Prevention and Treatment of Pressure Ulcers

R. Gary Sibbald, MD^1,2,3; Laurie Goodman, RN, BA, MHScN⁴; Linda Norton, BScOT, OT Reg(ONT), MScCH⁵; Diane L. Krasner, PhD, RN, CWCN, CWS, MAPWCA, FAAN⁶;
Elizabeth A. Ayello, PhD, RN, ACNS-BC, CWON, MAPWCA, FAAN^7,8

¹Department of Medicine, University of Toronto, Toronto, ON, Canada
²Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
³Dermatology Day Care and Wound Healing Clinic, Sunnybrook and Women’s College Health Sciences, Toronto, ON, Canada
⁴Toronto Regional Wound Healing Clinics, Toronto, ON, Canada
⁵Shoppers Home Health Care, Toronto, ON, Canada
⁶Wound & Skin Care Consultant, York, PA, USA
⁷School of Nursing, Excelsior College, Albany, NY, USA
⁸The John A. Hartford Institute for Geriatric Nursing, New York University College of Nursing, New York, NY, USA

ABSTRACT

Pressure ulcer prevention and treatment remains a challenge for interprofessional teams in all health care sectors. Evidence based pressure ulcer guidelines can be simplified with a bedside enabler utilizing the wound bed preparation paradigm. Key steps involve treatment of the cause, addressing patient-centered concerns, and administering local wound care (debridement, infection/ inflammation control, and moisture balance before considering advanced therapies with the edge effect). Optimal outcomes are achievable with a multi-disciplinary approach that supports patients and their circle of care, which is central to every evaluation and course of treatment decisions.

Key Words:
algorithm, pressure ulcers, prevention, wound bed preparation, wound healing

Introduction

This best practice for the prevention and treatment of pressure ulcers (PrU) has been developed with the expertise of the authors and utilizing:

• The 2009 evidence-based guidelines developed in collaboration between the National Pressure Ulcer Advisory Panel and the European Pressure Ulcer Advisory Panel (NPUAP-EPUAP)^1,2
• The Registered Nurses Association of Ontario’s guideline for the prevention and treatment of pressure ulcers^3,4
• Canadian Association of Wound Care’s best practices for pressure ulcers⁵
• Wound Bed Preparation Update 2011⁶

The best approach to pressure ulcer management includes the patient and their circle of care along with an interprofessional team of health professionals including physicians, nurses, rehabilitation specialists, dietitians, and other allied health specialists.

Prevention

The holistic assessment to identify persons at risk of a pressure ulcer includes:

• Review of comorbidities and historical events (e.g., previous history of a pressure ulcer)
• Assessment of the patient’s skin, particularly over bony prominences
• Medication profile
• Use of a validated risk assessment tool

The routine assessment interval is based on patient acuity (e.g., daily in acute care units to weekly assessments in chronic care for the first 4 weeks and then monthly to quarterly). High risk individuals include those with advanced age, spinal cord injuries or other causes of immobility, and low body mass index (i.e., BMI below 20).

For adult patients there are three validated risk assessment scales: Braden, Waterlow, and Norton:

• Braden scale with 6 subscales (sensory/perception, moisture, activity, mobility, nutrition, and friction/shear) is most commonly used in North America⁷
• Waterlow scale with 9 subscales: (BMI, continence, skin type, mobility, appetite, tissue malnutrition, neurological deficit, major surgery/trauma, and medications)⁸
• Norton scale with 5 subscales (physical condition, mental condition, activity, mobility, and incontinence)⁹

The Braden scale scores between 6 and 23. A score of 18 or lower indicates an increased risk of developing a pressure ulcer. It is important to institute prevention strategies for each low scoring or high risk subscale item and use clinical judgment in addition to any risk assessment tool scores.

Despite optimal care, not all pressure ulcers are preventable as outlined in a recent consensus document (Skin Changes At Life’s End=SCALE).¹⁰

Pressure Ulcers

The international NPUAP-EPUAP defines a pressure ulcer 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.”¹

Findings from international PrU prevalence audits (447,930 patients) reported incidence rates of 9.2-27.3%.¹¹ Pressure ulcers are a significant financial burden on healthcare systems. Nonhealing/ chronic wounds are associated with increased length of hospital stay and mortality, and patients are at greater risk for developing complications such as cellulitis, osteomyelitis, and sepsis.

Determine Healability⁶

Categorization of wound healability (i.e., healable, maintenance, or non-healable) is of particular importance. This designation defines for the clinician, patient, and family an expected course of action, plan of care, and predictable healing rate. As a prerequisite to setting realistic treatment objectives, wounds are differentiated as:

• Healable wound: the cause is corrected, there is enough blood supply to heal; moist interactive healing
• Maintenance wound: the wound could heal, but the cause is not corrected due to patient unwillingness to adhere to treatment or a lack of required system resources
• Non-healable wound: the patient is ill or may have negative protein balance or inadequate blood supply that is not bypassable or dilatable

Other cofactors/comorbidities such as systemic disease, nutrition, and medications may also delay or inhibit healing in all of the above groups. For maintenance and non-healable wounds, moisture balance is contra-indicated and antiseptics including povidone iodine, chlorhexidine or its derivative polyhexamethylene biguanide (PHMB) may be prudent choices in a gauze or packing format. Conservative debridement of slough can, however, be undertaken to prevent spread of infection to local or deeper surrounding tissues through moisture and bacterial reduction.

Treat the Cause: Pressure and Shear

The foundation of the prevention and management of pressure ulcers is to reduce the forces of pressure and shear that damage the skin in the deep tissue compartments, particularly subcutaneous fat and muscle. Pressure is defined as the “force per unit area exerted perpendicular to the plane of interest.”¹² Shear is the “force per unit area exerted in parallel to the plane of interest.” Appropriate pressure reduction is outlined in Table 1. To minimize shear (the axial skeleton moves in opposite direction to the skin surface), do not raise the head of the bed more than 30 degrees and avoid slipping or sliding with transfers or in various types of seating.

Nutrition¹⁵

The nutritional assessment should include body mass index (BMI), hemoglobin (Hgb), and serum albumin level. The BMI is normal between 20-25, with levels <30 obese, and <40 morbidly obese. A BMI of >20 poses an increased risk of pressure ulcer development. Investigations of nutritional status should include Hgb (110-120 normal, ≥100 for normal healing, 80-100 for delayed healing, and 60-80 will severely impair the wound healing process). The albumin measures the protein status over the past few months in the peripheral circulation. Normal albumin levels are above 30-33, with delayed healing at levels between 20-30, and at <20 it will be very difficult to heal a wound. Nutritional support should include adequate protein intake of 10-20 g/kg/day. Zinc deficiency is uncommon in adults and its supplementation can interfere with absorption of other nutrients.

Immobility, Level of Activity and Positioning

Persons with spinal cord injuries (SCI)¹⁶ and neuromuscular degenerative disease are at an increased risk of developing a pressure ulcer. Interprofessional team members can offer patient-specific strategies for safe and optimal activity levels for individuals with a pressure ulcer. These consultations should actively engage input from both the patient and their circle of care with respect to an exercise program (e.g., in bed, movements or positioning during seating, assisted ambulation, and training equipment). Even with therapeutic surfaces, persons with PrU’s require a regular turning program based on their risk level and ability to perform voluntary changes in position.

Moisture and Friction¹⁷

Excess moisture may be due to sweat but is more often associated with urinary or fecal incontinence. Fecal incontinence is most harmful in the sacral area and a bowel routine or external collection device should be considered, as well as prompt changing of wet underwear or diapers. Urinary incontinence may be controlled with intermittent catheterization, a condom catheter, or an indwelling catheter; however, their use is associated with other complications including infections.

Friction is “the resistance to motion in a parallel direction relative to the common boundary of two surfaces.”¹² Moisture and friction are often responsible for the superficial breakdown of the skin in the sacral area, where incontinence associated dermatitis (IAD), a form of contact irritant dermatitis, is often misdiagnosed as a pressure ulcer.

Patient-centered Concerns¹⁸

Pain is often underestimated by wound care providers. Controlling pain promotes wound healing as well as renders patients more comfortable. Pain can be either nociceptive (gnawing ache, tender, and throbbing) stimulus dependant or neuropathic (burning, stinging, shooting, and stabbing) non-stimulus dependent. The former can be treated with the WHO’s pain ladder, starting with acetylsalicylic acid and nonsteroidal anti-inflammatory drugs and progressing to weak and stronger narcotic agents. Short acting drugs are used for initial dosing and breakthrough with longer acting agents for sustained and adequate pain control. Neuropathic pain can be spontaneous and is best controlled with tricyclic compounds high in anti-noradrenaline activity (e.g., nortriptyline or desipramine 10-30 mg at night, titrating higher if required) or anti-epileptic agents (e.g., gabapentin, pregabalin, or carbamazepine). Pain can also be minimized at dressing change with modern, easily removable dressings featuring soft silicone rather than traditional adhesive products.

Odor from a wound dressing is often concerning to patients and may indicate the need for treatment against gram-negative or anaerobic bacteria.

Smoking can decrease cutaneous blood flow by as much as 40%, inducing ischemia and impaired healing.¹⁹ Smoking one cigarette creates a vasoconstrictive effect for 90 minutes.²⁰

Bed rest resulting in physical and mental deterioration can be one of the most harmful strategies for the treatment of pressure ulcers.²¹ The facilitation of daily living activities will help promote a return to normal function.

Classification of Pressure Ulcers2

Pressure ulcers previously identified as grades or levels are now known as categories (outlined in Table 2). It is worth noting that the NPUAP considers suspected deep tissue injury (sDTI) and unstageable ulcers as a separate category, whereas the EPUAP designates both conditions as category 4.

A sDTI is characterized by a purple or maroon localized area of intact skin that may feature a blood filled blister due to damage of the underlying soft tissue from pressure and/or shear. Not all sDTIs subsequently ulcerate or breakdown, as they can selfresolve.

Location and Size

It is important to document the location and size of the wound. This facilitates objective assessment of progress or deterioration, especially when several care providers are involved with patient care. Wounds should be measured at the longest length and then the widest width at right angles to the measured length. Depth can be measured with a cotton tip applicator or wooden stick, where the deepest depth is measured a notch should be made on the disposable measuring instrument, and then the length should measured.

Arterial Insufficiency

Heel ulcers, although triggered by pressure, may be due in large part to lower limb arterial insufficiency.⁶

Treatment6

Local Wound Care

Gently cleanse wounds with low-toxicity solutions, i.e., saline, water, or acetic acid (0.5-1.0%). Wounds should not be irrigated when seepage of the solution is not visible or retrieval (or aspiration) of the irrigation solution is not possible. Under these conditions, use compresses applied with forceps on gauze ribbon as an alternative.

Debridement

Debridement can be accomplished surgically with scalpel, curette, or scissors. Sharp techniques may help remove bacterial burden on the surface of the wound, particularly when it is arranged in biofilms. Autolytic debridement is often facilitated with dressings (e.g., calcium alginates, hydrogels or hydrocolloids). Enzymatic (e.g., collagenase) or biological debridement with maggots are additional alternatives.

Moisture Balance

Achieving optimal moisture balance is essential in wound healing, which promotes new tissue growth by encouraging cellular proliferation and collagen formation.²² Moisture balance dressings are listed in Table 3 along with their autolytic debridement properties.

Infection

Bacteria can critically colonize wounds, leading to stalled healing. Critically colonized wounds can be identified with the presence of any three clinical signs in the mnemonic NERDS (non-healing, exudate increase, red friable or easily bleeding granulation tissue, new slough or debris on the wound surface, and smell).²³

Topical antimicrobials for healable wounds include silver dressings (combined with foams, alginates or hydrogels, as well as grid or cloth-like structures), PHMB foam and gauze, iodine (cadexomer iodine or povidone iodine), and honey (alginate, hydrogel or hydrocolloid).

The mnemonic STONEES (size increase, temperature of surrounding skin elevated, os-probing or exposed bone, new satellite areas of breakdown, erythema and/or edema = cellulitis, exudate increase, and smell),²¹ indicate infection that may be superficial, deep, or both, particularly if increased exudate and smell are present. Treatment with systemic antibiotics is required in these situations. The choice of antibiotic should preferably be based on bacterial swab results. Wounds that have been present for >4 weeks or if the patient is immunocompromised require antimicrobial coverage for gram-positive, gram-negative and anaerobic organisms. Osteomyelitis (OM) must be considered as a complication of pressure ulcers, especially if the ulcer probes to bone or the bone surface is rough, gritty or contains bone fragments. Supporting evidence for OM can be simply achieved by X-ray or MRI in some cases, along with elevated sedimentation rate (>40 mmHg/h) may be helpful in making this determination. Positive parameters should be followed and corrected prior to stopping systemic antibiotics.

Inflammation

Persistent inflammation due to excess harmful cytokines (e.g., matrix metalloproteinase 9) can result in delayed wound healing. This can be treated topically with dressings containing silver, collagen, oxidized regenerated cellulose, or ibuprofen.

Edge Effect

If the cause of a healable wound has been corrected and patientcentered concerns are addressed (including receiving optimal local wound care), but healing is stalled, advanced therapies can be considered. The edge effect refers to the cliff-like edges of a wound that is often seen with stalled healing, which contrasts the tapered edges and peripheral rim of purple new epithelium of a healing wound. If a wound does not exhibit a 30% reduction by week 4, it is unlikely to heal by week 12.⁶

Advanced Therapies

There is RCT evidence of advanced therapies in pressure ulcers, including electrical stimulation and therapeutic ultrasound.²⁴ Surgery is also considered when deep ulcers have bone, muscle or fascia base, and granulation tissue involvement, or healing cannot be easily stimulated with local measures. Surgery is often a major procedure that is accompanied by a structured rehabilitation program to prevent dehiscence. Some patients with heel pressure ulcers and peripheral vascular disease may benefit from hyperbaric oxygen therapy. Additionally, there may be a role for negative pressure wound therapy when a healable wound is stalled with excessive exudate.

Conclusion

Most pressure ulcers can be prevented, but not all can be avoided. A comprehensive assessment and treatment of PrUs can be completed with the wound bed preparation paradigm (Figure 1) outlined in this article. These assessments and interprofessional collaboration are important for the early identification and optimal PrU treatment. Local ischemia or incontinence associated dermatitis are often misdiagnosed as PrUs. Coordinated PrU treatment needs to combine an awareness of appropriate surfaces, turning schedules, correction of shear, and implement strategies for adequate protein intake/correction of nutritional deficiencies, enhanced mobility, manageable pain levels, and improved activities of everyday living. Empowering patients and their circle of care are key factors to treatment adherence and successful program outcomes.

Figure 1: Wound bed preparation for the prevention and treatment of pressure ulcers

References

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