Craneotomía en el paciente despierto / Awake craniotomy

Introducción: La craneotomía con el paciente despierto es útil para lograr resecciones cerebrales amplias de lesiones de áreas elocuentes. Objetivo: Presentar un caso al que se le realizó la técnica dormido- despierto. Método: Se realizó la inducción de la anestesia con propofol/fentanilo/rocuronio y se colocó una mascarilla laríngea. Después del bloqueo de escalpe se mantuvo la infusión de propofol/fentanilo y lidocaína hasta que se realizó la craneotomía. Se disminuyó la velocidad de infusión y se mantuvo de esta manera hasta finalizada la intervención. Resultados: Se logró el despertar del paciente a los 13 minutos de reducida la infusión. Se mantuvo buena estabilidad hemodinámica, sin depresión respiratoria ni otras complicaciones. El paciente se mantuvo colaborador, respondió preguntas y movilizó sus extremidades. No presentó complicaciones posoperatorias. Discusión: Dentro de las técnicas anestésicas utilizadas en el mundo la dormido- despierto-dormido es la más popular; sin embargo, constituye una alternativa no dormir nuevamente al paciente ni reinstrumentar la vía respiratoria. Los medicamentos más empleados son el propofol/remifentanilo, aunque la comparación con otros opioides no arrojan diferencias significativas; aunque sí supone un beneficio adicional la dexmedetomidina. Conclusiones: La craneotomía con el paciente despierto es posible de realizar en el entorno hospitalario siempre que exista un equipo multidisciplinario que consensue las mejores acciones médicas para el paciente(AU)

Introduction: Awake craniotomy is useful to achieve wide brain resections of lesions in eloquent areas. Objective: To present the case of a patient who was operated on with the asleep-awake-asleep technique. Method: Anesthesia was induced with propofol-fentanyl-rocuronium and a laryngeal mask was placed. After scalp block, the propofol-fentanyl and lidocaine infusion was maintained until craniotomy was performed. The infusion rate was decreased and remained this way until the end of the intervention. Results: The patient was awakened thirteen minutes after the infusion was reduced. Good hemodynamic stability was maintained, without respiratory depression or other complications. The patient remained collaborative, answered questions, and mobilized his limbs. He had no postoperative complications. Discussion: Among the anesthetic techniques used in the world, asleep-awake-asleep is the most popular. However, it is an alternative not to put the patient back to sleep or re-instrument the airway. The most commonly used drugs are propofol-remifentanil, although the comparison with other opioids does not show significant differences, except for dexmedetomidine, which does represent an additional benefit. Conclusions: Awake craniotomy is possible to be performed in the hospital setting as long as there is a multidisciplinary team that agrees on the best medical actions for the patient(AU)

Variability of anesthetic depth in total intravenous anesthesia vs balanced anesthesia using entropy indices: a randomized, crossover, controlled clinical trial / Variabilidad de la profundidad anestésica en anestesia total intravenosa vs. anestesia general balanceada usando índices de entropía. Un ensayo clínico aleatorizado, cruzado y controlado

Abstract Introduction: Total intravenous anesthesia (TIVA) and balanced anesthesia (BA) are the most commonly used anesthetic techniques. The differences are the variability of the depth of anesthesia between these techniques that might predict which one is safer for patients and presents a lower risk of intraoperative awakening. Objective: To determine whether a difference exists in the variability of depth of anesthesia obtained by response entropy (RE). Methods: A crossover clinical trial was conducted on 20 healthy patients receiving upper or lower limb ambulatory orthopedic surgery. Patients were randomly assigned to (a) target-controlled infusion of propofol using the Schnider model at a target concentration of 2.5 µg/mL for 15 minutes and a 10-minute washout, followed by sevoflurane administration at 0.8 minimal alveolar concentration (MAC) for the reminder of the surgery, or (b) the reverse sequence. Differences in the variability of the depth of anesthesia using RE were evaluated using paired t-test. Results: The treatment effect showed no significant difference in the average values of RE, during TIVA = 97.23 vs BA 97.04 (P = 0.39). Carry Over (-4.98 vs 4.08) and Period (100.3 vs 94.68) effects were not significantly different. Conclusion: The present study suggests that both anesthetic techniques are equivalent in terms of the stability of the depth of anesthesia. It is important to keep testing the determinants of the efficacy of different populations because the individual behaviors of patients might ultimately tip the scale.

Resumen Introducción: La anestesia total intravenosa (TIVA, por sus siglas en inglés) y la anestesia balanceada (AB) son las técnicas anestésicas más comúnmente utilizadas. La diferencia está en la variabilidad de la profundidad de la anestesia entre estas dos técnicas, lo cual pudiera predecir cuál es más segura para los pacientes y representar un menor riesgo de despertar intraoperatorio. Objetivo: Determinar si existe alguna diferencia en la variabilidad de la profundidad de la anestesia obtenida según los índices de entropía de respuesta (ER). Métodos: Se llevó a cabo un estudio clínico cruzado en 20 pacientes sanos que se sometieron a cirugía ortopédica ambulatoria de miembros superiores o inferiores. Los pacientes se asignaron aleatoriamente así: a) infusión controlada por objetivo (TCI, por sus siglas en inglés) de propofol, utilizando el modelo Schnider a una concentración objetivo de 2,5 µg/mL durante 15 min y un período de lavado de 10 minutos, seguido de la administración de sevoflurano a 0,8 de concentración alveolar mínima (CAM) durante el tiempo restante de la cirugía; o b) la secuencia inversa. Las diferencias en la variabilidad de la profundidad de la anestesia utilizando entropía de respuesta se evaluaron utilizando la prueba t pareada. Resultados: El efecto del tratamiento no mostró ninguna diferencia significativa en los valores promedio de entropía de respuesta (ER) durante TIVA = 97,23 vs. AB 97,04 (P = 0,39). Los efectos de arrastre (-4,98 vs. 4,08) y período (100,3 vs. 94,68) no fueron significativamente diferentes. Conclusiones: El presente estudio sugiere que ambas técnicas anestésicas son equivalentes en términos de estabilidad de la profundidad de la anestesia. Es importante continuar probando los factores determinantes de eficacia en las distintas poblaciones, ya que el comportamiento individual de cada paciente pudiera finalmente inclinar la balanza.

The relation between preoperative anxiety and awareness during anesthesia: an observational study / Relação entre ansiedade pré-operatória e consciência durante a anestesia: estudo observacional

Abstract Background: Anxiety is a state of worry caused by the anticipation of external or internal danger. Awareness During Anesthesia (ADA) is an unexpected memory recall during anesthesia. In this study, we aimed to determine the factors that affect preoperative anxiety and observe the incidence of ADA, as well as to determine the anxiety levels of these patients with a history of ADA. Methods: This study was planned to be prospective, observational, and cross-sectional. Patients in whom septoplasty was planned, who was admitted to the anesthesiology outpatients between March 2018 and September 2018, were ASA I-II, and aged 18-70 years were included in the study. The demographic characteristics of patients were recorded. The State-Trait Anxiety Inventory (STAI) was used to determine anxiety during a preoperative evaluation. The modified Brice awareness score was used simultaneously to determine previous ADA. Results: The anxiety scores of patients who were conscious during anesthesia were higher than other patients. The mean STAI score was 40.85 ± 14.8 in the 799 patients who met the inclusion criteria of this study. When the anxiety scores were compared, the scores were higher in females than in males (p < 0.05). The mean STAI score was found as 40.3 ± 13.8 in patients who dreamed during anesthesia. Conclusion: It is important to determine the anxiety levels of patients in the preoperative period to prevent the associated complications. Preoperative anxiety, besides preventing ADA, should be dealt with in a multidisciplinary manner. ADA should be carefully questioned while evaluating previous anesthesia experiences.

Resumo Justificativa: A ansiedade é um estado de preocupação causado pela expectativa de perigo externo ou interno. Consciência durante a anestesia (CDA) é a evocação imprevista da memória de eventos intranestésicos. O objetivo deste estudo foi determinar os fatores que afetam a ansiedade pré-operatória, a incidência de CDA e os níveis de ansiedade nos pacientes com antecedente de CDA. Método: O estudo foi planificado como prospectivo, observacional e transversal. Foram incluídos no estudo pacientes programados para septoplastia eletiva, admitidos ao ambulatório de anestesiologia entre Março de 2018 e Setembro de 2018, com classe funcional ASA I-II e faixa etária entre 18 e 70 anos. As características demográficas dos pacientes foram registradas. O Inventário de Ansiedade Traço-Estado (IDATE) foi utilizado para determinar a ansiedade durante a avaliação pré-operatória. Simultaneamente, o escore de consciência de Brice modificado foi usado para determinar CDA anterior. Resultados: Os escores de ansiedade dos pacientes que apresentaram CDA foram mais elevados do que de outros pacientes. A pontuação média do IDATE foi 40,85±14,8 nos 799 pacientes que obedeceram aos critérios de inclusão do estudo. Quando os escores de ansiedade foram comparados, foram maiores no sexo feminino do que no masculino (p < 0,05). O escore médio do IDATE encontrado foi 40,3±13,8 nos pacientes que relataram sonhos durante a anestesia. Conclusão: É importante determinar no pré-operatório os níveis de ansiedade dos pacientes para evitar as complicações associadas. Ansiedade pré-operatória e a prevenção de CDA devem ser tratadas com abordagem multiprofissional. A CDA deve ser cuidadosamente investigada, avaliando-se as experiências vividas pelo paciente em anestesias pregressas.

Monitorización automática de estados de sedación en señales electroencefalográficas / Automatic monitoring of sedation states in electroencephalographic signals

La anestesia general proporciona al paciente estados de inconciencia, amnesia y analgesia, sin embargo, se reportan casos de despertar intraoperatorio. Debido a la incidencia de este fenómeno y sus efectos psicosomáticos, el Centro de Estudios de Neurociencias, Procesamiento de Imágenes y Señales en la Universidad de Oriente, y el Hospital General Juan Bruno Zayas Alfonso ambos en Santiago de Cuba, Cuba, implementan una metodología que permita detectar automáticamente estados de sedación anestésica aplicando Inteligencia Artificial. Para esto se emplearon las señales registradas por el canal electroencefalográfico F4, nueve parámetros espectrales, las Máquinas de Soporte Vectorial y los Sistemas Neuro-Difusos. En el reconocimiento automático de los estados de Sedación Profunda, Moderada y Ligera se logró una Exactitud de 96.12 por ciento, 90.06 por ciento y 90.24 por ciento respectivamente con las Máquinas de Soporte Vectorial, por lo que se propone el uso del canal electroencefalográfico F4 en la detección de estados anestésicos(AU)

General anesthesia provide the patient states of unconsciousness, amnesia and analgesia, however, cases of intraoperative awareness are reported. Due to the incidence of this phenomenon and the psychosomatic effects it causes, the Neuroscience Studies Center, Images and Signals Processing at the University of Oriente, and the General Hospital Juan Bruno Zayas Alfonso both in Santiago de Cuba, Cuba, implement a methodology that allows the automatic detection of anesthetic sedation states applying Artificial Intelligence. For this, the signals recorded by the electroencephalographic channel F4, nine spectral parameters, the Support Vector Machines and the Neuro-Fuzzy Systems were used. In the automatic recognition of the Sedation States: Profound, Moderate and Mild an Accuracy of 96.12 percent, 90.06 percent and 90.24 percent respectively was achieved with the Support Vector Machines, so the use of the electroencephalographic channel F4 is proposed in the detection of anesthetic states(AU)

Intraoperative awareness as an example of the influence of cardiac output on anesthetic dosing: case report / Despertar intraoperatorio como ejemplo de la influencia del gasto cardíaco en la dosificación anestésica. Reporte de caso

Abstract A case of intraoperative awareness during ablation of pulmonary veins-one of the most widely used techniques in interventional cardiology-is discussed. An infusion of isoproterenol was administered following the ablation of ectopic foci. A few seconds after the infusion the patient experienced increased heart rate and intraoperative awareness manifested as an abrupt patient movement and bispectral index elevation. This has been described in similar procedures, following the administration of isoproterenol. In our opinion, the isoproterenol infusion caused the increased heart rate and subsequent abrupt rise in cardiac output. As an inversely proportional relationship between the propofol concentrations and cardiac output has been described, we believe that this rise in cardiac output could have favored the decline in the concentrations of propofol, leading to an intraoperative awareness episode.

Resumen Presentamos un caso de despertar intraoperatorio durante la ablación de venas pulmonares, una de las técnicas más empleadas por los cardiólogos intervencionistas. Tras la ablación de focos ectópicos se procede a la infusión de isoproterenol. Segundos después de la infusión se produce un aumento de la frecuencia cardíaca seguido de un despertar intraoperatorio traducido como un movimiento brusco del paciente y un aumento en el índice bi-espectral (BIS). Esto ha sido descrito en procedimientos similares tras la administración de isoproterenol. En nuestra opinión, la infusión de isoproterenol provocó un aumento de la frecuencia cardiaca y secundariamente del gasto cardíaco de forma brusca. Dado que se ha descrito una relación inversamente propocional entre las concentraciones de propofol y el gasto cardíaco, pensamos que este aumento del gasto cardíaco pudo condicionar un descenso de las concentraciones de propofol y esto causar el episodio de despertar intraoperatorio.

Anesthesia management by residents does not alter the incidence of recall of tracheal extubation: a teaching hospital-based propensity score analysis / A administração de anestesia por residentes não altera a incidência de memória da extubação traqueal: uma análise de pontuação de propensão baseada no ensino hospitalar

Abstract Background and objectives: The memory of emergence from anesthesia is recognized as one type of anesthesia awareness. Apart from planed awake extubation, unintentional recall of tracheal extubation is thought to be the results of inadequate anesthesia management; therefore, the incidence can be related with the experience of anesthetists. To assess whether the incidence of recall of tracheal extubation is related to anesthetists' experience, we compared the incidence of recall of tracheal extubation between patients managed by anesthesia residents or by experienced anesthetists. Methods: This is a retrospective review of an institutional registry containing 21,606 general anesthesia cases and was conducted with the board of ethical review approval. All resident tracheal extubations were performed under anesthetists' supervision. To avoid channeling bias, propensity score analysis was used to generate a set of matched cases (resident managements) and controls (anesthetist managements), yielding 3,475 matched patient pairs. The incidence of recall of tracheal extubation was compared as primary outcomes. Results: In the unmatched population, there was no difference in the incidences of recall of tracheal extubation between resident management and anesthetist management (6.5% vs. 7.1%, p = 0.275). After propensity score matching, there was still no difference in incidences of recall of tracheal extubation (7.1% vs. 7.0%, p = 0.853). Conclusion: In conclusion, when supervised by an anesthetist, resident extubations are no more likely to result in recall than anesthetist extubations.

Resumo Justificativa e objetivos: A recordação da emergência da anestesia é reconhecida como um dos tipos de memória da anestesia. Excluindo a extubação planejada com o paciente acordado, acredita-se que a memória não intencional durante a extubação traqueal seja o resultado de manejo inadequado da anestesia; portanto, a incidência pode estar relacionada com a experiência dos anestesistas. Para avaliar se a incidência de memória durante a extubação traqueal está relacionada com a experiência dos anestesistas, comparamos a incidência de memória durante a extubação traqueal entre pacientes tratados por residentes de anestesia ou por anestesistas experientes. Métodos: Estudo retrospectivo de revisão de um registo institucional com 21.606 casos de anestesia geral, conduzido com a aprovação do Comitê de Ética. Todas as extubações traqueais foram feitas por residentes sob a supervisão de anestesistas. Para evitar o viés de canalização, a análise do índice de propensão foi usada para gerar um grupo de casos pareados (manejo por residentes) e de controles (manejo por anestesistas), obtiveram-se 3.475 pares combinados de pacientes. A incidência de memória durante a extubação traqueal foi comparada com os desfechos primários. Resultados: Na população não pareada, não houve diferença na incidência de memória durante a extubação traqueal entre o manejo feito por residentes e anestesistas (6,5% vs. 7,1%, p = 0,275). Mesmo após parear os escores de propensão, não observamos diferença na incidência de memória durante a extubação traqueal (7,1% vs. 7,0%, p = 0,853). Conclusão: Em conclusão, quando supervisionadas por um anestesista, as extubações feitas por residentes não são mais propensas a resultar em memória do que as extubações feitas por anestesistas.

Uso de la Dexmedetomidina en la Neurocirugía con el paciente despierto. A propósito de un caso clínico / Use of Dexmedetomidine in Neurosurgery with the patient awake. About a clinical case

Presentamos el caso de un paciente de 58 años, coordinado para resección de tumor temporo insular izquierdo mediante una craneotomía despierto. Se analiza en este trabajo, a partir de la descripción del caso clínico, las ventajas de la resección de este tipo de lesiones con el paciente despierto. La posibilidades de abordaje, despierto durante todo el procedimiento (awake), dormido-despierto-dormido (asleep-awake-asleep), dormido-despierto (asleep-awake). A su vez se analiza la técnica anestésica, la combinación de fármacos y especialmente las características de la Dexmedetomidina. Conclusiones: la neurocirugía con el paciente despierto, determina una serie de características y desafíos para el equipo anestésico tratante y la interacción con un equipo mulitidisciplinario (neurocirujanos, neurofisiologos, anestesiologos). Existen diferentes combinaciones de fármacos; siendo la Dexmedetomidina una opción que mejorar la satisfacción de los pacientes durante la etapa de despertar, así como las condiciones quirúrgicas con mínimas interferencia en la monitorización neurofisiológica.

We present the case of a 58-year-old patient, scheduled to resection of left insular tumor by an awake craniotomy. In this paper, from the description of the clinical case, we analyzed the advantages of a resection of this type of lesion with an awake patient. We discuss the surgical approach, and options of an awake patient all throughout the procedure, asleep-awake-asleep and asleep-awake. Also, the anesthetic technique, the combination of drugs and especially the characteristics of Dexmedetomidine are analyzed. Conclusions: neurosurgery with an awake patient, determines a series of characteristics and challenges for the anesthetic and multidisciplinary team (neurosurgeons, neurophysiologists, anesthesiologists). There are different combinations of drugs, with Dexmedetomidine being an option that would improve patient satisfaction during the awakening stage, as well as surgical conditions with minimal interference in neurophysiological monitoring.

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.

Fatores de risco para o despertar intraoperatório / Risk factor for intraoperative awareness / Factores de riesgo para el despertar intraoperatorio

JUSTIFICATIVA E OBJETIVOS: O despertar intraoperatório, evento adverso na anestesia geral, pode ocorrer em cerca de 20.000 casos por ano, o que em si justifica o estudo dos fatores de risco deste evento. O objetivo deste estudo foi fazer uma revisão sobre o tema com a finalidade de diminuir a incidência do despertar intraoperatório e das sequelas psicológicas decorrentes deste incidente, que podem resultar em síndrome de estresse pós-traumático com repercussões negativas sobre o desempenho social, psíquico e funcional do paciente cirúrgico. CONTEÚ;DO: Foi realizada revisão sobre o despertar intraoperatório, avaliando suas diferentes fases durante anestesia geral, sonhos, vigília, memória explicita e implícita, assim como análise, consequências e prevenção dos principais fatores relacionados ao mesmo. CONCLUSÕES: A diminuição na incidência do despertar durante anestesia está ligada ao melhor desempenho cientifico e técnico do anestesiologista, envolvendo questões como a monitoração, a compreensão sobre os componentes da atividade anestésica, drogas hipnóticas, analgésicas, bloqueadores neuromusculares, controle de reflexos autonômicos e motores, além dos fatores de risco envolvidos neste evento.

BACKGROUND AND OBJECTIVES: The intraoperative awareness is an adverse event in the general anesthesia, and may occur in approximately 20,000 cases per year, which justifies the study of the risk factors for this event. The objective of this study was to review this subject in order to reduce the incidence of intraoperative awareness and psychological sequelae incurring from this incident, which may result in post-traumatic stress disorder with negative repercussions on the surgical patient social, psychic and functional development. CONTENT: It was conducted a review of the intraoperative awareness assessing its different phases during general anesthesia such as dreaming, wakefulness, explicit and implicit memory, as well as the analysis, consequences and prevention of its main related factors. CONCLUSIONS: The reduction of awareness incidence during anesthesia is related to the anesthesiologist improved scientific and technical performance, involving issues such as monitoring, comprehension of the anesthesia activity components, hypnotic and analgesic drugs, neuromuscular blocking agents, autonomic and motor reflex control, in addition to the risk factors involved in this event.

JUSTIFICATIVA Y OBJETIVOS: El despertar intraoperatorio, que es un evento adverso en la anestesia general, puede ocurrir en aproximadamente 20.000 casos por año, justificando, por lo tanto, el estudio de sus factores de riesgo. El objetivo de este estudio, fue hacer una revisión sobre el tema, con la finalidad de disminuir la incidencia del despertar intraoperatorio y de las secuelas psicológicas provenientes de ese incidente que pueden resultar en el síndrome de estrés postraumático con repercusiones negativas sobre el desempeño social, psíquico y funcional del paciente quirúrgico. CONTENIDO: Se hizo una revisión del despertar intraoperatorio evaluando sus diferentes fases durante la anestesia general, como el sueño, la vigilia, la memoria explicita e implícita, y también el análisis, las consecuencias y la prevención de los principales factores relacionados con el despertar. CONCLUSIONES: La reducción en la incidencia del despertar durante la anestesia, está vinculada al mejor desempeño científico y técnico del anestesiólogo, involucrando cuestiones como la monitorización, la comprensión sobre los componentes de la actividad anestésica, fármacos hipnóticos, analgésicos, bloqueantes neuromusculares, control de reflejos autonómicos y motores, además de los factores de riesgo involucrados en este evento.

Uso correto do monitor de consciência / Proper use of the monitor of consciousness

O índice bispectral (BIS) é um parâmetro multifatorial que permite a monitorização da componente hipnótico da anestesia. O BIS provê medidas quantificáveis do efeito de anestésicos no cérebro que correlacionam com a profundidade da anestesia. A monito-rização da profundidade anestésica na indução e manutenção da anestesia geral previne consciência e despertar intraoperatório, permite titular a quantidade de anestésicos adequada para promover a rápida recuperação da anestesia e evitar efeitos adversos da superdosagem dos fármacos. Desde sua introdução, a monitorização com BIS vem se tornando comum na prática anestésica. Esta revisão tem o objetivo de elucidar o papel do BIS na monitorização da hipnose na anestesia geral. Foi realizada revisão sobre o conceito de anestesia geral e monitorização da profundidade anestésica com o uso do BIS, bem como atualizações dos benefícios de seu emprego para a qualidade da anestesia, interpretação dos artefatos e drogas que podem interferir na sua utilização...

The bispectral index (BIS) is a multifactorial parameter that allows monitoring of the hypnotic component of anesthesia. The BIS provides quantitiable measures of the effect of anesthetics in the brain that correia te with the depth of anesthesia. Monitoring anesthetic depth during induction and maintenance of general anesthesia prevents intraoperative awakening and conscience and allows to holder the amount of anesthetic agents appropriate to promote a speedy recovery of anesthesia and avoid adverse effects of an overdose of drugs. Since its introduction, the BIS monitoring is becoming acommonplace in anesthetic practice. This review has the objective of elucidating the role of BIS monitor- ing in hypnosis of general anesthesia. A Literature review was conducted on the concepts of general anesthesia and monitoring of anesthetic depth using the BIS Moreover, recent articles on studies of BIS and its benetits in the quality of general anesthesia as well as the presence of artifacts and drugs that may interfere in its utilization...

Experiencias cercanas a la muerte / Near-death Experiences

Las experiencias cercanas a la muerte (ECM) son eventos lúcidos que ocurren cuando una persona está tan comprometida físicamente que moriría si su condición no lograra mejorar. Está inconsciente, sin latidos cardíacos detectables, sin respiración y los registros electroencefalográficos son planos. Las ECM pueden incluir algunos de los siguientes elementos: experiencias fuera del cuerpo o separación de la conciencia del cuerpo físico, incremento en la percepción sensorial, emociones intensas, viaje hacia o a través de un túnel, observación de una luz brillante, encuentro con seres místicos o familiares y amigos fallecidos, sentido de alteración del tiempo y el espacio, revisión de la vida, visualización de paisajes celestiales indescriptibles, encuentro con una barrera o límite, aprendizaje de un conocimiento especial y el regreso voluntario o involuntario al cuerpo físico. La similitud de las ECM en niños y adultos es una evidencia de que son reales y no debidas a creencias preexistentes, influencias culturales o experiencias previas en la vida actual. Las características de las ECM son parecidas en todo el mundo y en personas de diferentes culturas. No existen evidencias que apoyen las hipótesis psicológicas, fisiológicas, neuroquímicas y neuroanatómicas para explicar las ECM. Se han propuesto modelos multifactoriales basados en la combinación de todos los factores señalados (hipoxia cerebral, liberación de serotonina, endorfinas o compuestos similares a la ketamina). Aunque los factores fisiológicos, psicológicos y socioculturales pueden interactuar en las ECM, las hipótesis que se han propuesto son meras especulaciones sin soportes sobre lo que ocurre durante una ECM.

Near-death experiences (NDE) are lucid events that take place when a person is so physically compromised that he would die if its condition does not improve. He is unconscious, without heartbeats and breath, and with a flat-line electroencephalogram. NDE may include some of the following elements: Out of the body experiences or separation of consciousness from the physical body, increase in sensory perception and intense emotions, travel into or through a tunnel, encounter with a brilliant light and mystical beings, deceased relatives or friends, a sense of alteration in time and space, visualization of unworldly realms and a special knowledge, encounter with a barrier or boundary, and a return to the body, either voluntary or involuntary. The fact that children NDE are similar to adult NDE is an evidence that these experiences are real and not due to pre-existing beliefs, cultural influences or previous experiences in the present life. The characteristics of NDE are similar worldwide. No evidence supports the physiological, psychological, neurochemical, and neuroanatomical hypothesis proposed to explain the NDE. Multifactorial models, based on the combination of all of them (brain anoxia or hypoxia, release of serotonin, endorphins and ketamine-like compounds) have also been proposed. Although physiological, psychological, and socio-cultural factors could interact in the NDE, the hypothesis proposed consist essentially in unsupported speculations about what might be happening during the NDE.

Awareness, consecuencias de una experiencia estresante: [revisión] / Anesthesia awareness: [review]

Anesthesia awareness, or "unintended intra-operative awareness" occurs during general anesthesia, on the operating table, when a patient has not had enough general anesthetic or analgesic to prevent consciousness or waking up during surgery. According to international studies its global incidence ranges from 0.1 to 0.2 percent. Its impact on people can be as severe as other traumatic experiences such as natural disasters, violent fights or sexual abuse. The prevalence of symptoms compatible with post traumatic stress disorder can be as high as 50 percent, after experiencing the awareness phenomenon. This paper reviews the main issues of the awareness phenomenon.