Artificial Intelligence for Anesthesiology Board-Style Examination Questions: Role of Large Language Models

New artificial intelligence tools have been developed that have implications for medical usage. Large language models (LLMs), such as the widely used ChatGPT developed by OpenAI, have not been explored in the context of anesthesiology education. Understanding the reliability of various publicly available LLMs for medical specialties could offer insight into their understanding of the physiology, pharmacology, and practical applications of anesthesiology. An exploratory prospective review was conducted using 3 commercially available LLMs--OpenAI's ChatGPT GPT-3.5 version (GPT-3.5), OpenAI's ChatGPT GPT-4 (GPT-4), and Google's Bard--on questions from a widely used anesthesia board examination review book. Of the 884 eligible questions, the overall correct answer rates were 47.9% for GPT-3.5, 69.4% for GPT-4, and 45.2% for Bard. GPT-4 exhibited significantly higher performance than both GPT-3.5 and Bard (p = 0.001 and p < 0.001, respectively). None of the LLMs met the criteria required to secure American Board of Anesthesiology certification, according to the 70% passing score approximation. GPT-4 significantly outperformed GPT-3.5 and Bard in terms of overall performance, but lacked consistency in providing explanations that aligned with scientific and medical consensus. Although GPT-4 shows promise, current LLMs are not sufficiently advanced to answer anesthesiology board examination questions with passing success. Further iterations and domain-specific training may enhance their utility in medical education.

Misidentification of the True Aortic Annulus With 2-dimensional Echocardiography: A Critical Appraisal Using 3-Dimensional Imaging

OBJECTIVES

This study aimed to evaluate the accuracy of identifying the true aortic valve (AV) annulus using 2-dimensional (2D) echocardiography, with the goal of highlighting potential misidentification issues in clinical practice.

DESIGN

An observational study employing 3-dimensional (3D) datasets to generate 2D images of the AV annulus for analysis.

SETTING

The study was conducted in an academic medical center.

PARTICIPANTS

Three-dimensional transesophageal echocardiography datasets were obtained from 11 patients with normal AV and aortic root anatomies undergoing coronary artery bypass surgery. Attending anesthesiologists certified by the National Board of Echocardiography (NBE) were approached subsequently to participate in this study.

INTERVENTIONS

Two images per patient were generated from 3D datasets, reflecting the mid-esophageal long-axis view of the AV, a true AV annulus image, and an off-axis image. A survey was distributed to NBE-certified perioperative echocardiographers across 12 academic institutions to identify the true AV annulus from these images.

MEASUREMENTS AND MAIN RESULTS

The survey, completed by 45 qualified respondents, revealed a significant misidentification rate of the true AV annulus, with only 36.8% of responses correctly identifying it. The rate of correct identification varied across image sets, with 44.4% of participants unable to correctly identify any true AV annulus image.

CONCLUSIONS

The study highlighted the limitations of 2D echocardiography in accurately identifying the true AV annulus in complex 3D structures like the aortic root. The findings suggest a need for greater reliance on advanced imaging modalities, such as 3D echocardiography, to improve accuracy in clinical practice.

A Multidisciplinary Protocolized Approach for Ruptured Abdominal Aortic Aneurysm Management: A Retrospective Before-After Study

OBJECTIVES

To investigate whether implementation of a multidisciplinary protocol for ruptured abdominal aortic aneurysm (rAAA) management reduces rates of adverse complications.

DESIGN

A retrospective before-after study.

SETTING

A tertiary-care academic hospital.

PARTICIPANTS

Adult patients who underwent open or endovascular rAAA repair; data were stratified into before-protocol implementation (group 1: 2015-2018) and after-protocol implementation (group 2: 2019-2022) groups.

INTERVENTION

The protocol details the workflow for vascular surgery, anesthesia, emergency department, and operating room staff for a rAAA case; training was accomplished through yearly workshops.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was in-hospital mortality. Secondary outcomes included all-cause morbidity and other major complications. Differences in postoperative complication rates between groups were assessed using Pearson's χ2 test. Of the 77 patients included undergoing rAAA repair, 41 (53.2%) patients were in group 1, and 36 (46.8%) patients were in group 2. Patients in group 2 had a significantly shorter median time to incision (1.0 v 0.7 hours, p = 0.022) and total procedure time (180.0 v 160.5 minutes, p = 0.039) for both endovascular and open repair. After protocol implementation, patients undergoing endovascular repair exhibited significantly lower rates of mortality (46.2% v 20.0%, p = 0.048), all-cause morbidity (65.4% v 44.0%, p = 0.050), and renal complications (15.4% v 0.0%, p = 0.036); patients undergoing open repair for a rAAA exhibited significantly lower rates of mortality (53.3% v 27.3%, p = 0.018) and bowel ischemia (26.7% v 0.0%, p = 0.035).

CONCLUSIONS

Implementation of a multidisciplinary protocol for the management of a rAAA may reduce rates of adverse complications and improve the quality of care.

Virtual Reality: The Future of Invasive Procedure Training?

Invasive procedures are associated with adverse events that are both hazardous to patients and expensive to treat. A trainee is expected to perform complex sterile invasive procedures in a dynamic environment under time pressure while maintaining patient safety at the highest standard of care. For mastery in performing an invasive procedure, the automatism of the technical aspects is required, as well as the ability to adapt to patient conditions, anatomic variability, and environmental stressors. Virtual reality (VR) simulation training is an immersive technology with immense potential for medical training, potentially enhancing clinical proficiency and improving patient safety. Virtual reality can project near-realistic environments onto a head-mounted display, allowing users to simulate and interact with various scenarios. Virtual reality has been used extensively for task training in various healthcare-related disciplines and other fields, such as the military. These scenarios often incorporate haptic feedback for the simulation of physical touch and audio and visual stimuli. In this manuscript, the authors have presented a historical review, the current status, and the potential application of VR simulation training for invasive procedures. They specifically explore a VR training module for central venous access as a prototype for invasive procedure training to describe the advantages and limitations of this evolving technology.

Evaluation of Technical Performance of Ultrasound-Guided Procedures through Hand Motion Analysis: an Exploration of Motion Metrics

PURPOSE

To evaluate the ability of hand motion analysis using conventional and new motion metrics to differentiate between operators of varying levels of experience for central venous access (CVA) and liver biopsy (LB).

METHODS

CVA task: 7 Interventional Radiologists (experts), 10 senior trainees, and 5 junior trainees performed ultrasound-guided CVA on a standardized manikin; 5 trainees were retested after one year. LB task: 4 Radiologists (experts) and 7 trainees biopsied a lesion on a manikin. Conventional motion metrics (path length and task time), a refined metric (translational movements), and new metrics (rotational sum, rotational movements), were calculated.

RESULTS

CVA: experts outperformed trainees on all metrics (p ≤ 0.02). Senior trainees required fewer rotational movements (p = 0.02), translational movements (p = 0.045), and time (p = 0.001) than junior trainees. Similarly, on one-year follow-up, trainees had fewer translational (p=0.02) and rotational movements (p=0.003) with less task time (p=0.003). Path length and rotational sum were not different between junior and senior trainees or for trainees on follow-up. Rotational and translational movement had a greater area-under-the-curve (0.91 and 0.86 respectively) compared to rotational sum (0.73) and path length (0.61). LB: experts performed the task with a shorter path length (p=0.04), fewer translational movements (p=0.04), rotational movements (p=0.02), and less time (p<0.001) relative to the trainees.

CONCLUSION

Hand motion analysis using translational and rotational movements was better at differentiating levels of experience and improvement with training, as compared to the conventional metric of path length.

Novel Three-Dimensionally Printed Ultrasound Probe Simulator and Heart Model for Transthoracic Echocardiography Education

Simulation-based training is an essential component in the education of transthoracic echocardiography (TTE). Nevertheless, current TTE teaching methods may be subject to certain limitations. Hence, the authors in this study aimed to invent a novel TTE training system employing three-dimensional (3D) printing technology to teach the basic principles and psychomotor skills of TTE imaging more intuitively and understandably. This training system comprises a 3D-printed ultrasound probe simulator and a sliceable heart model. The probe simulator incorporates a linear laser generator to enable the visualization of the projection of the ultrasound scan plane in a 3D space. By using the probe simulator in conjunction with the sliceable heart model or other commercially available anatomic models, trainees can attain a more comprehensive understanding of probe motion and related scan planes in TTE. Notably, the 3D-printed models are portable and low-cost, suggesting their potential utility in various clinical scenarios, particularly for just-in-time training.

Structural and Electrical Integrity of Transesophageal Echocardiography Probes: Importance and Key Concepts

The clinical utility of transesophageal echocardiography (TEE) is well-established for patients undergoing cardiac surgery. With the increase in percutaneous structural heart disease procedures that rely on TEE for procedural guidance, the use of TEE probes is expanding. Although there are well-established protocols for routine cleaning and decontaminating TEE probes between patient use, there is a lack of awareness and misconceptions about maintaining TEE probes' structural and electrical integrity. The electrical leakage test (ELT) is routinely performed between patient use. From a patient safety standpoint, the ELT is necessary to ensure the longevity of this expensive equipment and prevent disruptions to the workflow in a busy department caused by TEE probes being decommissioned due to probe damage. This technical communication aims to highlight the importance of maintaining TEE probes' structural and electrical integrity. The article also highlights and discusses probe handling techniques between patient use, emphasizing the ELT to ensure patient safety and compliance with national and international standards.

Motion Analysis: An Objective Assessment of Special Operations Forces and Tactical Medics Performing Point-of-Care Ultrasound

BACKGROUND

Point-of-care ultrasound (POCUS) is commonly employed to image the heart, lungs, and abdomen. Rapid ultrasound for shock and hypotension (RUSH) exams are a critical component of POCUS employed in austere environments by Special Operations Forces (SOF) and tactical medics for triage and diagnosis. Despite its utility, training for POCUS remains largely unstandardized with respect to feedback and markers of proficiency. We hypothesized that motion analysis could objectively identify improvement in medics' performance of RUSH exams. Furthermore, we predicted that motion metrics would correlate with qualitative ratings administered by attending anesthesiologists.

METHODS

A team of civilian and military attending anesthesiologists trained 24 medics in POCUS during a 5-day course. Each medic performed eight RUSH exams using an ultrasound probe equipped with an electromagnetic motion sensor to track total distance travelled (path length), movements performed (translational motions), degrees rotated (rotational sum), and time. Instructors (experts) observed and rated the exams on the following items: image finding, image fine-tuning, speed, final image accuracy, and global assessment. Motion metrics were used to provide feedback to medics throughout the course. Generalized estimating equations were used to analyze the trends of motion metrics across all trials. Correlations amongst motion metrics and expert ratings were assessed with Pearson correlation coefficients.

RESULTS

Participants exhibited a negative trend in all motion metrics (p < 0.001). Pearson correlation coefficients revealed moderate inverse correlations amongst motion metrics and expert ratings.

CONCLUSION

Motion analysis was able to quantify and describe the performance of medics training in POCUS and correlated with expert ratings.

Regulation of Hypoxic-Adenosinergic Signaling by Estrogen: Implications for Microvascular Injury

Loss of estrogen, as occurs with normal aging, leads to increased inflammation, pathologic angiogenesis, impaired mitochondrial function, and microvascular disease. While the influence of estrogens on purinergic pathways is largely unknown, extracellular adenosine, generated at high levels by CD39 and CD73, is known to be anti-inflammatory in the vasculature. To further define the cellular mechanisms necessary for vascular protection, we investigated how estrogen modulates hypoxic-adenosinergic vascular signaling responses and angiogenesis. Expression of estrogen receptors, purinergic mediators inclusive of adenosine, adenosine deaminase (ADA), and ATP were measured in human endothelial cells. Standard tube formation and wound healing assays were performed to assess angiogenesis in vitro. The impacts on purinergic responses in vivo were modeled using cardiac tissue from ovariectomized mice. CD39 and estrogen receptor alpha (ERα) levels were markedly increased in presence of estradiol (E2). Suppression of ERα resulted in decreased CD39 expression. Expression of ENT1 was decreased in an ER-dependent manner. Extracellular ATP and ADA activity levels decreased following E2 exposure while levels of adenosine increased. Phosphorylation of ERK1/2 increased following E2 treatment and was attenuated by blocking adenosine receptor (AR) and ER activity. Estradiol boosted angiogenesis, while inhibition of estrogen decreased tube formation in vitro. Expression of CD39 and phospho-ERK1/2 decreased in cardiac tissues from ovariectomized mice, whereas ENT1 expression increased with expected decreases in blood adenosine levels. Estradiol-induced upregulation of CD39 substantially increases adenosine availability, while augmenting vascular protective signaling responses. Control of CD39 by ERα follows on transcriptional regulation. These data suggest novel therapeutic avenues to explore in the amelioration of post-menopausal cardiovascular disease, by modulation of adenosinergic mechanisms.

Timing of Blood Transfusions and 30-Day Patient Outcomes After Coronary Artery Bypass Graft Surgery

OBJECTIVE

Packed red blood cell transfusion during coronary artery bypass graft surgery is known to be associated with adverse outcomes. However, the association of the timing between transfusions in relation to discharge and 30-day postoperative outcomes has not been studied. The study authors investigated the impact of transfusion timing on 30-day surgical outcomes.

DESIGN

A retrospective review.

SETTING

At a single tertiary-care academic hospital.

PARTICIPANTS

A total of 2,481 adult patients underwent primary coronary artery bypass graft surgery between January 2014 and December 2020.

MEASUREMENTS AND MAIN RESULTS

The relationship between the timing of packed red blood cell transfusion (intraoperative, postoperative, or both) and 30-day postoperative outcome variables was calculated as an odds ratio. The influence of timing of transfusion on adjusted probability of postoperative complications was plotted against the lowest intraoperative hematocrit. The median age of the population was 67 years (60.0-74.0), body mass index was 28.5 (25.6-32.3) kg/m², and 497 (20.0%) were female. A total of 1,588 (36%) patients received packed red blood cell transfusions; 182 (7.3%) received intraoperative transfusions, 489 (19.7%) received postoperative transfusions, and 222 (9.0%) received both (intraoperative and postoperative transfusions). Postoperative transfusion was associated with significantly higher odds of readmission (1.83 [1.32-2.54], p = 0.002) and heart failure (1.64 [1.2-2.23], p = 0.008) compared to patients with no transfusions; whereas intraoperative transfusions were not.

CONCLUSION

The authors' data suggested that the postoperative timing of transfusion in patients undergoing coronary artery bypass graft surgery may be associated with an increased incidence of 30-day heart failure and readmission. Prospective research is needed to conclusively confirm these findings.

Novel Three-Dimensional Printed Human Heart Models and Ultrasound Omniplane Simulator for Transesophageal Echocardiography Training

Simulation-based training plays an essential role in transesophageal echocardiography (TEE) education. Using 3-dimensional printing technology, the authors invented a novel TEE teaching system consisting of a series of heart models that can be segmented according to actual TEE views, and an ultrasound omniplane simulator to demonstrate how ultrasound beams intersect the heart at different angles and generate images. This novel teaching system is able to provide a more direct way to visualize the mechanics of obtaining TEE images than traditional online or mannequin-based simulators. It can also provide tangible feedback of both an ultrasound scan plane and a TEE view of the heart, which has been proven to improve trainees' spatial awareness and can significantly help in understanding and memorizing complex anatomic structures. This teaching system itself is also portable and inexpensive, making it conducive to teaching TEE in regions of diverse economic status. This teaching system also can be expected to be used for just-in-time training in a variety of clinical scenarios, including operating rooms, intensive care units, etc.

Abstract WP180: Gender-specific Risk Of Stroke In Patients With Peripheral Artery Disease

Objective: Peripheral artery disease (PAD) is a common atherosclerotic disease associated with increased morbidity and mortality. We conducted a retrospective review to investigate the role of gender in influencing the incidence of stroke after surgery for PAD.

Methods: We conducted a retrospective review using data from the Vascular Quality Initiative database for patients who underwent supra-inguinal and infra-inguinal surgery between 2010 and 2020. The relationship between gender and 30-day post-operative outcomes was calculated as an odds ratio; the threshold of significance was p =0.05 for univariate and multivariable analysis. Gender-based influence of age and adjusted probability of stroke was plotted using Sigma Plot.

Results: A total of 79,981 patients were included based on our eligibility criteria, 34% of which were female. Although only 0.6% of patients experienced stroke, risk of stroke was significantly higher in female patients ( p <0.001). Female patients were more commonly hypertensive ( p =0.007) and diabetic ( p =0.003), while also presenting decreased pre-operative use of statin ( p <0.001) and aspirin ( p <0.001) as compared to males. Additional predictors of post-operative stroke include age > 65 years ( p =0.015), hypertension ( p =0.002), and pre-operative use of beta blockers ( p <0.001). Overall, females had higher risk of all-cause morbidity ( p =0.004), stroke ( p <0.001), mortality ( p <0.001), and major adverse cardiovascular events ( p <0.001), while males had increased risk of returning to the operating room ( p =0.006). Regression analysis revealed a significantly stronger bearing of high age on probability of post-operative stroke in women ( p <0.001).

Conclusion: Our data suggests that incidence of post-operative stroke and other cardiovascular complications is influenced by gender in surgery of PAD. Future research investigating underlying gender-based mechanisms is necessary to personalize treatment in patients with PAD.

National Delphi Survey on Anesthesiology Resident Training in Perioperative Ultrasound

OBJECTIVE

To establish agreement among nationwide experts through a Delphi process on the key components of perioperative ultrasound and the recommended minimum number of examinations that should be performed by a resident upon graduation.

DESIGN

A prospective cross-sectional study.

SETTING

A survey on multiinstitutional academic medical centers.

PARTICIPANTS

Anesthesiology residency program directors and/or experts in perioperative ultrasound.

INTERVENTIONS

A list of components and examinations recommended for anesthesiology resident training in perioperative ultrasound was developed based on guidelines and 2 survey rounds among a steering committee of 10 experts. A questionnaire asking for a rating of each component on a 5-point Likert scale subsequently was sent to an expert panel of 120 anesthesiology residency program directors across the United States. An agreement of at least 70% of participants, rating a component as 4 or 5, was compulsory to list a component as essential for anesthesiology resident training in perioperative ultrasound.

MEASUREMENTS AND MAIN RESULTS

The nationwide survey's response rate was 62.5%, and agreement was reached after 2 Delphi rounds. The final list included 44 essential components for basic ultrasound physics and knobology, cardiac ultrasound, lung ultrasound, and ultrasound-guided vascular access. Agreement was not reached for abdominal ultrasound, gastric ultrasound, and ultrasound-guided airway assessment. Agreement for the recommended minimum number of examinations that should be performed by a resident upon graduation included 50 each for transthoracic and transesophageal echocardiography, and 20 each for lung ultrasound, ultrasound-guided central line, and ultrasound-guided arterial line placements.

CONCLUSIONS

The recommendations outlined in this survey can be used to establish standardized training for perioperative ultrasound by anesthesiology residency programs.

A Systematic Review and Meta-analysis of General versus Regional Anesthesia for Lower Extremity Amputation

OBJECTIVE

Postoperative morbidity in patients undergoing lower extremity amputation (LEA) has remained high. Studies investigating the influence of the anesthetic modality on the postoperative outcomes have yielded conflicting results. The aim of our study was to assess the effects of regional anesthesia vs general anesthesia on postoperative complications for patients undergoing LEA.

METHODS

We systematically searched PubMed, Embase, MEDLINE, Web of Science, and Google Scholar from 1990 to 2022 for studies investigating the effect of the anesthetic modality on the postoperative outcomes after LEA. Regional anesthesia (RA) included neuraxial anesthesia and peripheral nerve blocks. The outcomes included 30-day mortality, respiratory failure (unplanned postoperative intubation, failure to wean, mechanical ventilation >24 hours), surgical site infection, cardiac complications, urinary tract infection, renal failure, sepsis, venous thrombosis, pneumonia, and myocardial infarction.

RESULTS

Of the 25 studies identified, we included 10 retrospective observational studies with 81,736 patients, of whom 69,754 (85.3%) had received general anesthesia (GA) and 11,980 (14.7%) had received RA. In the GA group, 50,468 patients were men (63.8%), and in the RA group, 7813 patients were men (62.3%). The results of the meta-analyses revealed that GA was associated with a higher rate of respiratory failure (odds ratio, 1.38; 95% confidence interval, 1.06-1.80; P = .02) and sepsis (odds ratio, 1.21; 95% confidence interval, 1.11-1.33; P < .0001) compared with RA. No differences were found in postoperative 30-day mortality, surgical site infection, cardiac complications, urinary tract infection, renal failure, venous thrombosis, pneumonia, and myocardial infarction between the GA and RA groups.

CONCLUSIONS

The results of our meta-analysis have shown that GA could be associated with a higher rate of respiratory failure and sepsis compared with RA for LEA.

Influence of Increasing Age and Body Mass Index of Gender in COVID-19 Patients

Background: The impact of gender on outcomes in patients suffering from coronavirus disease 2019 (COVID-19) is frequently debated. However, the synchronous influence of additional risk factors is seldom mentioned. With increasing emphasis on identifying patients who are at risk of complications from COVID-19, we decided to conduct a retrospective review to assess the influence of age and body mass index (BMI) on gender-based differences in outcomes. Materials and Methods: A retrospective review of 1288 patients was conducted at a tertiary care hospital. Binary logistic regression was used to assess differences in risk factors and outcomes between genders. The associations between predictors and outcomes were described using odds ratios in tables, forest plots, and regression curves plotted using Sigma Plot. Results: Majority of patients were women (53.6% vs. 46.4%). Median BMI in men was higher than women (p = 0.003). Key predictors for all-cause morbidity/mortality in men were diabetes, chronic kidney disease, and regular use of angiotensin-converting enzyme inhibitors. In women, age >65 and regular use of inhaled steroid were additional risk factors. Men had a higher risk of acute respiratory distress syndrome (2.83 [1.70-4.70]), acute renal failure (1.96 [1.20-3.20]), and had a longer length of stay (0.11 [1.52]). Obesity has a stronger bearing on outcomes in women, and age has a more pronounced effect on outcomes in men. Conclusion: Extremes of BMI and older age are associated with worse outcomes in both men and women. Obesity has a stronger bearing on outcomes of COVID-19 infection in women, while the effect of older age on outcomes is more pronounced in men.

Comprehensive Ultrasound Course for Special Operations Combat and Tactical Medics

BACKGROUND

Advances in ultrasound technology with enhanced portability and high-quality imaging has led to a surge in its use on the battlefield by nonphysician providers. However, there is a consistent need for comprehensive and standardized ultrasound training to improve ultrasound knowledge, manual skills, and workflow understanding of nonphysician providers.

MATERIALS AND METHODS

Our team designed a multimodal ultrasound course to improve ultrasound knowledge, manual skills, and workflow understanding of nine Special Operations combat medics and Special Operations tactical medics. The course was based on a flipped classroom model with a total time of 43 hours, consisting of an online component followed by live lectures and hands-on workshops. The effectiveness of the course was determined using a knowledge exam, expert ratings of manual skills using a global rating scale, and an objective structured clinical skills examination (OSCE).

RESULTS

The average knowledge exam score of the medics increased from pre-course (56% ± 6.8%) to post-course (80% ± 5.0%, p < .001). Based on expert ratings, their manual skills improved from baseline to day 4 of the course for image finding (p = .007), image optimization (p = .008), image acquisition speed (p = .008), final image quality (p = .008), and global assessment (p = .008). Their average score at every OSCE station was > 91%.

CONCLUSION

A comprehensive multimodal training program can be used to improve military medics' ultrasound knowledge, manual skills, and workflow understanding for various applications of ultrasound. Further research is required to develop a reliable, sustainable course.

Three-Dimensional Printing of Patient-Specific Heart Valves: Separating Facts From Fiction and Myth From Reality

The development of prosthetic heart valves by Dr. Charles Hufnagel in 1952 was a major clinical innovation; however, it was not an ideal solution. Mechanical prosthetic heart valves are rigid, immunogenic, require anticoagulation, do not grow with the patient, and have a finite life.¹ An ideal prosthetic valve should overcome all these limitations. Considering the prevalence of valvular heart disorders, there is considerable interest in the creation of patient-specific heart valves. Following the introduction of three-dimensional (3D) printing in 1986 by Chuck Hill, rapid advances in multimodality 3D imaging and modeling have led to a generation of tangible replicas of patient-specific anatomy. The science of organogenesis has gained importance for a multitude of valid reasons: as an alternate source of organs, for realistic drug testing, as an alternative to animal testing, and for transplants that grow with the patient. What scientists imagined to be seemingly impossible in the past now seems just a step away from becoming a reality. However, due to the disruptive nature of this technology, often there are commercially-motivated claims of originality and overstatement of the scope and applicability of 3D printing. It often is difficult to separate fact from fiction and myth from reality. In this manuscript, the authors have reviewed the historic perspective, status of the basic techniques of organogenesis with specific reference to heart valves, and their potential.

Motion-Tracking Machines and Sensors: Advancing Education Technology

Graduate medical education is predominantly based on a time-based apprenticeship model, with implied acquisition of proficiency after a pre-set amount of clinical exposure. While motion metrics have been used previously to measure skill performance indicators, these assessments have largely been performed on a summative scale to describe the performance of complete tasks or procedures. By segmenting performances of interest and assessing the essential elements individually, a more comprehensive understanding of the aspects in need of improvement for a learner can be obtained. The purpose of this review is to discuss technologies applicable to motion tracking, their benefits and limitations, approaches to data processing, and potential applications based on recent improvements in this technology. Objective analysis of motion metrics may improve educational standards of learning and efficiency by both standardizing the feedback process for trainees and reducing the volume of instructors required to facilitate practice sessions. With rigorous validation and standardization, motion metric assessment may also prove useful to demonstrate competency in technical procedures as part of a comprehensive certification process.

Regional Anaesthesia for Lower Extremity Amputation is Associated with Reduced Post-operative Complications Compared with General Anaesthesia

OBJECTIVE

Primary and secondary lower extremity amputation, performed for patients with lower extremity arterial disease, is associated with increased post-operative morbidity. The aim of the study was to assess the impact of regional anaesthesia vs. general anaesthesia on post-operative pulmonary complications.

METHODS

A retrospective analysis of 45 492 patients undergoing lower extremity amputation between 2005 and 2018 was conducted using data from the American College of Surgeons National Safety Quality Improvement Program database. Multivariable logistic regression was carried out to assess differences in primary outcome of post-operative pulmonary complications (pneumonia or respiratory failure requiring re-intubation) within 48 hours and 30 days after surgery between patients receiving regional (RA) or general anaesthesia (GA). Secondary outcomes included post-operative blood transfusion, septic shock, re-operation, and post-operative death within 30 days.

RESULTS

Of 45 492 patients, 40 026 (88.0%) received GA and 5 466 (12.0%) RA. Patients who received GA had higher odds of developing pulmonary complications at 48 hours (2.1% vs. 1.4%; adjusted odds ratio [aOR] 1.39, 95% confidence interval [CI] 1.09 - 1.78; p = .007) and within 30 days (6.3% vs. 5.9%; aOR 1.15, 95% CI 1.09 - 1.78; p = .039). The odds of blood transfusions (aOR 1.11, 95% CI 1.02 - 1.21; p = .017), septic shock (aOR 1.29, 95% CI 1.03 - 1.60; p = .025) and re-operation (OR 1.26, 95% CI 1.03 - 1.53; p = .023) were also higher for patients who received GA vs. patients who received RA. No difference in mortality rate was observed between patients who received GA and those who received RA (5.7% vs. 7.1%; odds ratio 0.95, 95% CI 0.84 - 1.07).

CONCLUSION

A statistically significant reduction in pulmonary complications was observed in patients who received RA for lower extremity amputation compared with GA.

Echocardiographic Assessment of the Mitral Valve for Suitability of Repair: An Intraoperative Approach From a Mitral Center

Intraoperative echocardiography of the mitral valve in the precardiopulmonary bypass period is an integral part of the surgical decision-making process for assessment of suitability for repair. Although there are comprehensive reviews in the literature regarding echocardiographic examination of the mitral valve, the authors present a practical stepwise algorithmic workflow to make objective recommendations. Advances in echocardiography allow for quantitative geometric analyses of the mitral valve, along with precise assessment of the valvular apparatus with three-dimensional echocardiography. In the precardiopulmonary bypass period, echocardiographers are required to diagnose and quantify valvular dysfunction, assess suitability for repair, assist in annuloplasty ring sizing, and determine the success or failure of the surgical procedure. In this manuscript the authors outline an algorithmic approach to intraoperative echocardiography examination using two-dimensional and three-dimensional modalities to objectively analyze mitral valve function and assist in surgical decision-making.

Three-Dimensional Transesophageal Echocardiography Simulator: New Learning Tool for Advanced Imaging Techniques

The use of intraoperative three-dimensional (3D) transesophageal echocardiography (TEE) has grown exponentially in recent years. Three-dimensional TEE technology has evolved to allow for real-time display of 3D images and, thus, has become the standard of care for the evaluation of cardiac anatomy and function. Its use has provided a new dimension of clinical insight when managing patients for cardiac surgery or structural heart interventions. While the intraoperative utility of 3D TEE has expanded, there has been a slower advancement in the area of training and, specifically, simulator-based training in 3D TEE. This training is essential, as the skill set involved in acquiring 3D data sets differs from that of two-dimensional (2D) TEE and requires users to be able to appreciate how 3D anatomic display differs from that of tomographic cross-sectional 2D imaging. This added skill set requires mental reconstruction and spatial reorientation to appreciate the added elevational dimension in frustum-based imaging and is best achieved in a simulation environment rather than the busy operating room. In this review article, the authors evaluate the functionality of a 3D TEE simulator and how simulators such as this can establish preclinical proficiency in novices in the expanding area of advanced 3D TEE imaging.

Enhanced Post-Operative Recovery with Continuous Peripheral Nerve Block After Lower Extremity Amputation

BACKGROUND

Despite progress in perioperative care standards, there has not been a significant risk reduction in morbidity and mortality rates of lower extremity amputations, an intermediate risk surgery performed on high risk patients. The single-shot peripheral nerve block has shown equivocal impact on postoperative course following lower extremity amputation. Hence, we assessed the potential of preemptive use of continuous catheter-based peripheral nerve block in lower extremity amputations for reduction in pulmonary complications, acute post-operative pain scores, and opioid use in post-operative period.

METHODS

A retrospective review of a quality improvement project initiated in 2018 was conducted to compare outcomes amongst general anesthesia in combination with a catheter-based peripheral nerve block (catheter group) and general anesthesia alone in patients receiving lower extremity amputation. The rate of postoperative pulmonary complications was identified as a primary endpoint. The secondary outcomes assessed were acute post-operative pain scores and opioid consumption up to 48 hours. Our analysis was adjusted for potential confounding variables inclusive of demographics, medical comorbidities, type of surgical procedure and smoking status.

RESULTS

Ninety-six patients were included in the study (61 in the general anesthesia group, 35 in the catheter group). After adjusting for baseline demographics, comorbidities, surgical technique and smoking status, the odds of postoperative pulmonary complications were significantly lower with catheter-based peripheral nerve block in comparison to general anesthesia alone, OR 0.11 [95% CI, 0.01- 0.88] (P = 0.048). The decrease in acute pain scores was also observed in the catheter group when compared to general anesthesia alone, OR 0.72 [95% CI, 0.56 - 0.93] (P = 0.012). Similarly, the opioid consumption was also lower in the catheter group in comparison to general anesthesia alone, OR 0.97 [95% CI, 0.95 - 0.99] (P = 0.025).

CONCLUSION

Preemptive use of continuous peripheral nerve block in patients undergoing lower extremity amputation reduces the incidence of pulmonary complications, acute postoperative pain scores and narcotic use in post-operative period.

Simplified Algorithm for Evaluation of Perioperative Hypoxia and Hypotension (SALVATION): A Practical Echo-guided Approach Proposal

Despite the valuable use of modern applications of perioperative ultrasound across multiple disciplines, there have been limitations to its implementation, restricting its impact on patient-based clinical outcomes. Point-of-care ultrasound evaluation of hypoxia and hypotension is an important tool to assess the underlying undifferentiated etiologies in a timely manner. However, there is a lack of consensus on the formal role of ultrasound during evaluation of perioperative hypoxia or hypotension. The previous ultrasound algorithms have adopted a complex technique that possibly ignore the pathophysiologic mechanisms underlying the conditions presenting in a similar fashion. The authors here propose a simple, sequential and focused multiorgan approach, applicable for the evaluation of perioperative hypotension and hypoxia in emergency scenarios. The authors believe this approach will enhance the care provided in the postanesthesia care unit, operating room, and intensive care unit.

Closed Bronchoscopy System: An Innovative Approach to Minimize Aerosolization During Bronchoscopy

Health care workers performing aerosolizing procedures on patients with transmissible infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at high-risk for disease acquisition. Current guidelines designed to protect health care workers during aerosolizing procedures prioritize personal protective equipment and enhanced infection control techniques, in particular during procedures such as intubation. To date, little emphasis has been placed on risk mitigation in the setting of bronchoscopy, a procedure that has significant aerosolization potential. Herein, we present an innovative closed bronchoscopy system designed to reduce aerosolization during bronchoscopy.

Workflow of Ultrasound-Guided Arterial Access

Arterial line cannulations frequently are performed in various clinical settings to facilitate hemodynamic monitoring and metabolic assessments. Palpation-guided technique generally is performed due to the superficial nature of the peripheral arteries; however, this approach may be challenging in patients with obesity, edema, and hypotension. Difficult line placements are a significant contributor of reduced operating room efficiency due to time delays seen in procedural workflow. Real-time ultrasound guidance is shown to improve success rates of arterial cannulation and reduction in multiple attempts, leading to time efficiency and less likelihood of arterial spasms or hematoma formation. In this report, the authors demonstrate the workflow of ultrasound-guided arterial line cannulation, outline the features of their institutional multi-modal training project for quality improvement, and evaluate the possible effect of the initiative on surgical delays seen with difficult line placements.

Analysis of Kinematic Differences in Hand Motion between Novice and Experienced Operators in IR: A Pilot Study

PURPOSE

To prospectively validate electromagnetic hand motion tracking in interventional radiology to detect differences in operator experience using simulation.

METHODS

Sheath task: Six attending interventional radiologists (experts) and 6 radiology trainees (trainees) placed a wire through a sheath and performed a "pin-pull" maneuver, while an electromagnetic motion detection system recorded the hand motion. Radial task: Eight experts and 12 trainees performed palpatory radial artery access task on a radial access simulator. The trainees repeated the task with the nondominant hand. The experts were classified by their most frequent radial artery access technique as having either palpatory, ultrasound, or overall limited experience. The time, path length, and number of movements were calculated. Mann-Whitney U tests were used to compare the groups, and P < .05 was considered significant.

RESULTS

Sheath task: The experts took less time, had shorter path lengths, and used fewer movements than the trainees (11.7 seconds ± 3.3 vs 19.7 seconds ± 6.5, P < .01; 1.1 m ± 0.3 vs 1.4 m ± 0.4, P < .01; and 19.5 movements ± 8.5 vs 31.0 movements ± 8.0, P < .01, respectively). Radial task: The experts took less time, had shorter path lengths, and used fewer movements than the trainees (24.2 seconds ± 10.6 vs 33.1 seconds ± 16.9, P < .01; 2.0 m ± 0.5 vs 3.0 m ± 1.9, P < .001; and 36.5 movements ± 15.0 vs 54.5 movements ± 28.0, P < .001, respectively). The trainees had a shorter path length for their dominant hand than their nondominant hand (3.0 m ± 1.9 vs 3.5 m ± 1.9, P < .05). The expert palpatory group had a shorter path length than the ultrasound and limited experience groups (1.8 m ± 0.4 vs 2.0 m ± 0.4 and 2.3 m ± 1.2, respectively, P < .05).

CONCLUSIONS

Electromagnetic hand motion tracking can differentiate between the expert and trainee operators for simulated interventional tasks.

Cardiopulmonary Bypass Suppresses Forkhead Box O3 and Downstream Autophagy in the Diabetic Human Heart

BACKGROUND

Autophagy is an integral component of cellular homeostasis and metabolism. The exact mechanism of impaired autophagy in diabetes mellitus is unknown. Forkhead Box O3 (FOXO3α) is a key regulator of oxidative stress-related responses. We hypothesize FOXO3α is a direct upstream regulator of the autophagy pathway, and its upregulation is compromised in diabetic patients during stress of cardiopulmonary bypass (CPB).

METHODS

The study enrolled 32 diabetic and 33 nondiabetic patients undergoing a cardiac surgical procedure on CPB. Right atrial tissue and serum samples were collected before and after CPB per protocol. A set of key components were quantitatively assessed and compared by microarray, immunoblotting, and immunohistochemistry studies. Data were analyzed using paired or unpaired student test. A P of <.05 or less was considered significant.

RESULTS

Serum microarray showed FOXO3α was upregulated in the diabetic vs nondiabetic group after CPB (P = .033), autophagy-related 4B gene and Beclin 1 gene were greatly upregulated in the nondiabetic group (P = .028 and P = .002, respectively). On immunoblotting, there was upregulation of FOXO3α in the nondiabetic patients after CPB (P = .003). There were increased levels of Beclin-1, Bcl-2, and light chain 3B after CPB in the nondiabetic group only (P = .016, P = .005, P = .002, respectively). Sirtuin 1, Unc-51-like autophagy activating kinase 1 (ULK1), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α), and mammalian target of rapamycin (mTOR) were not significantly changed in the nondiabetic group after CPB.

CONCLUSIONS

Compared with nondiabetic patients, there was no significant upregulation of FOXO3α in diabetic patients, which could possibly explain the lack of upregulation of the autophagy process after CPB. FOXO3α could potentially serve as a therapeutic target to improve cellular homeostasis.

Handheld Point-of-Care Ultrasound Probes: The New Generation of POCUS

Recent advances in ultrasound technology have made ultrasound equipment more versatile, portable, and accessible than ever. Modern handheld, ultra-portable ultrasound devices have been developed by multiple companies and are contributing to make bedside ultrasound evaluation a practice available to all physicians. The significance of making point-of-care ultrasound (POCUS) a common practice that all physicians eventually can use in the evaluation of their patients is changing the way medicine is practiced, allowing physicians to quickly obtain valuable information to complement the traditional physical examination. Despite the proven benefits of using bedside ultrasound imaging as a part of the patient evaluation and for procedure guidance, adoption of this technology still is not widespread among anesthesiology clinicians nor is there uniform teaching of ultrasound skills to anesthesia residents and faculty. Among obstacles that have been identified as precluding achievement of the goal of widespread utilization of POCUS among anesthesia professionals and trainees, are the availability of equipment for all physicians when it is needed and lack of instructor supervision for trainees who desire to use ultrasound but do not always have an instructor knowledgeable in POCUS with them when an ultrasound examination is warranted. Herein, the characteristics, advantages, and limitations of available ultra-portable, handheld ultrasound devices are analyzed, with a focus on the Butterfly iQ (Butterfly Network, Inc, Guilford, CT) pocket probe, which is available at the authors’ institution, and how some of its features, such as the capacity to emulate multiple transducers and its cloud-sharing and teleguidance technology, may contribute to increase the availability and use of POCUS by anesthesia clinicians.

Impact of Left Atrial Appendage Exclusion on Short-Term Outcomes in Isolated Coronary Artery Bypass Graft Surgery

BACKGROUND

The objective of this study was to evaluate the impact of left atrial appendage (LAA) exclusion on short-term outcomes in patients with atrial fibrillation undergoing isolated coronary artery bypass graft surgery.

METHODS

We queried the 2010 to 2014 National Readmissions Database for patients who underwent coronary artery bypass graft repair with and without LAA ligation by using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes (International Classification of Diseases, Ninth Revision, Clinical Modification: 36.1xx). Only patients with a history of atrial fibrillation were included in our analysis. The primary outcome of our study was 30-day readmissions following discharge. Secondary outcomes were in-hospital mortality and stroke. To assess the postoperative outcomes, we used multivariate logistic regression models to adjust for clinical and demographic covariates.

RESULTS

In total, we analyzed 253 287 patients undergoing coronary artery bypass graft surgery, 7.0% of whom received LAA closure. LAA exclusion was associated with a greater risk of postoperative respiratory failure (8.2% versus 6.2%, P<0.0001) and acute kidney injury (21.8% versus 18.5%, P<0.0001), but it did not significantly change the rate of blood transfusions or occurrence of cardiac tamponade. LAA exclusion was associated with a nonsignificant reduction in stroke (7.9% versus 8.6%, P=0.12), no difference in in-hospital mortality (2.2% versus 2.2% P=0.99), and a greater risk of 30-day readmission (16.0% versus 9.6%, P<0.0001). After covariate adjustment, LAA ligation remained a significant predictor of 30-day readmission (odds ratio, 1.640 [95% CI, 1.603-1.677], P<0.0001).

CONCLUSIONS

LAA exclusion during isolated coronary artery bypass graft surgery in patients with atrial fibrillation is associated with a higher rate of 30-day readmission. Postoperative measures to mitigate the loss of the hormonal and hemodynamic effects of the LAA may increase the therapeutic benefit of this procedure.

Tool to improve qualitative assessment of left ventricular systolic function

Interactive online learning tools have revolutionized graduate medical education and can impart echocardiographic image interpretive skills. We created self-paced, interactive online training modules using a repository of echocardiography videos of normal and various degrees of abnormal left ventricles. In this study, we tested the feasibility of this learning tool. Thirteen anesthesia interns took a pre-test and then had 3 weeks to complete the training modules on their own time before taking a post-test. The average score on the post-test (74.6% ± 11.08%) was higher than the average score on the pre-test (57.7% ± 9.27%) (P < 0.001). Scores did not differ between extreme function (severe dysfunction or hyperdynamic function) and non-extreme function (normal function or mild or moderate dysfunction) questions on both the pre-test (P = 0.278) and post-test (P = 0.093). The interns scored higher on the post-test than the pre-test on both extreme (P = 0.0062) and non-extreme (P = 0.0083) questions. After using an online educational tool that allowed learning on their own time and pace, trainees improved their ability to correctly categorize left ventricular systolic function. Left ventricular systolic function is often a key echocardiographic question that can be difficult to master. The promising performance of this educational resource may lead to more time- and cost-effective methods for improving diagnostic accuracy among learners.

Crossed Swords Sign: A 3-Dimensional Echocardiographic Appearance

Intraoperative evaluation of mitral regurgitation is a complex undertaking. Bileaflet prolapse/flail can result in divergent mitral regurgitation jets with a characteristic "crossed swords sign" appearance. We present a case of divergent mitral regurgitation jets that were detected intraoperatively and evaluated using 3-dimensional imaging. The accurate assessment of eccentric mitral regurgitation jets, especially bilateral eccentric mitral regurgitation jets, is challenging before surgical repair. Intraoperative 3-dimensional transesophageal echocardiography with and without color-flow Doppler can significantly improve the localization of the anatomical lesion.

Impact of left ventricular outflow tract flow acceleration on aortic valve area calculation in patients with aortic stenosis

Objective

Due to its circular shape, the area of the proximal left ventricular tract (PLVOT) adjacent to aortic valve can be derived from a single linear diameter. This is also the location of flow acceleration (FA) during systole, and pulse wave Doppler (PWD) sample volume in the PLVOT can lead to overestimation of velocity (V₁) and the aortic valve area (AVA). Therefore, it is recommended to derive V₁ from a region of laminar flow in the elliptical shaped distal LVOT (away from the annulus). Besides being inconsistent with the assumptions of continuity equation (CE), spatial difference in the location of flow and area measurement can result in inaccurate AVA calculation. We evaluated the impact of FA in the PLVOT on the accuracy of AVA by continuity equation (CE) in patients with aortic stenosis (AS).

Methods

CE-based AVA calculations were performed in patients with AS once with PWD-derived velocity time integral (VTI) in the distal LVOT (VTI_LVOT) and then in the PLVOT to obtain a FA velocity profile (FA-VTI_LVOT) for each patient. A paired sample t-test (P < 0.05) was conducted to compare the impact of FA-VTI_LVOT and VTI_LVOT on the calculation of AVA.

Result

There were 46 patients in the study. There was a 30.3% increase in the peak FA-VTI_LVOT as compared to the peak VTI_LVOT and AVA obtained by FA-VTI_LVOT was 29.1% higher than obtained by VTI_LVOT.

Conclusion

Accuracy of AVA can be significantly impacted by FA in the PLVOT. LVOT area should be measured with 3D imaging in the distal LVOT.

Immediate Preoperative Transthoracic Echocardiography for the Prediction of Postoperative Atrial Fibrillation in High-Risk Cardiac Surgery

OBJECTIVE

The present study aimed to validate the utility of bedside cardiac ultrasound to identify patients for the risk of postoperative atrial fibrillation (POAF).

DESIGN

A prospective cohort study of consecutive patients.

SETTING

Single-center tertiary referral center.

PARTICIPANTS

After Institutional Review Board consent, 169 patients undergoing elective cardiac surgery were enrolled in the study.

INTERVENTIONS

A preoperative transthoracic echocardiographic interrogation assessing diastolic function was performed. Measurements were assessed offline with experienced echocardiographers blinded to clinical outcomes.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was POAF during the first 72 hours after surgery. A total of 169 patients completed the study, 44 of whom (26.0%) developed POAF, and 39 (25.2%) had diastolic dysfunction. Patients with POAF had a higher rate of postoperative heart failure, reintubation within 24 hours of surgery, and length of stay (p = 0.002, 0.01, and 0.0006, respectively). Predictors significant for POAF included increasing age, left atrial volume indexed to body surface area (LAVI), and diastolic dysfunction (p = 0.02, 0.0001, and 0.001, respectively). Multivariate spline regressions demonstrated a nonlinear correlation between increasing LAVI and risk of POAF.

CONCLUSION

Left atrial volume can be assessed efficiently preoperatively to provide superior risk stratification over clinical factors and diastolic parameters alone for the prediction of POAF. Furthermore, the present study demonstrated that the cutoffs of chamber quantification currently used do not appropriately capture the increased risk of POAF. Thus, LAVI provides a simple measure to identify patients who are in need of targeted prophylaxis for POAF.