NPUAP describes two additional categories of pressure ulcers: unstageable and deep tissue injury.3 An unstageable ulcer has full thickness skin or tissue loss of unknown depth because the wound base is completely obscured by slough or eschar. The ulcer can only be accurately categorized as Stage III or IV after sufficient slough or eschar is removed to identify wound depth. Lastly, suspected deep tissue injury describes a localized area of discolored intact skin (purple or maroon) or blood-filled blister due to damage of underlying tissue from pressure or shear.
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Table 1. National Pressure Ulcer Advisory Panel pressure ulcer staging classification3
Diagnosing infected pressure ulcers. Pressure ulcer infection delays wound healing and increases risks for sepsis, cellulitis, osteomyelitis, and death.5,6 Clinical evidence of soft tissue involvement, such as erythema, warmth, tenderness, foul odor, or purulent discharge, and systemic inflammatory response (fever, tachycardia, or leukocytosis) are suggestive of a wound infection.3,5 However, these clinical signs may be absent and thus make the distinction between chronic wound and infected pressure ulcer difficult.7 Delayed healing with friable granulation tissue and increased pain in a treated wound may be the only signs of a pressure ulcer infection.3,5,7
Routine laboratory tests (i.e. white blood cell count, C-reactive protein, and erythrocyte sedimentation rate) are neither sensitive nor specific in diagnosing wound infection. Moreover, because pressure ulcers are typically colonized with ≥105 organisms/mL of normal skin flora and bacteria from adjacent gastrointestinal or urogenital environments, swab cultures identify colonizing organisms and are not recommended as a diagnostic test for pressure ulcer microbiologic evaluation.5,6 If microbiological data are needed to guide antibiotic use, cultures of blood, bone, or deep tissue biopsied from a surgically debrided wound should be used.5 Importantly, a higher index of suspicion should be maintained for infection of Stage III or IV pressure ulcers because they are more commonly infected than Stage I or II ulcers.3
Prevention. The prevention of wound progression is essential in treating acute, chronic, or infected pressure ulcers. Although management guidelines are limited by few high-quality, randomized controlled trials, NPUAP recommends a number of prevention strategies targeting risk factors that contribute to pressure ulcer development.2,3,8
For all bed-bound and chair-bound persons with impaired ability to self-reposition, risk assessment for pressure ulcer should be done on admission and repeated every 24 hours. The presence of such risk factors as immobility, shear, friction, moisture, incontinence, and malnutrition should be used to guide preventive treatments. Pressure relief on an ulcer can be achieved by repositioning the immobile patient at one- to two-hour intervals. Pressure-redistributing support surfaces (static, overlays, or dynamic) reduce tissue pressure and decrease overall incidence of pressure ulcers. Due to a lack of relative efficacy data, the selection of a support surface should be determined by the patient’s individual needs in order to reduce pressure and shear.3 For instance, dynamic support is an appropriate surface for an immobile patient with multiple or nonhealing ulcers. Shearing force and friction can be reduced by limiting head-of-bed elevation to <30° and using such transfer aids as bed linens while repositioning patients. The use of pillows, foam wedges, or other devices should be used to eliminate direct contact of bony prominences or reduce pressure on heels.8
Skin care should be optimized to limit excessive dryness or moisture. This includes using moisturizers for dry skin, particularly for the sacrum, and implementing bowel and bladder programs and absorbent underpads in patients with bowel or bladder incontinence.2 Given that patients with pressure ulcers are in a catabolic state, those who are nutritionally compromised may benefit from nutritional supplementation.3 Lastly, appropriate use of local and systemic pain regimen for painful pressure ulcers can improve patient cooperation in repositioning, dressing change, and quality of life.