Effect of Timing of Pharmaconutrition (Immunonutrition) Administration on Outcomes of Elective Surgery for Gastrointestinal Malignancies

A review of perioperative immune-modulating and metabolic-modulating nutrition strategies for bowel resection surgery

Focused perioperative nutrition strategies have proven benefits on the outcomes for patients undergoing major abdominal surgery. In this brief article, we will review these strategies and the evidence to support them with a focus on gastrointestinal anastomotic healing. We will elaborate the risks and benefits of enteral feeds, immune- and metabolic-modulating formulas, prebiotics and probiotics, and prehabilitation in preparation for surgery. Additionally, we will discuss the role of fish oils (eicosapentaenoic acid and docosahexaenoic acid) in the surgical patient and new data on specialized proresolving mediators in inflammation resolution. Finally, this article will consider the harmful impact surgical trauma has on the microbiome and the potential for perioperative dietary modulation to attenuate these negative effects.

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.

Hepatopancreaticobiliary Resection Arginine Immunomodulation (PRIMe) trial: protocol for a randomised phase II trial of the impact of perioperative immunomodulation on immune function following resection for hepatopancreaticobiliary malignancy

INTRODUCTION

Surgical stress results in immune dysfunction, predisposing patients to infections in the postoperative period and potentially increasing the risk of cancer recurrence. Perioperative immunonutrition with arginine-enhanced diets has been found to potentially improve short-term and cancer outcomes. This study seeks to measure the impact of perioperative immunomodulation on biomarkers of the immune response and perioperative outcomes following hepatopancreaticobiliary surgery.

METHODS AND ANALYSIS

This is a 1:1:1 randomised, controlled and blinded superiority trial of 45 patients. Baseline and perioperative variables were collected to evaluate immune function, clinical outcomes and feasibility outcomes. The primary outcome is a reduction in natural killer cell killing as measured on postoperative day 1 compared with baseline between the control and experimental cohorts.

ETHICS AND DISSEMINATION

This trial has been approved by the research ethics boards at participating sites and Health Canada (parent control number: 223646). Results will be distributed widely through local and international meetings, presentation, publication and ClinicalTrials.gov (identifier: NCT04549662). Any modifications to the protocol will be communicated via publications and ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT04549662.

Impact of Perioperative Immunonutrition on Postoperative Outcomes for Patients Undergoing Head and Neck or Gastrointestinal Cancer Surgeries: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To clarify whether perioperative immunonutrition is effective in adult patients with or without malnutrition undergoing elective surgery for head and neck (HAN) or gastrointestinal (GI) cancers.

BACKGROUND

It is important to avoid postoperative complications in patients with cancer as they can compromise clinical outcomes. There is no consensus on the efficacy of perioperative immunonutrition in patients with or without malnutrition undergoing HAN or GI cancer surgery.

MATERIALS AND METHODS

We searched MEDLINE (PubMed), MEDLINE (OVID), EMBASE, Cochrane Central Register of Controlled Trials, Web of Science Core Selection, and Emcare from 1981 to 2022 using search terms related to immunonutrition and HAN or GI cancer. We included randomized controlled trials. Intervention was defined as immunonutritional therapy including arginine, n-3 omega fatty acids, or glutamine during the perioperative period. The control was defined as standard nutritional therapy. The primary outcomes were total postoperative and infectious complications, defined as events with a Clavien-Dindo classification grade ≥ II that occurred within 30 days after surgery.

RESULTS

Of the 4825 patients from 48 included studies, 19 had upper GI cancer, 9 had lower, and 8 had mixed cancer, whereas 12 had HAN cancers. Immunonutrition reduced the total postoperative complications (relative risk ratio: 0.78; 95% CI, 0.66-0.93; certainty of evidence: high) and infectious complications (relative risk ratio: 0.71; 95% CI, 0.61-0.82; certainty of evidence: high) compared with standard nutritional therapy.

CONCLUSIONS

Nutritional intervention with perioperative immunonutrition in patients with HAN and GI cancers significantly reduced total postoperative complications and infectious complications.

Impact of Perioperative Immunonutrition on Postoperative Outcomes in Patients with Upper Gastrointestinal Cancer: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

There is no consensus on the efficacy of perioperative immunonutrition in patients with upper gastrointestinal (GI) cancer surgery. We clarified the impact of perioperative immunonutrition on postoperative outcomes in patients with upper GI cancers. We searched MEDLINE (PubMed), MEDLINE (OVID), EMBASE, Cochrane Central Register of Controlled Trials, Web of Science Core Selection, and Emcare from 1981-2022 using search terms related to immunonutrition and upper GI cancer. We included randomized controlled trials. Intervention was defined as immunonutritional therapy, including arginine, n-3 omega fatty acids, or glutamine during the perioperative period. The control was defined as standard nutritional therapy. The primary outcomes were infectious complications, defined as events with a Clavien-Dindo classification grade ≥ II that occurred within 30 days after surgery. After screening, 23 studies were included in the qualitative synthesis and in the quantitative synthesis. The meta-analysis showed that immunonutrition reduced infectious complications (relative risk ratio: 0.72; 95% confidence interval: 0.57-0.92; certainty of evidence: Moderate) compared with standard nutritional therapy. In conclusion, nutritional intervention with perioperative immunonutrition in patients with upper GI cancers significantly reduced infectious complications. The effect of immunonutrition for upper GI cancers in reducing the risk of infectious complications was about 30%.

Immunonutrition vs standard nutrition for patients with cancer

The prevailing belief in the value of immunonnutrition has been questioned as different patient populations show variable responses ranging from no benefit or even harm to significant improvements in clinical outcomes. The subject of this invited review is a previously published meta-analysis that showed important benefits from the perioperative use of an immunonutrition formula (defined as nutrition therapy that contains specific immune-modulating agents) in a distinct population: adult patients with cancer undergoing an elective major surgical operation. Findings showed that use of an immunonutrition formula was associated with reduced infectious morbidity, anastomotic leakage, hospital length of stay, and postoperative complications compared with standard formulations. These benefits were seen after adjusting for bias and removal of older publications. Issues, such as dosing, duration of therapy, baseline nutrition status, content of specific immunomodulatory agents, and route of delivery that contributed to the beneficial response, were discussed. Little difference in response was seen between well-nourished and malnourished patients, but geographic differences were seen, with greater outcome benefits seen in studies originating from Europe than from Asia or the United States. The best results were seen when at least three agents (arginine, fish oil, and RNA nucleotides) were given, with the timing of the delivery occurring throughout the perioperative period. A review of this meta-analysis is warranted because it shows a consistent benefit from such therapy over 30 years of clinical research, provides a detailed subset analysis of related issues, and highlights its value in improving outcome in this patient population.

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.

Perioperative arginine prevents metastases by accelerating natural killer cell recovery after surgery

Profound natural killer (NK) cell suppression after cancer surgery is a main driver of metastases and recurrence, for which there is no clinically approved intervention available. Surgical stress is known to cause systemic postoperative changes that negatively modulate NK cell function including the expansion of surgery-induced myeloid-derived suppressor cells (Sx-MDSCs) and a marked reduction in arginine bioavailability. In this study, we determine that Sx-MDSCs regulate systemic arginine levels in the postoperative period and that restoring arginine imbalance after surgery by dietary intake alone was sufficient to significantly reduce surgery-induced metastases in our preclinical murine models. Importantly, the effects of perioperative arginine were dependent upon NK cells. Although perioperative arginine did not prevent immediate NK cell immunoparalysis after surgery, it did accelerate their return to preoperative cytotoxicity, interferon gamma secretion, and activating receptor expression. Finally, in a cohort of patients with colorectal cancer, postoperative arginine levels were shown to correlate with their Sx-MDSC levels. Therefore, this study lends further support for the use of perioperative arginine supplementation by improving NK cell recovery after surgery.

A Translational Randomized Trial of Perioperative Arginine Immunonutrition on Natural Killer Cell Function in Colorectal Cancer Surgery Patients

BACKGROUND

Surgery results in severe impairment of natural killer (NK) cell cytotoxicity (NKC) and activity (NKA, cytokine secretion), and a dramatic drop in arginine levels. Postoperative immunosuppression is associated with increased complications and recurrence. Perioperative arginine is reported to reduce postoperative complications. Because arginine modulates NK cell function, this study aimed to determine whether perioperative consumption of arginine-enriched supplements (AES) can improve NK cell function in colorectal cancer (CRC) surgery patients.

METHODS

This study randomized 24 CRC patients to receive the AES or isocaloric/isonitrogenous control supplement three times a day for five days before and after surgery. The AES contained 4.2 g of arginine per dose (12.6 g/day). The primary objective was to determine whether AES improved NKC by 50 % compared with the control group after surgery.

RESULTS

On surgery day (SD) 1, NKC was significantly reduced postoperatively in the control group by 50 % (interquartile range [IQR], 36-55 %; p = 0.02) but not in the AES group (25 % reduction; IQR, 28-75 %; p = 0.3). Furthermore, AES had no benefit in terms of NKA or NK cell number. Compliance was much greater preoperatively (>91 %) than postoperatively (<46 %). However, despite excellent preoperative compliance, arginine was rapidly cleared from the blood within 4 h after consumption and therefore, did not prevent the postoperative drop in arginine.

CONCLUSIONS

Oral consumption of arginine immunonutrition resulted in a modest improvement in NKC after surgery but was unable to prevent postoperative arginine depletion or the suppression of NKA (ClinicalTrials.gov NCT02987296).

Nutritional impact of omega 3 fatty acids and metabolites in acute and chronic critical illness

PURPOSE OF REVIEW

Lipids have been utilized historically as a calorie dense means to ensure delivery of essential fatty acids (FA). Since the development of mixed lipid emulsion and investigation of immunomodulatory formulas, there has been an awakening that not all lipids are created equal. This narrative review focuses on contemporary evidence in the utilization of lipids (namely omega 3 fatty acids) in both acute and chronic critical illness.

RECENT FINDINGS

Though randomized control trials and meta-analyses provide little guidance regarding clinical practice for patients suffering from chronic critical illness, available literature suggests the potential to use lipid formulas to decrease the inflammatory cycle that drives catabolism. Additionally, this review will address the expanding evidence that specialized pro-resolving mediators (SPMs) may be the future of immunomodulating inflammation in acute and chronic critical illness and the persistent inflammation, immunosuppression, and catabolic syndrome (PICS).

SUMMARY

Although societal guidelines, expert consensus, and literature support the use of omega 3 fatty acids in the acute critically ill population, more research is needed regarding omega 3 fatty acids for chronic critical illness and PICS.

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.

Multidisciplinary consensus on nutritional and metabolic therapy in enhanced recovery after abdominal surgery programs: NutRICA Project

BACKGROUND

The Enhanced Recovery After Surgery (ERAS) care pathways include evidence-based items designed to accelerate recovery after surgery. Interdisciplinarity is one of the key points of ERAS programs.

OBJECTIVE

To prepare a consensus document among the members of the Nutrition Area of the Spanish Society of Endocrinology and Nutrition (SEEN) and the Spanish Group for Multimodal Rehabilitation (GERM), in which the goal is to homogenize the nutritional and metabolic management of patients included in an ERAS program.

METHODS

69 specialists in Endocrinology and Nutrition and 85 members of the GERM participated in the project. After a literature review, 79 statements were proposed, divided into 5 sections: 17 of general characteristics, 28 referring to the preoperative period, 4 to the intraoperative, 13 to the perioperative and 17 to the postoperative period. The degree of consensus was determined through a Delphi process of 2 circulations that was ratified by a consistency analysis.

RESULTS

Overall, in 61 of the 79 statements there was a consistent agreement, with the degree of consensus being greater among members of the SEEN (64/79) than members of the GERM (59/79). Within the 18 statements where a consistent agreement was not reached, we should highlight some important nutritional strategies such as muscle mass assessment, the start of early oral feeding or pharmaconutrition.

CONCLUSION

Consensus was reached on the vast majority of the nutritional measures and care included in ERAS programs. Due to the lack of agreement on certain key points, it is necessary to continue working closely with both societies to improve the recovery of the surgical patients.

ESPEN practical guideline: Clinical nutrition in surgery

Early oral feeding is the preferred mode of nutrition for surgical patients. Avoidance of any nutritional therapy bears the risk of underfeeding during the postoperative course after major surgery. Considering that malnutrition and underfeeding are risk factors for postoperative complications, early enteral feeding is especially relevant for any surgical patient at nutritional risk, especially for those undergoing upper gastrointestinal surgery. The focus of this guideline is to cover both nutritional aspects of the Enhanced Recovery After Surgery (ERAS) concept and the special nutritional needs of patients undergoing major surgery, e.g. for cancer, and of those developing severe complications despite best perioperative care. From a metabolic and nutritional point of view, the key aspects of perioperative care include the integration of nutrition into the overall management of the patient, avoidance of long periods of preoperative fasting, re-establishment of oral feeding as early as possible after surgery, the start of nutritional therapy immediately if a nutritional risk becomes apparent, metabolic control e.g. of blood glucose, reduction of factors which exacerbate stress-related catabolism or impaired gastrointestinal function, minimized time on paralytic agents for ventilator management in the postoperative period, and early mobilization to facilitate protein synthesis and muscle function.

Multidisciplinary consensus on nutritional and metabolic therapy in enhanced recovery after abdominal surgery programs: NutRICA Project

BACKGROUND

The Enhanced Recovery After Surgery (ERAS) care pathways include evidence-based items designed to accelerate recovery after surgery. Interdisciplinarity is one of the key points of ERAS programs.

OBJECTIVE

To prepare a consensus document among the members of the Nutrition Area of the Spanish Society of Endocrinology and Nutrition (SEEN) and the Spanish Group for Multimodal Rehabilitation (GERM), in which the goal is to homogenize the nutritional and metabolic management of patients included in an ERAS program.

METHODS

69 specialists in Endocrinology and Nutrition and 85 members of the GERM participated in the project. After a literature review, 79 statements were proposed, divided into 5 sections: 17 of general characteristics, 28 referring to the preoperative period, 4 to the intraoperative, 13 to the perioperative and 17 to the postoperative period. The degree of consensus was determined through a Delphi process of 2 circulations that was ratified by a consistency analysis.

RESULTS

Overall, in 61 of the 79 statements there was a consistent agreement, with the degree of consensus being greater among members of the SEEN (64/79) than members of the GERM (59/79). Within the 18 statements where a consistent agreement was not reached, we should highlight some important nutritional strategies such as muscle mass assessment, the start of early oral feeding or pharmaconutrition.

CONCLUSION

Consensus was reached on the vast majority of the nutritional measures and care included in ERAS programs. Due to the lack of agreement on certain key points, it is necessary to continue working closely with both societies to improve the recovery of the surgical patients.

Impact of Perioperative Immunonutrition on Complications in Patients Undergoing Radical Cystectomy: A Retrospective Analysis

Introduction:

Radical cystectomy (RC) is the gold standard treatment for patients with muscle-invasive or refractory non-muscle invasive bladder cancer. It is estimated that approximately 64% and 13% of RC patients experience any complication and major complications, respectively. Specialized immunonutrition (SIM) aims to reduce the rates of complications after RC. We reported surgical complication rates in RC patients who received (SIM group) versus who did not receive (no-SIM group) perioperative SIM. Moreover, we investigated factors associated with complications after RC.

Material and Methods:

This is a retrospective cohort study of 52 patients who underwent RC between April 2016 and December 2017. Overall, 26 (50%) patients received perioperative SIM. We recorded age, gender, Charlson Comorbidity Index (CCI), body mass index (BMI), Malnutrition Universal Screening Tool (MUST) score, unintentional weight loss (UWL), SIM drinks consume, surgical approach, urinary diversion, neoadjuvant chemotherapy (NAC), use of total parenteral nutrition (TPN), final pathology, length of stay (LOS), and complications.

Results:

SIM was associated with higher rates of documented infections (P = .03). Conversely, post-operative ileus was associated with higher rates of overall infections (P = .03). Median LOS was comparable within the 2 groups. Overall, 4 (15.38%) versus 0 (0%) patients in SIM versus no-SIM group were readmitted to hospital (P = .03). Age, CCI, NAC, and TPN were not associated with complication rates.

Conclusions:

SIM is not associated with lower rates of post-operative complications in RC candidates. Moreover, higher rates of documented infections were observed in the SIM group. Patients with post-operative ileus experienced more infections. Age, CCI, NAC, and TPN were not predictive of complications.

Impact of Oral Immunonutrition on Postoperative Morbidity in Digestive Oncologic Surgery: A Nation-wide Cohort Study

OBJECTIVE

The objective of the present study was to assess the effect of preoperative immunonutrition on a nationwide scale.

BACKGROUND

According to international guidelines, immunonutrition should be prescribed before major oncologic digestive surgery to decrease postoperative morbidity. Nevertheless, this practice remains controversial.

METHODS

We used a prospective national health database named "Echantillon généraliste des Bénéficiaires." Patients were selected with ICD10 codes of cancer and digestive surgery procedures from 2012 to 2016. Two groups were identified: with reimbursement of immunonutrition 45 days before surgery (IN-group) or not (no-IN-group). Primary outcome was 90-day severe morbidity. Secondary outcomes were postoperative length of stay (LOS) and overall survival. Logistic regression and survival analysis adjusted with IPW method were performed.

RESULTS

One thousand seven hundred seventy-one patients were included. The proportion of different cancers was as follows: 72% patients were included in the colorectal group, 14% in the hepato-pancreato-biliary group, and 12% in the upper gastrointestinal group. Patients from the IN-group (n = 606, 34%) were younger (67.1 ± 11.8 vs 69.2 ± 12.2 years, P < 0.001), with increased use of other oral nutritional supplements (49.5% vs 31.8%, P < 0.001) and had more digestive anastomoses (89.4% vs 83.0%, P < 0.001). There was no significant difference between the 2 groups for 90-day severe morbidity [odds ratio (OR): 0.91, 95% confidence interval (95% CI): 0.73-1.14] or in survival (hazard ratio: 0.89, 95% CI: 0.73-1.08). LOS were shorter in the IN-group [-1.26 days, 95% CI: -2.40 to -0.10)].

CONCLUSION

The preoperative use of immunonutrition before major oncologic digestive surgery was not associated with any significant difference in morbidity or mortality. However, the LOS was significantly shorter in the IN-group.

Impact of Artificial Nutrition on Postoperative Complications

Malnutrition is common in surgical cancer patients and it is widely accepted that it can adversely affect their postoperative outcome. Assessing the nutritional status of every patient, in particular care of elderly and cancer patients, is a crucial feature of the therapeutic pathway in order to optimize every strategy. Evidence exists that the advantages of perioperative nutrition are more significant in malnourished patients submitted to major surgery. For patients recognized as malnourished, preoperative nutrition therapies are indicated; the choice between parenteral and enteral nutrition is still controversial in perioperative malnourished surgical cancer patients, although enteral nutrition seems to have the best risk–benefit ratio. Early oral nutrition after surgery is advisable, when feasible, and should be administered in all the patients undergoing elective major surgery, if compliant. In patients with high risk for postoperative infections, perioperative immunonutrition has been proved in some ways to be effective, even if operations including those for cancer have to be delayed.

Clinical Efficacy of Perioperative Immunonutrition Containing Omega-3-Fatty Acids in Patients Undergoing Hepatectomy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The effect of immunonutrition in patients undergoing hepatectomy remains unclear. This meta-analysis aimed to assess the impact of immunonutrition on postoperative clinical outcomes in patients undergoing hepatectomy.

METHODS

A literature search of PubMed, Cochrane Library, Web of Science, and Embase databases was performed to identify all randomized controlled trials (RCTs) exploring the effect of perioperative immunonutrition in patients undergoing hepatectomy until the end of March 10, 2020. Quality assessment and data extraction of RCTs were conducted independently by 3 reviewers. Mean difference (MD) and odds ratio (OR) with 95% confidence interval (CI) were calculated using a fixed-effects or random-effects model. The meta-analysis was performed with RevMan 5.3 software.

RESULTS

Nine RCTs involving a total of 966 patients were finally included. This meta-analysis showed that immunonutrition significantly reduced the incidences of overall postoperative complications (OR = 0.57, 95% CI: 0.34-0.95; p = 0.03), overall postoperative infectious complications (OR = 0.53, 95% CI: 0.37-0.75; p = 0.0003), and incision infection (OR = 0.50, 95% CI: 0.28-0.89; p = 0.02), and it shortened the length of hospital stay (MD = -3.80, 95% CI: -6.59 to -1.02; p = 0.007). There were no significant differences in the incidences of pulmonary infection (OR = 0.60, 95% CI: 0.32-1.12; p = 0.11), urinary tract infection (OR = 1.30, 95% CI: 0.55-3.08; p = 0.55), liver failure (OR = 0.54, 95% CI: 0.23-1.24; p = 0.15), and postoperative mortality (OR = 0.69, 95% CI: 0.26-1.83; p = 0.46).

CONCLUSION

Given its positive impact on postoperative complications and the tendency to shorten the length of hospital stay, perioperative immunonutrition should be encouraged in patients undergoing hepatectomy.

Expert Opinion on Benefits of Long-Chain Omega-3 Fatty Acids (DHA and EPA) in Aging and Clinical Nutrition

Life expectancy is increasing and so is the prevalence of age-related non-communicable diseases (NCDs). Consequently, older people and patients present with multi-morbidities and more complex needs, putting significant pressure on healthcare systems. Effective nutrition interventions could be an important tool to address patient needs, improve clinical outcomes and reduce healthcare costs. Inflammation plays a central role in NCDs, so targeting it is relevant to disease prevention and treatment. The long-chain omega-3 polyunsaturated fatty acids (omega-3 LCPUFAs) docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are known to reduce inflammation and promote its resolution, suggesting a beneficial role in various therapeutic areas. An expert group reviewed the data on omega-3 LCPUFAs in specific patient populations and medical conditions. Evidence for benefits in cognitive health, age- and disease-related decline in muscle mass, cancer treatment, surgical patients and critical illness was identified. Use of DHA and EPA in some conditions is already included in some relevant guidelines. However, it is important to note that data on the effects of omega-3 LCPUFAs are still inconsistent in many areas (e.g., cognitive decline) due to a range of factors that vary amongst the trials performed to date; these factors include dose, timing and duration; baseline omega-3 LCPUFA status; and intake of other nutrients. Well-designed intervention studies are required to optimize the effects of DHA and EPA in specific patient populations and to develop more personalized strategies for their use.

Long-term outcomes after perioperative treatment with omega-3 fatty acid supplements in colorectal cancer

Background

This study aimed to evaluate the effect of perioperative supplementation with omega‐3 fatty acids (n‐3 FA) on perioperative outcomes and survival in patients undergoing colorectal cancer surgery.

Methods

Patients scheduled for elective resection of colorectal cancer between 2007 and 2010 were randomized to either an n‐3 FA‐enriched oral nutrition supplement (ONS) twice daily or a standard ONS (control) for 7 days before and after surgery. Outcome measures, including postoperative complications, 3‐year cumulative incidence of local or metastatic colorectal cancer recurrence and 5‐year overall survival, were compared between the groups.

Results

Of 148 patients enrolled in the study, 125 (65 patients receiving n‐3 FA‐enriched ONS and 60 receiving standard ONS) were analysed. There were no differences in postoperative complications after surgery (P = 0·544). The risk of disease recurrence at 3 years was similar (relative risk 1·66, 95 per cent c.i. 0·65 to 4·26).The 5‐year survival rate of patients treated with n‐3 FA was 69·2 (95 per cent c.i. 56·5 to 78·9) per cent, compared with 81·7 (69·3 to 89·4) per cent in the control group (P = 0·193). After adjustment for age, stage of disease and adjuvant chemotherapy, n‐3 FA was associated with higher mortality compared with controls (hazard ratio 1·73, 95 per cent c.i. 1·06 to 2·83; P = 0·029). The interaction between n‐3 FA and adjuvant chemotherapy was not statistically significant.

Conclusion

Perioperative supplementation with n‐3 FA did not confer a survival benefit in patients undergoing colorectal cancer surgery. n‐3 FA did not benefit the subgroup of patients treated with adjuvant chemotherapy or decrease the risk of disease recurrence.

Results of a survey on peri-operative nutritional support in pancreatic and biliary surgery in Spain

Introduction: a survey on peri-operative nutritional support in pancreatic and biliary surgery among Spanish hospitals in 2007 showed that few surgical groups followed the 2006 ESPEN guidelines. Ten years later we sent a questionnaire to check the current situation. Methods: a questionnaire with 21 items sent to 38 centers, related to fasting time before and after surgery, nutritional screening use and type, time and type of peri-operative nutritional support, and number of procedures. Results: thirty-four institutions responded. The median number of pancreatic resections (head/total) was 29.5 (95% CI: 23.0-35; range, 5-68) (total, 1002); of surgeries for biliary malignancies (non-pancreatic), 9.8 (95% CI: 7.3-12.4; range, 2-30); and of main biliary resections for benign conditions, 10.4 (95% CI: 7.6-13.3; range, 2-33). Before surgery, only 41.2% of the sites used nutritional support (< 50% used any nutritional screening procedure). The mean duration of preoperative fasting for solid foods was 9.3 h (range, 6-24 h); it was 6.6 h for liquids (range, 2-12). Following pancreatic surgery, 29.4% tried to use early oral feeding, but 88.2% of the surveyed teams used some nutritional support; 26.5% of respondents used TPN in 100% of cases. Different percentages of TPN and EN were used in the other centers. In malignant biliary surgery, 22.6% used TPN always, and EN in 19.3% of cases. Conclusions: TPN is the commonest nutrition approach after pancreatic head surgery. Only 29.4% of the units used early oral feeding, and 32.3% used EN; 22.6% used TPN regularly after surgery for malignant biliary tumours. The 2006 ESPEN guideline recommendations are not regularly followed 12 years after their publication in our country.

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.

Effect of Preoperative Administration of Oral Arginine and Glutamine in Patients with Enterocutaneous Fistula Submitted to Definitive Surgery: a Prospective Randomized Trial

BACKGROUND

The use of glutamine and arginine has shown several advantages in postoperative outcomes in patients after gastrointestinal surgery. We determined the effects of its use in patients with enterocutaneous fistula after operative treatment.

PATIENTS AND METHODS

Forty patients with enterocutaneous fistula were randomly assigned to one of two groups. The control group received the standard medical care while the patients of the experimental group were supplemented with enteral administration of 4.5 g of arginine and 10 g of glutamine per day for 7 days prior to the surgery. The primary outcome variable was the recurrence of the fistula and the secondary outcomes were preoperative and postoperative serum concentrations of interleukin 6 and C-reactive protein and postoperative infectious complications.

RESULTS

Twenty patients were assigned to each group. The fistula recurred in two patients (10%) of the experimental group and in nine patients (45%) of the control group (P < 0.001). We found a total of 13 infectious complications in six patients of the control group (all with fistula recurrence) and none in the experimental group. Mean preoperative serum concentrations of interleukin 6 and C-reactive protein were lower in patients from the experimental group. In addition, these levels were lower in patients who had recurrence if compared to patients that did not recur.

CONCLUSION

Preoperative administration of oral arginine and glutamine could be valuable in the postoperative recovery of patients with enterocutaneous fistulas submitted to definitive surgery.

The relation between Malnutrition Universal Screening Tool (MUST), computed tomography-derived body composition, systemic inflammation, and clinical outcomes in patients undergoing surgery for colorectal cancer

BACKGROUND

Nutritional status is an important factor affecting a patient's clinical outcomes. Early identification of patients who are at risk of malnutrition is important to improve clinical outcomes and reduce health cost. The Malnutrition Universal Screening Tool (MUST) has been recommended as part of the routine nursing assessment for all patients at hospital admission.

OBJECTIVE

The aim of this study was to examine the association between nutritional status (MUST), systemic inflammatory response (SIR), body composition, and clinical outcomes in patients undergoing surgery for colorectal cancer.

METHODS

The malnutrition risk was examined using MUST in patients admitted for surgery for colorectal cancer between March 2013 and June 2016. Preoperative computed tomography scans were used to define the body composition. The presence of SIR was evidenced by the modified Glasgow prognostic score and the neutrophil to lymphocyte ratio. Postoperative complications, severity of complication, length of hospital stay, and mortality were considered as outcome measures.

RESULTS

The study included 363 patients (199 males, 164 females); 21% of the patients presented with a medium or high nutritional risk. There were significant associations between MUST and subcutaneous adiposity (P < 0.001), visceral obesity (P < 0.001), and low skeletal muscle index (P < 0.001). No statistically significant association was identified between MUST score and presence of any complication or severity of complication. On multivariate analysis, MUST remained independently associated with the length of hospital stay (OR: 2.17; 95% CI: 1.45, 3.26; P < 0.001). Kaplan-Meier survival curves showed an increased number of deaths for patients at medium or high risk of malnutrition (P < 0.001). This association was found to be independent of other confounding factors (HR: 1.45; 95% CI: 1.06, 1.99; P = 0.020).

CONCLUSIONS

MUST score is an independent marker of risk in those undergoing surgery for colorectal cancer and should remain a key part of preoperative assessment.

Prehabilitation: how to prepare our patients for elective major abdominal surgeries?

Surgical approach is the main form of treatment for several diseases of the abdominal cavity. However, surgical procedure itself is a stressor that may lead to adverse effects unrelated to the treatment goal. Prehabilitation has emerged as a multifactorial preoperative health conditioning program, which promotes improvement in functional capacity and postoperative evolution. The present study reviews literature using MEDLINE, Ovid, Google Scholar, and Cochrane databases in order to determine the concept of prehabilitation program and the indications and means of patient selection for it, as well as to suggest ways to implement this program in cases of major abdominal surgeries.

Effects of a diet enriched with eicosapentaenoic, docosahexaenoic and glutamine on cytokines as immunological markers for systemic inflammation in bitches before and after ovariohysterectomy

The post-operative period can generate immunological stress and can be modulated through supplementation with the omega-3 series of polyunsaturated fatty acids. This study aimed to evaluate the effects of diets enriched with high doses of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids and glutamine on inflammatory mediators in dogs before and after ovariohysterectomy (OVH). Twelve female dogs were divided into two groups: group A was fed a commercial diet without the addition of EPA and DHA, and group B was fed an experimental diet enriched with EPA and DHA (0.2 g/100 kcal). Experimental diet intake initiated 21 days before surgery and continued until 30 days after OVH. Parameters measured were serum cytokines (TNF-α, IL-6 and IL-10), C-reactive protein (CRP), IGF-1, lymphoproliferation and body composition before and after surgery. Statistical analyses were performed with SAS software considering the effects of age and diet and their interactions, and means were compared by the Tukey test. There was no difference between groups in body weight (p = .682), lean mass (p = .101) and body fat (p = .103). There were no group differences in serum concentrations of TNF-α, IL-6, IL-10, IGF-1, CRP and the percentage of lymphocyte proliferation. However, a time effect for TNF-α was observed (p < .001), in which T_0P (10 days after the surgical procedure) presented lower values of this cytokine when compared to the other evaluation time points; and interaction effects between group and time were observed for serum concentrations of IL-6 (p < .001) and IL-10 (p = .002). OVH procedure was not considered invasive enough to increase inflammatory cytokines after 30 days of surgery, as well as the dosage of the EPA and DHA used before and after the surgery did not modulate the inflammatory markers.

Postoperative complication rate and survival of patients with gastric cancer undergoing immunonutrition: A retrospective study

OBJECTIVES

This study aimed to evaluate the effect of preoperative immunonutrition on the rate of postoperative complication and survival of patients with gastric cancer.

METHODS

A retrospective cohort was formed after data collection of patients hospitalized with gastric cancer. Postoperative complications classified according to the Clavien-Dindo classification system, length of hospital stay, readmissions, and rates of survival at 6 mo, 1 y, and 5 y were analyzed. A χ² or Fisher's exact test, Student or Mann-Whitney t test, and Kaplan-Meier and Cox regressions were used in the statistical analysis.

RESULTS

A total of 164 patients were included in the study, with 56 patients assigned to the immunonutrition group and 108 to the conventional group. There were no significant differences in postoperative complications between the immunonutrition and conventional groups (51.8% versus 58.3%; P = 0.423). The most frequent complications were fistula and surgical wound infection. Length of hospital stay did not differ between the groups (median of 7.0 d: P = 0.615) and the presence of readmissions did not differ either (12.5% versus 15.7%; P = 0.648). In the multivariate Cox regression, in a pooled model for group, age, sex, body mass index, Charlson comorbidity index, staging, neoadjuvant chemotherapy, and type of surgery, there was a significant difference in survival rates at 6 mo (P = 0.011), 1 y (P = 0.006), and 5 y (P < 0.001).

CONCLUSIONS

Preoperative immunonutrition in patients with gastric cancer did not reduce postoperative complications or length of hospital stay. More studies are needed to confirm the benefit of immunonutriton supplementation for overall survival when associated with other protective factors.

The Impact of Preoperative Immunonutrition and Standard Polymeric Supplements on Patient Outcomes After Pelvic Exenteration Surgery, Taking Compliance Into Consideration: A Randomized Controlled Trial

BACKGROUND

The effect of immunonutrition vs standard polymeric nutrition in the preoperative phase on patient outcomes is still unclear, which could be due to contributing factors such as poorly reported compliance and unequal provision of protein, energy, and volume. The aim of this study was to examine the effects of preoperative immunonutrition compared with standard polymeric supplements matched for energy, protein, volume, length of stay, and postoperative complications in pelvic exenteration surgery, taking into consideration compliance.

METHODS

This was a single-blinded, randomized, controlled trial in patients undergoing pelvic exenteration surgery. Fifty-two participants were randomly assigned to consume 3 immunonutrition supplements/d for 5 days preoperatively, and 56 participants were randomly assigned to consume 3 standard polymeric supplements/d for 5 days preoperatively. Primary and secondary outcome measures were assessed. Compliance with each nutrition regime was recorded during the intervention, and subanalysis was conducted.

RESULTS

There was no significant difference between immunonutrition and standard polymeric supplements on length of stay (P = 0.988) or postoperative complications (P = 0.179) after pelvic exenteration surgery. Compliance with nutrition supplements was significantly less in malnourished (n = 33) compared with well-nourished participants (n = 74) (P = 0.016). Compliance varied between study groups, although not significant.

CONCLUSION

Preoperative immunonutrition did not significantly impact length of stay or postoperative complications compared with standard polymeric supplements after pelvic exenteration surgery, despite controlling for protein, energy, and volume. Compliance, protein, and energy may considerably impact the effect of immunonutrition, particularly in malnourished patients.

Pre-Operative vs. Peri-Operative Nutrition Supplementation in Hepatic Resection for Cancer: A Systematic Review

Despite improvements in safety of hepatic resection post-operative complications occur in up to a half of patients. A systematic review was undertaken to compare the effect of pre-operative and peri-operative nutritional supplementation on post-operative outcomes in patients undergoing hepatic resection for malignancy. Included studies were identified through a search of PubMed (1966 to November 2016), Embase (1947 to November 2016) and the Cochrane Library (1993 to November 2016). Eleven studies involving a total of 725 patients were included in this systematic review. BCAA supplementation in the pre-operative and peri-operative period was reported to reduce the overall complication rate by 26.9% (P = 0.01) in one cohort study while pre-operative immunonutrition was shown to reduce post-operative ascites by 25.4% (P =0.012) in another cohort study without affecting the overall complication rate. Four further studies on enteral supplementation failed to show a benefit with regards to post-operative complications. Post-operative mortality was unaffected by pre-operative and peri-operative BCAA. Both pre-operative and peri-operative nutritional supplementation have shown promising results regarding the post-operative course of patients undergoing hepatic resection for malignancy. No randomized controlled study exists directly comparing pre-operative and peri-operative nutrition and this needs to be focused on in future research.

Immunonutrition in Critical Illness: What Is the Role?

Acute illness-associated malnutrition leads to muscle wasting, delayed wound healing, failure to wean from ventilator support, and possibly higher rates of infection and longer hospital stays unless appropriate metabolic support is provided in the form of nutrition therapy. Agreement is still lacking about the value of individual immune-modulating substrates for specific patient populations. However, it has long been agreed that there are 3 primary targets for these substrates: 1) mucosal barrier function, 2) cellular defense function, and 3) local and systemic inflammation. These targets guide the multitude of interventions necessary to stabilize and treat the hypercatabolic intensive care unit patient, including specialized nutrition therapy. The paradigm shift that occurred 30 years ago created a unique role for nutrition as an agent to support host defense mechanisms and prevent infectious complications in the critically ill patient. This overview of immunonutrition will discuss the evidence for its role in critical illness today.

Impact of Enteral Nutrition with an Immunomodulating Diet Enriched with Hydrolyzed Whey Peptide on Infection After Liver Transplantation

BACKGROUND

Infection is a leading cause of death after liver transplantation (LT). Therefore, prevention of infection is crucial for improving outcomes after LT. We examined the impact of early enteral nutrition with an immunomodulating diet (IMD) enriched with hydrolyzed whey peptide (HWP) formulation on infection after living donor LT (LDLT), focusing on sarcopenia.

METHODS

This study enrolled 279 consecutive patients who underwent primary LDLT at our institute between January 2008 and April 2015. Early enteral nutrition with the IMD enriched with HWP formulation and a conventional elemental diet were started within the first 24 h after surgery for 164 (IMD-HWP) and 115 (conventional) patients. Sequential changes in nutritional parameters, and the incidences of acute cellular rejection (ACR) and bacteremia were compared between the IMD-HWP and control groups. The comparison was made between those members of each group that did or did not exhibit sarcopenia. Risk factors for post-transplant bacteremia were also assessed.

RESULTS

Postoperative nutritional parameters and the incidence of ACR were comparable between the groups, except for the prealbumin level. The incidence of bacteremia was significantly lower in the IMD-HWP group, and among patients without sarcopenia in the IMD-HWP group compared with the conventional group (24.4 vs. 41.7%; P = 0.002 and 20.8 vs. 39.0%; P = 0.040, respectively). Independent risk factor for bacteremia comprised bleeding ≥10,000 mL (P = 0.025). In contrast, enteral nutrition without HWP formulation was not significantly associated with bacteremia. However, enteral nutrition without HWP formulation (P = 0.080), MELD scores (P = 0.097), and ABO incompatibility (P = 0.088) showed a trend toward increased incidence of bacteremia, although they did not reach statistical significance in the multivariate analysis.

CONCLUSION

Postoperative immunonutrition with an IMD enriched with HWP formulation was closely involved with post-transplant bacteremia.

Immunonutrition for patients undergoing surgery for head and neck cancer

BACKGROUND

Patients with head and neck cancer are often malnourished. Surgery for such cancers is complex and may be undertaken after a course of radiotherapy. As a result, patients may have postoperative complications such as fistulae and wound infections, as well as more generalised infections such as pneumonia. One possible way to enhance recovery, and reduce the incidence of these complications, is by improving nutrition. Nutritional formulas that deliver basic nutrients as well as amino acids (arginine and glutamine), ribonucleic acid (RNA) and/or lipids (omega-3 fatty acids) are known as immunonutrition.

OBJECTIVES

To assess the effects of immunonutrition treatment, compared to standard feeding, on postoperative recovery in adult patients undergoing elective (non-emergency) surgery for head and neck cancer.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL); PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 February 2018.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing immunonutrition given either preoperatively, postoperatively or perioperatively to adult patients (18 years of age or older) undergoing an elective surgical procedure for head and neck cancer, compared with a control group receiving either standard polymeric nutritional supplements or no supplements.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. The primary outcomes were: length of hospital stay (days), wound infection, fistula formation and adverse events/tolerance of feeds, as defined by trial authors. Secondary outcomes were: all-cause mortality and postoperative complications (as defined by trial authors). We used GRADE to assess the quality of the evidence for each outcome; this is indicated in italics.

MAIN RESULTS

We included 19 RCTs (1099 participants). The mean age of participants ranged from 47 to 66 years. Most studies (12/19) had fewer than 25 patients in each treatment group. Most studies (16/19) used immunonutrition formulas containing arginine, but there was variation in the actual products and amounts used, and in the length of intervention postoperatively. Follow-up time for outcome measurement varied considerably across studies, ranging from five days to greater than or equal to 16 months.Primary outcomesWe found no evidence of a difference in the length of hospital stay (mean difference -2.5 days, 95% confidence interval (CI) -5.11 to 0.12; 10 studies, 757 participants; low-quality evidence). Similarly, we found no evidence of an effect of immunonutrition on wound infection (risk ratio (RR) 0.94, 95% CI 0.70 to 1.26; 12 studies, 812 participants; very low-quality evidence). Fistula formation may be reduced with immunonutrition; the absolute risks were 11.3% and 5.4% in the standard care and immunonutrition groups, with a RR of 0.48 (95% CI 0.27 to 0.85; 10 studies, 747 participants; low-quality evidence). We found no evidence of a difference in terms of tolerance of feeds ('adverse events') between treatments (RR 1.33, 95% CI 0.86 to 2.06; 9 studies, 719 participants; very low-quality evidence).Secondary outcomesWe found no evidence of a difference between treatments in all-cause mortality (RR 1.33, 95% CI 0.48 to 3.66; 14 studies, 776 participants; low-quality evidence). Other postoperative complications such as pneumonia and urinary tract infections were not commonly reported.

AUTHORS' CONCLUSIONS

The risk of postoperative fistula formation may be reduced with immunonutrition, but we found no evidence of an effect of immunonutrition on any of the other outcomes that we assessed. The studies included in this review were generally small or at high risk of bias (or both). We judged the overall quality of the evidence to be low for the outcomes length of hospital stay and all-cause mortality, and very low for wound infection and adverse events. Further research should include larger, better quality studies.

Pharmaconutrition administration on outcomes of elective oncological surgery for gastrointestinal malignancies: is timing everything?-a review of published meta-analyses until the end of 2016

The last 25 years have seen an increasing number of publications attesting the benefits of pharmaconutrition in the management of patients undergoing elective oncological gastrointestinal surgery. A number of randomized controlled trials and meta-analyses suggest the use of pharmaconutrition in this group of patients produces superior outcomes to standard nutritional formulations in terms of postoperative infective complications, anastomotic breakdown and length of hospital stay. The use of pharmaconutrition products, therefore, has gained increasing acceptance for use in elective gastrointestinal oncological surgical populations and been incorporated into practice guidelines. However, there remains doubts as to the robustness of such data supporting these recommendation. This is because studies reporting improved outcomes with pharmaconutrition (I) frequently compare this intervention with non-equivalent control groups; (II) do not report on the actual nutritional provision received by study participants; (III) overlook the potential impact of industry funding on research conducted and (IV) do not adopt a multi-disciplinary approach to the research undertaken. For these reasons, a critical re-appraisal of the use and recommendations of pharmaconutrition in this group of patients is urgently warranted to resolve some of the above mentioned issues. The aim of this review was to analyse meta-analyses published until the end of 2016 in this area to highlight the strengths and weakness of the present research and prioritize certain areas which will benefit from future research.

Current perspective for tube feeding in the elderly: from identifying malnutrition to providing of enteral nutrition

With the number of individuals older than 65 years expected to rise significantly over the next few decades, dramatic changes to our society and health care system will need to take place to meet their needs. Age-related changes in muscle mass and body composition along with medical comorbidities including stroke, dementia, and depression place elderly adults at high risk for developing malnutrition and frailty. This loss of function and decline in muscle mass (ie, sarcopenia) can be associated with reduced mobility and ability to perform the task of daily living, placing the elderly at an increased risk for falls, fractures, and subsequent institutionalization, leading to a decline in the quality of life and increased mortality. There are a number of modifiable factors that can mitigate some of the muscle loss elderly experience especially when hospitalized. Due to this, it is paramount for providers to understand the pathophysiology behind malnutrition and sarcopenia, be able to assess risk factors for malnutrition, and provide appropriate nutrition support. The present review describes the pathophysiology of malnutrition, identifies contributing factors to this condition, discusses tools to assess nutritional status, and proposes key strategies for optimizing enteral nutrition therapy for the elderly.

Perioperative Nutritional Optimization in Spine Surgery

Nutritional optimization in patients undergoing spine surgery is important as improved surgical outcomes and decreased rates of complications have been noted in optimized patients. With the increasingly high numbers of elderly patient and patients with metabolic comorbidities undergoing spine procedures, perioperative nutritional status should be enhanced for the best possible surgical outcomes. Methods of optimization include preoperative screening with Nutritional Risk Score or other scoring systems, looking for changes in body mass index, detecting sarcopenia, and screening for metabolic abnormalities. Assessment of blood glucose, electrolytes, cholesterol, vitamin levels, visceral proteins, and lean body mass must be done preoperatively and close monitoring should be continued postoperatively. Albumin helps to determine the health status of patients before surgery and prealbumin as a predictor of surgical outcomes is being investigated. Malnourished patients should be given balanced diets replenishing key nutrient deficits, glucose should be maintained with sliding scale insulin or continuous infusions and immunonutrition may be implemented. Postoperatively, patients should initiate a diet as soon as possible to decrease overall length of stay and complication rates, facilitating return to normal activities.

Nutritional Therapy in Gastrointestinal Cancers

Malnutrition is the most frequent nutritional disorder in patients with gastrointestinal cancer and is associated with cachexia syndrome, worsening of prognosis, and shortened survival rate. Early nutrition screening, assessment, and intervention are able to favorably modify the clinical evolution of affected patients. The adequate provision of nutritional requirements has been associated with improvement of immunologic status, and avoidance of further complications related to poor nutritional status, surgical treatment, and anticancer therapy. In malnourished patients, the supplementation of perioperative immunonutrition might contribute to fewer infectious and noninfectious complications, shorter length of hospitalization, and improved wound healing.