Density spectral array during the intra and postoperative of a left frontal craniotomy / Matriz de Densidad Espectral durante el intra y el posoperatorio de una craneotomía frontal izquierda

Abstract We present the case of an adult with an extensive left frontal meningioma. He was scheduled for resection by craniotomy. During the surgery we used the density spectral array (DSA) and asymmetry obtained from Bispectral Index VISTA Monitoring System Bilateral. We observed a power increase in low frequency (0.1-1 Hz) and alpha bands (8-12 Hz) in the left hemisphere, where the meningioma was located. In this case, DSA was useful during and after the surgery because it provided information about the hemisphere with maximum brain activity and its subsequent normalization, which may reflect the effectiveness of the surgery.

Resumen Presentamos el caso de un paciente adulto con diagnóstico de un meningioma extenso a nivel frontal izquierdo, que fue programado para exéresis mediante craneotomía. Durante la cirugía se utilizó la Matriz de Densidad Espectral (MDE) y la asimetría obtenida del Sistema de Monitorización VISTATM del Índice Biespectral Bilateral (BVMS). Se observó un aumento de potencia en las bandas de baja frecuencia (0.1-1Hz) y en las bandas alfa (812 Hz) del hemisferio cerebral izquierdo, donde se encontraba el meningioma. En este caso la MDE demostró su utilidad durante y después de la cirugía, al proporcionar información sobre el hemisferio con registro de máxima actividad cerebral y su posterior normalización, reflejando así la efectividad de la cirugía.

Evaluation of Bispectral Index time delay in response to anesthesia induction: an observational study / Avaliação do tempo de atraso do índice bispectral na resposta à indução da anestesia: estudo observacional

Abstract Background and objectives According to the manufacturer, the Bispectral Index (BIS) has a processing time delay of 5-10 s. Studies addressing this have suggested longer delays. We evaluated the time delay in the Bispectral Index response. Methods Based on clinical data from 45 patients, using the difference between the predicted and the real BIS, calculated during a fixed 3 minutes period after the moment the Bispectral Index dropped below 80 during the induction of general anesthesia with propofol and remifentanil. Results The difference between the predicted and the real BIS was in average 30.09 ± 18.73 s. Conclusion Our results may be another indication that the delay in BIS processing may be much longer than stated by the manufacture, a fact with clinical implications.

Resumo Justificativa e objetivos De acordo com o fabricante, o índice bispectral (BIS) tem um tempo de processamento de cinco a dez segundos. Estudos que avaliaram esse tempo de processamento sugeriram atrasos mais longos. Nós avaliamos o tempo de atraso na resposta do BIS. Métodos Com base em dados clínicos de 45 pacientes, calculamos a diferença entre o tempo de atraso previsto e real do índice bispectral durante um período fixo de três minutos após o momento em que o BIS caiu abaixo de 80 durante a indução da anestesia geral com propofol e remifentanil. Resultados A diferença entre o BIS previsto e real foi em média 30,09 ± 18,73 segundos. Conclusão Nossos resultados sugerem que o atraso no processamento do índice bispectral pode ser muito maior do que o declarado pelo fabricante, um fato com implicações clínicas.

Evaluation of a closed-loop intravenous total anesthesia delivery system with BIS monitoring compared to an open-loop target-controlled infusion (TCI) system: randomized controlled clinical trial / Evaluación de un sistema de administración de Anestesia Total Intravenosa en lazo cerrado con neuromonitoría, comparado con un sistema de lazo abierto de infusión controlada por objetivo (TCI): Ensayo clínico controlado

Abstract Introduction: Intravenous general anesthesia is an anesthetic technique that can be administered with TCI (target-controlled infusion) or closed-loop systems. The authors designed an automatic delivery system using clinical variables such as bispectral index (BIS), heart rate, and blood pressure. Objective: To evaluate the clinical and technical performance of this controller by comparing it to a TCI system. Methods: This was a single-blind, randomized, controlled clinical trial in which 150 patients were recruited: 75 for the TCI group and 75 for the closed loop with BIS. Clinical performance was determined according to the mean percentage of time spent in the BIS range of 40 to 60 during anesthetic maintenance. In addition, adequate intraoperative analgesia, technical performance, intraoperative awakening, and intraoperative recall were evaluated. Results: The primary outcome showed a mean BIS time between 40 and 60 for the closed loop of 75.24% (± 15.78) versus 59.5% (± 20.3) for the TCI system, with an absolute difference of 15.8%, 95% confidence interval (CI): 9.9 to 21.65, P < 0.0001. The mean time in intraoperative analgesia was 82.4% (25.1) in closed loop and 70.77% (± 32.8) in TCI, with a difference of 4.76 (95% CI: 2.23-21.06), P = 0.016. There was no difference in intraoperative recall. Conclusion: The closed-loop system was better at maintaining a BIS in the range of 40 to 60 during a general anesthetic than the open system or TCI.

Resumen Introducción: La anestesia total endovenosa es una técnica anestésica que puede administrarse con sistemas de TCI (Target Controlled Infusión) o de lazo cerrado. Los autores diseñaron un sistema de administración automática empleando variables clínicas como índice biespectral (BIS), frecuencia cardiaca y presión arterial. Objetivo: Evaluar el desempeño clínico y técnico de este controlador, comparándolo con un sistema de TCI. Métodos: Este fue un ensayo clínico controlado, aleatorizado y de ciego único, en el cual se reclutaron 150 pacientes: 75 en el grupo de TCI y 75 en lazo cerrado con BIS. El desempeño clínico fue determinado de acuerdo al porcentaje promedio de tiempo de permanencia en el rango de BIS entre 40-60 durante el mantenimiento anestésico. Adicionalmente se evaluó analgesia intraoperatoria adecuada, desempeño técnico, despertar intraoperatorio y recuerdo intraoperatorio. Resultados: Para el desenlace primario se encontró un tiempo promedio de BIS entre 40-60 para el lazo cerrado de un 75.24% (+/-15.78) vs. 59.5% (+/- 20.3) para el sistema TCI, con una diferencia del 15.8%, IC del 95%: 9.9 a 21.65, p < 0.0001. El promedio de tiempo en analgesia intraoperatoria adecuada fue del 82.4% (25.1) en lazo cerrado y 70.77% (+/- 32.8) en TCI, con una diferencia de 4.76 (IC del 95%: 2.23 a 21.06), p=0.016. No hubo diferencias en recuerdo intraoperatorio. Conclusión: El sistema de lazo cerrado fue mejor para mantener un BIS en rango de 40-60 durante un acto anestésico que el sistema abierto o TCI.

Validity of bispectral index monitoring during deep sedation in children with spastic cerebral palsy undergoing injection of botulinum toxin / 대한마취과학회지

BACKGROUND: This prospective study aimed to determine whether the bispectral index (BIS) is a valid objective tool for differentiating adequate from inadequate deep sedation in spontaneously breathing children with cerebral palsy (CP).METHODS: Propofol was titrated to increase the level of sedation with a continuous infusion of remifentanil at a rate of 0.05 μg/kg/min while maintaining spontaneous ventilation in 22 children with spastic CP, aged 3–18 years. The depth of sedation was assessed using the University of Michigan Sedation Scale (UMSS) and the Modified Observer’s Assessment of Alertness and Sedation (MOAAS) scale. Receiver operating characteristic curve analysis was performed to determine the cutoff BIS values for deep sedation, defined as a UMSS score of 3–4 and a MOAAS score of 0–1.RESULTS: The BIS values significantly changed with the increase in the level of sedation across both the UMSS and MOAAS scores (P < 0.001). The BIS values correlated with the UMSS (r = −0.795, P < 0.001) and MOAAS (r = 0.815, P < 0.001) scores. The cutoff BIS value to detect adequate deep sedation in children with CP was 61.5 (UMSS score: sensitivity 0.860, specificity 0.814; MOAAS score: sensitivity 0.794, specificity 0.811).CONCLUSIONS: The BIS value strongly correlates with the clinical sedation scales, such as the UMSS and MOAAS, during deep sedation in children with CP. Therefore, BIS monitoring can be used as a valid tool for assessing the level of propofol sedation in spontaneously breathing children with CP undergoing a botulinum toxin injection.

Awareness during general anesthesia despite simultaneous bispectral index and end-tidal anesthetic gas concentration monitoring / 영남의대학술지

Awareness during general anesthesia occurs in approximately 0.1–0.2% of cases; nevertheless, particular attention is required because it can lead to critical complications including insomnia, depression, anxiety, and post-traumatic stress disorder. To prevent these complications, bispectral index (BIS) and end-tidal anesthetic gas (ETAG) concentration monitoring are commonly used to examine patient consciousness during surgery. In the present case, an 80-year-old man was scheduled for total gastrectomy. Anesthesia was maintained using desflurane 4.0–5.0% vol, oxygen, and nitrous oxide. The authors simultaneously monitored BIS, which was maintained between 37 and 43, and ETAG, which was maintained between 0.9 and 1.2 minimum alveolar concentration (MAC). After the operation, however, the authors were surprised to learn that the patient complained of awareness during anesthesia. Although BIS and ETAG concentration monitoring are useful in preventing awareness during anesthesia, they cannot be completely trusted. Even though BIS was maintained at approximately 40 and ETAG at 0.7–1.3 MAC, awareness during anesthesia occurred.

Comparative Analysis of Phase Lag Entropy and Bispectral Index as Anesthetic Depth Indicators in Patients Undergoing Thyroid Surgery with Nerve Integrity Monitoring

BACKGROUND: Most depth of anesthesia (DOA) monitors rely on the temporal characteristics of a single-channel electroencephalogram (EEG) and cannot provide spatial or connectivity information. Phase lag entropy (PLE) reflects DOA by calculating diverse connectivity from temporal patterns of phase relationships. The aim of this study was to compare the performance of PLE and bispectral index (BIS) monitors for assessing DOA during anesthesia induction, nerve integrity monitoring (NIM), and anesthesia emergence. METHODS: Thirty-five patients undergoing elective thyroid surgery with recurrent laryngeal nerve NIM received propofol and remifentanil via target-controlled infusion. After applying PLE and BIS monitors, propofol infusion was initiated at a calculated effect site concentration (Ce) of 2 µg/mL and then increased in 1-µg/mL Ce increments. After propofol Ce reached 5 μg/mL, a remifentanil infusion was begun, and anesthesia induction was considered complete. During NIM, PLE and BIS values were compared at a specific time points from platysma muscle exposure to subcutaneous tissue closure. PLE and BIS values were recorded continuously from preanesthetic state to full recovery of orientation; bias and limits of agreement between monitors were calculated. RESULTS: PLE and BIS values decreased progressively with increasing propofol Ce during anesthetic induction and increased by stages during emergence. The prediction probabilities of PLE and BIS for detecting propofol Ce changes were 0.750 and 0.756, respectively, during induction and 0.749 and 0.746, respectively, during emergence. No aberrant PLE or BIS values occurred during NIM. Correlation coefficients for BIS and PLE were 0.98 and 0.92 during induction and emergence, respectively. PLE values were significantly higher than BIS values at full recovery of orientation. Estimated bias between monitors was −4.16 ± 8.7, and 95% limits of agreement were −21.21 to 12.89. CONCLUSION: PLE is a reasonable alternative to BIS for evaluating consciousness and DOA during general anesthesia and during NIM. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0003490

Assessment of phase-lag entropy, a new measure of electroencephalographic signals, for propofol-induced sedation / 대한마취과학회지

BACKGROUND: Phase-lag entropy (PLE) was recently described as a measurement of temporal pattern diversity in the phase relationship between two electroencephalographic signals from prefrontal and frontal montages. This study was performed to evaluate the performance of PLE for assessing the depth of sedation. METHODS: Thirty adult patients undergoing upper limb surgery with a brachial plexus block were administered propofol by target-controlled infusion. The depth of sedation was assessed using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. The effect-site concentration (Ce) of propofol was initially started at 0.5 μg/ml and was increased in increments of 0.2 μg/ml until an OAA/S score of 1 was reached. Three minutes after the target Ce was reached, the PLE, bispectral index (BIS), and level of sedation were assessed. Correlations between the OAA/S score and PLE or BIS were determined. The prediction probabilities (P(k)) of PLE and BIS were also analyzed. RESULTS: The PLE values were closely correlated with the OAA/S scores (Spearman's Rho = 0.755; P < 0.001) to an extent comparable with the correlation between the BIS and OAA/S score (Spearman's Rho = 0.788; P < 0.001). The P(k) values of PLE and BIS were 0.731 and 0.718, respectively. CONCLUSIONS: PLE is a new and reliable consciousness monitoring system for assessing the depth of sedation induced by propofol, which is comparable with the BIS.

Influence of propofol dose and blood components on duration of electrical seizures in electroconvulsive therapy / Influência da dose de propofol e dos componentes sanguíneos na duração das convulsões elétricas em eletroconvulsoterapia

Abstract Background and objectives: Propofol is commonly employed as a hypnotic agent to perform electroconvulsive therapy, but it exhibits also anticonvulsant properties. The main objective was to study the effect of the weight-adjusted dose of propofol on duration of the electrical seizure. Secondary objectives were to study the effect of absolute dose of propofol on duration of electrical seizure, the effect of both absolute and weight-adjusted doses on values of bispectral index, and the influence of blood chemistry on anticonvulsant effect. Methods: After approval of the Institutional Review Board, a retrospective chart review was performed of all patients who underwent at least one electroconvulsive therapy session. Multiple lineal regression analysis adjusted for potential confounders was employed to explore the effect of propofol dosage on values of bispectral index and on duration of seizure; bivariate correlation analyses were previously performed to identify variables fulfilling confounding criteria, specifically values of Spearman's rho >0.10. Results of regression analysis were expressed as B coefficient with its 95% confident interval. Results: 76 patients received 631 acute phase sessions. Propofol showed a statistically significant negative effect on duration of seizure (specifically a reduction of 4.081 s for every mg.kg−1 of propofol; CI95%: −7906 to −0.255, p = 0.037) but not on bispectral index values. Slight anemia and hypoalbuminemia were very infrequent conditions, and the anticonvulsant effect was not influenced by these parameters. Conclusions: Propofol weight-adjusted dose is negatively related to duration of seizures. It should be carefully titrated when employed to perform electroconvulsive therapy.

Resumo Justificativa e objetivos: O propofol é comumente usado como agente hipnótico na terapia eletroconvulsiva, mas apresenta também propriedades anticonvulsivantes. O objetivo principal foi avaliar o efeito da dose de propofol ajustada ao peso na duração da convulsão elétrica. Os objetivos secundários foram avaliar o efeito da dose total de propofol na duração da convulsão elétrica, o efeito da dose tanto total quanto ajustada ao peso nos valores do índice bispectral e a influência da bioquímica do sangue no efeito anticonvulsivante. Métodos: Após aprovação do Comitê de Ética em Pesquisa, foi feita uma revisão retrospectiva dos prontuários de todos os pacientes que fizeram pelo menos uma sessão de eletroconvulsoterapia. Análise de regressão linear múltipla ajustada para potenciais confundidores foi feita para explorar o efeito da dosagem de propofol sobre os valores do índice bispectral e a duração da convulsão; análises de correlação bivariada foram previamente feitas para identificar as variáveis que atendem aos critérios de confusão, especificamente valores de r de Spearman > 0,10. Os resultados da análise de regressão foram expressos como coeficiente B com intervalo de confiança de 95%. Resultados: Setenta e seis pacientes receberam 631 sessões de fase aguda. Propofol mostrou um efeito negativo estatisticamente significativo sobre a duração da convulsão (especificamente uma redução de 4,081 segundos para cada mg.kg−1 de propofol; IC de 95%: -7906 para -0,255, p = 0,037), mas não para os valores do índice bispectral. Anemia leve e hipoalbuminemia foram condições muito raras e o efeito anticonvulsivante não foi influenciado por esses parâmetros. Conclusões: A dose de propofol ajustada ao peso está negativamente relacionada com a duração das crises convulsivas, deve ser cuidadosamente titulada quando usada na terapia eletroconvulsiva.

Application of a pharmacokinetics-pharmacodynamics approach to the free propofol plasma levels during coronary artery bypass grafting surgery with hypothermic cardiopulmonary bypass

OBJECTIVES: The objective of this study was to apply a pharmacokinetics-pharmacodynamics approach to investigate the free propofol plasma levels in patients undergoing coronary artery bypass grafting under hypothermic conditions compared with the off-pump procedure. METHODS: Nineteen patients scheduled for on-pump coronary artery bypass grafting under hypothermic conditions (n=10) or the equivalent off-pump surgery (n=9) were anesthetized with sufentanil and propofol target-controlled infusion (2 μg/mL) during surgery. The propofol concentration was then reduced to 1 μg/mL, and a pharmacokinetics-pharmacodynamics analysis using the maximum-effect-sigmoid model obtained by plotting the bispectral index values against the free propofol plasma levels was performed. RESULTS: Significant increases (two- to five-fold) in the free propofol plasma levels were observed in the patients subjected to coronary artery bypass grafting under hypothermic conditions. The pharmacokinetics of propofol varied according to the free drug levels in the hypothermic on-pump group versus the off-pump group. After hypothermic coronary artery bypass was initiated, the distribution volume increased, and the distribution half-life was prolonged. Propofol target-controlled infusion was discontinued when orotracheal extubation was indicated, and the time to patient extubation was significantly higher in the hypothermic on-pump group than in the off-pump group (459 versus 273 min, p=0.0048). CONCLUSIONS: The orotracheal intubation time was significantly longer in the hypothermic on-pump group than in the off-pump group. Additionally, residual hypnosis was identified through the pharmacokinetics-pharmacodynamics approach based on decreases in drug plasma protein binding in the hypothermic on-pump group, which could explain the increased hypnosis observed with this drug in this group of patients.

Sudden Bispectral Index Reduction and Suppression Ratio Increase Associated with Bradycardia in a Patient Undergoing Breast Conserving Surgery

BACKGROUND: The bispectral index (BIS) is a valuable indicator for measuring sedation levels and patient consciousness. Recent reports have highlighted its clinical value as an indicator for anesthesia-related cerebral hypoperfusion and ischemic brain damage. CASE REPORT: A 55-year-old female patient underwent right breast conservation surgery during general anesthesia. During surgery, the patient experienced abrupt bradycardia (heart rate of 36 bpm) without hypotension. During bradycardia, her BIS was severely reduced from 45 to 20 along with elvated suppression ratio (50). After injection of 0.5mg of atropine, her BIS level was recovered, her heart rate was increased, and her suppression ratio was decreased. CONCLUSION: The patient recovered from anesthesia without showing any signs of neurological sequelae based on BIS level monitoring.

Anesthesia recovery comparison between remifentanil-propofol and remifentanil-desflurane guided by Bispectral Index® monitoring / Comparação da recuperação pós-anestésica entre remifentanil-propofol e remifentanil-desflurano guiada pela monitoração do Índice Bispectral®

Abstract Background and objectives There is a strong demand for fast and predictable anesthesia recovery with few side effects. Choice of the hypnotic agent could impact on that. This study investigated the differences between recoveries after remifentanil-propofol and remifentanil-desflurane anesthesias guided by bispectral index (BIS®). Methods Forty patients were randomly assigned into 2 groups according to the anesthesia technique applied: remifentanil-propofol (REM-PRO) and remifentanil-desflurane (REM-DES). After the discontinuation of the anesthetics, the times to extubation, to obey commands and to recover the airway protection reflex were recorted. In the post-anesthetic recovery room (PACU) it was recorded the occurrence of nausea and vomiting (PONV), scores of Ramsay sedation scale and of numeric pain scale (NPS), morphine dose and length of stay in the unit. Results Data from 38 patients were analyzed: 18 from REM-PRO and 20 from REM-DES group. Anesthesia times were similar (REM-PRO = 193 min, SD 79.9 vs. 175.7 min, SD 87.9 REM-DES; p = 0.5). REM-DES had shorter times than REM-PRO group: time to follow command (8.5 min; SD 3.0 vs. 5.6 min; SD 2.5; p = 0.0) and extubation time (6.2 min; 3.1-8.5 vs. 9.5 min; 4.9-14.4; p = 0.0). Times to recover airway protective reflex were similar: 16 patients from REM-PRO (88.9%) restored the airway protective reflex 2 min after extubation vs. 17 from REM-DES (89.5%); and 2 patients from REM-PRO (11.1%) vs. 2 from REM-DES (10.5%) 6 min after extubation, p = 1. Ramsay sedation score, NPS, PONV incidents, morphine dose and PACU stay of length PACU were also similar. Conclusion Remifentanil-desflurane-based anesthesia has a faster extubation time and to follow command than remifentanil-propofol-based anesthesia when both guided by BIS®.

Resumo Justificativa e objetivos Há uma forte demanda por recuperação pós-anestésica rápida e previsível com poucos efeitos adversos. A escolha do agente hipnótico pode influenciar isso. Este estudo investigou as diferenças da recuperação no pós-operatório entre as técnicas anestésicas com remifentanil-propofol e com remifentanil-desflurano ambas com monitoração guiada pelo índice bispectral (BIS ®). Métodos Foram randomicamente distribuídos 40 pacientes em dois grupos de acordo com a técnica anestésica aplicada: remifentanil-propofol (REM-PRO) e remifentanil-desflurano (REM-DES). Após a descontinuação dos anestésicos foram registrados os tempos para extubação, obedecer a comandos e recuperar o reflexo de proteção das vias aéreas. Na sala de recuperação pós-anestésica (SRPA) foi registrado a ocorrência de náuseas e vômitos (NVPO), os escores na escala de sedação de Ramsay e na escala numérica de dor (END), a dose de morfina utilizada e o tempo de permanência nesta unidade. Resultados Os dados de 38 pacientes foram analisados: 18 do grupo REM-PRO e 20 do grupo REM-DES. Os tempos de anestesia foram semelhantes (REM-PRO = 193 minutos, DP 79,9 vs. 175,7 minutos, DP 87,9 REM-DES; p = 0,5). O grupo REM-DES apresentou tempos mais curtos do que o grupo REM-PRO: tempo para obedecer a comandos (8,5 minutos; DP 3,0 vs. 5,6 minutos; DP 2,5; p = 0,0) e tempo de extubação (6,2 minutos; 3,1-8,5 vs. 9,5 minutos; 4,9-14,4; p = 0,0). Os tempos para recuperação do reflexo de proteção das vias aéreas foram semelhantes: 16 pacientes do grupo REM-PRO (88,9%) recuperaram o reflexo de proteção das vias aéreas dois minutos após a extubação vs. 17 do grupo REM-DES (89,5%) e dois pacientes do grupo REM-PRO (11,1%) vs. dois do REM-DES (10,5%) seis minutos após a extubação, p = 1. Os escores de Ramsay, NPS, a incidência de NVPO, a dose de morfina e o tempo de permanência na SRPA também foram semelhantes. Conclusão A anestesia com remifentanil-desflurano tem um perfil de recuperação da anestesia pós-anestésica mais rápido do que o da anestesia com remifentanil-propofol quando ambas guiadas pelo BIS®.

Anesthetic requirements measured by bilateral bispectral analysis and femoral blockade in total knee arthroplasty / Necessidade de anestésicos avaliada com a análise do índice bispectral bilateral e bloqueio femoral em artroplastia total de joelho

Abstract Background and objectives A continuous peripheral nerve blockade has proved benefits on reducing postoperative morphine consumption; the combination of a femoral blockade and general anesthesia on reducing intraoperative anesthetic requirements has not been studied. The objective of this study was to determine the relevance of timing in the performance of femoral block to intraoperative anesthetic requirements during general anesthesia for total knee arthroplasty. Methods A single-center, prospective cohort study on patients scheduled for total knee arthroplasty, were sequentially allocated to receive 20 mL of 2% mepivacaine throughout a femoral catheter, prior to anesthesia induction (Preoperative) or when skin closure started (Postoperative). An algorithm based on bispectral values guided intraoperative anesthetic management. Postoperative analgesia was done with an elastomeric pump of levobupivacaine 0.125% connected to the femoral catheter and complemented with morphine patient control analgesia for 48 hours. The Kruskall Wallis and the chi-square tests were used to compare variables. Statistical significance was set at p < 0.05. Results There were 94 patients, 47 preoperative and 47 postoperative. Lower fentanyl and sevoflurane were needed intraoperatively in the Preoperative group; median values and range: 250 (100-600) vs 450 (200-600) µg and 21 (12-48) vs 32 (18-67) mL p = 0.001, respectively. There were no differences in the median verbal numeric rating scale values 4 (0-10) vs 3 (0-10); and in median morphine consumption 9 (2-73) vs 8 (0-63) mg postoperatively. Conclusions A preoperative femoral blockade is useful in decreasing anesthetic requirements in total knee arthroplasty surgery but no added effect in the postoperative analgesic control.

Resumo Justificativa e objetivos O bloqueio contínuo de nervos periféricos provou ser benéfico para reduzir o consumo de morfina no pós-operatório. A combinação de um bloqueio femoral e anestesia geral para reduzir a necessidade de anestésicos no intraoperatório ainda não foi avaliada. O objetivo deste estudo foi determinar a relevância do momento propício durante o bloqueio femoral para a necessidade de anestésicos no intraoperatório durante a anestesia geral para artroplastia total de joelho (ATJ). Métodos Estudo prospectivo de coorte de pacientes agendados para ATJ. Os pacientes foram sequencialmente alocados em grupos para receber mepivacaína a 2% (20 mL) durante a inserção do cateter femoral, antes da indução da anestesia (pré-operatório) ou no início do fechamento da pele (pós-operatório). Um algoritmo com base nos valores do BIS orientou o manejo da anestesia no intraoperatório. Analgesia no pós-operatório foi administrada via bomba elastomérica de levobupivacaína a 0,125% conectada ao cateter femoral e complementada com analgesia (morfina) controlada pelo paciente durante 48 horas. Os testes de Kruskall-Wallis e do qui-quadrado foram usados para comparar as variáveis. A significância estatística foi estabelecida em p < 0,05. Resultados Foram estudados 94 pacientes, 47 no pré-operatório e 47 no pós-operatório. Houve menos necessidade de fentanil e sevoflurano durante o período intraoperatório no grupo pré-operatório; medianas e variações dos valores: 250 (100-600) vs. 450 (200-600) µg e 21 (12-48) vs. 32 (18-67) mL p = 0,001, respectivamente. Não houve diferenças nas medianas dos valores das escalas de classificação numérica e verbal, 4 (0-10) vs. 3 (0-10), e nas medianas do consumo de morfina, 9 (2-73) vs. 8 (0-63) mg no pós-operatório. Conclusões O bloqueio femoral no pré-operatório é útil para diminuir a necessidade de anestésicos em ATJ, mas não tem efeito adicional no controle da analgesia no pós-operatório.

Postoperative surveillance in neurosurgical patients - usefulness of neurological assessment scores and bispectral index / Monitoramento de pacientes neurocirúrgicos no pós-operatório - utilidade dos escores de avaliação neurológica e do índice bispectral

Abstract Background and objectives: We examined the additive effect of the Ramsay scale, Canadian Neurological Scale (CNS), Nursing Delirium Screening Scale (Nu-DESC), and Bispectral Index (BIS) to see whether along with the assessment of pupils and Glasgow Coma Scale (GCS) it improved early detection of postoperative neurological complications. Methods: We designed a prospective observational study of two elective neurosurgery groups of patients: craniotomies (CG) and non-craniotomies (NCG). We analyze the concordance and the odds ratio (OR) of altered neurological scales and BIS in the Post-Anesthesia Care Unit (PACU) for postoperative neurological complications. We compared the isolated assessment of pupils and GCS (pupils-GCS) with all the neurologic assessment scales and BIS (scales-BIS). Results: In the CG (n = 70), 16 patients (22.9%) had neurological complications in PACU. The scales-BIS registered more alterations than the pupils-GCS (31.4% vs. 20%; p < 0.001), were more sensitive (94% vs. 50%) and allowed a more precise estimate for neurological complications in PACU (p = 0.002; OR = 7.15, 95% CI = 2.1-24.7 vs. p = 0.002; OR = 9.5, 95% CI = 2.3-39.4). In the NCG (n = 46), there were no neurological complications in PACU. The scales-BIS showed alterations in 18 cases (39.1%) versus 1 (2.2%) with the pupils-GCS (p < 0.001). Altered CNS on PACU admission increased the risk of neurological complications in the ward (p = 0.048; OR = 7.28, 95% CI = 1.021-52.006). Conclusions: Applied together, the assessment of pupils, GCS, Ramsay scale, CNS, Nu-DESC and BIS improved early detection of postoperative neurological complications in PACU after elective craniotomies.

Resumo Justificativa e objetivos: Avaliamos o efeito aditivo da escala de Ramsay, Escala Neurológica Canadense (CNS), Escala da Enfermagem de Triagem de Delírio (Nu-DESC) e Índice Bispectral (BIS) para observar se, juntamente com a avaliação das pupilas e da Escala de Coma de Glasgow (GCS), melhorava a detecção precoce de complicações neurológicas no pós-operatório. Métodos: Projetamos um estudo observacional, prospectivo, de dois grupos de pacientes submetidos à neurocirurgia eletiva: craniotomia (Grupo C) e não craniotomia (Grupo NC). Analisamos a concordância e a razão de chance (OR) de alterações nas escalas neurológicas e no BIS na sala de recuperação pós-anestesia (SRPA) para complicações neurológicas no pós-operatório. Comparamos a avaliação isolada das pupilas e da GCS (pupilas-GCS) com todas as escalas de avaliação neurológica e o BIS (escalas-BIS). Resultados: No Grupo C (n = 70), 16 pacientes (22,9%) apresentaram complicações neurológicas na SRPA. As escalas-BIS registraram mais alterações do que as pupilas-GCS (31,4% vs. 20%; p < 0,001), foram mais sensíveis (94% vs. 50%) e permitiram uma estimativa mais precisa das complicações neurológicas na SRPA (p = 0,002; OR = 7,15, IC 95% = 2,1-24.7 vs. p = 0,002; OR = 9,5, IC 95% = 2,3-39,4). No grupo NC (n = 46) não houve complicações neurológicas na SRPA. As escalas-BIS mostraram alterações em 18 casos (39,1%) versus um caso (2,2%) com as pupilas-GCS (p < 0,001). Alteração na CNS na admissão à SRPA aumentou o risco de complicações neurológicas na enfermaria (p = 0,048; OR = 7,28, IC 95% = 1,021-52,006). Conclusões: Aplicados em conjunto, avaliação das pupilas, GCS, escala de Ramsay, CNS, Nu-DESC e BIS melhoraram a detecção precoce de complicações neurológicas no pós-operatório na SRPA após craniotomias eletivas.

Benefit of general anesthesia monitored by bispectral index compared with monitoring guided only by clinical parameters. Systematic review and meta-analysis / Benefício da anestesia geral com monitoração do índice bispectral em comparação com o monitoramento guiado apenas por parâmetros clínicos. Revisão sistemática e metanálise

Abstract Background: The bispectral index parameter is used to guide the titration of general anesthesia; however, many studies have shown conflicting results regarding the benefits of bispectral index monitoring. The objective of this systematic review with meta-analysis is to evaluate the clinical impact of monitoring with the bispectral index parameter. Methods: The search for evidence in scientific information sources was conducted during December 2013 to January 2015, the following primary databases: Medline/PubMed, LILACS, Cochrane, CINAHL, Ovid, SCOPUS and TESES. The criteria for inclusion in the study were randomized controlled trials, comparing general anesthesia monitored, with bispectral index parameter with anesthesia guided solely by clinical parameters, and patients aged over 18 years. The criteria for exclusion were studies involving anesthesia or sedation for diagnostic procedures, and intraoperative wake-up test for surgery of the spine. Results: The use of monitoring with the bispectral index has shown benefits reducing time to extubation, orientation in time and place, and discharge from both the operating room and post anesthetic care unit. The risk of nausea and vomiting after surgery was reduced by 12% in patients monitored with bispectral index. Occurred a reduction of 3% in the risk of cognitive impairment postoperatively at 3 months postoperatively and 6% reduction in the risk of postoperative delirium in patients monitored with bispectral index. Furthermore, the risk of intraoperative memory has been reduced by 1%. Conclusion: Clinically, anesthesia monitoring with the BIS can be justified because it allows advantages from reducing the recovery time after waking, mainly by reducing the administration of general anesthetics as well as the risk of adverse events.

Resumo Justificativa: O parâmetro índice bispectral (BIS) é usado para guiar a titulação da anestesia geral; no entanto, muitos estudos têm mostrado resultados conflitantes quanto aos benefícios da monitoração do BIS. O objetivo desta revisão sistemática com metanálise foi avaliar o impacto clínico da monitoração do parâmetro BIS. Métodos: A busca por evidências em fontes de informação científicas foi conduzida de dezembro de 2013 a janeiro de 2015 nas seguintes bases de dados: Medline/PubMed, Lilacs, Cochrane, Cinahl, Ovid, Scopus e Teses. Os critérios de inclusão foram estudos randomizados e controlados, que compararam anestesia geral monitorada com o parâmetro BIS com anestesia guiada apenas por parâmetros clínicos em pacientes com mais de 18 anos. Os critérios de exclusão foram estudos que envolveram anestesia ou sedação para procedimentos de diagnóstico e teste de despertar no intraoperatório de cirurgia da coluna vertebral. Resultados: O uso de monitoração com o BIS mostrou benefícios como a redução do tempo de extubação, orientação no tempo e no espaço, alta da sala de cirurgia e da sala de recuperação pós-anestesia. O risco de náuseas e vômitos no pós-operatório foi reduzido em 12% em pacientes monitorados com o BIS. Ocorreu uma redução de 3% no risco de disfunção cognitiva em três meses do pós-operatório e 6% no risco de delírio pós-operatório em pacientes monitorados com o BIS. Além disso, o risco de despertar com memória intraoperatória foi reduzido em 1%. Conclusão: Clinicamente, a monitoração com o BIS pode ser justificada, pois permite vantagens como reduzir o tempo de recuperação, principalmente, a administração de anestésicos gerais e o risco de eventos adversos.

Variables Influencing the Depth of Conscious Sedation in Plastic Surgery: A Prospective Study

BACKGROUND: Conscious sedation has been widely utilized in plastic surgery. However, inadequate research has been published evaluating adequate drug dosage and depth of sedation. In clinical practice, sedation is often inadequate or accompanied by complications when sedatives are administered according to body weight alone. The purpose of this study was to identify variables influencing the depth of sedation during conscious sedation for plastic surgery. METHODS: This prospective study evaluated 97 patients who underwent plastic surgical procedures under conscious sedation. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, and glucose levels were measured. Midazolam and ketamine were administered intravenously according to a preset protocol. Bispectral index (BIS) recordings were obtained to evaluate the depth of sedation 4, 10, 15, and 20 minutes after midazolam administration. Associations between variables and the BIS were assessed using multiple regression analysis. RESULTS: Alcohol intake and female sex were positively associated with the mean BIS (P<0.01). Age was negatively associated with the mean BIS (P<0.01). Body mass index (P=0.263), creatinine clearance (P=0.832), smoking history (P=0.398), glucose (P=0.718), AST (P=0.729), and ALT (P=0.423) were not associated with the BIS. CONCLUSIONS: Older patients tended to have a greater depth of sedation, whereas females and patients with greater alcohol intake had a shallower depth of sedation. Thus, precise dose adjustments of sedatives, accounting for not only weight but also age, sex, and alcohol consumption, are required to achieve safe, effective, and predictable conscious sedation.

Bispectral index monitoring in patients undergoing open heart surgery

Abstract Introduction: To obtain the optimal anesthesia depth is not easy in cardiovascular surgery patients where the haemodynamic reserve is limited, due to reasons such as not being able to give the desired dose of anesthetic agent, or the change in the pharmacokinetics of the agent in the heart-lung machine. This study was planned to assess the contribution of bispectral index (BIS) monitoring in the depth of anesthesia. Methods: The patients were divided into 2 groups, and BIS monitoring was used for each patient. Group 1 (G1 n=35): keeping the BIS monitor screen open, the anesthesia need was set. Group 2 (G2 n=35): BIS monitor was tied to the patient and the monitor screen was closed in such a way that the anaesthesist couldn't see the BIS value. When the recording time came, the data on the monitor was recorded. The need for the anesthetic agent was set according to the parameters such as haemodynamics or follow up of pupils, instead of BIS value, by titrating the anesthetic infusion doses. Results: BIS values were similar in both groups before the induction, BIS values in both groups showed a decrease, showing no significant statistical difference (P>0.05). One patient in each group said that he dreamt, and one patient in G2 said that he had heard a noise and felt that he was taken from one place to another. Conclusion: The management should be done with clinical evaluation, haemodynamics and other monitorization methods and BIS monitoring findings together.

Comparison of sevoflurane concentration for insertion of proseal laryngeal mask airway and tracheal intubation in children (correlation with BIS) / Comparação da concentração de sevoflurano para a inserção de ML proseal e intubação traqueal em crianças (correlação com BIS)

BACKGROUND: Sevoflurane is an inhalational agent of choice in paediatric anaesthesia. For management of airways in children a suitable alternative to ETT is a paediatric proseal laryngeal mask airway (benchmark second generation SAD). Various studies have shown that less sevoflurane concentration is required for LMA insertion in comparison to TI. BIS is a useful monitor of depth of anaesthesia. AIMS: To compare concentration of sevoflurane (end tidal and MAC value) required for proseal laryngeal mask airway insertion and tracheal intubation in correlation with BIS index. METHOD: The prospective randomised single blind study was done in children between 2 and 9 years of ASA I and II and they were randomly allocated to Group P (proseal laryngeal mask airway insertion) and Group TI (tracheal intubation). No sedative premedication was given. Induction was done with 8% sevoflurane and then predetermined concentration was maintained for 10 min. Airway was secured either by proseal laryngeal mask airway or endotracheal tube without using muscle relaxant. End tidal sevoflurane concentration, MAC, BIS, and other vital parameters were monitored every minute till insertion of an airway device. Insertion conditions were observed. Statistical analysis was done by ANOVA and Students t test. RESULTS: Difference between ETLMI (2.49 ± 0.44) and ETTI (2.81 ± 0.65) as well as MACLMI (1.67 ± 0.13) and MACTI (1.77 ± 0.43) was statistically very significant, while BISLMI (49.05 ± 10.76) and BISTI (41.25 ± 3.25) was significant. Insertion conditions were comparable in both the groups. CONCLUSION: We can conclude that in children airway can be secured safely with proseal laryngeal mask airway using less sevoflurane concentration in comparison to tracheal intubation and this was supported by BIS index.

JUSTIFICATIVA: Sevoflurano é um agente inalatório de escolha em anestesia pediátrica. Para o manejo de vias aéreas em crianças, uma opção adequada para o TET é uma MLP pediátrica (referência de segunda geração SAD). Vários estudos mostraram que uma menor concentração do sevoflurano é necessária para a inserção da ML em comparação com a IT. O BIS é um monitor útil da profundidade da anestesia. OBJETIVOS: Comparar a concentração de sevoflurano (valores no fim da expiração e da CAM) necessária para a inserção de MLP e intubação traqueal em correlação com o BIS. MÉTODO: Estudo prospectivo, randômico e cego conduzido com crianças entre 2-9 anos, estado físico ASA I-II, randomicamente alocados nos grupos P (inserção de MLP) e IT (intubação traqueal). Pré-medicação sedativa não foi administrada. A indução foi feita com sevoflurano a 8% e, em seguida, a concentração predeterminada foi mantida durante 10 minutos. A via aérea foi garantida por MLP ou tubo endotraqueal, sem o uso de relaxante muscular. A concentração de sevoflurano no fim da expiração, CAM, BIS e outros parâmetros vitais foram monitorados a cada minuto até a inserção do dispositivo respiratório. As condições de inserção foram observadas. A análise estatística foi feita com o teste t de Student e Anova. RESULTADOS: As diferenças entre TEIML (2,49 ± 0,44) e TEIT (2,81 ± 0,65), bem como CAMIML (1,67 ± 0,13) e CAMIT (1,77 ± 0,43), foram estatisticamente muito significativas; enquanto BISIML (49,05 ± 10,76) e BISIT (41,25 ± 3,25) foram significativos. As condições de inserção foram comparáveis em ambos os grupos. CONCLUSÃO: Podermos concluir que a MLP em comparação com a intubação traqueal pode ser segura para a via aérea de crianças com o uso de menos concentração de sevoflurano, o que foi confirmado pelo BIS.

A loading dose of 1 µg/kg and maintenance dose of 0.5 µg/kg/h of dexmedetomidine for sedation under spinal anesthesia may induce excessive sedation and airway obstruction

BACKGROUND: For many drugs, dosing scalars such as ideal body weight (IBW) and lean body mass are recommended over the use of total body weight (TBW) during weight-based dose calculations. Doses based on TBW are frequently used, and this may cause under- or over-dosing. Because dexmedetomidine (DEX) overdosing could increase the incidence of side effects, and spinal anesthesia may increase sensitivity to a sedative agent, determining an appropriate dose is critical. METHODS: Eighty patients were randomly divided into 2 groups, the IBW and TBW groups. Patients received a loading dose of DEX 1 µg/kg IBW or TBW for 10 min, followed by a continuous infusion at 0.5 µg/kg/h IBW or TBW after the induction of spinal anesthesia. The patients' vital signs, bispectral index (BIS), peripheral capillary oxygen saturation, time to reach a BIS of 80, airway obstruction score, and coughing were monitored and recorded at 0, 10, 30, and 50 min after the start of the loading dose injection. RESULTS: The changes in BIS, airway obstruction score, the incidence of side effects, and time to reach a BIS of 80 did not show statistically significant differences between the two groups. However, airway obstruction and/or coughing occurred in both groups, and the average BIS in both groups was lower than the target BIS of 60-80 at 30 and 50 min. CONCLUSIONS: A loading dose of DEX 1 µg/kg for 10 min, and a maintenance dose of DEX 0.5 µg/kg/h of either IBW or TBW, may induce excessive sedation, airway obstruction, and/or coughing under spinal anesthesia.

Effects of bispectral index monitoring as an adjunct to nurse-administered propofol combined sedation during colonoscopy: a randomized clinical trial

BACKGROUND/AIMS: The efficacy of bispectral index (BIS) monitoring during colonoscopic sedation is debated. We aimed to determine whether BIS monitoring was useful for propofol dose titration, and to evaluate differences in sedative administration between expert and inexperienced medical personnel during colonoscopy procedures that required moderate sedation. METHODS: Between February 2012 and August 2013, 280 consecutive patients scheduled to undergo a screening colonoscopy participated in this study and were randomly allocated to the expert or inexperienced endoscopist group. Each group was further divided into either a BIS or a modified Observer's Assessment of Alertness/Sedation Scale (MOAA/S) subgroup. Trained nurses administered combined propofol sedation and monitored sedation using either the BIS or MOAA/S scale. RESULTS: The mean BIS value throughout the procedure was 74.3 +/- 6.7 for all 141 patients in the BIS group. The mean total propofol dose administered in the BIS group was higher than that in the MOAA/S group, independently of the endoscopists' experience level (36.9 +/- 29.6 and 11.3 +/- 20.7, respectively; p < 0.001). The total dose of propofol administered was not significantly different between the inexperienced endoscopist group and the expert endoscopist group, both with and without the use of BIS (p = 0.430 and p = 0.640, respectively). CONCLUSIONS: Compared with monitoring using the MOAA/S score alone, BIS monitoring was not effective for titrating the dose of propofol during colonoscopy, irrespective of colonoscopist experience.

Anesthetic Experience of Spinal Anesthesia after Sedation in Un-cooperated Elderly Patients

Regional anesthesia is mostly used in operations on the lower abdomen or lower extremities in elderly patients. It shows nearly no difference in long-term outcomes compared to general anesthesia, but it is used more often because of the several advantages. However, during the regional anesthetic procedures, the patient must cooperate and has to be lateral decubitus position without physical movement. Therefore, in the case of the patients who are not cooperated, it may be not easy to perform regional anesthesia. In this study, we present 3 case reports that regional anesthesia after sedation is performed in un-cooperated patients. Regional anesthesia after sedation may be a good method to improve outcomes in un-cooperated elderly patients.