Central venous pressure and cardiac function during spaceflight
Autor: | C. Gunnar Blomqvist, Ronald J. White |
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Rok vydání: | 1998 |
Předmět: |
Cardiac function curve
Pulmonary Circulation Frank–Starling law of the heart Cardiac output Central Venous Pressure Weightlessness Physiology business.industry Central venous pressure Hemodynamics Blood Pressure Heart Stroke Volume Intrapleural pressure Stroke volume Space Flight Models Biological Blood pressure Physiology (medical) Anesthesia Humans Medicine Cardiac Output business |
Zdroj: | Journal of Applied Physiology. 85:738-746 |
ISSN: | 1522-1601 8750-7587 |
Popis: | Early in spaceflight, an apparently paradoxical condition occurs in which, despite an externally visible headward fluid shift, measured central venous pressure is lower but stroke volume and cardiac output are higher, and heart rate is unchanged from reference measurements made before flight. This paper presents a set of studies in which a simple three-compartment, steady-state model of cardiovascular function is used, providing insight into the contributions made by the major mechanisms that could be responsible for these events. On the basis of these studies, we conclude that, during weightless spaceflight, the chest relaxes with a concomitant shape change that increases the volume of the closed chest cavity. This leads to a decrease in intrapleural pressure, ultimately causing a shift of blood into the vessels of the chest, increasing the transmural filling pressure of the heart, and decreasing the central venous pressure. The increase in the transmural filling pressure of the heart is responsible, through a Starling-type mechanism, for the observed increases in heart size, left ventricular end-diastolic volume, stroke volume, and cardiac output. |
Databáze: | OpenAIRE |
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