Noninvasive assessment of cerebral oxygenation during acclimation to hypobaric hypoxia

Factors regulating cerebral tissue Po-2 (PtO2) are complex. With the increa sed use of clinical PtO2 monitors, it has become important to elucidate the se mechanisms. The authors are investigating a new methodology (electron pa ramagnetic resonance oximetry) for use in monitoring cerebral PtO2 in awake animals over time courses of weeks. The authors used this to study cerebra l PtO2 in rats during chronic acclimation to hypoxia predicting that such a cclimation would cause an increase in PtO2 because of increases that occur in capillary density and oxygen carrying capacity. The average PtO2 between 7 and 21 days was increased by 228% over controls.