Technology and Health Care - Volume 2, issue 3

Authors: Lunkenheimer, P.P. | Redmann, K. | Cryer, C.W. | Richter, K.-D. | Niederer, P. | Whimster, W.F. | Torrent-Guasp, F.

Article Type: Research Article

Abstract: The literature on the morphology of the heart is reviewed within the context of recent histological findings. There is strong evidence for a dualistic myocardial function, whereby both ventricular constricting and expanding forces are supposed to act synchronously although with variable effect over the heart cycle. The morphological basis of this dualistic myocardial function is the contorted rope-like structure worn into the bulk of the heart muscle. Opinions are divided about the invasiveness of blunt preparation on the heat denatured heart by which the fascicular architecture is carved out of the muscle. Histology confirms the existence of a fascicular …substructure. It results from an inhomogeneous repartition of myocardial fibre branchings and the arrangement of the delicate connective tissue netting by which myocardial strands are bundled and wrapped. One important feature of the fascicular structure of the heart muscle is an oblique transmurally arranged element which yields a force vector opposing systolic wall thickening. This structural element which acts in the direction of ventricular dilation probably gains pathological import in some cases of architectural remodelling, namely in myocardial fibrosis and hypertrophy. Show more

Keywords: Fascicular structure of myocardium, heart, heat deanatured, Blunt preparation, Rope structure, Fibre alignment, Cleavage plane, Freedom of motion, Compartmentation, Wall stress

DOI: 10.3233/THC-1994-2301

Citation: Technology and Health Care, vol. 2, no. 3, pp. 155-173, 1994

Authors: Guttmann, Josef | Eberhard, Luc | Fabry, Ben | Zappe, Detlef | Bernhard, Holger | Lichtwarck-Aschoff, Michael | Adolph, Michael | Wolff, Gunther

Article Type: Research Article

Abstract: In patients mechanically ventilated for severe respiratory failure, respiratory system mechanics are non-linear, i.e., volume-dependent. We present a new computer-based multipoint method for simultaneously determining volume-dependent dynamic compliance and resistance. Our method is based on continuously determined tracheal pressure (Ptrach ). Tidal volume is subdivided into six volume slices of equal size. One compliance value (intrinsic PEEP considered) and one resistance value are determined for each volume slice by applying of the least-squares-fit (LSF) analysis based on the linear RC-model; we therefore call this the SLICE method. The method gives the course of dynamic compliance and resistance within the tidal …volume. The method was evaluated using physical models of the respiratory system with linear and non-linear passive mechanical properties. The relative error of the method is smaller than ±5%. The method needs no special ventilatory pattern. Using data from 14 patients mechanically ventilated for adult respiratory distress syndrome (ARDS) we found a very good correspondence between the measured end-inspiratory airway pressure (Paw,Ie ) and the end-inspiratory alveolar pressure (Palv,Ie ) calculated from the dynamic compliance values determined with the SLICE method (Palv,Ie = 1.02 * Paw,Ie + 0.097; r2 = 0.977). The SLICE method allows continuous monitoring of non-linear pulmonary mechanics on a breath-by-breath basis at the bedside. Show more

Keywords: Dynamic compliance, Dynamic resistance, Non-linear mechanics, Mechanical ventilation

DOI: 10.3233/THC-1994-2302

Citation: Technology and Health Care, vol. 2, no. 3, pp. 175-191, 1994

Authors: Krebs, M. | Gallo, L.M. | Airoldi, R.L. | Meier, D. | Boesiger, P. | Palla, S.

Article Type: Research Article

Abstract: The aim of this investigation was to develop a method to reconstruct three-dimensionally the temporomandibular joint (TMJ) by means of magnetic resonance (MR) tomograms and to combine this reconstruction with jaw motion data, recorded with six degrees of freedom by means of the opto-electronic system Jaws-3D, in order to analyse the movement of the whole condyle within the fossa during opening and closing, protrusive and laterotrusive movements. The three-dimensional reconstruction of the TMJ was calculated and animated on a graphics workstation. The condyle – fossa distance during jaw movements was computed for every condylar point and visualized by shading the …surface of the condyle with pseudo colors. Furthermore, the location of the minimum condyle–fossa distance was calculated and displayed in a plane graph representing the condylar surface. For five subjects without any past or present history of myoarthropathies of the masticatory system the resulting patterns were analyzed and compared. Show more

Keywords: Temporomandibular joint, Biomechanics, Condylar movements, Magnetic resonance imaging, 3D image analysis

DOI: 10.3233/THC-1994-2303

Citation: Technology and Health Care, vol. 2, no. 3, pp. 193-207, 1994

Authors: Tsalpatouros, A. | Panou-Diamandi, O. | Papageorgiou, Ch. | Rambavillas, A. | Stefanis, C. | Uzunoglu, N. | Koutsouris, D.

Article Type: Research Article

Abstract: The latest progress in the area of psychophysiology and psychopathology has urged the need for new tools, being able to perform special, non-invasive measurements. By measuring the eye pupil diameter and its variations, new and interesting conclusions can be reached, concerning the effect of specific drugs on humans or the process of reaction to certain stimuli with psychophysiological significance. We present the design, the development, the integration and the evaluation of a new system for the measurement of the eye pupil diameter and its variations as a function of time. The main advantages are a low cost system based …on a personal computer and the introduction of some new algorithmic techniques on manipulating eye images. Show more

DOI: 10.3233/THC-1994-2304

Citation: Technology and Health Care, vol. 2, no. 3, pp. 209-213, 1994