Efecto de los anestésicos en la electroencefalografía. Parte 2 / Effect of anesthetics on electroencephalography. Part 2

Resumen: La anestesiología cuenta con una nueva generación de monitores de la profundidad anestésica como Narcotrend, SedLine y el índice biespectral; con un procesador del electroencefalograma llamado espectrograma o espectrografía. Tras la obtención del electroencefalograma, se procesa para graficar en tres dimensiones: la frecuencia, el tiempo y la potencia en una escala de colores, con lo que se obtiene la matriz de densidad espectral (DSA, por sus siglas en inglés). El objetivo de esta revisión narrativa es ilustrar los efectos de los anestésicos más comunes en el espectrograma y hacer una breve revisión de su huella en el electroencefalograma.

Abstract: Anesthesiology has a new generation of anesthetic depth monitors such as Narcotrend, SedLine and Bispectral Index; with an electroencephalogram processor called a spectrogram or spectrograph. After obtaining the electroencephalogram, it is processed to graph three dimensions: frequency, time, and power on a color scale, obtaining the DSA (density spectral array). The objective of this narrative review is to illustrate the effects of the most common anesthetics on the spectrogram and to briefly review their signature on the electroencephalogram.

Viabilidade e validade do índice bispectral para mensurar o sono de pacientes na unidade de terapia intensiva / Viability and validity of the bispectral index to measure sleep in patients in the intensive care unit

RESUMO Objetivo: Investigar a viabilidade do índice bispectral na avaliação do sono de pacientes criticamente enfermos lúcidos e a associação entre os parâmetros do sono aferidos por esse índice, pelo Questionário de Sono de Richards-Campbell e pelo ruído ambiental. Métodos: Estudo observacional transversal que avaliou indivíduos adultos criticamente enfermos com doenças de gravidades baixa ou moderada. Foram aferidos: volume e tempo total de sono, volume e tempo de sono profundo, volume e tempo de sono contínuo, latência para o início do sono e pressão sonora ambiental. A percepção subjetiva do sono foi registrada com o Questionário de Sono de Richards-Campbell nas manhãs subsequentes às noites de observação. Resultados: Os pacientes apresentaram tempo total de sono reduzido (234 minutos), predominância dos estágios superficiais e pouco sono profundo (1,7 minutos). Os volumes de sono total, profundo e contínuo foram 3.679, 9,4 e 3.143 índice bispectral versus minutos, respectivamente. A latência para o sono foi de 94 minutos. O escore médio do Questionário de Sono de Richards-Campbell foi 57,9. Foram observadas correlações de magnitudes fracas entre volume total, tempo total, volume contínuo e os domínios do Questionário de Sono de Richards-Campbell profundidade do sono, qualidade geral de sono e escore total; e correlações de magnitudes moderadas entre volume total, tempo total, volume contínuo e o domínio ocorrência de despertares. Conclusão: O índice bispectral é um instrumento com viabilidade limitada para monitorar o sono de pacientes lúcidos e com enfermidades de gravidades baixa e moderada na unidade de terapia intensiva, e pacientes que apresentaram maior volume, tempo total e volume de sono contínuo tiveram melhor percepção global do sono.

Abstract Objective: To investigate the viability of the bispectral index in the sleep evaluation of critically ill patients and to quantify the associations of sleep parameters measured by this index with the Richards-Campbell Sleep Questionnaire and environmental noise. Methods: This was a cross-sectional observational study that evaluated critically ill adults with diseases of low or moderate severity. The following were measured: total sleep volume and time, deep sleep volume and time, continuous sleep volume and time, sleep onset latency, and environmental sound pressure level. The subjective perception of sleep was evaluated with the Richards-Campbell Sleep Questionnaire the morning after each night of observation. Results: Patients had a low total sleep time (234 minutes), a predominance of superficial sleep stages, and little deep sleep (1.7 minutes). The total, deep, and continuous sleep volumes were 3,679, 9.4, and 3,143 (bispectral index units × minutes), respectively. The sleep latency was 94 minutes. The mean score of the Richards-Campbell Sleep Questionnaire was 57.9. Total sleep volume, total sleep time, and continuous sleep volume were weakly correlated with the Richards-Campbell Sleep Questionnaire depth of sleep domain score, overall sleep quality domain score, and total score. Total volume, total time, and continuous volume were moderately correlated with the occurrence of awakenings domain score. Conclusion: The bispectral index is an instrument with limited viability to monitor the sleep of lucid patients and patients with low to moderate disease severity in the intensive care unit. Patients with higher total sleep volume, total sleep time, and continuous sleep volume had better overall sleep perception.

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.

The effect of bispectral index monitoring on cognitive performance following sedation for outpatient colonoscopy: a randomized controlled trial

ABSTRACT BACKGROUND: Bispectral index (BIS) monitoring can positively affect cognitive performance through decreasing the use of sedative agents. We aimed to evaluate the effect of BIS monitoring on early cognitive performance among patients undergoing sedation for colonoscopy. DESIGN AND SETTING: Randomized, controlled trial in a university hospital. METHODS: 100 patients were randomized into two groups. In the monitored group (n = 50), the depth of anesthesia was monitored using the BIS, and BIS scores were maintained between 60 and 80. In the usual care group (n = 50), BIS monitoring was not performed. To determine the patients' baseline cognitive performance levels, the mini-mental state examination (MMSE), Trieger dot test (TDT) and clock drawing test (CDT) were used. The patients' post-procedure cognitive performance levels were determined when they were classified as ready for discharge. RESULTS: The total volume (mg) of propofol used [median (range) IQR] in the sedation procedure was lower in the monitored group [100 (50-200) 100-140] than in the usual care group [150 (75-200) 100-200] (P < 0.001). The discharge scores [mean (SD)] using MMSE and CDT were higher in the monitored group [26 (3) and 3 (1), respectively] than in the usual care group [23 (3) and 2 (1), respectively] (P = 0.002 and P = 0.002, respectively). The discharge scores using TDT [mean (SD)] were lower in the monitored group [11 (7)] than in the usual care group [15 (11)] (P = 0.033). CONCLUSION: BIS monitoring among sedated patients was associated with lower propofol use and smaller decline in cognitive performance. CLINICAL TRIAL REGISTRATION: This trial was registered in the Australian New Zealand Clinical Trial Registry (ACTRN12617000134325).

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.

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.

Application of early goal-directed sedation with bispectral index in sedation management of severe patients in ICU / 中国医师杂志

Objective The bispectral index (BIS) was introduced into the sedation strategy of critical patients in intensive care unit (ICU) and replaced the Richmond agitation sedation scale (RASS).The ventilation time,ICU length of stay,and 90-day mortality were compared between the two groups of patients who performed early goal-directed sedation (EGDS) or standard traditional directed sedation (STDS) strategies.Methods A prospective controlled study of severe patients with mechanical ventilation ≥48 h in ICU (20 cases from April 2016 to May 2017,46 cases from June 2017 to April 2018) were randomly divided into EGDS or STDS group.There were no significant differences in age,gender,and acute physiology and chronic health evaluation score Ⅱ (APACHE Ⅱ) score between the two groups in the two periods.The correlation between RASS and BIS was analyzed in the first period.The BIS of the patients in a RASS range of (-2-1) was 73.65 ± 7.87 in the EGDS group,and that of RASS range of (-3--1) was 64.14 ± 7.25 in the STDS group.The above BIS was applied to the two sedation strategies in the second period respectively.The ventilation time,ICU length of stay,and 90-day mortality were recorded.Results There was no significant difference in the ventilation time between the two groups [(164.12 ± 137.96) h and (155.33 ±64.86)h,P =0.08].ICU length of stay of the EGDS group was longer than that of the STDS group.The 90-day mortality of the EGDS group was higher than that of the STDS group.Conclusions Correlations between RASS and BIS were found in this study,and BIS can be used for sedation assessment in ICU patients.Large sample study is still needed to compare EGDS and STDS with BIS.

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

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.

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.

Uso de monitorizacion cerebral para el despertar intraoperatorio / The use of cerebral monitoring for intraoperative awareness

Introduction: the bispectral index monitoring system (BIS) was introduced in the United States in 1994 and approved by the FDA in 1996 with the objective of measuring the level of consciousness through an algorithm analysis of the electroencephalogram (EEG) during general anesthesia. This novelty allowed both the surgeon and the anesthesiologist to have a more objective perception of anesthesia depth. The algorithm is based on different EEG parameters, including time, frequency, and spectral wave. This provides a non-dimensional number, which varies from zero to 100; with optimal levels being between 40 and 60. Objectives: Perform an analysis of the advantages and limitations of the anesthetic management with the bispectral index monitoring, specifically for the management and prevention of intraoperative awareness. Methodology: A non-systematic review was made from literature available in PubMed between the years 2001 and 2015, using keywords such as "BIS", "bispectral monitoring", "monitoreo cerebral", "despertar intraoperatorio", "recall" and "intraoperative awareness". Results: A total of 2526 articles were found, from which only the ones containing both bispectral monitoring and intraoperative awareness information were taken into consideration. A total of 68 articles were used for this review. Conclusion: BIS guided anesthesia has documented less immediate postoperative complications such as incidence of postoperative nausea/vomit, pain and delirium. It also prevents intraoperative awareness and its complications.

Introducción: El índice de monitoreo biespectral (BIS) fue introducido en Norte América en 1994 y aprobado por la FDA en 1996 con el objetivo de medir el nivel de conciencia realizando un análisis algorítmico del electroencefalograma (EEG) durante la anestesia general. Esta novedad permitió que tanto el cirujano como el anestesiólogo tuvieran una percepción más objetiva de la profundidad anestésica. El algoritmo está basado en diferentes parámetros del EEG, incluyendo tiempo, frecuencia y onda espectral. Esto provee un número no dimensional, que varía desde cero, hasta 100; siendo los niveles óptimos entre 40 y 60. Objetívos: Realizar un análisis de las ventajas y limitaciones del manejo anestésico con el monitor de análisis biespectral, específicamente en el manejo y prevención del despertar intraoperatorio. Metodología: Se realizó una revisión no sistemática de literatura disponible en PubMed entre los años 2001-2015, utilizando palabras clave como "BIS", "bispectral monitoring" "moni-toreo cerebral", "despertar intraoperatorio" "recall" y "intraoperative awareness". Resultados: Se encontraron un total de 2526 artículos, de los cuales solo se tomaron en cuenta aquellos que contenían información de tanto monitoria biespectral como despertar intraoperatorio. Un total de 68 artículos fueron utilizados para esta revisión. Conclusión: En la anestesia guiada por BIS se han documentado menores complicaciones postoperatorias inmediatas como la incidencia de nausea/vómito, dolor y delirium. Además de prevenir el despertar intraoperatorio y sus complicaciones.

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.

Avaliação da memória sob anestesia venosa total / The assessment of memory under total intravenous anesthesia / Evaluación de la memoria bajo anestesia venosa total

JUSTIFICATIVA E OBJETIVOS: Neste estudo, objetivamos avaliar a memória implícita e explícita em pacientes submetidos à cirurgia abdominal sob anestesia venosa total (AVT) com propofol e remifentanil, na qual o nível de anestesia foi controlado pelo monitoramento do índice bispectral (BIS). MÉTODO: Anestesia venosa total foi administrada a 60 pacientes adultos para obter níveis de BIS de 40-60. Os pacientes foram randomicamente divididos em três grupos, de acordo com as gravações que ouviram. Os pacientes do grupo categoria (CT) ouviram uma fita gravada contendo cinco nomes de animais. Os pacientes do grupo recordar palavras (RP) ouviram uma fita gravada contendo cinco palavras de frequência média na língua turca, depois de adaptadas. Os pacientes do grupo controle (GC) ouviram os sons do mar até o fim da cirurgia. Duas horas após a cirurgia, os testes foram administrados a cada paciente na sala de recuperação para avaliar a memória. RESULTADOS: Houve uma diferença entre os escores dos grupos CT e GC no Miniexame do Estado Mental (MMSE); todos os escores foram > 20. Os resultados dos testes de categoria e recordar palavras, aplicados para avaliar a memória implícita, não foram estatisticamente diferentes entre os grupos. Não houve evidência de memória implícita em nenhum dos pacientes. Um paciente lembrou-se de ouvir "o som de água" como uma prova de memória explícita. Onze pacientes declararam não ter sonhado. CONCLUSÕES: Apesar de não termos encontrado nenhuma evidência de memória implícita sob anestesia adequada com AVT, um paciente apresentou memória explícita. Embora a profundidade adequada da anestesia fornecida pelo monitoramento do BIS corrobore nossos resultados para a memória implícita, ela não explica os resultados para a memória explícita.

BACKGROUND AND OBJECTIVES: In this study, we aimed to assess implicit and explicit memory in patients who had abdominal surgery under total intravenous anesthesia (TIVA) with propofol and remifentanil, in which anesthesia level was controlled by bispectral index (BIS) monitoring. METHOD: Total intravenous anesthesia was administered to 60 adult patients, to obtain BIS levels of 40-60. Patients were randomly allocated to three groups according to tapes they listened to. Patients in the category group (CT) listened to a tape containing five animal names. Patients in the word recognition group (WM) listened to a tape containing five intermediate-frequency words, adapted into Turkish. Patients in the control group (CG) listened to sea sounds until the end of surgery. Two hours after surgery, tests were administered to each patient in the recovery room to assess memory. RESULTS: There was a difference between the CT and CG groups in their Mini-Mental State Examination scores, all values were > 20. The results of the category and word recognition tests that were applied to assess implicit memory were not statistically different among the groups. There was no evidence of implicit memory in any of the patients. One patient remembered hearing 'the sound of water' as a proof of explicit memory. Eleven patients said they had dreamt. CONCLUSIONS: Although no evidence of implicit memory under adequate anesthesia with TIVA was found, one patient showed explicit memory. Although adequate depth of anesthesia provided by BIS monitoring supports our implicit memory results, it does not explain the explicit memory results.

JUSTIFICATIVA Y OBJETIVOS: En este estudio evaluamos la memoria implícita y explícita en pacientes sometidos a la cirugía abdominal bajo anestesia venosa total (AVT), con propofol y remifentanilo, en la cual el nivel de anestesia fue controlado por el monitoreo del índice bispectral (BIS). MÉTODO: Anestesia venosa total que fue administrada a 60 pacientes adultos para obtener niveles de BIS de 40-60. Los pacientes fueron aleatoriamente divididos en tres grupos de acuerdo con las grabaciones que oyeron. Los pacientes del grupo categoría (CT) oyeron una cinta grabada que contenía cinco nombres de animales. Los pacientes del grupo recordar palabras (RP), escucharon una cinta grabada que contenía cinco palabras de frecuencia media en lengua turca, después de haber sido adaptadas. Los pacientes del grupo control (GC) oyeron los sonidos del mar hasta el final de la cirugía. Dos horas después de la cirugía, los test fueron administrados a cada paciente en la sala de recuperación para evaluar la memoria. RESULTADOS: Hubo una diferencia entre las puntuaciones de los grupos CT y GC en el Mini Examen del Estado Mental (MMSE) y todas las puntuaciones fueron > 20. Los resultados de los test de categoría y recordar palabras aplicados para evaluar la memoria implícita no fueron estadísticamente diferentes entre los grupos. No hubo evidencia de memoria implícita en ninguno de los pacientes. Un paciente recordó escuchar "el sonido del agua" como una prueba de memoria explícita. Once pacientes dijeron que no habían soñado. CONCLUSIONES: A pesar de no haber encontrado ninguna evidencia de memoria implícita bajo anestesia adecuada con AVT, un paciente tuvo memoria explícita. Aunque la profundidad adecuada de la anestesia suministrada por el monitoreo del BIS corrobore nuestros resultados para la memoria implícita, ella no explica los resultados para la memoria explícita.

Avaliação farmacodinâmica e análise físico-química de duas formulações de propofol usadas em infusão alvo-controlada / Pharmacodynamic evaluation and physical/chemical analysis of two formulations of propofol used in target-controlled infusion / Evaluación farmacodinámica y análisis físico-químico de dos formulaciones de propofol usadas en infusión objeto-controlada

JUSTIFICATIVA E OBJETIVOS: Existem várias formulações de propofol para uso clínico à disposição do anestesiologista. O objetivo desse estudo foi analisar as propriedades físico-químicas, o efeito farmacodinâmico e a equivalência farmacêutica e clínica do fármaco referência de propofol e uma formulação similar. MÉTODOS: Dezesseis voluntários participaram desse estudo aleatório, duplamente encoberto e pareado entre as formulações Diprivan® e Propovan®. As formulações foram administradas em regime de infusão alvo-controlada com concentração-alvo de 3,0 µg.mL-1 por 15 minutos. As variáveis estudadas foram a área sob a curva (ASC) do gráfico do índice bispectral (BIS) em relação ao tempo, o BIS mínimo atingido e o tempo para tal e o tempo de recuperação. As duas formulações foram submetidas às análises de tamanho de partículas da emulsão lipídica, potencial de superfície e quantificação de princípio ativo. RESULTADOS: Não houve diferença entre as formulações quando se comparou a ASC, BIS mínimo atingido e o tempo decorrido para tal. O tempo de recuperação com a formulação similar foi menor em relação à referência (oito e 10 min, respectivamente, p = 0,014). O tamanho médio de partículas da emulsão lipídica, potencial de superfície e a quantificação de princípio ativo foram semelhantes nas duas formulações. CONCLUSÃO: Não houve diferença clínica significativa entre o uso de propofol referência Diprivan® e seu similar Propovan® durante a infusão. Entretanto, o tempo de recuperação foi mais prolongado com o fármaco referência. Embora as análises com as duas formulações estudadas mostrarem resultados semelhantes quanto a sua caracterização físico-química, outros estudos devem ser realizados para justificar tal diferença.

BACKGROUND AND OBJECTIVES: There are several formulations of propofol available to the anesthesiologist for clinical use. The aim of this study was to analyze the physicochemical properties, pharmacodynamic effect, and pharmaceutical and clinical equivalence of the reference drug propofol as well as a similar formulation. METHOD: Sixteen volunteers were enrolled in this randomized, double-blind, and paired study of Diprivan® and Propovan® formulations. Formulations were given as target-controlled infusion with target concentration of 3.0 μg.mL-1 for 15 minutes. Variables studied were the area under the curve (AUC) of the bispectral index (BIS) graph regarding time, minimum BIS reached and time to reach it, and recovery time. The two formulations were sent to analysis of particle size of lipid emulsion, surface potential, and active principle quantification. RESULTS: There was no difference between the formulations when comparing AUC, minimum BIS reached and time to reach it. The similar formulation recovery time was lower compared to the reference formulation (eight and 10 min, respectively, p = 0.014). Mean particle size of lipid emulsion, surface potential, and active ingredient quantification were similar for both formulations. CONCLUSION: There was no clinically significant difference between the use of propofol, reference Diprivan®, and the similar Propovan® during infusion. However, the recovery time was longer with the reference drug. Although analysis of both formulations studied show similar results regarding its physicochemical characterization, further studies should be conducted to justify this difference.

JUSTIFICATIVA Y OBJETIVOS: Existen varias formulaciones de propofol para el uso clínico que están disponibles para el anestesiólogo. El objetivo de este estudio, fue analizar las propiedades físico-químicas, el efecto farmacodinámico y la equivalencia farmacéutica y clínica del fármaco referencia de propofol y una formulación similar. MÉTODO: Dieciséis voluntarios participaron en este estudio aleatorio, doble ciego y pareado entre las formulaciones Diprivan® y Propovan®. Las formulaciones fueron administradas en un régimen de infusión objeto-controlada con una concentración objetivo de 3,0 µg.mL-1 durante 15 minutos. Las variables estudiadas fueron el área bajo la curva (ASC) del gráfico del índice bispectral (BIS) con relación al tiempo, el BIS mínimo alcanzado y el tiempo para tal, y el tiempo de recuperación. Las dos formulaciones se sometieron a los análisis de tamaño de partículas de la emulsión lipídica, potencial de superficie y cuantificación del principio activo. RESULTADOS: No hubo diferencia entre las formulaciones cuando se comparó la ASC, el BIS mínimo alcanzado y el tiempo transcurrido para tal. El tiempo de recuperación con la formulación similar fue menor con relación a la referencia (8 y 10 min, respectivamente, p = 0,014). El tamaño promedio de partículas de la emulsión lipídica, potencial de superficie y la cuantificación del principio activo, fueron similares en las dos formulaciones. CONCLUSIONES: No hubo diferencia clínica significativa entre el uso de propofol referencia Diprivan® y su similar Propovan® durante la infusión. Sin embargo, el tiempo de recuperación se extendió más con el fármaco de referencia. Aunque los análisis de las formulaciones estudiadas muestren resultados similares en cuanto a su caracterización físico-química, otros estudios deben ser realizados para justificar tal diferencia.

The determinants of propofol induction time in anesthesia / 대한마취과학회지

BACKGROUND: The required dose of anesthetics is generally smaller in patients with low cardiac output (CO). A high CO decreases the blood concentration of anesthetics during induction and maintenance of anesthesia. However, a high CO may also shorten the delivery time of anesthetics to the effect site, e.g. the brain. We assessed the time required for induction of anesthesia with propofol administered by target-controlled infusion (TCI), and investigated factors that modify the pharmacodynamics of propofol. METHODS: After measuring CO and blood volume (BV) by dye densitometry, propofol was infused using TCI to simulate a plasma concentration of 3 microg/ml. After infusion, the time taken to achieve bispectral index (BIS) values of 80 and 60 was determined. Age, sex, lean body mass (LBM), and cardiovascular parameters were analyzed as independent variables. The dependent variables were the time taken to achieve each BIS value and the plasma concentration of propofol (Cp) 10 min after the commencement of infusion. RESULTS: Multiple regression analysis revealed that a high CO significantly reduced the time taken to reach the first end point (P = 0.020, R2 = 0.076). Age and LBM significantly prolonged the time taken to reach the second end point (P = 0.001). Cp was negatively correlated with BV (P = 0.020, R2 = 0.073). CONCLUSIONS: Cardiac output was a statistically significant factor for predicting the time required for induction of anesthesia in the initial phase, whereas, age and LBM were significant variables in the late phase. The pharmacodynamics of propofol was intricately altered by CO, age, and LBM.

Awake during General Anesthesia with BispectralIndex Value of 35

Awareness of intraoperative events in patients under general anesthesia is rare, but awareness during anesthesia is a serious complication that leads to anxiety and post-traumatic stress disorder. The Bispectral Index (BIS) has generally been accepted as a measurement of hypnosis under anesthesia. It is derived from a processed electroencephalogram and computer algorithm that assigns a numerical value based on the probability of consciousness. A 46-year-old, 65-kg male without underlying disease underwent elective surgery for ventral hernia. The patient in this case was administered an anesthetic that we frequently use and then average BIS value are 35. But he experienced awake during general anesthesia. We describe the first case of intraoperation awake under BIS 40 using desflurane.

Anestesia intravenosa total en cirugía de tumor carotídeo / Total intravenous anesthesia in carotid surgery tumor

Mujer de 18 años operada en junio del 2011 por el Servicio de Cabeza y Cuello del Hospital Nacional Arzobispo Loayza, por una tumoración cervical izquierda. La tomografía en fase angiográfica mostró un tumor estadio Shamblin III en bifurcación carotidea. Programada para exeresis de glomus carotídeo y ante los antecedentes de secuelas neurológicas postquirúrgicas de este estadio, se elige la técnica de anestesia intravenosa total con propofol, modo infusión controlada por objetivo, por sus propiedades de protección cerebral, e infusión de remifentanilo. Se monitorizó profundidad anestésica continua con índice biespectral. En el transoperatoio se lacera carótida común, se clampa la arteria durante 5 horas con liberación intermitente al cabo distal para evidenciar circulación cerebral colateral. Se coloca bypass con injerto de safena externa y se realiza exeresis final de tumor. Paciente hemodinámicamente estable, pasa a la unidad de recuperación con Ramsay y luego de 11 horas de anestesia.

Female, 18 years old, operated in June 2011 by Servicio de Cabeza y Cuello del Hospital Nacional Arzobispo Loayza, because of a left cervical tumor. The angiography phase of the CT scan showed a carotid bifurcation tumor Shamblin III stage. Scheduled for exeresis of carotid glomus and aware of the fact of postoperative neurological sequelae of this stage tumor, we choose the total intravenous anesthesia technique with propofol in target controlled infusion, because of its brain protective properties, and infusion of remifentanil. Depth of anesthesia was monitors continuously with bispectral index. Common carotid artery was lacerated during surgery, and it was clamped for 5 hours with intermittent release of the distal stump to asses collateral cerebral circulation. A bypass with saphenous graft was placed and the tumor exeresis was performed. A stabled patient went to the recovery unit with Ramsay 52 after 11 hours of anesthesia.

Índice bispectral e outros parâmetros processados do eletroencefalograma: uma atualização / Bispectral index and other processed parameters of electroencephalogram: an update

JUSTIFICATIVA E OBJETIVOS: A análise processada do eletroencefalograma tornou-se de extrema importância na monitoração do sistema nervoso, sendo utilizada a fim de uma melhor adequação anestésica. O objetivo foi fazer uma revisão sobre cada um dos parâmetros processados, definindo sua real importância. CONTEÚDO: Foi realizada revisão mostrando os aspectos matemáticos, físicos e clínicos assim como suas correlações e atualizações, com apresentação de novos parâmetros integrados. CONCLUSÕES: A análise adequada dos parâmetros processados do eletroencefalograma pode proporcionar maior segurança intraoperatória assim como resultar em melhor desfecho para o paciente.

BACKGROUND AND OBJECTIVES: The processed analysis of electroencephalogram became extremely important to monitor nervous system, being used to obtain a better anesthetic adequacy. The objective was to conduct a review about each processed parameter, defining its real importance. CONTENT: A review was conducted showing mathematical, physical and clinical aspects as well as their correlations and updates, presenting new integrated parameters. CONCLUSIONS: An adequate analysis of processed parameters of electroencephalogram may provide more intraoperative safety as well as result in a better outcome for the patient.

JUSTIFICATIVA Y OBJETIVOS: El análisis procesado del electroencefalograma se convirtió en algo extremadamente importante en el monitoreo del sistema nervioso, siendo utilizado para lograr una mejor adecuación anestésica. El objetivo fue realizar una revisión sobre cada uno de los parámetros procesados, definiendo su real importancia. CONTENIDO: Se realizó una revisión mostrando los aspectos matemáticos, físicos y clínicos, como también sus correlaciones y actualizaciones, y presentando nuevos parámetros integrados. CONCLUSIONES: El análisis adecuado de los parámetros procesados del electroencefalograma, puede proporcionar una mayor seguridad intraoperatoria como también un mejor resultado para el paciente.

The Significance of Sedation Control in Patients Receiving Mechanical Ventilation / 결핵및호흡기질환

BACKGROUND: Adequate assessment and control of sedation play crucial roles in the proper performance of mechanical ventilation. METHODS: A total of 30 patients with various pulmonary diseases were prospectively enrolled. The study population was randomized into two groups. The sedation assessment group (SAG) received active protocol-based control of sedation, and in the empiric control group (ECG), the sedation levels were empirically adjusted. Subsequently, daily interruption of sedation (DIS) was conducted in the SAG. RESULTS: In the SAG, the dose of midazolam was significantly reduced by control of sedation (day 1, 1.3+/-0.5 microg/kg/min; day 2, 0.9+/-0.4 microg/kg/min; p<0.01), and was significantly lower than the ECG on day 2 (p<0.01). Likewise, on day 2, sedation levels were significantly lower in the SAG than in the ECG. Significant relationship was found between Ramsay sedation scale and Richmond agitation-sedation scale (RASS; rs=-0.57), Ramsay Sedation Scale and Bispectral Index (BIS; rs=0.77), and RASS and BIS (rs=-0.79). In 10 patients, who didn't require re-sedation after DIS, BIS showed the earliest and most significant changes among the sedation scales. Ventilatory parameters showed significant but less prominent changes, and hemodynamic parameters didn't show significant changes. No seriously adverse events ensued after the implementation of DIS. CONCLUSION: Active assessment and control of sedation significantly reduced the dosage of sedatives in patients receiving mechanical ventilation. DIS, conducted in limited cases, suggested its potential efficacy and tolerability.

Reporte de casos de trastorno cognitivo postoperatorio en pacientes operados de prostatectomía radical laparoscópica / Report of cases of postoperative cognitive disorder in patients operated on laparoscopic radical prostatectomy

El presente reporte sugiere la relación entre el trastorno cognitivo postoperatorio y la tasa de supresión de electroencefalografía por índice biespectral en los pacientes operados de prostatectomia radical laparoscópica.

This report suggests the relationship between postoperative cognitive disorder and electroencephalography suppression rates by bispectral index in patients undergoing laparoscopic radical prostatectomy