Effect of hypotensive anesthesia on cognitive functions. A comparison of esmolol and remifentanil during tympanoplasty

OBJECTIVE: To compare the effects of esmolol and remifentanil, used as adjuncts for induced hypotension on surgical conditions and short-term cognitive functions, during tympanoplasty.

METHODS: The study was conducted in Hacettepe University, School of Medicine, Ankara, Turkey between January 2005 and December 2006 following Institutional Ethical Committee approval, 40 ASA I-II patients, between 18 and 60 years of age were included in this study. With the induction of anesthesia, for group E, an esmolol infusion of 50-250 ug.kg-1.min-1 was titrated, following a bolus of 0.5 mg.kg-1; for group R, a remifentanil infusion of 0.2-0.5 ug.kg-1.min-1 was titrated; to achieve a mean blood pressure (BP) of 55-65 mm Hg. Arterial BP were recorded continuously throughout the operation. Mini Mental State Test (MMS) was performed at the preoperative 30th minute (MMSP), postoperative 30th minute (MMS30), 60th minute (MMS60) and 24th hour (MMS24). Surgical field was evaluated by the blinded surgeon, using a 6 point category scale.

RESULTS: Patient demographics were similar in both groups. Sustained controlled hypotension was sufficient in all of the groups throughout surgery. Surgical field scores were lower in group R (p<0.05), although the scores were </=2 in both groups, which was regarded as adequate for tympanoplasty. Four patients in group R (20%) and one patient in group E (5%) showed cognitive function decline between MMSP and MMS30. Within both groups, there were statistically significant differences between MMS60 and MMSP, MMS24 and MMSP, MMS60 and MMS30, MMS24 and MMS30, but the results were similar between the groups.

CONCLUSION: Remifentanil or esmolol provided adequate induced hypotension and similar operating conditions and their effects on cognitive functions in the short postoperative period are similar for tympanoplasty.