Objective To observe the effect of sevoflurane and target controlled infusion (TCI)propofol on the oculocardiac reflex (OCR) in patients with paediatrie strabismus surgery.Methods One hundred and thirty-eight patients ASA Ⅰ-Ⅱ undergoing strabismus surgery were randomly allocated to six greups(propofol groups:P_1,P_2,P_3 group; sevoflurane groups:S_1,S_2,S_3 group,23 cases for each) according to target bispectral index (BIS) of 60,50 and 40.In propofol groups continuous infusion of propofolremifentanil [0.2μg/(kg·min)] was adjusted towards target BIS value.The sevoflurane-remffentanil [0.2μg/(kg·min) ] concentration with 50% N2O/O2 was adjusted toward target BIS too.The incidence of OCR and the lowest heart rate(HR) and BIS were recorded.Results The incidence of OCR were 73.9%(17/23),39.1%(9/23),17.4%(4/23),56.5%(13/23),26.1%(6/23),8.7%(2/23)in P_1,P_2,P_3,S_1,S_2,S_3 soup,P_2 and P_3 group were lower than P_1 group,S_2 and S_3 soup were lower than S_1 group,P_3,S_3,S_2,P_2 group were lower than S_1 and P_1 soup,S_1 soup was lower than P_1 group,S_2 soup was lower than P_2 group,S_3 group was lower than P_3 group,there was significant difference(P < 0.05 ).The densities of TCI propofol in P_2 and P_3 soup were higher than that in P_1 group [ (4.3 ±0.2),(5.5±0.1 ) mg/L vs (3.2±0.1 ) mg/L ] (P <0.05),and the densities of sevoflurane in S_2 and S_3 group were higher than that in S_1 group [ ( 1.8±0.3 )%,(2.3±0.2 )% vs(1.3±0.2 )% ] (P<0.05 ).The end-tidal concentration was different with difference of BIS too.Conclusions OCR is relevant to the depth of anesthesia.BIS values of 40-50 seem adequate for the inhibition of OCR.The results suggest that BIS may be a valuable tool during propofol-remifentanil or sevoflurane-remifentanil anesthesia for strabismus surgery in children.The incidence of OCR is higher in propofol than in sevoflurane at the same BIS.

Objective: To evaluate the role of extracellular signal-regulated kinase (ERK) signaling pathway in intrathecal dexmedetomidine-induced reduction of spinal cord ischemia-reperfusion (I/R) injury in rats. Methods: Eighty clean-grade male Sprague-Dawley rats, aged 9-10 weeks, weighing 300-350 g, were divided into 4 groups (n=20 each) using a random number table method: sham operation group (group S), spinal cord I/R group (group I/R), dexmedetomidine group (group D), and dexmedetomidine plus ERK signaling pathway blocker PD98059 group (group P). Spinal cord ischemia was produced by cross-clamping of the abdominal aorta distal to the left renal artery for 25 min followed by reperfusion to establish the model of spinal cord I/R injury.Dexmedetomidine 1 μg/kg was intrathecally injected at 20 min before establishing the model in D and P groups, PD98059 2 mg/kg was given via the tail vein at the same time in group P, and the equal volume of normal saline was given instead in S and I/R groups.Five rats were selected at 6, 8, 10 and 12 h of reperfusion, and the modified Basso, Beattie, Bresnahan (BBB) scale was used to assess the hindlimb locomotor function.Five rats were sacrificed after assessing the locomotor function at 6 h of reperfusion, and the L_3-5 segments of the spinal cord were taken for determination of cell apoptosis (by TUNEL) and expression of phosphorylated ERK (p-ERK) (by Western blot). The apoptosis index was calculated. Results: Compared with group S, the BBB scores were significantly decreased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was up-regulated in the other three groups (P<0.05). Compared with I/R group, the BBB scores were significantly increased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was up-regulated in group D, and no significant change was found in the apoptosis index or p-ERK expression in group P (P>0.05). Compared with group D, the BBB scores were significantly decreased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was down-regulated in group P (P<0.05). Conclusion The mechanism by which intrathecal dexmedetomidine reduces spinal cord I/R injury is related to activating ERK signaling pathway in rats.