Evaluation of the effects of controlled hypotension on cerebral oxygenation in tympanoplasty and tympanomastoidectomy surgery

Objective: In our study, it was aimed to evaluate the effects of controlled hypotension induced by Esmolol and Nicardipine on cerebral oxygenation, hemodynamics, intraoperative bleeding, surgical satisfaction and recovery characteristics in patients who had undergone tympanoplasty and tympanomastoidectomy surgery. Materials and Methods: Our study was planned as a prospective, randomized, controlled study in Çukurova University Faculty of Medicine (Ç.Ü.T.F) Department of Anesthesiology and Reanimation. After obtaining the approval of Ç.Ü.T.F Clinical Research Ethics Committee, 60 patients in the ASA I-II group, aged between 18-65 years, whose oral and written consent was obtained, who would undergo tympanoplasty and tympanomastoidectomy surgery under general anesthesia by the Ear Nose and Throat (ENT) Department were included in the study. Patients aged <18 years and >65 years, those with cerebrovascular disease (CVD), cardiovascular disease, congestive heart failure, peripheral artery disease, pulmonary, renal and hepatic disease, malignancy, drug allergy, and those who did not want to participate in the study were excluded from the study. The patients, whose PCR test was performed 2 days before the operation, together with the preoperative physical examination and laboratory evaluation, were taken to the waiting room. 5-7 ml/kg/hour 0.9% NaCl infusion was started in patients who underwent peripheral vein access with an 18 G IV cannula. Pre-induction electrocardiogram (ECG), non-invasive blood pressure, peripheral oxygen saturation (SpO2) and near-infrared spectrometry (NIRS) were monitored in the patients who were taken to the operating room. After the blood pressure and NIRS baseline values of the patients were recorded, anesthesia was induced with 2 mg/kg propofol, 0.6 mg/kg rocuronium and 0.5 µg/kg remifentanil. Anesthesia was maintained with 2% sevoflurane inhalation until intubation, 40% O2-60% air, 2% sevoflurane inhalation after intubation, 40% O2 - +60% N2O and 0.03 µcg/kg/min remifentanil infusion. Before the graft was placed in the surgical field, N2O was cut and ventilation was provided with 100% O2. The patients were divided into two groups at the 10th minute after induction using the randomization method mean arterial pressure measured with a goal of 30% less than basal value, Nicardipine infusion was started at 1 μg/kg/min in the N group and Esmolol infusion at 30 μg/kg/min in the E group. The maximum dose was planned to be 5 µg/kg/min for nicardipine and 300 µg/kg/min for Esmolol. In the intraoperative period, systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), end tidal carbon dioxide (EtCO2), SpO2, right and left cerebral NIRS values at 5-minute intervals until the end of the operation evaluated. Surgical satisfaction, maximum Nicardipine and Esmolol infusion dose, and possible intraoperative side effects were recorded. 2 mg/kg tramadol was administered for postoperative analgesia 30 minutes before the end of the operation. End of the operation, the extubation and recovery time of the patients, the length of stay in the PACU (postoperative recovery room), postoperative side effects (bradycardia, hypotension), antiemetic use, and additional analgesic requirement were recorded. Patients with an ALDRETE score >9 in PACU were sent to the ENT service. Results: There was no significant difference between the groups in the age, weight, gender, duration of anesthesia, duration of surgery, extubation time, compilation time, time to stay in the PACU, postoperative Aldrette recovery scores, and antiemetic use of the patients included in the study. In the nicardipine group, SAB at the 70th min (p=0.045), 15th and 75th min. On the other hand, DAB values were found to be higher than the Esmolol group (p=0.013 and p=0.021, respectively). In the nicardipine group, MAP was 15. min (p=0.024), 70. It was determined that the min (p=0.025) and 80th min (p=0.045) values were higher than the Esmolol group. HR in the nicardipine group was higher at the 15th, 25th, 30th, 35th and 40th minutes compared to the Esmolol group (p<0.05). SpO2 values were significantly higher in the nicardipine group at the 85th and 95th minutes compared to the Esmolol group (p<0.05). ETCO2 values were similar between the two groups except at the 10th and 85th minutes (p<0.05). Left NIRS values in the nicardipine group at 20. and 40. minutes, and right NIRS values at 25., 30., 35., 40., 45. and 60. minutes were higher than Esmolol group. (p<0.05). Mild surgical bleeding that did not or rarely required aspiration was detected in 23 patients in the Esmolol group and 11 patients in the Nicardipine group. Minor bleeding requiring frequent aspiration was observed in 7 patients in the Esmolol group and in 18 patients in the Nicardipine group, and severe bleeding requiring frequent aspiration was observed in 1 patient in the Nicardipine group. The rate of evaluation of surgical satisfaction as "good and very good" was higher in the Esmolol group than in the Nicardipine group (p<0.05). Conclusion: Esmolol can both be administered in controlled hypotension in sevoflurane-remifentanil anesthesia in tympanomastoid/tympanoplasties, cerebral oxygenation is maintained at the doses administered, desaturation is not observed, Esmolol causes less surgical bleeding and is superior to Nicardipine in terms of surgical satisfaction, Postoperative heart rate due to Esmolol ın the opinion that Nicardipine can be preferred in low cases. Keywords: Controlled hypotension, Esmolol, NIRS, Nicardipine, Tympanoplasty.