ISSN:
1573-2614
Keywords:
Cerebral blood flow
;
cerebral vascular resistance
;
cerebral perfusion pressure
;
PaCO2
;
PaO2
;
cerebral metabolic rate of oxygen consumption
;
educational model
;
simulation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Computer Science
,
Medicine
Notes:
Abstract Objective.To implement a realistic autoregulation mechanism toenhance an existing educational brain model that displays in real-time thecerebral metabolic rate (CMRO2), cerebral blood flow (CBF),cerebral blood volume (CBV), intracranial pressure (ICP), and cerebralperfusion pressure (CPP). Methods.A dynamic cerebrovascular resistance(CVR) feedback loop adjusts automatically to maintain CBF within a range ofthe CPP and defines autoregulation. The model obtains physiologic parametersfrom a full-scale patient simulator. We assumed that oxygen demand andarterial partial pressure of carbon dioxide (CO2 responsivity) arethe two major factors involved in determining CBF. In addition, our brainmodel increases oxygen extraction up to 70% once CBF becomes insufficient tosupport CMRO2. The model was validated against data from theliterature. Results.The model's response varied less than 9%from the literature data. Similarly, based on correlation coefficients betweenthe brain model and experimental data, a good fit was obtained for curvesdescribing the relationship between CBF and PaCO2 at a meanarterial blood pressure of 150 mm Hg (R2 = 0.92) and 100 mm Hg(R2 = 0.70). Discussion.The autoregulated brain model, withincorporated CO2 responsivity and a variable oxygen extraction,automatically produces changes in CVR, CBF, CBV, and ICP consistent withliterature reports, when run concurrently with a METI full-scale patientsimulator (Medical Education Technologies, Inc., Sarasota, Florida). Once themodel is enhanced to include herniation, vasospasm, and drug effects, itsutility will be expanded beyond demonstrating only basic neuroanesthesiaconcepts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009998606087
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