Prevention of Acquired Pressure Related Injuries

INTRODUCTION

Acquired pressure injuries have become an area of particular importance in the perioperative environment in recent years. Injuries result in discomfort and disability for the patient, and add to the costs of providing health care. The Australian experience places pressure injury adding close to $350 million per year to health care costs (Lewis, Pearson & Ward, 2003, p92).

This essay will examine a sample of the current literature available surrounding the issue. It will compare and contrast the results of studies. The quality of the information available will also be scrutinised with regard to the consensus of opinion. This will be done within the context of using available data to establish and maintain patient safety within the perioperative setting.

Acquired pressure related injuries can be broken into several categories, which will be mentioned briefly, however, the main emphasis of this essay will be in relation to pressure ulcers in particular as this is the most commonly identified form of injury.

ACQUIRED PRESSURE RELATED INJURIES

Application of pressure to a body part may result in an injury which is of a temporary or permanent nature. Normal function and appearance may return spontaneously once the pressure is released. If not, the resultant damage may cause a disability which can last from weeks to months or become permanent (Heizenroth, 2003).

Injuries which are most commonly defined as being caused by pressure are pressure ulcers (also called pressure sores) and nerve damage. Compartment syndrome in the lower limb, related to lithotomy positioning, is identified as another outcome from the application of pressure during the perioperative experience (Mumtaz, Chew & Gelister, 2002). McEwen (1996) and Heizenroth (2003) concurred with Mumtaz et al (2002), but went further to add alopecia as another possible adverse outcome.

PRESSURE ULCER FORMATION

The compression of soft tissue between a bony prominence and an external surface for a prolonged period of time may lead to the formation of a pressure ulcer. Tissue damage may extend through the epidermis, dermis, subcutaneous fat, muscle and bone. Damage may be a result of occluded blood flow causing tissue ischaemia, and reperfusion injury which contributes to cell destruction and tissue death. Toxic intracellular material may also be present due to the rupture of cell membranes, and the inability of the lymph system to remove toxins because of lymph vessel damage. This contributes to tissue necrosis (Australian Wound Management Association (AWMA), 2001).

CONCEPTUAL MODEL

Braden and Bergstrom (as cited in Defloor, 1999) created a conceptual model in an attempt to detect the risk of pressure ulcer development. They identified the causal factors for pressure ulcer development as pressure and tissue tolerance. These two causative factors were subdivided further. Tissue tolerance was identified as having intrinsic and extrinsic factors.

Consensus among the literature reviewed for this essay suggests that this model has become the widely accepted theory to explain the development of pressure ulcers. Defloor (1999) modified this model in an attempt to develop a model which explained the perioperative development of pressure ulcers.

THE PERIOPERATIVE EXPERIENCE

The operating room environment presents a unique situation for our patients. They are exposed to many potential hazards which increase their chance of acquired pressure injuries; pressure ulcers in particular (Schouchoff, 2002). Pre-operative assessment to identify patients who are particularly at risk and recognition of risks which are peculiar to the perioperative environment is essential in order to plan and establish a safe environment for the patient's surgical experience.

TISSUE TOLERANCE

Tissue tolerance, the body's ability to withstand sustained pressure, is regarded as the factor which determines whether a pressure ulcer will form (Defloor, 1999). Both intrinsic and extrinsic factors determine tissue tolerance.

Intrinsic factors

Aronovitch (2002) identifies intrinsic risk factors as age, body size, nutritional status, and diabetes or hypertension. Pre-operative assessment should include assessment of these risks and an evaluation of skin integrity (McEwen, 1996; Armstrong & Bortz, 2001). This evaluation should be noted in the patient's record as a means for comparison during the post-operative period. While the pre-operative assessment will provide indicators for patients at risk, it is not possible to change any of these intrinsic risk factors.

Age

Age has been identified as the most statistically significant intrinsic risk factor in many studies (Armstrong & Bortz, 2001, p652). An explanation offered by Defloor (1999, p211) is the loss of the ability of the tissue to effectively distribute pressure due to a lack of elastin. Changes in collagen synthesis also result in decreased mechanical potential of the tissue whereby it becomes stiffer and less pressure-resistant.

Body size

Research reveals differing views on body size as a risk factor. Aronovitch (2002) claims obese patients put more weight and pressure on their bony prominences and so are particularly at risk. Defloor (1999) regards patients who are thin or underweight as generally at higher risk of pressure ulcer development as they lack the subcutaneous tissue to redistribute pressure over bony prominences. Whilst he agrees with Aronovitch in general regarding the obese patient, he goes on to deduce that these pressures are distributed across a wider area, and so are not as likely to cause problems as in the thinner person. Gallagher (2002, p72) identifies the obese patient as being at risk of atypical ulcers formation. These can occur due to pressure from overlapping layers of skin folds. They are also at risk of pressure ulcer development from tubes and catheters which may burrow into skin folds and erode the surfaces.

Extrinsic factors

Extrinsic factors alone will not cause pressure ulcer formation. However, their presence will lessen the body's tolerance for pressure (Armstrong & Bortz, 2001). These factors include temperature, shearing, friction, and moisture (Schouchoff, 2002). It is possible to limit the impact of these factors within the perioperative environment.

Temperature

During surgery the body is exposed to anaesthetic agents that reduce its ability to regulate temperature. Exposure of