BWAT is a measuring instrument used to assess and monitor healing in pressure ulcers and other chronic wounds.
Development of the BWAT
In 1990, Bates-Jensen1 developed the PSST, which was revised in 2001 as the BWAT. The original PSST was developed as a wound assessment tool for both clinical and research use.
care facilities.19 Total PUSH scores have been used to evaluate pressure ulcer healing among residents in nursing homes.20,21 PUSH scores are responsive to change in ulcer status and can differentiate between ulcers that heal and those that do not.20,21 In prospective studies using the PUSH tool weekly to measure pressure ulcer healing, PUSH scores:
• Were signifi cantly lower among pressure ulcers that healed compared with unhealed ulcers20,21
• Decreased signifi cantly over time among healed ulcers but did not among unhealed ulcers21
• Differentiated between healing and nonhealing ulcers starting with the fi rst week20
• Were highly correlated with scores on the Pressure Sore Status Tool (PSST [now the BWAT]) and surface area measurements21
Use of the PUSH tool does not necessarily correlate with traditional nursing observations and documentation in long-term care settings.22 In 370 observations for 48 nurs- ing home residents with pressure ulcers where both PUSH scores and traditional nursing assessment (primarily ulcer
EXHIBIT 5.3
Summary of Wound Attribute Change over a 5-Week Course of Care
Week 0 Week 2 Week 4
“NOT GOOD”
for healing
“NOT GOOD”
for healing
“NOT GOOD” for healing
Hemorrhage Necrosis Undermining
Undermining Undermining Depth 12, 3, 6, 9:00
Erythema Erythema Undermining 9:00
Necrosis Depth 12, 3, 6, 9:00
Depth 9:00 Undermining 12, 3, 6, 9:00
“GOOD” for healing
“GOOD” for healing
“GOOD” for healing
None Fibroplasia Fibroplasia
Appearance of contraction
Appearance of contraction Sustained contraction Adherence Epithelialization Wound healing
phase
Wound healing phase
Wound healing phase Infl ammatory
phase
Infl ammatory phase
Proliferative phase Source: Copyright © 1997, Sussman Physical Therapy, Inc.
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resulted in lower reliability than the tool’s use by specialists, but still within an acceptable range.27 Predictive validity has also been evaluated. This study involved assessments of 143 pres- sure sores over 6 weeks, with a minimum of three assessments per ulcer during the study period.28 The main outcome measure of the study was time to 50% healing, as measured by surface area. The results showed that changes in the BWAT score at 1 week plus changes in surface area measurements were pre- dictive of those wounds that achieved 50% healing during the 6 weeks compared to those that did not. A 1-week net decrease (improvement) in total BWAT score plus a decrease in surface area was the best predictor of time to 50% wound closure. The positive predictive value of a net improvement in total PSST score at 1 week was 65%, whereas the positive predictive value of a net deterioration in PSST score at 1 week was only 31%.
Sensitivity in this sample was 61%, and specifi city was 52%.28 Thus, the total BWAT score may provide a method of predicting outcomes. More research is needed in this area.
Converting BWAT Scores into PUSH Scores
A PUSH score can be calculated from the BWAT tool and the two tools are highly correlated.21 The following guidelines will enable you to convert BWAT subscale scores into PUSH sub- scale scores. Table 5.4 provides an example of conversion.
1. Wound size: It is best to use actual surface area measure- ments, length by width, to determine which PUSH size Over the years, BWAT use has evolved to include measuring
and predicting wound healing and is used in a wide variety of wounds beyond pressure ulcers. The BWAT has provided a basis for many other wound assessment tools and is the most widely used of the instruments presented. Only minor changes were made to the PSST to create the second generation tool, the BWAT.
Use of the BWAT
The BWAT is recommended for use to assess and monitor healing in pressure ulcers and other chronic wounds. It uses a numerical scale to rate wound characteristics from best to worst possible (see Appendix 5D). Two items are nonscored:
location and shape. The remaining 13 are scored items. These are: size, depth, edges, undermining or pockets, necrotic tissue type, necrotic tissue amount, exudate type, exudate amount, surrounding skin color, peripheral tissue edema, peripheral tissue induration, granulation tissue, and epithelialization.
Each scored item appears with characteristic descriptors rated on a scale (1 indicating best for that characteristic and 5 indi- cating worst). Once a lesion has been assessed for each item on the BWAT, the 13 item scores can be summed to obtain a total score for the wound. The total score can then be plotted on the wound continuum at the bottom of the tool to “see at a glance”
healing or degeneration of the wound. Total scores range from 9 (wound closure) to 65 (profound tissue degeneration). The tool has a one-page sheet of instructions for use, in addition to the item descriptions (Appendix 5D). There is also a pictorial guide for training health professionals in use of the BWAT.24,25 The BWAT Pictorial Guide includes102 photographs of a variety of wound types, not just pressure ulcers, illustrating each descriptor for each of the BWAT items. Validation of the photographic content was accomplished in a three-stage consensus process working with nurses specializing in wound care.24 Figure 5.21 provides an example of a page from the pic- torial guide.
Wounds should be scored with the BWAT initially for a baseline assessment and at regular intervals (i.e., at least weekly) to evaluate intervention effectiveness.
Validity and Reliability of the BWAT
The original items on the BWAT were developed using a modifi ed Delphi process that involved use of a multidisci- plinary panel of experts in pressure ulcers and wound healing.
The expert panel reviewed and developed consensus on the items and descriptors of each item on the tool, format of the tool, and scoring mechanisms. Once developed, the tool was validated through the use of a second expert panel, which established con- tent validity for each individual item on the tool and for the total tool.1 Concurrent validity was established in a study with nurs- ing home residents by comparing total tool scores and the depth item scores with the NPUAP’s staging classifi cation system.26
Reliability of the BWAT was demonstrated on adult patients in an acute care hospital with enterostomal therapy (ET) nurses or nurses with special training in wound care and demon- strated excellent reliability with correlation coeffi cients greater than 0.90.1 Reliability with practitioners who did not have edu- cation or experience in wound assessment and management
FIGURE 5.21 A page from the Bates-Jensen Wound Assessment Picto- rial Guide. (Copyright © B.M. Bates-Jensen.)
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BWAT Items BWAT Scores PUSH Items PUSH Scores
1. Size 4 (6.5 × 6.0 cm = 39 cm2) 1. Size (724 cm2) 10
2. Depth 3
3. Edges 2
4. Undermining 1
5. Necrotic Tissue Type 3
6. Necrotic Tissue Amt. 4
7. Exudate Type 4
8. Exudate Amt. 5 2. Exudate Amt. (Heavy) 3
9. Skin Color 4
10. Edema 1
11. Induration 2
12. Granulation 3 Tissue Typea (Slough) 3
13. Epithelialization 4
Total Score 40 Total Score 16
aNote that necrotic tissue is item 5 on BWAT and 3 on PUSH, where slough is not classifi ed as necrotic tissue if all necrotic tissue is absent.
Example of PUSH Score Derivation from BWAT Scores 5.4
TABLE
category is appropriate. If actual measurements are not available, the following guide may be helpful:
• If BWAT size category = 1, then PUSH size category score
= 0, 1, 2, 3, 4, 5, or 6.
• If BWAT size category = 2, then PUSH size category score
= either 7 or 8.
• If BWAT size category = 3, then PUSH size category score
= either 9 or 10.
• If BWAT size category = 4 or 5, then PUSH size category score = 10.
2. Exudate amount:
• If BWAT exudate amount score = 1, then PUSH exudate amount score = 0.
• If BWAT exudate amount score = 2 or 3, then PUSH exu- date amount score = 1.
• If BWAT exudate amount score = 4, then PUSH exudate amount score = 2.
• If BWAT exudate amount score = 5, then PUSH exudate amount score = 3.
3. Tissue type:
• If BWAT Total Score = 13, then PUSH Type Score = 0.
OR
If Granulation = 1 and Epithelialization = 1, then PUSH Type Score = 0.
• If Necrotic Tissue Type = 4 or 5, then PUSH Type Score = 4.
• If Necrotic Tissue Type = 2 or 3, then PUSH Type Score = 3.
• If Epithelialization < 5, then PUSH Type Score = 1.
• If Granulation < 5 AND Epithelialization = 5, then PUSH Type Score = 2.
CLINICAL WISDOM
Realistic Goal Setting
In some instances, a wound may never heal because of host factors or other contextual circumstances. In this case, an example of a goal might be to maintain the total BWAT score between 20 and 22.
Utility of the BWAT
An additional benefi t associated with the assignment of numeric values to items on the BWAT is that it assists you in setting real- istic goals. Clinical experience shows that not all wounds heal and certainly not always in the same setting. The BWAT allows for more realistic goal setting as appropriate to the health-care setting and the individual patient and wound. For example, the patient with a large, necrotic, full-thickness wound in acute care will probably not be in the facility long enough for the wound to heal completely. However, the tool enables clinicians to set intermediate or secondary goals, such as “Necrotic tissue in the wound will decrease in amount and type.”
As already noted, the BWAT allows for monitoring of improvement or deterioration in individual characteristics, as well as the total score. This in turn enables you to assess the patient’s response to specifi c treatments. For exam- ple, the characteristics of necrotic tissue type and amount may be tracked with exudate type and amount to evaluate
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Mild Severity BWAT score 21–30
Moderate Severity BWAT score 31–40
Critical Severity BWAT score 41–65 Minimal Severity
BWAT score 13–20
FIGURE 5.22 Severity states based on BWAT scores. The goals of therapy are (1) to decrease the overall severity state of the wound and, thus, the BWAT score and (2) to make the decrease in a timely fashion.
There is equal concern regarding severity of the wound and the dura- tion of time that the wound spends in any severity state. (Copyright Barbara Bates-Jensen.)
the response to debridement or infection management. The ability to track wound symptoms such as exudate allows you to evaluate outcomes of interventions designed to alleviate distressing wound symptoms and may be useful for palliative care, wound-related complaints, and when symptoms affect the patient’s quality of life.29
Use of BWAT Scores to Identify Severity State and Guide Treatment
The severity of a wound, as well as overall health status of the patient, can determine the appropriate management approach for healing. Severity states are a measure of the degree of the tis- sue insult or wound burden on the patient. The goals of wound care are to decrease the overall severity status and to make this decrease in a timely fashion. You can use the BWAT to help you identify a wound’s severity state, and thereby guide your care planning.
As shown in Figure 5.22, BWAT scores can be divided into four suggested severity states: total scores of 13–20 indicate minimal severity; 21–30 indicates mild severity; 31–40 is mod- erate severity; and 41–65 is extreme severity. An example of a treatment algorithm for one wound in each of these sever- ity states is presented below. These treatment algorithms are derived from clinical practice guidelines.
BWAT Minimal Severity Scores 13–20
Wounds with a BWAT total score of 13–20 are generally shal- low partial-thickness wounds. Figure 5.23 presents a generic algorithm for treatment for wounds in this severity state. The main goals for wounds in this severity state are to prevent fur- ther damage and to provide a moist wound environment for healing.
BWAT Mild Severity Scores 21–30
Wounds with mild severity include both partial-thickness and full-thickness wounds. Figure 5.24 presents a general treatment algorithm for partial-thickness wounds with mild severity scores. The goals of care for partial-thickness wounds with mild severity scores are to absorb excess wound exudate, maintain a clean wound bed, and maintain a moist environ- ment. Full-thickness wounds with mild severity scores offer more options for treatment because the wound can present as a clean, full-thickness wound or as a wound fi lled with necrotic debris.
BWAT Moderate Severity Scores 31–40
Figure 5.25 is a care plan for a full-thickness wound with necrotic tissue present. The goals of care for full-thickness wounds with moderate severity scores are to obtain/maintain a clean wound bed, provide a moist environment, absorb excess exudate, prevent premature closure, and reduce wound dead space. Wounds with moderate (and mild) severity scores have the most diverse presentations clinically, so choices regarding treatment are numerous.
Figures 5.26 to 5.28 demonstrate general treatment algo- rithms. These algorithms can be used to determine appro- priate care for a variety of chronic wounds with moderate to extreme BWAT severity scores. Wounds in the moderate severity state are predominantly full-thickness wounds such as stage III or IV pressure ulcers. Figure 5.26 presents the case of the full-thickness wound with necrotic debris and large amounts of exudate. Treatment is focused on debridement and absorbing exudate. Figure 5.27 presents the case of the full-thickness clean wound with undermining or dead space, and the treatment focus is on eliminating the dead space and prevention of premature wound closure. The goals of care for wounds in this severity state are to obtain/maintain a clean wound bed, absorb excess exudate, eliminate dead space to prevent premature wound closure, and provide a moist wound environment.
BWAT Critical Severity Scores 41–65
Wounds with BWAT total scores between 41 and 65 are gen- erally deep full-thickness wounds with more critical clini- cal manifestations, including undermining and necrosis.
Figure 5.28 presents an algorithm for treatment of a wound with necrotic eschar. The goals of care for wounds in this severity state are to identify and treat infection, obtain a clean wound bed, absorb excess exudate, eliminate dead space to prevent premature wound closure, and provide a moist wound environment.
Considerations in Using the BWAT Scores to Guide Treatment
The use of the BWAT score for determining severity state and guiding treatment offers one approach to managing wounds.
This approach may be useful in designing broad generic treat- ment guidelines; however, you must still use your clinical judgment to individualize the care plan. Moreover, the treat- ment plans presented based on the BWAT severity scores focus only on topical wound care. Attention to nutrition, use of
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FIGURE 5.23 Minimal BWAT severity score treatment algorithm for mild, dry, partial-thickness wound. (Adapted from ConvaTec, with permission.)
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FIGURE 5.24 Partial-thickness wound with mild BWAT severity score treatment algorithm. (Adapted from ConvaTec, with permission.)
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Re-evaluate plan of care or address underlying etiology if ulcer has not reduced in size during 2 to 4 weeks of care Wound is not infected and is healing as evidenced by a reduction in size
after 2 to 4 weeks of care. No evidence of new skin breakdown.
Secondary Dressing
Reduce risk factors for developing chronic ulcers and delayed healing, e.g.:
Expected Outcomes Delayed Healing
Wound Assessments Observed Goals of
Patient Care
Wound bed/exudate Wound bed/tissue
Depth
Surrounding skin
Wound edges
Goals of Wound Care
Primary Dressing
Patient Care Plan