Delayed Emergence from Anesthesia: What We Know and How We Act

Postoperative delirium risk in patients with hyperlipidemia: A prospective cohort study

STUDY OBJECTIVE

Hyperlipidemia and postoperative delirium (POD) significantly affect patients' quality of life; however, the question of whether hyperlipidemia constitutes a risk factor for POD remain unclear. This study aimed to investigate whether patients with hyperlipidemia face elevated risks of developing POD and to identify potential causes for this increased risk.

DESIGN

A prospective cohort study.

SETTING

Operating room.

PATIENTS

Patients were adults scheduled for colorectal cancer surgery in 2023.

EXPOSURES

The exposure factor was hyperlipidemia, and the patients were divided into hyperlipidemia group and non-hyperlipidemia group.

MEASUREMENTS

POD occurrence within three days post-surgery was assessed using the 3-Minute Diagnostic Interview for Confusion Assessment Method. Over one year, these patients were monitored through telephone to evaluate their survival and cognitive function. Logistic regression analysis was performed to evaluate the risk factors for POD development in patients with hyperlipidemia and to construct a clinical prediction model.

MAIN RESULTS

This study included 555 patients. POD incidence was 21.6% in the hyperlipidemia group and 12.7% in the non-hyperlipidemia group. One year following surgery, patients with hyperlipidemia and POD exhibited significantly higher rates of mortality and cognitive decline than did those without POD (p < 0.001). A multifactorial logistic clinical prediction model was constructed from seven independent risk factors for POD development in patients with hyperlipidemia, including education, preoperative total cholesterol (TC), preoperative triglyceride (TG), diet, history of hypertension, Sedation-Agitation Scale, and postoperative trimethylamine N-oxide expression level, and it had the highest predictive value for POD development in patients with hyperlipidemia.

CONCLUSIONS

Compared with those without hyperlipidemia, patients with hyperlipidemia had higher POD incidence. Elevated serum TC and TG levels are independent risk factors for POD in patients with hyperlipidemia. The study's findings could help develop strategies for improving POD and hyperlipidemia treatment.

Transcutaneous carbon dioxide monitoring in children undergoing rigid bronchoscopy: a prospective blinded observational study

PURPOSE

Anesthetic management during rigid bronchoscopy in children can be challenging, and continuous end-tidal carbon dioxide (EtCO2) monitoring is often unachievable. Transcutaneous carbon dioxide (TcCO2) monitoring is strongly correlated with the partial pressure of carbon dioxide (PaCO2) and EtCO2. We aimed to investigate the incidence of hypercapnia in children undergoing rigid bronchoscopy.

METHODS

We enrolled patients aged < 18 yr scheduled for rigid bronchoscopy in a prospective observational study. We recorded TcCO2 values from anesthesia induction to the postanesthesia care unit (PACU) stay. We ended monitoring when TcCO2 reached values ≤ 50 mm Hg. The operating room (OR) team was blinded to the TcCO2. The outcome of primary interest was the incidence of hypercapnia (TcCO2 > 50 mm Hg) in the OR. Other outcomes were the incidences of hypercapnia in the PACU and severe hypercapnia (TcCO2 > 90 mm Hg), factors possibly related to hypercapnia (patient, surgery, or anesthesia factors), and the incidence of perioperative adverse events.

RESULTS

A total of 30 patients were enrolled. The median [interquartile range (IQR)] age was 3.5 [1.5-8.0] yr. The incidence of hypercapnia was 100% in the OR and 60% in the PACU. Five cases (17%) presented with severe hypercapnia in the OR. The highest median [IQR] TcCO2 was 69 [61-79] mm Hg. The most common adverse event was oxygen desaturation (57%, 17/30). Patients with severe hypercapnia had long stays in the PACU.

CONCLUSION

Hypercapnia was a frequent event in children undergoing rigid bronchoscopy and severe hypercapnia was associated with a long PACU stay. Further studies are needed to assess the utility of TcCO2 monitoring in guiding ventilatory interventions during these cases.

Delayed Emergence From Anesthesia Due to Posterior Reversible Encephalopathy Syndrome (PRES): A Case Report

Posterior reversible encephalopathy syndrome (PRES) is a rare clinical and radiological syndrome that presents as rapid onset of neurological symptoms such as headache, visual loss, impaired mental status, and seizure activity associated with characteristic focal white matter vasogenic edema. When promptly recognized and managed, these changes are usually reversible. PRES is most commonly associated with hypertensive crises, renal insufficiency, and the use of immunosuppressive therapies, though it may arise in various clinical contexts. Despite its significance, reports of PRES in the field of anesthesiology remain limited. This case report presents the case of a 46-year-old male admitted for elective ambulatory ophthalmic surgery under general anesthesia who developed delayed emergence from anesthesia and post-operative blindness, both attributed to the intraoperative onset of PRES. Anesthesiologists should be vigilant for PRES as a potential complication during the perioperative period, and consider it in the differential diagnosis for delayed emergence from anesthesia. Clinical suspicion should warrant prompt imagiological confirmation by magnetic resonance imaging (MRI), as delayed recognition and management can result in severe and long-term neurological disability.

Analysis of Adverse Events in the Postanesthesia Unit at a Tertiary Pediatric Hospital

PURPOSE

The postanesthesia care unit (PACU) is an indispensable part of modern medicine which provides critical care to patients to ensure safe and smooth emergence from anesthesia. The adverse events in the PACU have been widely investigated in adults. However, little is known about the adverse events in pediatric populations. This study was designed to investigate adverse events, including the incidence, disease spectrum, and possible risk factors, in pediatric patients in the PACU at a tertiary pediatric hospital.

DESIGN

This is a retrospective observational study.

METHODS

Children admitted to the PACU at the Children's Hospital of Fudan University from September 2021 to August 2022 were included in the study. The following adverse events were recorded: hypothermia, fever, adverse airway events, hypotension, hypertension, prolonged length of stay in PACU, pain, reintubation, neurological events, unplanned admission to the intensive care unit, arrhythmia, water-electrolyte imbalance, and bleeding requiring medical intervention. Descriptive analyses, t tests, and χ2 tests were performed.

FINDINGS

A total of 16,012 children were included in the study, and 305 adverse events occurred in 237 (1.48%) children. The three most frequently occurring adverse events were prolonged stay in the PACU (8.4%), adverse airway events (5.6%), and abnormal temperature (2.7%). Age, American Society of Anesthesiologists' grade, and general surgery were independent risk factors of both overall adverse events and prolonged stay in the PACU in multivariate logistic regression analysis. Children with adverse events stayed in the PACU significantly longer than those without adverse events (60.04 ± 1.01 vs 95.8 ± 47.25 minutes, P < .05). Compared with the other surgeries, a significantly higher proportion of severe pain (37.5% vs 0%) after thoracic surgery, prolonged stay in the PACU (52.9% vs 36.4%) after general surgery, and neurological events (14.7% vs 0%) after neurological surgery was detected, while a significantly lower proportion of adverse airway events after general surgery (21.1% vs 43%) and neurological surgery (8.8% vs 43%) was detected, respectively.

CONCLUSIONS

Our study reports the current incidence and spectrum of adverse events in the PACU at a tertiary pediatric hospital. Patients with young age, high American Society of Anesthesiologists' grade, and those from the general surgery department are at a significantly increased risk of adverse events in the PACU. Significant differences were detected in the proportion of specific adverse events after specific surgeries.

Cardiopulmonary adaptations of a diving marine mammal, the bottlenose dolphin: Physiology during anesthesia

Diving marine mammals are a diverse group of semi- to completely aquatic species. Some species are targets of conservation and rehabilitation efforts; other populations are permanently housed under human care and may contribute to clinical and biomedical investigations. Veterinary medical care for species under human care, at times, may necessitate the use of general anesthesia for diagnostic and surgical indications. However, the unique physiologic and anatomic adaptations of one representative diving marine mammal, the bottlenose dolphin, present several challenges in providing ventilatory and cardiovascular support to maintain adequate organ perfusion under general anesthesia. The goal of this review is to highlight the unique cardiopulmonary adaptations of the completely aquatic bottlenose dolphin (Tursiops truncatus), and to identify knowledge gaps in our understanding of how those adaptations influence their physiology and pose potential challenges for sedation and anesthesia of these mammals.

SQI-DOANet: electroencephalogram-based deep neural network for estimating signal quality index and depth of anaesthesia

Objective. Monitoring the depth of anaesthesia (DOA) during surgery is of critical importance. However, during surgery electroencephalography (EEG) is usually subject to various disturbances that affect the accuracy of DOA. Therefore, accurately estimating noise in EEG and reliably assessing DOA remains an important challenge. In this paper, we proposed a signal quality index (SQI) network (SQINet) for assessing the EEG signal quality and a DOA network (DOANet) for analyzing EEG signals to precisely estimate DOA. The two networks are termed SQI-DOANet.Approach. The SQINet contained a shallow convolutional neural network to quickly determine the quality of the EEG signal. The DOANet comprised a feature extraction module for extracting features, a dual attention module for fusing multi-channel and multi-scale information, and a gated multilayer perceptron module for extracting temporal information. The performance of the SQI-DOANet model was validated by training and testing the model on the large VitalDB database, with the bispectral index (BIS) as the reference standard.Main results. The proposed DOANet yielded a Pearson correlation coefficient with the BIS score of 0.88 in the five-fold cross-validation, with a mean absolute error (MAE) of 4.81. The mean Pearson correlation coefficient of SQI-DOANet with the BIS score in the five-fold cross-validation was 0.82, with an MAE of 5.66.Significance. The SQI-DOANet model outperformed three compared methods. The proposed SQI-DOANet may be used as a new deep learning method for DOA estimation. The code of the SQI-DOANet will be made available publicly athttps://github.com/YuRui8879/SQI-DOANet.

Antagonism of propofol anesthesia by alkyl-fluorobenzene derivatives

Despite their frequent use across many clinical settings, general anesthetics are medications with lethal side effects and no reversal agents. A fluorinated analogue of propofol has previously been shown to antagonize propofol anesthesia in tadpoles and zebrafish, but little further investigation of this class of molecules as anesthetic antagonists has been conducted. A 13-member library of alkyl-fluorobenzene derivatives was tested in an established behavioral model of anesthesia in zebrafish at 5 days post fertilization. These compounds were examined for their ability to antagonize propofol and two volatile anesthetics, as well as their interaction with the anesthetic-binding model protein apoferritin. Two compounds provided significant antagonism of propofol, and when combined, were synergistic, suggesting more than one antagonist sensitive target site. These compounds did not antagonize the volatile anesthetics, indicating some selectivity amongst general anesthetics. For the compounds with the most antagonistic potency, similarities in structure and binding to apoferritin may be suggestive of competitive antagonism; however, this was not supported by a Schild analysis. This is consistent with multiple targets contributing to general anesthesia, but whether these are physiologic antagonists or are antagonists at only some subset of the many anesthetic potential targets remains unclear, and will require additional investigation.

Predictive Factors for Delayed Recovery From Anesthesia in Patients Receiving Free Vascularized Flap Reconstruction for Head and Neck Defects: A Retrospective Cohort Study

OBJECTIVE

Free flap reconstruction for head and neck defects is currently a common procedure. This study aimed to create and validate a predictive model for identifying patients at risk of delayed recovery from anesthesia after free flap reconstruction for head and neck defect.

METHODS

Electronic medical records from all patients were retrospectively collected. The primary outcome variable was delayed recovery from anesthesia. The least absolute shrinkage and selection operator regression model was employed to identify the most relevant features, followed by the construction of a nomogram model using multivariable logistic regression analysis. The discriminatory power, calibration, and clinical utility of the nomogram model were assessed using receiver operating characteristic curve analysis, calibration curve analysis, and decision curve analysis, respectively.

RESULTS

This novel nomogram model incorporated 4 predictors for delayed recovery from anesthesia: preoperative albumin, intraoperative fresh frozen plasma infusion, preoperative platelet-to-lymphocyte ratio, and duration of intraoperative hypotension. The area under the receiver operating characteristic curve (area under the curve) for the nomogram model was determined to be 0.821 (95% CI: 0.803-0.836). After internal validation, the corrected area under the curve was found to be 0.768 (95% CI: 0.639-0.812). In addition, the model exhibited well-fitted calibration curves and demonstrated favorable clinical usability as indicated by the calibration curve and decision curve analysis curve.

CONCLUSION

The authors created and validated a novel predictive model utilizing a limited number of 4 predictors, yet exhibiting commendable predictive performance. This innovative tool holds the potential to mitigate delayed recovery from anesthesia and enhance the efficient allocation of medical resources.

Inhalational Agent Dosing Behaviors of Anesthesia Practitioners Cause Variability in End-Tidal Concentrations at the End of Surgery and Prolonged Times to Tracheal Extubation

INTRODUCTION

Prolonged times to tracheal extubation are intervals from the end of surgery to extubation ≥15 minutes. We examined why there are associations with the end-tidal inhalational agent concentration as a proportion of the age‑adjusted minimum alveolar concentration (MAC fraction) at the end of surgery.

METHODS

The retrospective cohort study used 11.7 years of data from one hospital. All p‑values were adjusted for multiple comparisons.

RESULTS

There was a greater odds of prolonged time to extubation if the anesthesia practitioner was a trainee (odds ratio 1.68) or had finished fewer than five cases with the surgeon during the preceding three years (odds ratio 1.12) (both P<0.0001). There was a greater risk of prolonged time to extubation if the MAC fraction was >0.4 at the end of surgery (odds ratio 2.66, P<0.0001). Anesthesia practitioners who were trainees and all practitioners who had finished fewer than five cases with the surgeon had greater mean MAC fractions at the end of surgery and had greater relative risks of the MAC fraction >0.4 at the end of surgery (all P<0.0001). The source for greater MAC fractions at the end of surgery was not greater MAC fractions throughout the anesthetic because the means during the case did not differ among groups. Rather, there was substantial variability of MAC fractions at the end of surgery among cases of the same anesthesia practitioner, with the mean (standard deviation) among practitioners of each practitioner's standard deviation being 0.35 (0.05) and the coefficient of variation being 71% (13%).

CONCLUSION

More prolonged extubations were associated with greater MAC fractions at the end of surgery. The cause of the large MAC fractions was the substantial variability of MAC fractions among cases of each practitioner at the end of surgery. That variability matches what was expected from earlier studies, both from variability among practitioners in their goals for the MAC fraction given at the start of surgical closure and from inadequate dynamic forecasting of the timing of when surgery would end. Future studies should examine how best to reduce prolonged extubations by using anesthesia machines' display of MAC fraction and feedback control of end-tidal agent concentration.

Emergence Electroencephalography in an Unresponsiveness Geriatric Patient in the Postanesthesia Care Unit: A Case Report

Incomplete neurological awakening manifested as aberrant patterns of electroencephalography (EEG) at emergence may be responsible for an unresponsive patient in the postanesthesia care unit (PACU). We describe a case of an individual who remained unresponsive but awake in the PACU. Retrospective, intraoperative EEG analysis showed low alpha power and a sudden shift from deep delta to arousal preextubation. We explored parallels with diminished motivation disorders and anesthesia-induced sleep paralysis due to imbalances in anesthetic drug sensitivity between brain regions. Our findings highlight the relevance of end-anesthesia EEG patterns in diagnosing delayed awakening.

Orexin receptor 2 agonist activates diaphragm and genioglossus muscle through stimulating inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons in rodents

Orexin-mediated stimulation of orexin receptors 1/2 (OX[1/2]R) may stimulate the diaphragm and genioglossus muscle via activation of inspiratory neurons in the pre-Bötzinger complex, which are critical for the generation of inspiratory rhythm, and phrenic and hypoglossal motoneurons. Herein, we assessed the effects of OX2R-selective agonists TAK-925 (danavorexton) and OX-201 on respiratory function. In in vitro electrophysiologic analyses using rat medullary slices, danavorexton and OX-201 showed tendency and significant effect, respectively, in increasing the frequency of inspiratory synaptic currents of inspiratory neurons in the pre-Bötzinger complex. In rat medullary slices, both danavorexton and OX-201 significantly increased the frequency of inspiratory synaptic currents of hypoglossal motoneurons. Danavorexton and OX-201 also showed significant effect and tendency, respectively, in increasing the frequency of burst activity recorded from the cervical (C3-C5) ventral root, which contains axons of phrenic motoneurons, in in vitro electrophysiologic analyses from rat isolated brainstem-spinal cord preparations. Electromyogram recordings revealed that intravenous administration of OX-201 increased burst frequency of the diaphragm and burst amplitude of the genioglossus muscle in isoflurane- and urethane-anesthetized rats, respectively. In whole-body plethysmography analyses, oral administration of OX-201 increased respiratory activity in free-moving mice. Overall, these results suggest that OX2R-selective agonists enhance respiratory function via activation of the diaphragm and genioglossus muscle through stimulation of inspiratory neurons in the pre-Bötzinger complex, and phrenic and hypoglossal motoneurons. OX2R-selective agonists could be promising drugs for various conditions with respiratory dysfunction.

Electrical stimulation of the ventral tegmental area restores consciousness from sevoflurane-, dexmedetomidine-, and fentanyl-induced unconsciousness in rats

BACKGROUND

Dopaminergic neurons in the ventral tegmental area (VTA) are crucially involved in regulating arousal, making them a potential target for reversing general anesthesia. Electrical deep brain stimulation (DBS) of the VTA restores consciousness in animals anesthetized with drugs that primarily enhance GABAA receptors. However, it is unknown if VTA DBS restores consciousness in animals anesthetized with drugs that target other receptors.

OBJECTIVE

To evaluate the efficacy of VTA DBS in restoring consciousness after exposure to four anesthetics with distinct receptor targets.

METHODS

Sixteen adult Sprague-Dawley rats (8 female, 8 male) with bipolar electrodes implanted in the VTA were exposed to dexmedetomidine, fentanyl, ketamine, or sevoflurane to produce loss of righting, a proxy for unconsciousness. After receiving the dopamine D1 receptor antagonist, SCH-23390, or saline (vehicle), DBS was initiated at 30 μA and increased by 10 μA until reaching a maximum of 100 μA. The current that evoked behavioral arousal and restored righting was recorded for each anesthetic and compared across drug (saline/SCH-23390) condition. Electroencephalogram, heart rate and pulse oximetry were recorded continuously.

RESULTS

VTA DBS restored righting after sevoflurane, dexmedetomidine, and fentanyl-induced unconsciousness, but not ketamine-induced unconsciousness. D1 receptor antagonism diminished the efficacy of VTA stimulation following sevoflurane and fentanyl, but not dexmedetomidine.

CONCLUSIONS

Electrical DBS of the VTA restores consciousness in animals anesthetized with mechanistically distinct drugs, excluding ketamine. The involvement of the D1 receptor in mediating this effect is anesthetic-specific.

Pushing the Limits of Minimally Invasive Spine Surgery-From Preoperative to Intraoperative to Postoperative Management

The introduction of minimally invasive surgery ushered in a new era of spine surgery by minimizing the undue iatrogenic injury, recovery time, and blood loss, among other complications, of traditional open procedures. Over time, technological advancements have further refined the care of the operative minimally invasive spine patient. Moreover, pre-, and postoperative care have also undergone significant change by way of artificial intelligence risk stratification, advanced imaging for surgical planning and patient selection, postoperative recovery pathways, and digital health solutions. Despite these advancements, challenges persist necessitating ongoing research and collaboration to further optimize patient care in minimally invasive spine surgery.

Danavorexton (TAK-925): an orexin receptor 2 agonist as a new 'arousal' agent

A preclinical study in animals has further characterised a new 'arousal' agent. Danavorexton (TAK-925) is an agonist for orexin receptor 2 where it promotes recovery from inhalational and i.v. anaesthesia and opioid sedation. Although danavorexton reverses opioid sedation, it does not compromise analgesia. This could be a useful addition to the postoperative drug cupboard.

Time to Wake Up! The Ongoing Search for General Anesthetic Reversal Agents

How general anesthetics work remains a topic of ongoing study. A parallel field of research has sought to identify methods to reverse general anesthesia. Reversal agents could shorten patients' recovery time and potentially reduce the risk of postoperative complications. An incomplete understanding of the mechanisms of general anesthesia has hampered the pursuit for reversal agents. Nevertheless, the search for reversal agents has furthered understanding of the mechanisms underlying general anesthesia. The study of potential reversal agents has highlighted the importance of rigorous criteria to assess recovery from general anesthesia in animal models, and has helped identify key arousal systems (e.g., cholinergic, dopaminergic, and orexinergic systems) relevant to emergence from general anesthesia. Furthermore, the effects of reversal agents have been found to be inconsistent across different general anesthetics, revealing differences in mechanisms among these drugs. The presynapse and glia probably also contribute to general anesthesia recovery alongside postsynaptic receptors. The next stage in the search for reversal agents will have to consider alternate mechanisms encompassing the tripartite synapse.

Effects of the orexin receptor 2 agonist danavorexton on emergence from general anaesthesia and opioid-induced sedation, respiratory depression, and analgesia in rats and monkeys

BACKGROUND

Delayed emergence from general anaesthesia, opioid-induced sedation, and opioid-induced respiratory depression is associated with perioperative complications. We characterised the preclinical effects of the orexin receptor 2 (OX2R)-selective agonist danavorexton (TAK-925) on emergence from anaesthesia and reversal of fentanyl-induced sedation, respiratory depression, and analgesia.

METHODS

Emergence from isoflurane- or propofol-induced anaesthesia and fentanyl-induced sedation were investigated by righting reflex, rotarod, and electroencephalography in rats or monkeys. Fentanyl-induced respiratory depression was assessed by arterial blood gas analysis and whole-body plethysmography in rats and monkeys. Analgesia was evaluated using formalin- and skin incision-induced pain models in rats.

RESULTS

Danavorexton shortened emergence from isoflurane- or propofol-induced anaesthesia and from fentanyl-induced sedation at 1 (P=0.005), 3 (P=0.006), and 3 mg kg-1 s.c. (P=0.022), respectively, by righting reflex in rats. Danavorexton (10 mg kg-1 s.c.) accelerated recovery from isoflurane-, propofol- and fentanyl-induced motor impairment in separate rotarod tests in rats (P=0.008, P=0.007, P=0.017, respectively), and reversed anaesthesia and fentanyl-induced delta-power increases. Danavorexton shortened emergence (return of righting reflex) from isoflurane- or propofol-induced anaesthesia at 1 (P=0.002) and 3 mg kg-1 (P=0.004), respectively, in cynomolgus monkeys. Danavorexton (10 mg kg-1 s.c.) reversed fentanyl-induced increase in Pco2 (P=0.006), and decrease in Po2 (P=0.015) and pH (P<0.001) in rats, and at 3 mg kg-1 s.c. reversed fentanyl-induced increase in Pco2 (P=0.007), and decrease in Po2 (P=0.013) and SO2 (P=0.036) in monkeys. Danavorexton increased minute volume and tidal volume in fentanyl-treated animals. Danavorexton at ≤10 mg kg-1 s.c. did not compromise fentanyl analgesia in rat formalin- and skin incision-induced pain models.

CONCLUSIONS

Danavorexton promoted recovery from anaesthesia and fentanyl-induced sedation, and antagonised fentanyl-induced respiratory depression without compromising fentanyl analgesia.

Comparisons of fentanyl and sufentanil on recovery time after inguinal hernia repair in children: a randomized clinical trial

BACKGROUND

Inguinal hernia repair is a common pediatric procedure. We studied postoperative recovery times in children undergoing laparoscopic inguinal hernia repair with anesthesia induced by fentanyl versus sufentanil.

METHODS

We performed a pilot randomized clinical trial between February and December 2022. Eligible children were assigned into two age groups, 2-6 and 6-12 years old groups. Then, children in each age group were randomly assigned into either the fentanyl (2 µg/kg) or sufentanil (0.2 µg/kg) group for anesthesia induction. Baseline characteristics were collected. The primary outcome was the postoperative recovery time, which was recorded as the time period from extubation to a Steward recovery score reaching 6. Secondary outcomes included surgical duration, anesthetic duration, intubation duration, and intraoperative hemorrhage.

RESULTS

There were 300 children, with 75 children in each group. In the 2-6 years old group, children who received fentanyl had statistically significantly shorter postoperative recovery times than children who received sufentanil (0.9 ± 0.4 versus 1.5 ± 0.3 h, P < 0.001). However, in the 6-12 years old group, children who received fentanyl had statistically significantly longer postoperative recovery times than children who received sufentanil (1.2 ± 0.4 versus 0.8 ± 0.4 h, P < 0.001). Baseline characteristics and secondary outcomes were comparable between two groups.

CONCLUSIONS

Anesthesia induction with fentanyl or sufentanil resulted in different postoperative recovery times after laparoscopic inguinal hernia repair in children in different age groups. More studies are required to determine the appropriate induction anesthetic in children of different ages.

TRIAL REGISTRATION

The study protocol was retrospectively registered online at the Chinese Clinical Trial Registry (registration number ChiCTR2300072177, retrospectively registered on 06/06/2023).

Comparing Perioperative Outcomes of Total Intravenous Anesthesia (TIVA) With Volatile Anesthesia in Patients With Obesity: A Systematic Review

In this systematic review, the perioperative outcomes of total intravenous anesthesia (TIVA) and volatile anesthesia were compared in obese adults (BMI ≥ 30 kg/m²) undergoing elective surgery. The review analyzed data from 12 randomized-controlled trials involving 935 patients, sourced from PubMed/MEDLINE (Medical Literature Analysis and Retrieval System Online), Cochrane, Scopus, and Web of Science databases. The focus was on intraoperative vital signs, emergence time, postoperative nausea and vomiting (PONV), duration of post-anesthesia care unit (PACU) stay, and ICU admission rates. Findings showed that TIVA (using propofol) might reduce PONV, but there were no significant differences in other outcomes compared to volatile anesthesia (with desflurane as the most common agent). The review highlights the need for more research, especially comparing sevoflurane with TIVA, to establish clear clinical guidelines for anesthesia in obese patients.

Antagonism of Propofol Anesthesia by Alkyl-fluorobenzene Derivatives

Despite their frequent use across many clinical settings, general anesthetics are medications with lethal side effects and no reversal agents. A fluorinated analogue of propofol has previously been shown to antagonize propofol anesthesia in tadpoles and zebrafish, but little further investigation of this class of molecules as anesthetic antagonists has been conducted. A 13-member library of alkyl-fluorobenzene derivatives was tested in an established behavioral model of anesthesia in zebrafish at 5 days post fertilization. These compounds were examined for their ability to antagonize propofol and two volatile anesthetics, as well as their binding to the anesthetic-binding model protein apoferritin. The two compounds demonstrating highest antagonistic potency were found to bind apoferritin in a manner similar to propofol. Selected compounds did not show antagonism of volatile anesthetics, indicating some selectivity of this antagonism. Similarities in structure and binding to apoferritin as well as a Schild analysis are suggestive of competitive antagonism, but like the anesthetics, the potential mechanism(s) of these antagonists will require further mechanistic investigation.

Machines, mathematics, and modules: the potential to provide real-time metrics for pain under anesthesia

The brain-based assessments under anesthesia have provided the ability to evaluate pain/nociception during surgery and the potential to prevent long-term evolution of chronic pain. Prior studies have shown that the functional near-infrared spectroscopy (fNIRS)-measured changes in cortical regions such as the primary somatosensory and the polar frontal cortices show consistent response to evoked and ongoing pain in awake, sedated, and anesthetized patients. We take this basic approach and integrate it into a potential framework that could provide real-time measures of pain/nociception during the peri-surgical period. This application could have significant implications for providing analgesia during surgery, a practice that currently lacks quantitative evidence to guide patient tailored pain management. Through a simple readout of "pain" or "no pain," the proposed system could diminish or eliminate levels of intraoperative, early post-operative, and potentially, the transition to chronic post-surgical pain. The system, when validated, could also be applied to measures of analgesic efficacy in the clinic.

Neurologic complications after cardiopulmonary bypass - A narrative review

Neurologic complications, associated with cardiac surgery and cardiopulmonary bypass (CPB) in adults, are common and can be devastating in some cases. This comprehensive review will not only consider the broad categories of stroke and neurocognitive dysfunction, but it also summarises other neurological complications associated with CPB, and it provides an update about risks, prevention and treatment. Where appropriate, we consider the impact of off-pump techniques upon our understanding of the contribution of CPB to adverse outcomes.

A retrospective comparative study of anesthesia with remimazolam and remifentanil versus dexmedetomidine and remifentanil for transcatheter aortic valve replacement

Remimazolam, an ultrashort-acting benzodiazepine, allows for rapid and reliable arousal. Rapid awakening using remimazolam may be beneficial in transcatheter aortic valve replacement (TAVR), as it allows rapid detection of neurologic deficits. The purpose of this study was to compare arousal time and outcomes between monitored anesthesia care (MAC) with remimazolam and remifentanil and conventional MAC with dexmedetomidine, propofol, and remifentanil. This study was a single center retrospective study. All TAVR cases performed under MAC (MAC-TAVR) at our institution between 2019 and 2021 were included. Patients were classified by anesthesia method into remimazolam and dexmedetomidine groups. Among 258 MAC-TAVR patients, 253 were enrolled. After propensity score matching, 76 patients were assigned to each group. The time from end of drug-administration to arousal [20.0 (16.0, 24.0) min vs. 38.5 (30.0, 56.3) min, p < 0.0001] and the time from attempted-arousal to arousal [1.0 (1.0, 1.0) min vs. 12.5 (3.0, 26.8) min, p < 0.0001] were significantly shorter in the remimazolam group. There was no significant difference in the length of ICU stay [2.0 (2.0, 2.0) days vs. 2.0 (2.0, 2.0) days, p = 0.157] and postoperative hospital stay [6.0 (4.0, 9.0) days vs. 5.0 (4.0, 8.0) days, p = 0.262].Trial registration: Clinical trial number: R03-123, Registry URL: https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000051635 Registration number: UMIN000045195, Principal investigator's name: Atsuhiro Kitaura, Date of registration: 20 August 2021.

Intraoperative body temperature and emergence delirium in elderly patients after non-cardiac surgery: A secondary analysis of a prospective observational study

BACKGROUND

Emergence delirium (ED) is a kind of delirium that occured in the immediate post-anesthesia period. Lower body temperature on post-anesthesia care unit (PACU) admission was an independent risk factor of ED. The present study was designed to investigate the association between intraoperative body temperature and ED in elderly patients undergoing non-cardiac surgery.

METHODS

This study was a secondary analysis of a prospective observational study. Taking baseline body temperature as a reference, intraoperative absolute and relative temperature changes were calculated. The relative change was defined as the amplitude between intraoperative lowest/highest temperature and baseline reference. ED was assessed with the confusion assessment method for intensive care unit at 10 and 30 min after PACU admission and before PACU discharge.

RESULTS

A total of 874 patients were analyzed with a mean age of 71.8 ± 5.3 years. The incidence of ED was 38.4% (336/874). When taking 36.0°C, 35.5°C, and 35.0°C as thresholds, the incidences of absolute hypothermia were 76.7% (670/874), 38.4% (336/874), and 17.5% (153/874), respectively. In multivariable logistic regression analysis, absolute hypothermia (lowest value <35.5°C) and its cumulative duration were respectively associated with an increased risk of ED after adjusting for confounders including age, education, preoperative mild cognitive impairment, American Society of Anesthesiologists grade, duration of surgery, site of surgery, and pain intensity. Relative hypothermia (decrement >1.0°C from baseline) and its cumulative duration were also associated with an increased risk of ED, respectively. When taking the relative increment >0.5°C as a threshold, the incidence of relative hyperthermia was 21.7% (190/874) and it was associated with a decreased risk of ED after adjusting above confounders.

CONCLUSIONS

In the present study, we found that intraoperative hypothermia, defined as either absolute or relative hypothermia, was associated with an increased risk of ED in elderly patients after non-cardiac surgery. Relative hyperthermia, but not absolute hyperthermia, was associated with a decreased risk of ED.

REGISTRATION

Chinese Clinical Trial Registry (No. ChiCTR-OOC-17012734).

Modulating anesthetic emergence with pathway-selective dopamine signaling

PURPOSE OF REVIEW

To summarize the recent preclinical findings investigating dopaminergic circuits for their involvement in reversing anesthetic-induced unconsciousness.

RECENT FINDINGS

The release of dopamine from the ventral tegmental area onto dopamine D1 receptor-expressing neurons in the nucleus accumbens promotes emergence following general anesthesia. Two relevant targets of dopamine D1 receptor-expressing neurons in the nucleus accumbens include the lateral hypothalamus and ventral pallidum. Activating mesocortical dopaminergic projections from the ventral tegmental area to the prelimbic cortex has also been shown to hasten emergence from general anesthesia. In contrast, the nigrostriatal dopamine pathway is not involved in regulating anesthetic emergence. The role of the tuberoinfundibular endocrine dopamine pathway remains to be tested; however, recent studies have identified an important function of neuroendocrine signaling on modulating general anesthesia.

SUMMARY

Potential avenues for accelerating anesthetic emergence may be found through targeting specific arousal-promoting pathways in the brain. Accumulating evidence from rodent studies manipulating cell type- and circuit-specific signaling pathways have identified dopamine as a potent modulator of general anesthesia. Specifically, dopamine signaling along the mesolimbic and mesocortical pathways plays a fundamental role in regulating consciousness.

Delayed awakening and its associated factor following general anesthesia service, 2022: a cross-sectional study

Background

The time to emerge from anesthesia is affected by patient factors, anesthetic factors, the duration of surgery, and preoperative and intraoperative pain management.

Objective

This study aimed to determine the prevalence and contributing factors of delayed awakening following general anesthesia.

Method

A cross-sectional study was conducted from January to June 2022. After getting ethical approval with the permission number S/C/R 37/01/2022, willing patients participate with written informed consent. Chart reviews in the preoperative and postoperative recovery rooms were used to collect data. Frequency and percentage with cross-tabulation were used to provide the descriptive statistics. To determine the predictive variables that were associated with the outcome variable, bivariable, and multivariable logistic regression models were fitted. The statistical significance was evaluated using P-values of 0.05 for multivariable regression.

Results

In the current study, a normal emergency occurred in 91.7% of surgical patients receiving general anesthesia, while delayed awakening, emergence with hypoactive, and emergence with delirium occurred in 2.6, 3.9, and 1.8% of cases, respectively. Patients older than 64 years [adjusted odds ratio (AOR): 1.33, 95% CI: 0.83-7.191], being diploma anesthesia providers (AOR: 2.38, 95% CI: 2.05-7.15), opioids (AOR: 2.3, 95% CI: 2.20-5.76), surgery lasting longer than 2 h (AOR: 1.91, 95% CI: 1.83-6.14), estimated blood loss of more than 1500 ml (AOR: 1.20, 95% CI: 0.62-11.30), crystalloid administration of more than 3000 ml (AOR: 3.12, 95% CI: 2.19-7.32), intraoperative hypotension (AOR: 3.37, 95% CI: 2.93-9.41) and extreme body weight, were significantly linked to delayed awakening after general anesthesia.

Conclusion

Although delayed emergence is an uncommon condition with a number of contributing causes, it is preventable, and once it has occurred, it presents a challenge for anesthetists.

Return of Sound Production as a Biomarker of Bottlenose Dolphin Emergence from Anesthesia

(1) Background: When a human or animal is recovering from general anesthesia, their medical team uses several behavioral and physiological parameters to assess their emergence from the unconscious state to complete wakefulness. However, the return of auditory and acoustic behaviors indicative of the complete return of consciousness in humans can be difficult to assess in a completely aquatic non-human mammal. Dolphins produce sound using the nasal system while using both passive auditory and active biological sonar (echolocation) to navigate and interrogate their environment. The sounds generated by dolphins, such as whistles and clicks, however, can be difficult to hear when the animal is submerged. (2) Methods: We implemented a system to audibly and visually (i.e., using spectrograms) monitor the underwater acoustic behavior of dolphins recovering from anesthesia. (3) Results: Eleven of the twelve recorded dolphins began echolocating within 92 min (Mean = 00:43:41 HH:MM:SS) following spontaneous respirations. In all cases, the dolphins echolocated prior to whistling (Mean = 04:57:47). The return of echolocation was significantly correlated to the return of the righting reflex (Mean = 1:13:44), a commonly used behavioral indicator of dolphin emergence. (4) Conclusions: We suggest that acoustic monitoring for the onset of click production may be a useful supplement to the established medical and behavioral biomarkers of restoring consciousness following anesthesia in bottlenose dolphins.

The effect of aminophylline on the recovery profile after hysterectomy: A randomized controlled double-blinded study

Background and Aims

In anesthesia practice, aminophylline is clinically used to treat bronchospasm. However, due to its antagonistic effect on adenosine, studies have recently focused on the drug's ability to enhance the recovery profile. The aim of this study was to investigate the hypothesis that the administration of aminophylline leads to better recovery after general anesthesia in hysterectomy.

Methods

This randomized controlled double-blinded study, was conducted at Alzahra academic hospital in Guilan, Iran. During December 2022 to March 2023, 70 eligible women scheduled for elective abdominal hysterectomy were divided into two groups. Group A: received 3 mg/kg IV aminophylline diluted in 100 mL of normal saline and Group C: received 100 mL IV normal saline. The time to recovery of consciousness, tracheal extubation and discharge from post anesthesia care unit were recorded. In addition, heart rate, and mean arterial blood pressure were measured at 10 point times including; baseline (T0), immediately before the administration of aminophylline (T1), every 5 min until the end of the surgery(T2,T3,T4,T5,T6), and every 15 min in PACU(T7,T8,T9).

Results

There was no significant difference in terms of demographic data between the study groups. Comparing the two groups, the time of ROC was shorter in Group A than group C; 5.95 ± 1.12 and 8.5 ± 1.77 for Groups A and C, respectively (p < 0.001). The extubation time was shorter in Group A than group C; 7.79 ± 1.48 and 10.55 ± 3.02, for Groups A and C, respectively (p < 0.001). In addition, the discharge time was also shorter in group A than Group C; 30.17 ± 5.24 and 37.57 ± 4.41 for Groups A and C, respectively (p < 0.001). Not serious side effects were reported among 71.4% of cases in Group A and 51.4% in Group C (p = 0.086).

Conclusion

Administration of aminophylline at a dose of 3 mg/kg IV improves the recovery profile after abdominal hysterectomy without serious adverse effects.

Exploring Artificial Intelligence in Anesthesia: A Primer on Ethics, and Clinical Applications

The field of anesthesia has always been at the forefront of innovation and technology, and the integration of Artificial Intelligence (AI) represents the next frontier in anesthesia care. The use of AI and its subtypes, such as machine learning, has the potential to improve efficiency, reduce costs, and ameliorate patient outcomes. AI can assist with decision making, but its primary advantage lies in empowering anesthesiologists to adopt a proactive approach to address clinical issues. The potential uses of AI in anesthesia can be schematically grouped into clinical decision support and pharmacologic and mechanical robotic applications. Tele-anesthesia includes strategies of telemedicine, as well as device networking, for improving logistics in the operating room, and augmented reality approaches for training and assistance. Despite the growing scientific interest, further research and validation are needed to fully understand the benefits and limitations of these applications in clinical practice. Moreover, the ethical implications of AI in anesthesia must also be considered to ensure that patient safety and privacy are not compromised. This paper aims to provide a comprehensive overview of AI in anesthesia, including its current and potential applications, and the ethical considerations that must be considered to ensure the safe and effective use of the technology.

Delayed emergence from anesthesia caused by an intraoperative cerebral embolism of a malignant peripheral nerve sheath tumor in a neurofibromatosis type 1 patient: a case report

BACKGROUND

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas which commonly arise from neurofibromatosis type 1. Lung metastases of the tumors are well-known, but intraoperative cerebral tumor embolisms of MPNSTs have not been reported in literature.

CASE PRESENTATION

A 52-year-old female patient with neurofibromatosis type 1 underwent a right lung partial resection for lung tumors. She was extubated after adequate recovery of spontaneous breathing; however, she could not respond to verbal commands. In the intensive care unit, her neurological examination revealed conjugate eye deviation, right hemiparalysis, and aphasia. Magnetic resonance imaging revealed acute cerebral ischemia, so she underwent an endovascular thrombectomy. The histopathological diagnosis of emboli was a MPNST, which was identical with that of the resected lung tumor.

CONCLUSION

We report the first case of delayed emergence caused by a cerebral tumor embolism of MPNST during partial lung resection.

Effect of high-flow nasal cannula on patients' recovery after inhalation general anesthesia

Objective

To investigate the effect of high-flow nasal cannula (HFNC) and Oxygen Nebuliser mask (ONM) on patients recovering from inhalation anesthesia.

Methods

A retrospective analysis was performed on 128 patients after inhalation of general anesthesia in the recovery room of the Anesthesiology Department of The Fourth Hospital of Hebei Medical University from September 2019 to September 2021. All patients received the same anesthesia induction and analgesia methods, inhalation anesthesia or intravenous-inhalation anesthesia maintenance, recovered spontaneous breathing and removed endotracheal intubation after surgery, then were divided into HFNC group and ONM group for oxygen therapy. HFNC setting mode: flow rate: 20-60 L/minutes, humidification temperature: 37°C, the oxygen concentration was adjusted to maintain finger pulse oxygen saturation SPO2>90%; ONM group, the oxygen flow rate was adjusted to maintain finger pulse oxygen saturation SPO2>90%. All patients in the two groups were compared immediately after they entered the recovery room for 0 minutes,, 10 minutes, and 20 minutes,, including tidal volume, blood gas, Richmond Agitation-Sedation Scale (RASS) score and time from sedation to awakening.

Results

The changes in tidal volume, oxygenation index and RASS score over time in the HFNC group were higher than those in the ONM group (p<0.05), and the awakening time in the HFNC group was faster than that in the ONM group (p<0.01), with significant statistical differences.

Conclusions

Compared with ONM, HFNC can shorten postoperative recovery time, reduce the incidence of agitation and improve lung function and oxygenation state during recovery from anesthesia.

[Central anticholinergic, neuroleptic malignant and serotonin syndromes]

Impaired consciousness is a frequent phenomenon after general anesthesia. In addition to the classical causes (e.g., overhang of sedatives), an impairment of consciousness can also be an adverse side effect of drugs. Many drugs used in anesthesia can trigger these symptoms. Alkaloids, such as atropine can trigger a central anticholinergic syndrome, opioids can promote the occurrence of serotonin syndrome and the administration of a neuroleptic can lead to neuroleptic malignant syndrome. These three syndromes are difficult to diagnose due to the individually very heterogeneous symptoms. Mutual symptoms, such as impaired consciousness, tachycardia, hypertension and fever further complicate the differentiation between the syndromes; however, more individual symptoms, such as sweating, muscle tension or bowl sounds can be helpful in distinguishing these syndromes. The time from the trigger event can also help to differentiate the syndromes. The central anticholinergic syndrome is the fastest to appear, usually taking just a few of hours from trigger to clinical signs, serotonin syndrome takes several hours up to 1 day to show and neuroleptic malignant syndrome usually takes days. The clinical symptoms can range from mild to life-threatening. Generally, mild cases are treated with discontinuation of the trigger and extended observation. More severe cases can require specific antidotes. The specific treatment recommended for central anticholinergic syndrome is physostigmine with an initial dose of 2 mg (0.04 mg/kg body weight, BW) administered over 5 min. For serotonin syndrome an initial dose of 12 mg cyproheptadine followed by 2 mg every 2 h is recommended (maximum 32 mg/day or 0.5 mg/kgBW day-1) but this medication is only available in Germany as an oral formulation. For neuroleptic malignant syndrome 25-120 mg dantrolene (1-2.5 mg/kgBW maximum 10 mg/kgBW day-1) is the recommended treatment.

Development of prediction models to estimate extubation time and midterm recovery time of ophthalmic patients undergoing general anesthesia: a cross-sectional study

BACKGROUND

To develop prediction models for extubation time and midterm recovery time estimation in ophthalmic patients who underwent general anesthesia.

METHODS

Totally 1824 ophthalmic patients who received general anesthesia at Joint Shantou International Eye Center were included. They were divided into a training dataset of 1276 samples, a validation dataset of 274 samples and a check dataset of 274 samples. Up to 85 to 87 related factors were collected for extubation time and midterm recovery time analysis, respectively, including patient factors, anesthetic factors, surgery factors and laboratory examination results. First, multiple linear regression was used for predictor selection. Second, different methods were used to develop predictive models for extubation time and midterm recovery time respectively. Finally, the models' generalization abilities were evaluated using a same check dataset with MSE, RMSE, MAE, MAPE, R-Squared and CCC.

RESULTS

The fuzzy neural network achieved the highest R-Squared of 0.956 for extubation time prediction and 0.885 for midterm recovery time, and the RMSE value was 6.637 and 9.285, respectively.

CONCLUSION

The fuzzy neural network developed in this study had good generalization performance in predicting both extubation time and midterm recovery time of ophthalmic patients undergoing general anesthesia.

TRIAL REGISTRATION

This study is prospectively registered in the Chinese Clinical Trial Registry, registration number: CHiCRT2000036416, registration date: August 23, 2020.

The impact of emergence delirium on hospital length of stay for children who underwent tonsillectomy/adenotonsillectomy: an observational retrospective study

BACKGROUND

Emergence Delirium (ED) is a combination of disturbance of perception and psychomotor agitation that is common in pediatric patients after general anesthesia, especially at preschool age. Since the effect of ED on the length of stay has been studied in adults but infrequently in children, the aim of this study was to investigate the relationship between ED and length of stay in this population.

METHODS

A single center, retrospective, observational study was carried out in children who underwent tonsillectomy or adenotonsillectomy. The Pediatric Anesthesia Emergence Delirium (PAED) scale was used to assess ED. In addition to the time to hospital discharge (time frame 24 hours), drugs used, comorbidities, early postoperative complications, and pain were investigated if potentially associated with the complication.

RESULTS

Four hundred sixteen children aged from 1.5 to 10 years (183 female, 233 male) were included. ED occurred in 25.5% of patients (n = 106). Patients were divided into the ED group and the No-ED group. The discharge time was similar in both groups. No significant differences were observed in the frequency of postoperative complications. The use of fentanyl or dexmedetomidine did not affect ED occurrence. The frequency of pain was greater in the ED group, both in the recovery room and in the ward (p = 0.01).

CONCLUSIONS

The occurrence of ED in children after tonsillectomy/adenotonsillectomy did not extend the length of stay.

Design, synthesis and evaluation of heterocyclic 2-phenylacetate derivatives as water-soluble rapid recovery hypnotics

In this work, a series of novel heterocyclic 2-phenylacetate derivatives were designed and synthesized as water-soluble and rapid recovery hypnotic agents. After introducing heterocyclic ring to the amide group of propanidid, the obtained propanidid derivatives showed greatly improved hydrophilicity and good anesthetic activity. In three animal experiments (mice, rats, and rabbits), compounds 13-15 showed potent hypnotic potency (HD₅₀ = 7.6, 6.5, 7.4 mg/kg in rabbits, respectively) and higher therapeutic indexes (TI = 17.3, 16.6, 15.2 in rabbits, respectively) than propanidid (TI = 14.7 in rabbits) or propofol (TI = 5.4 in rabbits). Moreover, the recovery time of compounds 13-15 (time to walk, 96.6, 79.6, 81.4 s in rabbits, respectively) were shorter than that of propanidid (124.5 s in rabbits) or propofol (425.3 s in rabbits). The experimental results suggested the potential of compounds 13-15 as water-soluble anesthetics with rapid recovery profile.

[Central anticholinergic, neuroleptic malignant and serotonin syndromes : Important differential diagnoses in postoperative impairment of consciousness]

Impaired consciousness is a frequent phenomenon after general anesthesia. In addition to the classical causes (e.g., overhang of sedatives), an impairment of consciousness can also be an adverse side effect of drugs. Many drugs used in anesthesia can trigger these symptoms. Alkaloids, such as atropine can trigger a central anticholinergic syndrome, opioids can promote the occurrence of serotonin syndrome and the administration of a neuroleptic can lead to neuroleptic malignant syndrome. These three syndromes are difficult to diagnose due to the individually very heterogeneous symptoms. Mutual symptoms, such as impaired consciousness, tachycardia, hypertension and fever further complicate the differentiation between the syndromes; however, more individual symptoms, such as sweating, muscle tension or bowl sounds can be helpful in distinguishing these syndromes. The time from the trigger event can also help to differentiate the syndromes. The central anticholinergic syndrome is the fastest to appear, usually taking just a few of hours from trigger to clinical signs, serotonin syndrome takes several hours up to 1 day to show and neuroleptic malignant syndrome usually takes days. The clinical symptoms can range from mild to life-threatening. Generally, mild cases are treated with discontinuation of the trigger and extended observation. More severe cases can require specific antidotes. The specific treatment recommended for central anticholinergic syndrome is physostigmine with an initial dose of 2 mg (0.04 mg/kg body weight, BW) administered over 5 min. For serotonin syndrome an initial dose of 12 mg cyproheptadine followed by 2 mg every 2 h is recommended (maximum 32 mg/day or 0.5 mg/kgBW day^-1) but this medication is only available in Germany as an oral formulation. For neuroleptic malignant syndrome 25-120 mg dantrolene (1-2.5 mg/kgBW maximum 10 mg/kgBW day^-1) is the recommended treatment.

Deconstructing delirium in the post anaesthesia care unit

The course of neuro-cognitive recovery following anaesthesia and surgery is distinctive and poorly understood. Our objective was to identify patterns of neuro-cognitive recovery of the domains routinely assessed for delirium diagnosis in the post anaesthesia care unit (PACU) and to compare them to the cognitive recovery patterns observed in other studies; thereby aiding in the identification of pathological (high risk) patterns of recovery in the PACU. We also compared which of the currently available tests (3D-CAM, CAM-ICU, and NuDESC) is the best to use in PACU. This was a post hoc secondary analysis of data from the Alpha Max study which involved 200 patients aged over 60 years, scheduled for elective surgery under general anaesthesia lasting more than 2 h. These patients were assessed for delirium at 30 min following arrival in the PACU, if they were adequately arousable (Richmond Agitation Sedation Score ≥ −2). All tests for delirium diagnosis (3D-CAM, CAM-ICU, and NuDESC) and the sub-domains assessed were compared to understand temporal recovery of neurocognitive domains. These data were also analysed to determine the best predictor of PACU delirium. We found the incidence of PACU delirium was 35% (3D-CAM). Individual cognitive domains were affected differently. Few individuals had vigilance deficits (6.5%, n = 10 CAM-ICU) or disorganized thinking (19% CAM-ICU, 27.5% 3D-CAM), in contrast attention deficits were common (72%, n = 144) and most of these patients (89.5%, n = 129) were not sedated (RASS ≥ −2). CAM-ICU (27%) and NuDESC (52.8%) detected fewer cases of PACU delirium compared to 3D-CAM. In conclusion, return of neurocognitive function is a stepwise process; Vigilance and Disorganized Thinking are the earliest cognitive functions to return to baseline and lingering deficits in these domains could indicate an abnormal cognitive recovery. Attention deficits are relatively common at 30 min in the PACU even in individuals who appear to be awake. The 3D CAM is a robust test to check for delirium in the PACU.

The effects of ultrasound-guided serratus anterior plane block on intraoperative opioid consumption and hemodynamic stability during breast surgery: A randomized controlled study

AIM

To determine effect of ultrasound-guided serratus anterior plane block (SAPB) on intraoperative opioid consumption in patients undergoing oncoplastic breast surgery under general anesthesia.

METHODS

This study was conducted as a prospective, randomized controlled trial. Forty-four patients enrolled, aged 18 to 75 years with American Society of Anesthesiologists physical status I to III, undergoing elective oncoplastic breast surgery. Patients were randomly allocated to receive SAPB with 20 mL of 0.25% bupivacaine + general anesthesia (group SAPB) or only general anesthesia (group control). The primary outcome was assessing the effect of SAPB on intraoperative remifentanil consumption. Patients were assessed for emergence time, hemodynamic parameters, doses of rescue drugs used to control hemodynamic parameters, and duration of stay in the recovery room.

RESULTS

Preoperative SAPB with 0.25% bupivacaine reduced intraoperative opioid consumption (851.2 ± 423.5 vs 1409.7 ± 756.1 µg, P = .019). Emergence time was significantly shorter in group SAPB (6.19 ± 1.90 minutes) compared to group control (9.50 ± 2.39 minutes; P < .001). There were no significant differences in the doses of rescue drugs used for systolic blood pressure and heart rate between the groups.

CONCLUSIONS

Preoperative SAPB with bupivacaine reduced intraoperative opioid consumption and shortened emergence time and duration of stay in the recovery unit, and hemodynamic stability was maintained without block-related complications.

Electroencephalogram Features of Perioperative Neurocognitive Disorders in Elderly Patients: A Narrative Review of the Clinical Literature

Postoperative neurocognitive disorder (PND) is a common postoperative complication, particularly in older patients. Electroencephalogram (EEG) monitoring, a non-invasive technique with a high spatial-temporal resolution, can accurately characterize the dynamic changes in brain function during the perioperative period. Current clinical studies have confirmed that the power density of alpha oscillation during general anesthesia decreased with age, which was considered to be associated with increased susceptibility to PND in the elderly. However, evidence on whether general anesthesia under EEG guidance results in a lower morbidity of PND is still contradictory. This is one of the reasons that common indicators of the depth of anesthesia were limitedly derived from EEG signals in the frontal lobe. The variation of multi-channel EEG features during the perioperative period has the potential to highlight the occult structural and functional abnormalities of the subcortical-cortical neurocircuit. Therefore, we present a review of the application of multi-channel EEG monitoring to predict the incidence of PND in older patients. The data confirmed that the abnormal variation in EEG power and functional connectivity between distant brain regions was closely related to the incidence and long-term poor outcomes of PND in older adults.

Modeling cortical synaptic effects of anesthesia and their cholinergic reversal

General anesthetics work through a variety of molecular mechanisms while resulting in the common end point of sedation and loss of consciousness. Generally, the administration of common anesthetics induces reduction in synaptic excitation while promoting synaptic inhibition. Exogenous modulation of the anesthetics' synaptic effects can help determine the neuronal pathways involved in anesthesia. For example, both animal and human studies have shown that exogenously induced increases in acetylcholine in the brain can elicit wakeful-like behavior despite the continued presence of the anesthetic. However, the underlying mechanisms of anesthesia reversal at the cellular level have not been investigated. Here we apply a computational model of a network of excitatory and inhibitory neurons to simulate the network-wide effects of anesthesia, due to changes in synaptic inhibition and excitation, and their reversal by cholinergic activation through muscarinic receptors. We use a differential evolution algorithm to fit model parameters to match measures of spiking activity, neuronal connectivity, and network dynamics recorded in the visual cortex of rodents during anesthesia with desflurane in vivo. We find that facilitating muscarinic receptor effects of acetylcholine on top of anesthetic-induced synaptic changes predicts the reversal of anesthetic suppression of neurons' spiking activity, functional connectivity, as well as pairwise and population interactions. Thus, our model predicts a specific neuronal mechanism for the cholinergic reversal of anesthesia consistent with experimental behavioral observations.

Effect of Caffeine on the Acceleration of Emergence from General Anesthesia with Inhalation Anesthetics in Children Undergoing Inguinal Herniorrhaphy: A Randomized Clinical Trial

Background

Awakening following general anesthesia (GA) is one of the most important concerns of anesthesiologists in their daily work. Previous studies on adult humans found that caffeine could accelerate awakening after anesthesia. This study aimed to determine whether or not caffeine can accelerate awakening after anesthesia in children undergoing inguinal herniorrhaphy under GA.

Methods

In this randomized clinical trial, we enrolled 18 children undergoing inguinal herniorrhaphy under GA with inhaled anesthetics from June 2019 to September 2019 in the tertiary hospital affiliated with Shiraz University of Medical Sciences (Shiraz, Iran). These children were randomly allocated to two groups. In group A, the children received intravenous caffeine (10 mg/Kg) at the end of the surgery, and in group B, the children received intravenous normal saline at the end of the surgery. The primary outcome was laryngeal mask airway (LMA) removal time at the end of anesthesia. Intra-operative hemodynamic data and side effects such as nausea, vomiting, dysrhythmia, cyanosis, and seizures in the recovery room were recorded and compared between the two groups. We used the independent-samples t test, Fisher's exact test, and repeated measures ANOVA for analyzing the data. P values<0.05 were considered statistically significant.

Results

There were no significant differences in terms of demographic characteristics and hemodynamic data between the two groups. Furthermore, the time from the induction of anesthesia to laryngeal mask removal was 44.77±7.87 min in the placebo group and 44.55±10.68 min in the caffeine group. Therefore, there was no significant difference between the two groups (P=0.961).

Conclusion

In children undergoing inguinal herniorrhaphy under GA, 10 mg/Kg of caffeine could not accelerate awakening from GA. However, caffeine did not increase the blood pressure and heart rate in the children, and no significant side effects were observed.

Trial Registration Number

IRCT20190511043550N1.

The role of intracerebral dopamine D1 and D2 receptors in sleep-wake cycles and general anesthesia

Dopamine (DA), a monoamine neurotransmitter, is synthesized and released mainly by neurons in the ventral tegmental area and the substantia nigra (SN) pars compacta of the midbrain. DA and its receptors are essential for the regulation of arousal, movement, cognition, reward, and other neurobiological behaviors. Arousal, locomotion, cognition, reward, and other neurobiological functions are all regulated by dopamine and its receptors. Dopamine receptors can be divided into D1-like receptors (including D1 and D5) or D2-like receptors (containing D2, D3, and D4), with D1 and D2 receptors (D1Rs, and D2Rs) being the most important. Currently, studies indicated that D1Rs and D2Rs are tightly involved with the process of sleep-wake and general anesthesia, but the specific mechanism remains unclear. In this review, we compiled the most recent findings, mainly focusing on the structure, distribution, and signal pathway of D1Rs and D2Rs in the central nervous system, as well as the involvement of D1Rs and D2Rs in sleep-wake and general anesthesia. Thus, the investigations of the D1Rs and D2Rs will benefit not only better knowledge for how sleep-wake control works but also the mechanism of general anesthesia.

Electroencephalographic Burst-Suppression, Perioperative Neuroprotection, Postoperative Cognitive Function, and Mortality: A Focused Narrative Review of the Literature

Burst-suppression is an electroencephalographic pattern that results from a diverse array of pathophysiological causes and/or metabolic neuronal suppression secondary to the administration of anesthetic medications. The purpose of this review is to provide an overview of the physiological mechanisms that underlie the burst-suppression pattern and to present in a comprehensive way the available evidence both supporting and in opposition to the clinical use of this electroencephalographic pattern as a therapeutic measure in various perioperative settings.

Identifying c-fos Expression as a Strategy to Investigate the Actions of General Anesthetics on the Central Nervous System

Although general anesthetics have been used in the clinic for more than 170 years, the ways in which they induce amnesia, unconsciousness, analgesia, and immobility remain elusive. Modulations of various neural nuclei and circuits are involved in the actions of general anesthetics. The expression of the immediate-early gene c-fos and its nuclear product, c-fos protein, can be induced by neuronal depolarization; therefore, c-fos staining is commonly used to identify the activated neurons during sleep and/or wakefulness, as well as in various physiological conditions in the central nervous system. Identifying c-fos expression is also a direct and convenient method to explore the effects of general anesthetics on the activity of neural nuclei and circuits. Using c-fos staining, general anesthetics have been found to interact with sleep- and wakefulness-promoting systems throughout the brain, which may explain their ability to induce unconsciousness and emergence from general anesthesia. This review summarizes the actions of general anesthetics on neural nuclei and circuits based on a c-fos expression.

Delayed awakening in neurocritical care

Delayed awakening is defined as a persistent disorder of arousal or consciousness 48 to 72h after sedation interruption in critically ill patients. Delayed awakening is either a component of coma or delirium. It results in longer hospital stays and increased mortality. It is therefore a diagnostic, therapeutic and prognostic emergency. In severe brain injured patients, delayed awakening may be related to the primary neurological injury or to secondary systemic insults related to organ failure associated with intensive care. In the present review, we propose diagnostic, therapeutic and prognostic algorithms for managing delayed awaking in neuro-ICU brain injured patients.