Objective The aim of this study was to investigate if target-controlled-infusion of remifentanil as sole agent affect bispectal index(BIS) and auditory evoked potential index (AEPI).Methods Twenty two ASAⅠ-Ⅱpatients...Objective The aim of this study was to investigate if target-controlled-infusion of remifentanil as sole agent affect bispectal index(BIS) and auditory evoked potential index (AEPI).Methods Twenty two ASAⅠ-Ⅱpatients scheduled for elective surgery were enrolled in this study.A effect-site target-controlled infusion of remifentanil was started to increase concentration gradually , the initial remifentanil concentration was set at 2.0 ng·mL -1 and was increased by 1.0 ng·mL -1 until 8.0 ng·mL -1.At baseline and at each successive target concentration of remifentanil ,the BIS,AEPI ,observer’s assessment of alertness/sedation (OAA/S) ,hemodynamic variables and respiratory rate were recorded.Results Increasing predicted remifentanil effect-site concentration(CeREMI) decreased BIS value,compared with 0 ng·mL -1,the mean values of BIS were significantly reduced from 4.0 ng·mL -1(P<0.05).No significant difference in AEPI values were found.There was great variation existing in reaction to remifentanil in patients.BIS value decreased obviously in 9 patients(≤70)but in another 10 patients remained unchanged(≥90).In 9 remifentanil-sensitive patients,the spearman correlation coefficient of BIS mean value between CeREMI was -0.715 and between OAA/S was 0.705.However,in another10 remifentanil-insensitive patients,we had not found any correlation in BIS mean value between CeREMI or OAA/S. Conclusion We conclude that at the concentration used in clinical practice,great variation exists in patients’ reaction to remifentanil.Whether remifentanil affects BIS or not depend on if it produce sedative effect in patients.We have to consider the individual difference of BIS in remifentanil application.展开更多
Background There are few studies to assess whether the effect-site concentration of propofol can predict anesthetic depth during the target-controlled infusion （TCI） induction in elderly patients. This study aimed t...Background There are few studies to assess whether the effect-site concentration of propofol can predict anesthetic depth during the target-controlled infusion （TCI） induction in elderly patients. This study aimed to evaluate the relationship between effect-site concentration of propofol and depth of anesthesia during the TCI induction in elderly patients. Methods Ninety patients （60-80 years） with an American Society of Anesthesiologists （ASA） physical status of 1-3, undergoing scheduled abdominal and thoracic surgery under general anesthesia were randomly allocated into one of three groups, Group S1, S2 and S3 （30 patients in each group）. The patients in Group S1 received propofol with a target plasma concentration of 4.0 pg/ml; patients in Group S2 received propofol with an initial target plasma concentrations of 2.0 IJg/ml that was raised to 4.0 pg/ml 3 minutes later; patients in Group S3 received an infused scheme of 3 steps; starting from a target plasma concentration of 2.0 pg/ml that was increased stepwised by 1 pg/ml until a target plasma concentration of 4.0 pg/ml was achieved, the interval between the two steps was 3 minutes. When an Observer＇s Assessment of Alertness/Sedation （OANS） score of 1 was achieved, remifentanil （effect-site concentration （Ce） of 4.0 ng/ml） and rocuronium 0.9 mg/kg were administered. Tracheal intubation was started 2 minutes after rocuronium injection. Changes of propofol Ce, blood pressure （BP）, heart rate （HR）, and bispectral index （BIS） were recorded. Results When an OAA/S score of 1 was achieved, Ce of propofol were （1.7±0.4） pg/ml, （1.9±0.3） pg/ml, （1.9±0.4） pg/ml and the BIS values were 64±5, 65±8, and 62±8 in Groups S1, S2 and S3. Before intubation, Ce of propofol was （2.8±0.2） pg/ml, （2.8±0.3） pg/ml, （2.7±0.3） pg/ml, and the BIS values were 48±7, 51±7, and 47±5 in Groups S1, S2 and S3. By linear regression analysis, a significant correlation between Ce of propofol and BIS values was found （展开更多
The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the ...The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the adsorp- tion equilibration of MO on CS beads. An obvious Cs-effect was observed in the adsorption equilibration, i.e., the ad- sorption amount（F） was declined with Cs increase. The classical Langmuir model adequately described the adsorption isotherm for each given cs. However, it could not be used to predict the cs-effect observed. The applicability of the Langmuir-SCA isotherm, a surface component activity（SCA） model equation, to fit the cs-effect data was examined. In the SCA model, the activity coefficient of sorbent surface sites, fsH2O, was assumed to be a function of cs due to the deviation of a real adsorption system from an ideal one, arisen from sorbent particle-particle interactions in real systems. The results show that the Langmuir-SCA isotherm could accurately describe the c：effect observed under the studied conditions. Furthermore, the effects of temperature（t）, pH, and electrolyte（NaNO3） concentration（ CNaNO3 ） on fsH2O were examined. The results show that fsH2O clearly decreased with increasing t（20-35℃） and pH（5-8）, but no obvious change in fsH2O was observed as CNaNO3 varied in a range 0.001-0.010 mol/L. These results give a better understanding of the cs-effect.展开更多
文摘Objective The aim of this study was to investigate if target-controlled-infusion of remifentanil as sole agent affect bispectal index(BIS) and auditory evoked potential index (AEPI).Methods Twenty two ASAⅠ-Ⅱpatients scheduled for elective surgery were enrolled in this study.A effect-site target-controlled infusion of remifentanil was started to increase concentration gradually , the initial remifentanil concentration was set at 2.0 ng·mL -1 and was increased by 1.0 ng·mL -1 until 8.0 ng·mL -1.At baseline and at each successive target concentration of remifentanil ,the BIS,AEPI ,observer’s assessment of alertness/sedation (OAA/S) ,hemodynamic variables and respiratory rate were recorded.Results Increasing predicted remifentanil effect-site concentration(CeREMI) decreased BIS value,compared with 0 ng·mL -1,the mean values of BIS were significantly reduced from 4.0 ng·mL -1(P<0.05).No significant difference in AEPI values were found.There was great variation existing in reaction to remifentanil in patients.BIS value decreased obviously in 9 patients(≤70)but in another 10 patients remained unchanged(≥90).In 9 remifentanil-sensitive patients,the spearman correlation coefficient of BIS mean value between CeREMI was -0.715 and between OAA/S was 0.705.However,in another10 remifentanil-insensitive patients,we had not found any correlation in BIS mean value between CeREMI or OAA/S. Conclusion We conclude that at the concentration used in clinical practice,great variation exists in patients’ reaction to remifentanil.Whether remifentanil affects BIS or not depend on if it produce sedative effect in patients.We have to consider the individual difference of BIS in remifentanil application.
文摘Background There are few studies to assess whether the effect-site concentration of propofol can predict anesthetic depth during the target-controlled infusion （TCI） induction in elderly patients. This study aimed to evaluate the relationship between effect-site concentration of propofol and depth of anesthesia during the TCI induction in elderly patients. Methods Ninety patients （60-80 years） with an American Society of Anesthesiologists （ASA） physical status of 1-3, undergoing scheduled abdominal and thoracic surgery under general anesthesia were randomly allocated into one of three groups, Group S1, S2 and S3 （30 patients in each group）. The patients in Group S1 received propofol with a target plasma concentration of 4.0 pg/ml; patients in Group S2 received propofol with an initial target plasma concentrations of 2.0 IJg/ml that was raised to 4.0 pg/ml 3 minutes later; patients in Group S3 received an infused scheme of 3 steps; starting from a target plasma concentration of 2.0 pg/ml that was increased stepwised by 1 pg/ml until a target plasma concentration of 4.0 pg/ml was achieved, the interval between the two steps was 3 minutes. When an Observer＇s Assessment of Alertness/Sedation （OANS） score of 1 was achieved, remifentanil （effect-site concentration （Ce） of 4.0 ng/ml） and rocuronium 0.9 mg/kg were administered. Tracheal intubation was started 2 minutes after rocuronium injection. Changes of propofol Ce, blood pressure （BP）, heart rate （HR）, and bispectral index （BIS） were recorded. Results When an OAA/S score of 1 was achieved, Ce of propofol were （1.7±0.4） pg/ml, （1.9±0.3） pg/ml, （1.9±0.4） pg/ml and the BIS values were 64±5, 65±8, and 62±8 in Groups S1, S2 and S3. Before intubation, Ce of propofol was （2.8±0.2） pg/ml, （2.8±0.3） pg/ml, （2.7±0.3） pg/ml, and the BIS values were 48±7, 51±7, and 47±5 in Groups S1, S2 and S3. By linear regression analysis, a significant correlation between Ce of propofol and BIS values was found （
基金Supported by the National Natural Science Foundation of China（Nos.21173135, 51372141） and the Specialized Research Fund for the Doctoral Program of Higher Education of China（No.20110131130008）,
文摘The adsorption of methyl orange（MO） on chitosan（CS） beads in aqueous solutions was investigated by a batch equilibration technique. Special emphasis was focused on the effect of sorbent concentration（cs） on the adsorp- tion equilibration of MO on CS beads. An obvious Cs-effect was observed in the adsorption equilibration, i.e., the ad- sorption amount（F） was declined with Cs increase. The classical Langmuir model adequately described the adsorption isotherm for each given cs. However, it could not be used to predict the cs-effect observed. The applicability of the Langmuir-SCA isotherm, a surface component activity（SCA） model equation, to fit the cs-effect data was examined. In the SCA model, the activity coefficient of sorbent surface sites, fsH2O, was assumed to be a function of cs due to the deviation of a real adsorption system from an ideal one, arisen from sorbent particle-particle interactions in real systems. The results show that the Langmuir-SCA isotherm could accurately describe the c：effect observed under the studied conditions. Furthermore, the effects of temperature（t）, pH, and electrolyte（NaNO3） concentration（ CNaNO3 ） on fsH2O were examined. The results show that fsH2O clearly decreased with increasing t（20-35℃） and pH（5-8）, but no obvious change in fsH2O was observed as CNaNO3 varied in a range 0.001-0.010 mol/L. These results give a better understanding of the cs-effect.
