TEWL, Closed-Chamber Methods: AquaFlux and VapoMeter
- 2.3k Downloads
TransEpidermal water loss (TEWL) is recognised as the main indicator of skin barrier function. Since the 1970s, the open-chamber method of measurement has established itself as the main method for TEWL measurement and a de facto standard against which newer technologies are judged. However, the open-chamber method is known to suffer from a number of limitations, the main one being disturbance by ambient air movements. This limitation can be overcome by closing the measurement chamber, but this design change affects other aspects of the measurement.
Closed-chamber instruments bring a new dimension to TEWL measurement, because their immunity to disturbance by external air movements makes it possible for such measurements to migrate away from the well-controlled laboratory environment into the workplace or clinic. This and other aspects of their design liberate them from many of the restrictions and precautions recommended in the now outdated TEWL guidelines.
This chapter describes two commercial closed-chamber instruments, the AquaFlux and the VapoMeter, whose characteristics are discussed within the context of the established open-chamber method. These instruments differ in measurement principle, concept and design. The AquaFlux, which uses the condenser-chamber method of measurement, is a benchtop, mains-powered instrument. The VapoMeter, which uses the unventilated-chamber method of measurement, is a self-contained, battery-powered instrument. Their performance characteristics are also quite different, with accuracy, sensitivity and repeatability the main features of the AquaFlux and speed and mobility the main features of the VapoMeter.
KeywordsMeasurement Chamber Water Vapour Flux Skin Barrier Function Sweat Gland Activity TEWL Measurement
We thank Markus Steiner of Aberdeen University, Scotland, for providing the raw Tewameter-VapoMeter comparison data used in Fig. 31.3 and Jouni Nuutinen of Delfin Technologies Ltd, Finland, for providing unpublished VapoMeter angular response data.
- 2.Imhof RE, Berg EP, Chilcott RP, Ciortea LI, Pascut FC (2002) New instrument for measuring water vapour flux density from arbitrary surfaces. IFSCC Mag 5(4):297–301Google Scholar
- 13.Angelova-Fischer I, Fischer TW, Zillikens D (2009) Die Kondensator-Kammer-Methode zur nicht-invasiven Beurteilung von irritativen Hautschäden und deren Regeneration: eine Pilotstudie. Derm Beruf Umwelt 57(3):125Google Scholar
- 15.Imhof RE, Xiao P, Berg EP, Ciortea LI (2005) Rapid measurement of TEWL with a condenser-chamber instrument. In: 15th international meeting of the ISBS and 2nd ioint international meeting of ISBS and ISSI, Philadelphia, 2005, pp 1–7. Available from: http://www.biox.biz/Library/Conference/ConfContribDetails10.php
- 18.Du Plessis J, Stefaniak A, Eloff F, John S, Agner T, Chou T-C et al (2013) International guidelines for the in vivo assessment of skin properties in non-clinical settings: part 2. Transepidermal water loss and skin hydration. Skin Res Technol 19(3):265–278Google Scholar
- 19.Barel AO, Clarys P (1995) Comparison of methods for measurement of transepidermal water loss. In: Serup J, Jemec GBE (eds) Handbook of non-invasive methods and the skin. CRC Press, Boca Raton, pp 179–184Google Scholar