Period Of Anesthesia Research Articles

A surface loop array for in vivo small animal MRI/fMRI on 7T human scanners

Small animals such as non-human primate (NHP) and rodent are valuable models in frontier neuroscience researches, and comparative research between the animal model and human is helpful to understand and reveal the functional brain circuits in cognition and underlying mechanism in psychological disease. Small animals can be trained or anesthetized to endure long-term and multiple imaging scans; however, the concomitant needs in subcortical structure and function investigations pose major challenges in, e.g. spatial resolution, scan time efficiency, spatial/temporal signal-to-noise-ratio, as well as apparatus mechanical fixation. In addition, comparative investigations across species are also expected to be conducted under similar physical environment (such as the main magnetic field strength, RF pulse shape, sequence protocols, gradient waveform, system stability, etc in MRI), in order to avoid possible deviation in signal detection under different platforms, as well as to reduce experiment complexity. We have proposed a novel 5-channel surface coil that is equipped on 7T human MRI scanners and designed for small animal structural and functional MRI. Through a series of in vivo experiments over an anesthetized rat and macaque, the presented coil shows its main characteristics in, i.e. flexible coil mounting, reduced FOV, high temporal SNR, and parallel imaging capability. Such design is able to compensate the relatively lower gradient slew rate of human scanners versus those with smaller bores, and thus effectively facilitates in vivo microscopic structural MR images being obtained within a shortened and safe period of anesthesia; besides, it also enables high-resolution functional MRI (i.e. spin-echo based) being achieved with reasonable temporal resolution, distortion level and functional contrast.

Time to Recovery of Feeding After Alveolar Bone Graft Is Associated With Postoperative Nausea and Vomiting Within 2 Hours in Children

Objective:To examine the relationship between the method of anesthesia for alveolar bone graft surgery and postoperative nausea and vomiting (PONV) based on the difference in surgical timing and to assess factors related to the postoperative quality of life.Design:Retrospective observational study.Setting:Hospital.Participants:Patients with cleft lip and palate who underwent alveolar bone graft surgery under general anesthesia. The subjects were divided into two groups based on surgical timing: secondary bone graft (SBG) and late secondary bone graft (LSBG) groups.Main Outcome Measures:Relationship between time to recovery of feeding and the types of anesthesia, PONV, and postoperative pain period.Results:The mean patient age was 9.97 ± 1.33 years in the SBG group and 15.39 ± 0.31 years in the LSBG group. In the SBG group, patients who were administered fentanyl or remifentanil had significantly higher incidence of PONV than those who were not administered these drugs. In the SBG group, the time to recovery of feeding was significantly longer in patients experiencing PONV within 2 hours or that lasted for 24 hours than in those without PONV. In the LSBG group, there was no significant difference regarding any of the above factors.Conclusions:Our results suggest that the occurrence of PONV within 2 hours or lasting for 24 hours postoperatively in school-age children prolonged the time to recovery of feeding. This indicates that the time to recovery of feeding can be predicted based on the occurrence of PONV within the first 2 hours.

颅内肿瘤术后麻醉恢复期并发颅内血肿的相关因素及护理对策

颅内肿瘤术后麻醉恢复期并发颅内血肿的相关因素及护理对策

Effect of net gas volume changes on alveolar and arterial gas partial pressures in the presence of ventilation-perfusion mismatch.

The second gas effect (SGE) occurs when nitrous oxide enhances the uptake of volatile anesthetics administered simultaneously. Recent work shows that the SGE is greater in blood than in the gas phase, that this is due to ventilation-perfusion mismatch, that as mismatch increases, the SGE increases in blood but is diminished in the gas phase, and that these effects persist well into the period of nitrous oxide maintenance anesthesia. These modifications of the SGE are most pronounced with the low soluble agents in current use. We investigate further the effect of net gas volume loss during nitrous oxide uptake on low concentrations of other gases present using partial pressure-solubility diagrams. The steady-state equations of gas exchange were solved assuming a log-normal distribution of ventilation-perfusion ratios using Lebesgue-Stieltjes integration. It was shown that under these conditions the classical partial pressure-solubility diagram must be modified, that for currently used volatile anesthetic agents the alveolar-arterial partial pressure difference is less than that predicted in the past, and that the alveolar-arterial partial pressure difference may even be reversed during uptake in the case of highly insoluble gases such as sulfur hexafluoride. Comparing this with the situation described previously for nitrogen in steady-state air breathing, we show that for nitrogen, the direction of the alveolar-arterial gradient is opposite to the direction of net gas volume movement. Although gas uptake with ventilation-perfusion inequality exceeding that when matching is optimal is shown to be possible, it is less likely than alveolar-arterial partial pressure reversal. NEW & NOTEWORTHY Net uptake of gases administered with nitrous oxide may proceed against an alveolar-arterial partial pressure gradient. The alveolar-arterial gradient for nitrogen in the steady-state breathing air depends not only on the existence of a distribution of ventilation-perfusion ratios in the lung but also on the presence of a net change in gas volume and is opposite in direction to the direction of net gas volume uptake.

Parabrachial Neurons Promote Behavior and Electroencephalographic Arousal From General Anesthesia.

General anesthesia has been used clinically for more than 170 years, yet its underlying mechanisms are still not fully understood. The parabrachial nucleus (PBN) in the brainstem has been known to be crucial for regulating wakefulness and signs of arousal on the cortical electroencephalogram (EEG). Lesions of the parabrachial complex lead to unresponsiveness and a monotonous high-voltage, and a slow-wave EEG, which are the two main features of general anesthesia. However, it is unclear whether and how the PBN functions in the process of general anesthesia. By recording the levels of calcium in vivo in real-time, we found that the neural activity in PBN is suppressed during anesthesia, while it is robustly activated during recovery from propofol and isoflurane anesthesia. The activation of PBN neurons by “designer receptors exclusively activated by designer drugs” (DREADDs) shortened the recovery time but did not change the induction time. Cortical EEG recordings revealed that the neural activation of PBN specifically affected the recovery period, with a decrease of δ-band power or an increase in β-band power; no EEG changes were seen in the anesthesia period. Furthermore, the activation of PBN elicited neural activation in the prefrontal cortex, basal forebrain, lateral hypothalamus, thalamus, and supramammillary nucleus. Thus, PBN is critical for behavioral and electroencephalographic arousal without affecting the induction of general anesthesia.

Comparison of Dexmedetomidine-Ketamine-Midazolam and Isoflurane for Anesthesia of Black-tailed Prairie Dogs (Cynomys ludovicianus).

Few studies evaluate anesthesia in black-tailed prairie dogs (Cynomys ludovicianus). Isoflurane inhalant anesthesia is used in this species most commonly, but injectable protocols are poorly described. Here we compared the physiologic effects, including anesthetic depth, vital signs, and hematologic changes, of anesthetic protocols using isoflurane or a combination of dexmedetomidine, ketamine, and midazolam in black-tailed prairie dogs. In a randomized, complete crossover study design, intact male black-tailed prairie dogs (n = 9; age, 6 mo) were anesthetized by using a combination of dexmedetomidine (0.25 mg/kg IM), ketamine (40 mg/kg IM), and midazolam (1.5 mg/kg IM). For reversal, atipamezole (0.15 mg/kg) and flumazenil (0.05 mg/kg) were administered 45 min after induction. For comparison, isoflurane was administered at 5% in 100% oxygen at 5 L/min in an anesthetic induction chamber, followed by maintenance isoflurane 2% in 2 L/min oxygen through a tight-fitting facemask for 45 min. Induction and recovery time, respiratory rate, heart rate, body temperature, SpO₂, indirect blood pressure, and reflexes were monitored every 5 min during the anesthetic period. Blood samples for venous blood gases, PCV, and refractometric total protein were obtained from the cranial vena cava at 5 min and 45 min. Both protocols appeared to achieve safe and effective anesthesia. Except for blood pressure, all vital signs differed between the 2 treatments. Isoflurane anesthesia resulted in a slightly longer induction and lower respiratory rate and body temperature but increased likelihood of absent reflexes. DKM anesthesia resulted in a faster induction and less hypothermia but also prolonged recovery and lower heart rate and SpO₂ readings. These findings suggest that isoflurane provides a more stable and consistent anesthetic plane, whereas dexmedetomidine-ketamine-midazolam anesthesia may be an effective alternative for short procedures that require fast induction and limited analgesia.

Alfaxalone for total intravenous anaesthesia in horses

ObjectiveTo determine the suitability of alfaxalone total intravenous (IV) anaesthesia in horses and concurrently evaluate infusion rates, cardiovascular effects, pharmacokinetics and the quality of the anaesthetic recovery period. Study designProspective, experimental study. AnimalsEight Standardbred horses. MethodsHorses were premedicated with IV acepromazine (0.03 mg kg–1) and xylazine (1 mg kg–1) and anaesthesia was induced with guaifenesin (35 mg kg–1) and alfaxalone (1 mg kg–1). Anaesthesia was maintained for 180 minutes using an IV infusion of alfaxalone at a rate determined by a horse’s response to a supramaximal electrical noxious stimulus. Venous blood samples were regularly collected to determine alfaxalone plasma concentrations and for pharmacokinetic analysis. Cardiopulmonary variables were monitored and the quality of the anaesthetic recovery period scored. ResultsThe median (range) alfaxalone infusion rate was 3.1 (2.4–4.3) mg kg–1 hour–1. The mean ± standard deviation plasma elimination half-life, plasma clearance and volume of distribution for alfaxalone were 41 minutes, 25 ± 6.3 mL minute–1 kg–1 and 1.6 ± 0.5 L kg–1, respectively. During anaesthesia, mean arterial blood pressure was maintained above 70 mmHg in all horses. Cardiac index reached a minimum value (68% of baseline values) immediately after induction of anaesthesia and was maintained between 74% and 90% of baseline values for the remainder of the anaesthetic protocol. Following the cessation of the alfaxalone infusion, six of eight horses exhibited muscle tremors and paddling. All horses stood without incident on the first or second attempt with a median recovery score of 4.5 (good to excellent). Conclusions and clinical relevanceAnaesthesia in horses can be maintained with an infusion of alfaxalone at approximately 3 mg kg–1 hour–1. The alfaxalone infusion rates used resulted in minimal haemodynamic changes and good recovery quality. Mean alfaxalone plasma concentration was stable over the infusion period and clearance rates were similar to previously published single-dose alfaxalone studies in horses.

Anaesthetic responses and reflexes to propofol and its combination in swine

To determine the effectiveness of propofol alone (P), and the combination of xylazine-propofol (XP), xylazineketamine (XK), xylazine-thiopentone (XT), anaesthetic protocols were studied in randomly selected 16 healthy indigenous pigs of either sexes, age 12 to 15 months and weight ranging from 12 to 16 kg. The responses of propofol and the combinations in different stages of anaesthesia were closely monitored. Various reflex responses and muscle tenacity were also observed concurrently during the period of anaesthesia. The study found the shortest (0.29±0.02 min) induction period with XT anaesthesia and the longest (2.95±0.21 min) by XK; whereas, induction of anaesthesia with P and XP was 0.4±0.08 and 0.41±0.08 min respectively. The time required for maximum depth of anaesthesia was the shortest in P (7.50±0.65 min) than the combinations. However, the anaesthetic protocol with XP produced the highest (65.25±3.30 min) duration of anaesthesia than the shortest (10.75±1.75 min) extent with P. Moreover, time to recovery from anaesthesia was higher (83.25±2.14 min) in XT and shorter (18.50±1.32 min) in P protocol. Good muscle relaxation was observed in XP, XK and XT combinations. Palpebral, conjunctival, jaw, tail and digital reflexes were almost absent in XP and XT combinations. The study concluded that propofol itself is a safe anaesthetic for short surgical interventions and its combination with xylazine is to be recommended for prolonged surgical procedures in swine.

Piezosurgical management of sealer extrusion‐associated mental nerve anaesthesia: A case report

The present report describes a case where sealer extrusion (Sealapex) occurred during root canal obturation of a left lower second premolar tooth, and the patient experienced sudden pain and followed by complete anaesthesia of the lower lip. After 3weeks of conservative therapy and an unaltered anaesthesia period, piezosurgical removal of the extruded sealer and root-end resection was performed despite the direct contact with the mental neurovascular bundle. At suture removal, 1week after surgery, there was no improvement in sensation. Two weeks after the operation, the patient reported some changes, including a short paraesthesia period alternating with anaesthesia. At the fourth post-operative week, neurosensory function recovered completely. This case represents successful use of the piezoelectric technique for mental nerve decompression and periapical surgery of a lower second premolar with close contact of the mental nerve.

Effects of small-dose remifentanil combined with index of consciousness monitoring on gastroscopic polypectomy: a prospective, randomized, single-blinded trial

BackgroundWith the development of painless diagnosis and treatment, remifentanil, a synthetic opioid agonist, is increasingly used in gastroscopy for its rapid, short-term, and potent analgesic effect. However, the dosage of remifentanil used in endoscopy is unclear. Index of consciousness (IOC) is a new anesthesia depth-monitoring indicator that can be divided into index of consciousness 1 (IOC1) and index of consciousness 2 (IOC2); IOC1 is used for estimating a patient’s sedation state, whereas IOC2 reflects analgesic depth. We hypothesized that combining with IOC1 and IOC2 monitoring may be helpful to identify an optimal remifentanil dosage in gastroscopic polypectomy.MethodsOne hundred twenty patients scheduled for gastroscopic polypectomy were enrolled and were randomly assigned to remifentanil 2 ng/mL (group R2), 4 ng/mL (group R4), or 6 ng/mL (group R6), and 40 cases were in each group. During the anesthesia period, remifentanil was kept at the initial given concentration but propofol was adjusted according to IOC1. The primary outcomes were the dosage of propofol and remifentanil. The secondary outcomes were the variety of IOC1 and IOC2, patients’ awakening time, and peri-operative adverse reactions such as hypotension, hypertension, bradycardia, tachycardia, body movements, hypoxemia, therapy interruption, nausea, vomiting, aspiration, and intra-operative awareness.ResultsWith the increasing dosage of remifentanil, the propofol dosage and patients’ awakening time decreased significantly, the morbidity of hypertension and body movements also declined, but the incidence of hypotension, bradycardia, and hypoxemia rose. In group R2, the value of IOC2 remained above 50 during the treatment. However, IOC2 dropped to below 30 at the beginning of the gastroscopy in group R6, and there was statistical difference in hypoxemia between groups R2 and R6 (P <0.05).ConclusionsWith the help of IOC monitoring, we found that a target concentration of remifentanil 4 ng/mL is comparatively ideal in patients under gastroscopic polypectomy.Trial registrationChinese Clinical Trial Register: ChiCTR-OOD-16009489, on October 19, 2016.

Effects of aroma therapy and music intervention on pain and anxious for breast cancer patients in the perioperative period

To investigate the effect of the aroma therapy and music intervention on anxious and pain for the breast cancer patients in the perioperative period and the potential mechanisms. Methods: A total of 100 breast cancer patients who received surgical treatment in the comprehensive hospitals of Hunan province were recruited for this study. Patients were assigned randomly into a control group, an aroma therapy group, a music intervention group, and a joint-therapy group (n=25 per group). The patients in the control group received regular post-surgical nursery, while the patients from other groups received aroma therapy, music intervention, or both in addition to the regular nursery. The scale of anxiety and pain were measured. The measurements were carried at three time points, namely 30 min before the surgery (T1), 30 min after the recovery period of anesthesia (T2), and 4 hours after the removal of anesthesia tubing (T3). Repeated ANOVA was used to perform statistic analysis. Results: The scale of pain was significantly increased at the post-operation (T2, T3) compared to pre-surgery (T1). The therapeutic group showed significant decrease in pain at post-operation (T3) comparing with the control group (P<0.05). The scale of anxiety was the highest at pre-surgery (T1). During anaesthesia recovery, the anxiety of patients at post-operation T2 and T3 in the therapeutic groups significantly decreased compared with the control group (P<0.05). Conclusion: Both the aroma therapy and the music therapy can decrease the stress-responsive anxiety and pain for the breast cancer patients in the perioperative period.

Analgesic Effects of Pre-induction Low-dose Ketamine on Post-tonsillectomy Patients

Background: Post-operative pain management aims to decrease pain intensity with patient comfort and to improve post-operative outcome. Multimodal analgesia is currently recommended for effective post-operative pain control with lower total doses of analgesics and fewer side effects.Objective: To compare the analgesic effect of pre-induction low-dose ketamine against conventional general anaesthesia.Materials and Methods: This prospective comparative study was conducted over a period of 12 months at Combined Military Hospital, Dhaka. Two hundred and forty patients of either sex requiring tonsillectomy were divided into two groups: conventional general anaesthesia (control group) and general anaesthesia with low-dose ketamine (ketamine group). Non-invasive blood pressure, heart rate and SpO2 were recorded at regular intervals throughout the anaesthetic period. Post-operative analgesia was provided for both the groups using pethidine intramuscularly. Time to complete operation, pain intensity, time to request for first analgesia were noted and total opioid consumption and complications, if any occurred in 24 hours post-operatively, were also recorded and addressed accordingly.Results: The demographic data and mean operation time were similar in both the groups (p&gt;0.05).Time to request for first analgesia was longer in lowdose ketamine group (mean ± SD 5.36±3.21 hours) than in control group (mean ± SD 2.49±1.53 hours) (p&lt;0.05). Total dosage of pethidine consumption over 24 hours period was less in ketamine group with satisfactory pain relief (mean ± SD 98.73±2.60 mg) than in control group (mean ± SD 142.52±3.48 mg) (p&lt;0.05). Post-operative complications were also less in ketamine group than control group (p&lt;0.05).Conclusion: The result of this study suggests that pre-induction low-dose ketamine has pre-emptive analgesic effect and reduces overall post-operative opioid requirements.J Enam Med Col 2018; 8(2): 74-79

Utilization of Ultrasound Guided Tissue-directed Cellular Implantation for the Establishment of Biologically Relevant Metastatic Tumor Xenografts.

Preclinical testing of anticancer therapies relies on relevant xenograft models that mimic the innate tendencies of cancer. Advantages of standard subcutaneous flank models include procedural ease and the ability to monitor tumor progression and response without invasive imaging. Such models are often inconsistent in translational clinical trials and have limited biologically relevant characteristics with low proclivity to produce metastasis, as there is a lack of a native microenvironment. In comparison, orthotopic xenograft models at native tumor sites have been shown to mimic the tumor microenvironment and replicate important disease characteristics such as distant metastatic spread. These models often require tedious surgical procedures with prolonged anesthetic time and recovery periods. To address this, cancer researchers have recently utilized ultrasound-guided injection techniques to establish cancer xenograft models for preclinical experiments, which allows for rapid and reliable establishment of tissue-directed murine models. Ultrasound visualization also provides a noninvasive method for longitudinal assessment of tumor engraftment and growth. Here, we describe the method for ultrasound-guided injection of cancer cells, utilizing the adrenal gland for NB and renal sub capsule for ES. This minimally invasive approach overcomes tedious open surgery implantation of cancer cells in tissue-specific locations for growth and metastasis, and abates morbid recovery periods. We describe the utilization of both established cell lines and patient derived cell lines for orthotopic injection. Pre-made commercial kits are available for tumor dissociation and luciferase tagging of cells. Injection of cell suspension using image-guidance provides a minimally invasive and reproducible platform for the creation of preclinical models. This method is utilized to create reliable preclinical models for other cancers such as bladder, liver and pancreas exemplifying its untapped potential for numerous cancer models.

Assessment of the Bilateral Block of the Trunk of the Pudendal Nerve in Cats with Urethral Obstruction

Background: Clinical care of cats with urethral obstruction is a common routine in feline clinical medicine and the re-establishment of urinary flow is essential for long-lasting correction of the pathophysiological alterations presented. For this chemical restraint is usually employed, that together with the alteration, increases the anesthetic risk of these patients. Improvement in anesthetic techniques, especially the loco-regional, may contribute to reducing the anesthetic risk of these patients and facilitate maneuvers to clear the obstruction. Thus the objective of the present study was to describe and assess the bilateral block technique of the pudendal nerve in 16 cats with urethral obstruction.Materials, Methods &amp; Results: Sixteen male crossbred cats were used, with partial or total urethral obstruction, attended at the Veterinary Hospital of the Federal University of Campina Grande, PB, Brazil. The anesthetic block of the pudendal nerve trunk was carried out by placing the local anesthetic close to the ventral foramen of the second sacral vertebra, using a 13 x 0.45 mm needle attached to a 1 mL syringe. To assess the effectiveness of the bilateral block, the analgesia promoted was assessed using the substitute (“Reaction to Palpating the Surgical Wound” of subscale 1 (pain expression) of the “Compound Multi-dimensional Scale to Assess Post Operational Pain in Cats”. This assessment was made before the bilateral block (M0) and 10 min afterwards (M1) and the scores ranged from 0 to 3. In addition, a segmental assessment of the urethra was made, where, by passing a probe the sensitivity was assessed of the urethral ostium, penile and pelvic urethra and the relaxing of the external urethral sphincter. This assessment was made at M1 and classified as present or absent. In the cases where the bilateral block was inefficient, the technique was repeated, in the same locations and at the same dose as initially administered, and a new assessment (M2) was made 10 minutes after the second administration. In 12 of the 16 patients assessed the bilateral block was made once. The following were observed in these patients at M1: reduction in the reaction to penile manipulation (P = 0.003), total relaxation of the external urethral sphincter and absence of sensitivity to passing the probe through the penile urethra (P = 0.000) and insensitivity of the ostium urethrae (P = 0.006). In the animals in which the anesthetic bilateral block was repeated (4/16) the value of p adjusted for penile manipulation was 0.05. There was no reaction to the probe passage through the ostium urethrae and the penile urethra or contraction of the external urethral sphincter in 3 of the 4 animals (P = 0.625). Considering the total number of animals assessed, the urethral obstruction of the pudendal nerve trunk, carried out one or twice, caused statistically significant (P = 0.004) insensitivity to penile manipulation, probing of the ostium urethrae and the penile urethra and total relaxation of the external urethral sphincter in 14 of the 16 animals. In three patients concomitant anesthetic bilateral block was observed of the sciatic nerve, bilateral (two animals) or unilateral (one animal).Discussion: studies on the feline pudendal nerve have demonstrated that the sensitive and motor bilateral block of this nerve is possible, as corroborated by the present study. Although an atomic study had shown the possibility of concomitant bilateral block of the sciatic nerve, and therefore, according to the authors, the technique should not be recommended, this finding did not demonstrate great clinical relevance, because in most cases the patients remained under fluid therapy throughout the anesthetic recovery period (about two hours) and therefore with restricted movement. Nevertheless, studies should be carried out to improve this technique.

Incidence, risk factors and prognosis of transient pseudosubluxation after total hip arthroplasty.

Pseudosubluxation is a transient separation of the prosthetic femoral head from the acetabular liner during the anaesthetic period after total hip arthroplasty (THA). However, little is known about the frequency, pathomechanism, risk factors or natural history. To determine the incidence, direction of the displacement, risk factors and subsequent instability of pseudosubluxation, we evaluated 1099 primary cementless THAs (943 patients), which were performed during 8 years at one institution. Immediately after THA, postoperative radiographs were obtained for all hips. If a subluxation was noted, the operated hip was examined by fluoroscope within 1 hour of the detection and repeat radiographs were taken on the postoperative day 1. The pseudosubluxation was identified in 2.6% (28/1059). All of the 28 heads subluxed anteriorly and reduced in flexion-internal rotation. In multivariate analysis: (1) operative decrease of the femoral offset (odds ratio; 1.161 (95% confidence interval [CI]; 1.077-1.251), p = 0.001); and (2) medialisation of acetabular cup (odds ratio; 3.402 (95% CI; 1.482-7.813), p = 0.009) were found as risk factors for pseudosubluxation. None of the 28 hips dislocated during 3- to 8-year follow-up. Our results provide information about the incidence, risk factors and natural history of pseudosubluxation after primary THA. Surgeons should be aware of the risk of pseudosubluxation when performing THA in patients with coxa vara, who have a large femoral offset, and in those with dysplastic or deficient acetabulum, who have a lateral centre of rotation.

Xylazine regulates the release of glycine and aspartic acid in rat brain

Abstract Introduction Xylazine, a type of α2-adrenoceptors, is a commonly used drug in veterinary medicine. Xylazine-induced changes in the content of amino acid neurotransmitters – glycine (Gly) and aspartic acid (Asp), in different brain regions and neurons were studied. Material and Methods Wistar rats were administered 50 mg/kg or 70 mg/kg of xylazine by intraperitoneal injection. In addition, in vitro experiments were conducted, in which neurons were treated with 15 μg/mL, 25 μg/mL, 35μg/mL, and 45 μg/mL of xylazine. Test methods were based on the enzyme-linked immunosorbent assays (ELISA). Results During anaesthesia, Asp levels in each brain area were significantly lower compared to the control group. Except for the cerebrum, levels of Gly in other brain areas were significantly increased during the anaesthesia period. In vitro, xylazine-related neuron secretion of Gly increased significantly compared to the control group at 60 min and 90 min. Moreover, xylazine caused a significant decrease in the levels of Asp secreted by neurons at 20 min, but gradually returned to the level of the control group. Conclusion The data showed that during anaesthesia the overall levels of Asp decreased and overall levels of Gly increased. In addition, the inhibitory effect of xylazine on Asp and the promotion of Gly were dose-dependent. Our data showed that different effects of xylazine on excitatory and inhibitory neurotransmitters provided a theoretical basis for the mechanism of xylazine activity in clinical anaesthesia.

Xylazine Regulates the Release of Glycine and Aspartic Acid in Rat Brain.

IntroductionXylazine, a type of α2-adrenoceptors, is a commonly used drug in veterinary medicine. Xylazine-induced changes in the content of amino acid neurotransmitters – glycine (Gly) and aspartic acid (Asp), in different brain regions and neurons were studied.Material and MethodsWistar rats were administered 50 mg/kg or 70 mg/kg of xylazine by intraperitoneal injection. In addition, in vitro experiments were conducted, in which neurons were treated with 15 μg/mL, 25 μg/mL, 35μg/mL, and 45 μg/mL of xylazine. Test methods were based on the enzyme-linked immunosorbent assays (ELISA).ResultsDuring anaesthesia, Asp levels in each brain area were significantly lower compared to the control group. Except for the cerebrum, levels of Gly in other brain areas were significantly increased during the anaesthesia period. In vitro, xylazine-related neuron secretion of Gly increased significantly compared to the control group at 60 min and 90 min. Moreover, xylazine caused a significant decrease in the levels of Asp secreted by neurons at 20 min, but gradually returned to the level of the control group.ConclusionThe data showed that during anaesthesia the overall levels of Asp decreased and overall levels of Gly increased. In addition, the inhibitory effect of xylazine on Asp and the promotion of Gly were dose-dependent. Our data showed that different effects of xylazine on excitatory and inhibitory neurotransmitters provided a theoretical basis for the mechanism of xylazine activity in clinical anaesthesia.

The right thalamus may play an important role in anesthesia-awakening regulation in frogs.

BackgroundPrevious studies have shown that the mammalian thalamus is a key structure for anesthesia-induced unconsciousness and anesthesia-awakening regulation. However, both the dynamic characteristics and probable lateralization of thalamic functioning during anesthesia-awakening regulation are not fully understood, and little is known of the evolutionary basis of the role of the thalamus in anesthesia-awakening regulation.MethodsAn amphibian species, the South African clawed frog (Xenopus laevis) was used in the present study. The frogs were immersed in triciane methanesulfonate (MS-222) for general anesthesia. Electroencephalogram (EEG) signals were recorded continuously from both sides of the telencephalon, diencephalon (thalamus) and mesencephalon during the pre-anesthesia stage, administration stage, recovery stage and post-anesthesia stage. EEG data was analyzed including calculation of approximate entropy (ApEn) and permutation entropy (PE).ResultsBoth ApEn and PE values differed significantly between anesthesia stages, with the highest values occurring during the awakening period and the lowest values during the anesthesia period. There was a significant correlation between the stage durations and ApEn or PE values during anesthesia-awakening cycle primarily for the right diencephalon (right thalamus). ApEn and PE values for females were significantly higher than those for males.DiscussionApEn and PE measurements are suitable for estimating depth of anesthesia and complexity of amphibian brain activity. The right thalamus appears physiologically positioned to play an important role in anesthesia-awakening regulation in frogs indicating an early evolutionary origin of the role of the thalamus in arousal and consciousness in land vertebrates. Sex differences exist in the neural regulation of general anesthesia in frogs.

SOME ASPECTS OF ANESTHETIC MANAGEMENT AND POSTOPERATIVE INTENSIVE THERAPY IN PATIENTS SUBJECTED TO KIDNEY AUTOTRANSPLANTATION DURING SURGERY FOR RETROPERITONEAL SARCOMA

The article presents a retrospective analysis of anesthesia and postoperative period of five patients to whom was used autotransplantation of the kidney as a component of an operation of removing of the retroperitoneal sarcoma. To all patients were used anesthesia according to modern concepts of multimodal anesthesia based on low-flow anesthesia with Sevoflurane, thoracic epidural analgesia with Narupin and intravenous administration of Fentanyl. The following indicators were analyzed: doses of anesthetics, hemodynamic parameters, the volume of intraoperative infusion therapy, the volume of diuresis during the operation and in the postoperative period, the duration of postoperative administration of anticoagulants, the use of antibacterial drugs, the days of patients in the intensive care unit and the number of bed days spent in Hospital. It has been shown once again that the combination of low flow anesthesia with Sevoflurane, thoracic epidural analgesia with Narupin and intravenous administration of Fentanyl is a priority in the anesthetic support of such operations. Number of bed-days spent in intensive care and inpatient. Decreases with the improvement of both surgical techniques, both intra- and postoperative management of patients.

Sevoflurane Blocks the Induction of Long-term Potentiation When Present during, but Not When Present Only before, the High-frequency Stimulation.

This study tests the hypothesis that sevoflurane blocks long-term potentiation only if it is present during the high-frequency stimulation that induces long-term potentiation. Long-term potentiation, an electrophysiologic correlate of memory, was induced by high-frequency stimulation and measured as a persistent increase in the field excitatory postsynaptic potential slope in the CA1 region. Long-term potentiation was induced in the no sevoflurane group (171 ± 58% vs. 96 ± 11%; n = 13, mean ± SD); when sevoflurane (4%) was present during the high-frequency stimulation, long-term potentiation was blocked (92 ± 22% vs. 99 ± 7%, n = 6). While sevoflurane reduced the size of the field excitatory postsynaptic potential to single test stimuli by 59 ± 17%, it did not significantly reduce the size of the field excitatory postsynaptic potentials during the 100 Hz high-frequency stimulation. If sevoflurane was removed from the artificial cerebrospinal fluid superfusing the slices 10 min before the high-frequency stimulation, then long-term potentiation was induced (185 ± 48%, n = 7); this was not different from long-term potentiation in the no sevoflurane slices (171 ± 58). Sevoflurane before, but not during, ⊖-burst stimulation, a physiologic stimulus, did not block the induction of long-term potentiation (151 ± 37% vs. 161 ± 34%, n = 7). Sevoflurane blocks long-term potentiation formation if present during the high-frequency stimulation; this blockage of long-term potentiation does not persist if sevoflurane is discontinued before the high-frequency stimulation. These results may explain why short periods of insufficient sevoflurane anesthesia may lead to recall of painful or traumatic events during surgery.