The anabolic effect of perioperative nutrition depends on the patient's catabolic state before surgery

The effects of elective abdominal surgery on protein turnover: A meta-analysis of stable isotope techniques to investigate postoperative catabolism

BACKGROUND & AIMS

Elective surgery induces skeletal muscle wasting driven by an imbalance between muscle protein synthesis and breakdown. From examination of diverse stable isotope tracer techniques, the dynamic processes driving this imbalance are unclear. This meta-analysis aimed to elucidate the mechanistic driver(s) of postoperative protein catabolism through stable isotope assessment of protein turnover before and after abdominal surgery.

METHODS

Meta-analysis was performed of randomized controlled trials and cohort studies in patients undergoing elective abdominal surgery that contained measurements of whole-body or skeletal muscle protein turnover using stable isotope tracer methodologies pre- and postoperatively. Postoperative changes in protein synthesis and breakdown were assessed through subgroup analysis of tracer methodology and perioperative care.

RESULTS

Surgery elicited no overall change in protein synthesis [standardized mean difference (SMD) -0.47, 95% confidence interval (CI): -1.32, 0.39, p = 0.25]. However, subgroup analysis revealed significant suppressions via direct-incorporation methodology [SMD -1.53, 95%CI: -2.89, -0.17, p = 0.03] within skeletal muscle. Changes of this nature were not present among arterio-venous [SMD 0.61, 95%CI: -1.48, 2.70, p = 0.58] or end-product [SMD -0.09, 95%CI: -0.81, 0.64, p = 0.82] whole-body measures. Surgery resulted in no overall change in protein breakdown [SMD 0.63, 95%CI: -0.06, 1.32, p = 0.07]. Yet, separation by tracer methodology illustrated significant increases in urinary end-products (urea/ammonia) [SMD 0.70, 95%CI: 0.38, 1.02, p < 0.001] that were not present among arterio-venous measures [SMD 0.67, 95%CI: -1.05, 2.38, p = 0.45].

CONCLUSIONS

Elective abdominal surgery elicits suppressions in skeletal muscle protein synthesis that are not reflected on a whole-body level. Lack of uniform changes across whole-body tracer techniques are likely due to contribution from tissues other than skeletal muscle.

Current Landscape of Nutrition Within Prehabilitation Oncology Research: A Scoping Review

Background: Prehabilitation aims to improve functional capacity prior to cancer treatment to achieve better psychosocial and clinical outcomes. Prehabilitation interventions vary considerably in design and delivery. In order to identify gaps in knowledge and facilitate the design of future studies, we undertook a scoping review of prehabilitation studies to map the range of work on prehabilitation being carried out in any cancer type and with a particular focus on diet or nutrition interventions. Objectives: Firstly, to describe the type of prehabilitation programs currently being conducted. Secondly, to describe the extent to which prehabilitation studies involved aspects of nutrition, including assessment, interventions, implementation, and outcomes. Eligibility Criteria: Any study of quantitative or qualitative design that employed a formal prehabilitation program before cancer treatment ("prehabilitation" listed in keywords, title, or abstract). Sources of Evidence: Search was conducted in July 2020 using MEDLINE, PubMed, EMBASE, EMCARE, CINAHL, and AMED. Charting Methods: Quantitative data were reported as frequencies. Qualitative nutrition data were charted using a framework analysis that reflects the Nutrition Care Process Model: assessment, intervention, and monitoring/evaluation of the nutrition intervention. Results: Five hundred fifty unique articles were identified: 110 studies met inclusion criteria of a formal prehabilitation study in oncology. prehabilitation studies were mostly cohort studies (41%) or randomized-controlled trials (38%) of multimodal (49%), or exercise-only (44%) interventions that were applied before surgery (94%). Nutrition assessment was inconsistently applied across these studies, and often conducted without validated tools (46%). Of the 110 studies, 37 (34%) included a nutrition treatment component. Half of these studies provided the goal for the nutrition component of their prehabilitation program; of these goals, less than half referenced accepted nutrition guidelines in surgery or oncology. Nutrition interventions largely consisted of counseling with dietary supplementation. The nutrition intervention was indiscernible in 24% of studies. Two-thirds of studies did not monitor the nutrition intervention nor evaluate nutrition outcomes. Conclusion: Prehabilitation literature lacks standardized and validated nutritional assessment, is frequently conducted without evidence-based nutrition interventions, and is typically implemented without monitoring the nutrition intervention or evaluating the intervention's contribution to outcomes. We suggest that the development of a core outcome set could improve the quality of the studies, enable pooling of evidence, and address some of the research gaps identified.

Prolonged preoperative fasting induces postoperative insulin resistance by ER-stress mediated Glut4 down-regulation in skeletal muscles

Preoperative fasting aims to prevent pulmonary aspiration and improve bowel preparation, but it may induce profound systemic catabolic responses that lead to protein breakdown and insulin-resistant hyperglycemia after operation. However, the molecular mechanisms of catabolic reaction induced by prolonged preoperative fasting and surgical stress are undetermined. In this study, anesthetized rats were randomly assigned to receive a sham operation or laparotomy cecectomy. Fasting groups were restricted from food and water for 12 h before operation, while the feeding group had free access to food throughout the study period. Twenty-four hours after operation, the animals were sacrificed to collect blood samples and soleus muscles for analysis. Postoperative blood glucose level was significantly increased in the fasting group with elevated serum insulin and C-peptide. Continuous feeding reduced serum myoglobin and lactate dehydrogenase concentrations. Preoperative fasting activated inositol-requiring transmembrane kinase/endoribonuclease (IRE)-1α and c-Jun N-terminal kinase (JNK) mediated endoplasmic reticulum (ER)-stress, and reduced glucose transporter type 4 (Glut4) expression in the soleus muscle. Phospholamban phosphorylation was reduced and intracellular calcium levels were increased in the isolated skeletal muscle cells. Similar results were found in ER stress-induced C1C12 myoblasts. The expression of Glut4 was suppressed in the stressed C1C12, but was potentiated following inhibition of ER stress and chelation of intracellular free calcium. This study provides evidence demonstrating that prolonged preoperative fasting induces ER stress and generates insulin resistance in the skeletal muscle through suppression of Glut4 and inactivation of Ca²⁺-ATPase, leading to intracellular calcium homeostasis disruption and peripheral insulin resistance.

Third-Variable Effects: Tools to Understand Who, When, Why, and How Patients Benefit From Surgical Prehabilitation

Prehabilitation is a new field of research that aims to optimize modifiable surgical risk factors before surgery to improve patient-oriented outcomes preoperatively and postoperatively. As with any new intervention, the pressing questions that arise include what interventions work, for whom they work, and when do they work best? Given that prehabilitation can be resource intensive, and that preoperative patient characteristics are likely to produce variation in response to treatment, establishing answers to these questions is critical for successful implementation of prehabilitation in clinical practice. The objective of this review article is to describe the illuminating potential of including "third-variable effects" into the integration of research design; by planning for and including measurements of mediators, moderators, and confounders in the design and analysis of prehabilitation research, we can begin to answer practical, clinically relevant questions.

Prognostic value of Mini Nutritional Assessment-Short Form with aortic valve stenosis following transcatheter aortic valve implantation

Aims

Older adults at risk for malnutrition are known to have a high mortality rate. This study aimed to investigate whether the Mini Nutritional Assessment—Short Form (MNA‐SF) could predict midterm mortality in patients undergoing transcatheter aortic valve implantation (TAVI).

Methods and results

We applied the MNA‐SF in 288 patients who had undergone TAVI from January 2016 to June 2019 at the St. Marianna University School of Medicine hospital. Using the MNA‐SF cut‐off value to indicate the risk of malnutrition, patients were divided into two groups, namely, those with an MNA‐SF score ≤11 (impaired MNA‐SF group) and those with an MNA‐SF score ≥12 (maintained MNA‐SF group). We used this value to investigate the association between the MNA‐SF and all‐cause mortality. Overall, 188 (65%) and 100 (35%) patients comprised the impaired MNA‐SF and maintained MNA‐SF groups, respectively, and 41 patients died after TAVI (mean follow‐up duration, 458 ± 315 days). Kaplan–Meier analyses showed that patients in the impaired MNA‐SF group had a significantly higher incidence of all‐cause mortality (hazard ratio 2.67; 95% confidence interval 1.29–6.21; P = 0.01). Multivariate Cox regression analyses showed that the MNA‐SF score was an independent predictor of all‐cause mortality after adjusting for the Society of Thoracic Surgeons risk score, Katz Index, and brain natriuretic peptide test results (hazard ratio 1.14; 95% confidence interval 1.01–1.28; P = 0.04).

Conclusions

The MNA‐SF was useful to screen for the risk of malnutrition in patients with TAVI and in predicting midterm prognoses in patients undergoing TAVI and could predict patient mortality after the procedure.

Effect of Obesity on the Development, Management, and Outcomes of Spinal Disorders

Obesity is a major public health issue in the United States, and rates of obesity continue to increase across the population. The association of obesity with degenerative spinal pathology underlies the observation that a substantial number of patients undergoing spine surgery are either overweight or obese. Obesity is a notable independent risk factor for both surgical and medical complications in the perioperative period and an important consideration in preoperative planning, intraoperative strategies, and postoperative management. Despite these increased risks, surgery in obese patients for a variety of degenerative conditions results in improvement in outcomes. Although obese patients may undergo gains that are absolutely lower than their nonobese counterparts, they still experience a positive treatment effect with surgery appropriate for their condition. An evidence-based approach to both preoperative and perioperative management of patients with obesity is not well established. The purpose of this article is to review the effect of obesity on the development, management, and outcomes of patients with spinal disorders and to provide data that may guide an evidence-based approach to care in this expanding patient population.

Effects of Nutritional Prehabilitation, With and Without Exercise, on Outcomes of Patients Who Undergo Colorectal Surgery: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Although there have been meta-analyses of the effects of exercise-only prehabilitation on patients undergoing colorectal surgery, little is known about the effects of nutrition-only (oral nutritional supplements with and without counseling) and multimodal (oral nutritional supplements with and without counseling and with exercise) prehabilitation on clinical outcomes and patient function after surgery. We performed a systemic review and meta-analysis to determine the individual and combined effects of nutrition-only and multimodal prehabilitation compared with no prehabilitation (control) on outcomes of patients undergoing colorectal resection.

METHODS

We searched Medline, EMBASE, CINAHL, CENTRAL, and ProQuest for cohort and randomized controlled studies of adults awaiting colorectal surgery who received at least 7 days of nutrition prehabilitation with or without exercise. We performed a random-effects meta-analysis to estimate the pooled risk ratio for categorical data and the weighted mean difference for continuous variables. The primary outcome was length of hospital stay; the secondary outcome was recovery of functional capacity based on results of a 6-minute walk test.

RESULTS

We identified 9 studies (5 randomized controlled studies and 4 cohort studies) composed of 914 patients undergoing colorectal surgery (438 received prehabilitation and 476 served as controls). Receipt of any prehabilitation significantly decreased days spent in the hospital compared with controls (weighted mean difference of length of hospital stay = -2.2 days; 95% confidence interval = -3.5 to -0.9). Only 3 studies reported on functional outcomes but could not be pooled owing to methodologic heterogeneity. In the individual studies, multimodal prehabilitation significantly improved results of the 6-minute walk test at 4 and 8 weeks after surgery compared with standard Enhanced Recovery Pathway care and at 8 weeks compared with standard Enhanced Recovery Pathway care with added rehabilitation. The 4 observational studies had a high risk of bias.

CONCLUSIONS

In a systematic review and meta-analysis, we found that nutritional prehabilitation alone or combined with an exercise program significantly decreased length of hospital stay by 2 days in patients undergoing colorectal surgery. There is some evidence that multimodal prehabilitation accelerated the return to presurgical functional capacity.

Presence of early stage cancer does not impair the early protein metabolic response to major surgery

BACKGROUND

Combined bilateral mastectomy and reconstruction is a common major surgical procedure in women with breast cancer and in those with a family history of breast cancer. As this large surgical procedure induces muscle protein loss, a preserved anabolic response to nutrition is warranted for optimal recovery. It is unclear whether the presence of early stage cancer negatively affects the protein metabolic response to major surgery as this would mandate perioperative nutritional support.

METHODS

In nine women with early stage (Stage II) breast malignancy and nine healthy women with a genetic predisposition to breast cancer undergoing the same large surgical procedure, we examined whether surgery influences the catabolic response to overnight fasting and the anabolic response to nutrition differently. Prior to and within 24 h after combined bilateral mastectomy and reconstruction surgery, whole body protein synthesis and breakdown rates were assessed after overnight fasting and after meal intake by stable isotope methodology to enable the calculation of net protein catabolism in the post-absorptive state and net protein anabolic response to a meal.

RESULTS

Major surgery resulted in an up-regulation of post-absorptive protein synthesis and breakdown rates (P < 0.001) and lower net protein catabolism (P < 0.05) and was associated with insulin resistance and increased systemic inflammation (P < 0.01). Net anabolic response to the meal was reduced after surgery (P < 0.05) but higher in cancer (P < 0.05) indicative of a more preserved meal efficiency. The significant relationship between net protein anabolism and the amount of amino acids available in the circulation (R²  = 0.85, P < 0.001) was independent of the presence of non-cachectic early stage breast cancer or surgery.

CONCLUSIONS

The presence of early stage breast cancer does not enhance the normal catabolic response to major surgery or further attenuates the anabolic response to meal intake within 24 h after major surgery in patients with non-cachectic breast cancer. This indicates that the acute anabolic potential to conventional feeding is maintained in non-cachectic early stage breast cancer after major surgery.

Morbid Obesity and Total Knee Arthroplasty: A Growing Problem

Obesity is an epidemic, with approximately 35% of the US population affected. This rate is unlikely to decline and may increase the demand for total knee arthroplasty (TKA). Data regarding the risks, benefits, and potential complications of TKA in this patient population are conflicting. Preoperative considerations are optimization of nutritional status, safe weight loss strategies, and bariatric surgery. Intraoperative concerns unique to this population include inadequate exposure, implant alignment, and durable implant fixation; postoperative issues include tibial loosening, wound complications, cardiovascular events, and respiratory complications. A thorough understanding of the medical and surgical complications associated with TKA in the obese patient will facilitate research efforts and improve outcomes.

Proceedings of the 2016 Clinical Nutrition Week Research Workshop-The Optimal Dose of Protein Provided to Critically Ill Patients

Recent literature has created considerable confusion about the optimal amount of protein/amino acids that should be provided to the critically ill patient. In fact, the evidentiary basis that directly tries to answer this question is relatively small. As a clinical nutrition research community, there is an urgent need to develop the optimal methods to assess the impact of exogenous protein/amino acid administration in the intensive care unit setting. That assessment can be conducted at various levels: (1) impact on stress response pathways, (2) impact on muscle synthesis and protein balance, (3) impact on muscle mass and function, and (4) impact on the patient's recovery. The objective of this research workshop was to review current literature relating to protein/amino acid administration for the critically ill patient and clinical outcomes and to discuss the key measurement and methodological features of future studies that should be done to inform the optimal protein/amino acid dose provided to critically ill patients.

Protein anabolic resistance in cancer: does it really exist?

PURPOSE OF REVIEW

Preventing unintentional weight and muscle loss is of crucial importance to maintain the condition and well-being of patients with cancer, improve treatment response and tolerance, and prolong survival. Anabolic resistance might explain why some cancer patients do not respond to nutritional intervention, but does recent evidence actually support this? We will discuss recent literature that casts doubt on attenuated anabolic potential in cancer.

RECENT FINDINGS

Although anabolic resistance was observed in the past, more recent studies have shown that advanced cancer patients have an anabolic potential after intake of high-quality proteins. Furthermore, a consistent linear relationship is observed in cancer between (essential) amino acid availability from the diet and net protein gain. The studied cancer patients, however, were often characterized by a normal or obese body weight, following the trend in the general population, and mild systemic inflammation. Factors like recent chemotherapy, surgery, or cachexia do not seem to attenuate the anabolic potential to feeding.

SUMMARY

Cancer patients have a normal anabolic potential which relates to the amount of essential amino acids in the meal. It remains to be determined if this is also the case in weak cancer patients with a short life expectancy and high systemic inflammation.

Promoting Perioperative Metabolic and Nutritional Care

Surgery represents a major stressor that disrupts homeostasis and can lead to loss of body cell mass. Integrated, multidisciplinary medical strategies, including enhanced recovery programs and perioperative nutrition support, can mitigate the surgically induced metabolic response, promoting optimal patient recovery following major surgery. Clinical therapies should identify those who are poorly nourished before surgery and aim to attenuate catabolism while preserving the processes that promote recovery and immunoprotection after surgery. This review will address the impact of surgery on intermediary metabolism and describe the clinical consequences that ensue. It will also focus on the role of perioperative nutrition, including preoperative nutrition risk, carbohydrate loading, and early initiation of oral feeding (centered on macronutrients) in modulating surgical stress, as well as highlight the contribution of the anesthesiologist to nutritional care. Emerging therapeutic concepts such as preoperative glycemic control and prehabilitation will be discussed.

Combining nutrition and exercise to optimize survival and recovery from critical illness: Conceptual and methodological issues

Survivors of critical illness commonly experience neuromuscular abnormalities, including muscle weakness known as ICU-acquired weakness (ICU-AW). ICU-AW is associated with delayed weaning from mechanical ventilation, extended ICU and hospital stays, more healthcare-related hospital costs, a higher risk of death, and impaired physical functioning and quality of life in the months after ICU admission. These observations speak to the importance of developing new strategies to aid in the physical recovery of acute respiratory failure patients. We posit that to maintain optimal muscle mass, strength and physical function, the combination of nutrition and exercise may have the greatest impact on physical recovery of survivors of critical illness. Randomized trials testing this and related hypotheses are needed. We discussed key methodological issues and proposed a common evaluation framework to stimulate work in this area and standardize our approach to outcome assessments across future studies.

Advances in clinical nutrition in GI surgery

This review addresses recent relevant advances to clinical nutrition regarding gastrointestinal disease surgery. Medline Ovid, EMBASE and Central were searched systematically in April 2014. Inclusion criteria were randomized controlled trials, non-randomized controlled trials and observational studies evaluating nutritional support in gastrointestinal surgery published within 5 years. The review included 56 relevant studies. Themes were: nutrition screening and risk factors predict outcome; preoperative nutritional support; shortening fasting periods and including carbohydrate solutions; early nutrition after surgery; immune modulating nutrition; synbiotics, growth hormone, omega-3 and oral, enteral and parenteral nutrition in combination. Screening for nutritional risk is profound, with special focus on dietary intake in the past week. Age and severity of disease need to be included in the screening system. Patients at severe nutritional risk benefit from nutritional therapy before surgery. New standards are developing quickly and clinical guidelines on surgery should include updated knowledge within clinical nutrition.

Perioperative catabolism

PURPOSE

This article reviews the pathophysiology, clinical relevance, and therapy of the catabolic response to surgical stress.

PRINCIPLE FINDINGS

The key clinical features of perioperative catabolism are hyperglycemia and loss of body protein, both metabolic consequences of impaired insulin function. Muscle weakness and (even moderate) increases in perioperative blood glucose are associated with morbidity after major surgery. Although the optimal glucose concentration for improving clinical outcomes is unknown, most medical associations recommend treatment of random blood glucose > 10 mmol·L(-1). Neuraxial anesthesia blunts the neuroendocrine stress response and enhances the anabolic effects of nutrition. There is evidence to suggest that the avoidance of preoperative fasting prevents insulin resistance and accelerates recovery after major abdominal surgery.

CONCLUSIONS

Current anticatabolic therapeutic strategies include glycemic control and perioperative nutrition in combination with optimal pain control and the avoidance of preoperative starvation. All these elements are part of Enhanced Recovery After Surgery (ERAS) programs.

[Preoperative management for malnourished patients in abdominal surgery. Practical treatment regimen for reduction of perioperative morbidity]

The incidence of malnutrition in oncological and visceral surgical units can be high. The screening of malnourished patients is very important, especially in the preoperative setting. The available published literature provides crucial knowledge about the risks inherent to malnutrition and subsequent perioperative morbidity and mortality. The preoperative screening of malnourished patients followed by a subsequent renutrition is the key to decreasing rates of postoperative morbidity and mortality. The data and guidelines given by the European Society of Parenteral and Enteral Nutrition (ESPEN) in 2006 for the preoperative nutritional conditioning are clear and give no doubt regarding the necessity of preparation of malnourished patients for elective abdominal surgery. Despite this fact, the observance and application of these guidelines among German surgical units remain low. To fill this void a model of systematic screening and treatment of malnutrition in the preoperative setting for elective abdominal surgery was created and implemented at the university hospital of Oldenburg. A practical treatment regimen was designed to prepare malnourished patients within 2-3 weeks before elective surgery. Initial results regarding the feasibility of preoperative home renutrition therapy were moderate but encouraging. The success of such a conditioning process depends on cooperation between the surgical unit, the general practitioner (GP) and the homecare environment. In the German healthcare system the prescription of home nutrition (i.e. enteral feeding) can lead to the prescription limits of a GP being exceeded and has to be justified to the medical insurance company in each case. This article presents a simple yet applicable way of screening and preparing malnourished patients a few weeks prior to elective surgery. Therefore, simple tools which can be promptly used in daily clinical life, especially in the outpatient surgical consultations prior to elective visceral surgery are proposed.

Nutrition optimization prior to surgery

Optimization of metabolic state prior to major surgery leads to improved surgical outcomes. Nutrition screening protocols should be implemented in the preoperative evaluation, possibly as part of a bundle. Strategies to minimize hyperglycemia and insulin resistance by aggressive preoperative nutrition and carbohydrate loading may promote maintenance of a perioperative anabolic state, improving healing, reducing complications, and shortening the time to recovery of bowel function and hospital discharge. Short courses of preoperative immune-modulating formulas, using combinations of arginine, ω-3 fatty acids, and other nutrients, have been associated with improved surgical outcomes. These immune-modulating nutrients are key elements of metabolic pathways that promote attenuation of the metabolic response to stress and improve both wound healing and immune function. Patients with severe malnutrition and gastrointestinal dysfunction may benefit from preoperative parenteral nutrition. Continuation of feeding through the intraoperative period for severely stressed hypermetabolic patients undergoing nongastrointestinal surgery is another strategy to optimize metabolic state and reduce prolonged nutrition deficits. In this paper, we review the importance of preoperative nutrition and strategies for effective preoperative nutrition optimization.