Orthostatic intolerance after spaceflight.

Buckey, J C; Lane, L D; Levine, B D; Watenpaugh, D E; Wright, S J; Moore, W E; Gaffney, F A; Blomqvist, C G

Buckey, J C; Lane, L D; Levine, B D; Watenpaugh, D E; Wright, S J; Moore, W E; Gaffney, F A; Blomqvist, C G.

Afiliación

Buckey JC; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235-9034, USA.

J Appl Physiol (1985) ; 81(1): 7-18, 1996 Jul.

Article en En | MEDLINE | ID: mdl-8828642

RESUMEN

Orthostatic intolerance occurs commonly after spaceflight, and important aspects of the underlying mechanisms remain unclear. We studied 14 individuals supine and standing before and after three space shuttle missions of 9-14 days. After spaceflight, 9 of the 14 (64%) crew members could not complete a 10-min stand test that all completed preflight. Pre- and postflight supine hemodynamics were similar in both groups except for slightly higher systolic and mean arterial pressures preflight in the finishers [15 +/- 3.7 and 8 +/- 1.2 (SE) mmHg, respectively; P < 0.05]. Postflight, finishers and nonfinishers had equally large postural reductions in stroke volume (-47 +/- 3.7 and -48 +/- 3.3 ml, respectively) and increases in heart rate (35 +/- 6.6 and 51 +/- 5.2 beats/min, respectively). Cardiac output during standing was also similar (3.6 +/- 0.4 and 4.1 +/- 0.3 l/min, respectively). However, the finishers had a greater postflight vasoconstrictor response with higher total peripheral resistance during standing (22.3 +/- 1.2 units preflight and 29.4 +/- 2.3 units postflight) than did the nonfinishers (20.1 +/- 1.1 units preflight and 19.9 +/- 1.4 units postflight). We conclude that 1) the primary systemic hemodynamic event, i.e., the postural decrease in stroke volume, was similar in finishers and nonfinishers and 2) the heart rate response and cardiac output during standing were not significantly different, but 3) the postural vasoconstrictor response was significantly greater among the finishers (P < 0.01).

Asunto(s)

Hipotensión Ortostática/fisiopatología; Vuelo Espacial; Ingravidez/efectos adversos; Adulto; Barorreflejo/fisiología; Femenino; Frecuencia Cardíaca/fisiología; Humanos; Pierna/anatomía & histología; Pierna/irrigación sanguínea; Masculino; Persona de Mediana Edad; Consumo de Oxígeno/fisiología; Postura/fisiología; Flujo Sanguíneo Regional/fisiología; Volumen Sistólico/fisiología; Resistencia Vascular/fisiología; Vasoconstricción/fisiología

Palabras clave

NASA Discipline Cardiopulmonary; NASA Discipline Number 00-00; NASA Discipline Number 14-10; NASA Discipline Number 93-10; NASA Program Flight; NASA Program NSCORT; NASA Program Space Physiology and Countermeasures; Non-NASA Center

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Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Vuelo Espacial / Ingravidez / Hipotensión Ortostática Límite: Adult / Female / Humans / Male / Middle aged Idioma: En Revista: J Appl Physiol (1985) Asunto de la revista: FISIOLOGIA Año: 1996 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos

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