Comparison Of Dexmedetomidine, Remifentanil And Esmolol In Controlled Hypotensive Anaesthesia

摘要

We aimed at comparing dexmedetomidine, remifentanil, esmolol in controlled hypotension application during tympanoplasty for intraoperative bleeding, preoperative hemodynamics, recovery and adverse effects.70 patients, undergoing tympanoplasty operation, were included in the study. For hypotension, the target SAP was calculated as 40 % below the basal value. Group D (n=26) Dexmedetomidine 1 ?g kg-1 (10 min), 0.2-0.7 ?g kg-1h-1 Group R (n=21) Remifentanil 0.2-0.5 ?g kg-1min -1Group E (n=23) Esmolol 500 ?g kg-1(1 min), 50-300 ?g kg-1min -1 The same surgeon performed all the operations to ensure consistency in the estimation of the surgical field. Spontaneous eye open, extubation, verbal response, cooperation and orientation time were recorded. Groups did not differ in surgical area bleeding assessment scores. No statistically significant difference was found between postoperative recovery features. Dexmedetomidine, remifentanil and esmolol may be advisable used for controlled hypotension during tympanoplasty in respect of intraoperative bleeding, recovery and adverse effects. Introduction Controlled hypotension involves reducing arterial blood pressure 40-50 % below its normal range or reducing mean arterial pressure to 60 mmHg intentionally and recoverably and maintaining it at this level throughout the operation process (1). Controlled hypotension is intended for reducing blood loss, thereby minimising blood transfusion requirement. Surgeries during which controlled hypotension is preferred are mostly brain surgery, ear nose and throat, orthopaedics and plastic surgery. Middle ear surgeries involve utilisation of a microscope in a small area. During these surgeries, a slightest bleeding at the surgical area would look larger due to the magnifying effect of the microscope, which could upset the surgical comfort. Controlled hypotension is employed to provide an bloodless, readily visible surgical area in middle ear surgeries (2, 3).There is a variety of methods and medications administered for controlled hypotension. The ideal medication for controlled hypotension should be non-toxic, maintain cerebrovascular auto-regulation, not change cardiac performance, have short-term effect and be easily titrated (4,5).With this study we aimed at comparing dexmedetomidine, remifentanil and esmolol in controlled hypotension application during tympanoplasty operations for intraoperative bleeding, preoperative hemodynamics, recovery and adverse effects. Methods 70 ASA I-II patients, aged between 18-60, undergoing tympanoplasty operation, were included in the study upon consent of the hospital's ethical committee (Ref. No: 06-15) and written consents of the patients. Patients with dysrhythmia and with arterial pressure of 60 mmHg or lower were not included in the study. As a premedication 10 mg Diazepam (IM) was administered 30 minutes preoperatively. After written consents of the patients were taken, they were randomised through computer-generated method and taken in the operating room. Although 70 patients were randomised, 10 were excluded from the study. Electrocardiography and peripheral oxygen saturation (SPO2) monitoring was performed, and peripheral vascular access was obtained. Through Allen test and local anaesthesia administered at the area, invasive arterial monitoring was achieved through right arteria radials cannulation. Basal blood gas sample was collected. Basal systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP) and heart rate (HR) values were recorded. For hypotension, the target SAP was calculated as 40 % below the basal value. In attaining the target SAP, MAP value of 60 mmHg was taken as the threshold value. In anaesthetic induction to patients, fentanyl 1 μg kg -1 , propofol 2.5-3 mg kg -1 , vecuronium 0.1mg kg -1 was administered. Anaesthetic maintenance was ensured through 50 % O2-N2 O and 3-6 % desflurane. End-tidal CO2 (EtCO2) monitoring for the patients were performed with