Effect of different applications of remifentanil on the emergence from general anesthesia in patients undergoing neurosurgical procedures

Objective To evaluate the effect of different applications of remifentanil on cough response during emergence from general anesthesia in patients undergoing neurological procedures. Methods Sixty patients scheduled for neurological procedures (ASA Ⅰ - Ⅱ ) were performed the tracheal intubation by the way of fast induction,anesthesia was maintained with continuous infusion of propofol combined with remifentanil during the operation.At the end of operation,all patients were randomly assigned into three groups (n=20) by different applications of remifentanil:group A,B,C.Patients in group A were not infused remifentamil until incision was closed. Remifentanil infusion was stopped when the incision was totally closed,group B recived a bolus dose of remifentanil ( 1 μg/kg) again at bandaging the incision.Group C received the continuous infusion of remifentanil 0.05μg·kg-1·min-1 until extubation.heart rate (HR),mean arterial pressure (MAP) and oxygen saturation (SpO2),were recorded before extubation,extubation immediately,1 and 3 min after extubation,respectively.Operating time,recovery time,extubating time,the total consumption of propofol and remifentanil,and the degree of cough response were also observed.Results At the time point of extubation,HR was (101±7),(90±8) and (78±9) beats/min in group A,B and C,respectively,at 1 min after extubation,HR was (98t9),(83±6) and (80t5) beats/min in group A,B and C,respectively; at 3 min after extubation,HR was (93±5),(82±7)and (82±5) beats/min in group A,B,and C,respectively.HR was significantly lower in group B and C than in group A at all the time points(P＜0.05 ).At the time of extubation,MAP was (97±11 ),(87±9) and (77±7) mm Hg( 1 mm Hg =0.133 kPa) in groupA,B and C,respectively,at 1 min after extubation,MAP was (92±8), (84±8) and (75±6) mm Hg in group A,B and C,respectively; at 3 min after extubation,MAP was (85±6), (80±5) and (76±6) mm Hg in group A,B and C,respectively.Compared with group A,MAP siginificantly decreased at time of extubation and 1 minute after extubation in group B,also siginificantly decreased at three recorded time in group C (P＜0.05).HR and MAP at all recorded time after extubation had no significant difference compared with the time point before extubation in group C (P＞0.05).There was no significant difference in awake time,extubating time and OAA/S scores after extubation among three groups (P＞0.05).During extubation,there were 8 patients with slight cough and 12 patients with heavy cough in group A,7 patients slightly coughed and 13 patients with no cough in group B,only 4 patients slightly coughed in group C.The incidence and degree of cough were significantly lower in group B and C than in group A (P＜0.05). Conclusions Continuous infusion of remifentanil (0.05 μg·kg-1·min-1) until extubation or a bolus of remifentanil (1 μg/kg) may elevate patient's toleration of intubation,reduce their cough response,and inhibit their over-change of HR and MAP during extubation without affecting the recovery from anesthesia. Key words: Piper dines; The general anesthesia; Extubation; Neurosurgical procedures