Pressure Injuries

Original Editor - Jayati Mehta

Top Contributors - Jayati Mehta, Kim Jackson, Naomi O'Reilly, Lucinda hampton, Adam Vallely Farrell, Ewa Jaraczewska, Tony Lowe, Rucha Gadgil, Tarina van der Stockt, WikiSysop, Vidya Acharya, Lauren Lopez, Samuel Winter, Jess Bell, Robin Tacchetti and Stacy Schiurring

Introduction

"Skin damage that occurs as the result of pressure should be referred to as pressure injury rather than pressure ulcer, because skin damaged from pressure can be intact or ulcerated. "

Pressure injuries are skin and soft tissue injuries that form as a result of constant or prolonged pressure exerted on the skin.

These injuries

• Occur at bony areas of the body such as the ischium, greater trochanter, sacrum, heel, malleolus (lateral more than medial), and occiput.
• Mostly occur in people with conditions that decrease their mobility making postural change difficult.

** Wheelchair users are at risk for pressure injuries in the greater trochanters, ischial tuberosities and sacrum/coccyx.

Etiology

The development of pressure injuries is complex and multifactorial.

• Loss of sensory perception, locally and general impaired loss of consciousness, along with decreased mobility, are the most important causes that aid in the formation of these injuries (patients are not aware of discomfort hence do not relieve the pressure).

Both external and internal factors work simultaneously, forming these injuries.

1. External factors; pressure, friction, shear force, and moisture
2. Internal factors; fever, malnutrition, Anaemia, and endothelial dysfunction speed up the process of these lesions.

The dysfunction of nervous regulatory mechanisms responsible for the regulation of local blood flow is somewhat culpable in the formation of these injuries:

• Prolonged pressure on tissues can cause capillary bed occlusion and, thus, low oxygen levels in the area
• Over time, the ischemic tissue begins to accumulate toxic metabolites.
• Subsequently, tissue ulceration and necrosis occur.

Risk factors include: neurologic disease and disorders, cardiovascular disease, prolonged anesthesia, dehydration, malnutrition, hypotension, and patients undergoing surgery.

Epidemiology

Pressure injuries are a worldwide health care concern affecting tens of thousands of patients and costing over a billion dollars a year. The cost of preventing and managing pressure injuries have increased significantly since 2008 with more than 2.5 million adults being affected in the United States. The estimated cost of hospital-acquired pressure ulcers alone is approximately $26.8 billion annually.

• Their management costs billions of dollars per annum, burdening the already scarce health economy.
• Elderly patients are more prone to sacral pressure injuries
• Two-thirds of injuries occur in patients who are over 70 years old
• Patients who are incontinent, paralyzed, or debilitated are more prone to getting them
• Individuals with spinal cord injury who use wheelchairs have a high risk of developing pressure injuries
• Patients with normal sensory status, mobility, and mental status are less likely to form these injuries because their normal physiologic feedback system leads to frequent physical positional shifts. .
• Data that shows 83% of hospitalised patients with injuries developed them within five days of their hospitalisation

Pathophysiology

Many factors contribute to the development of pressure injuries, but pressure leading to ischemia and necrosis is the final common pathway.

• Result from constant pressure sufficient to impair local blood flow to soft tissue for an extended period.
• External pressure must be greater than the arterial capillary pressure (32 mm Hg) to impair inflow for an extended time
• Greater than the venous capillary closing pressure (8-12 mm Hg) to impede the return of flow for an extended time.
• Tissues are capable of withstanding enormous pressures for brief periods, but prolonged exposure to pressures just slightly above capillary filling pressure initiates a downward spiral toward tissue necrosis and ulceration.
• The superficial dermis can tolerate ischemia for 2 to 8 hours before breakdown occurs.
• Deeper muscle, connective tissue, and fat tissues tolerate pressures for 2 hours or less (probably because of its increased need for oxygen and higher metabolic requirements). 
• Often there is significant damage to underlying tissues while the epidermis and dermis remain intact.
• By the time ulceration is present through the skin level, significant damage of underlying muscle may already have occurred, making the overall shape of the ulcer an inverted cone.. 
• Friction caused by skin rubbing against surfaces like clothing or bedding can also lead to the development of injuries by contributing to breaks in the superficial layers of the skin.
• Moisture can cause injuries and worsens existing injuries via tissue breakdown and maceration

Complications

Complications of pressure injuries, some may be life-threatening, include:

• Cellulitis - Cellulitis is an infection of the skin and connected soft tissues. It can cause warmth, redness and swelling of the affected area. People with nerve damage often do not feel pain in the area affected by cellulitis.
• Bone and Joint Infections - An infection from a pressure sore can burrow into joints and bones. Joint infections (septic arthritis) can damage cartilage and tissue. Bone infections (osteomyelitis) can reduce the function of joints and limbs.
• Cancer - Long-term, non-healing wounds (Marjolin's ulcers) can develop into a type of squamous cell carcinoma.
• Sepsis - While sepsis is not a guaranteed outcome from a skin ulcer, infected pressure injuries can indeed lead to sepsis, particularly if poorly managed or if the infection becomes severe. The risk is substantial enough that it warrants careful monitoring and management of all pressure injuries, especially in high-risk populations.

Pressure Injury Staging

There are various stages of pressure injury, all of which classify the injury based on the depth of skin injury. Pressure injuries are categorised into four stages:

• Stage 1: Intact skin with nonblanchable erythema
• Stage 2: Partial-thickness skin loss with exposed dermis
• Stage 3: Full-thickness skin loss
• Stage 4: Full-thickness skin and tissue loss. There may be muscle, bone, tendon, or joint involvement.

• Unstageable Pressure Injury: The depth is unknown because slough or eschar obscures the extent of tissue damage.

Machine learning models show promise as decision support tools for pressure injury staging, particularly where clinical assessment falters (e.g. Stages 3-4, deep tissue injuries, and unstageable wounds). While healthcare professionals reliably identify early-stage injuries, accuracy drops substantially for complex cases, and emerging evidence suggests algorithmic assistance may improve diagnostic performance, especially for less experienced clinicians. These tools should be viewed as adjuncts to clinical judgement rather than replacements, with rehabilitation professionals requiring both strong foundational assessment skills and critical appraisal abilities to evaluate when algorithmic support meaningfully contributes to patient care.

Symptoms

As mentioned previously, pressure injuries can affect any part of the body that is put under pressure. They often develop gradually, but can sometimes form in just a few hours.

Early Symptoms

• Discolouration of parts of the skin- those with pale skin tend to develop red patches, while people with darker skin tend to get purple or blue patches
• Discoloured patches not turning white when pressure is applied
• A patch of skin that is warm, spongy or hard
• Pain or itchiness in the area affected

Later Symptoms

The skin may not be broken at first, but if the pressure injury gets worse it may form:

• An open wound or blister (Stage 2)
• A deep wound which reaches the deeper layers of the skin (Stage 3)
• A very deep wound that may reach the muscle and bone (Stage 4)

Clinical Presentation

The severity of pressure injury can be estimated by observing clinical signs. A progression from least tissue damage to most severe damage is presented here.

• The first clinical sign of pressure injury is blanchable erythema along with increased skin temperature. If pressure is relieved, tissues may recover in 24 hours. If pressure is unrelieved, non-blanchable erythema occurs.
• Progression to a superficial abrasion, blister, or shallow crater indicates involvement of the dermis.
• When full-thickness skin loss is apparent, the injury appears as a deep crater. Bleeding is minimal, and tissues are indurated and warm. Eschar formation marks full-thickness skin loss. Tunnelling or undermining is often present.
• The majority of all pressure injuries develop over six primary bony areas sacrum, coccyx, greater trochanter, ischial tuberosity, calcaneus (heel), and lateral malleolus.

Diagnosis

1. If an individual has a history of a period of immobility followed by the discovery of a warm, red, spot over a bony prominence, a pressure injury can usually be confirmed.
2. If the spot is unnaturally soft to the touch, sometimes referred to as “boggy,” this is enough evidence to suspect that damage is deeper than the epidermis.

The following tests may be performed :

• Blood Tests 
• Tissue cultures to diagnose a bacterial or fungal infection in a wound that doesn't heal with treatment or is already at stage IV.
• Tissue cultures to check for cancerous tissue in a chronic, non-healing wound.

Treatment / Management

Managing pressure injuries is complicated as there is no fixed treatment regime/algorithm.

Once a pressure injury has developed, there should be no delay in treatment, and management should start immediately.

• Treatment varies between site, stage, and associated injury related complications.
• The goal of all the various treatment options is to;
  • minimise the pressure exerted on the site of injury
  • minimise contact of the site of injury with a hard surface, decrease moisture, and to keep it as aseptic or least septic as possible.
• The choice of treatment options should be according to the stage/grade of the pressure injury, and what the purpose of the treatment should be (decreasing moisture, removal of necrotic tissue, controlling bacteremia).
• Prevention is clearly the best treatment with excellent skincare, pressure dispersion cushions, support surfaces and seat comfort.

Support surfaces decrease the amount of pressure on the wound. Support surfaces can be either static (e.g., air, foam, and water mattress overlays) or dynamic (e.g., alternating air overlay). Repositioning and turning the patient every two hours can also lessen pressure on the area, but some patients may require more frequent repositioning, while others may require less frequent repositioning.

• In some cases, urinary and faecal diversion may be necessary depending on the site of injury, being prone to urine or faecal contamination.
• Hydrocolloid dressings should be used.
• Good antibiotic cover decreases the risk of sepsis.
• The depth and severity of the injury determine whether surgical management may be required.
• Some evidence exists suggesting that hyperbaric oxygen therapy can help with wound healing, as it improves oxygenation in and around the area of the wound.

In Summary, treatment of pressure injuries has its basis in the following:

• Prevention of additional injuries
• Decreasing pressure on wound
• Wound management
• Surgical intervention
• Nutrition

Prevention

Patients and their family members should have a clear idea that preventing recurrence requires commitment and responsibility. They should

• Receive education on how to manage the condition in the hospital and as well as in their homes.
• Be familiar with warning signs like skin discoloration, ulceration, discharge, or a foul smell from the injury site and body areas with decreased or no sensation.

The patient should

• Move or turn every 2 hours; it could not be done by themselves, or they should ask someone to help them.
• Use air or water mattress in their homes.
• Have adequate food intake adequate and it should consist of a balanced and healthy diet.

Improving Patient Outcomes

The main goal is to prevent development of pressure injury by decreasing the pressure acting on the affected site.

This goal requires an interprofessional team, including primary care providers, wound care specialists, surgeons, specialty-trained wound nurses, physical therapists, and nurses aides.

• Physiotherapists should try to increase patient's physical activity, at appropriate level.
• Nurses provide care, monitor patients, and notify the team of issues. Nurses aides are often responsible for turning and repositioning patients.
• Air-fluidised or foam mattresses should be used, frequent postural changes, provision of adequate nutrition, and treatment of any underlying systemic illnesses.
• Debridement should take place to remove dead tissue that serves as the optimum medium for the growth of bacteria.
• Hydrogels or hydrocolloid dressing should be used, which aid in wound healing.
• Tissue cultures are necessary, so the most directed antibiotic can be administered, which can involve the pharmacist and the latest antibiogram data.
• The patient should be kept pain free by giving analgesics.
• Frequent follow-ups are an absolute necessity and a team approach to patient education and management involving the wound care nurse and wound care clinician will lead to the best results.