Use of the PUSH Tool to Measure Venous Ulcer Healing
Wound assessment is critical to monitoring the effectiveness of treatment in chronic wounds. Accurate and comprehensive wound assessment depends on meticulous and consistent clinical observations and quantitative measurements. Regular assessments quantify and document progress and guide further treatment decisions.
Terminology describing wound assessment is not standardized, nor has consensus been reached on the most appropriate wound healing parameters to monitor. In clinical practice, regular wound assessment using the same technique is the only way to monitor healing outcomes.
A tool to assess the healing progress of a venous ulcer over time is lacking. The Pressure Ulcer Scale for Healing (PUSH) tool was introduced in 1997 by the National Pressure Ulcer Advisory Panel (NPUAP) to monitor the healing of Stage II through Stage IV pressure ulcers.1 The PUSH tool consists of three parameters: length x width; exudate amount (none, light, moderate, and heavy); and tissue type (necrotic tissue, slough, granulation tissue, epithelial tissue, and closed). Each parameter is scored and the sum of the scores yields a total wound score. Scores range from 0 (healed) to 17 (worst possible score). Observation of the changes in the direction and magnitude of the score over time indicates whether the wound is healing. Because the PUSH tool involves only three parameters, it is quick and easy to use. The tool and instructions for use are available from the NPUAP website, www.npuap.org.2
No simple, valid, reliable, and practical tool exists for monitoring the process of venous ulcer healing. The purpose of this study was to explore the viability of using the PUSH tool to assess healing in patients with venous leg ulcers.
Measuring healing progress requires evaluating the wound in more than one setting and identifying improvement or deterioration in wound status. Although tools exist that allow for overall wound assessment, few tools to track healing that are accurate, easy to use, and sensitive to change are available.
Thomas et al1 reported on the derivation and validation of the PUSH tool to assess wound healing using a database of 37 patients with pressure ulcers.1 The three factors used to measure wound healing were ulcer surface area, character of exudate, and surface appearance of the ulcer. Wound area was defined as the greatest length across the ulcer measured in a head-to-toe line, multiplied by the greatest width across a horizontal line from right to left. Presence of exudate was defined as the estimated percent of wound surface covered with visible fluid on the wound bed after removing the wound dressing. Surface appearance was defined as the most prevalent type of tissue in the ulcer bed after dividing the wound into four imaginary quadrants. Principal component analysis indicated that surface area, exudate amount, and surface appearance defined the best model of healing (P <0.001).
An additional validation of the PUSH tool to monitor the healing of Stage II through Stage IV ulcers was reported by Stotts et al3 and involved two retrospective studies (N = 103 and N= 269). Principal components analysis confirmed that the PUSH tool accounted for 58% to 74% of the wound healing variance over a 10-week period in study 1 and 40% to 57% of the wound healing variance over a 12-week period in study 2. In addition, multiple regression analysis used to measure the sensitivity of the model to total healing showed PUSH accounted for 39% of the variance in 6 weeks and 31% of the variance over 12 weeks (P < .001). Based on these data, the two studies confirmed that the PUSH tool is a valid and sensitive measure of pressure ulcer healing.
Jones et al4 did a multiple baseline analysis across nine spinal cord injured patients with pressure ulcers using the PUSH tool to compare severity of pressure ulcers; treatment costs during baseline and intervention also were considered. Average PUSH scores were substantially lower during the intervention phase than at baseline by an average of 10.5 points per participant.
Pompeo5 reported on a prospective cohort study conducted at two long-term care facilities where admission and discharge PUSH scores from 374 patients (989 wounds) were obtained and recorded to document overall progress of healing and to calculate healing as a function of time. For the purpose of this study, the author defined the PUSH score as a change in the patient’s admission and discharge PUSH scores. For patients with multiple wounds, the admission PUSH scores of each of the wounds were added together to get a total score. These patients had an average of 2.65 wounds each and an average PUSH score of 26 on admission and 16 on discharge. Thus, the mean change in PUSH score was 10. The average number of inpatient days per patient was 36.7, resulting in an average change in PUSH score per day (which the authors defined as a PUSH Healing Rate) of (10/36.7) = 0.27. The average change in PUSH score per ulcer (10/2.65) = 3.77. The authors used this data to benchmark and compare healing outcomes in additional facilities to gauge the effectiveness of care.
The literature on venous ulcer healing suggests that the three parameters used in the PUSH tool also may be important in monitoring the status of venous ulcers. Margolis, Berlin, and Strom6 did a retrospective cohort study of 260 patients with chronic venous ulcers and defined risk factors associated with the failure of a patient’s ulcer to heal within 24 weeks while using compression therapy. Failure of the ulcer to heal within 24 weeks was associated with 1) the initial area of the wound (size); 2) whether more than 50% of the wound was covered in fibrin (tissue type); 3) the duration of the wound; 4) a history of vein stripping; 4) a history of hip or knee surgery; and 5) an ankle-brachial index <0.80.
Two other studies indicate that change in venous ulcer size is predictive of healing. van Rijswijk et al7 monitored the healing of 61 patients with 72 full-thickness leg ulcers. They found that a >30% reduction in ulcer area after 2 weeks of treatment was a significant (P = 0.004) predictor of the time required for healing. The authors also reported that increased amounts of exudate at baseline appreciably increased the time to reach 50% or 80% healing compared to wounds without exudate. Subsequently, Kantor and Margolis8 conducted a cohort study of 104 patients and found that the percentage of change in ulcer area during the first 4 weeks of treatment was the best prognostic indicator that the ulcers would eventually heal within 24 weeks.
These reports involving venous ulcer healing would suggest that the same parameters of size, exudate, and tissue type found to be sensitive for monitoring change in pressure ulcers may be equally as important in monitoring venous ulcer status change over time.
This descriptive study addressed the use of the PUSH tool to measure venous leg ulcer healing over a 2-month period. All patients with venous leg ulcers seen in the chronic wound clinic at a major university were assessed and given a PUSH score on the initial visit to the clinic and at subsequent clinic visits. For patients with multiple ulcers, the largest ulcer was selected for inclusion in the study. Two WOCNs completed the PUSH tool; inter-rater reliability of the tool was established with the initial use of the tool by having the two WOCNs rate five patients with venous ulcers and comparing the results. Both WOCNs agreed on the PUSH scores for each of the five patients (100% agreement).
The PUSH tool requires the wound specialist to assess the wound and assign the appropriate score for the three parameters of size, exudate amount, and tissue type (see Figure 1). When these three parameters are scored, the final PUSH score ranges from 0 (healed) to 17 (most severe wound). The PUSH score should be determined and reported at each wound assessment in order to monitor change in wound status.
Twenty-seven patients with venous ulcers were followed monthly for 2 months using the PUSH tool at each visit. The age range of the patients was 29 to 89 years (mean age 63 years); 21 women and six men participated. The largest ulcer was 11.5 cm x 7.5 cm on the initial visit to the clinic; the smallest ulcer was 0.3 cm x 0.3 cm. Of the 27 ulcers included, 20 occurred on the left leg and seven on the right leg.
The mean PUSH score on the first visit was 12, on the second visit 9, and on the third visit 8 (see Table 1 and Figure 1). Of the 27 patients, 23 had a decrease in their PUSH score over the 2-month period; of these, four had PUSH scores of zero at 2 months because their venous ulcers had healed. In reviewing the charts of the four patients whose wounds did not show a decrease in their PUSH score over time, noncompliance with compression therapy appeared to be the reason for nonhealing.
Measuring progress toward healing is fundamental to the management of wounds such as venous leg ulcers. A specific tool to assess healing of venous ulcers is lacking. The National Pressure Ulcer Advisory Panel developed the PUSH tool to measure pressure ulcer healing. The key element of the success of the tool is its simplicity for use in the clinical setting. The tool assesses surface area, exudate amount, and tissue type — important parameters in the assessment of venous ulcers.
Individual analysis of each subject’s venous ulcer was conducted to determine whether the healing trend was consistent over time. The mean scores were different, indicating a sensitivity to change, and scores were consistent with outcome — ie, healing venous ulcers had a decrease in score and nonhealing venous ulcers had an increase in score. Failure of an ulcer to improve on any of the three PUSH variables (size, exudate, tissue type) should alert the clinician that the treatment plan needs to be evaluated. In this study, the vast majority (23 out of 27) of the ulcers improved and all three parameters of the PUSH score decreased with time, documenting ulcer improvement. One of the potential benefits of using the PUSH tool is that a wound clinic can compare monthly patient outcomes within its own program as well as benchmark with other wound centers.
The average healing score per ulcer is a measure of the efficacy of the clinic to heal wounds. In addition, it also takes the rate of improvement into account as the PUSH score decreases. However, the tool cannot provide specific information about the effectiveness of specific interventions.
Although this study is limited by the relatively small sample size, it offers quantifiable results that provide a feasible way to assess healing.
This paper describes the use of the PUSH tool on venous ulcer patients to measure healing outcomes. The PUSH tool represents an excellent starting point to validate healing of venous ulcers, fulfilling a need for a simple, valid, reliable, and practical tool for monitoring the process of venous ulcer healing.