Latest Research on Clinical Nutrition : Mar 2022

Preoperative Issues in Clinical Nutrition

Allowing a patient’s nutritional state to deteriorate through the perioperative period adversely affects measureable outcome related to nosocomial infection, multiple organ dysfunction, wound healing, and functional recovery. Careful preoperative nutritional assessment should include a determination of the level of stress, an evaluation of the status of the GI tract, and the development of specific plans for securing enteral access. Patients already demonstrating compromise of nutritional status (defined by > 10% weight loss and serum albumin level < 2.5 g/dL) should be considered for a minimum of 7 to 10 days of nutritional repletion prior to surgery. Widespread use of total parenteral nutrition in unselected patients is unwarranted, may actually worsen outcome, and should be reserved for preoperative nutritional support only in severely malnourished patients in whom the GI tract is unavailable. Compared with the parenteral route, use of perioperative enteral feeding has been shown to provide more consistent and beneficial results, and can be expected to promote specific advantages in long-term morbidity and mortality.[1]


Rationale and impact of vitamin C in clinical nutrition

Purpose of review
The impact of vitamin C on oxidative stress-related diseases is moderate because of its limited oral bioavailability and rapid clearance. Parenteral administration can increase the benefit of vitamin C supplementation as is evident in critically ill patients. The aim here is to assess recent evidence of the clinical benefit and underlying effects of parenteral vitamin C in conditions of oxidative stress.

Recent findings
In critically ill patients and after severe burns, the rapid restoration of depleted ascorbate levels with high-dose parenteral vitamin C may reduce circulatory shock, fluid requirements and oedema.

Summary
Oxidative stress is associated with reduced ascorbate levels. Ascorbate is particularly effective in protecting the vascular endothelium, which is especially vulnerable to oxidative stress. The restoration of ascorbate levels may have therapeutic effects in diseases involving oxidative stress. The rapid replenishment of ascorbate is of special clinical significance in critically ill patients who experience drastic reductions in ascorbate levels, which may be a causal factor in the development of circulatory shock. Supraphysiological levels of ascorbate, which can only be achieved by the parenteral and not by the oral administration of vitamin C, may facilitate the restoration of vascular function in the critically ill patient.[2]


A national survey of attitudes and practices of primary-care physicians relating to nutrition: strategies for enhancing the use of clinical nutrition in medical practice

A nationwide mail survey was used to determine the degree to which primary-care physicians indicated that they practice the “core competencies” in clinical nutrition identified by Young et al (Am J Clin Nutr 1983;38:800–10). We also surveyed the nutrition-related attitudes of these physicians. Although the 3416 physicians who responded to the survey tended to report favorable attitudes toward using nutrition in their practice, these favorable attitudes were not consistent with their own reports of clinical performance. Neither the positive- or negative-attitude score correlated highly with the reported behavior-practice score. The clinical practices reported by those surveyed are well below the minimum level defined by the Young et al essential core competencies in clinical nutrition. The attitudes, practices, and demographic characteristics associated with the clinical performance variables suggest educational strategies for improving the competence of primary-care physicians and medical students in clinical nutrition.[3]


Nutrition support in clinical practice: review of published data and recommendations for future research directions. Summary of a conference sponsored by the National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition

In the last 30 years, marked advances in enteral feeding techniques, venous access, and enteral and parenteral nutrient formulations have made it possible to provide nutrition support to almost all patients. Despite the abundant medical literature and widespread use of nutritional therapy, many areas of nutrition support remain controversial. Therefore, the leadership at the National Institutes of Health, The American Society for Parenteral and Enteral Nutrition, and The American Society for Clinical Nutrition convened an advisory committee to perform a critical review of the current medical literature evaluating the clinical use of nutrition support; the goal was to assess our current body of knowledge and to identify the issues that deserve further investigation. The panel was divided into five groups to evaluate the following areas: nutrition assessment, nutrition support in patients with gastrointestinal diseases, nutrition support in wasting diseases, nutrition support in critically ill patients, and perioperative nutrition support. The findings from each group are summarized in this report. This document is not meant to establish practice guidelines for nutrition support. The use of nutritional therapy requires a careful integration of data from pertinent clinical trials, clinical expertise in the illness or injury being treated, clinical expertise in nutritional therapy, and input from the patient and his/her family.[4]


ESPEN guidelines on definitions and terminology of clinical nutrition

Background
A lack of agreement on definitions and terminology used for nutrition-related concepts and procedures limits the development of clinical nutrition practice and research.

Objective
This initiative aimed to reach a consensus for terminology for core nutritional concepts and procedures.

Methods
The European Society of Clinical Nutrition and Metabolism (ESPEN) appointed a consensus group of clinical scientists to perform a modified Delphi process that encompassed e-mail communication, face-to-face meetings, in-group ballots and an electronic ESPEN membership Delphi round.

Results
Five key areas related to clinical nutrition were identified: concepts; procedures; organisation; delivery; and products. One core concept of clinical nutrition is malnutrition/undernutrition, which includes disease-related malnutrition (DRM) with (eq. cachexia) and without inflammation, and malnutrition/undernutrition without disease, e.g. hunger-related malnutrition. Over-nutrition (overweight and obesity) is another core concept. Sarcopenia and frailty were agreed to be separate conditions often associated with malnutrition. Examples of nutritional procedures identified include screening for subjects at nutritional risk followed by a complete nutritional assessment. Hospital and care facility catering are the basic organizational forms for providing nutrition. Oral nutritional supplementation is the preferred way of nutrition therapy but if inadequate then other forms of medical nutrition therapy, i.e. enteral tube feeding and parenteral (intravenous) nutrition, becomes the major way of nutrient delivery. Conclusion
An agreement of basic nutritional terminology to be used in clinical practice, research, and the ESPEN guideline developments has been established. This terminology consensus may help to support future global consensus efforts and updates of classification systems such as the International Classification of Disease (ICD). The continuous growth of knowledge in all areas addressed in this statement will provide the foundation for future revisions.[5]


Reference

[1] McClave, S.A., Snider, H.L. and Spain, D.A., 1999. Preoperative issues in clinical nutrition. Chest, 115(5), pp.64S-70S.

[2] McGregor, G.P. and Biesalski, H.K., 2006. Rationale and impact of vitamin C in clinical nutrition. Current Opinion in Clinical Nutrition & Metabolic Care, 9(6), pp.697-703.

[3] Levine, B.S., Wigren, M.M., Chapman, D.S., Kerner, J.F., Bergman, R.L. and Rivlin, R.S., 1993. A national survey of attitudes and practices of primary-care physicians relating to nutrition: strategies for enhancing the use of clinical nutrition in medical practice. The American journal of clinical nutrition, 57(2), pp.115-119.

[4] Klein, S., Kinney, J., Jeejeebhoy, K., Alpers, D., Hellerstein, M., Murray, M. and Twomey, P., 1997. Nutrition support in clinical practice: review of published data and recommendations for future research directions. Summary of a conference sponsored by the National Institutes of Health, American Society for Parenteral and Enteral Nutrition, and American Society for Clinical Nutrition. The American journal of clinical nutrition, 66(3), pp.683-706.

[5] Cederholm, T., Barazzoni, R.O.C.C.O., Austin, P., Ballmer, P., Biolo, G.I.A.N.N.I., Bischoff, S.C., Compher, C., Correia, I., Higashiguchi, T., Holst, M. and Jensen, G.L., 2017. ESPEN guidelines on definitions and terminology of clinical nutrition. Clinical nutrition, 36(1), pp.49-64.

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