An Observational Clinical Trial Examining the Effect of Topical Oxygen Therapy (Natrox <sup>™</sup> ) on the Rates of Healing of Chronic DiAbetic Foot Ulcers (OTONAL Trial)
Tjun Yip Tang, Manfred Mak, Charyl Jia Qi Yap, Johnson Boey, Sze Ling Chan, Shereen Xue Yun Soon, Izza Atiqa Ishak, R. W. L. Lee, Xin Jie Soh, Wan Xi Goh
Abstract
Natrox ™ topical oxygen therapy (TOT) ( Inotec AMD Ltd, Cambridgeshire, UK) employs a small battery-powered “oxygen generator” to concentrate atmospheric oxygen and feeds pure, moist, oxygen through a fine, soft tube to a dressing-like “oxygen distribution system”, which is placed over the wound and is held in place by a conventional dressing. The aim was to determine the effectiveness of Natrox ™ for non-healing diabetic foot ulcers (DFU) over a 3-month period.Longitudinal, single-arm, open prospective registry study using 12 weeks of TOT using a 4 week run-in period. 20 patients recruited to OTONAL had chronic DFU greater than 3 months duration or minor amputation sites with less than 50% healing in 4 weeks.There were 13 (65%) males and the mean age was 65.7 (±11.6) years. The mean glycated haemoglobin (HbA1c) was 6.9 (±1.3) mmol mol −1 and mean wound duration before TOT was 114 (±79.1) days. 18/20 (90.0%) patients had concomitant lower limb revascularization angioplasty for chronic limb threatening ischaemia. The mean size of the foot ulcer at baseline was 11.3 ± 14.8 cm 2 and mean transcutaneous oxygen measurement value was 34.1 (±19.6) mm Hg. Wound closure of >75% was observed in 14/20 (70.0%) patients. There was a 91.3% (±14.9%) wound area reduction by 3 months (P = .001) and mean time for 100% closure was 77.6 ± 32.5 days. Mean pain scores reduced from 2.4 (±1.8) at baseline to .5 (±1.0) at 3 months (P = .008). All patients were very satisfied using the ambulatory device. Use of TOT in chronic diabetic foot wounds stimulates a healing state, underpinning the concept that oxygen plays a central role in wound healing. Our results are more compelling if you consider they started with relatively large-sized DFUs and majority of patients were frail with underlying peripheral artery disease. (NCT03863054)