to the lack of high-quality research in these areas. Other prevention therapies A Cochrane systematic review found use of creams containing fatty acids may be more effective in reducing incidence of pressure ulcers compared to creams without fatty acids. Silicone dressings may also reduce pressure ulcer incidence. There is no evidence that massage reduces pressure ulcer incidence. Treatment Internationally, the NPIAP, EPUAP and Pan Pacific Pressure Injury Alliance, together with wound organizations from 15 countries around the world published updated their international evidence-based clinical practice guideline in 2019. The 2019 guideline was developed by an international team of over 180 clinical specialists and updates the 2009 EPUAP/NPUAP clinical guideline and the 2014 NPUAP/EPUAP/PPPIA clinical guideline. The guideline includes recommendations on strategies to treat pressure ulcers, including the use of bed rest, pressure redistributing support surfaces, nutritional support, repositioning, wound care (e.g. debridement, wound dressings) and biophysical agents (e.g. electrical stimulation). Reliable scientific evidence to support the use of many of these interventions, though, is lacking. More research is needed to assess how to best support the treatment of pressure ulcers, for example by repositioning. A 2020 Cochrane systematic review of randomized controlled trials concluded that more research is needed to determine whether or not electrical stimulation is an effective treatment for pressure ulcers. In addition, the benefit of using systemic or topical antibiotics in the management of pressure ulcer is still unclear. Debridement Necrotic tissue should be removed in most pressure ulcers. The heel is an exception in many cases when the limb has an inadequate blood supply. Necrotic tissue is an ideal area for bacterial growth, which has the ability to greatly compromise wound healing. There are five ways to remove necrotic tissue. Autolytic debridement is the use of moist dressings to promote autolysis with the body's own enzymes and white blood cells. It is a slow process, but mostly painless, and is most effective in individuals with a properly functioning immune system. Biological debridement, or maggot debridement therapy, is the use of medical maggots to feed on necrotic tissue and therefore clean the wound of excess bacteria. Although this fell out of favor for many years, in January 2004, the FDA approved maggots as a live medical device. Chemical debridement, or enzymatic debridement, is the use of prescribed enzymes that promote the removal of necrotic tissue. Mechanical debridement, is the use of debriding dressings, whirlpool or ultrasound for