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Biomedical subjects

A Mohnhaupt

Publications and source records attributed to A Mohnhaupt.

9 recordsLinked to original sources
PubMed1991

The geriatric patient in surgery. Experience with patients over the age of 85 years.

Between 1982 and 1989 hospitalized treatment was applied to 615 patients aged between 85 and 101 years. The average age was 88.8 years. Operations were performed on 406 of them (66.1%). The surgical lethality amounted 16.5%. The lethality in conjunction with emergency operation was as high as 30.8% or as low as 10.7% in the context of elective operations. X-ray findings recorded from heart and lung as well as ECG provided reliable criteria for assessment of the surgical risk.

Age Factors↗
PubMed1988

[The elderly surgical patient. Experiences with patients over 85].

Hospitalised treatment was applied to 326 patients aged between 85 and 101 years, between 1982 and 1987. Operations were performed on 215 of them. The surgical lethality amounted to 16.3 per cent, though lethality in conjunction with emergency operations was as high as 23.9 per cent or as low as 11.8 per cent in the context of elective operations. X-ray findings recorded from heart and lung as well as ECG provided reliable criteria for assessment of the surgical risk.

Aged↗
PubMed1987

Design of a new pulse duplicator system for prosthetic heart valves.

This paper discusses results of a computer simulation for designing a new pulse duplicator system for mechanical heart valves. The design objective of the system is to obtain a compact, efficient pulse duplicator system capable of accurately measuring the volume flow rate across a valve. The volume flow rate is determined as the derivative of the volume displacement of an actuator piston which directly drives the fluid. The system does not need any circulatory loop, since the piston is controlled on-line to follow command signals representing an aortic impedance. The results of the computer simulation show: the designed PI-controllers of the actuator can precisely control valve motion to follow given command signals, the eigenvalues of the controllers have to be carefully chosen to prevent unstable behaviors of a valve in diastole, and the dimensions of the actuator is optimized by minimizing a cost function of the total efficiency of the system.

Biomechanical Phenomena↗
PubMed1976

[Controlling of artificial blood pumps after total heart replacement - an example of disregulation (author's transl)].

This is a report on the special regulation problem of the left blood pump after replacement of the natural heart by incorporated extracorporally driven blood pumps in an animal experiment. The consequence of the peripheral self-regulation on the transporting capacity of the bloodpumps considering the driving pressure and the systemic pressure losses has been investigated. Two possible controlling principles and the respective fields of application are discussed on the example of a lung oedema.

Animals↗
PubMed1976

[Observation in 10 calves with a survival time of more than 100 hours after total heart replacement (author's transl)].

It is reported on 10 calves surviving total artificial heart replacement more than 100 hours. Pneumatically driven double-chambered blood pumps made of silastic were implanted. During the experiments an increase of the right atrial pressure as well as a rise of the perfusion volumes (CO) and of the blood volumes could be found regularly. At autopsy congestion of the organs especially of the liver was a regular finding. The changed hemodynamic is first seen as possible reason for this developments. The influence of anemia and the possible disturbances in the neurohumoral autoregulation of the animals by unphysiologic pressure curves are discussed.

Animals↗
PubMedDate not supplied

Lifetime prolongation in voluntary alcohol-consuming rats (SHR) treated with clofibrate.

Clofibrate affects lipid and alcohol as well as drug and eicosanoid metabolism. Spontaneous hypertensive rats (SHR) further increase their high voluntary alcohol consumption during clofibrate feeding. The interaction of alcohol and clofibrate was studied in two long-term trials. Seventy-nine male SHR (aged 27 weeks) were offered increasing concentrations of ethanol, up to 30% (tap water ad lib), and 3 months later 0.5% clofibrate-food. Four groups were established: N, normal controls; NA, standard diet+alcohol; C, clofibrate feeding; and CA, clofibrate feeding + alcohol. Food intake, alcohol consumption, body weight, and laboratory values were recorded continuously. Life duration (weeks) after the start of the trial was 63.3 +/- 3.3 in N, 73 +/- 2.6 in NA, 77.7 +/- 4.3 in C, and 90.3 +/- 2.8 in CA. There were no alcohol-related liver findings in NA and CA. Most of the animals died of cardiac and renal failure. An increase of tumors in clofibrate-treated rats was not observed. Voluntary alcohol consumption or clofibrate feeding significantly lengthens lifetime, which is prolonged by 42% if ethanol is combined with clofibrate. This is obviously not mediated by the lipid lowering effect or an influence on body weight and blood pressure of either clofibrate or alcohol.

Alcohol Drinking↗