Ultrasonographic finding of internal jugular vein during anti-G straining maneuver: is it associated with gravity-induced loss of consciousness?
Eur J Appl Physiol
; 109(4): 625-30, 2010 Jul.
Article
em En
| MEDLINE
| ID: mdl-20186423
ABSTRACT
Gravity-induced loss of consciousness (G-LOC) is caused by loss of cerebral blood flow during high +Gz (head-to-foot inertial forces). The resistance of the jugular vein is a significant factor in decrease in cerebral blood flow. Ultrasonography of thoracic inlet veins, including internal jugular vein, is feasible to visualize the internal jugular vein and hemodynamic information. Anti-gravity straining maneuver (AGSM) was widely recognized as one of the important factors in preventing G-LOC. The purpose of this study was to evaluate the relationship between the ultrasonographic shape and size of internal jugular vein during AGSM and G-LOC. 47 trainee pilots who participated in human centrifuge education program were enrolled. They were all men, and their mean age was 23.9 +/- 1.38 years. Questionnaire sheets were used to collect information about well-being sensation, smoking, drinking, height, and weight. Using ultrasonography, we monitored shape and size of internal jugular vein during AGSM. After ultrasonographic examination, 47 subjects underwent human centrifuge on the same day. The protocol of human centrifuge training was maximal 6G with sustaining time of 30 s. G-LOC occurred to ten out of 47 subjects in human centrifuge. To find presumptive variable associated with G-LOC, we performed logistic regression analysis. Concave contour and smaller cross-sectional area of internal jugular vein during AGSM were associated with G-LOC.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Inconsciência
/
Mecânica Respiratória
/
Gravidade Alterada
/
Veias Jugulares
Tipo de estudo:
Diagnostic_studies
/
Etiology_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Adult
/
Humans
/
Male
País/Região como assunto:
Asia
Idioma:
En
Revista:
Eur J Appl Physiol
Ano de publicação:
2010
Tipo de documento:
Article