Delayed emergence after anesthesia

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.

Neurobiological basis of emergence from anesthesia

The suppression of consciousness by anesthetics and the emergence of the brain from anesthesia are complex and elusive processes. Anesthetics may exert their inhibitory effects by binding to specific protein targets or through membrane-mediated targets, disrupting neural activity and the integrity and function of neural circuits responsible for signal transmission and conscious perception/subjective experience. Emergence from anesthesia was generally thought to depend on the elimination of the anesthetic from the body. Recently, studies have suggested that emergence from anesthesia is a dynamic and active process that can be partially controlled and is independent of the specific molecular targets of anesthetics. This article summarizes the fundamentals of anesthetics' actions in the brain and the mechanisms of emergence from anesthesia that have been recently revealed in animal studies.

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.

Esketamine accelerates emergence from isoflurane general anaesthesia by activating the paraventricular thalamus glutamatergic neurones in mice

BACKGROUND

Delayed emergence from general anaesthesia poses a significant perioperative safety hazard. Subanaesthetic doses of ketamine not only deepen anaesthesia but also accelerate recovery from isoflurane anaesthesia; however, the mechanisms underlying this phenomenon remain elusive. Esketamine exhibits a more potent receptor affinity and fewer adverse effects than ketamine and exhibits shorter recovery times after brief periods of anaesthesia. As the paraventricular thalamus (PVT) plays a pivotal role in regulating wakefulness, we studied its role in the emergence process during combined esketamine and isoflurane anaesthesia.

METHODS

The righting reflex and cortical electroencephalography were used as measures of consciousness in mice during isoflurane anaesthesia with coadministration of esketamine. The expression of c-Fos was used to determine neuronal activity changes in PVT neurones after esketamine administration. The effect of esketamine combined with isoflurane anaesthesia on PVT glutamatergic (PVTGlu) neuronal activity was monitored by fibre photometry, and chemogenetic technology was used to manipulate PVTGlu neuronal activity.

RESULTS

A low dose of esketamine (5 mg kg-1) accelerated emergence from isoflurane general anaesthesia (474 [30] s vs 544 [39] s, P=0.001). Esketamine (5 mg kg-1) increased PVT c-Fos expression (508 [198] vs 258 [87], P=0.009) and enhanced the population activity of PVTGlu neurones (0.03 [1.7]% vs 6.9 [3.4]%, P=0.002) during isoflurane anaesthesia (1.9 [5.7]% vs -5.1 [5.3]%, P=0.016) and emergence (6.1 [6.2]% vs -1.1 [5.0]%, P=0.022). Chemogenetic suppression of PVTGlu neurones abolished the arousal-promoting effects of esketamine (459 [33] s vs 596 [33] s, P<0.001).

CONCLUSIONS

Our results suggest that esketamine promotes recovery from isoflurane anaesthesia by activating PVTGlu neurones. This mechanism could explain the rapid arousability exhibited upon treatment with a low dose of esketamine.

Risk factors for delayed recovery in postanesthesia care unit after surgery: a large and retrospective cohort study

BACKGROUND

Delayed recovery in the postanesthesia care unit (PACU) after surgery, as a severe occurrence, influences enhanced recovery after surgery. The data from the observational clinical study is a paucity.

MATERIALS AND METHODS

This large, retrospective, and observational cohort study initially included 44 767 patients. The primary outcome was risk factors for delayed recovery in PACU. A generalized linear model and nomogram were employed to identify risk factors. Discrimination and calibration were used to evaluate the performance of the nomogram via internal and external validation.

RESULTS

Of 38 796 patients, 21 302 (54.91%) were women. The delayed recovery aggregate rate was 1.38% [95% CI, (1.27, 1.50%)]. In a generalized linear model, risk factors for delayed recovery were old age [RR, 1.04, 95% CI, (1.03,1.05), P <0.001], neurosurgery [RR, 2.75, 95% CI, (1.60, 4.72), P <0.001], using antibiotics during surgery [RR, 1.30, 95% CI, (1.02, 1.66), P =0.036], long anesthesia duration [RR, 1.0025, 95% CI, (1.0013, 1.0038), P <0.001], ASA grade of III [RR, 1.98, 95% CI, (1.38, 2.83), P <0.001], and postoperative analgesia [RR, 1.41, 95% CI, (1.10, 1.80), P =0.006]. In the nomogram, old age and neurosurgery had high scores in the model and contributed significantly to the increased probability of delayed recovery. The area under the curve value of the nomogram was 0.77. The discrimination and calibration of the nomogram estimated by internal and external validation were generally satisfactory.

CONCLUSION

This study demonstrates that delayed recovery in PACU after surgery was associated with old age, neurosurgery, long anesthesia duration, an ASA grade of III, using antibiotics during surgery, and postoperative analgesia. These findings provide predictors of delayed recovery in PACU, especially neurosurgeries and old age.

[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.

[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.

Delayed diagnosis of butyrylcholinesterase deficiency with insufficient neuromuscular monitoring and a confounding effect of SedLine® brain function monitoring: a case report

Intraoperative monitoring has always been a vital part of the care of an anaesthetised patient. Neuromuscular monitoring is important to use when patients have received neuromuscular blocking agents. Quantitative neuromuscular monitors are preferred over qualitative monitors and clinical judgement alone in reducing residual neuromuscular block and the associated respiratory complications. Additionally, brain function monitors can be utilised to assess the level of consciousness in anaesthetised patients. These monitors can be useful during surgical procedures and at the conclusion of a procedure to show the progress of a patient emerging from anaesthesia. We describe a case where a lack of neuromuscular monitoring after a single dose of succinylcholine coupled with an overemphasis on SedLine® brain function monitor values delayed the diagnosis of butyrylcholinesterase deficiency in a patient undergoing a mastectomy for breast cancer. This case shows the fundamental importance of using neuromuscular monitors in patients who receive neuromuscular blocking agents. It also stresses the necessity to utilise brain function monitors as clinical aids, but not allow them to hinder thinking about broader differential diagnoses when faced with challenging clinical scenarios.

Does surgical plethysmographic index-guided analgesia affect opioid requirement and extubation time? A systematic review and meta-analysis

Purpose

This meta-analysis of all relevant clinical trials investigated surgical plethysmographic index (SPI)-guided analgesia’s efficacy under general anesthesia for perioperative opioid requirement and emergence time after anesthesia.

Methods

PubMed, Embase, Web of Science, and Cochrane Library were searched up to January 2022 to identify clinical trials comparing SPI-guided and conventional clinical practice for patients who underwent general anesthesia. With the random-effects model, we compared intraoperative opioid consumption, emergence time, postoperative pain, analgesia requirement, and incidence of postoperative nausea and vomiting (PONV).

Results

Thirteen randomized controlled trials (RCTs) (n = 1314) met our selection criteria. The overall pooled effect sizes of all RCTs indicated that SPI-guided analgesia could not significantly reduce opioid consumption during general anesthesia. SPI-guided analgesia accompanied with hypnosis monitoring could decrease intraoperative opioid consumption (standardized mean difference [SMD] − 0.31, 95% confidence interval [CI] − 0.63 to 0.00) more effectively than SPI without hypnosis monitoring (SMD 1.03, 95% CI 0.53–1.53), showing a significant difference (p < 0.001). SPI-guided analgesia could significantly shorten the emergence time, whether assessed by extubation time (SMD − 0.36, 95% CI − 0.70 to − 0.03, p < 0.05, I² = 67%) or eye-opening time (SMD − 0.40, 95% CI − 0.63 to − 0.18, p < 0.001, I² = 54%). SPI-guided analgesia did not affect the incidence of PONV, postoperative pain, and analgesia management.

Conclusion

SPI-guided analgesia under general anesthesia could enhance recovery after surgery without increasing the postoperative complication risk. However, it did not affect intraoperative opioid requirement. Notably, SPI-guided analgesia with hypnosis monitoring could effectively reduce intraoperative opioid requirement.

Effect of Different Vitamin D Levels on Cognitive Function in Aged Mice After Sevoflurane Anesthesia

Although the biological relationship between vitamin D (VD) deficiency and cognitive function has been recognized by many scholars, the theoretical mechanisms involved are still not well-understood. In this study, we demonstrated the role of VD in alleviating the cognitive dysfunction in aged mice caused by sevoflurane anesthesia. Forty female C57BL/6 mice aged 12 months were selected for the experiment. VD (-) and VD (+) mouse models and sevoflurane anesthesia models were established. Mice were randomly divided into normal elderly group (NC group), normal aged mice + sevoflurane anesthesia treatment group (NS group), aged VD (-) mice + sevoflurane anesthesia treatment group [VD (-) group], and aged VD (+) + sevoflurane anesthesia treatment group [VD (+) group]. To compare the emergence time after sevoflurane anesthesia in aged mice with different levels of VD and to test the cognitive function of four groups through the water maze. Inflammatory factor expression and cholinergic activity in hippocampus tissue of all mice were measured at the end of behavioral tests. These data show that, low levels of VD aggravated the delayed emergence and cognitive dysfunction in aged mice caused by sevoflurane anesthesia, while higher levels of VD mitigated this impairment by enhancing cholinergic activity and reducing inflammatory factor expression in the hippocampus.

Defining the Time Benefit of Awake Versus General Anesthesia for Single-Level Lumbar Spine Surgery

BACKGROUND

Awake anesthesia with monitored anesthesia care (MAC) might confer time benefits compared with traditional general anesthesia (GA) in the setting of single-level lumbar spine surgery. Therefore, we sought to define the quantitative time difference spent in the operating room between the MAC and GA approaches for single-level lumbar spine surgery.

METHODS

A prospectively maintained database of the senior surgeon was reviewed for single-level lumbar spine surgeries from 2019 to 2020 performed with the patient under either GA or MAC. The patient demographics, clinical features, time in the operating room, and postoperative outcomes were all summarized and statistically compared.

RESULTS

A total of 53 patients satisfied all the selection criteria, with 25 (47%) in the GA group and 28 (53%) in the MAC group. Overall, most patients were men, with a median age of 60 years. The 2 groups were statistically comparable with respect to the demographics and preoperative anesthesia parameters. The time from room arrival to sedation start (median time, 26 vs. 38 minutes; P < 0.01), sedation time (median time, 55 vs. 87 minutes; P < 0.01), and time from sedation end to room exit (median time, 4 vs. 13 minutes; P < 0.01) were all significantly shorter for the MAC group. Additionally, the estimated blood loss was less in the MAC group (P < 0.01).

CONCLUSIONS

We found MAC to be a safe anesthesia option for use in single-level lumbar spine surgery, which led to statistically significant benefits regarding the time under sedation and time in the operating room compared with GA. Future studies are required to understand whether MAC will require other synergistic measures to generate observable change at a health systems level.

Predictors for time to awake in patients undergoing awake craniotomies

OBJECTIVE

Awake craniotomies are often characterized by alternating asleep-awake-asleep periods. Preceding the awake phase, patients are weaned from anesthesia and mechanical ventilation. Although clinicians aim to minimize the time to awake for patient safety and operating room efficiency, in some patients, the time to awake exceeds 20 minutes. The goal of this study was to determine the average time to awake and the factors associated with prolonged time to awake (> 20 minutes) in patients undergoing awake craniotomy.

METHODS

Records of patients who underwent awake craniotomy between 2003 and 2020 were evaluated. Time to awake was defined as the time between discontinuation of propofol and remifentanil infusion and the time of extubation. Patient and perioperative characteristics were explored as predictors for time to awake using logistic regression analyses.

RESULTS

Data of 307 patients were analyzed. The median (IQR) time to awake was 13 (10-20) minutes and exceeded 20 minutes in 17% (95% CI 13%-21%) of the patients. In both univariate and multivariable analyses, increased age, nonsmoker status, and American Society of Anesthesiologists (ASA) class III versus II were associated with a time to awake exceeding 20 minutes. BMI, as well as the use of alcohol, drugs, dexamethasone, or antiepileptic agents, was not significantly associated with the time to awake.

CONCLUSIONS

While most patients undergoing awake craniotomy are awake within a reasonable time frame after discontinuation of propofol and remifentanil infusion, time to awake exceeded 20 minutes in 17% of the patients. Increasing age, nonsmoker status, and higher ASA classification were found to be associated with a prolonged time to awake.

New Serotonin-Norepinephrine Reuptake Inhibitors and Their Anesthetic and Analgesic Considerations

Serotonin-norepinephrine reuptake inhibitors (SNRIs) inhibit the presynaptic neuronal uptake of serotonin and norepinephrine and prolong the effects of the monoamines in the synaptic cleft within the central nervous system, leading to increased postsynaptic receptor activation and neuronal activities. Serotonin-norepinephrine reuptake inhibitors can have multiple clinical indications, including as the first-line agents for the management of depression and anxiety, and as analgesics in the treatment of chronic pain. The effects of reuptake inhibition of norepinephrine and serotonin are often dose-dependent and agent-dependent. There are five FDA-approved serotonin-norepinephrine reuptake inhibitors (desvenlafaxine, duloxetine, levomilnacipran, milnacipran and sibutramine) currently being marketed in the United States. As the COVID-19 pandemic significantly increased the incidence and prevalence of anxiety and depression across the country, there are significantly increased prescriptions of these medications perioperatively. Thus, anesthesiologists are more likely than ever to have patients administered with these agents and scheduled for elective or emergency surgical procedures. A thorough understanding of these commonly prescribed serotonin-norepinephrine reuptake inhibitors and their interactions with commonly utilized anesthetic agents is paramount. There are two potentially increased risks related to the continuation of SNRIs through the perioperative period: intraoperative bleeding and serotonin syndrome. SNRIs have some off-label uses, more new indications, and ever-increasing new applications in perioperative practice. This article aims to review the commonly prescribed serotonin-norepinephrine reuptake inhibitors and the current clinical evidence regarding their considerations in perioperative anesthesia and analgesia.

D-Amphetamine Rapidly Reverses Dexmedetomidine-Induced Unconsciousness in Rats

D-amphetamine induces emergence from sevoflurane and propofol anesthesia in rats. Dexmedetomidine is an α₂-adrenoreceptor agonist that is commonly used for procedural sedation, whereas ketamine is an anesthetic that acts primarily by inhibiting NMDA-type glutamate receptors. These drugs have different molecular mechanisms of action from propofol and volatile anesthetics that enhance inhibitory neurotransmission mediated by GABA_A receptors. In this study, we tested the hypothesis that d-amphetamine accelerates recovery of consciousness after dexmedetomidine and ketamine. Sixteen rats (Eight males, eight females) were used in a randomized, blinded, crossover experimental design and all drugs were administered intravenously. Six additional rats with pre-implanted electrodes in the prefrontal cortex (PFC) were used to analyze changes in neurophysiology. After dexmedetomidine, d-amphetamine dramatically decreased mean time to emergence compared to saline (saline:112.8 ± 37.2 min; d-amphetamine:1.8 ± 0.6 min, p < 0.0001). This arousal effect was abolished by pre-administration of the D₁/D₅ dopamine receptor antagonist, SCH-23390. After ketamine, d-amphetamine did not significantly accelerate time to emergence compared to saline (saline:19.7 ± 18.0 min; d-amphetamine:20.3 ± 16.5 min, p = 1.00). Prefrontal cortex local field potential recordings revealed that d-amphetamine broadly decreased spectral power at frequencies <25 Hz and restored an awake-like pattern after dexmedetomidine. However, d-amphetamine did not produce significant spectral changes after ketamine. The duration of unconsciousness was significantly longer in females for both dexmedetomidine and ketamine. In conclusion, d-amphetamine rapidly restores consciousness following dexmedetomidine, but not ketamine. Dexmedetomidine reversal by d-amphetamine is inhibited by SCH-23390, suggesting that the arousal effect is mediated by D₁ and/or D₅ receptors. These findings suggest that d-amphetamine may be clinically useful as a reversal agent for dexmedetomidine.

Delayed awakening with apnea as a sign of cerebellar hemorrhage after vestibular schwannoma surgery: A case report

Cerebellar hemorrhage after surgery is a rare but critical complication requiring prompt diagnosis and intervention. However, anesthetics can mask most brain compression signs. Prolonged coma with apnea after tumor resection under general anesthesia may indicate the need for prompt imaging to detect or exclude cerebellar lesions.

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

The emergence from anesthesia is the stage of general anesthesia featuring the patient’s progression from the unconsciousness status to wakefulness and restoration of consciousness. This complex process has precise neurobiology which differs from that of induction. Despite the medications commonly used in anesthesia allow recovery in a few minutes, a delay in waking up from anesthesia, called delayed emergence, may occur. This phenomenon is associated with delays in the operating room, and an overall increase in costs. Together with the emergence delirium, the phenomenon represents a manifestation of inadequate emergence. Nevertheless, in delayed emergence, the transition from unconsciousness to complete wakefulness usually occurs along a normal trajectory, although slowed down. On the other hand, this awakening trajectory could proceed abnormally, possibly culminating in the manifestation of emergence delirium. Clinically, delayed emergence often represents a challenge for clinicians who must make an accurate diagnosis of the underlying cause to quickly establish appropriate therapy. This paper aimed at presenting an update on the phenomenon, analyzing its causes. Diagnostic and therapeutic strategies are addressed. Finally, therapeutic perspectives on the “active awakening” are reported.

Use of Emergency Manuals to Treat Delayed Emergence After Robotic-Assisted Cholecystectomy

Delayed emergence is defined as failure to regain consciousness 30 to 60 minutes after general anesthesia. Although incidence is low and difficult to accurately estimate, there is a wide differential diagnosis to be considered. Emergency manuals (EMs) are visual cognitive aids that can be used in the operating room to help manage intraoperative complications. They provide immediate access to evidence-based guidelines to optimize management of intraoperative complications. They are being increasingly implemented in the clinical setting and have been shown to improve patient safety. A case of a patient with delayed emergence after undergoing robotic-assisted cholecystectomy is described here. The delayed emergence section of the Stanford Anesthesia Emergency Model was referenced immediately and guided management of the patient. Utilization of an EM resulted in rapid return to baseline mental status. EMs allow health care providers to respond to intraoperative scenarios efficiently and effectively and ultimately improve patient care.

The risk factors for postoperative cerebral complications in patients with Stanford type a aortic dissection

Background

Postoperative cerebral complications (PCC) are common and serious postoperative complications for patients with Stanford type A aortic dissection (AAD). The aim of this study was to evaluate the risk factors for PCC in these patients and to provide a scientific basis for effective prevention of PCC.

Methods

In this retrospective case-control study, 125 patients with AAD who underwent thoracotomy in our department from October 2017 to October 2018 in the department of cardiovascular surgery, Fujian Medical University Union Hospital were divided into two groups: patients with PCC (n = 12), and patients without PCC (n = 113). The general clinical data, the types of corrective surgeries, the intraoperative situations, the postoperative complications, and the midterm outcomes of the patients were analyzed.

Results

The patients with PCC were significantly older than the patients without PCC (P = 0.016), and the incidence of the preoperative cerebral disease history in the patients with PCC was significantly higher than those of the PCC (−) group (P = 0.024). The Euro SCORE II of patients with PCC was dramatically higher than the patients without PCC (P = 0.005). There were significant differences between the two groups in terms of the duration of cardiopulmonary bypass (CPB) (P = 0.010) and the length of moderate hypothermic circulatory arrest (MHCA) combined with selective cerebral perfusion (SCP) (P = 0.000). The monitoring of rcSO₂ indicated that there was significant difference between the two groups in terms of the bilateral baseline (P = 0.000). Patients with PCC were observed to have experienced significantly longer intubation times (P = 0.000), ICU stays (P = 0.001), and postoperative hospital stays (P = 0.009), and they also had dramatically higher rates of pulmonary infection (P = 0.000), multiple organ dysfunction syndrome (P = 0.041) and tracheotomy (P = 0.022) after surgeries. The duration of MHCA+SCP (OR:9.009, P = 0.034) and the average baseline value of rcSO₂ (OR:0.080, P = 0.009) were ultimately identified as significant risk factors.

Conclusions

PCC has a serious influence on the prognoses of patients following surgical treatment with AAD. The duration of MHCA+SCP and the average baseline value of rcSO₂ were the independent risk factors for PCC.

Intracranial Space-occupying Lesion Inducing Intracranial Hypertension Increases the Encephalographic Effects of Isoflurane in a Swine Model

BACKGROUND

Patients with a brain tumor are susceptible to the hypnotic effect of anesthetics depending on the tumor's size. We investigated whether intracranial space-occupying lesions (ICSOLs) inducing intracranial hypertension increase isoflurane's effect on electroencephalographic (EEG) results.

MATERIALS AND METHODS

After anesthetic induction with isoflurane, 11 swine were studied with regard to isoflurane's effect on EEGs at 0.5% to 2.0% inhalational concentration at sequential stages: baseline 1, ICSOL 1, baseline 2, ICSOL 2, baseline 3. At each ICSOL stage, an intracranial epidural balloon catheter was inflated and the intracranial pressure maintained at twice the baseline pressure. The balloon was deflated after each ICSOL stage (baselines 2 and 3). A 95% spectral edge frequency (SEF), which correlates with anesthetic hypnosis, was used to measure isoflurane's effect. Pharmacodynamics was characterized using a sigmoidal inhibitory maximum effect model for the SEF versus end-tidal concentration.

RESULTS

ICSOL shifted the relations between SEF and the effect-site concentration (Ce) downward. Baseline and 50% of the maximum spectral edge effect levels significantly decreased during balloon inflation. The Ce that produced SEF=15 was 1.12 (1.04-1.20) (mean [95% confidence interval])% for baseline 1; 0.92 (0.81-1.03) for ICSOL 1; 1.02 (0.94-1.11) for baseline 2; 0.88 (0.82-0.94) for ICSOL 2; 1.05 (0.93-1.17) for baseline 3. Isoflurane's effect on EEGs increased during balloon inflation, with the alteration tending to recover after balloon deflation.

CONCLUSIONS

ICSOLs inducing intracranial hypertension increase the EEG effect of isoflurane, and external compression from the brain surface enhances the anesthetic hypnosis despite minimum brain injury.

Cognitive Aids for the Diagnosis and Treatment of Neuroanesthetic Emergencies: Consensus Guidelines on Behalf of the Society for Neuroscience in Anesthesiology and Critical Care (SNACC) Education Committee

Cognitive aids and evidence-based checklists are frequently utilized in complex situations across many disciplines and sectors. The purpose of such aids is not simply to provide instruction so as to fulfill a task, but rather to ensure that all contingencies related to the emergency are considered and accounted for and that the task at hand is completed fully, despite possible distractions. Furthermore, utilization of a checklist enhances communication to all team members by allowing all stakeholders to know and understand exactly what is occurring, what has been accomplished, and what remains to be done. Here we present a set of evidence-based critical event cognitive aids for neuroanesthesia emergencies developed by the Society for Neuroscience in Anesthesiology and Critical Care (SNACC) Education Committee.

Emergency Response in the Ambulatory Surgery Center

As more surgeries are moving out of the hospital setting, effective emergency response in freestanding ambulatory surgery centers requires organized preparedness. Rapid, consistent emergency response can be challenged by their rarity of occurrence, fast-paced environment, and relative lack of resources. Anesthesiologists who practice in these settings must be aware of the differences between the management of an anesthetic emergency in the hospital with virtually unlimited resources and staff, versus an ambulatory surgery center with limited resources and slightly different goal: stabilization and transfer of care. Regular simulation-based training schedules are effective for ambulatory surgery center preparedness for emergency response.

Clinical and pharmacogenetics associated with recovery time from general anesthesia

AIM

Delayed recovery from general anesthesia is a well-known complication that requires predictive tools and approaches. This study aimed to determine significant factors associated with postanesthesia recovery and to develop an algorithm for estimating recovery time from general anesthesia.

MATERIALS & METHODS

The genotypes of patients were determined by SNaPshot or ARMS-qPCR. The algorithm was developed via machine-learning and tested by the worm plot.

RESULTS

Results showed that OPRM1 rs1799971 (p = 0.006) and ABCG2 rs2231142 (p = 0.041) were significantly associated with recovery time. Ten factors after random forest and stepwise selection were associated with recovery time. Ten factors after random forest and stepwise selection were associated with recovery time. Meanwhile, seven factors were associated with delayed recovery.

CONCLUSION

This study demonstrated that both clinical and pharmacogenetic data are significantly associated with recovery from general anesthesia and provide the basis for pre-emptive prediction tools.

Central Disorders of Hypersomnolence, Restless Legs Syndrome, and Surgery With General Anesthesia: Patient Perceptions

Introduction: The importance of obstructive sleep apnea in patients undergoing surgery with general anesthesia is well-defined, but the surgical and anesthetic implications of other sleep disorders are less clear. We sought to evaluate response to surgery with general anesthesia in patients with central disorders of hypersomnolence or restless legs syndrome.

Methods: We surveyed patients on their most recent surgical procedure with general anesthesia, querying about procedure, recovery, and any changes in sleep disorder symptomatology following the procedure.

Results: Forty-five patients with restless legs syndrome and 57 patients with central disorders of hypersomnolence (15 narcolepsy type 2, 1 narcolepsy type 1, 30 idiopathic hypersomnia, 1 Kleine-Levin syndrome, and 10 subjective sleepiness) completed the survey, with response rates of 45.5 and 53.8%, respectively. While patients in both groups were equally likely to report surgical complications and difficulty awakening from anesthesia, hypersomnolent patients were more likely to report worsened sleepiness (40% of the hypersomnolent group vs. 11% of the RLS group, p = 0.001) and worsening of their sleep disorder symptoms (40% of the hypersomnolent group vs. 9% of the RLS group, p = 0.0001).

Conclusion: Patients with sleep disorders other than sleep apnea frequently report surgical or anesthetic complications. Patients with hypersomnolence disorders commonly perceive that their sleep disorder worsened following a procedure; whether this might be related to long term effects of general anesthesia in a particularly vulnerable clinical population requires further study.

The pharmacogenetics of medications used in general anesthesia

General anesthesia is a state of unconsciousness, amnesia, analgesia and akinesia induced by drugs including opioids, hypnotic-sedative agents, muscle relaxants and antiemetics. Clinical and genetic factors are reported to influence the efficacy and side effects of these agents. Based on the evidence, clinical action is needed to improve clinical outcomes. This review summarizes the latest knowledge with regards to the pharmacogenetics of anesthetics and general anesthesia related complications.

Delayed Emergence From Anesthesia: A Simulation Case for Anesthesia Learners

INTRODUCTION

Delayed emergence is failure to regain consciousness following general anesthesia. It commonly involves altered mental status and respiratory compromise leading to increased morbidity, operating room delays, and increased cost. Causes include residual anesthetics, pharmacologic actions, surgical complications, neurologic events, endocrine disturbances, and patient-related factors. Pseudocholinesterase deficiency is an important consideration in delayed emergence. These patients are unable to effectively metabolize the muscle relaxants succinylcholine and mivacurium, leading to prolonged paralysis following administration.

METHODS

This simulation exercise is designed for medical students, student nurse anesthetists, and resident physicians. It is a 1-hour small-group learning activity centered upon a single patient encounter. We employ this exercise using an anesthesiology resident physician to proctor, a simulation technician to program and run, and a faculty anesthesiologist to mentor each session. It is intended to reinforce required reading assignments and improve the approach to delayed emergence from anesthesia. The debriefing includes discussion of risk-reduction strategies for incorporation in clinical practice. This exercise is easily reproduced using modern simulation mannequins without specialized programming.

RESULTS

Learners provided evaluations of their experience participating in the exercise, and resident physicians evaluated their experience proctoring the sessions. Responses were positive, and constructive criticism led to modifications to the exercise after development.

DISCUSSION

We use this exercise as an educational opportunity for medical students rotating clinically in our department. Medical students are paired with resident physicians for scenario development and work with faculty to produce valuable educational activities that benefit the entire department.