A homebound individual has developed a pressure sore on the heel resulting in eschar formation. Possible contributing factors include obesity, sedentary lifestyle, difficulty with activities of daily living and transfers, oral steroid regimen at the time of sore development and anti-embolism stockings worn daily to control edema in both legs.

What is the likelihood that the eschar formation occurred over a short period of time? Additionally, are iodine preparations (Betadine) used to paint the intact eschar formation before covering the wound with a dressing? In the past, Betadine was noted to be cytotoxic and could delay wound healing. — Geri L. Myles, RN, MSN, ANP, Denver

The use of povidine-iodine in wound care is controversial. Several experimental studies have demonstrated concerns regarding its safety and effect on wound healing.

Povidine (10%) was found to have a toxicity index of 100,000 (the most cytotoxic) in a study of the cytotoxic effects of skin and wound cleansers on epidermal keratinocytes (Adv Skin Wound Care. 2005;18:373-378).

Another study evaluating cytotoxicity of antiseptic medications using human skin substitutes observed that the application of Betadine resulted in a substantial decrease in cell viability and a detrimental effect on tissue histology (Br J Dermatol. 2007;157:33-40). More recently, an investigation into the mechanism of delayed wound healing by commonly used antiseptics demonstrated that povidine-iodine reduced both migration and proliferation of fibroblasts in a dose-dependent fashion (J Trauma. 2009;66:82-90).

In 2010, however, the Cochrane Central Register of Controlled Trials evaluated five trials of povidine iodine and concluded that further good quality research is required before definitive conclusions can be made about the effectiveness of topical povidine-iodine in healing venous leg ulceration (Cochrane Database Syst Rev. 2010;1:CD003557). — Philip R. Cohen, MD (153-08)