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Kristin Walters - One of the best experts on this subject based on the ideXlab platform.
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propofol blood concentration and the Bispectral Index predict suppression of learning during propofol epidural anesthesia in volunteers
Anesthesia & Analgesia, 1995Co-Authors: Kate Leslie, Daniel I. Sessler, Marc Schroeder, Kristin WaltersAbstract:Propofol is often used for sedation during regional anesthesia. We tested the hypothesis that propofol blood concentration, the Bispectral Index and the 95% spectral edge frequency predict suppression of learning during propofol/epidural anesthesia in volunteers. In addition, we tested the hypothesis that the Bispectral Index is linearly related to propofol blood concentration. Fourteen healthy, male volunteers were studied on three randomly ordered days: no propofol, target propofol blood concentration 1 microgram/mL, and target propofol blood concentration 2 micrograms/mL. Each day, epidural anesthesia (approximately T11 level) was induced using 2% 2-chloroprocaine. Propofol was infused by a computer-controlled pump, and propofol concentration measured in central venous blood. We administered a Trivial Pursuit-type question task on all 3 days. The electroencephalogram was monitored continuously (Fp1, Fp2; reference, Cz; ground, mastoid). Propofol caused concentration-related impairment of learning. The propofol blood concentration suppressing learning by 50% was 0.66 +/- 0.1 microgram/mL. The Bispectral Index value when learning was suppressed by 50% was 91 +/- 1. In contrast, the 95% spectral edge frequency did not correlate well with learning. The Bispectral Index decreased linearly as propofol blood concentration increased (Bispectral Index = -7.4.[propofol] + 90; r2 = 0.47, n = 278). There was no significant correlation between the 95% spectral edge frequency and propofol concentration. In order to suppress learning, propofol blood concentrations reported to produce amnesia may be targeted. Alternatively, the Bispectral Index may be used to predict anesthetic effect during propofol sedation.
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Propofol blood concentration and the Bispectral Index predict suppression of learning during propofol/epidural anesthesia in volunteers.
Anesthesia and analgesia, 1995Co-Authors: Kate Leslie, Daniel I. Sessler, Marc Schroeder, Kristin WaltersAbstract:Propofol is often used for sedation during regional anesthesia. We tested the hypothesis that propofol blood concentration, the Bispectral Index and the 95% spectral edge frequency predict suppression of learning during propofol/epidural anesthesia in volunteers. In addition, we tested the hypothesis that the Bispectral Index is linearly related to propofol blood concentration. Fourteen healthy, male volunteers were studied on three randomly ordered days: no propofol, target propofol blood concentration 1 microgram/mL, and target propofol blood concentration 2 micrograms/mL. Each day, epidural anesthesia (approximately T11 level) was induced using 2% 2-chloroprocaine. Propofol was infused by a computer-controlled pump, and propofol concentration measured in central venous blood. We administered a Trivial Pursuit-type question task on all 3 days. The electroencephalogram was monitored continuously (Fp1, Fp2; reference, Cz; ground, mastoid). Propofol caused concentration-related impairment of learning. The propofol blood concentration suppressing learning by 50% was 0.66 +/- 0.1 microgram/mL. The Bispectral Index value when learning was suppressed by 50% was 91 +/- 1. In contrast, the 95% spectral edge frequency did not correlate well with learning. The Bispectral Index decreased linearly as propofol blood concentration increased (Bispectral Index = -7.4.[propofol] + 90; r2 = 0.47, n = 278). There was no significant correlation between the 95% spectral edge frequency and propofol concentration. In order to suppress learning, propofol blood concentrations reported to produce amnesia may be targeted. Alternatively, the Bispectral Index may be used to predict anesthetic effect during propofol sedation.
I F Russell - One of the best experts on this subject based on the ideXlab platform.
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the ability of Bispectral Index to detect intra operative wakefulness during isoflurane air anaesthesia compared with the isolated forearm technique
Anaesthesia, 2013Co-Authors: I F RussellAbstract:: It has been suggested that monitoring during total intravenous anaesthesia should include aspects of brain function. The current study used a manually adjusted target-controlled infusion of propofol for anaesthesia, guided to a Bispectral Index range of 55-60. Intra-operative responsiveness, as assessed by the isolated forearm technique, was compared with whether the Bispectral Index predicted/identified a patient's appropriate hand movements in responses to commands. Twenty-two women underwent major gynaecological surgery with total intravenous anaesthesia, propofol, remifentanil and atracurium. Sixteen women responded, on 80 occasions, with appropriate hand movements to commands during surgery, of which the Bispectral Index detected 47 (sensitivity 59%). The Bispectral Index suggested consciousness 220 times in the absence of movement responses (specificity 85%). The positive predictive value of a Bispectral Index response was 18%. While two women had vague recall about squeezing fingers, none had recall of surgery. For patients who responded more than once during surgery the Bispectral Index value associated with a response was not constant. Although there was no difference in the median (IQR [range]) effect site propofol concentration between intra-operative responses (2.0 (1.5-2.3 [1.2-4.0]) μg.ml(-1)) and eye opening after surgery (2.1 (1.7-2.8 [1.5-3.9]) μg.ml(-1)), the median (IQR [range]) Bispectral Index value at eye opening after surgery was significantly higher than that associated with responses during surgery: 75 (70-78 [51-93]) vs 61 (52-67 [37-80]) respectively, (p < 0.001). The manual control of propofol intravenous anaesthesia to target a Bispectral Index range of 55-60 may result in an unacceptable number of patients who are conscious during surgery (albeit without recall).
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the ability of Bispectral Index to detect intra operative wakefulness during total intravenous anaesthesia compared with the isolated forearm technique
Anaesthesia, 2013Co-Authors: I F RussellAbstract:It has been suggested that monitoring during total intravenous anaesthesia should include aspects of brain function. The current study used a manually adjusted target-controlled infusion of propofol for anaesthesia, guided to a Bispectral Index range of 55-60. Intra-operative responsiveness, as assessed by the isolated forearm technique, was compared with whether the Bispectral Index predicted/identified a patient's appropriate hand movements in responses to commands. Twenty-two women underwent major gynaecological surgery with total intravenous anaesthesia, propofol, remifentanil and atracurium. Sixteen women responded, on 80 occasions, with appropriate hand movements to commands during surgery, of which the Bispectral Index detected 47 (sensitivity 59%). The Bispectral Index suggested consciousness 220 times in the absence of movement responses (specificity 85%). The positive predictive value of a Bispectral Index response was 18%. While two women had vague recall about squeezing fingers, none had recall of surgery. For patients who responded more than once during surgery the Bispectral Index value associated with a response was not constant. Although there was no difference in the median (IQR [range]) effect site propofol concentration between intra-operative responses (2.0 (1.5-2.3 [1.2-4.0]) μg.ml(-1)) and eye opening after surgery (2.1 (1.7-2.8 [1.5-3.9]) μg.ml(-1)), the median (IQR [range]) Bispectral Index value at eye opening after surgery was significantly higher than that associated with responses during surgery: 75 (70-78 [51-93]) vs 61 (52-67 [37-80]) respectively, (p < 0.001). The manual control of propofol intravenous anaesthesia to target a Bispectral Index range of 55-60 may result in an unacceptable number of patients who are conscious during surgery (albeit without recall).
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The ability of Bispectral Index to detect intra-operative wakefulness during isoflurane/air anaesthesia, compared with the isolated forearm technique.
Anaesthesia, 2013Co-Authors: I F RussellAbstract:Clinical signs are unreliable for guiding anaesthetic administration and it is suggested that using the Bispectral Index can improve anaesthetic delivery. In the current study, isoflurane administration was guided to a Bispectral Index range of 55-60. Intra-operative responsiveness, as assessed by the isolated forearm technique, was compared with whether the Bispectral Index predicted/identified a patient's appropriate hand movements in response to commands. Thirty-four women underwent major gynaecological surgery with isoflurane/air and atracurium. Eleven women responded on 32 occasions with appropriate hand movements to commands given during surgery, of which the Bispectral Index detected 17 (sensitivity 53%). The Bispectral Index suggested consciousness 660 times in the absence of any movement responses (specificity 69%). The positive predictive value of the Bispectral Index was 3%. The median (IQR [range]) Bispectral Index value associated with an intra-operative response was significantly lower than that associated with eye opening after surgery: 60 (50-68 [36-83]) vs 77 (75-84 [59-90]), respectively (p = 2.25 × 10(-8)). Conversely, end-tidal isoflurane concentration was significantly higher at intra-operative response than at eye opening: 0.3 (0.3-0.4 [0.2-0.9]) vs 0.2 (0.1-0.2 [0.1-0.3]), respectively (p = 7.36 × 10(-8)). For patients who responded more than once during surgery, the Bispectral Index value associated with a response was not constant. No patient had recall for surgery or the taped commands, and only one could remember dreaming (a good dream). Titrating isoflurane to target a Bispectral Index range of 55-60 may result in an unacceptable number of patients who are conscious during surgery (albeit without recall).
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The ability of Bispectral Index to detect intra‐operative wakefulness during total intravenous anaesthesia compared with the isolated forearm technique
Anaesthesia, 2013Co-Authors: I F RussellAbstract:It has been suggested that monitoring during total intravenous anaesthesia should include aspects of brain function. The current study used a manually adjusted target-controlled infusion of propofol for anaesthesia, guided to a Bispectral Index range of 55-60. Intra-operative responsiveness, as assessed by the isolated forearm technique, was compared with whether the Bispectral Index predicted/identified a patient's appropriate hand movements in responses to commands. Twenty-two women underwent major gynaecological surgery with total intravenous anaesthesia, propofol, remifentanil and atracurium. Sixteen women responded, on 80 occasions, with appropriate hand movements to commands during surgery, of which the Bispectral Index detected 47 (sensitivity 59%). The Bispectral Index suggested consciousness 220 times in the absence of movement responses (specificity 85%). The positive predictive value of a Bispectral Index response was 18%. While two women had vague recall about squeezing fingers, none had recall of surgery. For patients who responded more than once during surgery the Bispectral Index value associated with a response was not constant. Although there was no difference in the median (IQR [range]) effect site propofol concentration between intra-operative responses (2.0 (1.5-2.3 [1.2-4.0]) μg.ml(-1)) and eye opening after surgery (2.1 (1.7-2.8 [1.5-3.9]) μg.ml(-1)), the median (IQR [range]) Bispectral Index value at eye opening after surgery was significantly higher than that associated with responses during surgery: 75 (70-78 [51-93]) vs 61 (52-67 [37-80]) respectively, (p < 0.001). The manual control of propofol intravenous anaesthesia to target a Bispectral Index range of 55-60 may result in an unacceptable number of patients who are conscious during surgery (albeit without recall).
Akitomo Matsuki - One of the best experts on this subject based on the ideXlab platform.
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Effects of nicardipine and diltiazem on the Bispectral Index and 95% spectral edge frequency
European journal of anaesthesiology, 2003Co-Authors: Kazuyoshi Hirota, Hironori Ishihara, Shizuko Kabara, Tetsuya Kushikata, Masatou Kitayama, Akitomo MatsukiAbstract:Summary Background and objective: Previous studies have shown that L-type voltage-sensitive Ca 2+ channel blocking agents increased and the L-type Ca 2+ channel activator Bay K 8644 reduced the general anaesthetic potency in animals. As the Bispectral Index correlates with the depth of sedation, we examined whether L-type Ca 2+ channel blocking agents affect the Bispectral Index. Methods: Thirty hypertensive patients (systolic arterial pressure >160 mmHg) presenting for total intravenous anaesthesia with propofol, fentanyl and ketamine were recruited. Bispectral Index monitoring was commenced directly the patients arrived in the operating theatre. All patients were given either nicardipine or diltiazem intravenously at the discretion of the anaesthesiologist in charge. Results: Twenty-three and seven patients received nicardipine or diltiazem, respectively. The Bispectral Index level (mean (95% confidence interval)) did not change with either drug. In the nicardipine group, the Bispectral Index at 0, 5, 10 and 15 min was 55 (52–58), 55 (51–59), 55 (52–59) and 56 (53–59), respectively. In the diltiazem group, values were 59 (48–71), 60 (51–70), 61 (52–71) and 61 (50–72), respectively. Both L-type Ca 2+ channel blocking agents significantly decreased arterial pressure. Conclusions: Clinical doses of nicardipine and diltiazem do not alter the Bispectral Index during general anaesthesia.
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Relation between Bispectral Index and plasma catecholamines after oral diazepam premedication.
European journal of anaesthesiology, 1999Co-Authors: Kazuyoshi Hirota, K. Matsunami, Tomoyuki Kudo, Hironori Ishihara, Akitomo MatsukiAbstract:The efficacy of anaesthetic premedication has been assessed using sedative scores or a visual analogue scale. However, in both it may be difficult to exclude evaluators' subjectivity or a placebo effect. Plasma concentration of catecholamines may also be useful for the assessment of patient anxiety. Recently Bispectral electro-encephalographic analysis has been developed, and the Bispectral Index monitor has been reported to give measurements which correlate well with the depth of sedation. In the present study, we have examined the relation between Bispectral Index values and plasma catecholamine concentrations after oral diazepam premedication. Twenty-eight patients scheduled for elective surgery were randomly assigned to one of two groups: diazepam premedication group (group D(+), n = 14) and no premedication group (group D(-), n = 14). The patients were premedicated orally with diazepam 10 mg and roxatidine 75 mg in group D(+), and with roxatidine 75 mg only in group D(-) 90 min before arrival in the operating theatre. After patients arrived in the operating theatre, the Bispectral Index monitor was applied. Venous blood samples (6 mL) were collected in the case of patients in group D(+) for the measurement of plasma catecholamines levels using high-performance liquid chromatography. The Bispectral Index level (mean +/- SD) in group D(+): 93.5 +/- 773.5 was significantly lower than that in group D(-): 96.1 +/- 1.8 (P < 0.05). There was a significant correlation between Bispectral Index and plasma norepinephrine levels (r = 0.567, P < 0.05). The present study suggests that the Bispectral Index monitor may detect the effect of oral diazepam premedication.
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The effects of nitrous oxide and ketamine on the Bispectral Index and 95% spectral edge frequency during propofol-fentanyl anaesthesia.
European journal of anaesthesiology, 1999Co-Authors: Kazuyoshi Hirota, Hironori Ishihara, T. Kubota, Akitomo MatsukiAbstract:In this study, we have sought to establish whether N2O and ketamine alter the Bispectral Index during propofol-fentanyl anaesthesia. Fourteen surgical patients were randomly assigned to one of two groups: the N2O group (n = 7) and the ketamine group (n = 7). In both groups, anaesthesia was induced with propofol 1.5-2 mg kg-1 and fentanyl 2 micrograms kg-1 and maintained with propofol 5-7 mg kg-1 hr-1 to target the Bispectral Index between 40 and 50. After the Bispectral Index value had stabilized the propofol infusion rate was fixed. In the N2O group, the following concentrations of N2O were subsequently inhaled at 20-min intervals; 20, 40, 60 and 70%, and then N2O was terminated. In the ketamine group, ketamine (0.4 mg kg-1 + 1.0 mg kg-1h-1) was given. The Bispectral Index and 95% spectral edge frequency were recorded 20 min after each change in concentration of N2O or ketamine infusion. The Bispectral Index and 95% spectral edge frequency did not change significantly in the N2O group, but increased significantly from 44.1 +/- 0.7 and 16.0 +/- 0.5 to 58.6 +/- 1.4 and 19.5 +/- 0.3 (P < 0.01), respectively, in the ketamine group. Additional N2O or ketamine did not decrease the Bispectral Index and 95% spectral edge frequency values. The depth of sedation should be assessed carefully using a Bispectral Index monitor when these anaesthetic agents are used together.
Kate Leslie - One of the best experts on this subject based on the ideXlab platform.
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propofol blood concentration and the Bispectral Index predict suppression of learning during propofol epidural anesthesia in volunteers
Anesthesia & Analgesia, 1995Co-Authors: Kate Leslie, Daniel I. Sessler, Marc Schroeder, Kristin WaltersAbstract:Propofol is often used for sedation during regional anesthesia. We tested the hypothesis that propofol blood concentration, the Bispectral Index and the 95% spectral edge frequency predict suppression of learning during propofol/epidural anesthesia in volunteers. In addition, we tested the hypothesis that the Bispectral Index is linearly related to propofol blood concentration. Fourteen healthy, male volunteers were studied on three randomly ordered days: no propofol, target propofol blood concentration 1 microgram/mL, and target propofol blood concentration 2 micrograms/mL. Each day, epidural anesthesia (approximately T11 level) was induced using 2% 2-chloroprocaine. Propofol was infused by a computer-controlled pump, and propofol concentration measured in central venous blood. We administered a Trivial Pursuit-type question task on all 3 days. The electroencephalogram was monitored continuously (Fp1, Fp2; reference, Cz; ground, mastoid). Propofol caused concentration-related impairment of learning. The propofol blood concentration suppressing learning by 50% was 0.66 +/- 0.1 microgram/mL. The Bispectral Index value when learning was suppressed by 50% was 91 +/- 1. In contrast, the 95% spectral edge frequency did not correlate well with learning. The Bispectral Index decreased linearly as propofol blood concentration increased (Bispectral Index = -7.4.[propofol] + 90; r2 = 0.47, n = 278). There was no significant correlation between the 95% spectral edge frequency and propofol concentration. In order to suppress learning, propofol blood concentrations reported to produce amnesia may be targeted. Alternatively, the Bispectral Index may be used to predict anesthetic effect during propofol sedation.
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Propofol blood concentration and the Bispectral Index predict suppression of learning during propofol/epidural anesthesia in volunteers.
Anesthesia and analgesia, 1995Co-Authors: Kate Leslie, Daniel I. Sessler, Marc Schroeder, Kristin WaltersAbstract:Propofol is often used for sedation during regional anesthesia. We tested the hypothesis that propofol blood concentration, the Bispectral Index and the 95% spectral edge frequency predict suppression of learning during propofol/epidural anesthesia in volunteers. In addition, we tested the hypothesis that the Bispectral Index is linearly related to propofol blood concentration. Fourteen healthy, male volunteers were studied on three randomly ordered days: no propofol, target propofol blood concentration 1 microgram/mL, and target propofol blood concentration 2 micrograms/mL. Each day, epidural anesthesia (approximately T11 level) was induced using 2% 2-chloroprocaine. Propofol was infused by a computer-controlled pump, and propofol concentration measured in central venous blood. We administered a Trivial Pursuit-type question task on all 3 days. The electroencephalogram was monitored continuously (Fp1, Fp2; reference, Cz; ground, mastoid). Propofol caused concentration-related impairment of learning. The propofol blood concentration suppressing learning by 50% was 0.66 +/- 0.1 microgram/mL. The Bispectral Index value when learning was suppressed by 50% was 91 +/- 1. In contrast, the 95% spectral edge frequency did not correlate well with learning. The Bispectral Index decreased linearly as propofol blood concentration increased (Bispectral Index = -7.4.[propofol] + 90; r2 = 0.47, n = 278). There was no significant correlation between the 95% spectral edge frequency and propofol concentration. In order to suppress learning, propofol blood concentrations reported to produce amnesia may be targeted. Alternatively, the Bispectral Index may be used to predict anesthetic effect during propofol sedation.
Maurice Lamy - One of the best experts on this subject based on the ideXlab platform.
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Effect of Nitrous Oxide on the Bispectral Index and the 95% Spectral Edge Frequency of the Electroencephalogram During Surgery
Anaesthesia, 2001Co-Authors: Pol Hans, Vincent Bonhomme, H. Benmansour, Pierre-yves Dewandre, Jean-françois Brichant, Maurice LamyAbstract:We studied the effect of nitrous oxide on the Bispectral Index and 95% spectral edge frequency of the electroencephalogram in 20 patients undergoing lumbar surgery under general anaesthesia combined with epidural administration of 5 mg morphine. Anaesthesia was induced with propofol and sufentanil, and maintained with sevoflurane in air/oxygen adjusted to keep the Bispectral Index between 40 and 60. One and a half hours after the start of surgery, nitrous oxide was administered in a randomised sequence of concentrations (20, 40 and 60% end-expired). Under steady-state conditions, mean (SD) Bispectral Index and spectral edge frequency decreased as end-tidal concentration of nitrous oxide increased, from 47.7 (4.3) and 15.6 (1.3) at 0% nitrous oxide to 39.8 (6.3) and 14.3 (1.8) at 60% nitrous oxide. A negative correlation was found between nitrous oxide concentration and Bispectral Index (r = -0.48; p < 0.01) and spectral edge frequency (r = -0.39; p < 0.05). We conclude that this dose-dependent decrease in Bispectral Index and spectral edge frequency induced by nitrous oxide may reflect the level of analgesia associated with the anaesthetic regimen.
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Effect of epidural bupivacaine on the relationship between the Bispectral Index and end-expiratory concentrations of desflurane.
Anaesthesia, 1999Co-Authors: Pol Hans, Pierre-yves Dewandre, Jean-françois Brichant, Jean-pierre Lecoq, Maurice LamyAbstract:We compared the relationship between the Bispectral Index and end-tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or 10 ml bupivacaine 0.125% with epinephrine 1/800 000 (group B) before induction of anaesthesia with sufentanil (0.15 μg.kg−1) and propofol (2 mg.kg−1); muscle relaxation was obtained with cisatracurium (0.2 mg.kg−1). Patients lungs were ventilated to maintain end-tidal desflurane at 3% in O2/N2O (50/50) until 5 min after skin incision, followed by two consecutive 10 min periods at end-tidal desflurane 6% and 9%. Bispectral Index values were recorded before induction, at 3% desflurane before and 5 min after skin incision, and at 6% and 9% end-tidal desflurane. Bispectral Index decreased with increasing end-tidal desflurane concentration (anova: p