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Bispectral Index (bispectral + index)
Terms modified by Bispectral Index Selected AbstractsUse of the Bispectral Index monitor to aid titration of propofol during a drug-assisted interviewPEDIATRIC ANESTHESIA, Issue 2 2001Greta M. Palmer MB We report two drug-assisted interviews with propofol in an 18-year-old with the diagnosis of Complex Regional Pain Syndrome type 1. We describe difficulty in titration of propofol in the first interview. Consequently, in the second interview, the Bispectral Index (BIS) monitor was applied to assist adjustment of the propofol infusion. This facilitated the achievement of a prolonged sedative-hypnotic state for a successful neuropsychological evaluation. Pertinent information was obtained from this patient. However, the role of drug-assisted interviews as a technique needs to be further elucidated. [source] Insertion and use of the LMA SupremeÔ in the prone position,ANAESTHESIA, Issue 2 2010A. M. López Summary We investigated whether insertion of an LMA SupremeÔ and its use for maintenance of anaesthesia is feasible in the prone position. Forty adult patients positioned themselves prone and were given propofol until the Bispectral Index was < 50. A size-4 LMA Supreme was inserted by experienced anaesthetists. Ease of insertion, ease of ventilation, efficacy of seal, ease of gastric tube insertion, blood staining, postoperative sore throat, and other complications were recorded. Insertion was successful at the first and second attempt in 37 (92.5%) and 3 (7.5%) patients, respectively. The mean (SD) insertion time was 21 (15) s. Oropharyngeal leak pressure was greater in females than males (29 (4) vs 25 (4) cmH2O, respectively, p = 0.01). Adequate ventilation was achieved in all patients. Gastric tube placement was successful in all patients. The frequency of blood staining and sore throat was 7.5% each. No other complications were noted. We conclude that use of the LMA Supreme in the prone position by experienced users is feasible. [source] Comparison of closed loop vs. manual administration of propofol using the Bispectral index in cardiac surgeryACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 3 2009J. AGARWAL Background: In recent years, electroencephalographic indices of anaesthetic depth have facilitated automated anaesthesia delivery systems. Such closed-loop control of anaesthesia has been described in various surgical settings in ASA I,II patients (1,4), but not in open heart surgery characterized by haemodynamic instability and higher risk of intra-operative awareness. Therefore, a newly developed closed-loop anaesthesia delivery system (CLADS) to regulate propofol infusion by the Bispectral index (BIS) was compared with manual control during open heart surgery. Methods: Forty-four adult ASA II,III patients undergoing elective cardiac surgery under cardiopulmonary bypass were enrolled. The study participants were randomized to two groups: the CLADS group received propofol delivered by the CLADS, while in the manual group, propofol delivery was adjusted manually. The depth of anaesthesia was titrated to a target BIS of 50 in both the groups. Results: During induction, the CLADS group required lower doses of propofol (P<0.001), resulting in lesser overshoots of BIS (P<0.001) and mean arterial blood pressure (P=0.004). Subsequently, BIS was maintained within ± 10 of the target for a significantly longer time in the CLADS group (P=0.01). The parameters of performance assessment, median absolute performance error (P=0.01), wobble (P=0.04) and divergence (P<0.001), were all significantly better in the CLADS group. Haemodynamic stability was better in the CLADS group and the requirement of phenylephrine in the pre-cardiopulmonary bypass period as well as the cumulative dose of phenylephrine used were significantly higher in the manual group. Conclusion: The automated delivery of propofol using CLADS was safe, efficient and performed better than manual administration in open heart surgery. [source] Different bispectral index values from both sides of the forehead in unilateral carotid artery stenosisACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2009E. H. LEE Bispectral index (BIS) values derived from the left and right forehead are usually the same. We report on two patients with unilateral carotid artery stenosis in whom we observed differences between the BIS values obtained from sensors placed on each side of the forehead. During surgery, the BIS values of the diseased side decreased more than those of the opposite side when the mean arterial pressure decreased below 70 mmHg. BIS monitors should be used with caution in patients with unilateral carotid artery and cerebrovascular disease. [source] Bispectral index, predicted and measured drug levels of target-controlled infusions of remifentanil and propofol during laparoscopic cholecystectomy and emergenceACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2000S. C. Høymork Background: Target-controlled infusions (TCI) have been launched as simple, accurate and reliable delivery systems of intravenous drugs. Bispectral index of EEG (BIS) seems promising in measuring hypnotic effect of anaesthetic drugs. The aims of this study were to evaluate the accuracy of TCI systems in patients undergoing laparoscopic cholecystectomy and to correlate measured drug levels to BIS values. Data were analysed for possible gender differences during emergence. Methods: After written informed consent, 20 patients were enrolled in an open study. Remifentanil was set at 7.5 ng/ml as target throughout the whole procedure, and propofol at 5 ,g/ml at induction and 3 ,g/ml after intubation. Values in blood samples of remifentanil and propofol were correlated to the estimated values and to systolic blood pressure and BIS. BIS values and measured drug levels during emergence and emergence time were compared for the two sexes. Results: Measured drug values varied considerably from the set target with a prediction error of ,22% for remifentanil and 49% for propofol. The anaesthesia level was regarded as quite deep with a mean BIS during stable surgery of 42±7, and at this level we found no correlation between measured values of either of the two drugs and BIS. The emergence time was significantly shorter for women (12.6±2.5 min) than for men (19.0±4.2 min) (P=0.001), with no significant differences in measured levels of propofol or remifentanil or BIS during the emergence period. Conclusion: Present systems for TCI of remifentanil and propofol result in large intra- and interindividual variations in measured drug levels, and measured levels differ from target. There may be possible interaction between the two anaesthetics at a pharmacokinetic level. Within the level of anaesthesia studied here, BIS was not an indicator of the actual drug levels. Women woke up significantly faster than men. [source] Bispectral index in pediatrics: fashion or a new tool?PEDIATRIC ANESTHESIA, Issue 3 2005ISABELLE MURAT MD First page of article [source] Differences between bispectral index and spectral entropy during xenon anaesthesia: a comparison with propofol anaesthesiaANAESTHESIA, Issue 6 2010J. Höcker Summary We enrolled 114 patients, aged 65,83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy. [source] Bispectral index during cardiopulmonary resuscitation: a poor indicator of recovery.ANAESTHESIA, Issue 2 2010Two very different cases Summary We report two cases of massive intra-operative bleeding during lung transplantation requiring emergency cardiopulmonary bypass. In both cases the bispectral index dropped to 0, remained low for around 30 and 90 min respectively, and then returned to values consistent with a usual anaesthetic state (around 40). At the time bispectral monitoring provided some reassurance to the medical team about the adequacy of the resuscitation. However, this proved misleading since postoperative neurological recovery was favourable in one case but not in the other. [source] Assessing the clinical or pharmaco-economical benefit of target controlled desflurane delivery in surgical patients using the Zeus® anaesthesia machine,ANAESTHESIA, Issue 11 2009B. Lortat-Jacob Summary The Zeus® anaesthesia machine includes an auto-control mode which allows targeting of end-tidal volatile and inspired oxygen concentrations. We assessed the clinical benefits and economic impact of this target-controlled anaesthesia compared with conventional manually controlled anaesthesia. Eighty patients were randomly assigned to receive desflurane either with a fresh gas flow set by the anaesthetist or in auto-control mode. Drug delivery was adjusted to maintain bispectral index between 40,60 units and systolic arterial pressure under 15 mmHg above its pre-induction value (upper limit) and over 90 mmHg (lower limit). Blood pressure was maintained in the desired range for 89% and 91% of the maintenance period for auto-control and manual control respectively (p = 0.49). Bispectral index was in the desired range for 82% and 79% of the maintenance period, for auto-control and manual control respectively (p = 0.46). Oxygen consumption was more than halved by the use of auto-control mode, and mean (SD) desflurane consumption during surgery was 0.07 (0.04) vs 0.2 (0.07) ml.min,1 in auto-control and manual control respectively (p < 0.0001). The number of drug delivery adjustments per hour was significantly lower in auto-control mode (mean (SD) 7 (2) vs 15 (12); p < 0.0001). Thus, the auto-control mode provided similar haemodynamic stability and bispectral control as did conventional manually controlled anaesthesia, but led to a reduction in gas and vapour consumption with a more clinically acceptable workload. [source] Monitoring seizures with the Bispectral indexANAESTHESIA, Issue 10 2004R. E. Tallach No abstract is available for this article. [source] A clinical prospective comparison of anesthetics sensitivity and hemodynamic effect among patients with or without obstructive jaundiceACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2010L.-Q. YANG Background: To compare isoflurane anesthesia in patients with or without hyperbilirubinemia undergoing hepatobiliary surgery. Methods: Forty-two patients with obstructive jaundice and 40 control patients with normal liver function scheduled for hepatobiliary surgery under isoflurane anesthesia were studied. Anesthesia was induced with propofol (1.5,2 mg/kg) and remifentanil (2 ,g/kg). After tracheal intubation, anesthesia was titrated using isoflurane in oxygen-enriched air, adjusted to maintain a bispectral index (BIS) value of 46,54. Ephedrine, atropine and remifentanil were used to maintain hemodynamic parameters within 30% of the baseline. The mean arterial blood pressure (MAP), heart rate (HR), drug doses and the time taken to recover from anesthesia were recorded. Results: Demographic data, duration and BIS values were similar in both groups. Anesthesia induction and maintenance were associated with more hemodynamic instability in the patients with jaundice and they received more ephedrine and atropine and less remifentanil and isoflurane (51.1±24.2 vs. 84.6±20.3 mg/min; P for all <0.05) than control patients. Despite less anesthetic use, the time to recovery and extubation was significantly longer than that in control. Conclusion: Patients with obstructive jaundice have an increased sensitivity to isoflurane, more hypotension and bradycardia during anesthesia induction and maintenance and a prolonged recovery time compared with controls. [source] Depth of anaesthesia and post-operative cognitive dysfunctionACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2010J. STEINMETZ Background: A deep level of anaesthesia measured by the bispectral index has been found to improve processing speed as one aspect of cognitive function after surgery. The purpose of the present study was to assess the possible effect of the level of anaesthesia on post-operative cognitive dysfunction (POCD) 1 week after surgery, as assessed by a neuropsychological test battery. Methods: We included 70 patients >60 years of age scheduled for elective non-cardiac surgery with general anaesthesia. The depth of anaesthesia was monitored using the cerebral state monitor, which provided a cerebral state index (CSI) value. Cognitive function was assessed by the ISPOCD neuropsychological test battery before and at 1 week (or hospital discharge) after surgery and POCD was defined as a Z score above 1.96. Results: Five patients were not assessed after surgery. The mean CSI was 40 and 43 in patients with (N=9) and without POCD (N=56), respectively (P=0.41). The cumulated time of both deep anaesthesia (CSI<40) and light anaesthesia (CSI>60) did not differ significantly, and no significant correlation was found between the mean CSI and the Z score. Conclusion: We were unable to detect a significant association between the depth of anaesthesia and the presence of POCD 1 week after the surgery. [source] On-Pump Beating Heart Versus Hypothermic Arrested Heart Valve Replacement SurgeryJOURNAL OF CARDIAC SURGERY, Issue 2 2008Ümit Karadeniz M.D. Methods: Fifty valvular surgery patients were randomly assigned into three groups. Sixteen patients underwent beating heart valve replacement with normothermic bypass without cross-clamping the aorta, 17 patients underwent the same procedure with cross-clamping the aorta and retrograde coronary sinus perfusion, and the remaining 17 patients had conventional surgery with hypothermic bypass and cardioplegic arrest. Results: Two-channel electroencephalography (EEG) was recorded to assess changes in cerebral cortical synaptic activity and 95% spectral edge frequency values were recorded continuously. Bispectral monitoring was used to measure the depth of anesthesia. Blood flow rates in middle cerebral artery (MCA) were measured by transcranial Doppler (TCD). Reduction in spectral edge frequency (>50%) or bispectral index (BIS) (<20) or transcranial Doppler flow velocity (>50%) was detected in four patients in Group 1, five patients in Group 2, and three patients in Group 3. BIS or EEG values never reached zero, which indicates isoelectric silence during surgery. Gross neurological examinations were normal in all patients postoperatively. Conclusion: There is no difference regarding neurological monitoring results between on-pump beating heart and hypothermic arrested heart valve replacement surgery. Also no significant difference was encountered among the groups regarding the clinical outcomes. [source] Prospective evaluation of the time to peak effect of propofol to target the effect site in childrenACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009H. R. MUÑOZ Background: The plasma-effect site equilibration rate constant (ke0) of propofol has been determined in children with the use of the time to maximum effect (tpeak), however, it has not been validated. The objective was to measure the tpeak; of propofol with two depths of anesthesia monitors in children and to evaluate these measurements with a target-controlled infusion (TCI) system. Methods: Unpremedicated, ASA I children from 3 to 11 years were studied. In Part 1, children were monitored simultaneously with the bispectral index (BIS) and the A-Line ARX-index (AAI) from the Alaris A-Line auditory-evoked potential monitor/2. The tpeak after a bolus dose of propofol was measured. In Part 2, the tpeak measured was used to target the effect site with a TCI system. The median (MD) and the absolute median (MDA) difference between the predicted time of peak concentration at the effect site (Ce) and the measured time of peak effect in the index of depth of anesthesia (terror) was used to evaluate the performance of the system. Results: The BIS recordings were of a better quality than the AAI. The mean ± standard deviation tpeak was 65 ± 14 s with the BIS (n=25) and 201 ± 74 s with the AAI (n=10)(P<0.001). Validation was only performed with the BIS monitor in 40 children, yielding an MD terror of ,9.5 s and an MDA terror of 10.0 s. Conclusions: The small delay between the evolution of Ce of propofol and the observed effect suggests that this can be a useful model to target the effect site in children. [source] Influence of hypobaric hypoxia on bispectral index and spectral entropy in volunteersACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009T. IKEDA Background: Hypoxia has been shown to change electroencephalogram parameters including frequency and amplitude, and may thus change bispectral index (BIS) and spectral entropy values. If hypoxia per se changes BIS and spectral entropy values, BIS and spectral entropy values may not correctly reflect the depth of anaesthesia during hypoxia. The aim of this study was to examine the changes in BIS and spectral entropy values during hypobaric hypoxia in volunteers. Methods: The study was conducted in a high-altitude chamber with 11 volunteers. After the subjects breathed 100% oxygen for 15 min at the ground level, the simulated altitude increased gradually to the 7620 m (25,000 ft) level while the subjects continued to breathe oxygen. Then, the subjects discontinued to breath oxygen and breathed room air at the 7620 m level for up to 5 min until they requested to stop hypoxic exposure. Oxygen saturation (SpO2), heart rate, 95% spectral edge frequency (SEF), BIS, response entropy (RE), and state entropy (SE) of spectral entropy were recorded throughout the study period. Results: Of the 11 subjects, seven subjects who underwent hypoxic exposure for 4 min were analysed. SpO2 decreased to 69% at the 7620 m level without oxygen. However, SEF, BIS, RE, and SE before and during hypoxic exposure were almost identical. Conclusion: These data suggest that hypoxia of oxygen saturation around 70% does not have a strong effect on BIS and spectral entropy. [source] Midazolam dose for loss of response to verbal stimulation during the unilateral or bilateral spinal anesthesiaACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2009M. J. YUN Background: We have conducted this study to investigate whether unilateral or bilateral spinal anesthesia with bupivacaine induces different sensitivity to intravenous (i.v.) midazolam for sedation. Methods: Forty-two patients undergoing various elective unilateral lower extremity surgeries were allocated into two groups: (1) unilateral spinal anesthesia group (Group US, n=21; heavy bupivacaine 5 mg/ml, 9 mg) and (2) bilateral spinal anesthesia group (Group BS, n=21; heavy bupivacaine 5 mg/ml, 9 mg). One milligram of midazolam was injected i.v. at 30-s intervals until the patients did not respond to the hand grasp test beginning 15 min after spinal anesthesia. The concentration of plasma bupivacaine was evaluated every 15 min for the first 75 min after the start of the spinal anesthesia, and the bispectral index was monitored continuously. Results: The mean venous plasma concentration of bupivacaine was not significantly different between Group US and BS. The dose of midazolam required to abolish responses to verbal commands was significantly lower in Group BS (mean 5.9±1.2 mg) vs. Group US (mean 9.0±1.4 mg). Conclusions: A higher dosage of midazolam is required for loss of response to verbal stimulation during unilateral spinal anesthesia than during bilateral spinal anesthesia. [source] Pre-oxygenation enhances induction with sevoflurane as assessed using bispectral index monitoringACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2006A. Fassoulaki Background:, Several methods may enhance the inhalational induction of anesthesia. In this randomized double-blind study, we evaluated the speed of induction of anesthesia with sevoflurane with or without pre-oxygenation. Methods:, Fifty-four patients scheduled for hysteroscopy received for 10 min air or 100% oxygen via a facemask followed by , 7% sevoflurane in 100% oxygen. During the first 300 s of sevoflurane administration, bispectral index (BIS) values were recorded every 30 s in all patients. In 14 patients, seven in each group, BIS, endtidal CO2, tidal volume, respiratory rate, SpO2, and heart rate were recorded every minute during the pre-induction period and every 30 s during the first 5 min of sevoflurane administration. Results:, The BIS, endtidal CO2, tidal volume and respiratory rate did not differ between the oxygen or air breathing groups (P = 0.696, P = 0.999, P = 0.388, and P = 0.875, respectively), though the oxygen group exhibited lower tidal volumes by 16,20%. The SpO2 and heart rates were higher in the oxygen breathing group (P < 0.001 and P = 0.042, respectively). During sevoflurane administration, BIS values were lower in the oxygen group vs. the group breathing air, in particular at 90, 120, 150, 180 and 210 s (P = 0.001, P = 0.001, P = 0.001, P = 0.001 and P = 0.030, respectively). The endtidal CO2 and the tidal volumes between the groups did not differ. The two groups differed in the SpO2 and the heart rates during induction (P = 0.004 and 0.003, respectively). Conclusions:, Before sevoflurane administration, breathing 100% oxygen for 10 min enhances induction of anesthesia with sevoflurane. [source] Suppression of the human spinal H-reflex by propofol: a quantitative analysisACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2006J. H. Baars Background:, The spinal cord is an important site of anaesthetic action because it mediates surgical immobility. During anaesthesia with volatile anaesthetics, it has been shown that the suppression of the spinal H-reflex correlates with surgical immobility. To evaluate whether the H-reflex could also be a possible candidate for monitoring immobility during propofol anaesthesia, this study assessed the concentration-dependent suppression of the H-reflex by propofol. To discriminate different effect sites, the individual concentration response-curves and the t1/2ke0 of the H-reflex have been compared with those of two EEG parameters. Methods:, In 18 patients, anaesthesia was induced and maintained with propofol infused using a target-controlled infusion pump at stepwise increasing and decreasing plasma concentrations between 0.5 and 4.5 mg/l. The H-reflex of the soleus muscle was recorded at a frequency of 0.1 Hz. Calculated propofol concentrations and H-reflex amplitude were analysed in terms of a pharmacokinetic-pharmacodynamic (PKPD) model with a sigmoid concentration-response function. Results:, For slowly increasing propofol concentrations, computer fits of the PKPD model for H-reflex suppression by propofol yielded the following median parameters: EC50 1.1 (0.8,1.7) mg/l, slope parameter 2.4 (2.0,3.7), and a t1/2ke0 of 6.7 (2.8,7.5, 25,75% quantiles) min. For the bispectral index, the t1/2ke0 was 2.2 (1.8,3.1) min and for the spectral edge frequency at the 95th percentile of the power spectrum 2.8 (1.9,3.2) min. Conclusions:, Propofol, unlike sevoflurane, suppresses the spinal H-reflex at concentrations far lower than the C50 skin incision. The differences in t1/2ke0 -values indicate the presence of different effect compartments for effects on the H-reflex and the EEG. [source] Comparison of recovery properties of desflurane and sevoflurane according to gender differencesACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 2 2005E. Tercan Background:, The aim of this study was to investigate the recovery properties of desflurane and sevoflurane in patients undergoing elective surgery, according to the gender differences. Methods:, In the study, 160 ASA class I,II patients aged between 20 and 60 years were included. The patients were assigned into two groups according to their gender, and these groups were randomly divided into two groups according to a selected volatile anaesthetic agent. Intraoperative bispectral index, time of postoperative achievement for end-tidal concentrations of volatile agents to decline 50% (ET-AA%50), time for extubation, time for eye opening and orientation, and time for bispectral index values to reach control values were recorded. Aldrete scores and error points of a delayed memory recall test were determined. Results:, Desflurane groups had a shorter ET-AA%50 time, extubation and eye-opening time in male and female patients compared to the sevoflurane groups, and these results were statistically significant (P < 0.05). In both the desflurane and sevoflurane groups, ET-AA%50 time, extubation and eye-opening time were shorter in male patients than in female patients, and these results were also statistically significant (P < 0.05). There were no significant differences among the groups in terms of Aldrete scores and error points of delayed memory recall test (P > 0.05). Conclusion:, In conclusion, early recovery time was shorter in male patients compared to female patients in both the desflurane and sevoflurane groups. Additionally, in the desflurane groups it was shorter in the sevoflurane groups for both genders. [source] Effects of subanaesthetic and anaesthetic doses of sevoflurane on regional cerebral blood flow in healthy volunteers.ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 10 2004A positron emission tomographic study Background:, We tested the hypothesis that escalating drug concentrations of sevoflurane are associated with a significant decline of cerebral blood flow in regions subserving conscious brain activity, including specifically the thalamus. Methods:, Nine healthy human volunteers received three escalating doses using 0.4%, 0.7% and 2.0% end-tidal sevoflurane inhalation. During baseline and each of the three levels of anaesthesia one PET scan was performed after injection of . Cardiovascular and respiratory parameters were monitored and electroencephalography and bispectral index (BIS) were registered. Results:, Sevoflurane decreased the BIS values dose-dependently. No significant change in global cerebral blood flow (CBF) was observed. Increased regional CBF (rCBF) in the anterior cingulate (17,21%) and decreased rCBF in the cerebellum (18,35%) were identified at all three levels of sedation compared to baseline. Comparison between adjacent levels sevoflurane initially (0 vs. 0.2 MAC) decreased rCBF significantly in the inferior temporal cortex and the lingual gyrus. At the next level (0.2 MAC vs. 0.4 MAC) rCBF was increased in the middle temporal cortex and in the lingual gyrus, and decreased in the thalamus. At the last level (0.4 MAC vs. 1 MAC) the rCBF was increased in the insula and decreased in the posterior cingulate, the lingual gyrus, precuneus and in the frontal cortex. Conclusion:, At sevoflurane concentrations at 0.7% and 2.0% a significant decrease in relative rCBF was detected in the thalamus. Interestingly, some of the most profound changes in rCBF were observed in structures related to pain processing (anterior cingulate and insula). [source] Continuous Vagus Nerve Stimulation Effects on the Gut-Brain Axis in SwineNEUROMODULATION, Issue 1 2007Idoia Díaz-Güemes DVM ABSTRACT Objectives., This study was designed to assess vagus nerve stimulation effects on the food intake pattern in swine and determine the electrical stimulus direction. Material and Methods., Fifteen Large White pigs were randomly divided into three groups, groups A,C. All animals underwent implantation of a vagus nerve stimulator at the gastro-esophogeal junction. In group A, the stimulation was switched off, whereas stimulation was switched on in groups B and C. Food intake and body weight were registered in groups A and B, but not in group C, which was used to measure direction of stimulation in the vagus and effect on heart rate and blood pressure. Variables measured in group C included the bispectral index, blood pressure, and heart rate. A Student's t -test and one-way analysis of variance were used to detect differences between groups. All animals were sacrificed to identify effects of implantation and stimulation on the vagus nerve. Results., With respect to food intake, there was no difference between groups A and B; however, body weight did register a continuous increase. During stimulation, in group C arterial pressures decreased significantly, whereas the heart rate and bispectral index increased. Conclusion., The stimulation protocol applied in this study was insufficient to cause changes in the feeding behavior of swine; however, it did increase central nervous system activity. [source] Effects of dexmedetomidine on intraoperative motor and somatosensory evoked potential monitoring during spinal surgery in adolescentsPEDIATRIC ANESTHESIA, Issue 11 2008JOSEPH D. TOBIAS MD Summary Background:, Dexmedetomidine may be a useful agent as an adjunct to an opioid,propofol total intravenous anesthesia (TIVA) technique during posterior spinal fusion (PSF) surgery. There are limited data regarding its effects on somatosensory (SSEPs) and motor evoked potentials (MEPs). Methods:, The data presented represent a retrospective review of prospectively collected quality assurance data. When the decision was made to incorporate dexmedetomidine into the anesthetic regimen for intraoperative care of patients undergoing PSF, a prospective evaluation of its effects on SSEPs and MEPs was undertaken. SSEPs and MEPs were measured before and after the administration of dexmedetomidine in a cohort of pediatric patients undergoing PSF. Dexmedetomidine (1 ,g·kg,1 over 20 min followed by an infusion of 0.5 ,g·kg,1·h,1) was administered at the completion of the surgical procedure, but prior to wound closure as an adjunct to TIVA which included propofol and remifentanil, adjusted to maintain a constant depth of anesthesia as measured by a BIS of 45,60. Results:, The cohort for the study included nine patients, ranging in age from 12 to 17 years, anesthetized with remifentanil and propofol. In the first patient, dexmedetomidine was administered in conjunction with propofol at 110 ,g·kg,1·min,1 which resulted in a decrease in the bispectral index from 58 to 31. Although no significant effect was noted on the SSEPs (amplitude or latency) or the MEP duration, there was a decrease in the MEP amplitude. The protocol was modified so that the propofol infusion was incrementally decreased during the dexmedetomidine infusion to achieve the same depth of anesthesia. In the remaining eight patients, the bispectral index was 52 ± 6 at the start of the dexmedetomidine loading dose and 49 ± 4 at its completion (P = NS). There was no statistically significant difference in the MEPs and SSEPs obtained before and at completion of the dexmedetomidine loading dose. Conclusion:, Using the above-mentioned protocol, dexmedetomidine can be used as a component of TIVA during PSF without affecting neurophysiological monitoring. [source] Effect of oral midazolam premedication on the awakening concentration of sevoflurane, recovery times and bispectral index in childrenPEDIATRIC ANESTHESIA, Issue 5 2001Keith K. Brosius MD Background: We sought to determine the influence of preoperative oral midazolam on: (i) measures of anaesthetic emergence; (ii) recovery times and (iii) intraoperative bispectral index (BIS) measurements during sevoflurane/N2O anaesthesia in paediatric patients. Methods: Fifty-two patients, aged 1,10 years, ASA I,II, were enrolled in a prospective double-blinded study. Patients were randomized to receive either midazolam 0.5 mg·kg,1 (M) or midazolam vehicle (P) as premedication. After inhalation induction and intubation, expired sevoflurane was stabilized at 3% in 60% N2O and the corresponding BIS (BIS I) recorded. At the completion of surgery, sevoflurane was stabilized at 0.5% and the BIS (BIS E) again recorded. Awakening time, expired sevoflurane/N2O awakening concentrations and recovery times were recorded. Results: There were no significant differences between groups in awakening time, sevoflurane or N2O awakening concentrations, time to PACU discharge, time to hospital discharge or in BIS I and BIS E measurements. [source] Preliminary application of processed electroencephalogram monitoring to differentiate senile dementia from depressionPSYCHOGERIATRICS, Issue 3 2009Norihito OSHIMA Abstract Background:, It is difficult, but important, to distinguish between dementia and depression in old age because senile depression has atypical symptoms, including cognitive impairment and memory disorder. Now brain computed tomography, magnetic resonance imaging, single photon emission computed tomography, and positron emission tomography can be used to differentiate between these two conditions. However, these methods are expensive and not always available. In the present case series, we assessed the potential of monitoring the bispectral index to distinguish between dementia and depression. Methods:, A processed electroencephalogram monitor (bispectral index (BSI) monitor) was used to assess brain activity during relaxed wakefulness in 12 participants (seven with Alzheimer's disease (AD), three with depression, and two healthy volunteers). Each recording lasted 5 min and four variables (i.e. BSI, 95% spectral edge frequency, electromyogram activity, and signal quality index) were monitored. Results:, The BSI was significantly smaller in AD patients than in patients with depression (P < 0.05) and the 95% spectral edge frequency tended to be lower in AD patients than in patients with depression (P = 0.26). Slow waves were found in patients with AD and beta waves were predominant in patients with depression and healthy volunteers. Conclusion:, In conclusion, the BSI and 95% spectral edge frequency were slightly smaller in dementia patients than in patients with depression. Paroxysmal slow waves may account for the low bispectral index. Thus, BSI monitoring may become a useful tool with which to distinguish AD from depression. [source] A comparison of SNAP II© and bispectral index monitoring in patients undergoing sedationANAESTHESIA, Issue 8 2010S. R. Springman Summary Clinical signs and patients' verbal responses have traditionally been used to assess patients' comfort and the depth of sedation. Recently, level-of-consciousness monitors have been used to guide sedation. The SNAP II© is a single-lead electroencephalogram device that displays a SNAP© Index , a derived value based on both high and low frequency electroencephalogram signals. Much of the current clinical research on monitoring during sedation involves the bispectral index monitor. We compared simultaneous readings recorded by the SNAP II and bispectral index during sedation in 51 consecutive patients undergoing surgery. The anaesthesia team was blinded to the SNAP II and bispectal index values. Concurrent SNAP II and bispectral index readings displayed similarly-shaped trajectories during sedation, but further studies are needed to establish the routine clinical utility of both these monitors. [source] Differences between bispectral index and spectral entropy during xenon anaesthesia: a comparison with propofol anaesthesiaANAESTHESIA, Issue 6 2010J. Höcker Summary We enrolled 114 patients, aged 65,83 years, undergoing elective surgery (duration > 2h) into a randomised, controlled study to evaluate the performance of bispectral index and spectral entropy for monitoring depth of xenon versus propofol anaesthesia. In the propofol group, bispectral index and state entropy values were comparable. In the xenon group, bispectral index values resembled those in the propofol group, but spectral entropy levels were significantly lower. Mean arterial blood pressure was higher and heart rate was lower in the xenon group than in the propofol group. Bispectral index and spectral entropy considerably diverged during xenon but not during propofol anaesthesia. We therefore conclude that these measures are not interchangeable for the assessment of depth of hypnosis and that bispectral index is likely to reflect actual depth of anaesthesia more precisely compared with spectral entropy. [source] Bispectral index during cardiopulmonary resuscitation: a poor indicator of recovery.ANAESTHESIA, Issue 2 2010Two very different cases Summary We report two cases of massive intra-operative bleeding during lung transplantation requiring emergency cardiopulmonary bypass. In both cases the bispectral index dropped to 0, remained low for around 30 and 90 min respectively, and then returned to values consistent with a usual anaesthetic state (around 40). At the time bispectral monitoring provided some reassurance to the medical team about the adequacy of the resuscitation. However, this proved misleading since postoperative neurological recovery was favourable in one case but not in the other. [source] Assessing the clinical or pharmaco-economical benefit of target controlled desflurane delivery in surgical patients using the Zeus® anaesthesia machine,ANAESTHESIA, Issue 11 2009B. Lortat-Jacob Summary The Zeus® anaesthesia machine includes an auto-control mode which allows targeting of end-tidal volatile and inspired oxygen concentrations. We assessed the clinical benefits and economic impact of this target-controlled anaesthesia compared with conventional manually controlled anaesthesia. Eighty patients were randomly assigned to receive desflurane either with a fresh gas flow set by the anaesthetist or in auto-control mode. Drug delivery was adjusted to maintain bispectral index between 40,60 units and systolic arterial pressure under 15 mmHg above its pre-induction value (upper limit) and over 90 mmHg (lower limit). Blood pressure was maintained in the desired range for 89% and 91% of the maintenance period for auto-control and manual control respectively (p = 0.49). Bispectral index was in the desired range for 82% and 79% of the maintenance period, for auto-control and manual control respectively (p = 0.46). Oxygen consumption was more than halved by the use of auto-control mode, and mean (SD) desflurane consumption during surgery was 0.07 (0.04) vs 0.2 (0.07) ml.min,1 in auto-control and manual control respectively (p < 0.0001). The number of drug delivery adjustments per hour was significantly lower in auto-control mode (mean (SD) 7 (2) vs 15 (12); p < 0.0001). Thus, the auto-control mode provided similar haemodynamic stability and bispectral control as did conventional manually controlled anaesthesia, but led to a reduction in gas and vapour consumption with a more clinically acceptable workload. [source] Spike-monitoring of anaesthesia for corpus callosotomy using bilateral bispectral indexANAESTHESIA, Issue 7 2009S. Ogawa Summary During corpus callosotomy for intractable epilepsy, the electrocorticogram is commonly recorded from electrodes placed on the brain surface to monitor of epileptic activity and assess the synchronisation of epileptic signals between the left and the right hemispheres. We evaluated the usefulness of bilateral bispectral index monitoring using two monitors and two sensors placed above the frontal region. Spikes were readily detected on the electroencephalogram on the bispectral index monitor, and the frequency of their occurrence increased or decreased in response to adjustment of the sevoflurane concentration. The disappearance of synchronisation between the left and the right hemispheres was observed with use of the bispectral index , in concordance with the electrocorticogram. Thus, ,spike-monitoring anaesthesia' using bilateral bispectral index was useful in assessing both the effect of anaesthetics on the electroencephalogram signals and the surgical therapeutic effect. [source] | ||||||||||