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Cardiorespiratory interactions in patients with an artificial heart.
J L Robotham1, J B Mays, M A Williams
1Department of Anesthesiology and Critical Care, Johns Hopkins Hospital, Baltimore, Maryland 21205.
Anesthesiology
|October 1, 1990
Summary
Respiration significantly impacts artificial heart function, altering blood flow dynamics. Unlike natural hearts, artificial hearts experience unique pressure changes affecting ventricular filling and emptying.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
Background:
- Artificial hearts (total artificial hearts, TAH) are mechanical circulatory support devices.
- Understanding the physiological interactions between TAH and the respiratory system is crucial for patient management.
Purpose of the Study:
- To analyze the influence of respiration on the performance of TAH in patients.
- To compare the mechanisms of respiratory-induced ventricular changes in TAH recipients versus healthy individuals.
Main Methods:
- Retrospective analysis of three patients with TAH.
- Monitoring of systemic arterial pressure and intrathoracic pressure during spontaneous ventilation.
Main Results:
- Spontaneous ventilation caused significant intrathoracic pressure swings, mimicking pulsus paradoxus in systemic arterial pressure.
- Decreased intrathoracic pressure reduced biventricular filling but enhanced emptying.
- Increased intrathoracic pressure augmented biventricular filling but impeded emptying due to increased afterload.
Conclusions:
- Respiration influences TAH performance through pressure gradients, with artificial ventricles acting as extrathoracic pumps.
- The mechanisms differ from native hearts due to the extrathoracic location and lack of a compliant septum.