Long-duration +Gz acceleration on cardiac volumes determined by two-dimensional echocardiography.
J Clin Pharmacol
; 34(5): 484-8, 1994 May.
Article
em En
| MEDLINE
| ID: mdl-8089260
ABSTRACT
To enhance protection of humans exposed to long-duration low-gravity environments such as the Space Shuttle and National Aerospace Plane during re-entry or in the short-duration high(-)+Gz environment of fighter aircraft, the effects of +Gz acceleration on cardiovascular hemodynamics must be understood. This study reports the use of two-dimensional echocardiography in normal men during +Gz acceleration. The heart's position in relation to the chest did not change during acceleration up to +7 Gz. The success in maintaining high-quality images during exposures to G-forces of this magnitude may be attributed to the relatively low rate of G onset. End-diastolic volumes (EDV) and stroke volumes (SV) decreased during a +Gz acceleration ramp that increased until the subject experienced peripheral light loss (PLL) (P < .05). An inflated G-suit partially counteracted this effect. By 30 seconds of a +3 Gz acceleration plateau, the protective effects of the inflated G-suit to maintain EDV is lost and the EDV of the inflated G-suit was lower than the EDV of the uninflated G-suit (P < .05).
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Base de dados:
MEDLINE
Assunto principal:
Volume Sistólico
/
Aceleração
/
Gravitação
/
Hemodinâmica
Limite:
Adult
/
Humans
/
Male
Idioma:
En
Revista:
J Clin Pharmacol
Ano de publicação:
1994
Tipo de documento:
Article