Aveneu Park, Starling, Australia

Intrinsic Force is generated by patient movement through gravity

Intrinsic factors:

·         Nutritional intake: Poor nutrition plays a major role in pressure ulcers formation. Insufficiencies can be either from decreased intake or poor absorption. Malnutrition, low levels of protein and albumin, recent weight loss or morbid obesity all increase the risk of pressure ulcer formation. Lack of Vitamin C and zinc may also increase the risk.

·         Demographics: Characteristic that may increase pressure ulcers are being over the age of 65, Males are at higher risk, being of colour and also co-morbidities. also if there is previous history of pressure sore injury, including reperfusion injury and those extending beyond the level of the dermis. 

·         Oxygen delivery system : Lack supply of oxygen leads to increase risk. Risk conditions such as respiratory disorders, cardiovascular impairment and smoking

·         Chronic illness: some chronic illness such as diabetes, metastatic cancer and renal failure may lead to a higher risk.

·         Pain levels: If there are high pain levels they can limit the patient’s movement

·         Medications: Drugs can have a variety of effects including; decreased sensation, drowsiness leading to decreased movement, decreased inflammatory response, decreased peripheral blood pressure.

Extrinsic Factors:

·         Shearing : Shearing forces are exerted parallel to the skin and are generated by forces acting in opposite directions. Force is generated by patient movement through gravity and sliding or by incorrect manual handling

·         Friction : Friction is resistance to movement between the patient’s skin and the external support surface. This force acts in a direction that is opposite to patient movement. Abrasions of the epidermis and dermis occur as a result of friction between the skin and the bed surface. Tissues, which are attached to the bone, are compressed, obstructed and torn in both shear and friction situations.

·         Shearing and friction occur; when the patient slides in bed or chair, when the patient’s, when the patient is pulled across bed or chair as a result of incorrect manual handling, causing friction between the skin and bed or chair’s surface, it occurs also when the patient is restless or has limb spasms, leading to friction between the skin and the bed surface

·         Moisture: Moisture changes the resistance of the skin to external forces by softening the surface of the skin and decreasing the muscle strength. Urine, faeces, perspiration or wound drainage may soften the skin, making the skin more predisposed to pressure, shear and friction.