Effect Of Remifentanil And Midazolam On The Cardiovascular Response And Changes Of BIS During Induction

Objective: Larynogoscopy and orotracheal intubation areassociated with hemodynamic responses. The resultingtachycardia and hypertension may be associated with anincrease in morbidity and mortality in some patients.　Remifentanil is a new, ultra-short-acting, selective μ-receptoragonist that is structurally uniqe. Speed of onset of effect israpid(1～2min) but remifentanil is rapidly metabolized bynonspecific tissue and plasma esterase. Therefore, remifentanilmay be appropriate for attenuation of the pressor responses tobrief but noxious stimuli. The aim of this study was to assess theeffect of remifentanil and midazolam on changes incardiovascular response and the excitability of cerebral cortexby monitoring hemodynamic parameters and BIS values. Methods: We studied 33 ASA Ⅰ ～ Ⅲ patientsundergoing elective esophageal carcinoma or lung cancer, aged45～66yr and weighed 48～78kg. All of them presentesnegative in Allen's test and neither of them suffered fromcardiopulmonary and endocrine diseases. Patients who werepremedicated with intramuscular atropine 0.5mg were randomlyassigned to one of two groups( 16 patients in group remifentanil, 4英 文 摘 要and 17 ones in group fentanly). Before induction radial arterywas cannulated for continuous monitoring of blood pressure andheart rate, ECG and SpO2 were also monitored continuously.BIS was recorded using the Aspect A-2000TM BISTM Monitor.Immediately after a bolus dose of 2μg/㎏ remifentanil was givenover 60s, midazolam 0.2mg/kg was administered. Fentanly2.5μg/㎏ was given two minutes before midazolam 0.2mg/kgwas administered. Succinylcholine was then given intravenouslyto facilitate intubations. All the tracheal intubation wereaccomplished within 30 seconds. Atracurium 0.3mg/kg wasgiven intravenously. Five minutes after intubation, anaesthesiawas maintained with 2-3℅ enflurane inhalation. Thereafter thelungs were mechanically ventilated using a Ohmeda 7900Ventilator (respiratory rate,14-16/min; tidal volume,8-10ml/kg;I:E,1:1.5; oxygen flow, 1.0L/min). Muscle relaxtion wasmaintained with atracurium. The means of three continuousvalues of SBP, DBP, MAP , HR and BIS were regarded asbaseline values(T0). Observations of heart rate(HR), systolicblood pressure(SBP), diastolic blood pressure(DBP) and BISwere recorded every minute from the start of induction to 5 minafter inbution(T1 ,T2, T3 ,T4 ,T5, T6,T7,T8). The product of HRand SBP (RPP) was calculated. Blood samples were taken fromperipheral vein for the measurement of NE, E before induction,during intubation, and 2, 5 min after intubation. Results: Patient characteristics was similar for bothgroups. There were no differences in SBP, DBP, MAP , HR and 5英 文 摘 要BIS before induction of anaesthesia between the groups. Ingroup RF, SBP, DBP and MAP decreased in both groups afterinduction of anaesthesia (p＜0.05 or p＜0.01). SBP, DBP andMAP were significantly lower in the remifentanil group than inthe fentanly group 1 min before intubation (P<0.01). SBP, DBPand MAP increased significantly in the fentanly group afterlarynoscopy and tracheal intubation (P<0.01) and weresignificantly greater in the fentanly group than in theremifentanil group (P<0.01). HR decreased in the remifentanilgroup 1 min after induction (P<0.01), but increased in thefentanly group after larynoscopy and tracheal intubion (P<0.01).RPP was lower in the remifentanil group before intubation and 2min after intubation (P<0.01), but greater in the fentanly groupafter intubation and in the following 2 minutes (P<0.01). BISdecreased in both groups after induction of anaesthesia (P<0.01),but there were no significantly differences between theremifentanil group and the fentanly group. Remifentanilinhibited increase in NE during induction and intubation. E inboth groups decreased after induction. Conclusions1 We conclude that remifentan...