Physiological measurement
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Physiological measurement · May 1994
Comparative StudyComparison of macro- and micro-lightguide spectrophotometric measurements of microvascular haemoglobin oxygenation in the tuberculin reaction in normal human skin.
The changes in haemoglobin oxygenation (SO2) occurring in the tuberculin reaction in human skin were measured using macro- and micro-lightguide spectrophotometry and the results compared. A significant difference was found between the measurements from the respective instruments, demonstrating that the micro-lightguide technique measures only in the most superficial capillaries. Laser Doppler flux (LDF) and transcutaneous oxygen (tcpO2) measurements were also obtained concurrently. ⋯ Although SO2 was increased in the reaction, tcpO2 decreased. This suggests that the infiltrating cells may present a diffusion barrier to oxygen between the capillaries and the tissue cells. This study has shown that micro-lightguide spectrophotometry gives a local picture of intracapillary oxygen supply, which is useful in elucidating the pathophysiological changes occurring during chronic inflammation.