Bedsore

Bedsores, more properly termed pressure ulcers, are ulcers (sores) caused by pressure, friction or shear on vulnerable areas of the body, such as bony or cartilaginous areas. Vulnerability to the effects of pressure, friction and shear are exaggerated by moisture, immobility and general debility. Decubitus ulcers are pressure ulcers that occur when the patient lies on his or her back for long periods (Wilhelmi and Neumeister, 2005). Examples of areas vulnerable to pressure ulcers include the hips, ankles, heels, elbows, ears, and pressure points on the lower back (near the tail bone, sacrum, or iliac crest). Pressure sores are also caused by prolonged sitting, or certain patterns of sitting behaviour (Bain and Ferguson-Pell, 2002). Devices such as braces can also cause pressure ulcers.

Classification

The definitions of the four pressure ulcer stages are revised periodically by the National Pressure Ulcer Advisory Panel //www.npuap.org/(NPUAP) in the United States. Briefly, however, they are as follows:

Stage I is the most superficial, indicated by redness that does not subside after pressure is relieved. The epidermis remains intact.
Stage II is damage to the epidermis extending into, but no deeper than, the dermis.
Stage III involves the full thickness of the skin, extending into, but not through, the subcutaneous tissue layer. This layer has a relatively poor blood supply and can be difficult to heal.
Stage IV is the deepest, extending into the muscle, tendon or even bone.
Unstageable pressure ulcers are covered with dead cells and wound exudate, so the depth cannot be determined.

With higher stages, healing time is prolonged. While about 75% of stage 2 ulcers heal within 8 weeks, only 62% of stage 4 pressure ulcers ever heal, and only 52% heal within one year (Thomas et al., 2005). It is important to note that pressure ulcers do not regress in stage as they heal. A pressure ulcer that is becoming shallower with healing is described in terms of its original deepest depth, e.g., "healing Stage II pressure ulcer."

Pathophysiology

Pressure ulcers may be caused by inadequate blood supply and resulting reperfusion injury when blood re-enters tissue. A simple example of a mild pressure sore may be experienced by healthy individuals while sitting in the same position for extended periods of time: the dull ache experienced is indicative of impeded blood flow to affected areas. Within hours, this shortage of blood supply, called ischemia, may lead to tissue damage and cell death. The sore will initially start as a red, painful area, which eventually turns purple. Left untreated, the skin may break open and become infected. Moist skin is more sensitive to tissue ischemia and necrosis, and is also more likely to get infected. Shear is a separate mechanism of tissue damage that results in ripping of deeper tissue layers, and it may not immediately cause a visible change in skin condition. Shear injury may manifest as bruising or changes in tissue temperature and color and, later, tissue sloughing and necrosis. Unlike friction, shear injury may cause deep tissue damage.

Epidemiology

Some studies suggest that 3 to 10 percent of hospitalized patients have pressure sores, with two-thirds occurring to patients over the age of 70. Younger people with neurological impairments also develop pressure sores, because they remain in one position and cannot feel irritation or building pressure. Between five and eight percent of these people have pressure sores during a year.

Prevention

The condition is prevalent in sedentary individuals, such as those living with paralysis or confined to a bed because of illness or impairment.

Nursing homes and hospitals usually set programs to avoid the development of bedsores in bedridden patients (e.g. moving them every two hours, using a standing frame to reduce pressure, ensuring dry sheets, etc.). Poor nutrition is also a major factor in the formation of pressure sores.

Pressure-distributive mattresses are used to reduce high values of pressure on prominent or bony areas of the body. However, methods to evaluate the efficacy of these products have only been developed in recent years (Bain et al 1999).

Complications

Pressure sores can trigger other ailments, and cause patients considerable suffering and financial cost (Brem et al., 2004). Some complications include autonomic dysreflexia, bladder distension, osteomyelitis, pyarthroses, sepsis, amyloidosis, anemia, urethral fistula, and very rarely malignant transformation. Sores often recur because patients do not follow recommended treatment or develop seromas, hematomas, infections, or dehiscence. Paralytic patients are the most likely people to have pressure sores recur.

In some cases, complications from pressure sores can be life-threatening. The most common causes of fatality stem from renal failure and amyloidosis.

References

Bain DS, Ferguson-Pell MW. Remote monitoring of sitting behaviour of people with spinal injury. Journal of Rehabilitation Research and Development, Vol 39, 4, July 2002, Pages 513-520.
Brem H, Kirsner RS, and Falanga V. Protocol for the successful treatment of venous ulcers. The American Journal of Surgery, Volume 188, Issue 1, Supplement 1, July 2004, Pages 1-8.
Thomas DR, Marilyn R. Diebold and Linda M. Eggemeyer. A controlled, randomized, comparative study of a radiant heat bandage on the healing of stage 3–4 pressure ulcers: A pilot study. Journal of the American Medical Directors Association, Volume 6, Issue 1, January-February 2005, Pages 46-49.
Bain DS, Nicholson N, Scales JT. A phantom for the Assessment of Patient Support Systems. Med Eng & Phys. 21 (1999), 293–301.
Wilhelmi BJ and Neumeister M. 2005. Pressure Ulcers: Surgical Treatment and Principles. Emedicine.com. Available.

External links

Bed Sores and Pressure Ulcers
eMedicine.com article: "Pressure Ulcers, Surgical Treatment and Principles"
Bed Sores and Pressure Ulcers
Maggot Therapy Project web site at the University of California, Irvine, list of maggot therapy practitioners
http://www.monarchlabs.com/ suppliers of Medical Maggots™ (disinfected Phaenicia sericata larvae), picture of Medical Maggots™ vial
BioTherapeutics Education and Research Foundation

Dermatology