratio of CD4⁺ /CD8⁺ in peripheral blood were significantly increased. Compared with the PN group, the EEIN group had a higher expression of activated cell surface markers such as CD27 and CD28. In addition, the secretion of interleukin (IL)-2 and interferon-γ was significantly higher, and the secretion of tumor necrosis factor-α and IL-10 was lower. Complication-free survival in the EEIN group were longer than those in the PN group (P = .04).

CONCLUSION

EEIN is superior to PN in improving nutrition status, enhancing immune function, and elevating quality of life.

Glutamine Administration in Early or Late Septic Phase Downregulates Lymphocyte PD-1/PD-L1 Expression and the Inflammatory Response in Mice With Polymicrobial Sepsis

BACKGROUND

Sepsis is a severe inflammatory response to infection. Excessive compensation to inflammation leads to dysregulated immune response that ultimately results in organ damage and lethality of sepsis. This study administered glutamine (GLN) in the early or late phase of sepsis to investigate its effects on regulating leukocyte programmed cell death 1 (PD-1) and its ligand (programmed cell death ligand 1 [PD-L1]) expression, macrophage function, inflammation, and acute kidney injury in sepsis.

METHODS

Mice were randomly assigned to cecal ligation and puncture (CLP) or sham-operated groups. Septic mice were respectively injected once with saline or 0.75 g GLN/kg body weight at 3 or 10 hours post-CLP via tail vein. All mice were sacrificed 24 hours after CLP.

RESULTS

Sepsis enhanced the percentage of interferon-γ-expressing and interleukin (IL)-17A-expressing CD4⁺ T cells, expression of PD-1 on T cells, and PD-L1 on B cells and monocytes. Inflammatory mediator messenger RNA (mRNA) expression in kidney tissues and proapoptotic caspase-3 mRNA expression in mesenteric lymph nodes were also upregulated. GLN administration decreased plasma IL-6 level, downregulated the percentage of IL-17A-expressing CD4⁺ T cells, attenuated macrophage dysfunction, decreased caspase-3 mRNA expression, and reduced PD-1/PD-L1 expression by T and B cells. Histological findings also showed that kidney damage was attenuated. GLN administered at 3 and 10 hours after CLP offered nearly equal effects on PD-1/PD-L1 and inflammatory mediator expression after CLP.

CONCLUSIONS

These findings suggest that a single dose of GLN administration in either the early or late phase during sepsis promotes a more balanced immune regulation and reduced systemic and kidney inflammatory responses in mice.

Influence of nutritional status on postoperative outcome in patients with colorectal cancer - the emerging role of the microbiome

Many patients with colorectal cancer are overweight. Even then, nutritional status is a frequently underestimated risk factor for perioperative complications. Enhanced Recovery after Surgery is the goal for perioperative management, and preoperative nutritional risk screening should be a standard. In case of nutritional risk, perioperative nutrition therapy should be started without delay and should follow recent guideline recommendations. The preservation of the microbiome has an emerging role in preventing postoperative anastomotic leakage and septic complications. The time window for recovery after neoadjuvant treatment for rectal cancer may be used for conditioning appropriate-risk patients in a “prehabilitation” program. In order to assess metabolic recovery and the prognosis for long-term survival, C-reactive protein/albumin ratio may be a promising parameter, which has to be validated in the future. This narrative review summarizes recent strategies and guideline recommendations.

ACERTO guidelines of perioperative nutritional interventions in elective general surgery

ABSTRACT Objective: to present recommendations based on the ACERTO Project (Acceleration of Total Post-Operative Recovery) and supported by evidence related to perioperative nutritional care in General Surgery elective procedures. Methods: review of relevant literature from 2006 to 2016, based on a search conducted in the main databases, with the purpose of answering guiding questions previously formulated by specialists, within each theme of this guideline. We preferably used randomized controlled trials, systematic reviews and meta-analyzes but also selected some cohort studies. We contextualized each recommendation-guiding question to determine the quality of the evidence and the strength of this recommendation (GRADE). This material was sent to authors using an open online questionnaire. After receiving the answers, we formalized the consensus for each recommendation of this guideline. Results: the level of evidence and the degree of recommendation for each item is presented in text form, followed by a summary of the evidence found. Conclusion: this guideline reflects the recommendations of the group of specialists of the Brazilian College of Surgeons, the Brazilian Society of Parenteral and Enteral Nutrition and the ACERTO Project for nutritional interventions in the perioperative period of Elective General Surgery. The prescription of these recommendations can accelerate the postoperative recovery of patients submitted to elective general surgery, with decrease in morbidity, length of stay and rehospitalization, and consequently, of costs.

Critical Care Nutrition: Where's the Evidence?

The surgical critically ill patient is subject to a variable and complex metabolic response, which has detrimental effects on immunity, wound healing, and preservation of lean body muscle. The concept of nutrition support has evolved into nutrition therapy, whereby the primary objectives are to prevent oxidative cell injury, modulate the immune response, and attenuate the metabolic response. This review outlines the metabolic response to critical illness, describes nutritional risk; reviews the evidence for the role, dose, and timing of enteral and parenteral nutrition, and reviews the evidence for immunonutrition in the surgical intensive care unit.

Significant Published Articles for Pharmacy Nutrition Support Practice in 2016

Purpose: To assist the pharmacist engaged in nutrition support therapy in staying current with pertinent literature. Methods: Several clinical pharmacists engaged in nutrition support therapy compiled a list of articles published in 2016 considered important to their clinical practice. The citation list was compiled into a single spreadsheet where the author participants were asked to assess whether the paper was considered important to nutrition support pharmacy practice. A culled list of publications was then identified whereby the majority of author participants (at least 5 out of 8) considered the paper to be important. Guideline and consensus papers from professional organizations, important to practice but not scored, were also included. Results: A total of 103 articles were identified; 10 from the primary literature were voted by the group to be of high importance. An additional 11 organizational guidelines, position, recommendation, or consensus papers were also identified. The top-ranked articles from the primary literature were reviewed. Conclusion: It is recommended that pharmacists, engaged in nutrition support therapy, be familiar with the majority of these articles as it pertains to their practice.

The gut microbiome and the mechanism of surgical infection

BACKGROUND

Since the very early days of surgical practice, surgeons have recognized the importance of considering that intestinal microbes might have a profound influence on recovery from surgical diseases such as appendicitis and peritonitis. Although the pathogenesis of surgical diseases such as cholelithiasis, diverticulosis, peptic ulcer disease and cancer have been viewed as disorders of host biology, they are emerging as diseases highly influenced by their surrounding microbiota.

METHODS

This is a review of evolving concepts in microbiome sciences across a variety of surgical diseases and disorders, with a focus on disease aetiology and treatment options.

RESULTS

The discovery that peptic ulcer disease and, in some instances, gastric cancer can now be considered as infectious diseases means that to advance surgical practice humans need to be viewed as superorganisms, consisting of both host and microbial genes. Applying this line of reasoning to the ever-ageing population of patients demands a more complete understanding of the effects of modern-day stressors on both the host metabolome and microbiome.

CONCLUSION

Despite major advances in perioperative care, surgeons today are witnessing rising infection-related complications following elective surgery. Many of these infections are caused by resistant and virulent micro-organisms that have emerged as a result of human progress, including global travel, antibiotic exposure, crowded urban conditions, and the application of invasive and prolonged medical and surgical treatment. A more complete understanding of the role of the microbiome in surgical disease is warranted to inform the path forward for prevention.

Effect of Previous High Glutamine Infusion on Inflammatory Mediators and Mortality in an Acute Pancreatitis Model

Parenteral glutamine supplementation in acute inflammatory conditions is controversial. We evaluated the inflammatory and survival responses after parenteral glutamine infusion in sodium taurocholate-induced acute pancreatitis (AP) model. Lewis rats received 1 g/kg parenteral glutamine (n = 42), saline (n = 44), or no treatment (n = 45) for 48 h before AP induction. Blood, lung, and liver samples were collected 2, 12, and 24 h after AP to measure serum cytokines levels and tissue heat shock protein (HSP) expression. From each group, 20 animals were not sacrificed after AP for a 7-day mortality study. Serum cytokine levels did not differ among groups at any time point, but the intragroup analysis over time showed higher interferon-γ only in the nontreatment and saline groups at 2 h (versus 12 and 24 h; both p ≤ 0.05). The glutamine group exhibited greater lung and liver HSP90 expression than did the nontreatment group at 2 and 12 h, respectively; greater liver HSP90 and HSP70 expression than did the saline group at 12 h; and smaller lung HSP70 and liver HSP90 expression than did the nontreatment group at 24 h (all p ≤ 0.019). The 7-day mortality rate did not differ among groups. In experimental AP, pretreatment with parenteral glutamine was safe and improved early inflammatory mediator profiles without affecting mortality.

When Is It Appropriate to Use Glutamine in Critical Illness?

Glutamine is a nonessential amino acid, which under trauma or critical illness can become essential. A number of historic small single-center randomized controlled trials (RCTs) have demonstrated positive treatment effects on clinical outcomes with glutamine supplementation. Meta-analyses based on these trials demonstrated a significant reduction in hospital mortality, intensive care unit (ICU) length of stay (LOS), and hospital LOS with intravenous (IV) glutamine. Similar results were not noted in 2 large multicenter RCTs (REDOXS and MetaPlus) assessing the efficacy of glutamine supplementation in ventilated ICU patients. The REDOXS trial of 40 ICUs randomized 1223 ventilated ICU patients to glutamine (IV and enteral), antioxidants, both glutamine and antioxidants, or placebo. The main conclusions were a trend toward increased 28-day mortality and significant increased hospital and 6-month mortality in those who received glutamine. The MetaPlus trial of 14 ICUs, which randomized 301 ventilated ICU patients to glutamine-enriched enteral vs an isocaloric diet, noted increased 6-month mortality in the glutamine-supplemented group. Newer RCTs have focused on specific populations and have demonstrated benefits in burn and elective surgery patients with glutamine supplementation. Whether larger studies will confirm these findings is yet to be determined. Recent American Society for Parenteral and Enteral Nutrition guidelines recommend that IV and enteral glutamine should not be used in the critical care setting based on the moderate quality of evidence available. We agree with these recommendations and would encourage larger multicenter studies to evaluate the risks and benefits of glutamine in burn and elective surgery patients.

Exogenous Glutamine in Respiratory Diseases: Myth or Reality?

Several respiratory diseases feature increased inflammatory response and catabolic activity, which are associated with glutamine depletion; thus, the benefits of exogenous glutamine administration have been evaluated in clinical trials and models of different respiratory diseases. Recent reviews and meta-analyses have focused on the effects and mechanisms of action of glutamine in a general population of critical care patients or in different models of injury. However, little information is available about the role of glutamine in respiratory diseases. The aim of the present review is to discuss the evidence of glutamine depletion in cystic fibrosis (CF), asthma, chronic obstructive pulmonary disease (COPD), acute respiratory distress syndrome (ARDS), and lung cancer, as well as the results of exogenous glutamine administration in experimental and clinical studies. Exogenous glutamine administration might be beneficial in ARDS, asthma, and during lung cancer treatment, thus representing a potential therapeutic tool in these conditions. Further experimental and large randomized clinical trials focusing on the development and progression of respiratory diseases are necessary to elucidate the effects and possible therapeutic role of glutamine in this setting.

Nutrition: A Primary Therapy in Pediatric Acute Respiratory Distress Syndrome

Appropriate nutrition is an essential component of intensive care management of children with acute respiratory distress syndrome (ARDS) and is linked to patient outcomes. One out of every two children in the pediatric intensive care unit (PICU) will develop malnutrition or have worsening of baseline malnutrition and present with specific micronutrient deficiencies. Early and adequate enteral nutrition (EN) is associated with improved 60-day survival after pediatric critical illness, and, yet, despite early EN guidelines, critically ill children receive on average only 55% of goal calories by PICU day 10. Inadequate delivery of EN is due to perceived feeding intolerance, reluctance to enterally feed children with hemodynamic instability, and fluid restriction. Underlying each of these factors is large practice variation between providers and across institutions for initiation, advancement, and maintenance of EN. Strategies to improve early initiation and advancement and to maintain delivery of EN are needed to improve morbidity and mortality from pediatric ARDS. Both, over and underfeeding, prolong duration of mechanical ventilation in children and worsen other organ function such that precise calorie goals are needed. The gut is thought to act as a "motor" of organ dysfunction, and emerging data regarding the role of intestinal barrier functions and the intestinal microbiome on organ dysfunction and outcomes of critical illness present exciting opportunities to improve patient outcomes. Nutrition should be considered a primary rather than supportive therapy for pediatric ARDS. Precise nutritional therapies, which are titrated and targeted to preservation of intestinal barrier function, prevention of intestinal dysbiosis, preservation of lean body mass, and blunting of the systemic inflammatory response, offer great potential for improving outcomes of pediatric ARDS. In this review, we examine the current evidence regarding dose, route, and timing of nutrition, current recommendations for provision of nutrition to children with ARDS, and the current literature for immune-modulating diets for pediatric ARDS. We will examine emerging data regarding the role of the intestinal microbiome in modulating the response to critical illness.