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Abstract Background Flash visual evoked potentials (FVEPs) are a reliable method for protecting visual function during spine surgery in prone position. However, the popularization and application of FVEPs remain limited due to the unclear influence of various anesthetics on FVEPs. Exploring the effects of anesthetic drugs on FVEP and establishing appropriate anesthesia maintenance methods are particularly important for promoting and applying FVEP. According to the conventional concept, inhaled narcotic drugs significantly affect the success of FVEP monitoring, FVEP extraction, and interpretation. Nonetheless, our previous study demonstrated that sevoflurane-propofol balanced anesthesia was a practicable regimen for FVEPs. Desflurane is widely used in general anesthesia for its rapid recovery properties. As the effect of desflurane on FVEP remains unclear, this trial will investigate the effect of different inhaled concentrations of desflurane anesthesia on amplitude of FVEPs during spine surgery, aiming to identify more feasible anesthesia schemes for the clinical application of FVEP. Methods/ design A total of 70 patients undergoing elective spinal surgery will be enrolled in this prospective, randomized controlled, open-label, patient-assessor-blinded, superiority trial and randomly assigned to the low inhaled concentration of desflurane group (LD group) maintained with desflurane-propofolremifentanil-balanced anesthesia or high inhaled concentration of desflurane group (HD group) maintained with desflurane-remifentanil anesthesia maintenance group at a ratio of 1:1. All patients will be monitored for intraoperative FVEPs, and the baseline will be measured half an hour after induction under total intravenous anesthesia (TIVA). After that, patients will receive 0.5 minimum alveolar concentration (MAC) of desflurane combined with propofol and remifentanil for anesthesia maintenance in the LD group, while 0.7–1.0 MAC of desflurane and remifentanil will be maintained in the HD group. The primary outcome is the N75-P100 amplitude 1 h after the induction of anesthesia. We intend to use the dual measure evaluation, dual data entry, and statistical analysis by double trained assessors to ensure the reliability and accuracy of the results. Discussion This randomized controlled trial aims to explore the superiority effect of low inhaled concentration of desflurane combined with propofolremifentanil-balanced anesthesia versus high inhaled concentration of desflurane combined with remifentanil anesthesia on amplitude of FVEPs. The study is meant to be published in a peer-reviewed journal and might guide the anesthetic regimen for FVEPs. The conclusion is expected to provide high-quality evidence for the effect of desflurane on FVEPs and aim to explore more feasible anesthesia schemes for the clinical application of FVEPs and visual function protection. Trial registration This study was registered on clinicaltrials.gov on July 15, 2022. ClinicalTrials.gov Identifier: NCT05465330.

Background: The primary aim of this essay was to explore the best fitting model in remifentanil-propofol combined administrations during esophageal instrumentation (EI) from five distinct response surface models. The secondary aim was to combine the models to give appropriate effect-site drug concentrations (Ces) range with maximal comfort and safety. Methods: The Greco, reduced Greco, Minto, Scaled C50 Hierarchy and Fixed C50 Hierarchy models were constructed to fit four drug effects: loss of response to esophageal instrumentation (LREI), loss of response to esophageal instrumentation revised (LREIR), intolerable ventilatory depression (IVD) and respiratory compromise (RC). Models were tested by chi-square statistical test and evaluated with Akaike Information Criterion (AIC). Model prediction performance were measured by successful prediction rate (SPR) and three prediction errors. Results: The reduced Greco model was the best fitting model for LREI and RC, and the Minto model was the best fitting model for LREIR and IVD. The SPRs of reduced Greco model for LREI and RC were 81.76% and 79.81%. The SPRs of Minto model for LREIR and IVD were 80.32% and 80.12%. Overlay of the reduced Greco model for LREI and Minto model for IVD offered visual aid for guidance in drug administration. Conclusion: Using proper response surface model to fit different drug effects will describe the interactions between anesthetic drugs better. Combining response surface models to select the more reliable effect-site drug concentrations range can be used to guide clinical drug administration with greater safety and provide an improvement of anesthesia precision.

Background: Spine surgery is challenging to anesthesiologist due to various factors. It is important to provide intraoperative hemodynamic stability, clear surgical field and a conscious, and pain free comfortable patient post-operative. Sevoflurane and desflurane provide rapid recovery. Dexmedetomidine provides sedation, stable, hemodynamics and analgesia. Dexmedetomidine has become an integral part of balanced anesthesia along with inhalational anesthetics in spine surgery. Aims and Objectives: Our study was done to compare recovery profile of sevoflurane and desflurane with dexmedetomidine and compare total dose of dexmedetomidine required in both the groups. Materials and Methods: Sixty ASA I-II patients undergoing spine surgery were randomly divided into two groups: Group A – Sevoflurane + Dexmedetomidine and Group B – Desflurane + Dexmedetomidine. Postoperatively, time to eye opening and extubation time was measured. The patient was shifted to post-anesthesia care unit (PACU) 10 min after extubation. Fast-track criteria (FTC) score was assessed for 1 h post-extubation in PACU. Results: Mean time to eye opening in Group A: 13.07±2.08 min which was significantly longer than in Group B: 9.17±2.23 min (P

IntroductionIn patients with severe aneurysmal subarachnoid hemorrhage (SAH) deep sedation is often used early in the course of the disease in order to control brain edema formation and thus intracranial hypertension. However, some patients do not reach an adequate sedation depth despite high doses of common intravenous sedatives. Balanced sedation protocols incorporating low-dose volatile isoflurane administration might improve insufficient sedation depth in these patients.MethodsWe retrospectively analyzed ICU patients with severe aneurysmal SAH who received isoflurane in addition to intravenous anesthetics in order to improve insufficient sedation depth. Routinely recorded data from neuromonitoring, laboratory and hemodynamic parameters were compared before and up to 6 days after initiation of isoflurane.ResultsSedation depth measured using the bispectral index improved in thirty-six SAH patients (−15.16; p = 0.005) who received additional isoflurane for a mean period of 9.73 ± 7.56 days. Initiation of isoflurane sedation caused a decline in mean arterial pressure (−4.67 mmHg; p = 0.014) and cerebral perfusion pressure (−4.21 mmHg; p = 0.013) which had to be balanced by increased doses of vasopressors. Patients required increased minute ventilation in order to adjust for the increase in PaCO2 (+2.90 mmHg; p

Background Transcranial motor evoked potentials (TcMEP) were proved to be useful during complicated spinal surgeries to prevent iatrogenic complications. The effect of anesthetic agents was comprehensively discussed in literature. We investigated a new balanced anesthetic protocol using propofol and sevoflurane in addition to continuous fentanyl infusion in which we compared values and ratios of amplitudes and latencies of TcMEP waves at different time point. Materials and Methods A total of 60 patients underwent spinal surgeries were randomly allocated into two groups who received either 75–100 µg/kg/min propofol (P group) or 25 ug/kg/min propofol and 0.2% below corrected-to-age- half MAC of sevoflurane (BA group). TcMEP was recorded before positioning (R1), after positioning (R2), and after skin incision (R3). R2/R1 and R3/R2 ratios were calculated. Modified Aldrete Score was recorded on discharge from PACU. Results Fluids infused and urine output were significantly increased in P group (p˂0.001). HR and MAP were significantly lower in P group (p˂0.001), but CVP was lower in P group at R1 and R2 (p = 0.019, 0.037). TcMEP was recorded from Vastus lateralis (VL) and Deltoid(D) muscles, which showed a significant lower amplitude in P group at different time points (p˂0.05) without significance in latencies. While when ratios were compared (L2/L1 and L3/L2), it showed significant differences (P˂0.001 and 0.041, respectively). Aldrete score was significantly higher in BA group. Conclusion Balanced regimen using propofol and sevoflurane resulted in a comparable TcMEP recording, hemodynamic stability and a better recovery from anesthesia during spinal surgeries.

Introducción. En el proceso de envejecimiento, la mayoría de los sistemas orgánicos mantienen su funcionamiento basal, pero existe una reducción de la reserva funcional y de la capacidad para compensar el estrés fisiológico, lo que hace que los pacientes de mayor edad sean más propensos a complicaciones postoperatorias. Se realizó un estudio en instituciones de Bucaramanga para determinar la incidencia de déficit cognitivo postoperatorio y los factores de riesgo asociados. Metodología. Estudio observacional analítico de cohorte prospectivo realizado en instituciones de salud de Bucaramanga durante 2017 con pacientes mayores de 55 años intervenidos bajo anestesia regional, general balanceada o anestesia total intravenosa. Resultados. Se estudiaron 173 pacientes, 112 mujeres (64.74%) y 61 hombres (35.26%) operados. Las técnicas anestésicas más empleadas fueron: Regional (46.24%) y General balanceada (44.51%). La incidencia de Déficit Cognitivo Postoperatorio a corto plazo fue 6.36% en pacientes previamente sanos, con valor P significativo (0.001) ajustado. Se detectó deterioro cognitivo del 51.41% con alteraciones en los dominios de lenguaje, atención y memoria; con aumento en la evaluación a largo plazo. Durante el seguimiento de pacientes a largo plazo resultó en un 11.55%, determinando la incidencia de Déficit Cognitivo Postoperatorio tardío en un 17.91%. La técnica anestésica con mayor proporción de déficit a largo plazo fue la anestesia mixta, comparada con anestesia regional. Discusión. En la actualidad no existe una definición estandarizada de Déficit Cognitivo Postoperatorio, se ha observado mayor frecuencia y mayor prolongación en pacientes de edad avanzada. El estudio demostró una incidencia temprana significativamente menor, comparándolo con artículos internacionales, pero una incidencia mayor en déficit postoperatorio tardío, resultado de mayores complicaciones intraoperatorias, comparado con otros estudios. Conclusiones. El Déficit Cognitivo Postoperatorio involucra múltiples factores de riesgo; en el estudio se encontró mayor asociación con la edad, la escolaridad, la hipotensión y la anestesia general. No hubo asociación entre comorbilidades y el Déficit Cognitivo Postoperatorio. Se determinó la presencia de hipotensión para desarrollo de este déficit. Cómo citar. Contreras-Forero FJ, Ochoa ME, Perez M, Pinillos M, Celis L, Valencia-Guampe JS, et al. Incidencia del déficit cognitivo postoperatorio en anestesia regional y general en una institución de cuarto nivel en bucaramanga (santander, colombia) en el año 2017. MedUNAB. 2020;23(3): 450-463. Doi: doi.org/10.29375/01237047.3711 Introduction. Within the aging process, most organic systems maintain their basal functions. However, there is a reduction in functional reserve and the capacity to compensate physiological stress, which makes older patients more prone to postoperative complications. A study was performed in institutions in Bucaramanga to determine the incidence of postoperative cognitive dysfunction and the associated risk factors. Methodology. This was a analytical observational prospective cohort study performed in healthcare institutions in Bucaramanga in 2017 with patients older than 55 years of age under regional, balanced general or total intravenous anesthesia. Results. One hundred and seventy-three operated patients were studied, among which 112 (64.74%) were women and 61 (35.26%) were men. The most commonly used anesthetic techniques were: regional (46.24%) and balanced general (44.51%). Short-term Postoperative Cognitive Dysfunction incidence was 6.36% in previously healthy patients, with an adjusted significant P value (0.001). Cognitive deterioration was detected in 51.41% of patients, with alterations in their mastery of language, attention and memory. This increased for the long-term evaluation. During long-term patient follow-up, it resulted in 11.55%, determining the incidence of delayed Postoperative Cognitive Dysfunction at 17.91%. The anesthetic technique with the highest proportion of long-term dysfunction was mixed anesthesia, compared to regional anesthesia. Discussion. There is currently no standardized definition for Postoperative Cognitive Dysfunction. It has been observed more frequently and for longer extensions in older patients. The study demonstrated a significantly lower early incidence when compared to international articles, but a greater incidence of delayed postoperative dysfunction as a result of more intraoperative complications compared to other studies. Conclusions. Postoperative Cognitive Dysfunction involves multiple risk factors. The study observed a greater association with age, level of education, hypotension and general anesthesia. There was no association between comorbidities and Postoperative Cognitive Dysfunction. The presence of hypotension was determined for developing this dysfunction. Cómo citar. Contreras-Forero FJ, Ochoa ME, Perez M, Pinillos M, Celis L, Valencia-Guampe JS, et al. Incidencia del déficit cognitivo postoperatorio en anestesia regional y general en una institución de cuarto nivel en bucaramanga (santander, colombia) en el año 2017. MedUNAB. 2020;23(3): 450-463. Doi: doi.org/10.29375/01237047.3711 Introdução. No processo de envelhecimento, a maioria dos sistemas orgânicos mantém seu funcionamento basal, mas há uma diminuição da reserva funcional e da capacidade de compensar o estresse fisiológico que torna os pacientes idosos mais sujeitos a complicações pós-operatórias. Foi realizado um estudo em instituições da cidade de Bucaramanga para determinar a incidência de déficit cognitivo pós-operatório e os fatores de risco associados. Métodos. Estudo observacional analítico de coorte prospectivo realizado em instituições de saúde em Bucaramanga durante o ano de 2017 em pacientes com idade superior a 65 anos operados sob anestesia regional, geral balanceada ou anestesia geral intravenosa. Resultados. Foram estudados 173 pacientes, 112 mulheres (64.74%) e 61 homens (35.26%) operados. As técnicas anestésicas mais utilizadas foram: regional (46.24%) e geral balanceada (44.51%). A incidência de déficit cognitivo pós-operatório de curto prazo foi de 6.36% em pacientes previamente saudáveis, com um valor P significativo (0.001) ajustado. Detectou-se deterioração cognitiva de 51.41% com alterações nos domínios da linguagem, atenção e memória; com aumento na avaliação de longo prazo. No seguimento a longo prazo dos pacientes resultou em 11.55%, determinando a incidência de déficit cognitivo pós-operatório tardio em 17.91%. A técnica anestésica com maior proporção de déficit no longo prazo foi a anestesia mista, em comparação com a anestesia regional. Discussão. Atualmente não existe uma definição padronizada de Déficit Cognitivo Pós-operatório, a qual observa-se com maior frequência e por mais tempo em pacientes idosos. O estudo demonstrou incidência precoce significativamente menor, em comparação com resultados de artigos internacionais, mas maior incidência de déficit pós-operatório tardio, resultado de maiores complicações intraoperatórias, em comparação com outros estudos. Conclusões. O Déficit Cognitivo Pós-operatório envolve múltiplos fatores de risco; o estudo encontrou maior associação com idade, escolaridade, hipotensão e anestesia geral. Não houve associação entre comorbidades e Déficit Cognitivo Pós-operatório. Determinou-se a presença de hipotensão para o desenvolvimento desse déficit. Cómo citar. Contreras-Forero FJ, Ochoa ME, Perez M, Pinillos M, Celis L, Valencia-Guampe JS, et al. Incidencia del déficit cognitivo postoperatorio en anestesia regional y general en una institución de cuarto nivel en bucaramanga (santander, colombia) en el año 2017. MedUNAB. 2020;23(3): 450-463. Doi: doi.org/10.29375/01237047.3711

Background There are several advantages of low flow anesthesia including safety, economics, and eco-friendliness. However, oxygen concentration of fresh gas flow and inspired gas are large different in low flow anesthesia. This is a hurdle to access to low flow anesthesia. In this study, we aimed to investigate the change in inhaled oxygen concentration in low flow anesthesia using oxygen and medical air. Methods A total of 60 patients scheduled for elective surgery with an American Society of Anesthesiologist physical status I or II were enrolled and randomly allocated into two groups. Group H: Fresh gas flow rate (FGF) 4 L/min (FiO₂ 0.5). Group L: FGF 1 L/min (FiO₂ 0.5). FGF was applied 4 L/min in initial phase (10 min) after intubation. After initial phase FGF was adjusted according to groups. FGF continued at the end of surgery. Oxygen and inhalation anesthetic gas concentration were recorded for 180 min at 15 min interval. Results The inspired oxygen concentration decreased by 5.5% during the first 15 min in the group L. Inspired oxygen decreased by 1.5% during next 15 min. Inspired oxygen decreased by 1.4% for 30 to 60 min. The inspired oxygen of group L is 35.4 ± 4.0% in 180 min. The group H had little difference in inspired oxygen concentration over time and decreased by 1.8% for 180 min. Conclusions The inspired oxygen concentration is maintained at 30% or more for 180 min in patients under 90 kg. Despite some technical difficulties, low flow anesthesia may be considered.

Background Transnasal Humidified Rapid Insufflation Ventilatory Exchange (THRIVE) is used to improve oxygenation, with the added benefit of a smaller increase in CO2 if self-respiration is maintained with THRIVE. Despite these advantages, the use of THRIVE through a nasal cannula is limited in situations such as epistaxis or a basal skull fracture. Case We successful used THRIVE, through the oral route under general anesthesia with spontaneous breathing in a morbidly obese patient (weight, 148 kg; height, 183 cm; body mass index, 44.2 kg/m2) who received transnasal steroid injections due to subglottic stenosis. Conclusions THRIVE through the oral route may be an effective novel option, although further studies are needed.

Few data about the electroencephalogram and its calculated indices, such as the bispectral index (BIS), have been reported in rabbits. We aimed to evaluate whether a clinically stable anesthesia was mirrored by consistent and stable BIS values and to investigate the effects of modified cerebral blood supply, due to bilateral carotid clamping and re-opening, on BIS values. We also investigated the effects of fentanyl, as an antinociceptive drug, on the BIS. Sixty-eight rabbits undergoing general anesthesia for surgical creation of carotid bifurcation aneurysms were enrolled. The BIS values were recorded at nine selected time points (TPs) during each procedure and before and after fentanyl administration. The BIS values over time were compared with two-way repeated-measures analysis of variance followed by Tukey test, while the Wilcoxon signed rank test was performed to compare values at clamping and re-opening of the carotids as well as before and after fentanyl administration. The BIS values were significantly lower during anesthesia than at the end of anesthesia and at tracheal extubation; no significant differences were found among other TPs. Adequate depth of anesthesia was mirrored by consistent BIS values among rabbits, and alteration of cerebral blood supply did not modify BIS values, except once. Following fentanyl, BIS values did not change in a clinically relevant way.

The goal of the present study was to monitor the physiological effects of a standardized balanced anesthetic protocol in brown bears (Ursus arctos) during routine dental procedures. Physiological parameters (rectal temperature, heart rate, respiratory rate and oxygen saturation) were evaluated in twelve brown bears, anesthetized with a balanced drug combination for 90 minutes during dental procedures. The animals were kept in the „Park for Dancing Bears“ Belitza, Bulgaria. A standardized premedication protocol of a combined intramuscular injection of tiletamine HCl and zolazepam HCl (Zoletil 100® Virbac, France) 1mg/kg, medetomidine HCl 0.003mg/kg and 0.05 mg/kg of butorphanol was administered intramuscularly. Anesthesia was induced intravenously with a combined bolus of ketamine at 2 mg/kg and propofol at 2 mg/kg, and maintained with a constant rate infusion (CRI) of ketamine at 0.8 mg/kg/h and propofol 0.04 at mg/kg/min. Rectal temperature decreased significantly during anesthesia, whereas: heart rate, respiratory rate and oxygen saturation were stable with no significant changes in these parameters for the duration of anesthesia. In conclusion, this anesthetic drug combination is suitable for oral surgery of medium duration in brown bears.

ABSTRACT: The aim of this study was to evaluate the bispectral index (BIS) effects in calves through continuous infusion of propofol with or without fentanyl. Eight Holstein male calves (ages from six to twelve months old) with an average weight of 123±18kg were used. All animals participated in both groups, always keeping a minimum interval of one week between the anesthetic procedures; the calves were randomly distributed between groups. Anesthesia was induced with an intravenous (IV) dose of propofol of 5mg kg-1 in control group (GP) or with propofol (4mg kg-1) associated with IV fentanyl 0.001mg kg-1(GF). All the calves were positioned in right lateral recumbency and were allowed to spontaneously breathe room air. Subsequently, the anesthesia was maintained by continuous infusion of propofol at the rate of 0.6mg kg-1 min-1 IV in GP, and associated with the infusion of fentanyl 0.001mg kg-1 hour-1 in GF. Measurements of BIS, signal quality index (SQI) and electromyography (EMG) were evaluated before anesthesia induction (TB), and at 15, 30, 45 and 60 minutes after the beginning of continuous drugs infusion (T15, T30, T45 and T60, respectively). The heart rate (HR), respiratory rate (f), end-tidal carbon dioxide tension (ETCO2) and recovery times were evaluated as well. No significant differences were observed between the groups in the BIS variables and the recovery time was longer in GF. Co-administration of propofol and fentanyl infusions, at the doses reported here, did not change the values of BIS in cattle, but delayed the recovery time.