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Titolo:
A mathematical model of cerebral perfusion subjected to Gz acceleration
Autore:
Cirovic, S; Walsh, C; Fraser, WD;
Indirizzi:
Def & Civil Inst Environm Med, N York, ON M3M 3B9, Canada Def & Civil InstEnvironm Med N York ON Canada M3M 3B9 ON M3M 3B9, Canada Univ Toronto, Inst Aerosp Studies, Downsview, ON, Canada Univ Toronto Downsview ON Canada t Aerosp Studies, Downsview, ON, Canada Ryerson Polytech Univ, Dept Mech Engn, Toronto, ON, Canada Ryerson Polytech Univ Toronto ON Canada t Mech Engn, Toronto, ON, Canada
Titolo Testata:
AVIATION SPACE AND ENVIRONMENTAL MEDICINE
fascicolo: 5, volume: 71, anno: 2000,
pagine: 514 - 521
SICI:
0095-6562(200005)71:5<514:AMMOCP>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
CIRCULATION; PRESSURE; SIMULATION; FLOW; HEAD;
Keywords:
vascular resistance; venous resistance; transmural pressure; tube law; perfusion pressure; cerebrospinal fluid; cerebrospinal fluid pressure;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Cirovic, S Def & Civil Inst Environm Med, 1133 Sheppard Ave W,POB 2000, N York, ON M3M 3B9, Canada Def & Civil Inst Environm Med 1133 Sheppard Ave W,POB 2000 N York ON Canada M3M 3B9
Citazione:
S. Cirovic et al., "A mathematical model of cerebral perfusion subjected to Gz acceleration", AVIAT SP EN, 71(5), 2000, pp. 514-521

Abstract

Background: When the human body is exposed to a high gravitational load, the blood supply to the brain is reduced and lass of consciousness may occur. Our goal is to identify the principal mechanical causes of reduced blood supply to the brain during high +Gz. Methods: We have developed a mathematical model to investigate the influence of Gz on the cerebral circulation. Blood flow is modeled using a one-dimensional flow approximation, in which the cross-sectional area of elastic vessels is determined as a non-linear function of the transmural (blood minus external) pressure. The intracranial vessels are subjected to cerebrospinal fluid pressure (PCSF) which is determined from the condition that the cranial volume is conserved. Results: Fora constant pressure difference of 100 mm Hg applied to the arterial and venous ends of the model, blood flow is diminished for +Gz. At approximately 5 Gz the blood flow predicted by the model is insufficient to maintain normal functioning of the brain. PCSF is approximately equal to the blood pressure in the large intracranial veins for all values of Ct. Extracranial arteries and the intracranial vessels do not collapse, even when Gz is substantially higher than normal. However, the extracranial Veins are collapsed even for moderate +Gz. Conclusions: Even if cardiac output is maintained at normal levels, cerebral perfusion will fall because of the increasing resistance of the cerebral flow circuit. This increase is largely due to the collapse of the extracranial veins, which begins at moderate Gz and becomes dominant at a Gz of approximately 4.5.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 12:59:30