Post-operative cognitive functions after general anesthesia with sevoflurane and desflurane in South Asian elderly.
BACKGROUND
The duration of the recovery of cognition after anesthesia and surgery is multifactorial and is dependent on the type of anesthesia used, the type of surgery, and the patient. The present study compared the speed of recovery in elderly patients undergoing general anesthesia with sevoflurane or desflurane and the incidence and duration of cognitive impairment in them.


METHODS
The prospective study was conducted at a tertiary care centre in Bangalore from November 2008 to March 2010. Patients aged above 65 years with American Society of Anaesthesiology (ASA) physical status I, II, III undergoing surgeries under general anesthesia lasting from 45 min up to 3 hours were included in the study. The times from discontinuing nitrous oxide to eye opening, tracheal extubation, obeying commands, and the time to orientation to name and place were assessed at 30-60 s intervals. At 1, 3, 6 h after the end of anesthesia, the patient's cognitive functions were assessed by asking them to repeat the Mini Mental Score Examination.


STATISTICAL ANALYSIS USED
Student t-test, Chi-square test.


RESULTS
The time to eye opening, time until extubation, time to follow commands and orientation to time, place were significantly better with desflurane compared to sevoflurane (p < .001). Hundred percent of patients in the desflurane group and 97% in the sevoflurane group demonstrated completely normal cognitive function at 6 h postoperatively (p = 0.31).


CONCLUSION
Desflurane was associated with a faster early recovery than sevoflurane in elderly patients. However, postoperative recovery of cognitive function was similar with both volatile anaesthetics.