Cath Lab Digest

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Pressure ulcers are localized skin injuries secondary to unrelieved pressure or friction. Patients with immobility issues are at increased risk for developing pressure ulcers. In 2004, stricter federal regulations for prevention and treatment of pressure ulcers in institutional settings — eg, long-term care facilities — were introduced. Effective, low-cost treatments for pressure ulcers are needed; acoustic pressure wound therapy (APWT), a noncontact, low-frequency, therapeutic ultrasound system, is one option. A retrospective case series of six long-term care patients (two men and one woman, age range 61 to 92 years), each with one Stage II pressure ulcer, is presented. Acoustic pressure wound therapy was provided as an adjunct to standard treatment that included balsam of Peru/castor oil/trypsin ointment, hydrogel, hydrocolloid dressings, silver dressings, and offloading. Outcomes (days to healing) were determined through changes in wound dimensions. Study participants each received APWT for 3 to 4 minutes three to four times weekly. In four of the six wounds, the average number of days to healing was 22. One of the two remaining patients discontinued treatment at 95% healed; treatment for the sixth patient was ongoing due to hospitalization that delayed APWT. In a long-term care setting, APWT added to standard of care may accelerate healing of Stage II pressure ulcers.

KEYWORDS: acoustic pressure wound therapy; pressure ulcer; wounds

     Pressure ulcers (PU) are localized skin injuries, typically over a bony prominence, that develop as the result of unrelieved pressure, friction, or shear. They range from intact reddened skin (Stage I) to exposed bone (Stage IV).¹ Pressure ulcers can become chronic, debilitating, painful, and life-threatening. They are a common problem in patients with reduced mobility.^2,3 Patients in long-term care (LTC) facilities are at an increased risk of developing PUs. In the nursing home setting, the median time to heal a Stage II PU has been found to be 46 days.⁴ In 2004, stricter federal guidelines for the prevention and treatment of PUs in LTC facilities were instituted,² increasing the economic burden of PUs in this setting.

     Acoustic pressure wound therapy (APWT; MIST® Therapy System; Celleration, Eden Prairie, Minn) is a noncontact, low-frequency, nonthermal ultrasound therapy delivered via sterile, saline mist. The acoustic energy stimulates wound healing at the cellular level⁵ and cleanses and debrides wounds. A growing body of clinical literature has described the effectiveness of APWT in studies of acute and chronic wounds. ⁶ Some clinical evidence also suggests that APWT reduces wound-related pain and in vitro data found that APWT destroys bacterial cells.^7,8

     Because of increasingly stricter federal regulations for PUs,² the author’s LTC facility recently added APWT to standard of care for Stage II PUs. This six-patient case series describes the outcomes of APWT in the treatment of Stage II PUs in LTC residents with impaired mobility.

Methods

     Data were collected retrospectively from the medical records of six nonconsecutive patients. This is a representative sample of patients with Stage II pressure ulcers treated with APWT and standard of care at this LTC facility. Patients or their legal guardians provided informed consent for treatment and inclusion in this case series. Patients were treated with APWT as an adjunct to standard wound care that included balsam of Peru/castor oil/trypsin ointment, hydrogel, hydrocolloid dressings, and silver dressings and pressure-relieving devices such as mattresses and wheelchair cushions to provide offloading. The effect of APWT was assessed through changes in wound dimensions.