Comparison of the Effects of Dexmedetomidine and Remifentanil on Cognition State After Cataract Surgery

Dexmedetomidine is a potent and highly specific α2-adrenoreceptor agonist that induces sedative and analgesic effects over a short-term period. As a result of these benefits, dexmedetomidine may be a better alternative than other available drugs for keeping the patient’s cognition state in an acceptable condition after outpatient ophthalmic surgeries. This randomized study was conducted to compare the sedative effects of dexmedetomidine and remifentanil on the cognitive state of patients who have undergone cataract surgery. A total of 100 patients who were candidates for cataract surgery under local anesthesia received either dexmedetomidine (50 patients; D group) or remifentanil (50 patients; R group) in a double-blind, randomized study. The baseline cardiovascular status and mini mental state examination (MMSE) score for each patient were recorded. As a loading dose, dexmedetomidine (0.5 µg/kg) and remifentanil (0.1 µg/kg) were infused at 10 minutes and 5 minutes before topical anesthesia, respectively. Subsequently, the maintenance dose was administered at 0.2 µg/kg/hour and 0.05 µg/kg/minutes in the D and R groups, respectively. The surgical procedure was begun when the bispectral index (BIS) reached 70 - 80. MMSE test was done at a postanesthetic care unit (PACU) 120 minutes after the discontinuation of the drug. There was no statistically significant difference between the MMSE scores of the two groups before surgery (P = 0.6), but the MMSE test conducted at the PACU revealed significantly better cognitive outcomes in the D group than in the R group in patients younger and older than 65 years (P = 0.03 and P = 0.0001, respectively). This study revealed that dexmedetomidine may be a suitable agent for sedation in cataract surgery because it results in a more favorable postoperative cognitive status than remifentanil. Likewise, dexmedetomidine had no significant adverse effects on cardiovascular or respiratory systems.