VOL: 98, ISSUE: 44, PAGE NO: 62
Andrea Cartwright, RN, BSc, is nutritional nurse specialist, Basildon and Thurrock General Hospitals NHS TrustNutrition requires complex multidisciplinary organisational structures in hospitals but is often neglected. Patients' nutritional status has been shown to deteriorate while in hospital (McWhirter and Pennington, 1994), especially in elderly people and in those whose nutritional status is already compromised.
Nutrition requires complex multidisciplinary organisational structures in hospitals but is often neglected. Patients' nutritional status has been shown to deteriorate while in hospital (McWhirter and Pennington, 1994), especially in elderly people and in those whose nutritional status is already compromised.
Relevance of nutrition in wound healing
Nutrients are chemical substances supplied by food and are required for growth, maintenance and repair and therefore essential in wound healing.
Macronutrients are substances that form the biggest part of a person's daily nutrient and energy requirements and include protein, carbohydrates and fats (Silk, 1997). Micronutrients are those that are only required in small amounts but are essential. They can be described as trace elements or vitamins (Gidden and Shenkin, 1997)
Causes of poor wound healing
The main reasons why wounds fail to heal are infection, poor nutrition and impaired organ function (Johnson, 1993). Not all wounds heal in the same way, and it is therefore inadvisable to compare a clean surgical wound to that of an extensive burn (Albina, 1994). However, factors that contribute to poor wound healing should not be looked at in isolation and should be part of a holistic approach to wound management.
There is evidence that poor pre-operative nutritional status adversely effects wound healing (Haydock and Hill, 1986), delays healing and increases the risk of wound dehiscence (Ruberg, 1984), and that dietary intervention can improve or accelerate wound healing.
Role of macro and micronutrients in wound healing
In order for a wound to heal there must be fuel and an adequate blood supply to carry energy and oxygen to the regenerating cells. Macro- and micronutrient have a number of functions. They provide a fuel source, are components of the regenerating cells and components and co-factors to many enzymes. They enhance the immune response and modulate the inflammatory response (Gidden and Shenkin, 1997; Silk, 1997). The effects of individual macro- and micronutrients in wound healing are shown in Tables 1 and 2.
When a severe injury has occurred, nutritional requirements may be greatly complicated by metabolic disturbances as a result of the neuroendocrine responses and profound tissue and organ damage. Inflammatory changes take place within minutes of surgical intervention or injury. The resulting pro-inflammatory cascade suppresses the immune system (Cerra, 1991).
Much of the current research in nutrition focusses on the modulation of the inflammatory process, to promote repair and healing, as well as reducing organ failure and restoring the immune system (Colagiovanni, 2000). This is called immunonutrition and is the use of specific nutrients that modify the immune response. The specific nutrients include glutamine, arganine, omega 3 polyunsaturated acids and nucleotides.
Although the potential for manipulating the immune response - thus altering the outcome of surgical intervention - exists, there is little evidence to support its routine use in clinical practice (Lin et al, 1998).
Practical information on nutritional assessment
Nutritional requirements for individuals vary according to age, gender, activity and severity of illness. As nurses have the responsibility to ensure that patients receive adequate nutrition, nutritional screening and admission assessment of nutritional status is well within their domain. It is important to distinguish between nutritional screening and nutritional assessment.
Nutritional screening uses tools or aids to memory and includes a quantitative assessment to identify patients at nutritional risk (McLaren et al, 1998). Nutritional risk can be defined as 'the degree of risk of individuals becoming clinically malnourished' (Lyne, 1999) and should take into account predisposing factors (Table 3).
Nutritional screening should ideally be carried out during the admission process and re-assessed weekly (or more frequently if the clinical situation changes). Identifying patients with malnutrition or those who could develop malnutrition enables resources to be directed towards patients in most need and highlights those who would benefit from further nutritional assessment by the dietitian or nutrition support team.
When adopting or developing nutritional screening tools, ensuring that they meet criteria for validity, reliability and sensitivity will enable the instrument to accurately place patients in the correct risk category (McLaren and Green, 1998).
Nutritional assessment is a much more complex task and is usually carried out by a dietitian or suitably trained physician. It combines dietary history, physical assessment and anthropometry with biochemical analysis (Whitney et al, 1998), to provide a much more detailed account of nutritional status. Dietitians are specifically trained in this technique and in the provision of nutritional support, but in the current climate it would be impossible for dietitians to assess all admissions as a matter of routine (Reilly, 1996).
Nurses and doctors must take greater responsibility in nutritional care in order to direct resources to those patients who need further assessment. Yet a survey for the British Association for Parenteral and Enteral Nutrition (BAPEN) demonstrated a lack of awareness, among health care professionals of the importance of nutritional status (Lennard-Jones et al, 1995).
The use of screening tools by nurses during the admission process has been found to improve the nutritional content of the nursing assessment (Brown, 1997). However, nurses are not always aware that they are collecting information on patients' nutritional status and therefore do not act on the information that they receive (Perry, 1997). It is clear that more education is needed in the area of patient nutrition and that the nutritional content of nursing courses needs to be re-evaluated.
Improving nutritional intake
Essence of Care (Department of Health, 2001) has handed nurses a tool kit to improve the quality of clinical care in eight fundamental areas, one of which is food and nutrition. This is patient-focused, clinical practice benchmarking aimed primarily at nurses, but should involve other health professionals as well. There are 10 factors within the food and nutrition element, designed to enable patients to meet their individual needs. The benchmarking is about sharing and comparing best practice and developing an action plan to remedy poor practice.
Assessing, recording, planning, monitoring and evaluating the nutritional needs of patients is a nursing responsibility and a fundamental aspect in the holistic care of patients with healing wounds. Nurses must become more involved in their patients' nutrition, gain knowledge in basic nutritional support and seek the help of other professionals to enable them do so.