Pressure Injuries: A Comprehensive Introduction

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Pressure Injuries: A Comprehensive Introduction

Pressure injuries, or bedsores, are incredibly pervasive chronic wounds that can be challenging and costly to treat. According to the Agency for Healthcare Research and Quality, over 2.5 million Americans develop pressure ulcers each year, particularly those in the underserved geriatric population. Understanding the development of pressure ulcers is a critical component of effective patient care, as these often-preventable wounds can significantly diminish patient quality of life.

To spread awareness about pressure injuries and their prevention and treatment considerations, the experts at Vohra
Wound Physicians have put together some helpful information about these wounds, including an overview of proper pressure injury staging using MDS 3.0, for care providers and physicians.

Editor’s Note: Physicians interested in learning more about a career in wound care are invited to explore our open opportunities. Click here to learn more.

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Pressure Injury Overview

Pressure injuries form when pressure or shear is applied against skin for a prolonged duration. This typically occurs over a bony prominence such as the scapula, sacrum, heel, shoulder, or elbow. However, pressure ulcers can also occur in other areas, such as on a body part that is in a cast or covered by a medical device. 

To prevent the development of these wounds, it’s important to understand pressure injury risk factors and stages of severity, as well as why they most commonly affect geriatric patients.

Pressure Injury Development

Although pressure ulcers can occur anywhere, they most commonly arise on bony prominences that are used for weight support. For example, if a patient lies in bed, body parts such as their shoulder blades, elbows, knees, ankles, feet, and heels are supporting their body weight.


Recognizing pressure injury development over these areas is particularly important since the bone can act like a tourniquet and cut off the blood supply, which can cause tissue death. Care providers must also pay attention to the skin covered by orthopedic devices, braces, slings, and casts, as these can all put pressure on the skin. 


The effect of surface pressure on tissue is dependent upon the magnitude and duration of applied pressure. The longer the duration, the smaller the magnitude necessary to cause a pressure ulcer; conversely, at high magnitude, these ulcers can be formed within a short time.

Pressure Injury Risk Factors

Since pressure injuries result from prolonged tissue pressure, they typically affect those that spend significant periods of time in bed or in a wheelchair. This includes the elderly and those who are immobilized or hospitalized due to illness or injury. Although these groups are most susceptible to these wounds, there are other factors to consider when assessing a patient’s risk for pressure injury.

If a patient has impaired sensation, they may not recognize when pressure is being applied to their skin and thus won’t adjust their positioning. For example, diabetics with neuropathy may not feel pain signals appropriately. This can lead them to develop pressure injuries, commonly on the feet. Other at-risk groups include those with urinary or fecal incontinence, those who are malnourished, and those with limited or impaired mobility.

Although the elderly population is most vulnerable to pressure injury development, this chronic wound can also affect young people. Patients of any age that have conditions such as multiple sclerosis, spina bifida, spinal cord injuries, bad injuries from a car wreck, or other traumas can lead to the development of pressure injuries.

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Pressure Injury Stages

Pressure injuries are classified into four stages of increasing severity. The later the stage of the injury, the more dangerous and difficult to treat it becomes, so identifying these wounds early-on is important. These stages proceed as follows:

Stage 1: In Stage 1, pressure injuries do not display breaks or tears in the skin. In this stage, the skin may appear inflamed or discolored and will not blanch in response to pressure. This is common in localized areas over bony prominences. 

Stage 2: A Stage 2 pressure injury is a very partial injury. In this stage, the skin displays superficial damage and may have a blister-like appearance with an area of open epidermis. There is no evidence of slough. Since the skin has various thicknesses throughout the body, the Stage 2 classification does not depend upon the injury’s depth, but rather how much the injury has extended through the dermis. 

If a pressure injury extends through the dermis, it has progressed past Stage 2. On a place with thin skin, such as the face or inner thigh, this may not be very deep, whereas on a place with thicker skin, such as the back, this will extend deeper.

Stage 3: In Stage 3, the wound displays full-thickness tissue loss including the dermis and epidermis. It deepens into the subcutaneous tissue and the fatty layer of the skin is visible. The wound may include tunneling or undermining as well as slough or necrotic tissue. At this stage, the wound does not disrupt the muscle fascia or anything below it.

Stage 4: A pressure injury is considered Stage 4 if it extends beyond the subcutaneous fat layer. At this stage, there is full-thickness tissue loss involving the epidermis, the dermis, and the subcutaneous tissue. Muscle, fascia, bone, ligaments, or other underlying structures are likely exposed. The injury is also highly susceptible to infection and may have areas of necrosis or eschar present in the wound bed.

Pressure Injuries in the Geriatric Population

Although pressure injuries can affect patients of many ages and circumstances, the majority occur in geriatric patients due to a number of age-related risk factors. For example, elderly patients tend to be immobilized more frequently due to illness or injury, leading to prolonged skin pressure. 

They also have more concomitant medical conditions such as diabetes, high blood pressure, kidney problems, and peripheral arterial disease. To treat these conditions, they may be prescribed medications that adversely affect the skin, such as steroids, chemotherapy drugs, gout drugs, or arthritis drugs. Even without comorbidities or skin-damaging medications, skin loses integrity and grows thinner as people age, making geriatric patients more susceptible to skin injuries such as breaks and tears.

Elderly patients also have higher rates of urinary and fetal incontinence, causing improper skin moisture and increasing the risk of infection. They also experience dehydration and poor nutrition more frequently than younger people and have slower metabolism, which can impede healing.

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Pressure Injury Considerations

When seeking to treat pressure ulcers, the primary consideration is pressure redistribution. This includes regularly repositioning immobilized or at-risk patients, preventing undue stress or friction on the skin, and avoiding pressure on bony areas. Patient repositioning and the use of support surfaces is the most effective way to prevent or assist in the healing of pressure injuries.

Pressure Redistribution

Pressure redistribution refers to how pressure is removed from a site of potential injury and is redistributed over a broader — or more diverse — area. For example, if a heel rests on a 1×1inch area to support a leg weighing 30 pounds, there are 30 pounds per square inch of pressure on the heel.

However, if the leg instead rests on a 4×6 pillow, that 30 pounds of pressure is redistributed over 24 square inches. This reduces the pressure at any given point on the leg to 1.25 pounds per square inch — a significant difference that can prevent the development of a pressure injury.

Conforming surfaces, such as pillows, distribute pressure over a larger area. This reduces both the magnitude of pressure and the shear over bony areas. When seeking to redistribute pressure to prevent the development of a pressure injury, be sure to consider the following factors:

  • Immersion: How far will a bony prominence go down into the mattress or cushion?
  • Envelopment: How well will a surface conform to irregularities laying on it?
  • Pressure gradient: Will pressure redistribute over a wide area so that it is alleviated and absorbed?

Although repositioning and pressure redistribution are important parts of effective pressure injury prevention, it is also important to consider friction, shear, temperature, and moisture.

Friction and Shear Control

Pressure injuries occur when shear is applied against skin, and friction is a factor in the production of shear forces. When a patient lies in bed, gravity wants to pull their body down the sloping bed. Friction, on the other hand, is the force that seeks to prevent the body from sliding. 

When the head is elevated, pressure injury occurs as a result of friction working against gravity. This creates sheer force that leads to tissue damage. Performing regular patient repositioning and assisting patients when moving in bed can prevent injury due to friction and shear. When conducting these movements, using a lift sheet can keep the patient’s head at a relatively low angle to prevent friction.

Temperature and Moisture Control

Temperature and moisture are two important factors in the development of pressure injuries, as these factors can cause skin weakening and increase the risk of tissue damage due to friction and shear.

Prolonged exposure to moisture impacts skin resilience and causes maceration, or skin softening, making skin prone to breakdown. Moisture can be caused by factors such as perspiration, incontinence, edema, and wound exudate.

Increased temperature can also be problematic. For every 1.8-degree Fahrenheit change in the body, there is a 10% increase in the use of resources such as O2 and nutrients. This change can impair oxygen delivery, sensation, and lymphatic function.

To prevent improper skin moisture and temperature, patients should undergo regular skin care. Skin should be cleansed, emolliated, and moisturized with non-irritating, pH-balanced products. Skin should also be assessed for excessive dryness or moisture, color changes, edema, and pain or discomfort.

Choosing Support Surfaces

Support surfaces are valuable components of effective pressure injury care. They can be used to assist in patient repositioning, pressure redistribution, and temperature and moisture avoidance.

Some factors to consider when choosing a support surface to prevent pressure wounds are: 

  • Product reputation: Is the support surface produced by a reputable company? Is it highly reviewed?

  • Product safety: Have there been any reports of accidents or injury resulting from use of the support surface? Is the product flammable?

  • Infection control: Can the surface be easily washed or cleaned? Does it trap bacterial organisms?

  • Patient circumstance: Repositioning and support surface use can be uncomfortable or even painful. When determining how and when to use these tools, it’s important to weigh comfort versus effectiveness as it relates to a patient’s life expectancy.

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Video Demonstration: Pressure Injury Staging Under MDS 3.0

One valuable way to expand your knowledge of pressure ulcers is by hearing from experienced physicians. Consider this demonstration of an important aspect of pressure injury care: the staging of wounds.

In this video, Dr. Japa Volchok, DO, discusses the proper staging of wounds such as pressure ulcers using the Minimum Data Set (MDS) 3.0 convention. Dr. Volchok provides in-depth explanations for each wound stage and explains why proper
staging is critical for wound documentation.


This demonstration is performed by a trained wound care physician for educational purposes only and should not be tried at home.

Understanding the MDS 3.0

The Minimum Data Set (MDS) 3.0 assessment is a staging convention tool used to screen all residents in Medicare- or Medicaid-certified long-term care facilities. This assessment includes resident diagnoses and treatments and identifies potential care problems. This helps identify patient risk and informs the development of individualized treatment plans.

One important component of the MDS 3.0 is numerical staging for pressure ulcers. The wound stages are based upon the depth and description of soft tissue damage and are helpful in predicting healing times. Staging under MDS 3.0 has some differences when compared to the older MDS 2.0 staging system and the more commonly known National Pressure Ulcer Advisory Panel staging. 

The MDS 3.0 staging convention uses four stages to classify wounds, plus an additional stage for unstageable wounds. MDS 3.0 does not allow for reverse or back-staging of wounds. These stages inform effective wound documentation, treatment plans, and healing time estimates. They also prove helpful when addressing concerns during CMS state surveys.

Video Description

In this video, Dr. Volchok explains the staging and measurement of a pressure ulcer using an artificial tissue model. He discusses the pressure injury’s progression from stage one through stage four and indicates the differences in wound damage.

Stage 1


When demonstrating stage one, the black dotted line in the video demo shows the outline of a wound that, when palpated and released, does not show any change in the erythema. This is non-blanchable erythema consistent with a Stage 1 pressure ulcer. After identifying a stage one pressure injury, the wound is measured. Here, the wound is 3 centimeters long and 1.5 centimeters wide. The epithelium is intact, thus indicating a Stage 1 pressure ulcer with no measurable depth.

Stage 2 and 3


At Stage 2, pressure injuries present as a shallow ulcer with an area of open epidermis. The ulcer may be serum fluid-filled or bloody fluid-filled. If the underlying tissue with a blister shows evidence of deep tissue injury or if there is significant surrounding deep tissue injury, this should be staged as an unstageable wound secondary to deep tissue injury (DTI).

In this model, Dr. Volchok demonstrates a Stage 2 on the right side of the screen and a Stage 3 on the left side of the screen. The Stage 2 pressure ulcer on the right side of the screen involves loss of the epidermis and dermis. The Stage 3 pressure ulcer on the left side of the screen involves deeper subcutaneous tissue and may also contain slough or necrotic tissue. Neither a Stage 2 wound nor a Stage 3 extend into the fascia or muscle level, and there is no involvement of bone or tendon.

Stage 4


A Stage 4 pressure ulcer involves full thickness tissue loss involving the epidermis, the dermis, and the subcutaneous tissue. It includes exposed muscle, fascia, bone and other underlying structures such as tendons. There also may be undermining and tunneling, and areas of necrosis or eschar may be present in the wound bed.

In this model, you can see a Stage 4 pressure ulcer. You can tell that the wound is fairly deep and has extended to the level of muscle, as there are muscle fibers running across the length of the wound. You can actually see those being held by the forceps. Just below the muscle fibers, there is an area of exposed bone.

Depending on the anatomic location on the body, the depth of the wound can vary dramatically. For example, subcutaneous tissue over an area such as the ankle and the lateral malleolus or on the hands can be fairly thin. Conversely, an area such as the heel or the back can have significant subcutaneous tissue before you reach the level of muscle or fascia. Due to these differences in skin thickness, the level of tissue damage dictates the stage, not the actual depth of the wound.

If the bed of this wound was obscured by necrotic tissue, it would be classified as an unstageable wound. However, since it is clear that there are muscle fibers and bone present in the base of the wound, this is categorized as a Stage 4 pressure injury. This injury also has necrotic tissue present.

If the necrosis is completely removed from the unstageable wound using debridement, we see that the wound extends to the level of muscle fibers. This would then be categorized as a Stage 4 pressure ulcer. 

Unstageable Wounds

The final category of staging under MDS 3.0 includes unstageable wounds. There are several reasons that a wound may be unstageable. For example, if there is suspected deep tissue injury (DTI), the wound should be staged as unstageable because DTI often progresses to a much deeper extent than seen on the wound’s surface. Other signs of DTI include color change, bogginess or tenderness. 

This wound model has been developed to demonstrate a wound that has suspected DTI and is thus unstageable. The dotted line demarcates the edge of the wound. A correct wound assessment would involve measuring the length of 3.5 centimeters by the width of 2.5 centimeters.

Another reason to stage a wound as unstageable is if necrosis covers the full extent of the wound or if eschar prevents visualization of the wound’s entire depth and the identification of anatomic structures. 

Under MDS 3.0, there is also a category for unstageable wounds secondary to a non-removable device. This would be appropriate for staging a wound that was under an unremovable cast or medical device. This does not include wounds that are covered by negative pressure.

Under MDS 3.0, only pressure ulcers are staged with this convention. As a note, diabetic foot ulcers are recorded under a separate category and are not staged using the aforementioned staging structure.

The Role of Pressure Injuries in Wound Care

Pressure injuries are an incredibly common chronic wound that are often preventable. By understanding the development of these wounds and strategies for their prevention, healthcare providers can significantly improve their patients’ quality of life and avoid challenging and costly treatments. 

At Vohra Wound Physicians, we believe that there are no wounds that can’t be healed. By expanding your knowledge of pressure injuries, you can prevent and heal chronic wounds that affect millions. To learn more about
practicing wound care you can read about types of procedures performed by Vohra physicians, a day in the life of a wound care physician, and why many doctors are transitioning to wound care.

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Author: Janet S. Mackenzie, MD, ABPS, CWSP, AAGP

Janet S Mackenzie MD, ABPS, CWSP, AAGP is the Chief Medical Officer at Vohra Wound Physicians. She has been with the company since 2013 and has almost 30 years of wound care experience as both a plastic surgeon and a wound care specialist. After obtaining a Master’s degree in Education, she obtained her Medical Degree from the University of Pennsylvania Perelman School of Medicine. She trained in general surgery at Dartmouth Hitchcock Medical Center and plastic surgery at McGill University. She is board certified by the American Board of Plastic Surgery, the American Board of Wound Management, and the American Board of General Medicine, and is a Certified Wound Specialist Physician (CWSP).

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