Wound healing. New modalities for a new millennium.

Common to all studies of wound healing modalities is the need to convert the chronic wound into an acute wound and to maintain the wound in an acute state while subsequently using adjunctive therapy. Hence, precise control and documentation of wound care is extremely important in order to avoid contamination of the effects of a specific modality with the effects of good wound care. Falanga has noted that neuropathy of diabetes has been given wide support as the primary pathogenic component of diabetic ulcers, whereas less recognition has been made of the wound-healing failure component. The therapies discussed in this article considered the wound-healing failure component. Oxygen is a drug. The use of oxygen under normobaric conditions at higher than normal inspired partial pressures is standard operating procedure when clinicians are faced with patients with respiratory embarrassment or heart failure. The use of oxygen under hyperbaric conditions, however, remains estranged from the mainstream thoughts of most clinicians. Abnormally hypoxic wounds may benefit from specific oxygen therapy in hyperbaric dosage ranges. However, correction of abnormal wound oxygen tension alone does not guarantee healing. Hyperbaric studies have been criticized for the lack of well-defined wound care protocols, the absence of precise wound healing measures, and poorly defined wound healing endpoints. Studies with growth factors and human skin equivalents exclude patients typically referred for hyperbaric therapy. Patients referred for hyperbaric therapy often have larger wounds with greater severity of peripheral vascular disease with ABIs < 0.7 and TcPO2 < 30 to 40 mm Hg, are often on medications known to inhibit wound healing (e.g., steroids), or have concomitant medical disorders (collagen vascular disease, renal failure) associated with poor healing. No hyperbaric study has controlled stringently for all of these factors. Nevertheless, HBO2 is more specific and successful for the intended purpose of correction of abnormal tissue oxygen tensions than are growth factors for the intended purpose of growth. Similarly, skin substitutes are limited in their application and have not been tried in patients with ABIs < 0.7 or TcPO2 values < 30 mm Hg. In our view, hyperbaric therapy probably can be combined successfully with allogenic grafts and human skin equivalents in this group of patients. Hyperbaric therapy can generate a sufficient granulation base in which these products should be able to close properly selected wounds successfully. No studies of this combined modality approach exist. Finally, regardless of the modality used to aid in wound closure, long-term outcomes probably depend more on neuropathy and large vessel disease than on microangiopathy and local wound-healing defects. The modalities presented in this article must prove to be both cost effective and practical before they are widely disseminated. Nevertheless, the ability to manipulate the local wound environment is no longer inviolate as was once presumed, and current investigations continue to advance therapeutic options in this most fascinating and challenging discipline.