Chapter 42

Pressure Ulcers

Prevention and Management

Pressure ulcers (PUs) are a significant health problem in U.S. acute care facilities. Among all hospitalized patients, the highest prevalence of acquired pressure ulcers is in intensive care unit (ICU) patients, from 14% to 42%. An estimated 60,000 patients die each year from PU complications, denoting a poor overall prognosis.

PUs are painful, impair quality of life, and are expensive to treat. The Centers for Medicare and Medicaid Services (CMS) report that the cost of treating a single full-thickness PU in acute care is $43,180 per hospital stay. Increasingly, external regulatory agencies consider all PUs preventable, and CMS no longer reimburses hospitals for the added costs to treat hospital-acquired PUs.

Definition and Etiology

The National Pressure Ulcer Advisory Panel (NPUAP) and European Pressure Ulcer Advisory Panel (EPUAP) define pressure ulcers as “localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear.” Unrelieved pressure leads to decreased tissue perfusion and ischemia, culminating in tissue damage and PU formation. Reperfusion, after prolonged ischemia, may increase the damage due to free radicals. In the presence of friction and/or shearing forces, PUs develop faster than under non-shearing conditions.

Although pressure is always a component factor, multiple other risk factors for PUs exist. Many of these other risk factors affect tissue tolerance, that is, the ability of the skin and soft tissue to absorb and tolerate mechanical load. Tissue tolerance is influenced by both extrinsic factors (e.g., moisture, friction/shear) and intrinsic factors (e.g., perfusion/oxygenation, nutrition, severity of illness, body habitus, edema and chemical exposure to fecal incontinence). The number and severity of intrinsic factors for tissue tolerance in critically ill patients may help explain the disproportionate incidence of PUs in this vulnerable population.

Pressure ulcers are classified based on the depth and layer of tissue involvement, typically in accord with the NPUAP classification system (see Table 42.E1). Historically, the term stages created a mistaken notion that all PUs commonly begin superficially (i.e., Stage I) and progress sequentially to the deeper Stages II, III, or IV. To the contrary, research using diagnostic ultrasound reveals that PUs begin with deep tissue injury moving from the bone outward.

The most common PU sites are the sacrum, heels, greater trochanter, and ischial tuberosity. Medical devices such as cervical collars; nasogastric, nasoenteral, and endotracheal tubes; Foley catheters; and non-invasive ventilation masks can also create pressure.

TABLE 42.E1

National Pressure Ulcer Advisory Panel Pressure Ulcer Stages/Categories

Category/Stage	Definition
Category/Stage I: Non-blanchable erythema	Intact skin with non-blanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area. The area may be painful, firm, soft, warmer, or cooler as compared to adjacent tissue. Category I may be difficult to detect in individuals with dark skin tones. May indicate “at risk” persons.
Category/Stage II: Partial thickness	Partial thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed, without slough. May also present as an intact or open/ruptured serum-filled or sero-sanguinous filled blister. Presents as a shiny or dry shallow ulcer without slough or bruising.^∗ This category should not be used to describe skin tears, tape burns, incontinence, associated dermatitis, maceration, or excoriation.
Category/Stage III: Full thickness skin loss	Full thickness tissue loss. Subcutaneous fat may be visible but bone, tendon, or muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling. The depth of a Category/Stage III pressure ulcer varies by anatomic location. The bridge of the nose, ear, occiput, and malleolus do not have (adipose) subcutaneous tissue and Category/Stage III ulcers can be shallow. In contrast, areas of significant adiposity can develop extremely deep Category/Stage III pressure ulcers. Bone/tendon is not visible or directly palpable.
Category/Stage IV: Full thickness tissue loss	Full thickness tissue loss with exposed bone, tendon, or muscle. Slough or eschar may be present. Often includes undermining and tunneling. The depth of a Category/Stage IV pressure ulcer varies by anatomic location. The bridge of the nose, ear, occiput, and malleolus do not have (adipose) subcutaneous tissue and these ulcers can be shallow. Category/Stage IV ulcers can extend into muscle and/or supporting structures (e.g., fascia, tendon, or joint capsule) making osteomyelitis or osteitis likely to occur. Exposed bone/muscle is visible or directly palpable.
Unstageable/Unclassified: Full thickness skin or tissue loss — depth unknown	Full thickness tissue loss in which the base of the ulcer is covered by slough (yellow, tan, gray, green, or brown) and/or eschar (tan, brown, or black) in the wound bed. Until enough slough and/or eschar is removed to expose the base of the wound, the true depth cannot be determined; but it will be either a Category/Stage III or IV. Stable (dry, adherent, intact without erythema or fluctuance) eschar on the heels serves as “the body’s natural (biological) cover” and should not be removed.
Suspected deep tissue injury — depth unknown	Purple or maroon localized area of discolored intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer, or cooler as compared to adjacent tissue. Deep tissue injury may be difficult to detect in individuals with dark skin tones. Evolution may include a thin blister over a dark wound bed. The wound may further evolve and become covered by thin eschar. Evolution may be rapid exposing additional layers of tissue even with optimal treatment.

^∗Bruising indicates deep tissue injury.

Reproduced from National Pressure Ulcer Advisory Panel with permission.

Risk Assessment and Prevention

A large number of factors influence an individual’s risk to develop PUs. In critically ill patients, these risk factors are exaggerated. Formal risk assessment scales such as the Braden scale are widely accepted and recommended, but omit common ICU predisposing conditions such as intense vasoconstrictive drug therapy, hemodynamic instability, and mechanical ventilation (Table 42.1). Recommendations for preventing PUs start with identifying patients at risk and implementing prevention strategies (Table 42.2). Although there are clinical circumstances in which a pressure ulcer is unavoidable, PU incidence and prevalence can be reduced when evidence-based guidelines and bundles are rigorously used.

TABLE 42.1

Risk Factors for Pressure Ulcers

Risk Factors in Braden Scale	Risk Factors in the Critically Ill
Sensory perception Immobility Activity Incontinence Nutrition Friction and shear	Duration of surgery Fecal incontinence and/or diarrhea Low albumin Altered sensory perception Edema Skin moisture Impaired circulation Use of inotropic drugs Mechanical ventilation Diabetes mellitus Too unstable to turn Decreased mobility Multiple devices

TABLE 42.2

SKIN CARE© Bundle

Support surfaces
Keep repositioning
Incontinence care
Nutrition and hydration
Careful lifting
Assess risk and skin daily
Reduce HOB ≤ 30° (unless contraindicated)
Elevate heels
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