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High-flow oxygen therapy using a tracheostomy tube is a promising clinical approach to reduce the work of breathing in tracheostomized patients. Positive end-expiratory pressure (PEEP) is usually applied during oxygen inflow to improve oxygenation by preventing end-expiratory lung collapse. However, much is still unknown about the geometrical effects of PEEP, especially regarding tracheostomy tube connectors (or adapters). Quantifying the degree of end-expiratory pressure (EEP) that takes patient-specific spirometry into account would be useful in this regard, but no such framework has been established yet. Thus, a platform to assess PEEP under respiration was developed, wherein three-dimensional simulation of airflow in a tracheostomy tube connector is coupled with a lumped lung model. The numerical model successfully reflected the magnitude of EEP measured experimentally using a lung phantom. Numerical simulations were further performed to quantify the effects of geometrical parameters on PEEP, such as inlet angles and rate of stenosis in the connector. Although sharp inlet angles increased the magnitude of EEP, they cannot be expected to achieve clinically reasonable PEEP. On the other hand, geometrical constriction in the connector can potentially result in PEEP as obtained with conventional nasal cannulae. [ABSTRACT FROM AUTHOR]

Background: Pulmonary embolism (PE) resulting from venous thromboembolism is a leading cause of maternal mortality in pregnancy. In patients with massive PE and hemodynamic instability, the treatment options often considered are thrombolytics, inferior vena caval filters, or embolectomy. We report here the case of a patient with massive PE at 28 weeks' gestation, who underwent emergency pulmonary embolectomy via cardiopulmonary bypass. Case presentation: A 35-year old primigravida with a history of massive PE at 25 weeks of gestation was referred to our hospital at 28 weeks of gestation, following treatment failure after insertion of an inferior vena cava filter and heparin administration. Emergency thrombectomy was performed, and intracardiac echography was used for intraoperative fetal heart rate monitoring. However, the patient developed hemodynamic collapse following anesthesia induction; hence, emergency cardiopulmonary bypass (CPB) was performed via median sternotomy. Thrombectomy and tricuspid valve plication were performed under cardiac arrest. After confirming postoperative hemostasis, heparin administration was resumed. At 40 weeks of gestation, labor was induced under epidural analgesia. Both mother and child were discharged with no complications. Conclusion: In conclusion, intracardiac echography is useful for fetal heart rate monitoring during emergency cardiac surgery in pregnancy. Careful CPB management is important to maintain uteroplacental blood flow. Although there is no consensus on the delivery methods in such cases, epidural analgesia during labor was useful in reducing cardiac load and wound traction. [ABSTRACT FROM AUTHOR]

Right ventricular assist device (RVAD) implantation is one type of surgical treatment used for right heart failure. It is important to assess right ventricular (RV) function precisely when RVAD withdrawal is considered. Although assessment of RV function is difficult due to its complicated shape and contraction pattern, the volumetric analysis method of three-dimensional (3D) transesophageal echocardiography (TEE) has been developed and is useful for this task. We report the case of a 79-year-old man who successfully underwent RVAD withdrawal and evaluation using 3D TEE. 3D TEE had an important role in determining the timing of withdrawal from RVAD in this case. [ABSTRACT FROM AUTHOR]

Objective: Losartan, an angiotensin II receptor blocker (ARB), has been reported to promote sodium excretion and show an enhanced antihypertensive effect when used in combination with hydrochlorothiazide (HCTZ). We investigated the effects of losartan monotherapy and combination therapy together with HCTZ on cardiac function in hypertensive rats using echocardiography. Methods: Spontaneously hypertensive rats ( n = 21) fed on high-salt diet (8 % NaCl) for 13 weeks were randomly assigned to rats without medication (HS, n = 7), those medicated with ARB (ARB, losartan 30 mg/kg/day, n = 8), and those with ARB and HCTZ (ARB + HCTZ, losartan 30 mg/kg/day + HCTZ 10 mg/kg/day, n = 6). Blood pressure measurements and echocardiography were performed at 13, 17, and 29 weeks of age. After the end of the protocol, the proportion of cardiac muscle fibrosis was measured histologically. Results: In the HS group, blood pressure and left ventricular mass/body weight (LV mass/BW) increased, and % fractional shortening (%FS) and early diastolic mitral annular velocity ( e′) decreased significantly with age. In the ARB group, although blood pressure and %FS were maintained, LV mass/BW increased with age as in the HS group, and e′ decreased. In the ARB + HCTZ group, blood pressure decreased and LV mass/BW, %FS, and e′ were maintained. The progression of myocardial fibrosis was clearly prevented in rats treated with ARB. Conclusion: ARB was shown to inhibit systolic disorder and myocardial fibrosis in hypertensive rats. Combination therapy proved to be more effective than monotherapy and is also effective in inhibiting diastolic disorders. [ABSTRACT FROM AUTHOR]