Measuring hemoglobin oxygen saturation during graded hypoxic hypoxia in rat striatum

Cécile Julien, Adrian Bradu, Raphaël Sablong, Emmanuelle Grillon, Chantal Remy, Jacques Derouard, Jean François Payen

Research output: Contribution to journalArticlepeer-review

Abstract

We evaluated in vivo reflectance spectroscopy of visible light as a method to assess brain tissue hemoglobin oxygen saturation in rat striatum (SstrO 2). Seven anesthetized and mechanically ventilated rats were subjected to incremental reduction in the fraction of inspired oxygen (FIO 2): 0.35, 0.25, 0.15, 0.12, and 0.10, followed by a reoxygenation period (Group 1). At each episode, local changes in SstrO2 and in cerebral blood flow (LCBF) were simultaneously determined in the two striatal regions, using reflectance spectroscopy and laser Doppler flowmetry, respectively. Another group of rats (Group 2, n = 6) was also studied to measure sagittal sinus blood hemoglobin saturation (SssO2) during graded hypoxic hypoxia. Corpus striatum exhibited a significant graded decrease in SstrO2 from 38% ± 17% at FIO2 of 0.35 (control) to 16% ± 10% at FIO2 of 0.12 and to 13% ± 7% at FIO 2 of 0.10 (P < 0.05), with no difference between the two hemispheres. These local changes in SstrO2 were associated with a significant graded increase in LCBF: 161% ± 26% of control values and 197% ± 34% during these 2 hypoxic episodes, respectively (P < 0.05). All local changes were fully reversed during the reoxygenation period. In Group 2, SssO2 decreased from 38% ± 8% at FIO2 of 0.35 (control) to 10% ± 3% at FiO2 of 0.10, closely related to SstrO 2 decreasing in hypoxia. This study shows that reflectance spectroscopy of the visible light in rat striatum could be a possible measure of continuous changes in SstrO2. SssO2 and LCBF measurements during graded hypoxic hypoxia indicate that changes in SstrO2 reflect primarily those in brain venous oxygenation.

Original languageEnglish (US)
Pages (from-to)565-570
Number of pages6
JournalAnesthesia and analgesia
Volume102
Issue number2
DOIs
StatePublished - Feb 2006

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

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