Nutrition and its relationship to the prevention and treatment of wounds has increased significantly during the past 25 years. In 1987, Allman et al1 noted that malnutrition was a risk factor for pressure ulcer (PrU) healing. Nutrition interventions, however, were rarely part of the plan of care, and most of the recommendations involved support surfaces and wound care treatments.
The Agency for Health Care Policy and Research (now the Agency for Healthcare Research and Quality) 1994 guideline included a nutrition assessment and support guide for clinicians to manage the nutritional needs of patients with PrUs.2 The 1994 guide noted that serum albumin less than 3.5 mg/dL was a clinical indicator of a diagnosis for malnutrition. Current research including randomized, interventional, or prospective cohort studies indicates that albumin and prealbumin (transthyretin) are acute-phase proteins affected by the inflammatory process. These levels decline in the presence of infection, trauma, surgery, burns, or edema. Depressed levels of albumin and prealbumin are indicators of morbidity and mortality, not declining nutrient intake, and increased levels reflect improvement in the clinical status of the individual.3-5 Evaluation of biochemical data is only one aspect of the nutritional assessment process and should be considered with other factors, such as weight changes, current food/fluid intake, diagnosis, and medication. The registered dietitian (RD) now has an established role as a member of the interdisciplinary healthcare team. Registered dietitians are responsible for assessing the nutritional status of individuals and recommending intervention (based on science) for the prevention and treatment of wounds.
Because malnutrition is a reversible risk factor for PrU development, early detection is important. Clinicians should use validated nutrition screening and assessment tools to determine nutritional status. Validated screening and assessment tools are commonly used in Europe. The Malnutrition Universal Screening Tool6 and the Short Nutritional Assessment Questionnaire are used in hospitals. The Mini-Nutritional Assessment-Short Form has recently been validated for use in both the community and long-term-care facilities.7 The 2009 National Pressure Ulcer Advisory Panel (NPUAP)/European Pressure Ulcer Advisory Panel (EPUAP) guideline recommends early screening and assessment with referral of individuals at nutritional/PrU risk to a multidisciplinary team that includes an RD. The Braden Risk Assessment Scale: Predicting PrU Risk includes a nutrition subscale. Based on the distribution of points in the subscales, 17% of PrU risk is attributable to food/fluid intake.8 A prospective study using the Braden Scale validated the importance of adequate protein consumption as a prevention strategy.9
Protein is essential to promote positive nitrogen balance, and all stages of healing require adequate protein.10 Studies focusing on older adults suggest that the minimum protein allowance should be 1.0 versus 0.8 g/kg of body weight for healthy adults.11,12 Research supports a protein allowance of 1.2 to 1.5 g/kg of body weight for individuals with PrUs when compatible with goals of care.13 The importance of arginine, cysteine, and glutamine, which are conditionally essential amino acids during periods of stress, has emerged over the past decade. Many supplements formulated for wound healing contain conditionally essential amino acids alone or in combination with other nutrients. Research to confirm their impact on PrU healing continues. The type and variety of protein supplements on the market have exploded in the past few years. In addition to the traditional wheybased powered supplements, there are liquid protein products that provide 15 to 20 g/oz. Protein bars traditionally eaten by athletes are appropriate for individuals with wounds.
Over the past 25 years, the number and type of nutrition or medical food supplements have increased. There are foods ranging from bread, cereal, cookies, ice cream, pudding, potatoes, and so on that are fortified to enhance the nutrient intake of energy, protein, fiber, and/or fat, which may also contribute to the vitamin and mineral intake of the diet. The composition of liquid commercial supplements may have 1, 1.2, 1.5, or 2 kcal/oz of product. These products often supply key vitamins and minerals important for wound healing, such as vitamin C and zinc.
When adequate nutrition cannot be achieved orally, enteral/parenteral nutrition is appropriate if consistent with the individual's goals. The focus of research over the past 3 decades has been on modulating the body's response to illness and using individual nutrients as adjunct therapy. Arginine and n-3 fatty acids are being studied for their effect on the immune response and wound healing.14,15 Nondigestible oligosaccharides (prebiotic), which stimulate the growth of beneficial bacteria in the gastrointestinal tract, are being added to formulas.16 Frequently, individuals with wounds also have infections and are prescribed antibiotics, which damage the intestinal microbiota and slow the healing process.
Many organizations have published PrU prevention and treatment guidelines that have nutrition recommendations. Some of the guidelines, such as the 2009 NPUAP/EPUAP, are based on a rigorous, systemic review of research.13 Nutrition guidelines help practitioners make decisions that are appropriate for a specific condition. The RD and/or healthcare team is responsible for keeping up to date on emerging research that will affect their decisions. The American Dietetic Association's (ADA's) Evidence Analysis Library has published evidence-based guidelines on a number of nutrition topics.17 The ADA's 2011 wound care guidelines identified key topics for research, including the nutrient needs of obese individuals and dialysis patients with PrUs and the influence inflammation has on nutritional status. Nutrition is a young science, and research in the next 25 years may provide answers to these questions.
References