Noninvasive assessment of cerebral oxygenation during acclimation to hypobaric hypoxia

Abstract

Factors regulating cerebral tissue PO2 (P(t)O2) are complex. With the increased use of clinical P(t)O2 monitors, it has become important to elucidate these mechanisms. The authors are investigating a new methodology (electron paramagnetic resonance oximetry) for use in monitoring cerebral P(t)O2 in awake animals over time courses of weeks. The authors used this to study cerebral P(t)O2 in rats during chronic acclimation to hypoxia predicting that such acclimation would cause an increase in P(t)O2 because of increases that occur in capillary density and oxygen carrying capacity. The average P(t)O2 between 7 and 21 days was increased by 228% over controls.