Effects Of Different Target Concentrations Of Remifentanil On Tracheal Extubation In General Anesthesia Patients

ObjectiveTo explore the effect and safety of different target concentration of remifentanil on tracheal extubation during emergence from general anaesthesia through the target controlled infusion (TCI), on basis of hemodynamics, stress hormone and adverse reaction of extubation.MethodsThis study was approved by the institutional review board of Yangzhou No.1 People’s Hospital, written informed consent was obtained from all patients. Sixty patients (ASA I or II grade) aged 18 to 60 years, scheduled for the day’s first elective nasal endoscopic surgery (nasal polyp, nasal septum and paranasal sinuses operation) were randomly allocated into four groups:the target concentration of remifentanil were pumpd to 0(group C),1.4(group R1), 1.7(group R2),2.0(group R3) ng/ml respectively during the extubation period.After fasting and drinking for 8 hours, all patients were premedicated with phenobarbital 0.1g and atropine 0.5mg intramuscularly 30 min before anesthesia induction. Patients were monitored with ECG, HR, SpO2 and non-invasive blood pressure (BP), the HR and BP were measured three times in 15 min, and the mean was referred to as their baseline values. All patients were infused with Ringer’s solution 4ml/kg in 15min, and maintained the infusion at 2ml·kg-1·h-1. Meanwhile, the venipuncture of another arm was reserved for blood samples. General anaesthesia was induced with IV dexamethasone 10mg, midazolam 0.05mg/kg, fentanyl 4μg/kg, propofol 2mg/kg, cisatracurium 0.15mg/kg before tracheal intubation, the cuff was inflated with air and the cuff pressure maintained at 20cmH2O, the ventilation tidal volume was 6-8ml/kg, respiratory rate was 12-16 bpm, endexpiratory carbon dioxide concentration maintained at 35-45mmHg. Anaesthesia was maintained with propofol 6mg·kg-1·h-1, cisatracurium 0.1mg·kg-1·h-1 and plasma TCI (Minto model) of remifentanil at 0.5-3.Ong/ml. After loss of consciousness, the neuromuscular monitoring was used during the operation. Through the adjustment of target concentration of remifentanil and use of drugs, such as ephedrine and atropine, the BP and HR were maintained within 20% of baseline values, mean arterial pressure (MAP) was maintained above 60mmHg. Cisatracurium was stopped 20 min before the end of surgery, propofol was stopped in nasalpacking, and meanwhile the remifentanil infusion was adjusted according to group assignment. In the control group the remifentanil was stopped, and the target concentration was reduced to 1.4ng/ml、1.7ng/ml and 2.0ng/ml respectively in groups R1,R2and R3. In the end of nasalpacking, neostigmine 0.02mg/kg and atropine 0.01 mg/kg were used to antagonize neuromuscular block, suction catheter was used to clear the secretions in the airways. When the TOF ratio≥ 80%, respiratory pattern changed to manual ventilation. When reach the indication, tracheal extubation was performed, remifentanil was stopped in group R1, R2 and R3 at the same time.SBP、DBP、MAP、HR、Sp02 and RR were recorded at 5 min after entering operation room(T0), nasalpacking(T1), at the time of extubation (T2), and at 1 min (T3),3 min (T4),and 5 min (T5),10min (T6),30 min (T7) after extubation, the plasma concentrations of cortisol(Cor), blood glucose(BG), lactic acid(Lac) were detected at T0,T1,T5 and T7, extubation time, respiratory depression, throat pain, extubation memory and cough score were recorded after tracheal extubation.Results1.Change of MAP and HR:At T2、T3、T4、T5, the MAP and HR in groups R1,R2 and R3 were significantly lower than that in group C (P<0.05); at T3 and T4, the MAP and HR in groups R2 and R3 were significantly lower than that in group C and R1 (P<0.05)2.Change of Cor、DA、E、NE、BG、Lac:2.1 Intragroup comparison:2.1.1 In groups C, the Cor at T5 and T7 were significantly higher than that at To (P<0.05).In groups R2 and R3, the Cor at T5 and T7 were significantly lower than that at To (P<0.05)2.1.2 In group C, the DA at T5 and T7 were significantly higher than that at To(P<0.05). In group R3, the DA at T5 and T7 were significantly lower than that at To (P<0.05)2.1.3 In group C, the E and NE at T1,T5 and T7 were significantly higher than that at To(P<0.05). Compared with the E and NE at To respectively, the figures in groups R1,R2 and R3 at T1, in groups R2 and R3 at T5 and in group R3 at T7 were significantly lower (P<0.05); the E and NE in group R1 at T5 and T7, in group R2 at T7 were significantly higher than that at T1 correspondingly (P<0.05); in group R2,the E and NE at T7 were significantly higher than that at T5.2.1.4 In each group, the BG and Lac had no significant difference at every time point (P>0.05).2.2 Intergroup comparison:2.2.1 At T5 and T7, the Cor in group C were significantly higher than that in groups R1,R2 and R3 (P<0.05)2.2.2 At T5 and T7, the DA in group R3 were significantly lower than that in group C, R1 and R2.2.2.3 Compared with the E and NE in group C respectively, the figures in groups R1,R2 and R3 at T1, in groups R2 and R3 at T5 and in group R3 at T7 were significantly lower (P<0.05); in group R3, the E and NE at T1, T5 and T7 were significantly lower than that in group R1 (P<0.05),meanwhile, the figures at T7 were significantly lower than that in group R2 (P<0.05).2.2.4 At every time point, the BG and Lac had no significant difference among all groups (P>0.05)3. Change of side effect after tracheal extubation:3.1 Extubation time:The time in groups R3 were significantly longer than that in groups C (P<0.05), R1 and R2, and there was no significant difference between groups R1 and R2 (P>0.05)3.2 Cough scores:Compared with group C, the figures were significantly higher in groups R1,R2 and R3 (P<0.05). Moreover, the scores were significantly higher in groups R1 than that in group R3 (P<0.05), and there was no significant difference between groups R1 and R2 (P>0.05)3.3 Grade of throat pain:The patients in group C felt significantly more pain than who in groups R1,R2 and R3 (P<0.05)3.4 Respiratory depression after extubation:Compared with group C, the incidence of respiratory depression was significantly higher in groups R1,R2 and R3 (P<0.05), and the incidence was significantly higher in group R3 than that in groups R1 and R2 (P<0.05)3.5 Extubation memory:The incidence of extubation memory was significantly lower in groups R1, R2 and R3 than that in group C (P<0.05)ConclusionsRemifentanil TCI could relieve the reaction of tracheal extubation in the nasal endoscopic surgery patients with general anaesthesia effectively,and the appropriate target concentration is 1.7ng/ml.