Ishida K, et al. - Researchers sought to analyze the cerebrovascular CO₂ reactivity (CO₂R) in chronic renal failure (CRF) patients without diabetes mellitus (DM), uncontrolled hypertension, peripheral vascular disease, or neurological disease under isoflurane-nitrous oxide anesthesia. CO₂R in CRF patients did not exhibit any prominent variation from that in controls. In CRF patients with high blood urea nitrogen (BUN) concentrations, CO₂R could, however, be impaired, thereby reducing the cerebrovascular reserve capacity. As a result of DM serving as a major cause of CRF and the exclusion of DM patients, the yielded data could not be applicable to patients with DM-induced CRF.