Effect of local anesthesia (with lidocaine vs bupivacaine) on cognitive function in patients undergoing elective cataract surgery.

Purpose: Postoperative cognitive dysfunction has gained much attention over the last years. Multiple clinical trials have attempted to differentiate the effect of local vs general anesthesia on postoperative cognitive function. The aim of this work was to study the effect of local anesthesia with lidocaine vs bupivacaine on cognitive function.

Patients and methods: This was a prospective randomized trial carried out on 61 patients undergoing elective cataract surgery by phacoemulsification under local anesthesia. Twenty-eight patients received lidocaine 2% and 33 patients received bupivacaine 0.5%. Cognitive assessment for all patients was done preoperatively and 1 week postoperatively using paired associate learning test (PALT) and category verbal fluency (VF) test (animal category).

Results: Regarding cognitive assessment of patients in lidocaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.004), and between the mean value of preoperative VF and postoperative VF (P-value =0.002). As for bupivacaine group, there was a statistically significant difference between the mean value of preoperative PALT and postoperative PALT (P-value =0.021), and between the mean value of preoperative VF and postoperative VF (P-value =0.037). On comparing lidocaine and bupivacaine groups in pre and postoperative PALT & VF scores, there was no statistically significant difference between both groups.

Conclusion: Both lidocaine and bupivacaine caused postoperative cognitive impairment. Lidocaine was found to have a worse effect on cognitive function than bupivacaine, but the difference was not statistically significant.