Nitroglycerin- and Nicardipine-Induced Hypotension Does Not Affect Cerebral Oxygen Saturation and Postoperative Cognitive Function in Patients Undergoing Orthognathic Surgery

Purpose: The aim of this study was to investigate the influence of nitroglycerin- and nicardipine-induced hypotension on regional cerebral oxygen saturation (rSO₂) and postoperative cognitive function in patients undergoing orthognathic surgery. Patients and Methods: Sixty adult patients scheduled for orthognathic surgery were randomly assigned to either the nitroglycerin group (group 1) or nicardipine group (group 2). After induction of anesthesia, hypotension was induced with continuous infusion of nitroglycerin or nicardipine. Mean arterial pressure (MAP), heart rate (HR), and rSO₂ were measured at the following time points: before induction of anesthesia, immediately before commencing induced hypotension, at 30 and 60 minutes after induced hypotension, and immediately before the end of surgery. Cerebral desaturation was defined as a reduction of rSO₂ less than 75% of baseline for ≥15 seconds. The Mini Mental State Examination (MMSE) was conducted before surgery and then repeated after 1 week. Results: Baseline rSO₂ values were similar in the 2 groups. There were no significant differences in rSO₂ values between the 2 groups. Cerebral desaturation was not observed in any of the patients. Both nitroglycerin and nicardipine reduced MAP and increased HR during induced hypotension as compared with the baseline values (P < .05). No differences in MAP and HR during baseline and induced hypotension were observed between the 2 groups. Decreased MMSE scores were not observed in any of the patients. Conclusion: Cerebral oxygen saturation and postoperative cognitive function were not impaired during nitroglycerin- and nicardipine-induced hypotension in patients undergoing orthognathic surgery.