Effects of target controlled infusion of remifentanil during emergence on the recovery profiles of tracheal extubation from anaesthesia

Abstract

Objective The trial was designed to examine the effects of target controlled infusion of remifentanil on recovery profiles such as cardiovascular responses and coughing after anaesthesia for thyroidectomy.Methods Eighty ASA Ⅰ or Ⅱ patients undergoing thyroidectomy surgery were randomly assigned to RF0.0 group,RF1.5 group,RF2.0 group,RF2.5 group.Each group contained 20 subjects.General anesthesia was maintained by total intravenous anesthesia (propofol and remifentanil).The target plasma concentrations of remifentanil were 0(RF0.0 group),1.5(RF1.5 group),2.0 (RF2.0 group),and 2.5 μg/L (RF2.5 group) during emergence from anesthesia.At the end of surgery,propofol was ceased.The infusion of remifentanil was stopped in RF0.0 group while maintained in the other 3 groups at a target plasma concentration of 1.5,2.0 μg/L or 2.5 μg/L till extubation.Heart rate (HR),mean arterial pressure (MAP),incidence and severity of coughing were recorded.Results The incidence and severity of coughing were lower in RF2.5 group and RF2.0 group compared with RF0.0 group(P＜0.05).MAP[(95±4),(87±4) mm Hg and(82±4) mm Hg (1 mm Hg=0.133 kPa)] and HR [(96.1±3.4),(85.2±3.0) and (79.9±2.4) bpm] values were significantly lower in the 3 groups rather than in RF0.0 group [MAP,(100±5) mm Hg and HR,(105±4) bpm] at the moment of tracheal extubation(P＜0.05).MAP [(100±3),(90±4) mm Hg and (86±4) mm Hg] and HR [(103±3),(92±3) bpm and (84±3) bpm] values were significantly lower in the 3 groups compared with the RF0.0 group [(100±5) mm Hg and(105±4) mm Hg] at 1 min after tracheal extubation(P＜0.05).MAP [(82.4±4.3) mm Hg and (85.7±4.0) mm Hg] and HR [(79.9±2.4) bpm and (84.4±3.3) bpm] values were significantly lower in RF2.5 group compared with RF1.5 group[(95±4) mm Hg and (100±3) mm Hg][(96.1±3.4) bpm and (103±3) bpm] or RF2.0 group [(87±4) mm Hg and (90±4) mm Hg] [(85.2±3.0) bpm and (92±3) bpm] at the moment or 1 min after tracheal extubation (P＜0.05).But time to eye opening and extubation were prolonged in RF2.5 group [(8.3±0.5) min and (11.6±0.7) min] compared with the RF0.0 group[(8.0±0.6) min and (9.8±0.5) min](P＜0.05).Conclusions Maintaining a remifentanil plasma concentration by TCI may reduce haemodynamic changes and incidence of coughing which associated with tracheal extubation in patients undergoing thyroidectomy.However,awakening may be delayed due to the relative higher remifentanil dose. Key words: Remifentanil; Target-controlled infusion; Tracheal extubation; Total intravenous anesthesia