Ultrasound-mediated oxygen delivery to lower extremity wounds

Critical limb ischemia (CLI), an end result of peripheral ar- terial disease, remains a major clinical challenge. Wound healing in patients with CLI can be difficult due to diminished tissue oxygen- ation, often leading to recalcitrant ulcers and frequent limb loss. Nu- merous therapies, including hyperbaric oxygen therapy (HBOT), have been used to correct this regional ischemia, although often with mixed results. This case series investigates the effects of oxygen therapy de- livery augmented by low-frequency ultrasound, a device that combines surface acoustic waveform (SAW) low-frequency ultrasound with hyper- oxygenated saline to deliver oxygen to wounds. Participants included 7 patients (7 men, median age 63 years, all with hypertension) with CLI and full-thickness wounds. Baseline therapy PaO2 measurements were taken before therapy, after provision of hyper-oxygenated saline, and after sonification. The device was found to successfully oxygenate the wound beds; PaO2 levels increased by a median of 59.7%, a maximum of 116%, and a median absolute difference peaking at 10.8 mmHg PaO2 (P = 0.018). In conclusion, the treatment increases wound oxy- gen levels and may be an option in CLI therapy.