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.
Summary. Eighteen calves (weight: 100 + 30 kg) with a total artificial heart are ventilated by a Bennett MA-IB respirator. The atelectasis of the lung seems to be the most important complication in the respiratory system. The static thoraxlung-"compliance" decreases relatively more d~ring HLYf-perfusion than during TAH-perfusion. The tidal volume of 11 _+ 3 × 10 ~ ml, combined with a frequency of 10/rain leads to a breathing pressure of 20 to 30 cm H20. Humidified, warm gases, PEEP-(6 to 8 cm H2) and SIGH-ventilation are applied. The oxygen concentration of the inspired gas is kept as low as possible. Generally this ventilation technique provides a normal arterial oxygen saturation. Four animals substituted by 02-insufflation breathed spontaneously, maximal t00 h. Several changes of blood pressure in the artificial heart, the pulmonary artery and the aorta depend on the phase of ventilation, which may be influenced by a change of artificial heart's position and of the lung-vessels' capacity.Key words: Total Artificial Heart Replacement --Ventilation --Blood Gases --Blood Pressure.Zusammen/assung. 18 K~lber (KSrpergewicht = 100 _+ 20 kg) mit einem kfinstlichen Totalherzen werden mit einem Bennett MA-tB Respirator beatmet. Unter den prim/iren pulmonalen Komplikationen wird der Lungenatelektase eine vorrangige Bedeutung beigemessen. Die statische Thorax-Lungen-,,Compliance" nimmt deutlich unter der Perfusion mit der Herz-Lungenmaschine und weniger deutlich unter der des kiinstlichen Totalherzens ab. Bei einem Atemzugvolumen yon II + 3 × 10 ~ ml und einer Atemfrequenz yon 10/rain kommen Beatmungsdrucke yon 20 bis 30 cm H20 zustande. Dabei werden m6glichst niedrige Sauerstoffkonzentrationen in der Inspirationsluft angestrebt. Es wird mit feuchtwarmer Luft positiv-endexspiratorischen Drucken yon 6--8 cm H20 und SIGH beatmet. Diese Beatmungstechnik gew£hrleistet auch in kritischen Versuchsphasen eine normale arterielle Sauerstoffs/ittigung. Bei vier Versuchstieren war eine Spontanatmung unter Sauerstoffinsufflation fiber eine Nasensonde bis maximal 100 Std m6glich. In Abh/ingigkeit yon der in-und exspiratorischen Beatmungsphase werden Druckschwankungen im kiinstlichen Totalherzen sowie in der Arteria pulmonalis und in der Aorta infolge yon Anderungen erstens der Lage des kfinstlichen Totalherzens und zweitens der Lungengef~Bkapazit/it analysiert.
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