Surface acoustic wave patch therapy affects tissue oxygenation in ischemic feet

Transcutaneous oxygen pressure (TcPO2) less than 30 mm Hg at the toe leads to local tissue hypoxia and nonhealing wounds. Studies regularly illustrate that TcPO2 values are strong predictors of healing and can accurately demonstrate altered levels when extremities have restricted blood flow. The objective of this study was to evaluate the effectiveness of surface acoustic wave (SAW) in ischemic feet on local tissue oxygenation.

Ten patients, ranging from 40-75 years of age and suffering from critical limb ischemia (CLI) were selected from a vascular surgery clinic to undergo evaluation with a PainShield SAW Patch device (NanoVibronix Inc, Melville, NY). Patients were treated once with 96 Khz of SAW for 30 minutes. All patients had an ankle brachial index of < 0.4 mm Hg. Two patients (patients 1 and 8) had necrosis of at least 2 toes on the affected limb and were given the device for nightly use for 1 month.

Through usage of SAW there was a significant increase in all patients' saturation values. The recorded baseline in both patients with necrotic toes almost doubled and during usage there was still a measurable increase in oxygen saturation. In both of these patients the subjective pain measures dropped significantly. Pain, as assessed by the Visual Analog Scale, dropped from 9 to 2 for patient 1 and from 8 to 3 for patient 8. Patient 1 went from 5 methadone treatments per day to only 1 per day starting in week 3. Patient 8 did not change their pain medication regimen.

Surface acoustic waves as delivered in this study had a positive effect on tissue oxygenation and saturation in ischemic feet. In lower extremities that are not surgical candidates or are either in the pre- or postsurgical environment, an SAW patch device is a good therapy in elevating the extremities' O2 saturation.