ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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A mock circulatory system (MCS) has been proven a useful tool in the development of a ventricular assist device. Nowadays a MCS aimed at the evaluation of pediatric blood pumps, which require many different considerations compared with that of adults, has become an urgent need. This article presents the details on how the dynamic process of the left ventricle, which is described in terms of the pressure-volume loop (P-V loop), and the properties of the circulation such as compliance and resistance are simulated by hydraulic elements. ⋯ At last a pediatric left ventricular assist device (LVAD) prototype is introduced for testing to further verify the effectiveness of the MCS. The experimental results indicate that this pediatric MCS is capable of reproducing basic hemodynamic characteristics of a child in both normal and pathological conditions and it is sufficient for testing a pediatric LVAD. Besides, most components constituting the main hydraulic part of this MCS are inexpensive off-the-shelf products, making the MCS easy and fast to build.
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Extracorporeal membrane oxygenation (ECMO) is recommended as a treatment modality for severe acute respiratory distress syndrome (PaO2/FiO2 ≤ 100 mm Hg with positive end-expiratory pressure ≥ 5 cm H2O) as defined by the Berlin definition. The reported usual duration of ECMO in these patients is 7-10 days. However, increasing reports of prolonged duration ECMO (>14 days) for respiratory failure document survival rates of 50-70% with native lung recovery, and ECMO bridge to lung transplantation has been performed at many centers. ⋯ We report a case of prolonged duration venovenous-ECMO (1,347 hours, 56.13 days), with native lung recovery and discuss treatment strategies to optimize native lung recovery in ECMO patients. The lung may have unexpected regenerative capacity with native lung recovery after prolonged mechanical support, similar to acute kidney injury and native renal recovery. We recommend redefining irreversible lung injury and futility in ECMO.
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Sedation practice in extracorporeal membrane oxygenation (ECMO) is challenging, and some studies suggest that pharmacokinetics of sedative drugs are altered by the circuitry components. We conducted an international survey of sedation practice in centers offering veno-venous ECMO for adult patients in collaboration with the Extracorporeal Life Support Organization. A total 102 respondents participated representing various experienced centers from around the world. ⋯ Responses from experienced users differed to those who reported less experience. Sedation practice in ECMO varies widely. Cooperative or responsive levels of sedation can frequently be achieved, and the drugs used differ from those used in non-ECMO patients.
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Left ventricular assist device (LVAD) implantation is associated with the risk of early postoperative right heart dysfunction, which may require urgent institution of mechanical right ventricular support. This is conventionally achieved by cannulation of the femoral vein or right atrial appendage for the inflow and the pulmonary artery for the outflow. However, this requires resternotomy with increased risk of wound and device infection, as well as excessive bleeding. We describe the use of peripheral venoarterial extracorporeal membrane oxygenation as a short-term treatment of right heart failure after HeartWare LVAD implantation.
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Peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) for acute cardiac failure reestablishes normal oxygen delivery and perfusion. However, VA ECMO can be limited by insufficient ventricular unloading, resulting in thrombus formation and pulmonary edema. Impella 2.5 has been used to unload the left ventricle and provide hemodynamic support during acute heart failure. ⋯ Five patients on VA ECMO with ventricular distension underwent Impella 2.5 implantation, resulting in a decreased left ventricular end-diastolic diameter as measured by echocardiography (7.8 ± 1.4 vs. 6.2 ± 0.8 cm, p = 0.001). Four patients were subsequently transitioned to the HeartMate II LVAD after restoration of end-organ function. Impella 2.5 is a safe means to unload the left ventricle while on peripheral VA ECMO to prevent left ventricle thrombus formation and worsening pulmonary edema in patients transitioning to a HeartMate II LVAD.