Pressure Lessons

By Ann Gutierrez, MSN, RN, CRRN-A

Ann Gutierrez, MSN, RN, CRRN-A

It is a well-known fact that immobility, pressure, poor nutrition, incontinence, lowered mental alertness, and lack of sensation lead to pressure ulcers. Still, the European Pressure Ulcer Advisory Panel (EPUAP) says 95% of these ulcers are preventable.¹ So, if a myriad of specialty beds and mattresses that help prevent skin breakdown are available, how do we choose among them to start this prevention?

Pressure ulcers are lesions caused by unrelieved pressure resulting in damage of underlying tissue.² They usually occur when soft tissue is compressed between an external surface and a boney prominence for a prolonged period. This external pressure is higher than capillary blood flow pressure, which results in cellular ischemia. Prolonged ischemia leads to death of the cells and tissue.³

Another force that contributes to breakdown is shear pressure, a horizontal force that occurs when the skin and the underlying tissue are overstretched, causing deformity, obstruction of blood flow, and tissue necrosis.⁴ Pressure ulcers occur most frequently in patients who are immobilized, debilitated, and elderly. The estimation of prevalence of pressure ulcers in the United States is between 1.5 million and 3 million. Approximately 5% of patients admitted to acute care hospitals develop a pressure ulcer.⁵

RISK ASSESSMENT

Identification of patients at risk for pressure ulcers and initiation of measures to prevent them help decrease their incidence. This will bring us one step closer to meeting the Healthy People 2010 lists of initiatives for health care providers.⁶

The National Pressure Ulcer Advisory Panel (NPUAP) recommends that a pressure ulcer risk assessment be performed on a patient’s admission to a health care facility, and patients should be reassessed as their condition changes. The risk assessment should evaluate the factors that are commonly associated with pressure ulcer development.³ The Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare Research and Quality) recommended the Braden Scale and the Norton Scale as being appropriate for assessing a patient’s risk for pressure ulcers.² The objective of these scales is primarily to predict occurrence. Since the scores are determined by direct observation by a nurse, they can be used to individualize the interventions needed for patients who already have pressure ulcers, and those who are at risk. Once the score is determined, it is then important to select the appropriate interventions.

Pressure ulcers are staged using the guidelines proposed by the NPUAP and the AHCPR. Staging determines the degree of damage that has occurred to the tissue, and is used as a tool for both communication and assessment (see Table 1).

Table 1. Pressure ulcer staging guidelines as proposed by NPUAP (Stage 1)7 and ACHPR (Stages II-IV).²

Interventions to reduce pressure over boney prominences and the establishment of turning schedules for bed-ridden patients at risk for pressure ulcers are of utmost importance. The exact amount of time that a patient should remain in one position has not been fully researched. However, the AHCPR guidelines recommend that if the patient is at risk for pressure ulcers, he or she should be repositioned every 2 hours if consistent with the patient’s overall goals. The frequency of repositioning should be determined by the results of skin inspection, not by a ritualistic schedule. The panel also recommends a written schedule for systematically turning and repositioning the patient.² When determining the amount of time a patient should remain in one position, it is important to begin with 2-hour intervals and assess the patient’s skin after each repositioning. If the plan is to increase the time a patient stays in one position, then the intervals should be increased by 30 minutes for several days, and the skin should be reassessed each time the patient is repositioned.

CHOOSING SUPPORT SURFACES

The AHCPR guidelines cite evidence that pressure-reducing devices can and do decrease the incidence of pressure ulcers. They also state there is no evidence to prove that one support surface consistently performs better than others.²

Gutierrez adjusts a mattress to ensure the lowest risk for pressure ulcers.

Opening the Pandora’s box of specialized mattresses and beds that prevent or treat pressure ulcers can be intimidating. Therefore, several factors should be considered when selecting a support surface. These include: clinical condition of the patient, characteristics of the care setting, characteristics of the support surface needed, ease of care, requirements for maintenance, cost, and patient preference.⁸

Once a risk assessment has been completed, the nurse determines if the patient is in a low, moderate, or high risk category for developing skin breakdown. If a patient is in a low risk category, a standard mattress can usually be used without the need for a special support surface. However, it is imperative that nursing interventions be implemented.

If the patient’s risk status is moderate to high or if the patient already has pressure ulcer(s), the nurse must determine appropriate preventive interventions to address repositioning needs and reduction of pressure by using an overlay mattress, replacement mattress, or a specialty bed. It is a known fact that wounds created by pressure will not heal unless the pressure is reduced.⁷

Support surfaces can be divided into two categories: pressure-reducing and pressure-relieving.

PRESSURE-REDUCING SURFACES

Pressure-reducing support surfaces can be either static or dynamic. Static surfaces reduce pressure by spreading the pressure over a large area. They lower the tissue interface pressure, but do not consistently maintain this pressure below capillary closing pressure (12-32 mm Hg) in all positions. They do not require electricity and usually lay on top of a standard hospital mattress. Some examples of static support surfaces are foam, air, or gel mattresses/overlays and water mattresses.⁹

Foam overlays can be flat with a contour or have geometric cuts. The density should be at least 1.3 pounds per square foot and 3-4 inches thick.⁹ These overlays are recommended for patients with a low risk for pressure ulcers. The advantages are a one-time charge, low cost, and easy use. Disadvantages are they retain moisture and heat, and do not reduce shear; the patient may bottom out; and cleaning and disposal are problems.¹⁰

Water- and gel-filled overlays are plastic or vinyl bags filled with either water or a gel substance. They are recommended for low pressure ulcer risk and for Stage I pressure ulcers.⁹ Their advantages are low cost, easy use, and reduction of shear. Disadvantages are they retain moisture and heat, the patient may bottom out at boney prominences, they may leak if punctured, transfers are difficult, and they may be heavy and difficult to move.¹⁰ Air-filled pressure pads/mattresses have interlocking air cells. They are recommended for patients at low risk for skin breakdown or with Stage I and II pressure ulcers.⁸ Their advantages are they are durable and easy to clean, they have a one-time charge, and some models have pull tab check valves that deflate rapidly.

Disadvantages are they retain moisture and heat, sharp objects may puncture them, and some models may require maintenance.¹⁰

A big concern when using mattress overlays is bottoming out. It occurs when the patient’s body sinks into the mattress and there is no protection to the boney prominence of concern. This is tested by inserting a flat outstretched hand between the patient’s boney prominence and the overlay. If there is less than one inch between the mattress/overlay and the patient, the patient has bottomed out.⁸

Dynamic support surfaces move. They require a motor or a pump and electricity to operate. Most dynamic support surfaces have an electric pump that alternately inflates and deflates air cells. The amount of time the pump takes to complete a cycle of inflation and deflation determines effectiveness.⁹ These support surfaces are recommended for patients with low to moderate risk for pressure ulcers and with Stage II pressure ulcers on multiple turning surfaces. Their advantages are they are durable and easy to clean. Disadvantages are problems with moisture and heat retention, high cost if rented, and required setup, monitoring, and electricity.¹⁰

A low air-loss overlay is also a type of dynamic support surface. It is also recommended for patients with low to moderate risk for skin breakdown and for those who have a Stage I or II pressure ulcer. These mattresses have multiple air cushions calibrated to each patient’s needs. Advantages are they provide pressure reduction over the entire body surface, the mattress cover minimizes shear and moisture, and some models have battery power backup. Disadvantages are they require mechanical setup and monitoring, caregiver training, and electricity.¹⁰

A dynamic flotation mattress cycles air with a built-in pump. It is recommended for patients with moderate to high risk for ulcers and with Stage II, III, and IV pressure ulcers. Advantages are the cover reduces shear and friction, it is self-monitoring, and some models have a quick disconnect for CPR. Disadvantages are they require mechanical setup and electricity.¹⁰

PRESSURE-RELIEVING SURFACES

Pressure-relieving support surfaces consistently reduce the interface pressure below the capillary closing pressure (12-32 mm Hg). This is accomplished in any position and most body locations. The three types of pressure-relieving support surfaces are: low-air-loss therapy, air fluidized or high-air-loss therapy, and kinetic or lateral rotation therapy.⁹

Low-air-loss therapy consists of a modified bed frame with multiple connected air cushions calibrated to the needs of the patient. It is covered with a fabric that provides low friction and shear reduction. Low-air-loss therapy is recommended for treatment of Stage II, III, and IV pressure ulcers.⁹ The advantages are maximum pressure reduction over the entire body, and reduced heat and moisture; some models have a CPR quick release lever. Disadvantages are a trained person is needed to adjust settings for setup; mechanical setup, monitoring, and electricity are required; there is no backup power system; caregiver training is increased; and the cost is high.¹⁰ Also, this bed may generate heat, therefore the dressing may dry out, and it may need additional cooling efforts, as well as monitoring of intake and output to prevent dehydration.⁹

Air-fluidized or high-air-loss therapy is provided by a bed frame that contains silicone-coated glass beads. When air is pumped through the bed, the beads become fluidized and act like a liquid. It has bactericidal properties as a result of the beads’ alkalinity (pH=10), entrapment of organisms by the beads, and the bed’s temperature. The drying effect of the bed reduces moisture, and because most insurers will not reimburse for this reason, these beds are not used for prevention of skin breakdown. The beds are reserved for patients with severe skin problems that have not responded with the use of other beds/mattresses.⁹ Advantages are less frequent positioning is required, they relieve moisture and shear, and they have a firm setting for CPR. Disadvantages are activities of daily living and transfers are more difficult; they need mechanical setup, monitoring, and electricity; there is no backup power system; and high cost.¹⁰ If not turned frequently, patients may develop pneumonia; so they are contraindicated for patients with coexisting pulmonary disorders.

The third type of pressure-relieving therapy is kinetic or lateral rotation, which is used to counter the effects of immobility by its continuous passive motion (CPM). When manual repositioning is difficult or patients are confined to a bed, kinetic therapy is thought to improve respiratory function and oxygenation, prevent renal stasis, and increase venous flow. Laterally repositioning the patient also allows the skin to recover from pressure, especially in beds that also have low-air-loss therapy, which prevents skin breakdown. Preliminary results from the Cleveland Clinic demonstrate a preliminary improvement in pressure ulcer healing using the combined beds.¹¹

CONCLUSION

Support surfaces are an important part of any plan for prevention or treatment of pressure ulcers. There is a wide array of support surfaces to choose from such as overlays, replacement mattresses, and specialty beds. However, this variety, as well as the lack of consistent information available, can make a decision complicated. Therefore, the NPUAP is involved in a 3-year initiative to develop standardized guidelines for testing in the United States, and will work with the EPUAP to develop international standards.¹²

Ann Gutierrez, MSN, RN, CRRN-A, is program educator for Spinal Cord Injury and Specialty Rehab Programs at The Institute for Rehabilitation and Research, Houston.

REFERENCES

Maylor M, Torrance C. Nursing attitudes, beliefs and knowledge in relation to pressure sore prevention. European Pressure Ulcer Advisory Panel. Available at: www.epuap.org. Accessed October 29, 2002.

Bergstrom N, Bennett MA, Carlson CE, et al. Clinical Practice Guideline No. 3: Pressure Ulcers in Adults: Prediction and Prevention. Rockville, Md: US Dept of Health and Human Services, Agency for Health Care Policy and Research; 1992. AHCPR Publication 92-0047.

National Pressure Ulcer Advisory Panel. Statement on pressure ulcer prevention: 1992. Available at: www.npuap.org Accessed October 9, 2002.

Department of Internal Medicine, Geriatric Medicine, Mayo Clinic. Pressure Ulcers: Prevention and Management, 2001. Mayo Foundation for Medical Education and Research. Available at: www.mayo.edu Accessed October 10, 2002

Wound Care Information Network. Introduction-Cause of pressure ulcers. Available at: www.medicaledu.com Accessed October 9, 2002.

Healthy People 2010. US Department of Health and Human Services. Available at: www.health.gov Accessed October 29, 2002.

National Pressure Ulcer Advisory Panel. NPUAP statement on reverse staging of pressure ulcers. Available at: www.npuap.org Accessed October 28, 2002.

Clinical Practice Guidelines. Pressure Ulcer Prevention and Treatment Following Spinal Cord Injury: A Clinical Practice Guideline for Health-Care Professionals. Washington, DC: Consortium for Spinal Cord Medicine; 2000. Paralyzed Veterans of America.

Bates-Jensen BM. Pressure ulcers: pathophysiology and prevention. In: Sussman C, Bates-Jensen BM, eds. Wound Care: A Collaborative Practice Manual for Physical Therapists and Nurses. Gaithersburg, Md: Aspen Publishers Inc; 1998:255-260.

Carroll P. Bed selection: help patients rest easier. RN. 1995;58(5):44-51.

Reger SI, Browning G, Sahgal V. Evaluation and clinical trials of Low-Air-Loss Support Systems with and without lateral body rotation. Available at: www.clevelandclinic.org/rehab. Accessed October 9, 2002.

National Pressure Ulcer Advisory Panel. National Pressure Ulcer Advisory Panel’s support surface standards initiative (S31). Available at: www.npuap.org Accessed October 4, 2002.