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

OBJECTIVE: The primary aim of this research was to investigate the combination effect of polyhexamethylene biguanide (PHMB) and low-frequency contact ultrasonic debridement (LFCUD) on the bacterial load in hard-to-heal wounds in adults, compared with ultrasonic debridement alone. Secondary outcomes included wound healing, quality of life (QoL) and pain scores. METHOD: In this single-blinded, randomised, controlled trial participants were randomised to two groups. All participants received LFCUD weekly for six weeks, plus six weeks of weekly follow-up. The intervention group received an additional 15-minute topical application of PHMB post-LFCUD, at each dressing change and in a sustained dressing product. The control group received non-antimicrobial products and the wounds were cleansed with clean water or saline. Wound swabs were taken from all wounds for microbiological analysis at weeks 1, 3, 6 and 12. RESULTS: A total of 50 participants took part. The intervention group (n=25) had a lower bacterial load at week 12 compared with the control group (n=25) (p<0.001). There was no difference in complete wound healing between the groups (p=0.47) or wound-related QoL (p=0.15). However, more wounds deteriorated in the control group (44%) compared with the intervention group (8%, p=0.01). A higher proportion of wounds reduced in size in the intervention group (61% versus 12%, p=0.019). Pain was lower in the intervention group at week six, compared with controls (p=0.04). CONCLUSION: LFCUD without the addition of an antimicrobial agent such as PHMB, cannot be recommended. Further research requires longer follow-up time and would benefit from being powered sufficiently to test the effects of multiple covariates.

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.