Definition

A wound is defined as an injury to the skin, which may involve all layers of the skin, muscles, and supporting structures, often resulting in tissue loss. From a physiological perspective, wound healing is a highly complex process that occurs in several phases: inflammation, proliferation, and maturation ^1-3. Wounds are classified as acute or chronic, with chronic wounds defined as those that take longer than 12 weeks to heal ³. There are various types of wounds with different etiologies. Common types include surgical wounds, pressure ulcers, venous or arterial ulcers, and diabetic foot syndrome. This overview focuses on these types. Venous and arterial ulcers, as well as diabetic foot syndrome, often have chronic courses, while surgical wounds ideally heal within a few weeks.

Impact on Metabolism and Nutritional Status

Wound healing is associated with increased requirements for energy, protein, and micronutrients. These needs depend on the wound size and the underlying metabolic condition. Delayed wound healing is typically observed only when the wound is infected or in cases of severe malnutrition, particularly when there is a loss of at least 20% of lean body mass. In such cases, the body prioritizes protein distribution to the wound tissue, utilizing muscle as a protein reserve if dietary intake is insufficient ⁴. This can lead to protein-energy malnutrition (PEM), which may prolong recovery time. Therefore, wound patients should be screened for PEM risk, and nutritional therapy should be initiated promptly if a risk is identified ⁵.

Factors Limiting Appetite and Intake

• Underlying disease and comorbidities
• Wound-related pain
• Pain caused by wound care procedures and/or dressing changes
• Periods of fasting required for procedures, such as vacuum dressing changes in the operating room

Nutritional requirements for patients with wounds. Adjustments are necessary based on malnutrition status, physical activity, and patient age. Adjusted Body Weight (ADJ) is used for patients with a BMI ≥28; otherwise, the pre-hospitalization body weight is used.
BW = Body Weight; d = Day
 

Note: Renal Insufficiency: Lower protein levels are recommended (see Renal Chapter for details). Since wound healing is often prioritized in medical care, the protein levels mentioned above may be targeted under close monitoring of renal function, in agreement with the medical team.

Vitamins, Minerals, and Trace Elements

The increased demand for micronutrients due to wound healing is not fully understood. However, all vitamins and most minerals play a role in the wound healing process. Therefore, meeting the reference intake values for nutrients is advisable^1,5. Specific supplementation should only be conducted in cases of confirmed deficiencies or when the benefit-risk ratio is favorable^5,9.

Goals of Nutritional Therapy

• Promote wound healing
• Prevent protein-energy malnutrition (PEM)
• Improve and maintain nutritional status
• Enhance strength and mobility
• Preserve or optimize quality of life

Oral Nutrition

Energy and Protein Intake:

For patients at risk of PEM or with manifest PEM, a tailored, high-energy, and high-protein diet is indicated. Energy-dense foods, fortification, or oral nutritional supplements (ONS) may be utilized⁵.

Protein Quality & Immunonutrition:

Perioperative or postoperative immunonutrition with arginine (in combination with omega-3 fatty acids and nucleotides) may reduce the incidence of wound infections¹⁰.

For pressure ulcer patients, the best-studied immunonutritive combination includes arginine, vitamin C, zinc, and other antioxidants^11,12.

Alternatively, isolated supplementation of 4.5 g of arginine per day can be considered for pressure ulcer patients^12,13.

Supplementation with 15 g of arginine, 15 g of glutamine, and 3 g of beta-hydroxy-beta-methylbutyrate (HMB) may benefit patients with diabetic foot ulcers^14-16 or other chronic wounds¹⁷.

Fluid Intake:

Adequate hydration should be ensured as optimal hydration is crucial for perfusion, oxygen, and nutrient delivery to the wound site⁵. Fluid losses should be replaced in cases of suspected dehydration.

Micronutrients:

In cases where micronutrient deficiency is suspected due to inadequate energy intake or an unbalanced diet, a multivitamin supplement is recommended^1,5. Since micronutrients are essential co-factors in wound healing and can be limiting factors, deficiencies should be identified through individualized nutritional assessments.

• Vitamin C: For surgical patients and those with foot ulcers, supplementation of up to 1000 mg of vitamin C (either as two 500 mg doses or one 1000 mg extended-release form) can be recommended with minimal risk and weak evidence, even without measuring vitamin C levels^9,18. For patients with chronic kidney disease, caution is advised due to oxalate accumulation from vitamin C metabolism. In these cases, if deficiency is suspected, a lower dose of at least 90 mg/day for men and 75 mg/day for women is recommended¹⁹.
• Zinc: A supplementation of up to 40 mg/day for at least two weeks can be recommended for patients with pressure ulcers and venous ulcers, provided that an initial low plasma zinc level has been determined⁹.
• Selenium: While evidence from human studies on selenium supplementation to promote wound healing is lacking, supplementation can be considered in cases of proven deficiency.

Managing Diabetic Metabolic Conditions:

For patients with diabetes, glycemic control should be optimized without unnecessary dietary restrictions, as hyperglycemia is associated with delayed wound healing⁵.

Enteral Nutrition

Enteral nutrition is used when patients cannot consume adequate oral nutrition⁵. Various factors may contribute to this need. In an inpatient setting, large wounds may require dressing changes under sterile conditions in the operating room, resulting in frequent fasting periods. In such cases, supplemental enteral nutrition can be highly beneficial in compensating for the resulting energy and protein deficits.

Parenteral Nutrition

Parenteral nutrition is only considered when enteral nutrition is contraindicated or cannot provide adequate nutritional support for medical reasons.

Monitoring

In addition to monitoring nutritional and fluid status, the following parameters should be observed:

• Changes in wound size, depth, exudate volume, and signs of infection
• In cases of diabetes: HbA1c and serum glucose levels
• Pain levels (using a visual analog scale)
• Potential monitoring of plasma zinc levels (in combination with albumin and CRP)²⁰
• Potential monitoring of plasma selenium (in combination with CRP)²⁰
• Other specific micronutrients based on individual assessment

Special Considerations

Pressure ulcers are classified into four stages describing the extent of tissue damage:

• Stage 1: Skin is intact but red
• Stage 2: Visible superficial damage to the epidermis and dermis
• Stage 3: Damage extends through all layers of the skin, partially affecting underlying muscle
• Stage 4: Extensive tissue destruction, necrosis, or damage to muscles, bones, or supporting structures²¹

Medications/Supplements

Supplements: Refer to the section on nutritional therapy measures for specific recommendations.

Medications: Medications are used to manage pain, control diabetic metabolic conditions if present, and address the primary disease and any comorbidities.