Objective: This randomised controlled clinical trial compared a capillary dressing (Drawtex, now rebranded as Vibriant RCD [Vibriant Technology Services]) with routine practice for exuding wounds greater than 2.5 x 2.5 cm.
Method: The target population was 300 control and 300 test subjects across three sites in the UK, but recruitment difficulties resulted in only 125 patients being evaluable. Wound progress was recorded by nurses' perception of the progress of wound healing and by objective digital imaging. In the final analysis digital images were randomised (in time order) and a panel of nurses who were not otherwise involved in the research project graded the wound's progress.
Results: After deconvolution of the data, the subjective (nurse perception) method of evaluation determined that the new dressing resulted in wound improvement in 12.7% more patients than did routine practice, but the blinded assessment method (based on the digital images) showed that routine practice was better by 6.6%.
Conclusion: Evaluation of wound progress is clearly difficult. Human nature makes us favour novelty if we believe it is going to be better. Making interpretation more objective removed that bias and did not demonstrate a significant advantage for the test dressing. The findings suggest that unblinded assessment by trial nurses is unacceptable on its own. Blinded assessments may miss finer nuances of wound progression, but are likely to be more accurate. The authors suggest that the true result lies somewhere in the middle, with the trial dressing likely to be as effective as, but not more effective than, a standard dressing.