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Biomedical subjects

K Polzer

Publications and source records attributed to K Polzer.

At least 19 recordsLinked to original sources
PubMed1985

[Intraoperative changes in extravascular lung water. Study on heart surgery patients].

The intraoperative changes in extravascular lung water (EVLW) were studied in 40 patients undergoing aortic-coronary bypass grafting. The patients were divided into two groups on the basis of preoperative ejection fraction (EF) values (group I: EF greater than 45%; group II: EF less than 45%). EVLW was measured using the double-indicator dilution method (thermo/dye). In a control study, changes in transthoracic impedance (ZoTh) were recorded. The initial EVLW value in group I was 4.3 +/- 0.4 ml/kg body wt. and in group II, 4.4 +/- 0.3 ml/kg body wt. After extracorporeal circulation, significant changes in EVLW could be observed (group I: from 4.5 +/- 0.5 ml/kg body wt. to 7.0 +/- 0.2 ml/kg body wt.; group II: from 5.1 +/- 0.8 ml/kg body wt. to 7.8 +/- 0.9 ml/kg body wt. (p less than 0.001). At the end of the operation, no changes in EVLW were observed in group I. However, in group II EVLW was significantly different to initial values (6.3 +/- 1.0 ml/kg body wt., p less than 0.01). The results obtained using the double-indicator method were identical with those obtained using the transthoracic impedance method. A marked correlation could be seen between length of ECC recording and EVLW values at the end of the operation, especially when the ECC time was 90 min or more (r = 0.84). Based on our results, it must be assumed that intraoperative damage to capillary membranes occurs if the ECC time is above 90 min.

Coronary Artery Bypass↗
PubMed1984

[Control of spontaneous respiration with continuous positive airway pressure using transthoracic electrical impedance. Studies in subjects with healthy lungs].

A clinically practicable method for the control of intrapulmonary gas volume changes for patients with spontaneous respiration and CPAP has been evaluated. Changes of intrapulmonary gas volume caused by different continuous positive air-way pressures (CPAP) can be monitored sufficiently using a noninvasive technique of transthoracic electrical impedance (Z0). In 24 healthy volunteers Z0 (rheography) was measured. After stepwise increase of CPAP from 5-20 cm H2O a significant increase of Z0 could be observed. Z0 pressure relations, detected by regression analysis showed a correspondence of intrapulmonary gas filling changes and volume/pressure relation. We therefore conclude that the control of Z0 pressure relationship for the calculation of the maximum is of some importance for determination of therapeutic levels of CPAP.

Adult↗
PubMed1979

[Assessment of the cardiac output by impedance cardiography (differential rheography) to give optimum continuous positive pressure ventilation (author's transl)].

It is very important to know the cardiac output in artificial positive pressure ventilation for the determination of the exact dosage of dopamine and the endexpiratory pressure. Invasive monitoring of the cardiac output is not suitable for routine bedside use. In our study we looked into the question of whether the dosage of dopamine in continuous positive pressure ventilation could be controlled by impedance determination. Differential rheography, as described by Kaindl, Polzer, and Schuhfried, was used in the study. Relative changes in cardiac output after dopamine administration are shown with sufficient accuracy using the above-mentioned method.

Cardiac Output↗
PubMed1979

[The research programme "Artificial Heart" at the 2nd Department of Surgery, University of Vienna: a ten year review (author's transl)].

The experimental and clinical results are presented of the research programme "Artificial Heart" carried out by the 2nd Department of Surgery, University of Vienna. In particular, an assessment of the clinical experience in 177 patients with the intra-aortic balloon pump is documented and it is concluded that only limited cardiac support is possible by this pump. In view of this fact more efficient methods of mechanical circulatory support, such as the interaortic auxilliary ventricle, the aortic "Windkessel" ventricle with guiding balloon, and two types of ventriculo-aortic bypass ventricle were tested with regard to their haemodynamic and long-time efficacy. The transatrio-aortic auxilliary ventricle (E-LVAD) was also clinically tested in 11 patients. In conclusion the problems of total mechanical heart replacement are discussed.

Animals↗
PubMed1978

Clinical application of the ellipsoid left heart assist device.

The ellipsoid left heart assist device (E-LVAD) was implanted in eight patients suffering from intraoperative heart failure. It was not possible to remove these patients from extracorporeal circulation following an intracardiac procedure; therefore, implantation of the E-LVAD was performed during extracorporeal circulation. The inflow connector was pushed forward from a purse-string suture on the right superior pulmonary vein, across the mitral valve and into the left ventricle. The outflow connector was joined to the ascending aorta. In two patients, the artificial heart chamber was removed after complete recovery of the circulation; these patients, however, later died. In six other patients, untreatable right heart failure developed and these patients died with the pump in place. It is concluded, therefore, that the right heart must also be mechanically supported during postoperative heart failure.

Adult↗
PubMed1977

[Control of respiratory therapy by means of rheography (author's transl)].

Rheography measures changes in electrical conductivity. In measurements taken at the thorax it was appeared that the changes in conductivity caused by breathing are superimposed by the changes caused by circulatory factors and exceed them in amplitude quite far. This makes the expansion of rheography for electrical respiration control possible. The changes in electrical conductivity are explained by inspiration into the alveoles, by the increase in the distance of the electrodes on thoracic expansion, and by the change in the intrathoracic blood volume. When using respiratory therapy the physiotherapist must pay great attention how the patient reacts to respiratory therapy and whether he is adapted correctly to the mechanical respiratory support devices. The method of "rheospirography" was tested as to whether it allows an objective, direct evaluation of the interplay between respiratory therapy and patient. The method appears to be able to control respiratory therapeutic measures as it allows an evaluation of the respiratory type, the regional ventilation, and the adaption of the patient to the device.

Adult↗
PubMed1977

[Rheographic monitoring of lung ventilation (author's transl)].

Electrical conductivity changes are measured with rheography. Changes of conductivity on the thorax caused by respiration, superimpose and exceed those caused by different circulatory conditions. Therefore rheography was adapted for monitoring of respiration. Changes in electric conductivity can be explained by the inflow of air to the alveoli, by increase of the distance between electrode, and by changes of the intrathoracic blood volume. Rheography developed by Polzer and Schuhfried was tested in the intensive care unit and the respiration therapy department. It was shown that this method is suitable for control of respiration, for demonstrating regional differences of pulmonary ventilation, for checking of respiration therapy and for monitoring the ventilated patient.

Asthma↗
PubMed1976

[A new design for a totally artificial heart: the ellipsoid heart (author's transl)].

Thromboembolic complications represent the main limiting factor in cardiac replacement by totally artificial hearts in calves at present. Thrombus formation within artificial hearts is caused by the appearance of stagnation areas. The ellipsoid heart eliminates stagnation areas by virtue of its production as a one-piece membrane. The heart is driven pneumatically and functions as a diaphragmatic blood pump. The stroke volume is 178 cm3 and the maximal cardiac output 15.8l/Min. Three acute experiments demonstrated a high degree of haemodynamic efficiency without compression of, or interference with surrounding structures, especially the inferior vena cava or the right atrium.

Animals↗