A randomized controlled trial to investigae the effects of low frequency (22.5kHz) contact ultrasound debridement on healing in a vascular surgery patient population

Purpose

To determine whether 22.5 kHz low frequency contact ultrasound debridement (LFCUD) applied in a nurse-led vascular wound clinic improves lower extremity wound healing in people with peripheral vascular disease (PVD).

Design

Randomized controlled clinical trial; single blinded.

Methods

Consecutively sampled adults (n = 68) with below knee, full thickness wounds > 1cm2 and followed by the Vascular Surgery service were stratified based on negative pressure wound therapy and randomly assigned to standard wound care (SWC) which included conservative sharp debridement,  or LFCUD plus SWC. Healing was determined incorporating baseline data as covariates, to calculate percentage reduction in wound surface area (%WSA) and change in wound appearance (revised Photographic Wound Assessment Tool: revPWAT) after 4 weekly treatments of SWC, or LFCUD + SWC.

Results

The mean %WSA reduction post-treatments (Week 5) was greater (31.63%) in the LFCUD group than  in the SWC group  (18.06%) but this finding was not statistically significant (p = 0.485). Wound appearance was significantly improved (p = <0.01) in the LFCUD group which declined by 7.34 revPWAT points (5.8 – 8.9, 95% CI) compared to SWC group of 2.98 revPWAT points (1.4 – 4.6, 95% CI). By Week 5 only LFCUD patients had closed wounds (n = 2) or were ready for skin grafting (n = 2).

Conclusion

LFCUD improves wound appearance in patients with PVD, supports closure and is suitable for nurse application.