Pressure-Induced Skin and Soft Tissue Injury
Bedsores, also called “decubitus” ulcers and pressure ulcers, result from compression of soft tissue between an external surface (furniture or bedding) and a bony prominence, long enough to result in tissue damage. They are the most common complications in hospitalized and long-term institutionalized care.
Causes of Bedsores
When pressure applied to skin is greater than the arterial pressure that vascularizes that skin (32 mmHg), blood flow ceases. Not only tissue hypoxia develops, but also the accumulation of metabolic waste products which can be toxic. Prolonged (2 hours) or higher pressures (70 mmHg) can cause irreversible tissue damage.
Pressures are greatest over bony prominences:
● Lying on a mattress: 150 mmHg.
● Sitting: up to 300 mmHg over the ischial tuberosities.
Tissue Casualties of Bedsores
Muscle is the most susceptible to tissue damage. In decreasing order, the susceptibility to tissue damage is as follows:
- Subcutaneous fat
This susceptibility scale explains how a deeper injury (i.e., muscle) can have severe damage with no evidence seen on the overlying skin, only to have that injury progress to the surface later. The extent of the initial injury is always greater than what may be seen in a visible bedsore on the skin.
- Sensory loss
- Peripheral vascular disease and decreased perfusion, especially due to venous stasis