ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Echocardiography is the standard to assess heart function although obtaining transesophageal echocardiography (TEE) on an emergent basis may be limited by its availability. A transoral miniaturized hemodynamic TEE (hTEE) probe (ImaCor Inc.) was developed to provide direct visualization of the heart, and we hypothesized that the probe could provide hemodynamic information useful for patient management. Data from 2011 to 2012 was retrospectively collected. ⋯ The indications for probe insertion were hemodynamic instability (n = 32), ECMO weaning (n = 10), VAD alarm (n = 1), tamponade (n = 14), pulmonary embolism (n = 2), and intra-aortic balloon pump wean (n = 2). In all 61 cases, we were successfully able to diagnose and treat the etiology of instability based on the hTEE findings. Utilization of the hTEE probe successfully diagnosed and aided therapy in all patients with hemodynamic instability refractory to initial therapy and provides a valuable tool to aid clinicians in the management of postoperative hemodynamics.
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Patients on extracorporeal membrane oxygenation (ECMO) are critically ill, and fluid balance need to be managed as accurately as possible. Previous studies have focused on insensible water loss through neonatal ECMO circuit and showed that water loss through the ECMO circuit was correlated with the sweep-gas flow rates. Current study is the first study focusing on insensible water loss through adult ECMO circuit. ⋯ The amount of water loss through the ECMO circuit was found to be linearly correlated with the sweep-gas flow rate and fluid temperature. For every liter per minute of sweep-gas flow at 37°C, 0.046 ml/min of water will be lost, and for every change of fluid temperature by 1°C, water content loss will be changed by 0.0026 ml/min by multiple linear regression (R = 0.996). The average daily water loss for every liter per minute of sweep-gas flow at 33, 34, 35, 36, 37, 38, and 39°C were 51.3, 55, 58.8, 62.5, 66.2, 70.0, and 73.7 ml/day, respectively.
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Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. ⋯ Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.
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Extracorporeal membrane oxygenation (ECMO) is a salvage therapy in acute cardiac failure and/or severe respiratory failure. In this case report the importance of cannula positioning during veno-venous ECMO is exemplified. The use of echocardiography and its advantages compared to plain chest radiograph will be shown. ⋯ Echocardiography was used to optimize the cannula position, and thus, rapidly improving the patient's oxygenation. A persistent left superior vena cava and its effect on the central hemodynamics were also objectified. This case illustrates important considerations in daily ECMO treatment: the benefit of direct echocardiographic competence at all times during the day, the importance of understanding central blood flow dynamics, to adjust the cannula-position accordingly, and to address situations outside the ordinary with a physiologic approach.
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Case Reports
Prolonged use of extracorporeal membrane oxygenation as a rescue modality following traumatic brain injury.
A 21-year-old male trauma patient presented after a motor vehicle crash, witnessed massive aspiration and sustained traumatic brain injury. On postinjury day 3, the patient progressed to adult respiratory distress syndrome (ARDS) refractory to all conventional therapies, prompting the use of extracorporeal membrane oxygenation (ECMO). ⋯ The patient is currently home without any neurological deficits. Although controversial, ECMO may serve a role as a rescue therapy in ARDS when conventional therapies fail in the brain-injured patient.