Propofol-Based Anesthesia Maintenance and/or Volatile Anesthetics during Intracranial Aneurysm Repair: A Comparative Analysis of Neurological Outcomes.

BACKGROUND: Volatile and intravenous anesthetics have substantial effects on physiological functions, notably influencing neurological function and susceptibility to injury. Despite the importance of the anesthetic approach, data on its relative risks or benefits during surgical clipping or endovascular treatments for unruptured intracranial aneurysms (UIAs) remains scant. We investigated whether using volatile anesthetics alone or in combination with propofol infusion yields superior neurological outcomes following UIA obliteration. METHODS: We retrospectively reviewed 1001 patients who underwent open or endovascular treatment for UIA, of whom 596 had short- and long-term neurological outcome data (modified Rankin Scale) recorded. Multivariable ordinal regression analysis was performed to examine the association between the anesthetic approach and outcomes. RESULTS: Of 1001 patients, 765 received volatile anesthetics alone, while 236 received propofol infusion and volatile anesthetics (combined anesthetic group). Short-term neurological outcome data were available for 619 patients and long-term data for 596. No significant correlation was found between the anesthetic approach and neurologic outcomes, irrespective of the type of procedure (open craniotomy or endovascular treatment). The combined anesthetic group had a higher rate of ICU admission (p < 0.001) and longer ICU and hospital length of stay (LOS, p < 0.001). Similarly, a subgroup analysis revealed longer ICU and hospital LOS (p < 0.0001 and p < 0.001, respectively) in patients who underwent endovascular UIA obliteration under a combined anesthetic approach (n = 678). CONCLUSIONS: The addition of propofol to volatile anesthetics during UIA obliteration does not provide short- or long-term benefits to neurologic outcomes. Compared to volatile anesthetics alone, the combination of propofol and volatile anesthetics may be associated with an increased rate of ICU admission, as well as longer ICU and hospital LOS.

Defining and Addressing Anesthesiology Needs in Simulation-based Medical Education.

Background: This study's primary aim was to determine how training programs use simulation-based medical education (SBME), because SBME is linked to superior clinical performance. Methods: An anonymous 10-question survey was distributed to anesthesiology residency program directors across the United States. The survey aimed to assess where and how SBME takes place, which resources are available, frequency of and barriers to its use, and perceived utility of a dedicated departmental education laboratory. Results: The survey response rate was 30.4% (45/148). SBME typically occurred at shared on-campus laboratories, with residents typically participating in SBME 1 to 4 times per year. Frequently practiced skills included airway management, trauma scenarios, nontechnical skills, and ultrasound techniques (all ≥ 77.8%). Frequently cited logistical barriers to simulation laboratory use included COVID-19 precautions (75.6%), scheduling (57.8%), and lack of trainers (48.9%). Several respondents also acknowledged financial barriers. Most respondents believed a dedicated departmental education laboratory would be a useful or very useful resource (77.8%). Conclusion: SBME is a widely incorporated activity but may be impeded by barriers that our survey helped identify. Barriers can be addressed by departmental education laboratories. We discuss how such laboratories increase capabilities to support structured SBME events and how costs can be offset. Other academic departments may also benefit from establishing such laboratories.

Assessing Interrater Reliability of a Faculty-Provided Feedback Rating Instrument.

High quality feedback on resident clinical performance is pivotal to growth and development. Therefore, a reliable means of assessing faculty feedback is necessary. A feedback assessment instrument would also allow for appropriate focus of interventions to improve faculty feedback. We piloted an assessment of the interrater reliability of a seven-item feedback rating instrument on faculty educators trained via a three-workshop frame-of-reference training regimen. The rating instrument's items assessed for the presence or absence of six feedback traits: actionable, behavior focused, detailed, negative feedback, professionalism / communication, and specific; as well as for overall utility of feedback with regard to devising a resident performance improvement plan on an ordinal scale from 1 to 5. Participants completed three cycles consisting of one-hour-long workshops where an instructor led a review of the feedback rating instrument on deidentified feedback comments, followed by participants independently rating a set of 20 deidentified feedback comments, and the study team reviewing the interrater reliability for each feedback rating category to guide future workshops. Comments came from four different anesthesia residency programs in the United States; each set of feedback comments was balanced with respect to utility scores to promote participants' ability to discriminate between high and low utility comments. On the third and final independent rating exercise, participants achieved moderate or greater interrater reliability on all seven rating categories of a feedback rating instrument using Gwet's agreement coefficient 1 for the six feedback traits and using intraclass correlation for utility score. This illustrates that when this instrument is utilized by trained, expert educators, reliable assessments of faculty-provided feedback can be made. This rating instrument, with further validity evidence, has the potential to help programs reliably assess both the quality and utility of their feedback, as well as the impact of any educational interventions designed to improve feedback.

The Effect of Antiseizure Medication Administration on Mortality and Early Posttraumatic Seizures in Critically Ill Older Adults with Traumatic Brain Injury.

BACKGROUND: Traumatic brain injury (TBI) is a major cause of morbidity and mortality in the United States. Older adults represent an understudied and growing TBI population. Current Brain Trauma Foundation guidelines support prophylactic antiseizure medication (ASM) administration to reduce the risk of early posttraumatic seizures (within 7 days of injury) in patients with severe TBI. Whether ASM decreases mortality or early seizure risk in this population remains unclear. This study addresses the knowledge gap regarding the impact of ASM administration on the risk of seizure or mortality after TBI in patients more than 65 years of age. METHODS: This retrospective cohort study used a publicly available data set from the Medical Information Mart for Intensive Care-III from the Massachusetts Institute of Technology. Our cohort included patients 65 years or older with a primary exposure of early ASM administration with TBI resulting in an intensive care unit (ICU) admission in a level I trauma center from 2001 to 2012. A double-robust inverse propensity scale weighted model on the basis of proportional hazard and logistic regression models was created to assess the association between ASM administration and risk of death within 7 days of admission to the ICU. Secondary outcomes included 30-day mortality and 1-year mortality, early posttraumatic seizures, ICU length of stay, and hospital length of stay. RESULTS: Of 1145 patients 65 years or older with TBI admitted to an ICU, 783 (68.4%) received ASM within the first 24 h. Patients meeting inclusion criteria were predominantly white (83.8%) and were male (52.3%), with a median (interquartile range) age of 81 (74-86) years. TBI severity, classified by Glasgow Coma Score, was predominantly mild (71.2%), followed by moderate (16.8%) and severe (11.3%). Patients who received ASM were less likely to have died at 7 days (adjusted death hazard ratio [HR] = 0.48 [95% confidence interval {CI} 0.28-0.88], P = 0.005), at 30 days (adjusted HR 0.67 [95% CI 0.45-0.99], P = 0.045), and at 1 year (adjusted HR 0.72 [95% CI 0.54-0.97], P = 0.029). Groups were not different in regard to seizure (adjusted seizure odds ratio 1.18 [95% CI 0.61-2.26]) compared with those who did not receive ASM. CONCLUSIONS: Early ASM administration was associated with reduced mortality at 7 days, 30 days, and 1 year but did not decrease the risk of early seizures among older adults who presented with TBI at an ICU. This benefit was observed in mild, moderate, and severe TBI assessed by Glasgow Coma Score on presentation among patients 65 years old and older and suggests broader recommendations for the use of ASM in older adults who present with TBI of any severity at an ICU.

Perception of Web-Based Didactic Activities During the COVID-19 Pandemic Among Anesthesia Residents: Pilot Questionnaire Study.

BACKGROUND: Physical and social distancing recommendations aimed at limiting exposure during the COVID-19 pandemic have forced residency programs to increasingly rely on videoconferencing and web-based resources. OBJECTIVE: In this pilot study, we aimed to explore the effects of the COVID-19 pandemic on residency training experience, and to delineate the perceived barriers to the successful implementation of web-based medical education. METHODS: A 19-item survey was compiled and distributed electronically using Qualtrics. This anonymous survey included information on the training level of each resident, their participation in formal didactics before and during the pandemic, and their perception of the ease and limitations of virtual didactics. The resident's opinions on specific educational resources were assessed, and the effectiveness of new delivery methods on resident engagement and learning was examined. RESULTS: Thirty anesthesiology residents were surveyed, 19 of whom agreed to participate in the pilot study. One participant with incomplete responses was excluded, yielding a final cohort of 18 respondents. Most residents (56%, 10/18) reported that the COVID-19 pandemic negatively affected their residency training. The time spent on didactic training and independent studies was, nevertheless, not affected by the pandemic for 90% (16/18) of respondents. Nonetheless, 72% (13/18) of residents were less engaged during virtual lectures in comparison to in-person didactics. Important limitations included distraction from the physical environment (67%, 12/18), internet instability (67%, 12/18), less obligation to participate (44%, 8/18), technical difficulty and unmuted microphones (33%, 6/18, each), and people speaking over each other (28%, 5/18). Despite these limitations, most residents stated that they would like to keep a combination of virtual didactics including live Zoom lectures (56%, 10/18), prerecorded web didactics (56%, 10/18), and virtual ground rounds via Zoom (50%, 9/18) as the "new normal." CONCLUSIONS: Despite important limitations listed in this report, anesthesia residents would like to keep a combination of virtual lectures and presentations as the new normal after the COVID-19 pandemic.

Risk Factors for Delayed Extubation Following High Posterior Cervical and Occipital Fusion.

BACKGROUND: Much has been written on initial airway management in patients undergoing cervical spine procedures, but comparatively less is known about extubation criteria. High cervical and occipital fusion procedures pose a particular risk for extubation given the potential for a reduced range of motion at the occiput-C1 and C1-C2 joints should reintubation be necessary. MATERIALS AND METHODS: We performed a retrospective cohort analysis of posterior high cervical and occipital fusion cases to identify factors related to delayed extubation and postoperative airway and pulmonary complications. Using a convenience sample of all cases operated between January 2009 and April 2018, we reviewed anesthesia records and discharge summaries to compare patient characteristics, airway management, surgical factors, and postoperative complications between patients who underwent delayed extubation and those who did not. RESULTS: A total of 135 patients met our inclusion criteria. Overall, 92 (68.1%) patients were extubated in the operating room (OR), and 43 (31.9%) underwent delayed extubation. Multivariate logistic regression analysis identified age, procedure length, C2 as the highest level fused, and percentage colloid administered as predictors of delayed extubation. We did not find a difference in the rate of postoperative pulmonary complications between groups (6/92 [6.5%] for OR extubation; 2/43 [4.7%] for delayed extubation). Two patients had serious airway complications, and both were extubated in the OR (2/92, 2.2%). CONCLUSIONS: The decision to extubate immediately postoperatively after high cervical and occipital fusion should be considered carefully as the morbidity associated with airway obstruction can be severe in this population, while negative effects of delayed extubation were not evident in our analysis.

Teaching Medical Students to Create Anesthetic Plans Using a Branched-Chain Learning Module.

It is challenging to include medical students in the anesthetic decision-making process during their introductory clinical rotation in anesthesiology. Furthermore, the rotation is often too brief to even expose students to the variety inherent in anesthesia practice. We created a web-based, branched-chain learning module (BCLM) for medical students with alternate narratives and patient outcomes based on their anesthetic choices. In semistructured group interviews, students described how the BCLM met its educational objectives and gave constructive feedback on several ways to improve their experience with it, guiding the future use of BCLMs in medical education.

Anesthetic management of unruptured intracranial aneurysms: a qualitative systematic review.

Intracranial aneurysms (IA) occur in 3-5% of the general population and may require surgical or endovascular obliteration if the patient is symptomatic or has an increased risk of rupture. These procedures carry an inherent risk of neurological complications, and the outcome can be influenced by the physiological and pharmacological effects of the administered anesthetics. Despite the critical role of anesthetic agents, however, there are no current studies to systematically assess the intraoperative anesthetic risks, benefits, and outcome effects in this population. In this systematic review of the literature, we carefully examine the existing evidence on the risks and benefits of common anesthetic agents during IA obliteration, their physiological and clinical characteristics, and effects on neurological outcome. The initial search strategy captured a total of 287 published studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 28 studies were included in the final report. Our data showed that both volatile and intravenous anesthetics are commonly employed, without evidence that either is superior. Although no specific anesthetic regimens are promoted, their unique neurological, cardiovascular, and physiological properties may be critical to the outcome in vulnerable patients. In particular, patients at risk for perioperative ischemia may benefit from timely administration of anesthetic agents with neuroprotective properties and optimization of their physiological parameters. Further studies are warranted to examine if these anesthetic regimens can reduce the risk of neurological injury and improve the overall outcome in these patients.

Neurophysiologic Intraoperative Monitoring for Spine Surgery: A Practical Guide From Past to Present.

Intraoperative neuromonitoring was introduced in the second half of the 20th century with the goal of preventing patient morbidity for patients undergoing complex operations of the central and peripheral nervous system. Since its early use for scoliosis surgery, the growth and utilization of IOM techniques expanded dramatically over the past 50 years to include spinal tumor resection and evaluation of cerebral ischemia. The importance of IOM has been broadly acknowledged, and in 1989, the American Academy of Neurology (AAN) released a statement that the use of SSEPs should be standard-of-care during spine surgery. In 2012, both the AAN and the American Clinical Neurophysiology Society (ACNS) recommended that: "Intraoperative monitoring (IOM) using SSEPs and transcranial MEPs be established as an effective means of predicting an increased risk of adverse outcomes, such as paraparesis, paraplegia, and quadriplegia, in spinal surgery." With a multimodal approach that combines SSEPs, MEPs, and sEMG with tEMG and D waves, as appropriate, sensitivity and specificity can be maximized for the diagnosis of reversible insults to the spinal cord, nerve roots, and peripheral nerves. As with most patient safety efforts in the operating room, IOM requires contributions from and communication between a number of different teams. This comprehensive review of neuromonitoring techniques for surgery on the central and peripheral nervous system will highlight the technical, surgical and anesthesia factors required to optimize outcomes. In addition, this review will discuss important trouble shooting measures to be considered when managing ION changes concerning for potential injury.

More Even Distribution of ACGME-mandated Cases Improves Residents' Perceptions of Fairness and Balance.

BACKGROUND: The Accreditation Council for Graduate Medical Education (ACGME) mandates minimum numbers of cases in many specialties, including anesthesiology, but resident scheduling is often done on the basis of time spent on each rotation rather the number of opportunities for specific cases, risking uneven case distribution, particularly for low-volume cases. We used the neuroanesthesia rotation as a model to evaluate a system to more evenly distribute ACGME-mandated cases among residents and assessed the effects on their perceptions of their experience on the rotation. METHODS: In November 2018, we instituted a targeted operating room scheduling system at our institution by making specific daily assignment requests for anesthesia residents on the neuroanesthesia rotation. We used Shewhart control charts to analyze the variation in case distribution among all resident rotations (N = 91) from January 2018 to October 2019. We then surveyed residents who had experienced both systems (n = 15) and those who had experienced only the old system (n = 16). RESULTS: Shewhart p-charts of the proportion of ACGME-mandated cases assigned to each resident showed wide variation under the old scheduling system and a more even distribution under the new system. Residents reported significantly greater perceived fairness of case distribution and balance between their education and service obligations under the new system (response rates: 10/16 [62.5%] and 13/15 [86.7%]). CONCLUSIONS: Targeted resident scheduling based on ACGME-mandated case numbers rather than solely time spent on a rotation is feasible and can improve resident perceptions of fairness and balance between education and service, a top priority of the ACGME.

Phosphorylation of Complexin by PKA Regulates Activity-Dependent Spontaneous Neurotransmitter Release and Structural Synaptic Plasticity.

Synaptic plasticity is a fundamental feature of the nervous system that allows adaptation to changing behavioral environments. Most studies of synaptic plasticity have examined the regulated trafficking of postsynaptic glutamate receptors that generates alterations in synaptic transmission. Whether and how changes in the presynaptic release machinery contribute to neuronal plasticity is less clear. The SNARE complex mediates neurotransmitter release in response to presynaptic Ca(2+) entry. Here we show that the SNARE fusion clamp Complexin undergoes activity-dependent phosphorylation that alters the basic properties of neurotransmission in Drosophila. Retrograde signaling following stimulation activates PKA-dependent phosphorylation of the Complexin C terminus that selectively and transiently enhances spontaneous release. Enhanced spontaneous release is required for activity-dependent synaptic growth. These data indicate that SNARE-dependent fusion mechanisms can be regulated in an activity-dependent manner and highlight the key role of spontaneous neurotransmitter release as a mediator of functional and structural plasticity.

Differential regulation of evoked and spontaneous neurotransmitter release by C-terminal modifications of complexin.

Complexins are small α-helical proteins that modulate neurotransmitter release by binding to SNARE complexes during synaptic vesicle exocytosis. They have been found to function as fusion clamps to inhibit spontaneous synaptic vesicle fusion in the absence of Ca(2+), while also promoting evoked neurotransmitter release following an action potential. Complexins consist of an N-terminal domain and an accessory α-helix that regulates the activating and inhibitory properties of the protein, respectively, and a central α-helix that binds the SNARE complex and is essential for both functions. In addition, complexins contain a largely unstructured C-terminal domain whose role in synaptic vesicle cycling is poorly defined. Here, we demonstrate that the C-terminus of Drosophila complexin (DmCpx) regulates localization to synapses and that alternative splicing of the C-terminus can differentially regulate spontaneous and evoked neurotransmitter release. Characterization of the single DmCpx gene by mRNA analysis revealed expression of two alternatively expressed isoforms, DmCpx7A and DmCpx7B, which encode proteins with different C-termini that contain or lack a membrane tethering prenylation domain. The predominant isoform, DmCpx7A, is further modified by RNA editing within this C-terminal region. Functional analysis of the splice isoforms showed that both are similarly localized to synaptic boutons at larval neuromuscular junctions, but have differential effects on the regulation of evoked and spontaneous fusion. These data indicate that the C-terminus of Drosophila complexin regulates both spontaneous and evoked release through separate mechanisms and that alternative splicing generates isoforms with distinct effects on the two major modes of synaptic vesicle fusion at synapses.

A presynaptic endosomal trafficking pathway controls synaptic growth signaling.

Structural remodeling of synapses in response to growth signals leads to long-lasting alterations in neuronal function in many systems. Synaptic growth factor receptors alter their signaling properties during transit through the endocytic pathway, but the mechanisms controlling cargo traffic between endocytic compartments remain unclear. Nwk (Nervous Wreck) is a presynaptic F-BAR/SH3 protein that regulates synaptic growth signaling in Drosophila melanogaster. In this paper, we show that Nwk acts through a physical interaction with sorting nexin 16 (SNX16). SNX16 promotes synaptic growth signaling by activated bone morphogenic protein receptors, and live imaging in neurons reveals that SNX16-positive early endosomes undergo transient interactions with Nwk-containing recycling endosomes. We identify an alternative signal termination pathway in the absence of Snx16 that is controlled by endosomal sorting complex required for transport (ESCRT)-mediated internalization of receptors into the endosomal lumen. Our results define a presynaptic trafficking pathway mediated by SNX16, NWK, and the ESCRT complex that functions to control synaptic growth signaling at the interface between endosomal compartments.

Altered gene regulation and synaptic morphology in Drosophila learning and memory mutants.

Genetic studies in Drosophila have revealed two separable long-term memory pathways defined as anesthesia-resistant memory (ARM) and long-lasting long-term memory (LLTM). ARM is disrupted in radish (rsh) mutants, whereas LLTM requires CREB-dependent protein synthesis. Although the downstream effectors of ARM and LLTM are distinct, pathways leading to these forms of memory may share the cAMP cascade critical for associative learning. Dunce, which encodes a cAMP-specific phosphodiesterase, and rutabaga, which encodes an adenylyl cyclase, both disrupt short-term memory. Amnesiac encodes a pituitary adenylyl cyclase-activating peptide homolog and is required for middle-term memory. Here, we demonstrate that the Radish protein localizes to the cytoplasm and nucleus and is a PKA phosphorylation target in vitro. To characterize how these plasticity pathways may manifest at the synaptic level, we assayed synaptic connectivity and performed an expression analysis to detect altered transcriptional networks in rutabaga, dunce, amnesiac, and radish mutants. All four mutants disrupt specific aspects of synaptic connectivity at larval neuromuscular junctions (NMJs). Genome-wide DNA microarray analysis revealed ∼375 transcripts that are altered in these mutants, suggesting defects in multiple neuronal signaling pathways. In particular, the transcriptional target Lapsyn, which encodes a leucine-rich repeat cell adhesion protein, localizes to synapses and regulates synaptic growth. This analysis provides insights into the Radish-dependent ARM pathway and novel transcriptional targets that may contribute to memory processing in Drosophila.