[Fiber optic sensor technology in the endotracheal tube].

The measurement of individual respiratory parameters in the vicinity of the lungs remains an unresolved problem in the areas of anesthesia and intensive care medicine. New technologies such as fibreoptic technology, which meet the extreme demands of medical sensor applications, and their innovative potential as a basis for the development of marketable products, appear promising. This is illustrated by the fundamental principles developed for a sensor-armed tracheal tube for on-line monitoring of ventilated patients.

New echocardiographic and angiographic methods for right atrial volume determination: in vitro validation and in vivo results.

Until now, right atrial (RA) volume calculation by means of two-dimensional echocardiography (2-DE) has only been attempted in a single plane: the apical four-chamber view. Our study reports a new method for RA volume calculation using two intersecting 2-DE views. For this purpose, silicone rubber casts of 19 human necropsy hearts were obtained and thin-walled natural rubber moulds of the RA casts were prepared.

Hydrodynamic investigation of mechanical bileaflet valves.

For hydrodynamic comparison, 11 mechanical bileaflet valves have been perfused in a mock circulation system under pulsatile flow conditions. Six St. Jude Medical valves with different sizes from No.

[Comparative study of mechanical heart valves for implantation in mitral position].

For hydrodynamic comparison of mechanical heart valves, three tilting disc valves (Björk-Shiley SD, Björk-Shiley CCD, Björk-Shiley Monostrut) and two bileaflet valves (St. Jude Medical, Duromedics) with annulus diameter dA = 31 mm were perfused in a mock circulation in mitral position. Flow, pressure, and orifice area were measured during pulsatile flow.

Results of a comparative in vitro study of Duromedics and Björk-Shiley monostrut mitral heart valve prostheses.

Two different mechanical heart valves with annulus diameters 21-29 mm, (five Björk-Shiley monostrut tilting disc valves and five Duromedics bileaflet valves) have been tested in pulsatile flow in the mitral position of a mock circulation. Reflux, pressure, and orifice area have been measured while cardiac output was varied between 2 and 6 1 min-1. Insufficiency, mean orifice area, discharge coefficient, and performance and efficiency indices have been calculated.

[A new echocardiographic procedure for calculation of the accurate volume of the right atrium].

The right atrial (RA) volume can be determined angiographically from two perpendicular projections. Up to now volume calculations by means of two-dimensional echocardiography (2-DE) have only been attempted in a single plane, the apical four-chamber view. Our study reports a new method for RA volume calculation using two intersecting cross-sectional echocardiographic views.

Hydrodynamic test of bioprostheses in the mitral position.

With the described circulation simulator it is possible to simulate physiological values of pulse frequency, filling volume and pressure. Bioprostheses with pathological changes can be investigated in vitro under normal and under specific pathological in vivo circulation conditions. The criteria of classification of the effectiveness of bioprostheses are reflux volume, VR, insufficiency, I and maximal orifice area, A.