Effect of Anesthetic Methods on Cerebral Oxygen Saturation in Elderly Surgical Patients: Prospective, Randomized, Observational Study

Abstract

Intraoperative cerebral oxygen desaturation was reported to be associated with postoperative cognitive dysfunction in elderly patients. The effect of the anesthesia method on regional cerebral oxygen saturation (rSO(2)) is still a question under debate. The purpose of this study was to compare the effects of three common anesthesia methods on intraoperative rSO(2) changes in elderly patients. In this prospective randomized clinical trial, 87 patients scheduled for elective transurethral prostatectomy were allocated to receive general inhalational anesthesia (GA group, n = 30), spinal anesthesia (SA group, n = 28), or spinal anesthesia plus sedation with midazolam (SA+S group, n = 29). The numbers of patients showing a decrease in rSO(2) below the baseline value were higher in the SA (92.9 %) and SA+S (100 %) groups than in the GA group (33.3 %). The number of patients with a ≥ 50 % decrease in rSO(2) below baseline was greater in the SA+S (31.0 %) group than in the GA (0 %) or SA (3.6 %) group. During surgery, patients subjected to general anesthesia had higher rSO(2) than those with spinal anesthesia. Blood pressures and heart rates were similar in three groups except 5 and 10 min after anesthesia. Intraoperative SpO(2) was higher in the GA group than in the two spinal anesthesia groups. Spinal anesthesia is associated with more frequent cerebral desaturation than general anesthesia; and it was aggravated when combined with midazolam sedation. The cerebral effects of anesthesia should be considered when managing high-risk elderly patients.