Use of low-frequency contact ultrasonic debridement with and without polyhexamethylene biguanide in hard-to-heal leg ulcers: an RCT protocol

Objective: The purpose of this research is to investigate the effect of low-frequency contact ultrasonic debridement therapy (LFCUD) in hard-to-heal wounds with suspected biofilm, and compare the effect with or without a surfactant antimicrobial on bacterial colony counts and wound healing rates. Method: A single-blinded randomised controlled trial (RCT) will investigate the combination of LFCUD and the antiseptic polyhexamethylene biguanide with a surfactant betaine (referred to in this paper as PHMB) as a topical solution post-treatment and in a sustained dressing, compared with use of LFCUD alone. Potential participants from a community wound clinic (n=50) will be invited to take part in the 12-week trial. Wound swabs and tissue samples will be analysed for bacterial type and quantity, before and after treatments, using traditional culture techniques and advanced molecular methods. Wound healing, pain, quality of life and biofilm (via a specifically designed tool) will also be measured. Discussion: Bacteria have the potential to cause a hard-to-heal wound, particularly when antibiotics are too frequently and unnecessarily prescribed, resulting in antibiotic-resistant microorganisms. Appropriate care is vital when caring for hard-to-heal wounds to avoid these scenarios. With no simple laboratory method available to identify or treat wound biofilm, clinicians rely on their expertise in wound management. This study aims to provide in vivo evidence on the effectiveness of PHMB, to prevent the reformation of biofilm when applied after LFCUD. The aim is to provide evidence-based and more cost-effective wound care.