Does Debridement Improve Clinical Outcomes in People With Diabetic Foot Ulcers Treated With Continuous Diffusion of Oxygen?

Lawrence A. Lavery, DPM, MPH; Mark Q. Niederauer, PhD; Klearchos K. Papas, PhD; David G. Armstrong, DPM, MD, PhD

Disclosures

Wounds. 2019;31(10):246-251. 

In This Article

Abstract and Introduction

Abstract

Objective: This post hoc analysis evaluates the association between the frequency of diabetic foot ulcer (DFU) debridement and the proportion of ulcers treated with active continuous diffusion of oxygen (CDO) that heal in a 12-week evaluation period.

Materials and Methods: There were 146 patients with DFUs (77% men; average age, 56.3 ± 12.4 years) enrolled in a double-blind, placebo-controlled, randomized study to receive either active CDO or an otherwise fully operational placebo device. Patients were followed for 12 weeks or until wound closure. All patients received identical offloading, dressings, and follow-up. Ulcer debridement was left to the discretion of the treating physician and recorded from physician self-report as a dichotomous variable.

Results: A significantly higher proportion (204%) of ulcers healed in the CDO group compared with the placebo (46.2% vs. 22.6%, respectively; P = .016). The relative performance of active CDO over placebo became greater when frequent debridement was used (51.2% vs. 21.3%, respectively; P = .006).

Conclusions: A significantly greater percentage of healing was recorded in patients receiving active CDO therapy than those receiving a placebo device in addition to standard wound care with identical dressings, debridement recommendations, and offloading. The relative performance of CDO appears to increase with the use of frequent debridement.

Introduction

There is a worldwide epidemic of diabetes and diabetes-related complications. Foot ulcers are one of the most common complications in patients with diabetes, leading to amputation and hospitalization.[1–3] While a variety of treatments have been associated with diabetic foot ulcer (DFU) healing, debridement, including enzymatic, autolytic, larval, and surgical, is one of the most common components of the DFU treatment plan.[4,5] There are several theoretical reasons to debride a DFU. Debridement changes the wound environment by removing necrotic debris, senescent cells, infected tissue, and biofilm that may impair healing. At the same time, debridement can convert a stagnant, chronic ulcer to a more biologically active acute wound.[6]

Several studies[4,7,8] have suggested DFUs receiving serial surgical debridement heal faster and a higher proportion of these DFUs heal. For instance, Steed et al[7] reported data from a post hoc analysis of a multicenter, randomized, controlled trial (RCT) studying topically applied recombinant human platelet-derived growth factor (rhPDGF) versus a placebo that showed centers with the highest rates of DFU healing had the highest frequency of debridement, and centers with the lowest healing rates had the lowest rates of debridement among patients who received rhPDGF. Similarly, among patients who received the placebo, sites with the lowest debridement had the lowest healing rates.[7] Even though there are important limitations to previous studies,[4,7,8] the body of work in this area supports the importance of debridement as a component of the overall DFU treatment strategy. Wilcox et al[8] reviewed the serial surgical debridement of nearly 155 000 patients with more than 312 000 total wounds. They[8] identified a healing rate more than 3-fold greater in people with chronic wounds debrided weekly than those treated less often. While aforementioned works have suggested a positive healing signal through the use of serial debridement and many guidelines endorse the practice,[9–11] a relative paucity of evidence to support its use still exists.

Oxygen has been shown to be an essential component in multiple mechanisms of action required for wound healing.[10–12] Depressed levels of oxygen have been shown[13,14] to be a rate-limiting step in these mechanisms. Conversely, increasing oxygen levels has been shown[13,14] to result in increased, and often proportional, levels of activity in these mechanisms of action. Aside from general cell metabolism and energy production, these mechanisms of action, and corresponding rates of action, affected by oxygen levels in the tissue include cell proliferation and reepithelialization,[13,15] collagen synthesis and tensile strength,[14,16,17] angiogenesis,[18,19] antibacterial activity through respiratory burst,[20–22] and growth factor signaling transduction.[23,24] Damaged tissue in chronic wounds has increased oxygen demands and can achieve improved healing through enhancement of local oxygen availability with oxygen therapy.[22,25,26]

Continuous diffusion of oxygen or continuously diffused oxygen (CDO) uses pure, humidified oxygen to treat a wound by continuously supplying oxygen directly to the affected tissue within a moist wound therapy (MWT) dressing; simply put, CDO is MWT plus oxygen. This allows for sustained delivery of oxygen to the tissue (24 hours daily, 7 days weekly), full patient mobility during treatment, and application of the therapy in virtually any setting. In CDO therapy, oxygen is introduced into the wound bed through the dressing and into the surface of the tissue. Anything that can impair the transport of oxygen into the wound bed, such as slough or eschar, theoretically would negatively impact the effectiveness of CDO therapy. Aggressive debridement removes or minimizes these barriers to oxygen transport and would allow the optimal transport of oxygen into the tissue.

The aim of this study is to evaluate the association between DFU debridement and the proportion of ulcers that heal with and without active CDO therapy in a 12-week evaluation period.

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