Effects of bispectral index monitoring on isoflurane consumption and recovery profiles for anesthesia in an elderly asian population

Background: Age related limited physiological reserves and associated co-morbidities in elderly patients require careful titration of inhalational anesthetic agents to minimize their side effects. The use of Bispectral index (BIS) monitoring may be helpful in this regard. The objectives of this study were to evaluate the effect of BIS monitoring on Isoflurane consumption during maintenance and recovery profile at the end of anesthesia. This Quasi experimental study was conducted for a 1 year period at the main operating units of a tertiary care hospital. Materials and Methods: Total 60 patients of age 60 years and above were enrolled in either standard practice (SP) or (BIS) group. In the SP group, the anesthesia depth was maintained as a routine clinical practice, while in BIS group it was maintained by monitoring the BIS score between 45 and 55. Standard anesthesia care was provided to all of the patients. Data including demographics, isoflurane consumption, hemodynamic variables and recovery profiles were recorded in both groups. Results: The mean isoflurane consumption was lower (P = 0.001) in the BIS group. The time to eye opening, extubation and ready to shift was shorter (P = 0.0001) in BIS group. The patients in BIS group had higher Post anesthesia recovery score ( P = 0.0001) than the SP group. Conclusion: The use of BIS in an elderly Asian population resulted in 40% reduction of isoflurane usage. The patients having BIS monitoring awoke earlier and had better recovery profiles at the end of anesthesia.