Laryngoscopyand endobronchial intubation usually cause transient hypertension and tachycardia. We investigated whether thoracic epidurally injected 3 µg/kg clonidine attenuates cardiovascular responses to intubation compared with 2 µg/kg fentanyl and 1 mg/kg lidocaine. Epidural catheterization was performed at the T6 -T7 or T7 -T8 intervertebral space, and saline or clonidine in saline was injected 20 min before anaesthetic induction. Anaesthesia was induced using 5 mg/kg thiopental sodium and 0.1 mg/kg vecuronium. Laryngoscopy and endobronchial intubation were performed 2 min later. Mean blood pressure and heart rate were measured throughout anaesthetic induction. In the control group and the fentanyl group, mean blood pressure and heart rate 3 min after endobronchial intubation were elevated significantly compared with baseline. In the clonidine group, however, mean blood pressure and heart rate did not increase compared with baseline. The control group had higher mean blood pressure and heart rate than the clonidine group 3 min after endobronchial intubation. Thoracic epidural clonidine may attenuate the haemodynamic response to endobronchial intubation.

This study compared the ability of the Zeus ® multifunctional anaesthesia system to control haemodynamic response to surgical stimulation in semi-closed (SCA) or closed circuit anaesthesia (CCA) modes. Fifty patients undergoing gynaecological surgery were randomly assigned to SCA or CCA. Anaesthesia was induced with 2 mg propofol and 0.9 mg/kg rocuronium, intravenously, and maintained using sevoflurane (minimum alveolar concentration [MAC], 1.0) using 2 l/min oxygen plus 2 l/min nitrous oxide (SCA 4 l/min group) or 50% oxygen plus 50% nitrous oxide (CCA group). An increase in mean arterial pressure (MAP) > 20% above baseline in response to surgical stimulation provoked a stepwise increase in sevoflurane (1.3 MAC and then 1.6 MAC), followed by fentanyl 1 µg/kg intravenously (rescue drug). The time required for MAP to return to within 10% of baseline was significantly shorter in the CCA group (6.4 ± 3.6 min) compared with the SCA 4 l/min group (10.2 ± 6.0 min). The percentage of patients requiring fentanyl was significantly greater in the SCA 4 l/min group than in the CCA group. In conclusion, CCA controlled acute haemodynamic responses to surgical stimuli more successfully and rapidly than SCA 4 l/min, using a multifunctional anaesthesia machine.