Value Of BIS Research Articles

The new pincer-type NHCs obtained by synthesizing Ag(I)-NHC complexes with various tails containing hydroxyl or acetate derivatives: Structural properties and in vitro antibacterial activities

This article discusses the synthesis, chemistry, and uses of transition metal complexes containing functionalized N-Heterocyclic carbenes (NHCs). NHCs were obtained by coupling functional group compounds containing ethyl acetate, propyl acetate, and ethanol to the 5,6-dimethylbenzimidazole compound. Thermogravimetric analysis (TGA), FT-IR, and solution (1H and 13C) NMR spectroscopy were used to characterize the elements in these compounds, and Rietveld analysis using X-ray powder diffraction (XPD) and ICP (Inductively Coupled Plasma) data was used to determine their structures. Major uses include catalyst modification and immobilization using a functional group to immobilize catalysts on a 5,6-dimethylbenzimidazole derivative support. The effects of the drug ampicillin were compared with the antimicrobial activities of 3a-c and 4a-c determined by the minimum inhibitory concentration (MIC; μg/ml). The MIC value of the compound bis(1,3-bis(3-ethoxy-3-oxopropyl)-5,6-dimethyl-1H-3λ4-benzo[d]imidazol-2-ylidene)silver(I)hexafluorophosphate (4b) was measured as 0.25 ± 2.05 μg/mL. This value indicates that this complex has strong antibacterial abilities.

Application value of BIS and S100β combined with Copeptin in patients with acute severe carbon monoxide poisoning

Objective: To explore the application value of bispectral index(BIS) , specific protein 100β(S100β) combined with Copeptinin patients with acute severe carbon monoxide poisoning (ASCMP). Methods: A total of 256 patients with acute carbon monoxide poisoning admitted to Hengshui People's Hospital from June 2018 to June 2020 were collected, and they were divided into 30 mild cases, 40 moderate cases and 186 severe cases according to the degree of poisoning. Among them, patients with severe carbon monoxide poisoning were divided into a poor prognosis group (20 cases) and a good prognosis group (166 cases) according to whether adverse events occurred. The changes of creatine kinase isoenzyme (CK-MB) , N-terminal precursor B-type brain natriuretic peptide (NT-proBNP) , BIS, S100β, and Copeptin in poisoned patients were measured. Logistic regression analysis and receiver operating characteristic (ROC) curve were used to evaluate the significance of relevant indicators for ASCMP patients. Results: Compared with the mild-to-moderate group, CK-MB, NT-proBNP, S100β, Copeptin increased, and BIS value decreased in the severe group (P< 0.05). 24 hours after admission, compared with the good prognosis group, CK-MB, NT-proBNP, S100β, Copeptin in the poor prognosis group increased, and the BIS value decreased (P<0.05). In the poor prognosis group, CK-MB, NT-proBNP, S100β, and Copeptin at 72 hours after admission were all lower than those at 24 hours after admission, and the BIS value was higher than that at 24 hours after admission (P<0.05). Logistic regression analysis showed that ASCMP patients with increased S100β, Copeptin, and decreased BIS values had an increased risk of adverse events (P<0.05). The ROC curve showed that the area under the curve of the combined detection of BIS, S100β and Copeptin was 0.859, which had a great predictive value for the prognosis of ASCMP patients. Conclusion: BIS, S100β combined with Copeptin detection is of great value for early assessment of ASCMP disease and prognosis prediction.

Anti-mycobacterial activity of two natural Bisanthraquinones: (+)-1,1′-Bislunatin and (+)-2,2′-Epicytoskyrin A

Tuberculosis is considered one of the leading death causes in the world by a single infectious agent, Mycobacterium tuberculosis (Mtb). The search for a new biologically active compound for the treatment of Tuberculosis is an urgent need due to the rise of multidrug-resistant phenomena. Endophytic fungi were known for a vast reservoir for bioactive secondary metabolites. Endophytic fungi, Diaporthe sp. GNBP-10 associated with gambier plant Uncaria gambier Roxb was able to produce two natural bisantharaquinone, (+)-1,1’-Bislunatin (Bis) and (+)-2,2’-Epicytoskyrin A (Epi), possessing strong antibacterial activities against the various pathogen. In this study, the biological activity screening of (Bis) and (Epi) will be extended by evaluating their activity against Mtb H37Rv. The in-vitro assay was conducted via determination of Minimum Inhibitory Concentration (MIC), nutrient-starvation Mtb, Biofilm Mtb formation, and Mtb-infected macrophage assay. Meanwhile, the in-silico screening was done by docking and Adsorption, Distribution, Metabolism, and Exertion (ADME) studies. Bis and Epi showed promising anti-tubercular activity, as shown by the MIC value of Bis, which is the same as rifampicin (standard drug) at 0.422 μM. Meanwhile, Epi carried out the same MIC value as isoniazid (standard drug) at 0.844 μM. Further investigation on in-vitro assay resulted in Epi and Bis, which were observed for having the ability to combat nutrient-starvation and biofilm of the Mtb model with relatively moderate activity in bacterial reduction with log reduction between 1-2 folds. The cytotoxicity study revealed that Bis possessed high toxicity at all tested concentrations, while the toxicity of Epi decreased as the tested concentrations decreased. Both compounds could reduce the number of Mtb infected into macrophages in 2 folds log reduction. The in-silico result via docking study shows that both compounds have good affinity with pantothenate kinase (PanK) enzyme with a glide score of -8.427 kcal/mol and -7.481 kcal/mol for Epi and Bis, respectively. This study suggests that Epi displayed a potency to be developed further as an anti-mycobacterial compound as it is shown by in-vitro assay, cytotoxicity, and in-silico study. Despite possessing good anti-mycobacterial activity, further studies such as QSAR (Quantitative-Structure Activity Relationship) is needed to improve the physicochemical properties of Epi while maintaining its biological properties.

Effects of continuous endotracheal-laryngopharynx topical anesthesia on the general anesthetic requirements during surgery.

The purpose of this study was to investigate the general anesthetic requirements in patients with continuous endotracheal-laryngopharynx topical anesthesia using medicine injecting endotracheal tube during surgery. A total of 78 patients with American Society of Anesthesiologists (ASA) physical status I–II were randomly divided into test group and control group. After anesthesia, patients were injected by 1.5 mL of 1% Tetracaine for topical anesthesia, and later injected similarly at hourly intervals during surgery while patients in control group were non-injected. There was no statistical significance in values of SBP, DBP, MAP, HR and plasma concentrations of E, NE and Cor at same time point between the two groups during operation (P>0.05). There was no statistical significance in value of BIS at T0-T5 between the two groups (P>0.05). However, value of BIS at T6 in test group was significantly higher than that in control group (69.7±2.1 vs. 58.6±2.3, P<0.01). Doses of sevoflurane, propofol sufentanil and cisatracurium used up in test group decreased by 12.3% (P<0.01); 12.7% (P<0.01); 14.5% (P<0.01) and 4.9% (P>0.05) than those in control group, respectively. Continuous endotracheal-laryngopharynx topical anesthesia using 1% Tetracaine via medicine-injecting endotracheal tube can significantly decrease general anesthetic requirements of surgery.

Does the selection of sedative in transcatheter aortic valve implantation influence the extent of hypercapnia leading to elevated pulmonary artery pressure?

Introduction Local anesthesia with sedation has recently become a common technique in transfemoral transcatheter aortic valve implantation (TF-TAVI) in patients with aortic stenosis. This retrospective study was performed to compare the influence of different sedating drugs on arterial carbon dioxide pressure and pulmonary artery pressure (PAP). Methods Thirty patients who underwent TF-TAVI under monitored anesthesia care from April 2018 to April 2019 were enrolled in this study. The subjects were divided into one of two groups; dexmedetomidine (D) group and propofol (P) group. A pulmonary artery catheter was inserted in all patients. The blood gas data, systemic blood pressure, pulmonary artery pressure, the value of BIS and spectral edge frequency 95 (SEF 95) before sedation and just after administering heparin were collected for analysis. The % change of PaCO2, mean PAP and mean pulmonary arterial pressure to mean systemic arterial pressure ratio (Pp/Ps) were calculated. The statistical analysis were performed using Mann-Whitney U-test. Results The median values of BIS and SEF 95 were not significantly different between groups. The % change of PaCO2 was significantly higher in group P (36.7 [28.6-45.1] % vs 14.0 [9.2-22.6] %[median (inter-quartile range)]; p Discussion Our results showed a significant elevation of PaCO2 and Pp/Ps in group P. These findings indicate that propofol may be disadvantageous for performing TAVI under sedation from the aspect of hypercapnia and consequent elevation of pulmonary vascular resistance.

Mass bias evolution in tSZ cluster cosmology

Galaxy clusters observed through the thermal Sunyaev–Zeldovich (tSZ) effect are a recent cosmological probe. The precision on the cosmological constraints is affected mainly by the current knowledge of cluster physics, which enters the analysis through the scaling relations. Here we aim to study one of the most important sources of systematic uncertainties, the mass bias,b. We have analysed the effects of a mass-redshift dependence, adopting a power-law parametrisation. We applied this parametrisation to the combination of tSZ number counts and power spectrum, finding a hint of redshift dependence that leads to a decreasing value of the mass bias for higher redshift. We tested the robustness of our results for different mass bias calibrations and a discrete redshift dependence. We find our results to be dependent on the clusters sample that we are considering, in particular obtaining an inverse (decreasing) redshift dependence when neglectingz &lt; 0.2 clusters. We analysed the effects of this parametrisation on the combination of cosmic microwave background (CMB) primary anisotropies and tSZ galaxy clusters. We find a preferred constant value of mass bias, having (1 − b) = 0.62 ± 0.05. The corresponding value ofbis too high with respect to weak lensing and numerical simulations estimations. Therefore we conclude that this mass-redshift parametrisation does not help in solving the remaining discrepancy between CMB and tSZ clusters observations.

The impact of bispectral index-guided anesthesia on the incidence of postoperative delirium in elderly patients with chronic anemia

Objective Discuss the influence of BIS monitoring on the incidence of postoperative delirium(POD) in elderly patients with chronic anemia. Methods One hundred and eighty cases of elective surgery under general anesthesia were randomly divided into BIS monitoring group and control group(n=90), the control group using routine anesthesia, and BIS monitoring group maintaining the value of BIS between 40-60 during anesthesia. The hemodynamic indexes were monitored after entering the operation room(T0), after anesthesia(T1), immediate intubation(T2), 3 min after intubation(T3), cut the skin(T4), 1 h during operation(T5), the end of operation(T6). Observe the dose of propofol during anesthesia, surgery time, extubation time, recovery time and the occurrence of POD in patients. Results The overall incidence of BIS monitoring group delirium was 17.5%, lower than 31.2% in the control group(P< 0.05), the incidence of delirium on the first day of 13.3% was significantly lower than 28.9% in the control group(P<0.05), the incidence of 5.6% in the second day also lower than 14.4% in the control group(P<0.05), and duration of delirium was significantly lower than the control group (P<0.05). The extubation time[(26±8) min] and hospital stays[(11.5±2.3) d] of BIS monitoring group were significantly earlier than[(41 ± 12) min and (12.6 ± 4.4) d] control group, the difference was statistically significant(P<0.05). Conclusions BIS monitored anesthesia reduces the incidence of POD and reduces the duration of delirium in elderly patients with chronic anemia. Key words: Bispectral index; Elderly; Anemia; Postoperative delirium

Influence of neuromuscular block and reversal on bispectral index and NeuroSense values

Influence of neuromuscular block and reversal on bispectral index and NeuroSense values

Efficacy of intravenous midazolam versus clonidine as premedicants on bispectral index guided propofol induction of anesthesia in laparoscopic cholecystectomy: A randomized control trial.

Background:Midazolam and clonidine are preferred premedicants whose effects are not restricted to the preoperative period. In addition, these premedicants significantly modulate not only the intraoperative requirements of the anesthetic agents, but also the postoperative outcome. We aim to compare the efficacy of both the agents in view of premedication, induction characteristics, hemodynamic changes and postoperative complications utilizing bispectral index (BIS) using propofol anesthesia.Materials and Methods:The type of this study was randomized control trial conducted on patients undergoing laparoscopic cholecystectomy under general anesthesia with endotracheal intubation. Study included 105 patients of either sex aged 20-60 years. The patients were randomly allocated into three groups: Intravenous midazolam (Group 1), clonidine (Group 2), and normal saline (Group 3) (control). The initial value of BIS and Ramsay Sedation Score, dose of propofol required for induction were noted in each group and monitored for pulse rate, electrocardiograph, noninvasive blood pressure, and BIS.Results:The requirement of propofol ranged from 40 to 150 mg. Mean requirement was maximum in Group 3 (109.43 ± 20.14 mg) and it was minimum in Group 1 (78.57 ± 22.15 mg). A significant reduction in consumption of propofol with the use of midazolam (P < 0.001) and clonidine (P < 0.001) was observed. Both premedicants partially attenuates laryngoscoy and intubation response along with reduction in the incidence of postoperative complications.Conclusion:Both clonidine and midazolam contributed equally in lowering propofol consumption. Reduction in the induction dosage of propofol and hemodynamic variations were also observed to be similar with the use of midazolam or clonidine as premedicants. Both provide a beneficial effect in relation to recovery and less postoperative complications. However clonidine premedication was found to be more effective in preventing post operative shivering and can be recommended in routine practice.

Efficacy of Bispectral Index Monitoring During Balanced Propofol Sedation for Colonoscopy: A Prospective, Randomized Controlled Trial

Appropriate use of propofol is necessary, and objective monitoring of sedation with propofol may be helpful. Studies on the efficacy of bispectral index (BIS) monitoring in deep sedation have been conducted, but its efficacy in colonoscopy with moderate sedation is unknown. In this study, the efficacy of BIS monitoring during colonoscopy with moderate level sedation via balanced propofol sedation was investigated. To determine the cut-off value of BIS before the test, an optimal BIS value was determined. Patients who were scheduled to undergo outpatient colonoscopy were prospectively randomized to either a BIS or control group. Finally, a total of 115 patients were selected for this study. The satisfaction level, the complication, and the dosage of the administered propofol were compared. The BIS values and the modified observer's assessment of alertness/sedation scores (MOAA/S) were positively correlated (r=0.66 and p<0.001). The optimal cut-off value of BIS for maintaining moderate sedation was 81, and the area under the ROC curve was 0.88 (95% CI 0.82-0.93), indicating high prediction accuracy. However, there was no difference between the BIS group and the control group in levels of satisfaction of either patients or endoscopists. In addition, there was no difference in the complication and the required dose of propofol between both groups. BIS and clinical sedation scores, MOAA/S scores, showed a high level of correlation. However, no significant efficacy was observed in the BIS group who underwent outpatient colonoscopy.

Clinical vs. bispectral index-guided propofol induction of anesthesia: A comparative study

Background:Clinically optimized focusing of drug administration to specific need of patient with bispectral index (BIS) monitoring results in reduced dose and faster recovery of consciousness. This study was planned with an aim to study and compare the conventional clinical end point or BIS on the requirement of dosage of propofol, hemodynamic effects, and BIS alterations following propofol induction.Methods:70 patients, ASA I and II, 20-60 years undergoing elective surgical procedure under general anesthesia with endotracheal intubation were selected and divided into two groups. Group A received (inj.) fentanyl (2 μg/kg), followed 3 min later by inj. propofol at the rate of 30 mg/kg/hr infusion till the loss of response to verbal command while group B received inj. fentanyl (2 μg/kg), followed 3 min later by inj. propofol at the rate of 30 mg/kg/hr infusion. The end point of hypnosis was when the BIS value was sustained for 1 min at 48±2. The patients were intubated. Total induction dose of propofol was noted in each group. The value of BIS and hemodynamic parameters (heart rate, systolic/diastolic blood pressure) were noted at the time of loss of consciousness, at the time of intubation, and 1 min after intubation, thereafter every minute for first 10 min and thereafter every 10 min till end of surgery. Any involuntary muscle activity such as jerky movements, dystonic posturing, and opisthotonos were also recorded.Results:The mean dose of propofol used in groups A and B were 1.85±0.48 mg/kg and 1.79±0.41 mg/kg, respectively. The dosage used in group B were less but not clinically significant (P=0.575). On comparing the dosage of propofol in males among the groups there was a significantly lower dosage of propofol required in group B (2.06±0.45 mg/kg and 1.83±0.32 mg/kg, respectively, P=0.016). This decrease however was not seen in female patients dosage being 1.65±0.44 mg/kg and 1.75±0.49 mg/kg, respectively (P=0.372). The hemodynamic variables including heart rate, systolic/diastolic blood pressure and BIS were comparable within the group at induction, post-induction, and intubation. However, there was a significant increase in all the parameters at postintubation readings (P<0.001).Conclusion:No significant difference in the induction dose of propofol was observed when assessed clinically (loss of verbal response) or by BIS monitoring. Traditional teaching to titrate the dose of propofol and depth of anesthesia during intubation by loss of verbal response is as good as BIS value monitoring.

Clinical sedation and bispectral index in burn children receiving gamma‐hydroxybutyrate

Gamma-hydroxybutyrate (GHB) may be an interesting hypnotic agent in burn patients because of its good respiratory or hemodynamic tolerance. However, its clinical and electroencephalographic (EEG) sedative effects are not yet described in children. The aim of this prospective and randomized study was to assess clinical and EEG effects of increasing intravenous (IV) doses of GHB in burn children requiring sedation for burn wound cares. Thirty six children hospitalized in a burn care unit were included and randomly assigned into three groups (G) according to the single IV dose of GHB they received before burn wound care: 10 mg · kg(-1) in G10, 25 mg · kg(-1) in G25, or 50 mg · kg(-1) in G50. All patients received oral premedication (morphine and hydroxyzine) 30 min before GHB injection. Respiratory rate, heart rate, pulse oximetry, and bispectral index (BIS) were continuously monitored. Depth of sedation was clinically assessed using Observer's Assessment of Alertness and Sedation (OAAS) Score, every 2 min until recovery (i.e., OAAS = 4). Median age was 17.5 [12-34] months. Whatever the dose, BIS decreased after IV GHB. Nadir value of BIS was significantly lower in G25 and G50 than in G10, as was for OAAS score. Nadir values were reached after same delays in G25 and G50. Duration of sedation was dose-dependent. Bispectral index decreased after GHB injection and was correlated with OAAS score. Deep sedation can be safely achieved with IV doses of 25 or 50 mg · kg(-1), but the last dose was associated with prolonged duration of clinical sedation.

Bilateral Bispectral Index (BIS)-VISTA monitoring of cerebral hypoperfusion in patients with carotid artery stenosis undergoing coronary artery bypass surgery

BackgroundCarotid stenosis is a frequent coexisting condition in patients undergoing Coronary Artery Bypass Graft (CABG) surgery. During cardiac surgery, acute hemodynamic changes can cause cerebral ischemia. When acute slowing of the Electroencephalography (EEG) develops because of cerebral ischemia, a profound reduction in Bispectral Index (BIS) is seen, although the depth of anesthesia does not change. We investigated the diagnostic value of bilateral BIS as an indicator of cerebral hypoperfusion during CABG surgery in patients with carotid artery stenosis and the incidence of left-right BIS differences.MethodsForty patients scheduled for elective CABG surgery were randomized into two groups according to preoperative Duplex carotid ultrasound; Group with Carotid Artery stenosis (CA-stenosis) (n = 23) and Group without stenosis (CA-normal) (n = 17). All patients underwent monitoring using bilateral BIS system. We analyzed BIS data at eight stages of the CABG procedure.ResultsMean BIS values recorded from left and right hemispheres declined significantly in comparison to steady state of anesthesia in both groups (T2), (p < 0.0001 for both). In CA-stenosis group only, there were significant interhemispheric differences during AXC apply (p < 0.01). Average BIS values of right and left hemispheres and parallel to it, SEF data decreased significantly in both groups during initiation of CPB-T3, during AXC application-T4 and during AXC removal-T6 (p < 0.001). Intergroup comparison showed significant decrease in BIS values in CA-stenosis group when compared to CA-normal group during induction of anesthesia-T1 and during AXC apply-T4 (both p < 0.001) and during AXC removal-T6 (p = 0.04).ConclusionOur findings suggest that an acute decrease in BIS which represent abrupt slowing of the EEG, reflects acute cerebral hypoperfusion particularly when it accompanies acute hypotension, as long as the changes in BIS is not drug induced.

High-Performance Electron-Transporting Polymers Derived from a Heteroaryl Bis(trifluoroborate)

In this communication, we report that dipotassium aryl bis(trifluoroborate)s make stable and easy-to-purify yet reactive monomers under Suzuki polycondensation reactions. A bis(trifluoroborate) of 2-alkylbenzotriazole was prepared successfully and copolymerized with dibromobenzothiadiazole in the presence of a Pd catalyst and LiOH, yielding high molecular weight conjugated polymers. This polymer (P1) composed of all electron-accepting units shows excellent electron-transport properties (μ(e) = 0.02 cm(2) V(-1) s(-1)), which proves the value of the aryl bis(trifluoroborate) monomers and suggests that many other types of semiconducting polymers that could not be accessed previously can be synthesized using this approach.

Changes in BiSpecteral Index (BiS) values during cardiopulmonary bypass (CPB)

Background: BiSpecteral Index (BiS) monitoring is standard monitoring regimen in anaesthesia practice. It has also been used in cardiac surgery. It is especially important due to the high incidence of neurological injury or dysfunction that occurs following CPB. This is a retrospective study of 33 cases that were monitored with BiS during the course of coronary artery or valvular surgery, including the period of CPB. Methods: Thirty three cases monitored with BiS were studied retrospectively. Result: From the recordings it was determined that the value of BiS which was ranging between 40 to 60 after induction, dropped below 25 at the onset of CPB. This change was statistically significant (p<0.05). Conclusion: This decrease in the BiS value is probably a result of hypo-perfusion and due to clear, oxygen - poor priming fluid reaching the brain. Other periods of hypotension also correlated with the low values of BiS. This cerebral hypoxia which would occur at this time could be the cause of the incidence of neurological dysfunction that is known to occur following CPB.

Period Lengths for Iterated Functions

Let Ωnbe thenn-element set consisting of all functions that have {1, 2, 3, . . .,n} as both domain and codomain. LetT(f) be the order off,i.e., the period of the sequencef,f(2),f(3),f(4). . . of compositional iterates. A closely related number,B(f) = the product of the lengths of the cycles off, has previously been used as an approximation forT. This paper proves that the average values of these two quantities are quite different. The expected value ofTiswherek0is a complicated but explicitly defined constant that is approximately 3.36. The expected value ofBis much larger:

Environmental modulation of metabolic allometry in ornate rainbowfishRhadinocentrus ornatus

The nature of the relationship between the metabolic rate (MR) and body mass (M) of animals has been the source of controversy for over seven decades, with much of the focus on the value of the scaling exponent b, where MR is proportional to M(b). While it is well known that MR does not generally scale isometrically (i.e. b is seldom equal to 1), the value of b remains the subject of heated debate. In the present study, we examine the influence of an ecologically relevant abiotic variable, pH, on the metabolic allometry of an Australian freshwater fish, Rhadinocentrus ornatus. We show that the value of b is lower for rainbowfish acclimated to acidic (pH 5.0) conditions compared to rainbowfish acclimated to alkaline conditions (pH 8.5), but that acute exposure to altered pH does not alter the value of b. This significant effect of an abiotic variable on metabolic allometry supports a growing body of evidence that there is no universal value of b and demonstrates that experimental manipulations of metabolic allometry represent powerful, and as yet underused, tools to understand the factors that constrain and influence the allometry of metabolic rate.

Maternal and neonatal effects of sevoflurane and desflurane in cesarean section

Background: This study was designed to compare the maternal and neonatal effects of two volatile anesthetic agents, sevoflurane and desflurane during general anesthesia for cesarean section. Methods: Sixty patients undergoing cesarean section were randomly selected and divided into two groups. After induction, sevoflurane (Group S, n = 30) and desflurane (Group D, n = 30) were administered to achieve steady-state end-tidal concentration of 1 vol% and 3 vol%, respectively. The maternal outcomes were evaluated at various time points in terms of hemodynamic changes and bispectral index (BIS). The neonatal characteristics were descripted with Apgar score and umbilical blood gas analysis. Results: The BIS was lower in Group D than in Group S at 5 and 7 minutes after intubation and at delivery (P ＜ 0.05). The value of BIS is between 40 to 60 in Group D appropriated with anesthetic depth during surgery. Other parameters as well as neonatal outcomes were not different between two groups. Intraoperative awareness of patients were not present at all. Conclusions: Maternal and neonatal effects were not significantly different between two groups and no adverse effects were seen. Despite of BIS over 60 at some period, maternal recall during surgery were absent postoperatively. Therefore, not only sevoflurane but also desflurane can be used for safe and effective anesthesia in cesarean section.

Diagnostic and prognostic use of bispectral index in coma, vegetative state and related disorders

Primary objective: This study investigates (1) the utility of the bispectral index (BIS) to distinguish levels of consciousness in severely brain damaged patients and, particularly, disentangle vegetative state (VS) from minimally conscious state (MCS), as compared to other EEG parameters; (2) the prognostic value of BIS with regards to recovery after 1 year.Research design: Multi-centric prospective study.Method and procedures: Unsedated patients recovering from coma were followed until death or transferal. Automated electrophysiological and standardized behavioural assessments were carried out twice a week. EEG recordings were categorized according to level of consciousness (coma, VS, MCS and Exit MCS). Outcome was assessed at 1 year post-insult.Main outcomes and results: One hundred and fifty-six EEG epochs obtained in 43 patients were included in the analyses. BIS showed a higher correlation with behavioural scales as compared to other EEG parameters. Moreover, BIS values differentiated levels of consciousness and distinguished VS from MCS while other EEG parameters did not. Finally, higher BIS values were found in patients who recovered at 1 year post-insult as compared to patients who did not recover.Conclusion: EEG-BIS recording is an interesting additional method to help in the diagnosis as well as in the prognosis of severely brain injured patients recovering from coma.

Correlation Of Bispectral Index With Glasgow Coma Score In Mild And Moderate Head Injuries

Bispectral Index (BIS) derived from electroencephalogram (EEG) is primarily developed to monitor the depth of unconsciousness. Recent evidence suggests that BIS may also help in the detection of cerebral ischemia and prognostication of outcome of traumatic brain injury (TBI). The present study was designed to investigate the correlation between Glasgow Coma Score (GCS) and BIS in mild and moderate head injury. In 29 patients with mild (GCS 13-15) and moderate (GCS 9-12) head injuries who underwent craniotomy, GCS and BIS were measured before surgery, after surgery and once a day for the first 10 days. A significant correlation was found between GCS and BIS in the data sets from all the patients (r = 0.67; p < 0.001). Mean BIS values increased with increasing GCS scores. However, the scatter of BIS values for any GCS score was high limiting the value of BIS in predicting GCS. Mean BIS values were significantly different between mild and moderate head injuries [65.7 +/- 16.1 vs. 85.7 +/- 6.1, p = 0.006]. In patients with mild and moderate head injury, significant correlation exists between GCS and BIS. But the high degree of scatter of BIS values for any given GCS score limits its use as a monitor of depth of coma in TBI. Further studies are required to understand the relation between BIS algorithm and cerebral electrical activity following TBI to define the role of BIS as an electrophysiological correlate of consciousness in TBI.