The relationship between lowest bispectral index value and age in high spinal anesthesia

Abstract

The aim of this study was to quantify the sedative effects of high spinal anesthesia, according to patient age, by also evaluating respiratory and hemodynamic changes. A prospective study was performed in 60 patients who were electively scheduled for lower limb or lower abdominal surgery. They were allocated into one of 2 groups according to their age: older age (51-80 years) and young age (20-50 years). In all groups, the lowest intraoperative bispectral index (BIS) values significantly lower than preoperative values. Patients in the older age group had significantly lower intraoperative BIS values than younger patients. The sedative effect of high spinal anesthesia is greater in older patients than in young patients, with an increase in respiratory instability. Our study showed a negative correlation between age and lowest BIS value; the lowest BIS value was reduced in older patients.