Perioperative intravenous glutamine supplemetation in major abdominal surgery for cancer: a randomized multicenter trial

Pharmaconutrition: Which substrates?

With the term "pharmaconutrition" or "immunonutrition" is intended the use of specific nutritional substrates having the ability of modulating specific mechanisms involved in several immune and inflammatory pathways. To achieve these goals, these substrates have to be administered with over physiologic dose. Glutamine and omega-3 polyunsaturated fatty acids, used as single substrate, did not show clear clinical advantages on solid endpoints such as postoperative complications. Despite several multiple substrate enteral feeds are available on the market, very few of them have been tested in randomized clinical trial to prove efficacy. The most extensive investigated formulation is a combination of arginine, omega-3 fatty acids, ribonucleic acid with or without glutamine. Several meta-analyses of randomized clinical trials have been conducted to compare the effects of enteral immunonutrition with control diets on post-surgical morbidity. The results consistently showed that the use of enteral multiple substrate formulas significantly reduced infectious complications and duration of hospitalization. In a more contemporary view, pharmaconutrition should be tested more accurately in the contest of enhanced recovery programs, during neoadjuvant chemotherapy, and in the prehabilitation setting.

Preoperative Glutamine Supplementation in Gastric Cancer-Thrombocyte Phagocytic Activity and Early Postoperative Outcomes

BACKGROUND

The aim of this study was to determine the phagocytic activity of thrombocytes in patients with gastric cancer and to assess the effect of oral and parenteral preoperative glutamine-based immunonutrition on nutritional status, thrombocyte phagocytic activity, and early postoperative outcomes.

METHODS

Patients suffering from invasive gastric cancer had been treated with preoperative immunonutrition with glutamine, and they were compared to patients without nutritional treatment. Nutritional status, percentage of weight loss, and BMI were assessed. Levels of total protein, albumin, cholesterol, triglycerides, platelets, and their phagocytic ability were measured twice. Postsurgical complications were assessed via the Clavien-Dindo classification.

RESULTS

Group I consisted of 20 patients with an oral glutamine-10 g daily. Group II had 38 patients who received intravenous glutamine, 1.5 mL per kg body weight of Dipeptiven. Group III consisted of 25 patients who did not receive preoperative immunonutrition. In total, 47% of patients in Group I, 54% of patients in Group II, and 33% of patients in Group III were malnourished. In Group I, the percentage of phagocytizing platelet (%PhP) was 1.1 preoperatively and 1.2 postoperatively. The phagocytic index (PhI) was 1.0 and 1.1. In Group II, %PhP was 1.1 and 1.2 and PhI was 1.0 and 1.1. In Group III, the %PhP was 1.0 and 1.2 and PhI was 1.0 and 1.1. An increase in triglyceride level was observed in both immunonutrition groups. There was a decline in total protein and albumin level in Group II. In Group III, there was a decline in total protein, albumin, and cholesterol level. The total platelet count and PhI were increased in both immunonutrition groups. There was also a rise in %PhP in Group II. In Group III, there was a rise in blood platelet level, %PhP, and PhI. The complication rates were 53% in Group I, 29% in Group II, and 40% in Group III.

CONCLUSIONS

In invasive gastric cancer, laboratory nutritional parameters are significantly reduced, causing malnutrition in 44.7% of patients. Oral glutamine supplementation inhibited the postoperative decline in protein metabolism parameters; however, this did not affect the reduction in the percentage of postoperative complications. Glutamine used preoperatively significantly reduced the percentage of serious surgical complications, regardless of the way it was supplemented. Patients with invasive gastric cancer have a significant decrease in platelet phagocytic activity. The administered preoperative parenteral nutrition and the surgical procedure itself influenced the improvement of the phagocytic activity of blood platelets. Glutamine did not have this effect, regardless of the route of administration.

Postoperative parenteral glutamine supplementation improves the short-term outcomes in patients undergoing colorectal cancer surgery: A propensity score matching study

Introduction

The clinical utility of glutamine in patients undergoing colorectal cancer (CRC) surgery remains unclear. Therefore, we aimed to investigate the impact of postoperative treatment with glutamine on postoperative outcomes in patients undergoing CRC surgery.

Methods

We included patients with CRC undergoing elective surgery between January 2014 and January 2021. Patients were divided into the glutamine and control groups. We retrospectively analyzed postoperative infections complications within 30 days and other outcomes using propensity score matching and performed between-group comparisons.

Results

We included 1,004 patients who underwent CRC surgeries; among them, 660 received parenteral glutamine supplementation. After matching, there were 342 patients in each group. The overall incidence of postoperative complications was 14.9 and 36.8% in the glutamine and control groups, respectively, indicating that glutamine significantly reduced the incidence of postoperative complications [p < 0.001; risk ratio (RR) 0.41 [95% CI 0.30–0.54]]. Compared with the control group, the glutamine group had a significantly lower postoperative infection complications rate (10.5 vs. 28.9%; p < 0.001; RR 0.36 [95% CI 0.26–0.52]). Although there was no significant between-group difference in the time to first fluid diet (p = 0.052), the time to first defecation (p < 0.001), first exhaust (p < 0.001), and first solid diet (p < 0.001), as well as hospital stay (p < 0.001) were significantly shorter in the glutamine group than in the control group. Furthermore, glutamine supplementation significantly reduced the incidence of postoperative intestinal obstruction (p = 0.046). Moreover, glutamine supplementation alleviated the decrease in albumin (p < 0.001), total protein (p < 0.001), and prealbumin levels (p < 0.001).

Conclusions

Taken together, postoperative parenteral glutamine supplementation can effectively reduce the incidence of postoperative complications, promote the recovery of intestinal function, and improve albumin levels in patients undergoing CRC surgery.

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.

Preoperative Nutritional Optimization of the Oncology Patient: A Scoping Review

BACKGROUND

Malnutrition is common among patients with cancer and is a known risk factor for poor postoperative outcomes; however, preoperative nutritional optimization guidelines are lacking in this high-risk population. The objective of this study was to review the evidence regarding preoperative nutritional optimization of patients undergoing general surgical operations for the treatment of cancer.

METHODS

A literature search was performed across the Ovid (MEDLINE), Cochrane Library (Wiley), Embase (Elsevier), CINAHL (EBSCOhost), and Web of Science (Clarivate) databases. Eligible studies included randomized clinical trials, observational studies, reviews, and meta-analyses published between 2010 and 2020. Included studies evaluated clinical outcomes after preoperative nutritional interventions among adult patients undergoing surgery for gastrointestinal cancer. Data extraction was performed using a template developed and tested by the study team.

RESULTS

A total of 5,505 publications were identified, of which 69 studies were included for data synthesis after screening and full text review. These studies evaluated preoperative nutritional counseling, protein-calorie supplementation, immunonutrition supplementation, and probiotic or symbiotic supplementation.

CONCLUSIONS

Preoperative nutritional counseling and immunonutrition supplementation should be considered for patients undergoing surgical treatment of gastrointestinal malignancy. For malnourished patients, protein-calorie supplementation should be considered, and for patients undergoing colorectal cancer surgery, probiotics or symbiotic supplementation should be considered.

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.

Effects of nutritional support on the clinical outcomes of well-nourished patients with cancer: a meta-analysis

The effects of nutritional support on well-nourished patients have been investigated, but the results were inconsistent among different articles. We performed the meta-analysis to examine the existing evidence. We systematically retrieved articles from PubMed, Web of Science and the Cochrane Library to identify the evidence of nutritional support for well-nourished patients. Methodological quality assessment was assessed based on the Cochrane Handbook and GRADE. Nine randomized controlled trials (RCTs) and one non-RCT with 1400 participants were included in this meta-analysis. Nutritional support, particularly immunonutrition, was associated with a significant reduction in postoperative infectious complications (OR = 0.74, 95% CI: 0.57-0.96), and a decreasing trends in morbidity and the length of the hospital stay (LOS) were observed. However, the mortality rates were comparable between two groups. The quality of evidence was moderate to high. Nutritional support, particularly immunonutrition supplementation, is likely to reduce infectious complications, morbidity and LOS without influencing mortality and may be a safe and preferred choice for well-nourished patients undergoing surgery for cancer. However, additional RCTs are warranted to determine the effects of nutritional support on well-nourished patients.

Immunonutrition vs Standard Nutrition for Cancer Patients: A Systematic Review and Meta-Analysis (Part 1)

The aim of this study was to determine the efficacy of immunonutrition vs standard nutrition in cancer patients treated with surgery. Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, EBSCOhost, and Web of Science were searched. Sixty-one randomized controlled trials were included. Immunonutrition was associated with a significantly reduced risk of postoperative infectious complications (risk ratio [RR] 0.71 [95% CI, 0.64-0.79]), including a reduced risk of wound infection (RR 0.72 [95% CI, 0.60-0.87]), respiratory tract infection (RR 0.70 [95% CI, 0.59-0.84]), and urinary tract infection (RR 0.69 [95% CI, 0.51-0.94]) as well as a decreased risk of anastomotic leakage (RR 0.70 [95% CI, 0.53-0.91]) and a reduced hospital stay (MD -2.12 days [95% CI -2.72 to -1.52]). No differences were found between the 2 groups with regard to sepsis or all-cause mortality. Subgroup analyses revealed that receiving arginine + nucleotides + ω-3 fatty acids and receiving enteral immunonutrition reduced the rates of wound infection and respiratory tract infection. The application of immunonutrition at 25-30 kcal/kg/d for 5-7 days reduced the rate of respiratory tract infection. Perioperative immunonutrition reduced the rate of wound infection. For malnourished patients, immunonutrition shortened the hospitalization time. Therefore, immunonutrition reduces postoperative infection complications and shortens hospital stays but does not reduce all-cause mortality. Patients who are malnourished before surgery who receive arginine + nucleotides + ω-3 fatty acids (25-30 kcal/kg/d) via the gastrointestinal tract during the perioperative period (5-7 days) may show better clinical efficacy.

Heterogeneity of nutrition care procedures in nutrition guidelines for cancer patients

OBJECTIVES

The aim of this study was to systematically assess the nutrition care procedures in nutrition guidelines for cancer patients and identify gaps limiting evidence-based practise.

METHODS

A systematic search of databases and websites was conducted to identify nutrition guidelines for cancer patients. The quality of the eligible guidelines was evaluated by using the Appraisal of Guidelines for Research and Evaluation (AGREE II). The Measurement Scale of Rate of Agreement (MSRA) was used to assess the scientific agreement of formulated recommendations for nutrition care procedures in the guidelines (2017-2019), and evidence supporting these recommendations was extracted and analysed.

RESULTS

Seventeen nutrition guidelines for cancer patients were identified. Only European Society for Clinical Nutrition and Metabolism (ESPEN) and Australian guidelines have a total quality score of more than 60%, which is worthy of clinical recommendation. Twelve guidelines (2017-2019) were included to further analyse the heterogeneity and causes of nutrition care procedures, and we found that the content and tools of nutrition screening and assessment, the application of immune nutrients, and the selection of nutritional support pathways were heterogeneous. The main reasons for the heterogeneity of nutrition care procedures were insufficient attention to nutrition risk screening, differences in recommendations for nutrition assessment, immune nutrients and nutritional support, unreasonable citation of screening and assessment evidence, preference of developers, and lack of evidence of high-quality research on energy and nitrogen demand. In addition, the fairness and propensity of the guidelines for the selection of evidence for different cancer patients are also potential reasons for the heterogeneity of nutritional care procedures.

CONCLUSIONS

The quality of the nutrition guidelines for cancer patients was highly variable. The nutrition care procedures were heterogeneous among the different guidelines in the last 3 years. Specific improvement of the factors leading to the heterogeneity of nutrition care procedures will be a reasonable and effective way for developers to upgrade the nutrition care procedures in the guidelines for cancer patients.

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.

Meta-analysis of immunonutrition in major abdominal surgery

Background

The objective of this study was to evaluate the potential benefits of immunonutrition in major abdominal surgery with special regard to subgroups and influence of bias.

Methods

A systematic literature search from January 1985 to July 2015 was performed in MEDLINE, Embase and CENTRAL. Only RCTs investigating immunonutrition in major abdominal surgery were included. Outcomes evaluated were mortality, overall complications, infectious complications and length of hospital stay. The influence of different domains of bias was evaluated in sensitivity analyses. Evidence was rated according to the GRADE Working Group grading of evidence.

Results

A total of 83 RCTs with 7116 patients were included. Mortality was not altered by immunonutrition. Taking all trials into account, immunonutrition reduced overall complications (odds ratio (OR) 0·79, 95 per cent c.i. 0·66 to 0·94; P = 0·01), infectious complications (OR 0·58, 0·51 to 0·66; P < 0·001) and shortened hospital stay (mean difference –1·79 (95 per cent c.i. –2·39 to –1·19) days; P < 0·001) compared with control groups. However, these effects vanished after excluding trials at high and unclear risk of bias. Publication bias seemed to be present for infectious complications (P = 0·002). Non-industry-funded trials reported no positive effects for overall complications (OR 1·13, 0·88 to 1·46; P = 0·34), whereas those funded by industry reported large effects (OR 0·66, 0·48 to 0·91; P = 0·01).

Conclusion

Immunonutrition after major abdominal surgery did not seem to alter mortality (GRADE: high quality of evidence). Immunonutrition reduced overall complications, infectious complications and shortened hospital stay (GRADE: low to moderate). The existence of bias lowers confidence in the evidence (GRADE approach).

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.

Effect of glutamine enriched nutrition support on surgical patients with gastrointestinal tumor: a meta-analysis of randomized controlled trials

Background:

Associations between glutamine (Gln) enriched nutrition support and surgical patients with gastrointestinal (GI) tumor remain controversy. The purpose of this meta-analysis was to assess the effect of Gln enriched nutrition support on surgical patients with GI tumor in term of relevant biochemical indices, immune indices, and clinical outcomes.

Methods:

Six databases were systematically searched to find eligible randomized controlled trials (RCTs) from 1966 to May 2014. When estimated the analysis indexes, the relative risk (RR) was used as the effect size of the categorical variable, while the weighted mean difference (MD) was used as the effect size of a continuous variable. Meta-analysis was conducted with Rev Man 5.2.

Results:

Thirteen RCTs, involving 1034 patients, were included in the meta-analysis. The analysis showed that Gln enriched nutrition support was more effective in increasing serum albumin (MD: 0.10; 95% confidence interval [CI]: 0.02–0.18; P < 0.05), serum prealbumin (MD: 1.98; 95% CI: 1.40–2.55; P < 0.05) and serum transferring (MD: 0.35; 95% CI: 0.12–0.57; P < 0.05), concentration of IgG (MD: 1.26; 95% CI: 0.90–1.63; P < 0.05), IgM (MD: 0.18; 95% CI: 0.11–0.25; P < 0.05), IgA (MD: 0.22; 95% CI: 0.10–0.33; P < 0.05), CD3⁺ (MD: 3.71; 95% CI: 2.57–4.85; P < 0.05) and CD4/CD8 ratio (MD: 0.27; 95% CI: 0.12–0.42; P < 0.05). Meanwhile, it was more significant in decreasing the incidence of infectious complications (RR: 0.67; 95% CI: 0.50–0.90; P < 0.05) and shortening the length of hospital stay (MD: −1.72; 95% CI: −3.31–−0.13; P < 0.05).

Conclusions:

Glutamine enriched nutrition support was superior in improving immune function, reducing the incidence of infectious complications and shortening the length of hospital stay, playing an important role in the rehabilitation of surgical GI cancer patients.

Glutamine Supplementation in Intensive Care Patients: A Meta-Analysis of Randomized Clinical Trials

The role of glutamine (GLN) supplementation in critically ill patients is controversial. Our aim was to analyze its potential effect in patients admitted to intensive care unit (ICU).We performed a systematic literature review through Medline, Embase, Pubmed, Scopus, Ovid, ISI Web of Science, and the Cochrane-Controlled Trials Register searching for randomized clinical trials (RCTs) published from 1983 to 2014 and comparing GLN supplementation to no supplementation in patients admitted to ICU. A random-effect meta-analysis for each outcome (hospital and ICU mortality and rate of infections) of interest was carried out. The effect size was estimated by the risk ratio (RR).Thirty RCTs were analyzed with a total of 3696 patients, 1825 (49.4%) receiving GLN and 1859 (50.6%) no GLN (control groups). Hospital mortality rate was 27.6% in the GLN patients and 28.6% in controls with an RR of 0.93 (95% CI = 0.81-1.07; P = 0.325, I = 10.7%). ICU mortality was 18.0 % in the patients receiving GLN and 17.6% in controls with an RR of 1.01 (95% CI = 0.86-1.19; P = 0.932, I = 0%). The incidence of infections was 39.7% in GLN group versus 41.7% in controls. The effect of GLN was not significant (RR = 0.88; 95% CI = 0.76-1.03; P = 0.108, I = 56.1%).These results do not allow to recommend GLN supplementation in a generic population of critically ills. Further RCTs are needed to explore the effect of GLN in more specific cohort of patients.

Uncertainty about the safety of supplemental glutamine: an editorial on "A randomized trial of glutamine and antioxidants in critically ill patients"

Previously small randomized clinical trials and several meta-analyses have suggested improved patient outcomes from parenteral glutamine supplementation. A recent large multi-center randomized trial conducted in critically ill patients with documented multiple organ failure at enrollment demonstrated an increase in mortality among those receiving supplemental glutamine. This article discusses the discrepancies in trial outcomes and the risks associated with glutamine administration during critical illness.

Effect of glutamine dipeptide supplementation on primary outcomes for elective major surgery: systematic review and meta-analysis

To evaluate if glutamine (GLN) supplementation may affect primary outcomes in patients undergoing major elective abdominal operations, we performed a systematic literature review of randomized clinical trials (RCTs) published from 1983 to 2013 and comparing intravenous glutamine dipeptide supplementation to no supplementation in elective surgical abdominal procedures. A meta-analysis for each outcome (overall and infectious morbidity and length of stay) of interest was carried out. The effect size was estimated by the risk ratio (RR) or by the weighted mean difference (WMD). Nineteen RCTs were identified with a total of 1243 patients (640 receiving GLN and 603 controls). In general, the studies were underpowered and of medium or low quality. GLN supplementation did not affect overall morbidity (RR = 0.84, 95% CI 0.51 to 1.36; p = 0.473) and infectious morbidity (RR = 0.64; 95% CI = 0.38 to 1.07; p = 0.087). Patients treated with glutamine had a significant reduction in length of hospital stay (WMD = -2.67; 95% CI = -3.83 to -1.50; p < 0.0001). In conclusion, GLN supplementation appears to reduce hospital stay without affecting the rate of complications. The positive effect of GLN on time of hospitalization is difficult to interpret due to the lack of significant effects on surgery-related morbidity.

Appropriate use of parenteral nutrition through the perioperative period

Recent advances in nutrition therapy of the patient undergoing elective surgery have focused on greater utilization of the gut, feeding closer to the time of surgery, avoiding extensive bowel preparations or use of nasogastric tubes and drains, and measures to promote and maintain intestinal motility. Failure to have protocols in place for delivery of enteral nutrition (EN) through the perioperative period should not lead to inappropriate use of parenteral nutrition (PN) as a default therapy, because in many circumstances, standard therapy with no specialized nutrition support may be associated with better outcome. In cases where EN is not feasible and the patient shows evidence of malnutrition, surgery should be delayed 7-10 days to provide perioperative PN. For patients requiring urgent surgery where EN is not feasible, the initiation of PN postoperatively should be delayed 5-7 days. Whether alternative sources for lipid emulsion and availability of parenteral immune-modulating agents in the future can improve the risk/benefit ratio of PN and expand its use through the perioperative period awaits further study.

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.

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.

Clinical application of immune-enhanced enteral nutrition in patients with advanced gastric cancer after total gastrectomy

OBJECTIVE

To determine whether immune-enhanced enteral nutrition (EN) was effective on nutritional status, immune function, surgical outcomes and days of hospitalization after total gastrectomy for patients with advanced gastric cancer (AGC).

METHODS

From August 2005 to May 2011, 78 patients with AGC who underwent a total gastrectomy were enrolled and divided randomly into three groups: immune-enhanced EN (EN + glutamine [Gln]) group, standard EN group and control group. Serum parameters including total protein, albumin, proalbumin and transferrin were examined on preoperative day 1, postoperative day 2 and day 12. Levels of immunoglobulin M (IgM), immunoglobulin G (IgG), natural killer (NK) cells, CD4⁺ and CD8⁺ T cells were also compared.

RESULTS

The formulas were tolerated well in all the patients except 5 with mild complications. The EN + Gln and EN groups showed a faster onset of flatus and shorter hospitalization duration than the control group. On postoperative day 12, serum total protein, albumin, proalbumin and transferrin levels of the EN + Gln and EN groups were significantly higher than those of the control group (P < 0.05). CD4⁺ T cells, NK cells, IgM and IgG levels of the EN + Gln group increased prominently, and were significantly higher than those before the operation as well as those in the EN and control groups.

CONCLUSION

Immune-enhanced EN can improve nutritional status and immune function for the patients with AGC after total gastrectomy.

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.

Safety, feasibility, and tolerance of early oral feeding after colorectal resection outside an enhanced recovery after surgery (ERAS) program

INTRODUCTION

It is generally believed that resumption of feeding after colorectal resection is indicated only after recovery of bowel function. This study was designed to verify safety, feasibility, and tolerance of early oral postoperative feeding (EOF) outside an enhanced recovery after surgery (ERAS) program.

MATERIALS AND METHODS

One hundred patient candidates to elective colorectal resection were prospectively enrolled in an EOF program. Feeding was started on postoperative day (POD) 1 with oral nutritional supplement (ONS). On POD 2, patients had normal food plus ONS to reach 1,000-1,200 kcal/day with progressive increase until 1,800-2,000 kcal/day. Results were compared with historical controls (n = 100) in whom oral feeding was allowed only after full bowel function recovery. The ERAS program was not applied in both groups.

RESULTS

The EOF group had a better recovery of short half-life protein synthesis compared with the control group (P < 0.001). Stool canalization occurred after a median of 3 days (range, 1-6 days) in the EOF group versus 5 days (range, 2-8 days) in the control group (P = 0.001). The feeding protocol was completed in 89 patients within POD 5. Tolerance to resumption of feeding was similar in the two groups. The overall rate of postoperative complication was 22% in the EOF group vs. 27% in the control group (P = 0.51). The median length of hospitalization was 9 days (range, 6-25 days) in the EOF group vs. 12 days (range, 6-31 days) in controls (P = 0.01).

CONCLUSIONS

EOF after colorectal operations is feasible and safe outside an ERAS program.

Perioperative nutrition in abdominal surgery: recommendations and reality

Introduction. Preoperative malnutrition is a major risk factor for increased postoperative morbidity and mortality. Definition and diagnosis of malnutrition and its treatment is still subject for controversy. Furthermore, practical implementation of nutrition-related guidelines is unknown. Methods. A review of the available literature and of current guidelines on perioperative nutrition was conducted. We focused on nutritional screening and perioperative nutrition in patients undergoing digestive surgery, and we assessed translation of recent guidelines in clinical practice. Results and Conclusions. Malnutrition is a well-recognized risk factor for poor postoperative outcome. The prevalence of malnutrition depends largely on its definition; about 40% of patients undergoing major surgery fulfil current diagnostic criteria of being at nutritional risk. The Nutritional Risk Score is a pragmatic and validated tool to identify patients who should benefit from nutritional support. Adequate nutritional intervention entails reduced (infectious) complications, hospital stay, and costs. Preoperative oral supplementation of a minimum of five days is preferable; depending on the patient and the type of surgery, immune-enhancing formulas are recommended. However, surgeons' compliance with evidence-based guidelines remains poor and efforts are necessary to implement routine nutritional screening and nutritional support.

Immunonutrition in gastrointestinal surgery

BACKGROUND

Patients undergoing major gastrointestinal surgery are at increased risk of developing complications. The use of immunonutrition (IN) in such patients is not widespread because the available data are heterogeneous, and some show contradictory results with regard to complications, mortality and length of hospital stay.

METHODS

Randomized controlled trials (RCTs) published between January 1985 and September 2009 that assessed the clinical impact of perioperative enteral IN in major gastrointestinal elective surgery were included in a meta-analysis.

RESULTS

Twenty-one RCTs enrolling a total of 2730 patients were included in the meta-analysis. Twelve were considered as high-quality studies. The included studies showed significant heterogeneity with respect to patients, control groups, timing and duration of IN, which limited group analysis. IN significantly reduced overall complications when used before surgery (odds ratio (OR) 0·48, 95 per cent confidence interval (c.i.) 0·34 to 0·69), both before and after operation (OR 0·39, 0·28 to 0·54) or after surgery (OR 0·46, 0·25 to 0·84). For these three timings of IN administration, ORs of postoperative infection were 0·36 (0·24 to 0·56), 0·41 (0·28 to 0·58) and 0·53 (0·40 to 0·71) respectively. Use of IN led to a shorter hospital stay: mean difference -2·12 (95 per cent c.i. -2·97 to -1·26) days. Beneficial effects of IN were confirmed when low-quality trials were excluded. Perioperative IN had no influence on mortality (OR 0·90, 0·46 to 1·76).

CONCLUSION

Perioperative enteral IN decreases morbidity and hospital stay but not mortality after major gastrointestinal surgery; its routine use can be recommended.

Amino acid composition in parenteral nutrition: what is the evidence?

PURPOSE OF REVIEW

Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years.

RECENT FINDINGS

Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition.

SUMMARY

Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition.

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.