Cath Lab Digest

The presence of pressure ulcers in elderly patients is a widespread problem that results in considerable healthcare costs.^1-3 For example, the incidence of Stage II and worse pressure ulcers has been reported to be more than 30% in nursing home residents.¹ Therapeutic ultrasound (US) is one of several treatment methods used to enhance healing of pressure ulcers, including sharp debridement, wound cleansing, wound dressings, and electrical stimulation.³ Under in vivo and in vitro conditions in animal studies, ultrasound has been shown to have beneficial effects on factors associated with tissue healing. These effects include promotion of histamine release⁴ and mast cell degranulation,^4,5 angiogenesis,⁶ increases in intracellular calcium,⁷ increases in collagen deposition and wound-breaking (or tensile) strength,^8-10 and reduction of wound size.⁵

The limited clinical research that has been conducted on human subjects seems to be split as to the efficacy of US on both venous ulcers and pressure ulcers in the elderly,^11-16 and data regarding full-thickness pressure ulcers in the elderly are particularly scarce.

The purpose of this study was to assess the efficacy of pulsed low-intensity ultrasound (LIUS) for healing a Stage III pressure ulcer in a geriatric patient. A Stage III ulcer was chosen for study because it is a full-thickness skin loss,³ which would enable the authors to note healing by measuring the surface area as it closed. A Stage II ulcer was not chosen because the authors believed the wound edges would be less discernible for reliable wound tracing. Pressure ulcers at Stage IV were not chosen because the damage in each wound extends to the muscle, bone, or supporting structures³; thus, requiring additional measurements such as wound volume.

Literature Review

Studies have reported mixed results on the efficacy of pulsed LIUS for wound healing in humans. Comparisons are difficult because of differences in US parameters; standard care characteristics; other treatment protocol variables; differences in type, size, and location of ulcers; and ambiguous descriptions of ulcer status or stage.

Dyson and Sucklin¹⁶ reported on two different trials involving patients with chronic varicose ulcers of the lower limb (reportedly chosen because of their superficial nature) that had never been treated with US and had not responded favorably to other types of treatment. All patients received the same form of standard care. One trial separated the patients into groups receiving pulsed US or placebo US; for patients with bilateral ulcers, one received pulsed US while the other received placebo US. In the other trial, an ulcer was treated with placebo US for the first month and pulsed US for the second month. Ultrasound characteristics were: 3 MHz, 1.0 W/cm², pulsed 20%, 7.07 cm² ERA, 5 minutes for ulcers of 2.5cm² or less with 1 minute added for each additional 0.5 cm² up to 10 minutes, three times a week. In the first trial, after the first 4 weeks, the pulsed US group had a 25% greater reduction in wound surface area than the placebo US group (statistically significant; P <0.05). In the second trial, a significantly greater reduction occurred in wound surface area after the period of pulsed US (34% average) compared to the period of placebo US (14% average); P <0.05.