Central Venous Access System

A catheter system and method of use for re-establishing venous access near an occluded vessel

Experimental investigation of scattering from randomly rough elastic cylinders

Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1992Acoustical backscattering from randomly rough infinitely long elastic cylinders surrounded by a fluid medium is examined. The cylinder radius is allowed to vary along its lengthwise axis creating one-dimensional rotationally symmetric roughness. Using recently published rough cylinder formulations [T.K. Stanton, J. Acoust. Soc. Am., 92, 1641-1664 (1992) and T.K. Stanton and D. Chu, J. Acoust. Soc. Am., 92, 1665-1678 (1992)], explicit expressions are derived for the backscattered field for a laboratory pulse-echo environment: spherically spreading directional source and receiver with arbitrary beam patterns. Efficient numerical integration algorithms are developed to solve for the backscattered field from a specified surface profile. Experimental measurements from dense elastic (stainless steel) cylinders immersed in water are presented to quantitatively illustrate the effects of small scale surface roughness (δs/a = 0.0131 where δ is the surface rms roughness and a is the mean cylinder radius) for 4.5 < ka < 70 where k is the acoustic wavenumber. The actual target surface profile is well described and used as an input in the numerical simulations. Agreement is found between measurements and simulation predictions both in the mean field levels and the field fluctuations over a wide range of frequencies

Flexible Recording/High Energy Electrode Catheter with Anchor for Ablation of Atrial Flutter by Radio Frequency Energy

An electrode catheter is provided having a predetermined flexibility throughout the entire length or at least at the contact portion, such as the electrode region, to allow for the molding of the contact portion such that it conforms to the shape of the heart at a preselected desired target area, such as the isthmus between the inlet of inferior vena cava and posterior tricuspid annulus. The catheter also includes a guiding sheath that is preferably semirigid and may be pre-shaped with at least one bend or angulation to assist in molding to ensure that the electrode region overlies the desired target treatment area. A remotely controlled anchoring device is provided at the distal end of the catheter for anchoring it in position to facilitate the molding operation and placement over the target treatment area. A method of cardiac ablation using the catheter of the present invention is also disclosed

O excesso de liquidez e as reformas monetárias européias - 1944-52

The authoi describes, classifles, and evaluates 24 cases of monetary reforms in post-war Europe. Reforms of type one consisted in the compulsory exchange of existing liquíd assets for new notes at variable rates o f exchanges, a process which reduced liquidity. Reforms of type two used the technique of a tempotary blocking of liquid assets, also resulting in liquidity-squeeze. Reforms of type three were a combination of the two prevíous cases. The first type was mainly used in countries under the Soviet orbít while the second, the most frequent, was applied mostly in Western countries. General results conceming their antí-inflationary aims and other objectives are analysed

Left Atrial Veno-Arterial Extracorporeal Membrane Oxygenation (LAVA-ECMO): Percutaneous Bi-Atrial Drainage to Avoid Pulmonary Edema in a Patient with Left Ventricular Systolic Dysfunction

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is used in patients with severe cardiogenic shock refractory to medical therapy. During V-A ECMO, retrograde flow in the aorta towards the left ventricle (LV) causes increased left-sided filling pressures, which may lead to pulmonary edema. Different strategies have been proposed to decompress the left heart, including placement of an intraaortic balloon pump (IABP), Impella® (Abiomed), or TandemHeart® (Cardiac Assist). Percutaneous decompression of the left atrium via placement of a transseptal cannula incorporated into the existing venous limb had also been previously done. We describe the novel use of the VFEM venous femoral cannula (Edwards Lifesciences) placed transseptally in a left atrial, veno-arterial (LAVA) configuration to provide simultaneous bi-atrial drainage in a patient on V-A ECMO due to cardiogenic shock

Snaring of the Right Ventricular Lead During Cavotricuspid Isthmus Ablation

The presence of a right ventricular (RV) lead may interfere with cavotricuspid isthmus (CTI) ablation. We present a new option of lifting the RV lead from the CTI allowing a successful ablation of a CTI-dependent flutter without compromising lead integrity and functionality

High Hepatitis E Seroprevalence Among Displaced Persons in South Sudan.

AbstractLarge protracted outbreaks of hepatitis E virus (HEV) have been documented in displaced populations in Africa over the past decade though data are limited outside these exceptional settings. Serological studies can provide insights useful for improving surveillance and disease control. We conducted an age-stratified serological survey using samples previously collected for another research study from 206 residents of an internally displaced person camp in Juba, South Sudan. We tested serum for anti-HEV antibodies (IgM and IgG) and estimated the prevalence of recent and historical exposure to the virus. Using data on individuals' serostatus, camp arrival date, and state of origin, we used catalytic transmission models to estimate the relative risk of HEV infection in the camp compared with that in the participants' home states. The age-adjusted seroprevalence of anti-HEV IgG was 71% (95% confidence interval = 63-78), and 4% had evidence of recent exposure (IgM). We estimated HEV exposure rates to be more than 2-fold (hazard ratio = 2.3, 95% credible interval = 0.3-5.8) higher in the camp than in the participants' home states, although this difference was not statistically significant. HEV transmission may be higher than previously appreciated, even in the absence of reported cases. Improved surveillance in similar settings is needed to understand the burden of disease and minimize epidemic impact through early detection and response