Water-filtered infrared-A (wIRA) is a special form of heat radiation with high tissue penetration and a low thermal load to the skin surface, see Figure. wIRA promotes healing of acute and chronic wounds both by thermal and thermic as well as by non-thermal and non-thermic cellular effects. wIRA corresponds to the major part of the sun’s heat radiation, which reaches the surface of the Earth in moderate climatic zones filtered by water and water vapour of the atmosphere.
The results of 7 clinical studies (the largest study with 400 patients) about water-filtered infrared-A (wIRA) for wound healing have been published on 29.06.2016 as comprehensive review in the interdisciplinary e-journal "GMS German Medical Science" of the Association of Scientific Medical Societies (AWMF) .
The six included randomized controlled clinical trials compare a combination of high standard care plus wIRA treatment vs. high standard care alone.
wIRA increases tissue temperature (+2.7°C at a tissue depth of 2 cm), tissue oxygen partial pressure (+32% at a tissue depth of 2 cm) and tissue perfusion.
wIRA promotes normal as well as disturbed wound healing: wIRA diminishes inflammation and exudation, wIRA promotes infection defense and regeneration, and wIRA alleviates pain. During 230 irradiations without any exception an alleviation of pain was observed with a substantially reduced need for analgesics (52–69% less in the three groups with wIRA compared to the three control groups without wIRA after major visceral surgery, nearly 60% less need for analgesics in chronic venous stasis ulcers).
Further effects are:
- Faster reduction of wound area (in severely burned children: 90% reduction of wound size after 9 vs. 13 days, after 9 days approx. 89% vs. approx. 49% reduction in wound area, complete wound closure of chronic venous stasis ulcers after 14 vs. 42 days).
- Better overall evaluation of wound healing.
- Better overall evaluation of the effect of irradiation.
- Better cosmetic result.
- Lower wound infection rate (single preoperative irradiation: 5% vs. 12% wound infections in total, of these: late wound infections (postoperative days 9-30) 1.7% vs. 7.7%).
- Shorter hospital stay (discharge after 9 vs. 11 postoperative days).
The effects of wIRA are compiled with extensive numerical data in a table of several
pages and illustrated with figures.
Water-filtered infrared-A is a useful complement for the treatment of acute and chronic wounds.
Publication (freely available):
 Hoffmann G, Hartel M, Mercer JB. Heat for wounds – water-filtered infrared-A (wIRA) for wound healing – a review. GMS Ger Med Sci. 2016;14:Doc08.
DOI: 10.3205/000235, URN: urn:nbn:de:0183-0002352
Publication online freely available as PDF and shtml from:
Extensive presentation of a variety of applications of water-filtered infrared-A (including applications besides wound healing) in German language is freely available from:
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