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How and Why to Do Pressure Ulcer Risk Assessment

Ayello, Elizabeth A. PhD, RN, CS, CWOCN; Braden, Barbara PhD, RN, FAAN

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Pressure ulcers (PUs) are a common problem across all health care settings. In a recently published monograph, “Pressure Ulcers in America: Prevalence, Incidence, and Implications for the Future,”1 the National Pressure Ulcer Advisory Panel (NPUAP) estimates that PU prevalence in acute care is 15%, with incidence of 7%. Although methodological issues require caution in interpreting the data, the estimates are based on several large studies conducted from 1990 to 2000 (Table 1). The data represent the percentage of patients with PUs among those surveyed in a setting (prevalence) and the percentage of patients who developed PUs after admission to the setting (incidence).

Table 1
Table 1:

Identifying individuals at risk for PUs and initiating preventive measures is an important means of reducing PU prevalence and incidence. This concept has taken on even greater urgency now that the Healthy People 2010 initiative lists reducing PU incidence as an objective for health care providers. 2

In addition, the Centers for Medicare and Medicaid Services (CMS, formerly the Health Care Financing Administration) now considers a PU to be a sentinel event in a resident of a long-term-care facility who had been assessed as being at low risk for a PU. According to CMS, the only residents who are at high risk are those who have impaired transfer or bed mobility, are comatose, malnourished, or have end-stage disease; any other patient is at low risk.


The clinical practice guideline on PU prevention from the Agency for Health Care Policy and Research (AHCPR; now the Agency for Healthcare Research and Quality [AHRQ]) 3 provides a starting point for identifying at-risk individuals who need preventive interventions and the specific factors that place these individuals at risk.

For example, bedfast and chairfast individuals or those with impaired ability to change position are at risk for PUs because of immobility. The guideline suggests that these individuals be assessed for additional factors that increase risk for developing PUs, including incontinence, nutritional factors such as inadequate dietary intake or impaired nutritional status, and altered level of consciousness. 3 All risk assessments should be documented, according to the guideline. 3 This may be accomplished by using a validated risk assessment tool.

Several PU risk assessment tools are available to help practitioners identify individuals who might develop a PU. These include the Norton Scale, 4 the Gosnell Scale, 5 the Braden Scale, 6 the Knoll Scale, 7 and the Waterlow Scale. 8 The Norton and Waterlow Scales are from Europe; the Gosnell, Braden, and Knoll Scales were created in the United States.

Which scale should be used? Clinicians should decide by examining the reliability (consistency) and validity (accuracy) of the scales. Reliability for this type of clinical tool is usually described by interrater reliability. A common measure of interrater reliability for a risk assessment tool is percentage agreement, which looks at the percentage of instances in which different raters assign the same score to the same patients. Validity, or accuracy, is measured by the ability of the tool to correctly predict who will or will not develop a PU.

Predictive validity is expressed as sensitivity and specificity of the tool. Sensitivity is the percentage of individuals who develop a PU who were assessed as being at risk for a PU. A tool has good sensitivity if it correctly identifies true positives while minimizing false negatives. Specificity is the percentage of individuals who do not develop a PU who were assessed as being not at risk for developing an ulcer. A tool has good specificity if it identifies true negatives and minimizes false positives.

Two risk assessment scales—the Norton and the Braden Scales—are mentioned in the AHCPR guideline as being appropriate clinical tools for determining PU risk because of the amount of clinical research supporting their reliability and validity. 3 The remainder of this discussion focuses on the Braden Scale, the most commonly used PU assessment scale in the United States.


Translated into many languages and used on every continent, the Braden Scale was created by Barbara Braden, PhD, RN, FAAN, and Nancy Bergstrom, PhD, RN, FAAN, in 1987. 6 The Braden Scale has 6 subscales: sensory perception, moisture, activity, mobility, nutrition, and friction/shear (see Braden Scale). These categories address the 2 primary etiologic factors of PU development: intensity and duration of pressure and tissue tolerance for pressure. Sensory perception, mobility, and activity address clinical situations that predispose a patient to intense and prolonged pressure, while moisture, nutrition, and friction/shear address clinical situations that alter tissue tolerance for pressure.

Each of the subscales is ranked with a numerical score. Five of the subscales—sensory perception, mobility, activity, moisture, and nutrition—have scores that range from 1 to 4, with 1 representing the lowest score and 4 representing the highest. Friction/shear has a score that ranges from 1 to 3. Descriptions of the terms for ranking are provided on the scale. Each of the 6 subscale scores are then totaled to give a final Braden Scale score. Scores can range from 6 to 23.

As Braden Scale scores become lower, predicted risk becomes higher. Braden and Bergstrom have identified incremental changes in risk, based on the percentage of patients who can be expected to develop PUs at those scores: 15 to 18, at risk; 13 to 14, moderate risk; 10 to 12, high risk; and 9 or below, very high risk. These levels of risk may also be helpful in determining how aggressive preventive efforts should be and in evaluating the success of these efforts.

Clinical judgment, however, is always necessary to interpret the risk. For example, a patient is likely to have a very low score immediately following surgery because he or she would be profoundly immobile and would have a diminished level of consciousness. However, a young patient who is expected to be ambulatory within a few hours is not likely to require intervention to avoid a PU.

In other instances, a patient may exhibit risk factors that are not measured by the Braden Scale. Researchers have identified advanced age (older than age 80), low diastolic blood pressure (less than 60), increased body temperature, and poor current dietary intake of protein as important predictors of PU risk. 9 Other risks that should be taken into account are peripheral vascular disease, prolonged surgery (particularly involving extracorporeal oxygenation), or intractable pain.

Calculating the Braden Scale Score demonstrates how to score the subscales of the Braden Scale and determine a total risk assessment score.


The AHCPR clinical practice guideline on pressure ulcer prevention 3 recommends that initial PU risk assessment be done on admission and that reassessments be done at periodic intervals. The guideline is not specific as to how often the reassessments should be done, however.

The question of when to assess a patient for PU risk has 2 facets: (1) how often to assess and reassess a patient for PU risk, and (2) what time of day is best to perform the assessment. 9,10 Reassessment intervals essentially need to be based on the acuity of the individual for whom the PU risk is being assessed, when most PUs occur in that particular clinical setting, and how rapidly a patient’s condition is changing (either improving or declining). Research by Bergstrom and Braden found that in a skilled nursing facility, 80% of PUs developed within 2 weeks of admission and 96% developed within 3 weeks of admission. This evidence was the basis for the following recommendations on assessment and reassessment. 9,10

  • Acute care— initial assessment on admission, then reassessment at least every 48 hours or whenever the patient’s condition changes.
  • Long-term care— initial assessment on admission, then reassessment weekly for the first 4 weeks, monthly to quarterly after that, and whenever the resident’s condition changes.
  • Home health care— on admission initially, then reassessment with every visit.

Regarding the time of day that is best for assessment, Bergstrom and Braden studied whether scores obtained by risk assessment varied by time of day and found no differences. Outside of home care, patient care activities can vary from shift to shift. Risk assessment may be scheduled on either the day or evening shift, depending on when it will best fit with work patterns and be performed most consistently.


After the Braden Scale score is tallied, the next step is to link the risk assessment to preventive protocols. Because each health care agency may differ in terms of staffing patterns, access to clinicians who specialize in wound care, and the preventive products utilized, it is difficult to prescribe a set of protocols that will fit all circumstances; however, a broad outline of protocol development has been developed. More specific protocols should be written by each agency and staff education for use of these protocols must be provided prior to their implementation.

  • At risk: 15 to 18— Consider a protocol of frequent turning; facilitating maximal remobilization; protecting the patient’s heels; providing a pressure-reducing support surface if the patient is bedfast or chairfast; and managing moisture, nutrition, and friction and shear. If other major risk factors are present (advanced age, fever, poor dietary intake of protein, a diastolic blood pressure below 60 mm Hg, hemodynamic instability), advance to next level of risk.
  • Moderate risk: 13 to 14— Consider a protocol of frequent turning; facilitating maximal remobilization; protecting the patient’s heels; providing a pressure-reducing support surface; providing foam wedges for 30-degree lateral positioning; and managing moisture, nutrition, and friction and shear. If other major risk factors are present, advance to the next level of risk.
  • High risk: 10 to 12— Consider a protocol that increases the frequency of turning; supplements turning with small shifts in position; facilitates maximal remobilization; protects the patient’s heels; provides a pressure-reducing support surface; provides foam wedges for 30-degree lateral positioning; and manages moisture, nutrition, and friction and shear.
  • Very high risk: 9 or below— Consider a protocol that incorporates the points for high-risk patients plus uses a pressure-relieving surface if the patient has intractable pain, severe pain exacerbated by turning, or additional risk factors such as immobility and malnutrition. A low-air-loss bed is no substitute for a turning schedule.

More interventions

The following suggestions can help manage a patient’s moisture, nutrition, and friction and shear:

  • Managing moisture— Use a commercial moisture barrier, and use absorbent pads or diapers that wick and hold moisture. Address the cause of moisture if possible, and offer a bedpan or urinal and a glass of water in conjunction with turning schedules.
  • Managing nutrition— Consult a dietitian and act quickly to alleviate nutritional deficits. Increase the patient’s protein intake and increase his or her calorie intake if needed. Supplement with a multivitamin containing vitamins A, C, and E.
  • Managing friction and shear— Elevate the head of the bed no more than 30 degrees, and have the patient use a trapeze when indicated. Use a lift sheet to move the patient. Protect the patient’s elbows, heels, sacrum, and back of head if he or she is exposed to friction.
  • Other general care issues— Do not massage reddened bony prominences and do not use doughnut-type devices. Maintain good hydration and avoid drying out the patient’s skin.


Many clinicians believe that an informal PU risk assessment is sufficient and that a formal risk assessment is not necessary. On the contrary, an informal risk assessment cannot take the place of a formal risk assessment such as one conducted using the Braden Scale. Research has shown that in the absence of formal risk assessment, clinicians tended to intervene consistently only at the highest levels of risk.

For example, in studies, turning—considered an important part of PU prevention—was prescribed for fewer than 50% of patients at mild or moderate risk for developing PUs. Pressure reduction was prescribed more than turning, but not with adequate consistency.

In studies where formal risk assessment was introduced and levels of risk were linked to preventive protocols, the incidence of PUs dropped by 60%11; severity of PUs and cost of care decreased as well. This was likely due to better identification of patients at mild and moderate risk and a more consistent use of preventive interventions for patients in all risk categories.

External agencies that review and accredit health care facilities find the evidence quite compelling that formal prevention and risk assessment programs improve quality of care. In fact, they require facilities to have such programs in place. A facility that does not have a formal program faces not only the possibility of being cited by its accrediting body, but also faces the threat of litigation if its care practices cannot be defended in light of existing standards of care.

A health care agency faced with developing a formal prevention and risk assessment program needs to determine the baseline PU prevalence and incidence prior to implementing the program. Most agencies will form a committee to write protocols that will fit their circumstances. The committee should ensure that the protocols are congruent with the AHCPR clinical practice guideline and the recommendations of other external regulatory agencies that provide oversight for that particular agency. The committee is usually responsible for reviewing chart forms and products related to risk assessment, prevention, and monitoring of PUs. In addition, the committee may be responsible for organizing and conducting staff education and serving as consultants to the staff during implementation of the program.


Pressure ulcer prevention is complex work, but it can make a real difference in patient outcomes. If risk assessment is not a part of the everyday practice in an agency, it is likely that the PU incidence is higher than it should be and that the quality of care is not being provided as consistently as needed to prevent this debilitating complication. Armed with the necessary information to proceed, skin and wound care practitioners should step forward and take a leadership role in this arena.




1. National Pressure Ulcer Advisory Panel. Cuddigan J, Ayello EA, Sussman C, editors. Pressure Ulcers in America: Prevalence, Incidence, and Implication for the Future. Reston, VA: NPUAP; 2001.
2. US Department of Health and Human Services. Healthy People 2010: Understanding and Improving Health. 2nd ed. Washington, DC: US Government Printing Office; November 2000.
3. Panel on the Prediction and Prevention of Pressure Ulcers in Adults. Pressure Ulcers in Adults: Prediction and Prevention. Clinical Practice Guideline No. 3. AHCPR Publication No. 92-0047. Rockville, MD: Agency for Health Care Policy and Research; May 1992.
4. Norton D, McLaren R, Exton-Smith AN. An Investigation of Geriatric Nursing Problems in Hospital. London: National Corporation for the Care of Old People; 1962.
5. Gosnell DJ. An assessment tool to identify pressure sores. Nurs Res 1973; 22( 1):55–9.
6. Bergstrom N, Braden BJ, Laguzza A, Holman V. The Braden Scale for Predicting Pressure Sore Risk. Nurs Res 1987; 36:205–10.
7. Abruzzese RS. Early assessment and prevention of pressure sores. In: Lee BY, editor. Chronic Ulcers of the Skin. New York: McGraw-Hill Co; 1985. p 1–19.
8. Waterlow J. Pressure sores: a risk assessment card. Nurs Times 1985; 81( 48):49–55.
9. Bergstrom N, Braden B. A prospective study of pressure sore risk among institutionalized elderly. J Am Geriatr Soc 1992; 40:747–58.
10. Bergstrom N, Braden B, Kemp M, Champagne M, Ruby E. Predicting pressure ulcer risk: a multisite study of the predictive validity of the Braden Scale. Nurs Res 1998; 47:261–9.
11. Braden B, Bergstrom N. Clinical utility of the Braden Scale for Predicting Pressure Sore Risk. Decubitus 1989; 2( 3):44–51.


The Braden Scale score that signals the onset of pressure ulcer (PU) risk is known as the cut score. In the general adult population, the cut score was originally reported as 16. Further testing by the authors of the Braden Scale and others have resulted in a recommendation that a cut score of 18 be used in clinical practice for many patient populations.

The Braden Scale has been tested in a variety of settings to determine if different scores should be used in different patient populations. In a large study by Bergstrom et al 1, the Braden Scale was used in large tertiary care hospitals, Veteran’s Administration hospitals, skilled nursing facilities, and home care. Others have replicated these findings in similar settings. Although sensitivity and specificity varied slightly among studies, the collective evidence indicates that a cut score of 18 for elderly patients is appropriate in all settings.

In addition, a few researchers have studied the use of the Braden Scale in various ethnic groups. Lyder et al 2 examined the predictive validity of the Braden Scale in a population of African American and Hispanic patients and found a cut score of 18 provided the most accurate prediction of PU risk. Likewise, Pang and Wong 3 studied the predictive validity of the Braden Scale in an Asian population and found a score of 18 provided optimal prediction. Although larger studies may be needed to strengthen these results, it appears that a cut score of 18 is appropriate for all ethnic groups.


The following case study demonstrates how to compute the subscale score for each of the 6 categories on the Braden Scale.

The patient is a 72-year-old man who has right-sided paralysis following a left cerebral vascular accident 2 weeks ago. He can respond to verbal commands but is not always able to speak and say what he needs. He is incontinent of urine, usually at least 3 times a day. Because his ability to walk is greatly impaired, he spends most of the day in a chair. He is unable to change positions by himself and needs assistance with all his activities of daily living. He has difficulty swallowing, lacks an appetite, is unable to use his right arm to feed himself, and is only eating half of his meals.

Using this information, compute the subscale score for each of the 6 categories on the Braden Scale:

  • Sensory Perception. This subscale has 2 levels: The top descriptors measure level of consciousness and the bottom descriptors measure cutaneous sensation. Because this patient can respond to verbal commands but cannot always speak, his score for this subscale category is 3—slightly limited. However, he would score 2 on the bottom level because he is a paraplegic and cannot feel pain over half of his body. If a patient has different scores on each of these levels, the lower of the scores should be used. In this case, the patient would receive a score of 2 for sensory perception.
  • Moisture. Because the patient is incontinent at least 3 times a day, the score for this subscale category is 2—very moist.
  • Activity. The patient is spending most of his day in the chair and not walking; therefore, the score for this subscale category is 2—chairfast.
  • Mobility. Because the patient is unable to make independent changes of position, the score for this subscale category is 1—completely immobile.
  • Nutrition. The patient is eating only half of his food, for a score of 2—probably inadequate —for this subscale category.
  • Friction/shear. Because the patient needs so much assistance in moving and turning, the score for this subscale category is 1—problem.

To obtain the patient’s Braden Scale score, add up the subscale scores. In this case, the patient’s Braden Scale score is 10, indicating that he is at high risk for pressure ulcer development.

© 2002 Lippincott Williams & Wilkins, Inc.