The effects of general vs spinal anesthesia on frontal cerebral oxygen saturation in geriatric patients undergoing emergency surgical fixation of the neck of femur

Study Objective: To assess the effect of regional vs general anesthesia on transcranial cerebral oxygen saturation (rSo₂). Design: Prospective, randomized, open-label study. Setting: Large referral hospital. Patients: Sixty American Society of Anesthesiologists physical status I, II, and III geriatric patients at least 60 years of age, undergoing surgical fixation of the neck of femur. Interventions: Patients were randomized to receive either general (group GA) or spinal (group S) anesthesia. In all cases, frontal rSo₂ was measured for a 10-minute preoperative control period, throughout the surgical procedure, and for 10 minutes postoperatively. Measurement and Main Results: The frequency of a decrease in rSo₂ below baseline preoperative levels was significantly (P < .0001) higher in group S. However, the number of patients in whom at least one dip below baseline was recorded was similar between the groups. By contrast, general anesthesia was associated with a significantly higher rSo₂ when compared with spinal anesthesia. Logistic regression revealed no correlation between changes in blood pressure, heart rate, or peripheral oxygen saturation and the frequency of rSo₂ dips below baseline. Conclusion: Cerebral oxygen saturation is likely patient specific and independent of the anesthetic technique administered. Spinal anesthesia is associated with a higher incidence of cerebral desaturation. However, the number of patients in whom at least one dip below baseline was recorded was similar between the groups.