[Correlation between the Narcotrend index, the cerebral state index and the predicted effect site concentration during different state of consciousness in elderly patients with target controlled infusion of propofol].

OBJECTIVE: To study the correlation between the Narcotrend index, cerebral state index and predicted effect site concentration during different state of consciousness in the absence of surgery in elderly patients with target controlled infusion of propofol. METHODS: Twenty patients aged from 65-75 years categorized as ASA class I - II who were scheduled to undergo general surgery under general anesthesia with target controlled infusion of propofol were recruited. During the target controlled infusion of propofol, the propofol infusion was set at an initial effect site concentration of 0.5 mg/L and increased by 0.5 mg /L every 5 min until the modified observer's assessment of alertness / sedation scale (OAA/S) values of zero. The predicted effect site concentration of propofol, the values of CSI and NCT were recorded and the sedation level was examined by the modified OAA/S every 20 s. The predicted effect site concentrations of propofol in target controlled infusion (TCI) system were recorded when they increased by more than 0.1 mg/L. The predicted effect site concentrations of propofol and the values of NCT and CSI at LVC and LOC of the patients were recorded. RESULTS: There was a good linear correlation between NCT and the predicted effect site concentration of propofol (R2 = 0. 867, P < 0.01), as well as that between CSI and the predicted effect site concentration of propofol (R2 = 0.893, P < 0.01). The predicted effect site concentrations of propofol at LVC was (1.56 +/- 0.13) mg/L while the values of NCT was 74.00 +/- 4.69 and CSI 69.82 +/- 5.47. The predicted effect site concentrations of propofol at LOC was (2.15 +/- 0.27) mg/L while the values of NCT and CSI were 63.30 +/- 7.50 and 58.78 +/- 6.90 respectively. All of the values of NCT, CSI and the predicted effect site concentrations had a good linear correlation with OAA/S. There was a negative correlation between OAA/S and the predicted effect site concentration. At the same time, there was a positive correlation between OAA/S and NCT as well as that between OAA/S and CSI. And the correlation coefficients were - 0.968, 0.938, 0.940 respectively (P < 0.01). The values of NCT were higher significantly than that of CSI in different degree of LOC (P < 0.01). CONCLUSION: During elder people's target controlled infusion of propofol, LVC and LOC occur within a definite range of predicted effect site concentrations. There is a good linear correlation between NCT, CSI and the predicted effect site concentrations of propofol. For the elders, both NCT and CSI reflect the sedation level of propofol. Although there is a significant correlation between NCT and CSI, a deviation does exist in a certain range. Therefore a simple 1:1 transfer from NCT to CSI is inadequate.

[Clinical research of hyperbaric, isobaric, and hypobaric solutions of bupivacaine in continuous spinal anesthesia].

OBJECTIVE: To compare the anesthesia properities of hyperbaric bupivacaine with those of isobaric and hypobaric solutions when administered in the supine position undergoing hip surgery or lower limb surgery using continuous spinal anesthesia. METHODS: Sixty patients( ASA I approximately III ) scheduled for hip or lower limb surgery were randomly divided into 3 groups with 20 patients in each group: Group A: 0. 375% hyperbaric bupivacaine solutions; Group B :0.375% isobaric bupivacaine solutions; and Group C: 0. 375% hypobaric bupivacaine solutions. The following variables were measured every 2 minutes during the first 30 minutes after the intrathecal injection : the onset time of sensation block, the highest plane of analgesia, the time to reach complete motor blockade, and the plane of analgesia and the extent of lower extremities' movement (modified bromage score, BMS) at different time after the administration. Meanwhile the changes of hemodynamics were recorded. RESULTS: There was no statistical difference among the basic conditions ( P > 0.05). The onset time of sensation block, and the time to reach complete motor blockade, and the time receiving the highest sharp pain sensory block in Group A were significantly shorter than those in Group B and Group C ( P < 0.01 ). The plane of analgesia obtained in the hyperbaric group was significantly higher than in both the isobaric and the hypobaric groups ( P < 0.01). The mean arterial pressure(MAP) , HR in the hyperbaric group decreased significantly after the intrathecal injection( P < 0.05 ). CONCLUSION: The 0.375% Isobaric bupivacaine used during contiuous spinal anesthesia in the supine position produces a suitable and a more "controllable" anesthesia, but a minimum dosage of 10 approximately 12.5 mg is required to obtain adequate anesthesic conditions with moderate hemodynamic changes and satisfying analgesia effects. Under similar conditions, 0. 375% hyperbaric bupivacaine produces major hemodynamic consequences with high cephalad spread and 0. 375% hypobaric bupivacaine has a too long onset time.

[Comparison of continuous spinal and combined spinal-epidural anesthesia in patients for uterectomy].

OBJECTIVE: To compare the anaesthetic effect and hemodynamic changes between the continuous spinal anaesthesia(CSA) and combined spinal-epidural anaesthesia (CSEA) in patients for uterectomy. METHODS: Sixty patients undergoing uterectomy were randomly divided into two groups: CSA group and CSEA group. Spinal anesthesia was performed at L2-3 interspace. An initial subarachnoid bolus of 0.5% hyperbaric bupivacaine 2 ml was injected in the CSA group; if analgesia did not reach T8, supplemental bupivacaine was injected by titrate incremental doses. In the CSEA group, epidural anesthesia was performed at T12-L1 with a catheter inserted into the epidural space for anesthesia maintenance, and then 0.5% hyperbaric bupivacaine 3 ml was injected to the subarachnoid at L2-3. The levels and times of sensory and motor block and hemodynamic changes were measured and analysed. RESULTS: The anesthetic dosage of the CSA group was smaller than that of the CSEA group (group P < 0.05). The times of sensory block to T8 or the maximal level and motor block were more rapid in the CSEA group than those of the CSA group (P < 0.05). Mean arterial pressure (MAP), which decreased significantly, was related with the baseline in the two groups; the time was 15 min and 25 min in the CSEA group and CSA group respectively (P < 0.05). There was no difference in the maximum decline of MAP in the two groups (P < 0.01). CONCLUSION: CSA is a safe technique of spinal anesthesia with small anesthetic dosages, more reliable and hemodynamically stable in patients for uterectomy.