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Catheterization for structural heart disease (SHD) requires fluoroscopic guidance, which exposes health care professionals to radiation exposure risk. Nevertheless, existing freestanding radiation shields for anesthesiologists are typically simple, uncomfortable rectangles. Therefore, we devised a new perforated radiation shield that allows anesthesiologists and echocardiographers to access a patient through its apertures during SHD catheterization. No report of the relevant literature has described the degree to which the anesthesiologist’s radiation dose can be reduced by installing radiation shields. For estimating whole-body doses to anesthesiologists and air dose distributions in the operating room, we used a Monte Carlo system for a rapid dose-estimation system used with interventional radiology. The simulations were performed under four conditions: no radiation shield, large apertures, small apertures and without apertures. With small apertures, the doses to the lens, waist and neck surfaces were found to be comparable to those of a protective plate without an aperture, indicating that our new radiation shield copes with radiation protection and work efficiency. To simulate the air-absorbed dose distribution, results indicated that a fan-shaped area of the dose rate decrease was generated in the area behind the shield, as seen from the tube sphere. For the aperture, radiation was found to wrap around the backside of the shield, even at a height that did not match the aperture height. The data presented herein are expected to be of interest to all anesthesiologists who might be involved in SHD catheterization. The data are also expected to enhance their understanding of radiation exposure protection.

IntroductionThe possibility of hypercoagulability during the perioperative period of transcatheter aortic valve implantation (TAVI) has been noted; however, there is still a controversy regarding the appropriate perioperative antithrombotic therapy. The study investigated coagulation and platelet functions during the TAVI perioperative period using thromboelastography (TEG) 6s platelet mapping.MethodsA prospective observational study was conducted on 25 patients undergoing TAVI. TEG platelet mapping was performed at three time points: on admission to the operating room (before heparinisation), on postoperative day (POD) 1 and on POD 3. Perioperative changes observed included: maximum clot strength (MAHKH), clot strength without platelet function (MAActF), time to initiation of clots formation by coagulation factors (RHKH) and platelet function (Gp). Gpis activated by thrombin, and not affected by antiplatelet agents. It is calculated as [(5000×MAHKH)/(100 – MAHKH)] − [(5000×MAActF)/(100 – MAActF)]. Finally, MAADP/AAand GADP/AA, which reflect clot strength and platelet aggregation mediated by ADP/thromboxane A2receptors, respectively, were also examined using the same method as for Gp.ResultsMAHKHcontinued to decrease until POD 3, indicating antithrombotic change after TAVI. Gpcontinuously decreased for 3 days after TAVI, while MAActFincreased significantly on POD 3. Furthermore, RHKHshortened on POD 1 and POD 3, suggesting increased coagulation capacity after TAVI. Finally, GADPin clopidogrel-naive patients was reduced for 3 days after TAVI, while GAAin aspirin-naive patients showed no significant change perioperatively.ConclusionsIn this study involving TEG platelet mapping, coagulation capacity increased while platelet function decreased, resulting in antithrombotic change for 3 days after TAVI. The ADP receptor system may be implicated in the decreased platelet function. These results may be useful for considering optimal perioperative antithrombotic therapy in TAVI.

Background No reports to date have assessed the procedural patterns of high-intensity transient signals (HITS) by monitoring blood flow in cervical arteries. The aim of this study was to examine the sequential distribution of HITS in each procedural phase and predictive factors for HITS during transcatheter aortic valve implantation (TAVI) by monitoring blood flow in the common carotid artery. Methods This prospective observational study included 73 patients who underwent TAVI via the transfemoral artery approach. We continuously evaluated and analyzed HITS from administration of heparin to valve implantation. Results HITS peaked during balloon valvuloplasty (BAV), amounting to almost 30% of the total HITS count, followed by valve implantation [BAV 141 (73–186) and valve implantation 86 (64–126), respectively]. In univariate and multivariate analysis, the Agatston score of the aortic valve and low-density lipoprotein were confirmed as independent predictors of HITS frequency with logarithmically converted coefficients of 0.00015 (p Conclusions These results provide the first evidence that micro-emboli deriving from calcified burden were scattered primally during BAV, followed by valve implantation. The Agatston score may be a predictor for the amount of HITS.

Background Plastic bronchitis (PB) is a complication of Fontan surgery, results in the formation of mucus plug in the tracheobronchial tree, causing potentially fatal airway obstruction. We report critical airway emergency during general anesthesia in a child with plastic bronchitis. Case presentation A 5-year-old boy was scheduled for intrapulmonary lymphatic embolization through percutaneous catheterization under general anesthesia. He underwent Fontan surgery at the age of 2 and frequently developed respiratory failure due to plastic bronchitis. After induction of general anesthesia and tracheal intubation, mechanical ventilation became difficult even with an inspiratory pressure ≥ 50 mmHg due to airway obstruction. He expectorated a large mucus plug through the tracheal tube after administration of sugammadex, naloxone, and flumazenil, and respiratory condition was stabilized thereafter. Conclusion General anesthesia for a patient with plastic bronchitis should be planned with extracorporeal membrane oxygenation or cardiopulmonary bypass stand by.

In this paper, a new single-fed crossed V-dipole antenna for a circular polarization is proposed. This antenna is single-fed with four arms supporting the two V-dipoles on the reflector used as a balun as well as a 90° phase shift divider. The symmetrically placed supporting arms can be viewed as transmission lines. From the current distributions of the equivalent circuit of these lines, the input impedance of the V-dipoles and the circular polarization condition with regard to the antenna height and the stub location are derived. Based on these quantities, a circularly polarized antenna is designed and its characteristics are derived. It is found that there exists a structure for which the axial ratio can be made substantially wider than other antennas with a size of one-half wavelength. By means of experiments, the validity of the theoretical results is confirmed. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 85(11): 44–51, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.1136