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Topical negative pressure for treating chronic wounds.

BACKGROUND
Chronic wounds mainly affect the elderly and those with multiple health problems. Despite the use of modern dressings, some of these wounds take a long time to heal, fail to heal, or recur, causing significant pain and discomfort to the person and cost to health services. Topical negative pressure is used to promote healing of surgical wounds by using suction to drain excess fluid from wounds.


OBJECTIVES
To assess the effectiveness of topical negative pressure (TNP) in treating people with chronic wounds and to identify an optimum TNP regimen.


SEARCH STRATEGY
The Cochrane Wounds Group Specialised Trials Register was searched until July 2000. Experts in the field and relevant companies were contacted to enquire about ongoing and recently completed relevant trials. In addition citations within obtained papers were scrutinised to identify additional studies.


SELECTION CRITERIA
All randomised controlled trials which evaluated the effectiveness of TNP in treating chronic wounds were considered.


DATA COLLECTION AND ANALYSIS
Eligibility for inclusion, data extraction and details of trial quality was conducted by two reviewers independently. A narrative synthesis of results was undertaken as only two small trials fulfilled the selection criteria and they used different outcome measures.


MAIN RESULTS
Two small trials with a total of 34 participants evaluated the effectiveness of TNP on chronic wound healing. Trial 1 considered patients with any type of chronic wound; Trial 2 considered patients with diabetic foot ulcers only. The trials compared TNP (as open cell foam dressing with continuous suction) for the first 48 hours with saline gauze dressings. Trial 1 reported a statistically significant reduction in wound volume at 6 weeks in favour of TNP. Trial 2 (continuous suction, followed by intermittent suction after 48 hours) reported a reduction in the number of days to healing and a reduction in wound surface area at 2 weeks in favour of TNP, - although no statistical analysis was reported.


REVIEWER'S CONCLUSIONS
The two small trials provide weak evidence suggesting that TNP may be superior to saline gauze dressings in healing chronic human wounds. However, due to the small sample sizes and methodological limitations of these trials, the findings must be interpreted with extreme caution. The effect of TNP on cost, quality of life, pain and comfort was not reported. It was not possible to determine which was the optimum TNP regimen.