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

Cortical signatures linked to behavior quantitatively track arousal levels

While current arousal level assessments in patients with disorders of consciousness discriminate altered states of consciousness, there are significant limitations in characterizing the transition from one state to another or quantifying the frequent arousal level fluctuations observed in a patient. Here, we identified a repeated, temporally discrete, dynamical pattern evident in the recovery of consciousness from anesthesia and brain injury coma models in rodents. We prospectively validated these features we label "Arousal Units" (AU) in neonatal humans recovering from static hypoxic injuries and senior patients emerging from anesthesia indicating their generalizability. The AUs lawfully link changes in spectral power and breathing frequency and reliably associate with motor changes. Distinctive cortical patterns within AUs can be transformed into arousal indices, determining arousal levels. The reliability of these events is demonstrated across intact and brain-injured states and translates to the human brain; extracting these stereotyped dynamics could aid anesthesia monitoring, tracking coma recovery, and identifying cognitive motor dissociation.

Changes in cortical delta power during chronic invasive epilepsy monitoring

OBJECTIVE

Cortical delta band (1-4 Hz) activity is considered a biomarker for states of altered consciousness, with increased delta power observed during anesthesia, sleep, coma, and delirium. The current study sought to characterize delta power following electrode implantation with respect to patient demographics and clinical characteristics as well as type and duration of surgery.

METHODS

Participants were 25 adult neurosurgical patients implanted with intracranial electrodes for clinical monitoring of their epilepsy. Resting state cortical activity was recorded at multiple occasions over the course of the monitoring period. The initial time point was defined as the first recording within 72 h following surgery. Analyses of cortical activity were conducted using a linear mixed effects modeling approach to account for within-participant correlations and between-participant heterogeneity.

RESULTS

Throughout the monitoring period, delta power decreased in frontal, occipital, parietal, and temporal regions, indicating a global phenomenon. By contrast, beta (14-30 Hz) power remained stable. Delta power was higher following surgical cases that required craniotomy compared to stereoelectroencephalography cases. Surgery duration and anesthesia emergence duration were associated with higher delta power. Recordings from depth electrodes showed higher delta power compared to subdural electrodes. No significant effects of patients' age, sex, white blood cell count, antiseizure medication, and opioid medication dosage on postoperative delta power were found.

SIGNIFICANCE

The results are consistent with a postoperative elevation in delta power that resolves over the course of the monitoring period and indicate an association between increased delta power and craniotomy surgery, as well as longer surgery and emergence durations. The current work provides a comprehensive analysis of surgical, clinical, and physiological factors, suggests risk factors, and lays fundamental groundwork for future studies.

A probabilistic model of behavioural emergence from general anaesthesia in mice

BACKGROUND

Time to emergence from general anaesthesia is highly variable between individuals. This variability has been attributed to individual differences in anaesthetic sensitivity. However, this hypothesis has not been verified experimentally. We explicitly test this hypothesis by quantifying emergence from anaesthesia repeatedly in the same individuals over time.

METHODS

Genetically identical adult (12-24 weeks old) male (n=40) and female (n=20) C57BL/6J mice were exposed to 2 h of isoflurane (0.90 vol%) on 10 separate occasions. Time to emergence was measured using the return of the righting reflex. Predictions of the standard effect-site pharmacokinetic-pharmacodynamic (PK-PD) model and neuronal dynamics model of stochastic fluctuations between the awake and anaesthetised states were fit to observed emergence times. Repeated steady-state assessments of the righting reflex obtained during the last 2 h of a 4-h exposure to 0.3, 0.4, 0.6, or 0.7 vol% isoflurane (n=20 per concentration) were used to determine individual probabilities of losing the righting reflex, which was defined as an individual's anaesthetic sensitivity.

RESULTS

Emergence times varied by at least two orders of magnitude after identical anaesthetic exposure. We did not find consistent inter-individual differences in emergence times. Instead, we found that variability in emergence times across trials in each individual was as large as that between two different individuals. Emergence times were not correlated across time. Consistent with previous work, we identified large individual differences in anaesthetic sensitivity which persisted on a time scale of at least 1 week. A standard PK-PD model failed to reproduce inter-trial variability. In contrast, the neuronal dynamics model reproduced both population- and individual-level variability in emergence times.

CONCLUSIONS

Stochastic state switching contributes to inherent variability in emergence from general anaesthesia. Delayed emergence occurred in a small proportion of anaesthetic exposures in a genetically homogeneous population. The neuronal dynamics model predicts that anaesthetic emergence times will be probabilistically long, which might explain delayed emergence observed in clinical settings.

Electroencephalogram Correlates of Delayed Emergence After Remimazolam-Induced Anesthesia Compared to Propofol

BACKGROUND

Delayed emergence from anesthesia presents clinical challenges, including prolonged stays in the postanesthesia care unit (PACU). The neurobiological mechanisms underlying delayed emergence, particularly in remimazolam-induced anesthesia, remain poorly understood. This study aimed to explore patterns of brain electrical activity of delayed emergence in remimazolam-induced anesthesia by comparing dynamic changes in electroencephalogram (EEG) activity under various anesthesia states of remimazolam and propofol, focusing on the prefrontal region.

METHODS

Forty-eight patients (age >18) who underwent laparoscopic cholecystectomy randomly received remimazolam- or propofol-induced general anesthesia. Power spectrogram analysis and functional connectivity measures, phase lag entropy (PLE) and phase lag index (PLI), were used to the prefrontal EEG data collected at baseline, unconsciousness, and emergence. Correlation between EEG measures and Patient State Index (PSI) at PACU, as well as time to Aldrete 9, were compared.

RESULTS

During emergence from anesthesia, EEG power revealed that the remimazolam group had higher powers than the propofol group in theta band during eyes-open (EO) (mean of 2.933 [standard deviation of 5.762] vs -2.342 [4.869]; P-value of 0.018 with independent 2-sample t test), and in the alpha band during eyes-closed (EC) (5.821 [7.35] vs -2.399 [4.53]; P < .001) and EO (4.84 [6.411] vs -3.613 [4.556]; P < .001). Conversely, the functional connectivity result showed lower PLE in the alpha band during EC (0.619 [0.0338] vs 0.684 [0.0392]; P < .0001) and EO (0.651 [0.0358] vs 0.692 [0.0428]; P = .015), and in the beta band during EC (0.682 [0.0308] vs 0.712 [0.0236]; P = .016) and EO (0.695 [0.0236] vs 0.725 [0.0195]; P < .001). In line with this, the remimazolam group had lower PSI values at PACU during EC (65.10 [14.67] vs 82.40 [6.678]; P < .0001) and EO (72.35 [12.55] vs 83.53 [6.632]; P = .006) and were slower to reach Aldrete score of 9 (median difference of 17.5; interquartile range of [0.0-21.0]; P < .001). Delayed consciousness recovery (time to Aldrete 9) under remimazolam was significantly correlated with PLE (Pearson's correlation = -.78, P < .0001) and PLI (Pearson's correlation =.69, P = .028) in the alpha band during deep anesthesia.

CONCLUSIONS

Dynamic changes in prefrontal EEG during recovery and the correlation analyses show the potential of EEG in reflecting distinct consciousness recovery profiles between 2 drugs-slower recovery under remimazolam anesthesia. This suggests an association of EEG parameters with a unique behavioral profile of remimazolam, especially reflecting progressive changes in cerebral activity during recovery.

Profoundly Delayed Emergence due to Pulmonary Embolism

Pulmonary embolism is a rare, but serious, potential perioperative complication and crisis. We present a case of a 12-year-old female undergoing distal femoral and proximal tibial osteotomies with internal fixations who experienced acute onset hypercapnia, tachycardia, and prolonged minimal responsiveness following deflation of the tourniquet and cessation of inhaled sevoflurane. CT-chest demonstrated bilateral partially occlusive filling defects of the pulmonary vasculature. We concluded that the patient experienced a pulmonary embolism resulting in V/Q mismatch, retained sevoflurane, and ultimately delayed emergence.

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.

The effect of continuous positive airway pressure (CPAP) application on airway problems in pediatric patients with subglottic stenosis who undergo balloon dilatation

BACKGROUND

Subglottic stenosis is a significant clinical challenge in pediatric anesthesia, often necessitating interventions that can lead to various postoperative complications. The aim of this study was to determine the effect of prophylactic continuous positive airway pressure (CPAP) application on recovery time and airway complications in pediatric patients with subglottic stenosis undergoing balloon dilatation.

METHODS

A prospective, double-blinded, parallel-group, randomized controlled study was conducted at Health Sciences University Ümraniye Training and Research Hospital on pediatric patients with subglottic stenosis, aged from 0 to 12 years and who underwent elective balloon dilatation under general anesthesia. Patients were randomized in a 1:1 ratio into the CPAP or non-CPAP group. The primary outcome was the duration of recovery time. Secondary outcomes included bronchospasm, the number of desaturation episodes, intubation, tracheostomy, and the need for intensive care.

RESULTS

A total of 84 patients were enrolled in this randomized controlled trial, 81 of which received the allocated treatment and were analyzed (non-CPAP n = 41, CPAP n = 40). Compared to controls, the proportions of bronchospasm, tracheal secretion, need for intensive care, and tracheostomy were consistently lower in the CPAP group, whereas the requirement of intubation was higher. Further, the mean recovery time was significantly shorter in the CPAP group compared to the non-CPAP group (mean difference - 3.3 min, 95%CI - 5.16 to - 1.44, p = 0.0007). Despite lacking statistical significance, the CPAP group had reduced odds of developing bronchospasm, tracheal secretion, need for intensive care, and tracheostomy, but higher odds of requiring intubation when compared to the controls.

CONCLUSION

Prophylactic CPAP application following therapeutic balloon dilatation in pediatric patients who have developed subglottic stenosis due to acquired or congenital causes appears to effectively shorten recovery time and may have a role in decreasing postoperative pulmonary complications; however, more research is recommended to further confirm these findings.

TRIAL REGISTRATION

The protocol for this clinical trial was retrospectively registered on clinicaltrials.gov with registration ID NCT06183515 on 30 November 2023.

Discovery of thioetomidate derivatives as rapid recovery hypnotics without adrenocortical suppression

Intravenous anesthetics play a crucial role during surgery. Etomidate, a commonly used intravenous anesthetic agent, is prized for its rapid onset and smooth induction of anesthesia. However, it has a pronounced adverse effect on adrenal function suppression. To obtain new rapid recovery hypnotic agents without adrenocortical suppression, a series of thioetomidate derivatives (TET-1-TET-14) were designed and synthesized. Among them, TET-13 (half-live T1/2 = 0.48 min) was metabolized much faster than that of etomidate (T1/2 = 26 min) in rat plasma. In rodents, TET-13 exhibited potent anesthetic effects in both mice (ED50 = 0.48 mg/kg) and rats (ED50 = 0.69 mg/kg) and demonstrated a markedly shorter recovery time compared to etomidate. In the GABAAR binding assay, TET-13 acted as a positive allosteric modulator on the GABAA receptor and showed an EC50 of 5.65 μM which was lower than etomidate (EC50 = 9.29 μM). At equivalent doses, TET-13 group showed significantly less adrenocortical suppression than etomidate. Moreover, in the continuous infusion test, the time to behavioral recovery and time to walk after infusion with TET-13 were all shorter than etomidate. Thioetomidate derivatives represent a promising strategy to develop new rapid recovery hypnotic agents without adrenocortical suppression.

A Case Report on an Unknown Etiology Disorder of Consciousness Following Extubation Despite Thorough Evaluation

Postoperative disorders of consciousness can arise from various factors, making diagnosis challenging. This report presents a case of a disorder of consciousness that occurred after awakening from general anesthesia, in which various examinations including computed tomography (CT) and magnetic resonance imaging (MRI) were conducted, but the cause could not be identified. A man in his 60s with a history of hypertension and cerebral hemorrhage underwent revision total hip arthroplasty under general anesthesia for a left periprosthetic hip fracture. The induction and maintenance of anesthesia were uneventful. Postoperatively, anesthesia was discontinued, and the patient responded to verbal commands, opened his eyes, and was able to follow handgrip instructions, allowing for extubation. However, after moving to the recovery room, his level of consciousness decreased, reaching a Glasgow Coma Scale score of E3V1M3-4. Suspecting prolonged effects of the anesthetic agents, his condition was observed in the recovery room for approximately 30 minutes, but there was no change in his level of consciousness. CT and MRI of the head were performed, but no significant abnormalities were found. Electroencephalogram monitoring did not show any clear epileptiform activity. Gradual improvement in his level of consciousness was noted 60-120 minutes after the initial decline. Subsequently, there were no further episodes of disordered consciousness. Perioperative disorders of consciousness are challenging to diagnose due to the potential effects of anesthetic agents. Although the cause could not be identified in this case, the patient fortunately recovered consciousness without any significant sequelae.

Development and validation of a prediction model for delayed recovery from anesthesia in elderly lung adenocarcinoma patients underwent thoracoscopic radical resection

This study aimed to develop and validate a risk prediction model based on real-world data to assess the risk of delayed recovery from anesthesia in elderly lung adenocarcinoma patients underwent video-assisted thoracoscopic (VATS) radical resection. This study is a retrospective study of real-world data. A total of 257 elderly lung adenocarcinoma patients who underwent VATS radical resection from January 2022 to December 2023 in a tertiary hospital in Wuhan were selected. Patients were divided into delayed recovery (n = 42) and non- delayed recovery group (n = 215) according to whether delayed recovery occurred after anesthesia. Lasso regression was used to screen the independent variables. Logistic regression was used to analyze the risk factors of delayed recovery from anesthesia, and a nomogram model was established. Bootstrap method was used to internally verify the nomogram model. Delayed recovery from anesthesia occurred in 42 of 257 elderly lung adenocarcinoma patients underwent VATS radical resection (16.34%). Logistic regression analysis showed that anesthesia duration, intraoperative infusion volume, inhaled desflurane, preoperative respiratory tract infection, intraoperative hypothermia and diagnosed with hypertension were risk factors for delayed recovery from anesthesia in elderly lung adenocarcinoma patients underwent VATS radical resection (P < 0.05). The area under receiver operating characteristic curve was 0.869, 95% CI (0.815 ~ 0.923). The optimal cutoff value was 0.198, the sensitivity was 0.738, and the specificity was 0.823. Hosmer-Lemeshow test showed that χ2 = 7.346, P = 0.500. The decision curve analysis results have shown that the threshold probability is between 0.23 and 0.91, and the net benefit rate of the model is good. The risk prediction model constructed in this study can provide reference for medical staff to screen precisely high-risk of delayed recovery from anesthesia in elderly lung adenocarcinoma patients underwent VATS radical resection, which is of great significance.

Correlation of Preoperative Hippocampal Volume Measured with Magnetic Resonance Imaging and Emergence from General Anaesthesia in Elective Neurosurgical Patients: An Observational Study

BACKGROUND AND OBJECTIVES

The electrophysiological process of emergence from general anesthesia (GA) commences from deeper structures of the brain rather than the cortex. The phylogenetically old parts of the brain (hippocampus) are the first to recover during emergence. Study objectives were to evaluate and predict the effect of preoperative hippocampal volume (HV) measured using MRI with emergence from GA and delayed extubation in patients undergoing elective neurosurgical procedures.

METHODS

Patients aged 18-65 years of age scheduled for elective neurosurgical procedures under GA with GCS = 15 were recruited into the prospective cohort. Those who underwent excision of the hippocampus, amygdala, and temporal lobe pathology were excluded. Bilateral HVs and total brain volume were measured preoperatively using MRI brain. GA was induced by thiopentone, fentanyl, and vecuronium and maintained with sevoflurane. At the end of the surgery, sevoflurane was turned off, and a fresh gas flow of 6 L min-1 oxygen was set, allowing patients to wake up by "no contact technique." Time elapsed from turning off sevoflurane till the onset of different phases of emergence was measured. The patterns of emergence were assessed using GCS and Riker Sedation-Agitation Scale.

RESULTS

The complete data of 125 patients of 1192 screened for recruitment were analyzed. The median time for extubation was 13 minutes (IQR 9-16). The average bilateral standardized HV had a statistically significant negative correlation with the time to extubation (r = -0.185; P = 0.039). Average of bilateral standardized HV <2097 mm3 predicts delayed extubation with a specificity: 70.7%, sensitivity: 51.2% and AUC: 0.672, CI 0.524-0.724. Standardized dominant HV <1925 mm3 also predicts delayed extubation with specificity: 78%, sensitivity: 46.4% and AUC: 0.635, CI 0.533-0.738.

CONCLUSION

Neurosurgical patients with larger average HV might lead to early extubation, vocalization, and faster gaining of orientation after GA.

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.

Sunset Sign Due to Intraventricular Tension Pneumocephalus: A Key Clue to Evaluating Delayed Emergence After General Anesthesia

Prompt emergence from general anesthesia is crucial after neurosurgical procedures, such as craniotomies, to facilitate timely neurological evaluation for identification of intraoperative complications. Delayed emergence can be caused by residual anesthetics, metabolic imbalances, and intracranial pathology, for which an eye examination can provide early diagnostic clues. The sunset sign (or setting sun sign), characterized by a downward deviation of the eyes, can be an early indicator of raised intracranial pressure (ICP) or midbrain compression, as is commonly observed in states of hydrocephalus or periaqueductal or tectal plate dysfunction. A 50-year-old woman with a history of headaches, diplopia, and Parinaud syndrome presented with a pineal mass and underwent an occipital and suboccipital craniotomy with endoscopically-assisted tumor resection. The procedure was managed with neurophysiological monitoring to detect surgical compromise on neurophysiological function. An external ventricular drain (EVD) was placed for cerebrospinal fluid (CSF) drainage to facilitate brain relaxation and operative intervention. Blood loss was estimated to be 200 ml. Thirty minutes after surgery, the patient did not open her eyes to verbal commands despite the cessation of anesthetics significantly earlier. Eye examination revealed an intermittent downward gaze, recognized as the sunset sign. Arterial blood gas results and metabolic parameters were within normal limits, shifting the focus to possible intracranial complications as the source of her delayed emergence. Consequently, an emergent head computer tomography (CT) was ordered, and the EVD was clamped and not monitored for transport. The CT scan revealed tension pneumocephalus compressing the midbrain. The patient was transferred to the neurocritical care unit, where the admission ICP measured from the EVD was 50 mmHg. Initial critical care treatment included maintaining sedation, CSF drainage via the EVD, 100% oxygen, and head of bed at zero degrees. The patient underwent an MRI brain approximately six hours post-operatively, revealing restricted diffusion in the bilateral medial thalamic regions. The patient was successfully extubated on postoperative day one. Over the following 48 hours, the sunset sign disappeared, the tension pneumocephalus resolved, ICP normalized, and the patient's neurological status gradually improved. Delayed emergence after neurosurgical procedures can be multifactorial, and eye movement abnormalities like the sunset sign can offer early diagnostic clues. In this case, the sunset sign occurred from elevated ICP due to tension pneumocephalus, a rare but serious postoperative complication. Early recognition of the sunset sign and immediate neuroimaging allowed for prompt relief of intracranial hypertension, highlighting the importance of incorporating detailed ocular assessments into postoperative evaluations. The sunset sign is an important clinical marker of increased ICP and midbrain dysfunction, warranting urgent investigation. This case underscores the need for early, thorough postoperative assessment, including eye examination, to identify and manage potential complications that may delay emergence from general anesthesia. Eye examination may be warranted as part of routine neurological evaluation during emergence from general anesthesia.

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.

Post-Anesthesia Recovery: A Comprehensive Review of Sampe, Modified Aldrete, and White Scoring Systems

Post-anesthesia recovery is a vital phase in the perioperative continuum, where the quality of care and monitoring heavily influence patient outcomes. This comprehensive review examines the Sampe, Modified Aldrete, and White Scoring Systems, pivotal in evaluating patients' readiness for discharge from the Post-Anesthesia Care Unit (PACU). The review delves into the historical evolution of post-anesthesia care, highlighting the transition from minimal post-operative support to the establishment of PACUs and the subsequent development of structured recovery scoring systems. Each scoring system is analyzed in detail, focusing on its components, criteria, scoring methodology, advantages, and limitations. A comparative analysis underscores these systems' similarities and differences, sensitivity, specificity, and practical applications in clinical settings. Additionally, the review discusses the clinical implications of these scoring systems in enhancing patient management, improving safety, and ensuring standardized care. Emerging technologies and future directions in recovery assessment are also explored, providing insights into potential innovations. This review aims to equip healthcare professionals with a deeper understanding of these scoring systems, facilitating informed decisions to optimize post-anesthesia care and patient outcomes.

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.