Assessing Malnutrition in Wound Healing
Nutritional deficiency is the term used when the reserves of nutrients stored in the body are insufficient to support healthy cellular function. A wound acts as a parasite on the body, requiring nutrients to be redirected from their normal functions to use in the various stages of the healing process. However, when the individual is malnourished, any trauma may prove disastrous as they lack the reserves to respond to the metabolic demands of the wound.
It is worth noting that malnutrition refers to an unbalanced diet with either a deficiency or excess of key nutrients.
The nutrients required for wound healing can be divided into two groups: macronutrients and micronutrients. Macronutrient refers to carbohydrates, proteins, and fats, whereas micronutrients refers to vitamins and minerals. Micronutrients generally support the functions of macronutrients and as such, are vitally important to the wound healing process. Fluids/water is an important nutrient and also plays a role in healing. See below for the breakdown of the roles played by macro- and micronutrients in wound healing:
• Proteins: Vital to the healing process. Supports platelet function, fibroblast proliferation, and wound remodeling. Helps with formation of lymphocytes, collagen, and new vasculature. To learn more about specific proteins, visit here.
• Carbohydrates: Provides the energy for recovery. Glucose is vital to wound healing as it supports cell growth, fibroblasts, and leukocytes. Also it plays a vital role in cell communication as a part of the immune response. Energy needs must be met to prevent the breakdown and utilization of protein for energy vs. healing.
• Fats: Helps meet the increased caloric demand that results from post-trauma hypermetabolism. Influences the localized metabolism of the wound. Helps modulate inflammation and the immune response.
• B Vitamins: Moderates local wound metabolism and tissue synthesis. Participates in collagen synthesis.
• Vitamin C: Helps stabilize collagen, which increases the tensile strength of the wound tissues. Supports free radical metabolism.
• Vitamin D: Regulates growth and differentiation of cells, including lymphocytes, melanocytes, and fibroblasts.
• Vitamin K: Required for blood clotting.
• Zinc: Supports protein synthesis and immune functions. Vital for cell growth and proliferation, liberates vitamin A from the liver, interacts with platelets in flood clotting; Mega doses of zinc may inhibit healing and cause copper deficiency.
• Iron: Delivers oxygen to tissues. Generation of energy from cells, transferrin, a blood protein, transfers iron to the tissues of the bed.
• Copper: Helps facilitate angiogenesis. Assists with cross linking of collagen fibers to rebuild tissue.
Fluid serves as the solvent for minerals, vitamins, amino acids, and glucose, maintains fluid and electrolyte balance.
Screening tools that are quick, easy to use and have been validated should be used to identify individuals who are at risk for malnutrition.
Once it has been determined that the individual is at risk, they should be referred to the registered dietitian who will complete an assessment and determine the appropriate calories, protein and other nutrients needed for healing.
A variety of tools are available for nutritional assessment, such as the Malnutrition Screening Tool (MST), the Short Nutritional Assessment Questionnaire (SNAQ) and the Mini-Nutritional Assessment-Short Form (MNA-SF®).
The Malnutrition Screening Tool (MST) and the Short Nutritional Assessment Questionnaire (SNAQ) were developed to help nurses quickly screen nutritional status in acute care settings. The MST tool has three parameters: body mass index (BMI) with alternative measures noted if BMI is not appropriate, weight loss, and the acute disease effect score. The total of the three scores identifies low, medium or high risk nutritional status and includes appropriate interventions linked to each level of risk
The MNA-SF ® is validated in both the community and healthcare setting specifically for adults over 65. The questions on the MNA-SF® address appetite, weight loss in the past three months, mobility, psychological stress or acute disease, neuropsychological problems, and BMI. Additional tools are the Subjective Global Assessment (SGA) and the Nutrition Risk screening (NRS-2002)
Weight loss, low BMI, and appetite, which are predictors for the risk of malnutrition, are common characteristics of these validated tools.
In May 2012, the Academy of Nutrition and Dietetics and the American Society for Parenteral and Enteral Nutrition (ASPEN) published a consensus statement on the characteristics recommended for the identification and documentation of adult malnutrition which assists clinicians in identifying this increasing problem, which contributes to increased morbidity and mortality.
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-White J. Consensus Statement: AND and ASPEN: characteristics recommended for the identification and documentation of adult malnutrition (undernutrition.) J Acad Nutr Diet. 2012 112(5): 730-738.
-Nestle Nutrition Institiute. MNA®Minu Nutritional Assessment. http://www.mna-elderly.com/mna_forms.html. Accessed April 3, 2013.
-Fight Malnutrition. Screening Tools. http://www.fightmalnutrition.eu/malnutrition/screening-tools/. Accessed April 3, 2013. —Bapen. Introducing ‘MUST’. 2013. http://www.bapen.org.uk/must_tool.html. Accessed April 3, 2013.