It will probably come as no surprise that patients who are malnourished are prone to complications during wound healing. Mild malnutrition may cause a delay in wound healing, while severe malnutrition can lead to infection, sepsis and even death. For this reason, it is important to perform a nutritional assessment on patients presenting with a wound, especially patients with chronic wounds, as making nutritional changes can enhance wound healing.
Components of nutritional screening
Nutritional screening must include individual patient characteristics that might suggest that the patient may have difficulties during wound healing, diet history, characteristics of the patient’s wound and underlying health conditions of the patient (comorbidities).
Patient characteristics that suggest malnutrition include:
- pallor/pale skin
- dull or thinning hair
- redness or swelling of the mouth or tongue
- poor dentition/mouth sores
- conjunctival pallor
- dry skin
- orthostatic hypotension
Weight & Wound Healing
The patient’s weight, in particular BMI, can identify patients that are underweight or overweight, both of which can predispose to wound healing complications. The body mass index, or BMI, is calculated by obtaining the patient’s height and weight and dividing weight by height: kg/m². A BMI of 18.5 to 24.9 is considered “normal”. Keep in mind that patients with very small or very large frames may not fit within the norm. It is also important to realize that patients who are overweight or obese are at risk for poor wound healing, not just patients who are underweight.
Obtaining a diet history can help the practitioner identify areas for nutritional improvement; for example, patients who are not taking in adequate amounts of fluids, calories or protein to support wound healing, or diabetics patients who are consuming too many simple sugars and fats. Making dietary adjustments can make a huge difference in wound healing.
Components of Laboratory Testing
In addition to performing nutritional screening, certain laboratory tests can identify patients at risk for malnutrition. The seven most common blood tests used to determine nutritional status are:
- Serum Albumin- a plasma protein produced by the liver; decreased serum albumin levels are associated with pressure ulcers (increasing severity) and edema (Serum Albumin- normal levels; at least 3.5 mg/dL)
- Prealbumin- a major transport protein; as prealbumin levels drop, risk of mortality rises; unlike serum albumin, prealbumin is not affected by hydration status of the patient (normal values; 16–40 mg/dL)
- Blood glucose- poor glycemic control is associated with impaired wound healing and an increased risk of ulceration Blood glucose (normal levels; 70–110 mg/dL)
- Creatinine- a measurement of protein status and kidney function; creatinine levels are decreased in malnutrition (normal levels; 0.8–1.5 mg/dL)
- Blood urea nitrogen (BUN)- an indicator of kidney function, urea is a by-product of protein metabolism; elevated BUN levels are associated with poor wound healing (BUN; normal levels; 5–25 mg/dL)
- Serum transferrin- a sensitive indicator of protein status; will increase with iron deficiency and decrease with protein deficiency (levels less than 170 mg/dL indicate malnutrition)
- Total lymphocyte count (TLC)- an indirect measurement of immune functioning and nutritional status; decreased TLC is associated with delayed wound healing and increased mortality
Certain comorbidities have a strong influence on wound healing due to the fact that they impact upon the patient’s nutritional status. The following may adversely affect the patient’s ability to obtain enough calories, protein, fluids and other necessary nutritional components:
- prolonged NPO status
- gastrointestinal dysfunction (i.e. malabsorption)
- enteral feeding/TPN
Nutrition & Types of Wounds
Certain types of wounds that may require special attention to nutrition in order to prevent impaired wound healing include:
- repeat ulcerations
- pressure ulcers
- large surface area burns
- neuropathic ulcers
- chronic wounds
Nutritional status is directly linked to wound healing. Ensuring that the patient’s nutritional status is adequate can help to minimize the risk of complications in wound healing, such as infection and delayed wound healing.
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