Publications

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.

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.

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.

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.

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.

Transseptal puncture is an increasingly common procedure undertaken to gain access to the left side of the heart during structural heart disease interventions. Precision guidance during this procedure is paramount to ensure success and patient safety. As such, multimodality imaging, such as echocardiography, fluoroscopy, and fusion imaging, is routinely used to guide safe transseptal puncture. Despite the use of multimodal imaging, there is currently no uniform nomenclature of cardiac anatomy between the various imaging modes and proceduralists, and echocardiographers tend to use imaging modality-specific terminology when communicating among the various imaging modes. This variability in nomenclature among imaging modes stems from differing anatomic descriptions of cardiac anatomy. Given the required level of precision in performing transseptal puncture, a clearer understanding of the basis of cardiac anatomic nomenclature is required by both echocardiographers as well as proceduralists; enhanced understanding can help facilitate communication across specialties and possibly improve communication and safety. In this review, the authors highlight the variation in cardiac anatomy nomenclature among various imaging modes.

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.

Transcatheter edge-to-edge repair (TEER) of the mitral valve is a complex procedure requiring continuous image guidance with 2-dimensional and 3-dimensional transesophageal echocardiography. In this context, the role of the echocardiographer is of paramount importance. Training in interventional echocardiography for procedures such as TEER requires comprehending the complicated workflow of the hybrid operating room and advanced imaging skills that go beyond traditional echocardiography training to guide the procedure. Despite TEER being more commonly performed, the training structure for interventional echocardiographers is lagging, with many practitioners not having any formal training in image guidance for this procedure. In this context, novel training strategies must be developed to increase exposure and aid training. In this review, the authors present a step-wise approach to training for image guidance during TEER of the mitral valve. The authors have deconstructed this complex procedure into modular components and have incremental stages of training based on different steps of the procedure. At each step, trainees must demonstrate proficiency before advancing to the next step, thus ensuring a more structured approach to attaining proficiency in this complex procedure.

BACKGROUND: Graduate medical education is being transformed from a time-based training model to a competency-based training model. While the application of ultrasound in the perioperative arena has become an expected skill set for anesthesiologists, clinical exposure during training is intermittent and nongraduated without a structured program. We developed a formal structured perioperative ultrasound program to efficiently train first-year clinical anesthesia (CA-1) residents and evaluated its effectiveness quantitatively in the form of a proficiency index.

METHODS: In this prospective study, a multimodal perioperative ultrasound training program spread over 3 months was designed by experts at an accredited anesthesiology residency program to train the CA-1 residents. The training model was based on self-learning through web-based modules and instructor-based learning by performing perioperative ultrasound techniques on simulators and live models. The effectiveness of the program was evaluated by comparing the CA-1 residents who completed the training to graduating third-year clinical anesthesia (CA-3) residents who underwent the traditional ultrasound training in the residency program using a designed index called a "proficiency index." The proficiency index was composed of scores on a cognitive knowledge test (20%) and scores on an objective structured clinical examination (OSCE) to evaluate the workflow understanding (40%) and psychomotor skills (40%).

RESULTS: Sixteen CA-1 residents successfully completed the perioperative ultrasound training program and the subsequent evaluation with the proficiency index. The total duration of training was 60 hours of self-based learning and instructor-based learning. There was a significant improvement observed in the cognitive knowledge test scores for the CA-1 residents after the training program (pretest: 71% [0.141 ± 0.019]; posttest: 83% [0.165 ± 0.041]; P < .001). At the end of the program, the CA-1 residents achieved an average proficiency index that was not significantly different from the average proficiency index of graduating CA-3 residents who underwent traditional ultrasound training (CA-1: 0.803 ± 0.049; CA-3: 0.823 ± 0.063, P = .307).

CONCLUSIONS: Our results suggest that the implementation of a formal, structured curriculum allows CA-1 residents to achieve a level of proficiency in perioperative ultrasound applications before clinical exposure.