title: Model-based assessment of tissue perfusion and temperature in deep hypothermic patients.
abstract: Deep hypothermic circulatory arrest is necessary for some types of cardiac and aortic surgery. Perfusion of the brain can be maintained using a heart-lung machine and unilateral antegrade cerebral perfusion. Cooling rates during extracorporeal circulation depend on local perfusion. A core temperature of 24 degrees C-25 degrees C is aimed at to extend ischemic tolerance of tissues. Information on cerebral perfusion and temperature is important for the safety of patients, but hardly accessible to measurement. A combined simulation model of hemodynamics and temperature is presented in this paper. The hemodynamics model employs the transmission-line approach and integrates the Circle of Willis (CoW). This allows for parameterization of individual aberrations. Simulation results of cerebral perfusion are shown for two configurations of the CoW. The temperature model provides spatial information on temperature fields. It considers heat transfer in the various tissues retrieving data of local tissue perfusion from the hemodynamics model. The combined model is evaluated by retrospective simulation of two aortic operations.
authors.affiliation: ITK Engineering AG, Herxheim 76863, Germany. michael.schwarz@itk-engineering.de
authors.forename: Michael
authors.initials: M
authors.lastname: Schwarz
authors.forename: Martin W
authors.initials: MW
authors.lastname: Krueger
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Busch
authors.forename: Christoph
authors.initials: C
authors.lastname: Benk
authors.forename: Claudia
authors.initials: C
authors.lastname: Heilmann
mesh_terms: D001013:Aorta, Thoracic; D001158:Arteries; D001831:Body Temperature / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D002941:Circle of Willis; D050792:Circulatory Arrest, Deep Hypothermia Induced; D003198:Computer Simulation; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D009928:Organ Specificity; D010477:Perfusion; D012867:Skin