Mean BIS Research Articles

Correlation between the Observer's Assessment of Alertness/Sedation score and bispectral index in patients receiving propofol titration during general anesthesia induction.

To explore the relationship between the Observer's Assessment of Alertness/Sedation (OAAS) score and the bispectral index (BIS) during propofol titration for general anesthesia induction and analyze the impact of BIS monitoring delay on anesthetic depth assessment. This study was conducted among 90 patients (ASA class I-II) undergoing elective surgery under general anesthesia. For anesthesia induction, the patients received propofol titration at the rate of 0.5 mg·kg-1·min-1 till OAAS scores of 4, 3, 2, and 1 were reached. After achieving an OAAS score of 1, remifentanil (2 μg·kg⁻¹) and rocuronium (0.6 mg·kg⁻¹) were administered, and tracheal intubation was performed 2 min later. BIS values, mean arterial pressure (MAP), heart rate (HR), and propofol dosage at each OAAS score were recorded, and the correlation between OAAS scores and BIS values was analyzed. The diagnostic performance of BIS values for determining when the OAAS score reaches 1 was analyzed using ROC curve. All the patients successfully completed tracheal intubation. BIS values of the patients at each of the OAAS scores differed significantly (P<0.01), and the mean BIS value decreased by 4.08, 8.32, 5.43 and 5.24 as the OAAS score decreased from 5 to 4, from 4 to 3, from 3 to 2, and from 2 to 1, respectively. There was a significant correlation between the OAAS score and BIS values (ρ=0.775, P<0.001). The median BIS value for an OAAS score of 1 was 76, at which point 83.33% of the patients had BIS values exceeding 60. ROC curve analysis showed that for determining an OAAS score of 1, BIS value, at the optimal cutoff value of 84, had a sensitivity of 88.9%, a specificity of 73.3%, and an area under the curve of 0.842 (0.803-0.881). OAAS score during induction of general anesthesia is strongly correlated with BIS value and is a highly sensitive and timely indicator to compensate for the delay in BIS monitoring.

COMPARATIVE STUDY OF PROPOFOL AUTO-COINDUCTION VERSUS KETAMINE PROPOFOL COINDUCTION USING PRIMING PRINCIPLE BY BISPECTRAL INDEX ANALYSIS FOR DAY CARE SURGERY

Aim:The aim of our study was to do the comparison of Propofol Auto-coinduction versus Ketamine Propofol coinduction using priming principle by bispectral index analysis for day care surgery. Methods:150 patients participated in our study at Govt. Medical College and Rajindra Hospital, Patiala. Patients aged above 18 years and ASA Grade I and II scheduled to undergo elective surgery were included in this prospective, randomized controlled trial. All patients were randomly assigned into 3 groups of 50 each. Group A- patients were given Propofol 0.5mg/kg body wt., Group B- patients were given Ketamine 0.5mg/kg body wt., Group C- patients were given normal saline 2.5ml 2 minutes before induction. Patients were induced with injection Propofol 1% at rate of 30mg/10 sec until BIS value reaches to 40. Induction dose requirements of Propofol, Haemodynamic parameters including HR, MAP, SBP, DBP,SPO2, ECG, RR were recorded. Incidence of post op complications / side effects were also recorded. Data was tabulated and subjected to statistical analysis. Results: Groups were comparable to each other with respect to age, weight, gender, ASA status. Significant difference was found in HR, SBP, DBP between Group A and Group B at 1 minute and 2 minute after coinduction. MAP shows statistically highly significant (p &lt; 0.001) results after 1minute and 2 minute of coinduction. Total dose of propofol required and mean BIS value shows highly significant results when compared between groups. Conclusion: In conclusion, our study identified that overall dosage of propofol was significantly lower when modest doses of propofol and ketamine were given beforehand than when a placebo was used. When used as an induction agent, ketamine offers better haemodynamic stability.

Examining the Relationship Between Functioning and Spiritual Well-Being in Female Patients Diagnosed with Bipolar Disorder

Aim: The aim of this study is to examine the relationship between functionality and spiritual well-being in female patients diagnosed with bipolar disorder. Methods: The research was conducted in a descriptive and correlational study. The research was conducted with 61 female bipolar patients who applied to the psychiatric outpatient clinic of a hospital in eastern Turkey between January 2023 and January 2024. Personal Information Form, Bipolar Disorder Functioning Scale (BIDS) and Spiritual Well-Being Scale (FACIT-Sp-12) were used to collect research data. In evaluating research data; Number, mean, percentage distributions, standard deviation and Pearson correlation analyzes were used. Results: It was found that the research participants' mean BIS total score was 96.21±20.02, and the FACIT-Sp-12 total score mean was 31.26±9.35. It was determined that there was a positive, statistically significant relationship between the functionality and spiritual well-being score averages of female patients diagnosed with bipolar disorder. Conclusion: It was determined that the functionality of female patients diagnosed with bipolar disorder was at an average level, and their spiritual well-being levels were above average. It was determined that there was a relationship between the functionality and spiritual well-being of female patients diagnosed with bipolar disorder.

Efficacy of Ultrasound-Guided Intercostal Nerve Block on Pain Management and Physiological Outcomes in Breast Cancer Mastectomy: A retrospective study.

To evaluate the efficacy of ultrasound-guided intercostal nerve block in managing pain and physiological responses in patients undergoing radical mastectomy for breast cancer. A retrospective study analyzed 120 patients scheduled to undergo radical mastectomy in our hospital between January 2022 and December 2023. Depending on the type of anesthesia received, participants were assigned to the experimental group (60 patients) to receive ultrasound-guided intercostal nerve block and intravenous general anesthesia, or the control group (60 patients) to receive intravenous general anesthesia only. Both groups will utilize patient-controlled intravenous analgesia (PCIA) postoperatively. We will monitor and compare hemodynamic parameters, SpO2, and bispectral index (BIS) at multiple time points, and assess postoperative pain, inflammatory markers, PCIA utilization, and adverse reaction incidence. Comparative analysis showed distinct trends in heart rate, mean arterial pressure (MAP), BIS, and SpO2 across various surgical stages between groups. Notably, MAP values were consistently higher and less variable in the experimental group during surgery (P < .05). Pain assessments at 4, 12, and 24 hours postoperatively in both quiet and coughing states revealed significantly milder pain in the experimental group (P < .05). Preoperative inflammatory markers (PGE2, TNF-α, IL-6, MCP-1) were similar between groups; however, 24 hours post-surgery, the experimental group showed significantly lower levels of PGE2, IL-6, and MCP-1 (P < .05). Sufentanil consumption during surgery and PCIA use were notably lower in the experimental group (P < .05). The experimental group also experienced fewer anesthesia-related adverse reactions (8.33%) compared to the control group (25.00%) (P < .05). Ultrasound-guided intercostal nerve block significantly improves hemodynamic stability, reduces postoperative inflammatory markers, lowers the need for sufentanil, and minimizes adverse reactions in patients undergoing radical mastectomy for breast cancer.

Monitored Anesthesia Care in Minimally Invasive Spine Surgery-A Retrospective Case Series Study.

Background and Objectives: Minimally invasive spine surgery (MISS) under monitored anesthesia care (MAC) has emerged as a treatment modality for spinal radiculopathy. It is essential to secure the airway and guarantee spontaneous respiration without endotracheal intubation during MISS in a prone position. Materials and Methods: To evaluate the feasibility and safety of MAC with dexmedetomidine during MISS, we retrospectively reviewed clinical cases. A retrospective review of medical records was conducted between September 2015 and June 2016. A total of 17 patients undergoing MISS were included. Vital signs were analyzed every 15 min. The depth of sedation was assessed using the bispectral index (BIS) and the frequency of rescue sedatives. Adverse events during anesthesia, including bradycardia, hypotension, respiratory depression, postoperative nausea, and vomiting, were evaluated. Results: All cases were completed without the occurrence of airway-related complications. None of the patients needed conversion to general anesthesia. The median maintenance dosage of dexmedetomidine for adequate sedation was 0.40 (IQR 0.40-0.60) mcg/kg/hr with a median loading dose of 0.70 (IQR 0.67-0.82) mcg/kg. The mean BIS during the main procedure was 76.46 ± 10.75. Rescue sedatives were administered in four cases (23.6%) with a mean of 1.5 mg intravenous midazolam. After dexmedetomidine administration, hypotension and bradycardia developed in six (35.3%) and three (17.6%) of the seventeen patients, respectively. Conclusions: MAC using dexmedetomidine is a feasible anesthetic method for MISS in a prone position. Hypotension and bradycardia should be monitored carefully during dexmedetomidine administration.

Influence of (S)-Ketamine on the Bispectral Index and Electroencephalogram during Total Intravenous Anesthesia: A Randomized Clinical Trial

Background: This study aims to evaluate the influence of different doses of (S)-ketamine on bispectral index (BIS) and electromyographic power (pEMG). Method: Forty participants, submitted to controlled venous effector site anesthesia, were randomly distributed into 5 groups. In the k0 control group, participants did not receive (S)-ketamine; k1, k2, k3, and k4 received (S)-ketamine 200 µg.kg-1 iv followed by a continuous infusion of 100, 200, 300, and 400 µg.kg-1 h-1, respectively. In each group, 11 moments were evaluated: M0, before anesthetic induction, M1, 10 minutes after anesthesia stabilization with BIS between 45 and 55, and M2 to M10, 3, 6, 9, 12, 15, 18, 21, 24, and 27 minutes after (S)-ketamine. At all moments, BIS and pEMG values were recorded. An ANOVA was used for repeated measures, and the p-value was adjusted for multiple comparisons by Tukey’s test, considering p&lt; 0.05 as significant. Results: No significant changes (p&gt; 0.05) were observed at each moment after M0 by comparing the mean BIS and pEMG values between all groups. Conclusion: Electroencephalographic parameters (BIS and pEMG) are not significantly influenced when this (S)-ketamine infusion model and total intravenous anesthesia are performed.

Impulsivity and cannabis use disorder among tunisian sample

IntroductionIn the past few years, there has been a considerable amount of evidence that cannabis use can cause structural and functional brain abnormalities.Structural imaging studies of cannabis users have revealed reduced prefrontal cortex volumes and white matter damage that may be involved with impulsivity. Objectives: To Determine the level of dependence on cannabis among cannabis users consulting the detoxification center of Sfax, Tunisia To assess in addition the impact of cannabis on impulsivity and motor control.MethodsThis is a cross-sectional, descriptive and analytical study that was conducted over a period of 13 months between September 15, 2020 and October 1, 2021 among cannabis users consulting the detoxification center of Sfax, Tunisia.A short form of the Barratt Impulsiveness Scale (the BIS-15) and a Cannabis Abuse Screening Test (CAST) were used to assess impulsivity and to determine cannabis abuse. Results: Thirty Eight cannabis users agreed to participate in this study. The distribution of CAST scores showed that 36 users (94.7%) had problematic cannabis use at the time of the study. The mean BIS 15 score was 38.2. In our sample, The level of impulsivity was highest in people with a high level of cannabis dependence. A higher level of impulsivity was found in younger subjects. However, a greater level of impulsivity was found in subjects with a lower socio-economic level. Concerning employment status, unemployment was significantly correlated with a higher level of impulsivity.ConclusionsImpulsivity is often associated with a variety of problematic behaviors such as aggressive behavior, smoking, drug abuse, pathological gambling or compulsive buying.A higher frequency of cannabis use and earlier age of onset use have been shown to be associated with the highest rates of impulsivity.Therefore, cannabis addiction represents a real public health problem, both because of the serious complications and heavy repercussions that it causes.Disclosure of InterestNone Declared

Effect of Change of Position (Supine vs. Steep Trendelenburg) on Bispectral Index Value During Robotic Surgery.

Background: Bispectral Index (BIS) is used to monitor anesthetic depth and is a useful instrument to keep a check on intraoperative awareness. But there are various situations in which it shows false readings. Our aim of the study was to observe the changes in BIS value with steep Trendelenburg position, which is usually done, in robotic pelvic surgeries.Methods: We included 100 patients in our study who underwent robotic prostatectomies and hysterectomies. After anesthetizing the patient, the patient's heart rate, systolic blood pressure, mean arterial pressure, end-tidal desflurane, end-tidal CO2, and BISwere recorded at three min. intervals, for 15 minutes before and 15 minutes after the Trendelenburg position without surgical stimulus.Results: We found a significant increase in BIS values (p <0.05) after the change of position from supine to steep Trendelenburg. Heart rate, systolic blood pressure, and mean arterial pressure were almost constant.Conclusion: Our study concluded that the BIS value increases when patients were shifted from the supine to Trendelenburg position, which might raise the concern of a decrease in anesthetic depth.

Usefulness of bispectral index and patient state index during sevoflurane anesthesia in children: A prospective observational study.

Cortical electroencephalography-based devices are used to monitor the depth of anesthesia. In this study, we evaluated the values of bispectral index (BIS) and patient state index (PSI) during sevoflurane anesthesia in children. The ability/accuracy of BIS and PSI to predict the maintenance and recovery state of anesthesia was evaluated based on prediction probability (Pk) values and the secondary outcomes were agreement and correlation of 2 monitors.Fifty children (3–12 years old) were enrolled and the patients received sevoflurane anesthesia with remifentanil followed by propofol administration. Before the induction of anesthesia, BIS and PSI sensors were simultaneously placed on the forehead, and data were collected until the end of anesthesia. Maintenance state was defined as the period following intubation until the cessation of sevoflurane, while recovery state was defined as the period following the cessation of sevoflurane until awake. Pk, agreement or correlation of BIS and PSI in different anesthesia state were calculated.Anesthesia reduced mean BIS and PSI values. Pk of BIS (95% confidential interval [CI]: 0.78–0.91) and PSI (95% CI: 0.82–0.91) for anesthesia were 0.85 and 0.87, respectively. Agreement was 0.79 for recovery state and 0.73 for maintenance state. Pk values were comparable for BIS and PSI.Agreement between BIS and PSI measurements in the same state was relatively good. Therefore, these monitors are appropriate for monitoring for different state of anesthesia in pediatric population.

Índice biespectral y tasa de supresión tras parada cardiaca: ¿son útiles para individualizar planes de escalada terapéutica?

Introduction and objectivesMyocardial dysfunction contributes to early mortality (24-72 hours) among survivors of a cardiac arrest (CA). The benefits of mechanical support in refractory shock should be balanced against the patient's potential for neurological recovery. To date, these early treatment decisions have been taken based on limited information leading mainly to undertreatment. Therefore, there is a need for early, reliable, accessible, and simple tools that offer information on the possibilities of neurological improvement. MethodsWe collected data from bispectral index (BIS) and suppression ratio (SR) monitoring of adult comatose survivors of CA managed with targeted temperature management (TTM). Neurological status was assessed according to the Cerebral Performance Category (CPC) scale. ResultsWe included 340 patients. At the first full neurological evaluation, 211 patients (62.1%) achieved good outcome or CPC 1-2. Mean BIS values were significantly higher and median SR lower in patients with CPC 1-2. An average BIS> 26 during first 12hours of TTM predicted good outcome with 89.5% sensitivity and 75.8% specificity (AUC of 0.869), while average SR values> 24 during the first 12hours of TTM predicted poor outcome (CPC 3-5) with 91.5% sensitivity and 81.8% specificity (AUC, 0.906). Hourly BIS and SR values exhibited good predictive performance (AUC> 0.85), as soon as hour 2 for SR and hour 4 for BIS. ConclusionsBIS/SR are associated with patients’ potential for neurological recovery after CA. This finding could help to create awareness of the possibility of a better outcome in patients who might otherwise be wrongly considered as nonviable and to establish personalized treatment escalation plans.Full English text available from:www.revespcardiol.org/en

The role of Effortful Control in Pychopathology Amongst Older Psychiatric Patients

Background and aim: Based upon a person-centred approach, there is a growing interest in neurobiological transdiagnostic factors, such as reactive temperament (Behavioral Inhibition (BIS) and Behavioral Activation Systems (BAS)) and regulatory processes (Effortful Control (EC)). Three temperament-based personality types (Resilient, Undercontrolled and Overcontrolled type (RUO)) have been replicated in adolescents and younger adults with several clinical problems; with the resilient type (highest scores on EC) consistently showing less psychological symptoms. However, these RUO types have not been studied yet in older adults with mental disorders. Therefore, the current study investigates (1) whether these RUO types can be replicated based on the aforementioned reactive and regulative temperamental factors in older inpatients and (2) whether a higher EC is related to the presence of less psychopathology. Methods: The EC, BIS/BAS, SCL-90-R and ADP-IV questionnaires were administered to 96 older patients (&lt;= 60 years) admitted to a psychiatric hospital. Results: Cluster analysis resulted in a solution of three atypical types: a Resilient type (low BIS, mean BAS, high EC), a Dysregulated type (high BIS, high BAS, low EC) and an “Apathic” type (mean BIS, low BAS, mean EC). Comparison of means revealed that the Resilient type has the highest scores on EC and shows less clinical symptoms and maladaptive personality traits. Discussion: Of the 3 RUO types, only the Resilient type was fully replicated in older psychiatric patients. Strengthening EC might be useful as an additional therapy in order to reduce clinical symptoms, possibly leading to a better treatment outcome.DisclosureNo significant relationships.

Bispectral index and suppression ratio after cardiac arrest: are they useful as bedside tools for rational treatment escalation plans?

Introduction and objectivesMyocardial dysfunction contributes to early mortality (24-72 hours) among survivors of a cardiac arrest (CA). The benefits of mechanical support in refractory shock should be balanced against the patient's potential for neurological recovery. To date, these early treatment decisions have been taken based on limited information leading mainly to undertreatment. Therefore, there is a need for early, reliable, accessible, and simple tools that offer information on the possibilities of neurological improvement. MethodsWe collected data from bispectral index (BIS) and suppression ratio (SR) monitoring of adult comatose survivors of CA managed with targeted temperature management (TTM). Neurological status was assessed according to the Cerebral Performance Category (CPC) scale. ResultsWe included 340 patients. At the first full neurological evaluation, 211 patients (62.1%) achieved good outcome or CPC 1-2. Mean BIS values were significantly higher and median SR lower in patients with CPC 1-2. An average BIS> 26 during first 12 hours of TTM predicted good outcome with 89.5% sensitivity and 75.8% specificity (AUC of 0.869), while average SR values> 24 during the first 12 hours of TTM predicted poor outcome (CPC 3-5) with 91.5% sensitivity and 81.8% specificity (AUC, 0.906). Hourly BIS and SR values exhibited good predictive performance (AUC> 0.85), as soon as hour 2 for SR and hour 4 for BIS. ConclusionsBIS/SR are associated with patients’ potential for neurological recovery after CA. This finding could help to create awareness of the possibility of a better outcome in patients who might otherwise be wrongly considered as nonviable and to establish personalized treatment escalation plans.

Anesthetic Stability of Propofol, Dexmedetomidine, and Isoflurane by Measuring Bispectral Index (BIS) and Hemodynamic Indices: A Comparative Study

BackgroundHemodynamic changes and anesthetic awareness occurring during surgery under general anesthesia is a great concern for both surgeon and anesthesiologist. Maintenance of the adequate depth of anesthesia throughout the intraoperative period is important in maintaining hemodynamic stability, preventing intraoperative awareness, and avoiding postoperative recall.AimThis study aims to predict the anesthetic stability of propofol, dexmedetomidine, and isoflurane by measuring bispectral index (BIS) and hemodynamic indices.Materials and methodsThis is a prospective comparative study. Sixty patients of either sex, aged 18-60 years, with American Society of Anesthesiologist (ASA) physical status classification I and II, undergoing elective surgical procedures requiring general anesthesia were allocated into three groups of 20 each. Patients in each group were administered standard general anesthesia with routine hemodynamic monitoring along with BIS, and values were recorded at baseline and thereafter at every five-minute interval for the duration of surgery. Anesthesia was maintained in Group P using a bolus dose of propofol 1 milligram.kg-1 for 10 minutes followed by propofol infusion 50-75 microgram.kg-1.minute-1, Group D with a bolus dose of dexmedetomidine 1 microgram.kg-1 for 10 minutes followed by infusion 0.2-0.7 microgram.kg-1.hour-1, and Group I with isoflurane at 1 minimum alveolar concentration (MAC) for 10 minutes and then maintained between 0.5 MAC and 1.5 MAC until the duration of surgery. To maintain the surgical plane of anesthesia, the BIS score was monitored between 40 and 65. The quantitative variables were expressed as mean±SD and compared between groups using Student’s unpaired t-test. Data analysis was done using SPSS Statistics for Windows version 20.0 (IBM Corp., Armonk, NY, USA). A p-value of <0.05 was considered statistically significant.ResultsDuring intergroup comparison among study drugs, the mean BIS values were statistically significant among the groups (p<0.05). Hemodynamic indices were significantly better maintained in the dexmedetomidine group as compared to the isoflurane and propofol groups throughout the intraoperative period (p<0.05).ConclusionDexmedetomidine is better than propofol and isoflurane in maintaining the BIS score and hemodynamic parameters during the intraoperative period.

Time-dependent prognostic value of bispectral index and suppression ratio during targeted temperature management: an early triage tool for treatment escalation plans

Abstract Funding Acknowledgements Type of funding sources: None. Background Post-cardiac arrest myocardial dysfunction contributes to morbidity in survivors of cardiac arrest (CA) and, in case of refractory shock, some patients will benefit from aggressive mechanical support. In this scenario, a non-invasive, reliable and real-time estimation of potential neurological recovery is required to establish personalized treatment escalation plans. Methods We prospectively collected data of bispectral index (BIS) and suppression ratio (SR) monitoring of adult comatose survivors of CA consecutively admitted to an acute cardiac care unit and managed with targeted temperature management (TTM). Neurological status was assessed according to the Cerebral Performance Category (CPC) scale. Results We included 340 patients, 72.1% had an initial shockable rhythm, 72 (21.2%) were females and their mean age was 61.7 ± 14.3 years. Throughout 3-month follow-up, 210 patients (61.8%) achieved a CPC of 1-2 and 130 (38.2%) a CPC of 3-5. Mean BIS values were significantly higher and median SR lower in patients with CPC 1-2 (Figure 1). An average BIS value &amp;gt;26 during first 12 hours of TTM predicted good outcome with 89.3% sensitivity and 75.2% specificity (AUC of 0.86), while average SR values &amp;gt;24 during first 12 hours of TTM predicted poor outcome (CPC 3-5) with 83.6% of sensitivity and 91.8% of specificity (AUC of 0.92). Hourly BIS and SR values exhibited a good predictive performance (AUC &amp;gt; 0.85), starting as soon as hour 2 for SR and 4 for BIS. Conclusions BIS and SR real-time monitoring correlates with patient´s potential of neurological recovery after CA. This finding could help establish personalized treatment escalation plans that reduce consequences of inappropriate interventions, economic costs and uncertainty burden of the patient´s family.

The Effects of Ketamin-Midazolam and Ketamin-Propofol on Bispectral Index Score as Sedatives During Bone Marrow Puncture Procedure Among Pediatrics

Background: Bone Marrow Puncture (BMP) is an invasive procedure associated with pain and anxiety. The ketamine-midazolam and the ketamine-propofol is an effectivecombination with minimal side effects. This study of the study aims to compare the effect of the combination of ketamine-midazolam and ketamine- propofol on sedation depth based on BIS in pediatric leukemia patients undergoing BMP.&#x0D; Methods: This study was a randomized controlled trial that was done single-blinded. The population was all pediatric patients diagnosed with leukemia who underwent BMP at RSMH and performed sedation. The research sample is the population that fulfill the inclusion and exclusion criteria. The sample size for each group was 25, with 50 Subjects in total. Sampling was done by block randomization.&#x0D; Results: This study found no differences in sex, age, and body weight between the two groups ([p=1.000], [p=0.845], and [p=0.147], respectively). In this study, there was no difference in mean MAP (p=0.592), oxygen saturation (p=0.164), heart rate (p=0.098), and respiratory rate (p=0.252) before intervention between the two groups. BIS value of the two groups had significant difference before and after the intervention where the two groups could reduce BIS to reach the optimal value of sedation &lt;60 (p &lt;0.05) There was no difference in BIS before intervention in the two groups (p=0.385). In this study, it was found that hypersalivation occurred more frequently in the ketamine-midazolam combination group.&#x0D; Conclusion: The combination of ketamine-midazolam and ketamine-propofol was equally good for sedation as indicated by a decrease in the mean BIS in patients undergoing BMP.

Intra‐individual variability in processed EEG (bispectral index monitor) under general anesthesia predicts postoperative cognitive change after total knee arthroplasty

AbstractBackgroundPrevious research shows 1) clock drawing performance slows for older adults after total knee arthroplasty (TKA; Hizel et al., 2018), and 2) brain‐behavioral associations with intra‐individual variability on an EEG‐derived index during TKA (Hernaiz et al., 2019). The current study expanded upon these findings by examining how preoperative cognition and intraoperative responses to anesthesia may predict postoperative clock drawing performance. We hypothesized greater intraoperative intra‐individual BIS variability would explain a significant portion of variance in four primary latency measures to command and copy condition at 3‐weeks following surgery.MethodThe final prospectively recruited IRB consented participant sample included 54 non‐demented patients age 60+ receiving TKA under general anesthesia. Consistent with Hernaiz et al., (2019), derived 2‐channel EEG variability was studied from tourniquet inflation to tourniquet release, thereby establishing a consistent period of examination. Intra‐individual variability was calculated as the squared deviation from the mean BIS value over the duration of measurement. Clock drawing to command and copy was recorded with digital pen technology and scored with semiautomatic rater‐guided software (Souillard‐Mandar et al., 2016). Outcome latency variables of interest: 1) total completion time in seconds (TCT), 2) time prior to setting the first hand in seconds (pre‐first hand latency; PFHL), 3) seconds after drawing the clock face to next pen stroke (post‐clock face latency; PCFL).ResultAt 3‐weeks, participants took, on average, six seconds longer to complete the drawing compared to baseline performance, and two seconds longer to set the first clock hand. Correcting for baseline performance, separate hierarchical regressions showed intra‐individual EEG‐derived variability explained an additional 4.3% of variance in postoperative command TCT (F(2,51)=28.301, p&lt;.038, R2=.536, ∆R2=.043), such that those with greater intraoperative BIS variability took longer to complete the drawing to command.ConclusionIn non‐demented older adults undergoing TKA, higher intra‐individual BIS variability significantly contributed to total clock drawing time during the command condition. Command total completion time is sensitive to numerous cognitive domains including processing speed, language, working memory, and declarative memory (Dion et al., 2020). Fluctuations during general anesthesia as recorded on an EEG‐derived index may help explain postoperative slowing during clock drawing at 3‐weeks post‐surgery.

Cerebral oxygenation assessed by near-infrared spectroscopy in the sitting and prone positions during posterior fossa surgery: a prospective, randomized clinical study

ObjectivesSitting position (SP) or prone position (PP) are used for posterior fossa surgery. The SP induced reduction in cerebral blood flow and cerebral oxygen saturation (rSO2) has been shown in shoulder surgeries, but there is not enough data in intracranial tumor surgery. Studies showed that PP is safe in terms of cerebral oxygen saturation in patients undergoing spinal surgery. Our hypothesis is that the SP may improve cerebral oxygenation in the patients with intracranial pathologies due to reduction in intracranial pressure. Therefore, we compared the effects of the SP and PP on rSO2 in patients undergoing posterior fossa tumor surgery. MethodsData were collected patients undergoing posterior fossa surgery, 20 patients in SP compared to 21 patients in PP. The rSO2 was assessed using INVOS monitor. Heart rate (HR), mean arterial pressure (MAP), EtCO2, BIS, and bilateral rSO2 were recorded preoperatively, and at 5, 8, and 11.ßminutes after the intubation and every 3.ßminutes after patient positioning until the initial surgical incision. ResultsCerebral oxygenation slowly reduced in both the sitting and prone position patients following the positioning (p.ß<.ß0.002), without any difference between the groups. The HR and MAP were lower in the sitting SP after positioning compared to the PP. ConclusionNeurosurgery in the SP and PP is associated with slight reduction in cerebral oxygenation. We speculate that if we rise the lower limit of MAP, we might have showed the beneficial effect of the SP on rSO2.

A Review of Current Literature of Interest to the Office-Based Anesthesiologist.

A Review of Current Literature of Interest to the Office-Based Anesthesiologist.

The association of bispectral index values and metrics of cerebral perfusion during cardiopulmonary bypass

Study objectiveLow bispectral index (BIS) values have been associated with adverse postoperative outcomes. However, trials of optimizing BIS by titrating anesthetic administration have reported conflicting results. One potential explanation is that cerebral perfusion may also affect BIS, but the extent of this relationship is not clear. Therefore, we examined whether BIS would be associated with cerebral perfusion during cardiopulmonary bypass, when anesthetic concentration was constant. DesignObservational cohort study. SettingCardiac operating room. PatientsSeventy-nine patients with cardiopulmonary bypass surgery were included. MeasurementsContinuous BIS, mean arterial blood pressure (MAP), cerebral blood flow velocity (CBFV), and regional cerebral oxygen saturation (rSO2) were monitored, with analysis during a period of constant anesthetic. Mean flow index (Mx) was calculated as Pearson correlation between MAP and CBFV. The lower limit of autoregulation (LLA) was identified as the MAP value at which Mx increased >0.4 with decreasing blood pressure. Postoperative delirium was assessed using the 3D-Confusion Assessment Method. ResultsMean BIS was lower during periods of MAP < LLA compared with BIS when MAP>LLA (mean 49.35 ± 10.40 vs. 50.72 ± 10.04, p = 0.002, mean difference = 1.38 [standard error: 0.42]). There was a dose response effect, with the BIS proportionately decreasing as MAP decreased below LLA (β = 0.15, 95% CI for the average slope across all patients 0.07 to 0.23, p < 0.001). In contrast, BIS was relatively unchanged when MAP was above LLA (β = 0.03, 95% CI for the average slope across all patients −0.02 to 0.09, p = 0.22). Additionally, increasing CBFV and rSO2 were associated with increasing BIS. Patients with postoperative delirium had lower mean BIS and higher percentage of time duration with BIS <45 compared to patients without delirium. ConclusionsThere was an association of BIS and metrics of cerebral perfusion during a period of constant anesthetic administration, but the absolute magnitude of change in BIS as MAP decreased below the LLA was small.

Factors associated with somnolence during brain function mapping in awake craniotomy

Somnolence during brain function mapping is one of the factors that inhibit the accomplishment of the goals of awake craniotomy. We examined the effect of anesthesia depth measured by bispectral index (BIS) during pre-awake phase on somnolence during brain function mapping and also explored the factors associated with somnolence. We examined the association between BIS values during pre-awake phase and somnolence during the first 30 min of brain function mapping in 55 patients who underwent awake craniotomy at Kyoto University Hospital from 2015 to 2018. The pre-awake BIS value was defined as the mean BIS value for 60 min before the removal of the airway. Somnolence during brain function mapping was the primary outcome, defined as either of the following conditions: inability to follow up, disorientation, or inability to assess speech function. Additionally, we compared patient or perioperative variables between patients with/without somnolence. Somnolence occurred in 14 patients (25.5%), of which 6 patients (10.9%) were unable to complete brain function mapping. There was no significant difference in the pre-awake BIS value between patients with/without somnolence (median: 46 vs. 49, P = 0.192). Somnolence was not significantly associated with age, gender, and the number of preoperative anticonvulsive drugs, but patients with somnolence had a significantly lower preoperative Western Aphasia Battery (WAB) aphasia quotient score (median 93.8 vs. 98.6, P = 0.011). We did not find an association between pre-awake BIS value and somnolence during brain function mapping. Somnolence likely occurs in patients with a low preoperative WAB aphasia quotient score.