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UNIT 4 Supporting Physiological Function
Impaired Mobility A healthy person moves and shifts position uncon- sciously when they sense pressure or discomfort. How- ever, for people who are unable to move independently or lack sensation in a body area, the weight of the body on the bed or chair causes an increase in pressure that can lead to skin tissue injury. Examples of conditions that increase the risk for immobility-related pressure injury include paralysis, extreme fatigue, high-risk pregnancy, sedation, casts, traction, and altered sensory perception. Knowledge Check 32-1 ■ Identify the major functions of the skin. ■ What is the function of the stratum corneum, the outermost layer of the skin? ■ What is the function of the subcutaneous layer? ■ What effect does aging have on the skin? ■ What effect does immobility have on the skin? Nutrition and Hydration Skin condition reflects a person’s overall nutritional sta- tus because nutritional intake affects the skin. Adequate intake of protein, cholesterol, calories, fluid, vitamin C, and minerals is essential to maintaining skin integrity. Protein Healthy skin depends on adequate protein levels to maintain the skin, repair minor defects, and pre- serve intravascular volume. As protein levels decline: ■ Skin injury is slow to heal, and minor defects cannot be repaired. ■ Fluid leaks from the vascular compartment of depen- dent areas, and edema (excess fluid in the tissues) develops. ■ Edema decreases skin elasticity and interferes with the diffusion of oxygen to the cells. Therefore, the skin becomes prone to breakdown. Cholesterol Low cholesterol levels predispose patients to skin breakdown and inhibit wound heal- ing. Patients on low-fat tube feedings may experience deficiencies in cholesterol, fatty acids, and linoleic acid. Together, these fats aid in providing fuel for wound healing and maintain a waterproof barrier in the stra- tum corneum. Calorie Intake If calorie intake is inadequate, the body uses proteins for energy (catabolism); they are then unavailable for building and maintenance func- tions (anabolism) (see Chapter 24 as needed). With prolonged malnutrition, the person experiences weight loss, loss of subcutaneous tissue, and muscle atrophy. As a result, padding between the skin and the bones decreases, predisposing the skin to a pressure injury. Ascorbic Acid, Zinc, and Copper Vitamin C (ascorbic acid), zinc, and copper are involved in the formation and maintenance of collagen. A deficiency of any of these elements can delay wound healing.
Hydration Poor skin turgor may occur because of dehydration, whereas edema may result from over- hydration. Both dry, dehydrated skin and edematous, overhydrated skin are prone to injury, especially when exposed to pressure, shearing, friction, and moisture. For further discussion on fluid requirements, see Chapter 35. Diminished Sensation or Cognition If you’ve ever touched a hot surface and quickly pulled back your hand, you know the importance of tactile sensation. Patients with peripheral vascular disease, spinal cord injury, diabetes, cerebrovascular accident, trauma, or fractures often have diminished
Pressure Injury and the Effect of Nutritional Support on Healing
Situation: While caring for an emaciated patient after surgery, the nurse notes two new wounds on the patient's bony prominences. Pressure injury has developed secondary to the patient's immobility, friction, shear, and postoperative drainage. PICOT Components: P Population/patient = Malnourished adults I Intervention/indicator = Nutritional supplements C Comparator/control = Diet without supplements O Outcome = Improved (or faster) healing time T Time = Searchable Question: Do (P) who receive/are exposed to (I) demonstrate (O) compared with (C) during (T)? Example of Evidence: Protein intake has been associated with improved wound healing.To prevent pressure wounds, many acute and long-term care facilities recommend that patients' diets have increased protein content.To examine the effect of nutritional intervention in pressure injury care, researchers reviewed seven research studies on the use of oral nutritional supplementation enriched with arginine (an amino acid), vitamin C, and zinc for pressure injury care. Results showed improved pressure injury healing and reduced risk of developing a pressure injury. Practice Change: The nurse caring for patients at risk for pressure wounds needs to address the patients' nutritional needs, including a diet high in protein. Sources: Munoz, N., Posthauer, M. E., Cereda, E., Schols, J., & Haesler, E. (2020).The role of nutrition for pressure injury prevention and healing:The 2019 international clinical practice guideline recommendations. Advances in Skin and Wound Care, 33 (3), 123–136. https://doi.org/10.1097/01.ASW.0000653144.90739.ad
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