Transcatheter aortic valve replacement (TAVR) is a novel therapeutic intervention for the replacement of severely stenotic aortic valves in high-risk patients for standard surgical procedures. Since the initial PARTNER trial results, use of TAVR has been on the rise each year. New delivery methods and different valves have been developed and modified in order to promote the minimally invasive p...

BACKGROUND AND OBJECTIVE To evaluate the capability of first responders to ensure an airway and ventilate the lungs of a patient employing a bag-valve device and two oxygen-driven resuscitators. METHODS Prospective, controlled, blinded, single-centre clinical trial using a bag-valve device and one of two FR-300 devices, with 20 cmH2O working pressure, flows of 24 and 30 L min(-1). One-hundred...

8. What is the pathophysiology of mitral stenosis? Increased left atrial pressure is necessary to push blood through a stenotic mitral valve from the left atrium into the left ventricle. Increased left atrial pressure is transmitted retrograde into the pulmonary veins and pulmonary capillaries and ultimately into the pulmonary arteries. It gives the patient a sensation of dyspnea. A left atrial...

An automated, pre-programmed, multiplexed hydraulic valve actuator is described. The valve is membrane-based and normally open. In contrast to the membrane-based pneumatic valve, the hydraulic valve uses hydraulic liquid to exert the control pressure. The line pressure is controlled with a roller moving over a prefabricated topology. Multiple rollers, each traversing its own track, are assemble...

As a result of the durability problems associated with the first Abrams-Lucas mitral valve, a redesigned model has recently been introduced into limited clinical trials. The new valve was subjected to in-vitro pulsatile flow studies, and measurements were made of mean diastolic pressure gradient and volume of reflux on closure. Similar measurements were made on other mitral valve prostheses of ...

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the ...

PCCI engines can reduce NOx and PM emissions simultaneously without sacrificing thermal efficiency, but a low combustion temperature resulting from early fuel injection, and ignition occurring prior to TDC, can cause higher THC and CO emissions and fuel consumption. In conclusion, it was found that the PCCI combustion achieved by the 2-stage injection strategy with optimized calibration factors...

errors in blood pressure (bp) measurement are common in the clinical practice. inaccurate measurements of bp may lead to misdiagnosis and inappropriate treatment of hypertension. the preferred method of bp measurement in the clinical setting is a scultation, using the first and the fi fth korotkoff sounds. however, the use of mercury sphygmomanometer is declining. automated oscillometric device...

THE experimental production of sudden, severe aortic insufficiency causes left ven-tricular diastolic pressure to become markedly elevated so that it exceeds left atrial pressure and results in diastolic closure of the mitral valve.' Ten cases of severe aortic insuffi-ciency have been reported in which left ven-tricular pressure exceeded left atrial pressure during diastole, causing premature m...

The physiologic correlates of ejection sounds have been studied by simultaneous phonocardiograms, echocardiograms and high fidelity pressure tracings. Ejection sounds associated with semilunar valve stenosis or hypertension of the systemic or pulmonary circulation occur at the moment of complete opening of the aortic or pulmonary valve recorded echocardiographically. The start of opening of the...