Search PubMed⌕ Search

Biomedical subjects

E Gornik

Publications and source records attributed to E Gornik.

42 records · Page 3Linked to original sources
PubMed1985

Hydraulic driving unit and control system for artificial hearts.

A driving unit for artificial ventricles was constructed in which the power transmission is hydraulic. This avoids the danger of an air embolism, which is characteristic of pneumatic drives in the case of membrane rupture. An electromagnet as a power source drives a rolling membrane pump to move the transmission fluid to the artificial ventricle. This incompressible connection allows direct control of membrane motion and pumped blood volume simply by measuring the armature stroke. The volume-controlled mode is characterized by automatic self-regulation according to Starling's law and self-synchronization when the drive is used as a left (or right) ventricular assist device. Several measures were taken to increase the operational safety. The hemodynamic efficiency of the drive was tested in a number of in vivo experiments. The long-term stability was proven in a 12-month durability test.

Animals↗
PubMed1984

[Use of an improved simultaneous film cassette in linear tomography].

An improved simultaneous tomography cassette according to P. Landau was tried out for four months using four tomographs in routine work. The mode of operation is based on accurate control of the relative speeds of the individual x-ray films resulting in simultaneous imaging of 6 equidistant tomographic levels. Clinical testing was effected in 80 cases: nephrotomography, of the lungs, the hilum, and the skeleton. In particular, the article describes imaging of the renal arteries by simultaneous tomography for the purpose of finding out the cause of hypertension, and if there is suspicion of a space-occupying growth in the kidney, basing on the urogram. The specific advantages of this technique are, on the one hand, improved diagnostic efficiency (the tomograms are taken during the same respiratory phase, more rapid diagnosis especially with accident patients), and, on the other hand, an important reduction in the x-ray exposure of the patient; furthermore, the life of the x-ray tube is prolonged, and there is a definite saving of time for both patient and personnel, the image quality being comparable with that of single-layer tomography.

Aortic Diseases↗
PubMedDate not supplied

A new hydraulic heart assist device.

For the right drive of a hydraulic biventricular assist device (HBVAD), a new lightweight magnet with a permanent magnetic armature was constructed. A miniature optically incremental position sensor was developed, which is an integral part of the control loop of the driving unit, and was incorporated in the armature. Mock circulation tests proved the stability of the drive and showed the expected sensitivity to the preload pressure. In vivo experiments in calves were carried out in order to test its haemodynamic efficiency on a beating and on a fibrillating heart, and to test the mutual interaction of the left and right hydraulic assist devices (LVAD, RVAD) via the vascular system. Both drives were controlled independently, operating in the volume-controlled mode. For the modelling of a heart disease, the heart was blocked by the administration of verapamil (Isoptin). It could be shown that the HBVAD is able to maintain the circulation. Various tests with the left and/or right drive active showed distinct unloading effects for the natural heart and proved the mutual interaction of both drives via the vascular system. An inherent feature of the hydraulic drive system is its ability to be triggered by a (weakly) beating heart. The preload sensitivity of the HBVAD was tested by the administration of adrenaline. Similar reactions of the drives resulted for a beating and for a fibrillating heart, showing the regulation characteristic according to Starling's law.

Animals↗