Summative Objective Structured Clinical Examination Assessment at the End of Anesthesia Residency for Perioperative Ultrasound.

While standardized examinations and data from simulators and phantom models can assess knowledge and manual skills for ultrasound, an Objective Structured Clinical Examination (OSCE) could assess workflow understanding. We recruited 8 experts to develop an OSCE to assess workflow understanding in perioperative ultrasound. The experts used a binary grading system to score 19 graduating anesthesia residents at 6 stations. Overall average performance was 86.2%, and 3 stations had an acceptable internal reliability (Kuder-Richardson formula 20 coefficient >0.5). After refinement, this OSCE can be combined with standardized examinations and data from simulators and phantom models to assess proficiency in ultrasound.

Dynamic Three-Dimensional Geometry of the Aortic Valve Apparatus-A Feasibility Study.

OBJECTIVE: To provide (1) an overview of the aortic valve (AV) apparatus anatomy and nomenclature, and (2) data regarding the normal AV apparatus geometry and dynamism during the cardiac cycle obtained from three-dimensional transesophageal echocardiography (3D TEE). DESIGN: Retrospective feasibility study. SETTING: A single-center university teaching hospital. PARTICIPANTS: The study was performed on data of 10 patients with a nonregurgitant, nonstenotic aortic valve undergoing cardiac surgery. INTERVENTIONS: Intraoperative 3D TEE was performed on all the participants using the Siemens ACUSON SC2000 ultrasound system and Z6Ms transducer (Siemens Medical Systems, Mountainview, CA). MEASUREMENTS AND MAIN RESULTS: Dynamic offline analyses were performed with Siemens eSie valve analytical software in a semiautomated fashion. Forty-five parameters were exported of which 13 were selected and analyzed. The cardiac cycle was divided into 4 quartiles to account for frame-rate variations. The annulus, sinus of Valsalva (SoV) and sinotubular junction (STJ) areas, diameter, perimeter and height, aortic leaflet height, leaflet coaptation height, and aortic valve-mitral valve angle changed significantly during the cardiac cycle (p < 0.001). STJ expanded more than both the annulus and the SoV (p < 0.001). The maximum aortic valve leaflet height change was greater in the left and right versus noncoronary leaflet (p < 0.001). CONCLUSIONS: The semiautomated AV apparatus dynamic assessment using eSie valve software is a clinically feasible technique and can be performed readily in the operating room. It has the potential to significantly impact intraoperative decision-making in cases suitable for AV repair. The AV apparatus is a dynamic structure and demonstrates significant changes during the cardiac cycle.

Changes in Tricuspid Annular Geometry in Patients with Functional Tricuspid Regurgitation.

OBJECTIVE: To determine whether the indices of tricuspid annular dynamics that signify irreversible tricuspid valvular remodeling can improve surgical decision making by helping to better identify patients with functional tricuspid regurgitation who could benefit from annuloplasty. DESIGN: Retrospective analysis study. SETTING: Tertiary hospital. PARTICIPANTS: A total number of 55 patients were selected, 18 with functional tricuspid valve (TV) regurgitation and 37 normal nonregurgitant TVs. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: When comparing the basal, mid, and longitudinal diameters of the right ventricle between the nonregurgitant valve (NTR) group and the functional tricuspid regurgitation (FTR) group, tricuspid annulus was more dilated (p < 0.001, p = 0.001, and p = 0.006, respectively) and less nonplanar (p < 0.001) in the FTR group. At end-systole (ES), the posterolateral-anteroseptal axis was significantly greater in the FTR group than in the NTR group (mean difference = 7.15 mm; p < 0.001). The right ventricle in the FTR group was also significantly dilated with greater leaflet restriction (p = 0.015). CONCLUSIONS: As compared to NTR TVs, FTR is associated with identifiable indices of tricuspid annular structural changes that are indicative of irreversible remodeling.

Hemodynamic Testing of Patient-Specific Mitral Valves Using a Pulse Duplicator: A Clinical Application of Three-Dimensional Printing.

OBJECTIVE: To evaluate the feasibility of obtaining hemodynamic metrics of echocardiographically derived 3-dimensional printed mitral valve models deployed in a pulse-duplicator chamber. DESIGN: Exploratory study. SETTING: Tertiary-care university hospital. PARTICIPANTS: Percutaneous MitraClip procedure patient. INTERVENTIONS: Three-dimensional R-wave gated, full-volume transesophageal echocardiography images were obtained after deployment of the MitraClip device. A high-quality diastolic frame of the mitral valve was segmented using Mimics Innovation Suite and merged with a flange. The data were exported as a stereolithography (.stl) file, and a rigid 3-dimensional model was printed using a MakerBot Replicator 2 printer. A flexible silicone cast then was created and deployed in the pulse-duplicator chamber filled with a blood-mimicking fluid. MEASUREMENTS AND MAIN RESULTS: The authors were able to obtain continuous-wave Doppler tracings of the valve inflow with a transesophageal echocardiography transducer. They also were able to generate diastolic ventricular and atrial pressure tracings. Pressure half-time and mitral valve area were computed from these measurements. CONCLUSION: This pulse duplicator shows promising applications in hemodynamic testing of patient-specific anatomy. Future modifications to the system may allow for visualization and data collection of gradients across the aortic valve.

Decreased PGC-1α Post-Cardiopulmonary Bypass Leads to Impaired Oxidative Stress in Diabetic Patients.

BACKGROUND: The mechanism of mitochondrial dysfunction after cardiopulmonary bypass (CPB) in patients with diabetes mellitus lacks understanding. We hypothesized that impaired beta-oxidation of fatty acids leads to worsened stress response in this patient population after cardiac surgery. METHODS: After Institutional Review Board approval, right atrial tissue samples were collected from 35 diabetic patients and 33 nondiabetic patients before and after CPB. Patients with glycated hemoglobin of 6.0 or greater and a clinical diagnosis of diabetes mellitus were considered to be diabetic. Immunoblotting and microarray analysis were performed to assess protein and gene expression changes. Blots were quantified with ImageJ and analyzed using one-way analysis of variance with multiple Student's t test comparisons after normalization. All p values less than 0.05 were considered significant. Immunohistochemistry was performed for cellular lipid deposition assessment. RESULTS: Diabetic patients had significantly lower levels of PGC-1α before and after CPB (p < 0.01 for both) compared with nondiabetic patients. Several upstream regulators of PGC-1α (SIRT1 and CREB) were significantly higher in nondiabetic patients before CPB (p = 0.01 and 0.0018, respectively). Antioxidant markers (NOX4 and GPX4), angiogenic factors (TGF-ß, NT3, and Ang1), and the antiapoptotic factor BCL-xL were significantly lower in diabetic patients after CPB (p < 0.05). The expression of genes supporting mitochondrial energy production (CREB5 and SLC25A40) and angiogenic genes (p < 0.05) was significantly downregulated in diabetic patients after CPB. Immunohistochemistry results showed significantly increased lipid deposition in diabetic myocardial tissue. CONCLUSIONS: Decreased PGC-1α in diabetic patients may lead to impaired mitochondrial function and attenuated antiapoptotic and angiogenic responses after CPB. Therefore, PGC-1α and upstream regulators could serve as a target for improving beta-oxidation in diabetic patients.

Improving Clinical Proficiency Using a 3-Dimensionally Printed and Patient-Specific Thoracic Spine Model as a Haptic Task Trainer.

BACKGROUND AND OBJECTIVES: Advanced haptic simulators for neuraxial training are expensive, have a finite life, and are not patient specific. We sought to demonstrate the feasibility of developing a custom-made, low-cost, 3-dimensionally printed thoracic spine simulator model from patient computed tomographic scan data. This study assessed the model's practicality, efficiency as a teaching tool, and the transfer of skill set into patient care. METHODS: A high-fidelity, patient-specific thoracic spine model was used for the study. Thirteen residents underwent a 1-hour 30-minute training session prior to performing thoracic epidural analgesia (TEA) on patients. We observed another group of 14 residents who were exposed to the traditional method of training during their regional anesthesia rotation for thoracic epidural placement. The TEA was placed for patients under the supervision of attending anesthesiologists, who were blinded to the composition of the study and control groups. As a primary outcome, data were collected on successful TEAs, which was defined as a TEA that provided full relief of sensation across the entire surgical area as assessed by both a pinprick and temperature test. Secondary outcomes included whether any assistance from the attending physician was required and failed epidurals. RESULTS: A total of 27 residents completed the study (14 in the traditional training, 13 in the study group). We found that the residents who underwent training with the simulator had a significantly higher success rate (11 vs 4 successful epidural attempts, P = 0.002) as compared with the traditional training group. The control group also required significantly more assistance from the supervising anesthesiologist compared with the study group (5 vs 1 attempt requiring guidance). The number needed to treat (NNT) for the traditional training group was 1.58 patients over the study period with a 95% confidence interval of 1.55 to 1.61. CONCLUSIONS: By using patient-specific, 3-dimensionally printed, thoracic spine models, we demonstrated a significant improvement in clinical proficiency as compared with traditional teaching models.

Low-cost three-dimensional printed phantom for neuraxial anesthesia training: Development and comparison to a commercial model.

METHODS: Anonymized CT DICOM data was segmented to create a 3D model of the lumbar spine. The 3D model was modified, placed inside a digitally designed housing unit and fabricated on a desktop 3D printer using polylactic acid (PLA) filament. The model was filled with an echogenic solution of gelatin with psyllium fiber. Twenty-two staff anesthesiologists performed a spinal and epidural on the 3D printed simulator and a commercially available Simulab phantom. Participants evaluated the tactile and ultrasound imaging fidelity of both phantoms via Likert-scale questionnaire. RESULTS: The 3D printed neuraxial phantom cost $13 to print and required 25 hours of non-supervised printing and 2 hours of assembly time. The 3D printed phantom was found to be less realistic to surface palpation than the Simulab phantom due to fragility of the silicone but had significantly better fidelity for loss of resistance, dural puncture and ultrasound imaging than the Simulab phantom. CONCLUSION: Low-cost neuraxial phantoms with fidelity comparable to commercial models can be produced using CT data and low-cost infrastructure consisting of FLOS software and desktop 3D printers.

Percutaneous Valve in Valve Implantation for Dysfunctional Bioprosthetic Valves: A Case Report.

Percutaneous valve-in-valve therapy is a life-saving procedure for patients at high risk of reoperation due to dysfunctional bioprosthetic valves. We have reviewed 3 typical cases of a valve-in-valve procedure using high-quality images to demonstrate the suitability of this method for aortic, mitral, and tricuspid positions. Three-dimensional transesophageal echocardiography combined with other modalities such as computerized tomography and fluoroscopy are key elements for anesthesia and procedural guidance, especially as immediate tools to assess valvular function and specific procedure-related complications.

Artificial intelligence in mitral valve analysis.

BACKGROUND: Echocardiographic analysis of mitral valve (MV) has become essential for diagnosis and management of patients with MV disease. Currently, the various software used for MV analysis require manual input and are prone to interobserver variability in the measurements. AIM: The aim of this study is to determine the interobserver variability in an automated software that uses artificial intelligence for MV analysis. SETTINGS AND DESIGN: Retrospective analysis of intraoperative three-dimensional transesophageal echocardiography data acquired from four patients with normal MV undergoing coronary artery bypass graft surgery in a tertiary hospital. MATERIALS AND METHODS: Echocardiographic data were analyzed using the eSie Valve Software (Siemens Healthcare, Mountain View, CA, USA). Three examiners analyzed three end-systolic (ES) frames from each of the four patients. A total of 36 ES frames were analyzed and included in the study. STATISTICAL ANALYSIS: A multiple mixed-effects ANOVA model was constructed to determine if the examiner, the patient, and the loop had a significant effect on the average value of each parameter. A Bonferroni correction was used to correct for multiple comparisons, and P = 0.0083 was considered to be significant. RESULTS: Examiners did not have an effect on any of the six parameters tested. Patient and loop had an effect on the average parameter value for each of the six parameters as expected (P < 0.0083 for both). CONCLUSION: We were able to conclude that using automated analysis, it is possible to obtain results with good reproducibility, which only requires minimal user intervention.

Use of 3-Dimensional Printing to Create Patient-Specific Thoracic Spine Models as Task Trainers.

BACKGROUND AND OBJECTIVES: Thoracic epidural anesthesia is a technically challenging procedure with a high failure rate of 24% to 32% nationwide. Residents in anesthesiology have limited opportunities to practice this technique adequately, and there are no training tools available for this purpose. Our objective was to build a low-cost patient-specific thoracic epidural training model. METHODS: We obtained thoracic computed tomography scan data from patients with normal and kyphotic spine. The thoracic spine was segmented from the scan, and a 3-dimensional model of the spine was generated and printed. It was then placed in a customized wooden box and filled with different types of silicone to mimic human tissues. Attending physicians in our institution then tested the final model. They were asked to fill out a brief questionnaire after the identification of the landmarks and epidural space using ultrasound and real-time performance for a thoracic epidural on the model (Supplemental Digital Content 1, http://links.lww.com/AAP/A197). Likert scoring system was used for scoring. RESULTS: The time to develop this simulator model took less than 4 days, and the materials cost approximately $400. Fourteen physicians tested the model for determining the realistic sensation while palpating the spinous process, needle entry through the silicone, the "pop" sensation and ultrasound fidelity of the model. Whereas the tactile fidelity scores were "neutral" (3.08, 3.06, and 3.0, respectively), the ultrasound guidance and overall suitability for residents were highly rated as being the most realistic (4.85 and 4.0, respectively). CONCLUSIONS: It is possible to develop homemade, low-cost, patient-specific, and high-fidelity ultrasound guidance simulators for resident training in thoracic epidurals using 3-dimensional printing technology.