Ventricular assist devices (VADs) are systems for mechanical circulatory support of the patient with severe heart failure. Perioperative transesophageal echocardiography is a major component of patient management, and important for surgical and anesthetic decision making. In this review we present the rationale and available data for a comprehensive echocardiographic assessment of patients receiving a VAD. In addition to the standard examination, device-specific pre-, intra-, and postoperative considerations are essential to the echocardiographic evaluation. These include: (a) the pre-VAD insertion examination of the heart and large vessels to exclude significant aortic regurgitation, tricuspid regurgitation, mitral stenosis, patent foramen ovale, or other cardiac abnormality that could lead to right-to-left shunt after left VAD placement, intracardiac thrombi, ventricular scars, pulmonic regurgitation, pulmonary hypertension, pulmonary embolism, and atherosclerotic disease in the ascending aorta; and to assess right ventricular function; and (b) the post-VAD insertion examination of the device and reassessment of the heart and large vessels. The examination of the device aims to confirm completeness of device and heart deairing, cannulas alignment and patency, and competency of device valves using two-dimensional, and color, continuous and pulsed wave Doppler modalities. The goal for the heart examination after implantation should be to exclude aortic regurgitation, or an uncovered right-to-left shunt; and to assess right ventricular function, left ventricular unloading, and the effect of device settings on global heart function. The variety of VAD models with different basic and operation principles requires specific echocardiographic assessment targeted to the characteristics of the implanted device.
A 3-day regimen of PHT prophylaxis is adequate to prevent seizures in subarachnoid hemorrhage patients. Drug reactions are significantly reduced, but seizure rates do not change. Short-term PHT administration may be a superior treatment paradigm.
Poly(D,L-lactic-co-glycolic acid) (PLGA) is an important material used in drug delivery when controlled release is required. The purpose of this research is to design and characterize PLGA microparticles (PLGA MPs) implants for the controlled release of nicardipine hydrochloride (NCH) in vitro. This study used the water-in-oil-in-water (w1/o/w2) double emulsion and solvent diffusion/evaporation approach to prepare PLGA MPs. Optimal processing conditions were found, such as polymer content, surfactant type, stabilizer concentration, inner and outer aqueous phase volumes, and stirring speed. The PLGA MPs for use as nicardipine hydrochloride (NCH) loading and release had spherical morphology, and the average diameter was smaller than 5.20 ± 0.25 μm. The release kinetics were modeled to elucidate the possible mechanism of drug release. In vitro release studies indicated that the NCH release rate is slow and continuous. PLGA MPs are an interesting alternative drug delivery system, especially for use with NCH for biomedical applications.
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