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Purpose of review Major adverse cardiovascular and cerebrovascular events (MACCE) significantly affect the surgical outcomes. Electrocardiogram (ECG) has been a standard intraoperative monitor for 30 years. Electroencephalogram (EEG) can provide valuable information about the anesthetized state and guide anesthesia management during surgery. Whether EEG should be a standard intraoperative monitor is discussed in this review. Recent findings Deep anesthesia has been associated with postoperative delirium, especially in elderly patients. Intraoperative EEG monitoring has been demonstrated to reduce total anesthesia drug use during general anesthesia and postoperative delirium. Summary Unlike ECG monitoring, the EEG under general anesthesia has not been designated as a standard monitor by anesthesiologist societies around the world. The processed EEG technology has been commercially available for more than 25 years and EEG technology has significantly facilitated its intraoperative use. It is time to consider EEG as a standard anesthesia monitor during surgery.

Background Consciousness during surgical procedure is associated with adverse psychological effects and postoperative complications. The aim of this study is to evaluate the depth of anesthesia using brain function index (BFI) among patients undergoing elective laparotomy. Materials and methods In this cross-sectional study, 256 patients referred to (XXX) for elective laparotomy were included. BFI values using published studies were used to measure the depth of anesthesia in response to propofol, atracurium and propofol induction: deeply anesthetized (BFI Results The average dose of propofol administered/propofol infusion was 111.67 ± 78.87 and 104.88 ± 76.20, respectively, atracurium 67.04 ± 40.06 and fentanyl was 33.61 ± 9.137. Deep anesthesia and light anesthesia were significantly different at various time intervals, p Conclusion The outcomes of our study show that brain function index might be helpful to determine the level of anesthesia among patients undergoing elective laparotomy. However, further comparative studies, including other parameters are required.

Fish may warrant euthanasia for a variety of reasons, but euthanasia may be difficult to accomplish or confirm because fish can recover from deep anesthesia even after cardiac and respiratory arrest. The efficacies of three types of anesthetics were evaluated to compare their suitability for euthanasia of Unga cichlids (Sarotherodon linellii). Thirty cichlids were randomly assigned to be immersed in one of the three anesthetic solutions: tricaine methanesulfonate (MS-222), 2-phenoxyethanol (2-PE), and clove oil (CO) at doses of 1,000 mg/L, 2 mL/L, and 500 mg/L respectively. The opercular rates and caudal fin stroke rates were quantified, and the time to cessation of physiological measures (CPM) including caudal fin strokes, the reaction to external stimuli, the righting reflex, swimming, and operculation were recorded. Varying anesthetic induction times were observed with all three euthanasia solutions; the time to CPM in the 2-PE group occurred at a significantly slower rate than in the MS-222 group (P 0.05). The cost of euthanasia per cichlid was calculated, with the most economically viable option being 2-PE; at more than seven times the price of 2-PE, MS-222 was the most expensive. After a 60-min immersion in the euthanasia solution, the presence of an audible heartbeat was identified in 100% of the cichlids immersed in 2-PE, 100% immersed in CO, and 90% in MS-222, indicating that they were not reliably euthanized. Therefore, a two-step protocol is recommended in cichlids for euthanasia: heavy anesthesia via immersion followed by an intravenous or intracardiac injection of euthanasia solution, or other secondary method of euthanasia.

Neben tiefen Narkoseindexwerten wurden insbesondere Burst-Suppression-Muster und deren Zusammenhang mit postoperativem Delir und postoperativer Mortalitat untersucht. Dreizehn der im Folgenden beschriebenen Studien aus dem letzten Jahrzehnt liefern Hinweise, dass dokumentierte tiefe Narkoseindizes oder Burst-Suppression-Muster das Risiko fur entweder ein postoperatives kognitives Defizit oder die Mortalitat erhohen. Es handelt sich jedoch uberwiegend um sekundare Datenanalysen oder retrospektive Observationsstudien. Die erste prospektive Interventionsstudie zu „triple low“ konnte diesen Zusammenhang nicht nachweisen. Derzeit werden die ersten prospektiven Interventionsstudien zur Vermeidung exzessiver EEG-Suppression durchgefuhrt. Die Ergebnisse wurden nicht nur die Formulierung evidenzbasierter Empfehlungen ermoglichen, sondern sollen auch Hinweise und Anhaltspunkte liefern, ob es sich bei den oben genannten Beobachtungen um einen kausalen Zusammenhang oder ein Epiphanomen handelt.

espanolEvaluar los efectos de las nanoparticulas de luteolina en el proceso de cicatrizacion de las cavidades dentales en conejos. Diseno: Este estudio incluyo cinco conejos asignados al azar para controlar animales y animales experimentales. Inmediatamente despues de la extraccion de un incisivo maxilar superior, los alveolos alveolares de los animales experimentales se trataron con luteolina topica, mientras que los alveolos alveolares del grupo control permanecieron sin tratamiento. Los animales fueron sacrificados por decapitacion con anestesia profunda siete dias despues de la extraccion del diente. Las cavidades de los dientes se seccionaron y se tineron con hematoxilina y eosina. Resultados: la evaluacion histologica revelo que el tratamiento con luteolina indujo una curacion mas temprana de los alveolos extraidos. Conclusion: estos hallazgos sugieren que la luteolina acelera el proceso de curacion en las cuencas de los conejos. EnglishTo evaluate the effects of luteolin nanoparticles on the process tooth socket healing in rabbits. Design: This study comprised five rabbits randomly assigned to control animal and experimental animals. Immediately after the extraction of an upper maxillary incisor, the alveolar sockets of experimental animals were treated with topical luteolin while alveolar sockets of the control group remained without treatment. The animals were sacrificed by decapitation with deep anesthesia seven days post tooth extraction. The tooth sockets were sectioned and stained with hematoxylin and eosin stains. Results: Histological evaluation revealed that luteolin treatment induced earlier healing of extracted tooth sockets. Conclusion: These findings suggest that luteolin accelerates the healing process in tooth sockets of rabbits.

Previous studies have reported the usefulness of intraoperative corticocortical evoked potentials (CCEPs) for preserving language function during brain surgery.This study aimed to assess the influence of depth of anesthesia on CCEP to establish its clinical utility.Twenty patients with brain tumors or epilepsy who underwent awake craniotomy were included in this study. Before resection, the electrode plates were placed on the frontal and temporoparietal cortices, and 1-Hz alternating electrical stimuli were delivered to the pars opercularis/pars triangularis in a bipolar fashion. Electrocorticograms from the temporoparietal cortices time-locked to stimuli were averaged to obtain CCEP responses from a state of deep anesthesia until the awake state. The correlation between CCEP waveforms and bispectral index (BIS) was evaluated.CCEP amplitude increased with the increase in the BIS level. CCEP latency decreased in 5 patients and increased in 15 patients under anesthesia compared with the awake state. CCEP amplitudes decreased by 11.3% to 75.2% (median 31.3%) under anesthesia with65 BIS level. These differences were statistically significant (P0.01, Wilcoxon signed-rank test). With respect to CCEP latencies, there was no significant difference between the awake and anesthetic states.CCEP amplitudes were correlated with depth of anesthesia, whereas CCEP latencies were not affected by anesthesia. The influence of anesthesia should be considered when applying this technique to intraoperative monitoring.

Background Bispectral index (BIS) monitoring of depth of anesthesia has pioneered the field for more recent monitoring devices like the A-line ARX Index (AAI) or the state (SE) and response entropy (RE) monitoring devices. Following an observational design the present study aimed to simultaneously compare in the same patient recorded BIS, AAI and entropy values. Methods Data from patients (n = 32) undergoing minor gynecological operations were analyzed. For all patients, standardized anesthesia was used. Before induction of anesthesia AEP electrodes, BIS and entropy sensors were simultaneously placed on the forehead and recordings were started at 3 minutes before induction and continued until patient transfer to the postanesthesia care unit. Markers were set at defined landmarks. Results Anesthesia reduced mean BIS, AAI and entropy values. During uneventful, and even more pronounced, during eventful anesthesia BIS/ entropy and BIS/ AAI values showed better correlation than did AAI and entropy values. The prediction probability (Pk) of AAI (0.824 ± 0.036) and RE (0.786 ± 0.040) or SE (0.781 ± 0.040) for preanesthesia awake, postanesthesia awake or anesthesia was comparable and significantly greater than that of BIS (0.705 ± 0.047). However, only 20% of BIS, AAI and entropy values simultaneously categorized the state of the patient as awake, inadequate anesthesia, optimal anesthesia or deep anesthesia. Conclusion The prediction probability (Pk) of entropy and AAI was comparable and better than that of BIS. However, agreement between BIS, AAI and entropy measurements on patient state was poor.

Several studies have revealed that vasopressor may be more appropriate for treating intraoperative hypotension and preventing hypervolemia. This study compared the effects of vasopressor infusion and fluid supplementation on intestinal microcirculation during treating intraoperative hypotension. Thirty-two rats were randomly divided into the following four groups: Light Anesthesia group (LA, 0.8–1% isoflurane); Deep Anesthesia group (DA, 1.5–1.8% isoflurane); Fluid DA group (1.5–1.8% isoflurane and fluid supplementation); and Norepinephrine DA group (1.5–1.8% isoflurane and norepinephrine infusion). At 240 min, perfused small vessel density (PSVD) of the mucosa did not differ significantly between the Fluid DA and Norepinephrine DA groups [26.2 (3.2) vs 28.9 (2.5) mm/mm2, P = 0.077], and tissue oxygen saturation of the mucosa was lower in the Fluid DA groups than in the Norepinephrine DA groups [ 48 (7) vs 57 (6) %, P = 0.02]. At 240 min, TSVD and PSVD of the seromuscular layer were higher in the Norepinephrine DA group than in the Fluid DA group. Fluid administration was higher in the Fluid DA group than in the Norepinephrine DA group [66 (25) vs. 9 (5) μL/g, P = 0.001]. Our results showed that norepinephrine can resuscitate intraoperative hypotension related microcirculatory alteration and avoid fluid overload.

Motor activity during general anesthesia (GA) without curarization is often interpreted as reflecting insufficient analgosedation. Here we present the case of an octogenarian scheduled for deep sclerectomy receiving opioid-sparing electroencephalography-(EEG)-guided anesthesia. Periodic Leg Movements (PLM) made their appearance with ongoing surgery while his raw EEG displayed a pattern of deep GA (burst suppression). To the best of our knowledge, this is the first description of actimetry-documented persisting PLM during EEG-monitored GA. Recognizing PLM in the context of GA is of importance for anesthesiologists, as increasing sedation may increase motor activity.

Glomerular filtration rate (GFR) is considered the gold standard to test kidney function. However, the serial blood and/or urine sample collection required for the calculation of the GFR is stressful for the animal and time consuming for the experimenter. Here, we describe a transcutaneous assessment of renal function in conscious animals that does not require plasma or urine sampling and/or deep anesthesia. For the measurement, we use a near-infrared (NIR) device that records the excretion kinetic of the renal marker ABZWCY-HPβCD. ABZWCY-HPβCD is a new hydrophilic, stable, and nontoxic NIR fluorescent agent that can be used as a renal marker as it is filtrated and completely excreted through the kidneys into the urine without reabsorption or secretion and without accumulation in the skin. The data recorded in the device are then analyzed with "GFRmeasure," an open-source, freely downloadable, and user-friendly software.

In this study, we reported a new technique based on laser speckle flowgraphy to record the ocular blood flow in rabbits under deep anesthesia, and proposed parameters to characterize retinal ischemia. We applied the proposed technique to study the correlation of blood flow between the eyes of normal non-anesthetized animals, and to characterize the occlusion of the internal carotid artery (ICA) and external carotid artery (ECA). We established a correlation in blood flow between the eyes of non-anesthetized animals, and derived two new parameters, namely, the laterality index and vascular perfusion estimate (VPE). Our experimental results from 16 eyes (of 13 New Zealand white rabbits) showed a reduction in ocular blood flow with a significant decrease in the VPE after the occlusion of the ECA (p

The profound deepening of medicamentous sleep down to the burst-suppression electroencephalography pattern is used to provide medication-based protection of brain during preventive temporary clipping of the major arteries when performing surgery due to cerebral aneurysms. There is no consensus about the effect of profound suppression of electrobiological activity on the development of post-operative cognitive dysfunction. The goal: to evaluate the impact of anesthesia with the burst-suppression electroencephalography pattern on the post-operative cognitive status of the patients with no cerebral disorders. Subjects and methods. 30 patients were enrolled into the prospective randomized study, they all had surgeries due to degenerative spinal diseases. All patients were divided into two groups. Anesthesia in the main group (Group 1) differed from the one in the control group (Group 2); it included administration of propofol till achieving suppression of the electrobiological activity of burst-suppression electroencephalography pattern during 15 minutes. Prior to the surgery and in 4 days after it, all patients had neuro-psychological tests using Montreal Cognitive Assessment (MoCA), Frontal Assessment Battery (FAB) and numbers memorization techniques (NMT). Results. When testing in 4 days after surgery, results in the patients from Group 1 did not differ from pre-operative results of MoCA (Me before = 28, Me after = 28, Z = 0.714, p = 0.476), FAB (Me before = 18, Me after = 18, Z = 0.592, p = 0.554), memorization of numbers in the direct order (Me before = 18, Me after = 18, Z = 0.178, p = 0.859) and in the reverse order (Me before = 18, Me after = 18, Z = 0.548, p = 0.583). The results of the post-operative testing in Group 2 were compatible with pre-operative results of (Me before = 18, Me after = 18, Z = 0.459, p = 0.646), FAB (Me before = 18, Me after = 18, Z = 1.348, p = 0.178), memorization of numbers in the direct order (Me before = 18, Me after = 18, Z = 0.21, p = 0.843) and in the reverse order (Me before = 18, Me after = 18, Z = 0.809, p = 0.418). None of the tests detected significant differences between the Groups (U = 88, p = 0.319, Z = 0.995 for MoCA; U = 102.5, p = 0.644, Z = 0.394 for FAB; U = 92.0, p = 0.407, Z = -0.829 for memorization of numbers in the direct order, and U = 33.5, p = 0.62, Z = 0.572 for memorization of numbers in the reverse order). Conclusion. Anesthesia with burst-suppression electroencephalography pattern as a model of medication-based cerebral protection during temporary clipping of the major arteries does not cause the deterioration of cognitive status in the patients who had no cerebral pathology initially.

Purpose. This study aims to compare the effect of the depth of total intravenous anesthesia (TIVA) on intraoperative electrically evoked compound action potential (e-ECAP) thresholds in cochlear implant operations.Methods. Prospectively, a total of 39 patients aged between 1 and 48 years who were scheduled to undergo cochlear implantation surgeries were enrolled in this study. Every patient received both light and deep TIVA during the cochlear implant surgery. The e-ECAP thresholds were obtained during the light and deep TIVA.Results. After comparing the e-ECAP means for each electrode (lead) between the light and deep anesthesia, no significant differences were detected between the light and deep anesthesia.Conclusion. The depth of TIVA may have no significant influence on the e-ECAP thresholds as there was no statistical difference between the light and deep anesthesia.

The electroencephalogram (EEG) can reflect brain activity and contains abundant information of different anesthetic states of the brain. It has been widely used for monitoring depth of anesthesia (DoA). In this study, we propose a method that combines multiple EEG-based features with artificial neural network (ANN) to assess the DoA. Multiple EEG-based features can express the states of the brain more comprehensively during anesthesia. First, four parameters including permutation entropy, 95% spectral edge frequency, BetaRatio and SynchFastSlow were extracted from the EEG signal. Then, the four parameters were set as the inputs to an ANN which used bispectral index (BIS) as the reference output. 16 patient datasets during propofol anesthesia were used to evaluate this method. The results indicated that the accuracies of detecting each state were 86.4% (awake), 73.6% (light anesthesia), 84.4% (general anesthesia), and 14% (deep anesthesia). The correlation coefficient between BIS and the index of this method was 0.892 ( p &lt, 0.001 ). The results showed that the proposed method could well distinguish between awake and other anesthesia states. This method is promising and feasible for a monitoring system to assess the DoA.

Mismatch detection is the process of identification of rare stimuli from a sequence of stimuli. This important cognitive function is usually attributed to the cerebral cortex. To test the human midbrain involvement in sound mismatch detection, we recorded local field potentials in the states of deep anesthesia and clear consciousness from the drainage-electrode implanted in the cerebral aqueduct of an adult patient with an obstructive hydrocephaly who had undergone pineal region tumor removal through anterior interhemispheric transcallosal approach. We found a significant difference in the state of deep anesthesia at 256-364 ms after hearing a rarely presented sounds compared with frequently presented sounds and equally probable sounds. This difference was not found in the same experiment in the state of clear consciousness. The results suggest that human midbrain participates in mismatch detection and can do it even without cognitive activity of the cerebral cortex. Amplitude-frequency analysis of the midbrain records revealed that propofol affects the electrical activity of both human midbrain and cortex but the level of inhibition of the cortex is 6 times higher than the level of inhibition of the midbrain. We suppose that the human cortex is more susceptible to propofol than the human midbrain.

This study aims to use combined wavelet and neural network model to extract electroencephalogram (EEG) signal features during anesthesia and classify them according to the Depth of Anaesthesia (DOA). EEG signals were selected according to their Bispectral Index (BIS) value during anaesthesia and were processed using Discrete Wavelet Transform (DWT).The dimensionality of the wavelet coefficient vectors were reduced by extracting key features from their distribution. Artificial Neural networks (ANN) were implemented using the extracted features of EEG signals as inputs and then classifying anesthetic depth as awake, light anesthesia, moderate anaesthesia, deep anesthesia and very deep anaesthesia. The proposed model will classify depth of anaesthesia accurately.

Introduction Several studies have attempted to use human dental pulp stem cells (hDPSCs) for pulp-dentin complex regeneration in vitro . However, the safety of such applications should be first evaluated in vivo before their use in clinical trials. The purpose of this study was to investigate the in vivo fate of intrapulpally transplanted hDPSCs. Methods hDPSCs were isolated and cultured from impacted third molars. In vivo experiments were performed using 7-week-old male BALB/c nude mice. Under deep anesthesia, 1 × 10 5 hDPSCs were transplanted in mice via the tail vein for intravenous injection or into the pulp chamber for intrapulpal transplantation. A total of 56 mice, 28 per group, were used. Mice were sacrificed at different time points, and the numbers of hDPSCs in the organs were analyzed quantitatively. In addition, qualitative analysis was performed to detect intrapulpally transplanted hDPSCs. Results Intravenously injected hDPSCs were mostly distributed to the lungs and rarely detected in other organs at all observed time points. The hDPSCs transplanted into the pulp chamber rarely migrated to other organs over time. Conclusions These data indicate a differential distribution of transplanted hDPSCs between the intravenous and intrapulpal route and show the safety of pulpal transplantation of hDPSCs.

OBJECTIVE Motor evoked potentials (MEPs) are a critical indicator for monitoring motor function during neurological surgery. In this study, the influence of depth of anesthesia on MEP response was assessed. METHODS Twenty-eight patients with brain tumors who underwent awake craniotomy were included in this study. From a state of deep anesthesia until the awake state, MEP amplitude and latency were measured using 5-train electrical bipolar stimulations on the same site of the precentral gyrus each minute during the surgery. The depth of anesthesia was evaluated using the bispectral index (BIS). BIS levels were classified into 7 stages: < 40, and from 40 to 100 in groups of 10 each. MEP amplitude and latency of each stage were compared. The deviation of the MEP measurements, which was defined as a fluctuation from the average in every BIS stage, was also considered. RESULTS A total of 865 MEP waves in 28 cases were evaluated in this study. MEP amplitude was increased and latency was decreased in accordance with the increases in BIS level. The average MEP amplitudes in the > 90 BIS level was approximately 10 times higher than those in the < 40 BIS level. Furthermore, the average MEP latencies in the > 90 BIS level were 1.5–3.1 msec shorter than those in the < 60 BIS level. The deviation of measured MEP amplitudes in the > 90 BIS level was significantly stabilized in comparison with that in the < 60 BIS level. CONCLUSIONS MEP amplitude and latency were closely correlated with depth of anesthesia. In addition, the deviation in MEP amplitude was also correlated with depth of anesthesia, which was smaller during awake surgery (high BIS level) than during deep anesthesia. Therefore, MEP measurement would be more reliable in the awake state than under deep anesthesia.

Modern computer-based methods to monitor anesthesia are widespread. They are used in order to avoid awareness, to reduce consumption of anesthetics, to optimize recovery times and to detect prolonged times of deep anesthesia and associated immunsuppression, mortality and morbidity. This review illustrates the evidence with which these goals were achieved until now. Finally, a recommendation for each indication is given. The useage of EEG-monitoring may help to avoid awareness and allows a reduced of consumption of anesthetics. The question if a cumulated time of deep anesthesia is associated with elevated mortality might be of a certain importance in the future.

Depth of anesthesia estimation with the Electroencephalogram (EEG) is a main current challenge in anesthesia studies. This paper proposes an original method founded on combination of permutation entropy and frequency measure to calculate an index, called Brain function index (BFI), to quantify depth of anesthesia. As EEG derived features characterize different aspects of EEG signal, it would be logical to utilize multiple features to evaluate the effect of anesthetic. Such a method implemented in the Saadat brain function assessment module (Saadat Co., Tehran, Iran). The BFI and commercial RE index as employed in the Datex-Ohmeda monitor are applied to EEG signals gathered from 18 patients during sevoflurane anesthesia. The results show that both BFI and RE indices track the changes in EEG especially at deep anesthesia state. However, the BFI index makes better response about the point of loss of consciousness and it can be derived with significantly less computational complexity. Taking into account the high accuracy of this method, an innovative EEG processing device may be extended to help the anesthetists to estimate the depth of anesthesia precisely.

Objective : It is well known that electroencephalograms (EEGs) show electrical silence in deep anesthesia as well as brain death. This is the first report on intracranial EEG changes in deep anesthesia. Methods : We developed a new direct brain monitoring system capable of recording intracranial EEGs. This study included 13 patients with head trauma or cerebrovascular accident under deep anesthesia. Results : The intracranial EEGs showed different patterns of wave activity in depth compared with the cortical surface. In 3 of the cases, the scalp EEG showed a flat tracing at 2.0–2.5% of isoflurane. In two of the cases, the intracranial EEGs showed electrical silence when the scalp EEG was flat. Decreasing the concentration of isoflurane to 1.5%, the intracranial EEG showed single paroxysmal appearance of ‘revival' theta waves on the electrocorticogram (ECoG) or electroventriculogram (EVG). The intracranial ‘revival' wave was followed by high-voltage burst-waves. In another case, at 2.0–2.5% of isoflurane, the amplitude of the waves was greatest on the EVG. Conclusion : There is wave activity difference in the brain depth, which the scalp EEG is unable to show. Intracranial EEGs are able to show the first signs of revival after a nearly flat tracing in deep anesthesia.

Removal of the laryngeal mask airway (LMA) can be executed while patients are deeply anesthetized or awake. Recent publications have focused on suitable anesthetic concentrations in the brain for removal of LMA in anesthetized patients. Here, we describe an easy and safe method for removal of LMA during deep anesthesia.

Summary We report the use of dexmedetomidine for laryngoscopy, rigid bronchoscopy, and tracheal extubation in the operating room in two children who had undergone tracheal reconstruction 1 week previously. Dexmedetomidine in combination with propofol provided appropriately deep anesthesia during these brief but stimulating procedures without cardiovascular or respiratory depression.

Anorectal surgery requires deep anesthesia since this region of the body has a dense sensory nerve supply and is highly reflexogenic. Surgical procedures under light planes of anesthesia will result in intense pain, reflexive body movements, tachypnea, and even laryngeal spasm. Deep anesthesia for anorectal procedures can be achieved using different forms of anesthesia including general endotracheal, regional, or local anesthesia; local anesthesia is generally administered in conjunction with general sedation.

Accurate quantification of loss of response to external stimuli is essential for understanding the mechanisms of loss of consciousness under general anesthesia. We present a new approach for quantifying three possible outcomes that are encountered in behavioral experiments during general anesthesia: correct responses, incorrect responses and no response. We use a state-space model with two state variables representing a probability of response and a conditional probability of correct response. We show applications of this approach to an example of responses to auditory stimuli at varying levels of propofol anesthesia ranging from light sedation to deep anesthesia in human subjects. The posterior probability densities of model parameters and the response probability are computed within a Bayesian framework using Markov Chain Monte Carlo methods., National Institutes of Health (U.S.) (Grant DP2-OD006454), National Institutes of Health (U.S.) (Grant K25-NS057580), National Institutes of Health (U.S.) (Grant DP1-OD003646), National Institutes of Health (U.S.) (Grant R01-EB006385), National Institutes of Health (U.S.) (Grant R01-MH071847)

In this paper 5 methods for the assessment of signal entropy are compared in their capability to follow the changes in the EEG signal during transition from continuous EEG to burst suppression in deep anesthesia. To study the sensitivity of the measures to phase information in the signal, phase randomization as well as amplitude adjusted surrogates are also analyzed. We show that the selection of algorithm parameters and the use of normalization are important issues in interpretation and comparison of the results. We also show that permutation entropy is the most sensitive to phase information among the studied measures and that the EEG signal during high amplitude delta activity in deep anesthesia is of highly nonlinear nature.

Magnetic resonance images of rat brain were analyzed by texture analysis in order to study the effects of a nociceptive stimulation (formalin test) under propofol deep anesthesia. Changes of the texture in different cerebral brain areas acquired before and after stimulation were checked. Our statistical analysis of texture shows that these changes were present only in the amygdala, in agreement with the facts already known about the unconscious memorization of nociceptive stimuli.

Monitoring the depth of anesthesia is significant for the clinical surgery. In order to detect the depth of anesthesia (DOA), the Lempel-Ziv complexity (C(n)) analysis of electroencephalogram (EEG) of the SD rats was studied in this paper. The EEG C(n)s from different channels under different DOA were measured, and the relationship between C(n) and DOA was analyzed. The studies show that the C(n) of different channels changing with DOA have similar tendency, so it is enough to monitor DOA by one channel EEG analysis. The C(n) of EEG decreases while the depth of anesthesia increases and vice versa, it works very well in tracking rats' depth and trend of anesthesia. Two thresholds of C(n) were defined; one distinguishes awake and light anesthesia state, the other distinguishes light and deep anesthesia state. In addition, the C(n) computation is simple and fast, therefore, it may provide a practical index to monitor DOA in real-time for clinic.

Although the brain is the target organ of anesthesia, the electroencephalogram (EEG) is not routinely monitored during anesthetic procedures. This is due primarily to the difficulty of interpreting changes in the complex EEG waveform with respect to anesthetic conditions. Most attempts at developing EEG derived variables have been based on spectral analysis. In this study the EEG is examined as a non-linear dynamic system that may exhibit chaotic behavior. Using this approach the EEG signal can be characterized by its fractal dimension based on a phase space geometric reconstruction of the EEG time series. Eight human subjects were studied at three anesthetic levels (light, nominal, and deep anesthesia). The dimensionality of EEG samples from these subjects is shown to decrease with increasing anesthetic depth. This property may prove important in the classification of brain activity and may have clinical utility as a diagnostic tool. >

Survival surgeries upon chicks are commonly used in auditory research. Appropriate anesthesia is usually obtained with intramuscular or intraperitoneal injections of systemic agents. These techniques have several drawbacks, including delayed onset of anesthesia, difficulty in adjusting the dosage to accomodate individual animals' different responses, prolonged recovery times, and in some cases substantial mortality. We present a technique of administering inhaled isoflurane via an endotracheal tube which we have used for over a year with excellent results. With this agent, onset of deep anesthesia is very rapid, dosage can be titrated readily, overdosage is survivable, complete recovery occurs within a few minutes and mortality is rare. This technique may be valuable for other auditory scientists performing survival surgery in avian species.

Rats were treated by moxibustion at the point of hip muscle, and intramuscular temperature was kept at 40°C for 15 minutes. The rats were sacrificed under deep anesthesia and the muscular tissues were excised immediately, three hours and 24 hours after stimulation. Proteins were extracted from the homogenized and centrifuged tissues of the stimulated rats and control rats. Two-dimensional gel electrophoresis of the proteins was carried out. Heat-shock protein (hsp) with molecular weight of 70,000 (hsp 70), 85,000 (hsp 85) and 100,000 (hsp 100) was detected in rats sacrificed three hours after the stimulation by moxibustion. Protein patterns were analyzed and the ratios of the hsps were obtained.

We discovered that a food aversion could be conditioned in anesthetized sheep. Sheep were allowed to eat a familiar food (alfalfa-grain pellets) for 30 min, and 90 min later they were given either an intraruminal (IR) injection of water (C), an IR injection of LiCl (L), anesthesia followed by an IR injection of water (A), or anesthesia followed by an IR injection of LiCl (A+L). Induction of anesthesia was by an intraveneous injection of pentobarbitone sodium, and maintenance of deep anesthesia was by halothane. Sheep were maintained in deep anesthesia for 2 h to ensure that the effects of LiCl on the acquisition of a food aversion, which occur within about 1 h, were completed before they awakened. When tested 5 days later, sheep that received LiCl (treatments L and A+L) consumed less alfalfa-grain pellets than sheep that did not receive LiCl (treatments C and A) (241 g vs. 306 g; p = 0.057). Intake of sheep that were anesthetized (treatments A and A+L) did not differ from that of sheep that were not anesthetized (treatments C and L) (295 g vs. 252 g; p = 0.183). Nor was there an interaction between LiCl and anesthesia ( p = 0.423). Thus, we conclude that changes in preferences for foods caused by postingestive feedback occur automatically every time food is ingested (i.e., they are noncognitive), and the kind and amount of feedback is a function of the match between the food's chemical characteristics and its ability to meet the animal's current demands for nutrients.

Rapid euthanasia of laboratory rodents without the use of anesthesia is a necessary research technique whenever there is the likelihood of anesthesia or stress interfering with the chemistry of the tissues under investigation. Decapitation has long been the procedure of choice under such circumstances. Recently, however, the American Veterinary Medical Association (AVMA) panel on euthanasia recommended that decapitation be avoided on the grounds that the decapitated head may be conscious and suffering for as much as 15 seconds. The panel further recommended that if decapitation was scientifically necessary, the decapitated head be immediately immersed in liquid nitrogen. These AVMA guidelines now enjoy regulatory status; the recommendation that decapitation be avoided has thus caused considerable difficulty for all research requiring rapid, anesthesia-free collection of tissues. The scientific validity of these recommendations is consequently a matter of great practical as well as theoretical importance. The decision to discourage decapitation appears to have been based on a single literature report claiming that the EEG of the decapitated head revealed conscious suffering for more than 10 seconds (Mikeska and Klemm 1976). This review carefully examines the scientific literature on this subject. It is concluded that the report by Mikeska and Klemm of EEG activation in the decapitated head is correct, but that this phenomenon is also seen when the decapitated head is under deep anesthesia, and in normal brains under ether anesthesia or during REM sleep. Hence these findings do not demonstrate either consciousness or the perception of pain.(ABSTRACT TRUNCATED AT 250 WORDS)

The authors evaluate the results of 150 anesthesias of rabbits in experimental surgery employing various operations. The use of Alfathesin leads to rapid and deep anesthesia with awakening occurring in very good conditions. The technique is particularly recommended for short operations. Satisfactory cardiovascular and respiratory conditions can be maintained by tracheal intubation together with artificial ventilation, which allows for long and difficult surgical procedures.

My purpose was to evaluate the hypothesis that the pneumotaxic center could continue to regulate ventilatory activity in deep anesthesia. In decerebrate cats, the respiratory pattern was reversibly altered from eupnea to apneusis by cooling the rostral pons. Such cooling markedly changed phrenic activity even after doses of halothane, pentobarbital, or chloralose-urethane had almost entirely eliminated this activity in eupnea. It is concluded that both pontile and medullary mechanisms control eupneic ventilatory activity in unanesthetized as well as deeply anesthetized preparations.

Strabismus surgery requires neither protimes follows the procedure. Any reduction longed nor deep anesthesia but it does de­ mand that the operative field be as free as possible from obstruction by anesthesia equipment. Manipulation of the extraocular muscles during strabismus surgery may pre­ cipitate the oculocardiac reflex which, if un­ checked, can lead to cardiac arrest. This paper deals with the management of morbidity, mortality and anesthesia-related problems in ocular muscle surgery.

As long as the placenta or a part of the placenta remains within the birth passages, strict aseptic precautions must be maintained. The medical attendant, likewise, never should leave his patient until the placenta is expelled and the danger of postpartum hemorrhage has passed. Artificial expression of the retained but separated placenta is indicated as soon as the signs of separation are detected. One hour after the birth of the child, a retained but separable placenta should be artificially separated and expressed by means of the Crede procedure. A partially separated placenta, likewise should be completely separated by the Crede maneuver whenever bleeding during the third stage becomes excessive. If the Crede procedure is unsuccessful in either circumstance, manual removal of the placenta is indicated. Before attempting to separate the placenta by external manipulations, therefore, aseptic preparations for a manual removal always should be made, in order that the latter operation may be done with the minimum risk if the unsuccessful Crede procedure greatly increases the hemorrhage. Deep anesthesia is required to relax the rigid ring of an hour-glass uterus before a separated but incarcerated placenta can be removed. Adherent but inseparable placenta, placenta accreta, is accompanied by a very high maternal mortality, when the ordinary methods of treatment are employed. These poor results may be improved considerably by a more general use of hysterectomy for this rare complication.

While observations on vitamin A deficiency in the dog have been reported by several investigators,1-4 no attempt to determine the dog's minimum requirement of vitamin A has appeared in the literature. This report deals with such a study.The synthetic vitamin A-free milk previously described5 was used in these experiments. In that report5 illustrations are given of xerophthalmia produced with this synthetic milk and cured by the addition of Carotene to this diet.In this group of puppies herein reported, the curative method was used. All the puppies used were started on the vitamin A-free ration at weaning, or at most, 1 or 2 weeks later. It has been found highly important to rid the animals of any intestinal parasites at the beginning of the experiment. All the animals were devocalized under deep anesthesia. The total number of puppies used was 31.The first curative levels used were based on the curative dose per 100 gm. of body weight of the albino rat. The negative results obtained with these levels resu...

Halsey and Lemann1 found that hypodermic injection of epinephrin in asthmatic patients may cause relaxation of the bronchial musculature without synchronous rise in blood pressure. This observation reopened the question of the differing sensitivity of various epinephrin receptors. C. A. Dragstedt and Huffman2 recorded in dogs the simultaneous effects of continuous intravenous injections of epinephrin on blood pressure and intestinal motility during and after anesthesia and in the absence of drugs and anesthetics. Except under deep anesthesia, the authors were able to obtain definite blood pressure rises without intestinal inhibitions. Durant and McNinch3 externalized the spleens of two young dogs by the Barcroft-Stephens method and took blood pressure and oncometric (spleen) tracings while the animals were unanesthetized. Intravenous injection of minimal amounts of epinephrin produced blood pressure rise and splenic constriction, but no intestinal inhibition.Luckhardt and Koppanyi4 developed a method whic...