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Fig. 1 | Critical Care

Fig. 1

From: Non-invasive monitoring of mitochondrial oxygenation and respiration in critical illness using a novel technique

Fig. 1

a Principle of the PpIX-TSLT. The pathway by which topical ALA administration enhances mitochondrial PpIX levels and the principle of delayed fluorescence detection after an excitation pulse with green (510 nm) light. Emission light is the delayed fluorescence (red light, 630–700 nm) and its lifetime is oxygen dependent. b PpIX emits delayed fluorescence after excitation by a pulse of green (510 nm) light. The delayed fluorescence lifetime is oxygen dependent according to the Stern–Volmer equation (inset), in which kq is the quenching constant and τ0 is the lifetime at zero oxygen. ALA 5-aminolevulinic acid, CPIII coporporphyrinogen III, PBG porphobilinogen, PO2 oxygen tension, PpIX protoporphyrin IX, UPIII urporphyrinogen III

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Critical Care

ISSN: 1364-8535