Pressure Ulcers

Definition of A Pressure Ulcer and Its Effect

by Marlon L Inestroza, BSET, RHIT MP

Date: 7/5/2017

Golden MedTools, Inc.

A pressure ulcer (also known as bedsore, decubitus, and pressure sore) is a skin-damaging diagnosis on certain areas of a human body. It is caused by resting in bed in a supine position without moving for an extensive period. What we don’t know is the detailed breakdown of how the pressure ulcer injures skin. Bedsores can happen to a person at any age resting in bed for a very long time; however, many affected patients include individuals who are age 65 and older. There are many causes that lead to bedsores, but the primary causes of why individuals (usually 50 years of age or older) contract bedsores are due to skin thickness weakening and becoming more brittle and thinner, lack of physical activity, lack of nutrition, a more pronounced increase in sensitivity, and a more delayed healing capability than younger individuals. It is estimated that there are approximately 3 million individuals in the United States who are experiencing pressure ulcers every year. In addition, the United States healthcare industry is spending around $9B to $11B annually for skin treatment.

What leads to a pressure ulcer? There are many variations such as spinal surgeries, brain surgeries, and major accidents that cause a broken leg or legs or becomes paralyzed. But the main reasons that lead to pressure ulcers include the following:

  1. Diabetes
  2. Hypertension
  3. Congestive Heart Failure (CHF)
  4. Chronic Obstruction Pulmonary Disease (COPD)
  5. Alzheimer’s Disease

Many of the factors that lead to health condition issues are due to a lack of frequent physical activity, proper nutrition, and clean water. In addition, cigarette smoking, extensive alcohol, and illegal drug use are other causes that lead to pressure ulcers.

It is reported that human beings have been exceeding their life expectancy compared to the last five decades. However, there will be a significant percentage of individuals in the United States who will face ailments and experience a tremendous lack of energy that will force them to spend most of their remaining lives resting in bed for an extended period.

There are four elements that contribute to pressure ulcer contraction, they are:

  1. Pressure
  2. Heat
  3. Moisture (Sweat)
  4. No Air Flow

SCENARIO: A patient rests stationary in bed in a supine position (Face upward) without movement for a very long time. A long time can be more than 4 hours.


Pressure is the continuous physical force or gravity exerted on or against an object by something in contact with another object. In this scenario mentioned above, gravity is pushing human body mass down on to the bed, forcing body weight on the mattress. The force is distributed throughout the human body, but the body parts that absorb the most pressure are the upper back, lower back (hip), head, and heels.

While the human body is resting in bed, force remains constant until the body is lifted off from the mattress. During that time when the body does not move, the pressure is already applying force on skin surfaces of the body and travels to the interior body under skin (Subcutaneous), muscle tissues, nerve tissues, capillaries (Branches of tiniest veins), and bones causing discomfort and pain to a patient. As the mattress is pushing force back to the body, and at the same time, gravity is pushing down to the human body, bones are absorbing weight and applying pressure onto muscle tissues, nerve tissues, veins and capillaries like a sandwich. Capillaries are the first to react and cannot tolerate force for so long. They will begin to suffocate (cutting of oxygen) and clot blood.


Heat is a temperature that is generated by kinetic energy (work) to produce from warmth to hotness. There are many types of heat (heat transformation, heat radiation, and heat transfer). The human body is always performing kinetic energy to keep a core temperature (Interior body) of range from 340 to 380 Celsius (93.1 to 100.40 Fahrenheit). The skin is an exterior surface body where the surface temperature is cooler than interior body. The normal skin temperature is ranged from 320 to 340 Celsius (89.60 to 93.20 Fahrenheit). The human heart acts like a motor and a regulator that controls pumping of blood flow, therefore, a heart performs kinetic energy and generates heat in a body. Muscles also perform work that radiates heat. When a certain muscle contracts, it pumps blood to move forward, circulate throughout a body, and returns to a heart. As we now know that a basic body generates heat, a certain surface area of back is heating especially when there is no space between a mattress and a surface back. When a body does not move for an extensive period, heat increases over time to high 500 Celsius (1220 Fahrenheit), heat is stimulated in a specific area of muscle tissues, nerve tissues, and capillaries. Heat is radiated and cannot cool down without convection or ventilation. Nerves send signals to brain, alerting it of discomfort or pain and retrieves it to the destination to deliver an effect; muscle tissues also feel irritations. This is where a redness of the skin surface begins to appear and a burning sensation causing discomfort and possibly pain.


Moisture is a liquid (in this case water), formed in a group of tiny drops located in air, substance, or surface. A human body contains water to keep organs, muscles, nerves, blood, and skin functioning to survive. The human body has sweat glands (sudoriferous) that differ between three types of glands; 1) Sebaceous glands that moisturizes skin also known as oily glands that contain a complex mixture of fats and waxes, 2) Eccrine glands are a skin temperature that acts like a regulator or better yet a thermostat that contains mostly water to maintain skin surface cool, and 3) Apocrine glands are the odor factor that contains a milky sweat that is in organic materials; when broken down by bacteria on the surface of the skin, it is the chief cause of body odor.

The sweat is a transparent, colorless, and acidic fluid with a peculiar odor. It contains some fatty acids and mineral matter. It is also called perspiration. In short, the function of a sweat gland is to keep skin cool.

Air Flow

Air is the invisible gaseous substance surrounding the Earth’s atmosphere, containing mainly a mixture of nitrogen and oxygen. The human body needs air to breathe as well as skin surface to survive. Air flow is the current in an atmosphere that circulates oxygen and nitrogen by a natural invisible force (wind) or by an artificial air flow such as air conditioner. The stronger the wind intensity, the cooler the air (depending on an environment). Not only is air flow vital for breathing, but also for cooling. Air flow cools most of the body’s surface to feel comfortable and dry.


When a patient rests in bed in a supine position without rotating for an extensive period, pressure is initially generated between the mattress and the back of the body. Heat is generated by the body’s natural temperature, and while there is no cavity for heat to escape, temperature rises to an elevated level that causes the back of the human body to sweat. During that stage, areas of sweating begin to soften skin tissue and eventually cause it to break open due to shear force. While broken skin tissues are opened, moisture falls into muscle tissues and a patient will feel a burning sensation.

If not detected on time, pressure, heat, and moisture can continue to dig deeper into the body’s dissolving tissues and all the way down to the bone. A huge hole is created causing a life threatening situation, and eventually a person’s life is terminated.

There are four stages of pressure ulcers that are defined by the National and International Pressure Ulcer Advisory Panels:

Stage 1/Category 1 Non-blanchable erythema

Intact skin with non-blanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area. The area may be painful, firm, soft, warmer or cooler as compared to adjacent tissue. Category I may be difficult to detect in individuals with dark skin tones. May indicate “at risk” persons.

Stage 2/Category 2 Partial thickness

Partial thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed, without slough. May also present as an intact or open/ruptured serum-filled or serosanginous filled blister. Presents as a shiny or dry shallow ulcer without slough or bruising*. This category should not be used to describe skin tears, tape burns, incontinence associated dermatitis, maceration or excoriation. *Bruising indicates deep tissue injury.

Stage 3/Category 3 Full thickness skin loss

Full thickness tissue loss. Subcutaneous fat may be visible, but bone, tendon or muscles are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling. The depth of a Category/Stage III pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput and malleolus do not have (adipose) subcutaneous tissue and Category/Stage III ulcers can be shallow. In contrast, areas of significant adiposity can develop extremely deep Category/Stage III pressure ulcers. Bone/tendon is not visible or directly palpable.

Stage 4/Category 4 Full thickness tissue loss

Full thickness tissue loss with exposed bone, tendon or muscle. Slough or eschar may be present. Often includes undermining and tunneling. The depth of a Category/Stage IV pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput and malleolus do not have (adipose) subcutaneous tissue and these ulcers can be shallow. Category/Stage IV ulcers can extend into muscle and/or supporting structures (e.g., fascia, tendon or joint capsule) making osteomyelitis or osteitis likely to occur. Exposed bone/muscle is visible or directly palpable.

There is virtually a fifth stage that only applies in the United States:

Stage 5 Unstageable/Unclassified: Full thickness skin or tissue loss – depth unknown

Full thickness tissue loss in which actual depth of the ulcer is completely obscured by slough (yellow, tan, gray, green or brown) and/or eschar (tan, brown or black) in the wound bed. Until enough slough and/or eschar are removed to expose the base of the wound, the true depth cannot be determined; but it will be either a Category/Stage III or IV. Stable (dry, adherent, intact without erythema or fluctuance) eschar on the heels serves as “the body’s natural (biological) cover” and should not be removed.

Suspected Deep Tissue Injury – depth unknown

Purple or maroon localized area of discolored intact skin or blood-filled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, firm, mushy, boggy, warmer or cooler as compared to adjacent tissue. Deep tissue injury may be difficult to detect in individuals with dark skin tones. Evolution may include a thin blister over a dark wound bed. The wound may further evolve and become covered by thin eschar. Evolution may be rapid exposing additional layers of tissue even with optimal treatment.

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