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In vivo Tissue pO 2 Measurements in Hamster Skinfold by Recessed pO 2 Microelectrodes and Phosphorescence Quenching Are in Agreement
Author(s) -
BUERK DONALD G.,
TSAI AMY G.,
INTAGLIENTTA MACROS,
JOHNSON PAUL C.
Publication year - 1998
Publication title -
microcirculation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.793
H-Index - 83
eISSN - 1549-8719
pISSN - 1073-9688
DOI - 10.1111/j.1549-8719.1998.tb00071.x
Subject(s) - microelectrode , quenching (fluorescence) , phosphorescence , in vivo , chemistry , hamster , materials science , analytical chemistry (journal) , physics , optics , fluorescence , medicine , chromatography , biology , electrode , microbiology and biotechnology
Objective : Phosphorescence quenching has been used successfully to optically measure in vivo blood pO 2 in the microvasculature. Optical measurements have also been made in some tissues, but it is not clear whether these results accurately reflect tissue pO 2 . Methods : Recessed pO 2 microelectrodes and the phosphorescence quenching technique were used simultaneously to measure in vivo tissue pO 2 in hamster skinfold. The optical window for phosphorescence quenching was focused around the tips of microelectrodes that were positioned in tissue regions at least 100 µm from large microvessels. Results : Mean tissue pO 2 measured by recessed pO 2 microelectrodes was 18.4 ± 1.7 (SE) Torr, and mean tissue pO 2 determined from the time course of phosphorescence decay was 18.8 ± 2.0 Torr (no significant difference). The two tissue pO 2 measurements agreed over a wide range, from 2 to 46 Torr (r = 0.93, 39 paired measurements from six sites in 3 animals). There was no systematic change in the microelectrode tissue pO 2 during the period of light excitation used for the optical method. Conclusions : Under the conditions of our study, sufficient amounts of porphyrin dye leaked from the vasculature and diffused into tissue, allowing accurate measurements of tissue pO 2 by the phosphorescence quenching technique. Furthermore, the optical method did not deplete significant amounts of O 2 from tissue during light excitation.