Article Summary 
• Pressure injuries are caused by unrelieved pressure over a bony prominence leading to tissue death
• Pressure injuries can lead to pain, scarring, infection and possibly death
• Low mobility patients are at highest risk
• Assessments should be conducted daily for high risk patients
• A range of assistive devices may be used to offload pressure


Pressure injuries (PI), commonly known as pressure ulcers or pressure sores, may have serious consequences for patients and their families. Sequelae include pain, scarring and disfigurement, infection including cellulitis, sepsis and/or osteomyelitis, reduced quality of life and, in some cases, death.

In Australia the incidence of PI ranges between 13 to 37% depending on the care setting (Department of Health & Aging (DoHA), 2005). In the acute care environment, hospital-acquired PIs account for up to 67.6% of injuries identified (DoHA, 2005). In 2005 the annual cost of PIs to the health system was approximately 285 million dollars (DoHA, 2005). One stage 3 or 4 PI is estimated to cost up to $70,000 in health resources, not to mention the additional expense of litigation, which is becoming more common.

What is a Pressure Injury?
A PI is defined as damage to skin and underlying tissues due to unrelieved pressure directly over a bony prominence and/or as a consequence of shear and friction forces (Australian Wound Management Association (AWMA), 2012). Once sustained, PIs require intensive care and resources to assist healing and to prevent further trauma to the tissues.

Damage occurs when tissues and blood vessels are compressed between the point of pressure and bony prominence, for example over the hip, sacrum, heel or toes, elbow, scapula or shoulder. Decreased blood flow to the area deprives tissues of oxygen and vital nutrients. Local tissue ischemia, capillary thrombosis and occlusion of lymphatic vessels increase capillary permeability causing oedema. Cell and tissue death leads to tissue necrosis and damage progressively makes its way to the surface revealing an ulcer.

Risk Factors
All health professionals must become proactive and vigilant in conducting skin integrity assessment and in monitoring PI risk. Patients unable to independently reposition themselves in bed or whilst sitting in a chair are automatically at risk of developing a PI. Reduced mobility may be caused by spinal cord injury or neuro degenerative diseases such as multiple sclerosis and motor neuron disease; cerebral vascular accidents or stroke; acute illness;  bone fractures; traction and surgery. Risk increases with age (particularly over 60 years) and certain co-morbidities including sensory neuropathy and delirium, plus any condition that limits peripheral perfusion i.e. respiratory conditions such as severe asthma, COPD, pneumonia or a history of smoking; hypotension; anaemia, cardiovascular compromise; peripheral arterial and renal disease and cognitive impairment. However, reduced mobility and the inability to detect and respond to pressure are major risk factors.

While many factors have been mentioned in the literature, pressure is the only validated risk factor for PI development: a view supported by the current accepted definition of a PI as described in the Pan Pacific Clinical Practice Guideline for the Prevention and Management of Pressure Injury (AWMA, 2012). If your patient has an existing pressure injury or has reduced mobility then an equipment upgrade and implementation of prevention strategies must be considered: repositioning; regular skin inspection and reassessment of risk; pressure relieving or offloading devices; aids that assist patients to mobilise; ensuring optimal hydration and nutrition; and communication with the interdisciplinary team and at clinical handover is essential to ensure both continuity of care and risk reduction.

Prevention of pressure injuries should be of the highest priority with both a skin and pressure injury risk assessment conducted for every patient on admission. Skin assessment requires inspection of the patient’s skin for existing pressure injuries or other skin conditions that may reduce the resilience of skin and underlying soft tissues to pressure and/or shear and frictional forces. As resilience decreases, the ability to withstand pressure also decreases. Skin breakdown, bruising or the presence of other skin conditions (thin, dry or dehydrated skin) may increase your patient’s risk. Patients on medications such as cytotoxics, long term steroids or those prescribed for autoimmune diseases such as rheumatoid arthritis and lupus are also at risk.

Staging
Correct staging of a PI is essential to proper management. If your patient has reddened or discoloured skin over a bony prominence that stays red or discoloured when pressed, chances are they have sustained a stage 1 PI. If the area blanches i.e. becomes lighter when pressed this can be considered as a pre-injury condition. Referred to as blanching erythema or reactive hyperemia, at this point no damage has been sustained. However it is important to relieve the pressure to the affected area and implement PI prevention strategies, including conducting a risk assessment, and to monitor the patient closely in order to prevent further damage. Blanching erythema may take up to 72 hours to resolve but generally any redness or discolouration will return to normal colour within 30 minutes to an hour. It is important to re-check for blanching or capillary refill to ensure there is no damage to the affected area. If redness fails to maintain capillary refill (non-blanching erythema with intact skin) this indicates tissue death has occurred and the patient has sustained a stage 1 PI. You must consider an equipment upgrade (pressure relieving mattress), more frequent repositioning and the use of assisting devices to offload pressure and/or reduce shear and friction. 

A stage 2 PI presents as erosion of the superficial skin layers (epidermis and dermis) without penetration into the sub-dermal fat layer (Australian Wound Management Association (AWMA), 2012). A heel blister filled with clear serous fluid that allows a visual of the underlying tissues may also be categorised as stage 2. Stage 3 and 4 PI are more serious and confer considerable pain and suffering to the patient. A stage 3 PI transcends the superficial layers of the skin and penetrates into the sub-dermal fatty layer. With stage 3 injuries there is no exposure of deeper structures such as muscle, tendon or bone (AWMA, 2012). Stage 4 PI are full thickness injuries exposing the deeper structures. Slough (yellow necrotic tissue) or eschar (a black leathery necrotic covering) may also be present. Stage 3 and 4 PI may also have undermining or tunneling due to the separation of the deeper muscle tissue from the dermal layer due to shearing forces (AWMA, 2012). Some injuries are impossible to stage as the base of the wound cannot be seen. While these injuries are unstageable the damage is deeper than the upper dermal layers, consequently they must be categorised as at least a stage 3 PI but may possibly be a stage 4. Black heels are an example of an unstageable PI.

Assessments and Management
Skin and PI risk assessments should be conducted at least weekly for those not at risk or when the patients’ health status deteriorates and pre- and post-surgery. For those who are at risk re-assessment should be conducted at least daily or more frequently if warranted. Assistive devices to offload pressure include specialised mattresses, monkey bars, bed rails, leg gutters, pillows, Podus boots, bed cradles, and Roho seating cushions. Patient and family/carer education regarding PI development, how to inspect skin and what to look for, and ways to minimise risk is an essential component of prevention. Often patients remain at risk on discharge from hospital and once a PI develops the affected area remains vulnerable for up to two years post-healing.

Therefore, in summing up, the prevention of PIs in vulnerable people is everyone's business. Prevention requires a health system-wide effort and a proactive attitude from all health professionals that is born from an empirical understanding of the deleterious consequences that PIs confer, particularly stage 3 and 4. Pressure injury prevention requires regular assessment of the patient’s skin and PI risk; clear documentation of assessment outcomes and management plans implemented in the patient’s care plan and health medical record; and communicating those plans at clinical handover. Timely referral to allied health services including the dietitian and occupational therapy in addition to the acute pain service (for adequate pain management), discharge planner and wound care specialist may also be necessary for interdisciplinary management and service provision post-discharge. This will not only ensure continuity of patient care but optimise patient outcomes.



References:
Australian Government Department of Health and Aging (DoHA). (2005). Trial of a system for the prevention and management of pressure ulcers. Accessed 23/07/2012 from: http://www.health.gov.au/
Australian Wound Management Association (AWMA). (2012). Pan Pacific Clinical Practice Guideline for the Prevention and Management of Pressure Injury. Cambridge Media Osborne Park, WA.  ISBN Online: 978-0-9807842-3-7.