Pressure Injuries
The term decubitus wound, commonly called a bedsore in the past, comes from the Latin word for lying down (cubare). For many years, these wounds were called pressure ulcers; however, an ulcer is defined as a break in an epithelial surface, such as skin or mucosa.1 The modern term is pressure injury (PI), which includes stage 1 and deep tissue pressure injury (DTPI), neither of which is a break in the skin (Figures 1, 2, 3, 4, 5, 6, 7, 8, and 9). A PI is an injury to the skin and/or subcutaneous tissue, localized over a bony prominence, resulting from pressure, including pressure from medical devices.2 A DTPI is defined as “intact or non-intact skin with localized area of persistent nonblanchable deep red, maroon or purple discoloration, or epidermal separation revealing a dark wound bed or blood-filled blister.3 By convention, it also includes shear or abrasion injuries over a bony prominence. A shear injury is a parallel force on the skin, whereas a PI is a vertical force. Both cause the blood supply and lymphatic flow to be damaged, with subsequent hypoxia and tissue death (infarction). Dead tissue quickly becomes infected, which is a common and significant reason why PIs often worsen.
A pressure injury is one of several common wound types (Table). The common bony prominence areas where PIs can occur are the 1) sacrum and heels due to lying flat for an extended period, 2) ischial tuberosities due to sitting in a wheelchair for long periods, 3) greater trochanters (hips) and lateral malleoli (outside of the ankle), and 4) skin under a splint or a cast, especially at the top and bottom of the splint or cast. Pressure injuries also occur at the occiput (back of the head), scapula, elbows, behind the ears in a patient with a nasal cannula, and on the lips in a patient with an endotracheal tube.
There is a difference between a PI on the sacrum and incontinence-related skin damage, which is often called moisture-associated dermatitis. Dermatitis is inflammation of the skin from any cause. This includes incontinence because urine and stool are irritating to the skin. In addition, moist skin becomes macerated and breaks down more easily than dry skin. Incontinence-related skin damage usually consists of multiple open skin lesions on a background of inflamed skin, often complicated by a fungal infection. It may be over a bony prominence. It generally can be prevented with barrier cream or ointment to the buttocks applied after diligent toileting care.
RISK FACTORS
There are many risk factors for PIs, and most patients in the hospital or a nursing home are at some level of risk. By far the most common risk assessment tool is the Braden scale, which has 6 subscales: sensory perception, moisture, activity, mobility, nutrition, and friction.4 The highest score is 23 (no risk), and the lowest score is 6 (severe risk). There are many other risk factors to consider, including age, incontinence, obesity, malnutrition, and comorbid conditions.
The commonly used semi-Fowler position (head of the bed elevated to 45 degrees) creates friction and pressure on the sacrum and coccyx5 and is, therefore, a significant risk factor of PIs. This position may be required medically, but in the author’s opinion, the sacrum and coccyx should be protected with foam dressings.
A risk assessment score has no logical purpose in a patient who already has the condition. Such a patient already has a 100% risk, in the same way that a patient in an intensive care unit who has had a heart attack has a 100% risk of heart attack, regardless of how low the perceived risk was prior to the event. Patients receiving a care plan based solely or mostly on their Braden risk assessment, which may be interpreted as low risk even if the patient already has a PI, is a frequent problem. A low-risk care plan may not include essential care, such as frequent turning and repositioning, offloading heels, and using barrier creams, all of which are critical to treating the existing PI.
Even if a patient does not have a PI, a risk assessment should be performed on admission to a hospital or nursing home and be repeated frequently depending on the facility protocol. Reassessment can be done every shift in a critical care unit, every 48 hours in an acute medical-surgical unit, weekly or quarterly in a nursing home, or for any significant change in status. To the best of the author’s knowledge, there are no good studies on this. However, the above is an established standard of care for any patient in a health care facility.
Serum albumin is frequently used to measure nutritional status but is not a good marker for nutrition. Many people have low serum albumin levels because they are older, less active, and have chronic comorbid conditions, but their nutritional status is healthy. Conversely, people can be malnourished and have a normal or near-normal serum albumin level.6 The author prefers to use unintentional weight loss as a marker for poor nutrition, with an attendant increased risk of PIs and lack of healing.
STAGING
There are 6 stages of pressure injury: 1 to 4 plus unstageable and DTPI.2 Depth cannot be measured if a wound is covered by eschar (a hard, dark scab) or slough (dry, dead cells, including dead bacteria); such a wound is unstageable. Unstageable wounds are always stage 3 or stage 4, because stage 1 and stage 2 do not have eschar or slough. The stage 3 or 4 diagnosis cannot be made until the wound has been debrided and cleaned so that the wound base is visible.
A stage 1 PI is a red lesion that is nonblanchable. That means that if pressure is applied, the lesion does not blanch (ie, turn pale) because there is subcutaneous bleeding. It is the first indicator of tissue destruction and needs to be treated with appropriate protective, dressings such as a foam dressing and possibly a secondary protective dressing such as an ABD pad. The PI should resolve within 36 hours if the pressure is relieved.
A stage 2 wound is superficial from partial loss of the dermis. It may present as a blister or an abrasion. Again, it needs to be treated with pressure relief and an appropriate dressing(s). Generally, it will heal within 7 to 10 days like a normal blister, unless it gets infected or traumatized with continued pressure.
A stage 3 wound is a full-thickness injury down into the subcutaneous fat. These wounds often take several weeks to heal. They often get infected easily but can be treated with topical antimicrobials. Increasingly, full-thickness wounds are also treated with negative pressure wound therapy.
A stage 4 wound is a full-thickness injury that includes damage to underlying muscle, bone, or tendon. Bone frequently gets infected, causing osteomyelitis. Osteomyelitis often is incurable and may result in amputation of a limb or death due to sepsis.
A DTPI is essentially a bruise. It may be severe or mild, and it may break open at the skin level. In the author’s experience, if the pressure is relieved from the darkened area of skin, a DTPI will usually heal unless the overlying skin has been significantly traumatized.
This article was written to coordinate with a video lecture for Health Volunteers Overseas, Washington, DC. Dr Davey is a mostly retired wound physician with more than 24 years of practice treating many different types of wounds at the HCA Edward White Hospital Wound and Hyperbaric Medicine Center in St. Petersburg, FL. He can be contacted at drchrisdavey@outlook.com and welcomes all feedback. The opinions and statements made here are not necessarily those of Wound Management & Prevention or HMP Global. This article was not subject to the Wound Management & Prevention peer-review process.
REFERENCES
1. Ulcer. Merriam-Webster online. https://www.merriam-webster.com/dictionary/ulcer
2. European Pressure Ulcer Advisory Panel, National Pressure Injury Advisory Panel, Pan Pacific Pressure Injury Alliance. Prevention and Treatment of Pressure Ulcers: Quick Reference Guideline 2019. Haesler E, ed. EPUAP/NPIAP/PPPIA; 2019.
3. Salcido RS. Myosubcutaneous infarct: deep tissue injury. Adv Skin Wound Care. 2007;20(5):248–250. doi:10.1097/01.ASW.0000269303.40941.7e
4. Bergstom N, Braden BJ, Laguzza A, Holman V. The Braden scale for predicting pressure sore risk. Nurs Res. 1987;36(4):205–210.
5. Rappl L. Management of pressure by therapeutic positioning. In: Sussman C, Bates-Jensen BM, eds. Wound Care: A Collaborative Practice Manual for Healthcare Professionals. Lippincott Williams & Wilkins; 2007:374–404.
6. Ohwada H, Nakayama T, Kanaya Y, Tanaka Y. Serum albumin levels and their correlates among individuals with motor disorders at five institutions in Japan. Nutr Res Pract. 2017;11(1):57–63. doi:10.4162/nrp.2017.11.1.57
