Thermal Fluids Modeling of Localized Hypothermia in a Canine Brain

Transcription

1 Thermal Fluids Modeling of Localized Hypothermia in a Canine Brain Graduate Student: Ryan A. Sikorski Thesis Advisor: Dr. Thomas L. Merrill Rowan University Department of Mechanical Engineering August 2 nd 2013 Committee Members: Dr. Smitesh Bakrania Dr. Krishan Bhatia Dr. Jennifer Vernengo 2 1

2 Reperfusion Injury and Therapeutic Hypothermia Other Published Therapeutic Hypothermia Research Previous Models and Final Model Geometry Results Conclusions and Future Work Google Image 3 Mechanical Thrombectomy CNN Tech 4 2

3 Reperfusion Injury Paradox reperfusion sustains, reperfusion damages Inflammation to the tissue Metabolic rate of brain reduced 6-10% per 1 C CNN Tech Therapeutic Hypothermia - What is the critical temperature range? What 5 critical questions should be answered 5 Author Study Tissue Temperature Results Van der Worp, 2007 Animal meta study, 101 different publications, 3300 animals Best results, < 33 C Usage of TH improves outcomes by 30% Schwab, 1998 Human external cooling C, 14 hours Intracranial pressure reduced Krieger, 2001 Human surface cooling hypothermia 32 ±1 C, hours Feasible and safe in patients CNN Tech Neimark, 2007, 2011 Predictive model / Safety trial Estimated temperature reduction of 2.8 C No major complications Simple quantitative model 6 3

4 Problem Statement Summer 2012 Predict tissue temperature in a human thermal fluids model. Summer 2013 Predict blood temperature s in a physiologically accurate canine intracranial model CNN Tech 7 Work Completed 1) Summer 2012 Benchmark Models, Human Carotid Bifurcation - Comsol Conference 2012: Paper & Poster 2) Fall 2012, Winter 2013 In-vitro canine, CFD model -ASME Design of Medical Device Conference: Paper & Poster - ASME Bioengineering Conference 2013: Poster 3) Spring/Summer 2013 Physiological Accurate Canine Blood Model - ASME Journal of Medical Devices: Technical Brief 8 4

5 Assumption Modeling Assumptions Reasoning 1) Steady State < 5% effect on thermal problems, balloon occlusion 2) Rigid Vessel Fluid-structure interaction complexity, reasonable assumption [Waite] 3) Newtonian Flow Vessel diameter is much larger than blood cell, < 5% velocity differential [Steinman] 4) Inlet Laminar Flow Catheter length >> Entry length 5) Constant Wall Temperature Blood only model 9 Governing Equations Steady State Three Dimensional Navier Stokes Equations Steady State Thermal Energy Equation + Q + 5

6 Previous Models CNN Tech 11 Linking the experimental and the computational 12 6

7 13 Circle of Willis 7

8 Area of modeling interest 15 In-Vivo Work 16 8

9 In-Vivo Work 100 ml/min 50 ml/min 70 ml/min 17 Middle Cerebral Artery Inner Carotid Artery 18 9

10 Building a Physiologically Accurate Model 1) Research canine anatomy journals and textbooks 2) Start simple, add complexity 3) Receive feedback from experts - Matt Gounis, etc. 4) Iterate 5) Fine tune for meshing 19 Percent Difference Inlet Mass Flow Rate : Outlet Mass Flow Rate , , , ,000 1,000,000 1,200,000 1,400,000 Number of Elements Fluid Domain 20 10

11

12 Comsol Settings Boundary Condition Value Artery Inlet No Flow, Fully Occluded Catheter Inlet Laminar Inflow, Velocity [m/s] All Flow Outlets Pressure No Viscous [Taylor] 0 [Pa] Wall Boundaries No Slip Blood/ Wall Thermal Conductivity Constant 0.45 / 0.49[W/(m*K)] Artery Wall Temperature Temperature [K] Catheter Inlet Temperature Temperature, Varies with Flow [K] 23 Location Volumetric Flow Rate [ml/min] % % % % % % % % % of 90 ml/min total flow

13 308 Temperature [K] Branch #1 Branch #2 Branch # S Length ]mm] Temperature [K] ml/min 80 ml/min 100 ml/min S Length [mm] 26 13

14 Temperature [K] ml/min 80 ml/min 100 ml/min S Length [mm] 27 Temperature [K] S Length [mm] 60 ml/min 80 ml/min 100 ml/min 28 14

15 Temperature [K] S Length [mm] 60 ml/min 80 ml/min 100 ml/min Temp [K] Volumetric Flow Rate [ml/min] Computational Blood, 40mm along bifurcation path In vivo tissue 10 minutes 30 15

16 Model Limitations 1) Constant Wall Temperature 2) Steady State 3) Based on Two-Dimensional Angiograms 4) No Tissue Domain 31 Proposed Future Work 1. Address limitations 2. Increase computational capacity, switch to finite volume solver 3. Transition to human model, building off of canine work 4. Incorporate scanned images to construct accurate 3D model 32 16

17 Acknowledgements Rowan University Department of Mechanical Engineering Barbara Wynn Faculty and Lab Staff South Jersey Technology Park FocalCool, LLC Denise Merrill Jennifer Mitchell Madina Yermagambetova Anthony La Barck Thesis Committee Dr. Smitesh Bakrania Dr. Krishan Bhatia Dr. Jennifer Vernengo Thesis Adviser Dr. Thomas Merrill Mom + Dad Graduate Students Dylan McNally Jared Wasserman 33 References [1] Heart and Stroke Foundation, [Online]. Available: [Accessed: 08 Jan 2013]. [2] Merci Retriever, [3] H. B. van der Worp, E. S. Sena, G. a Donnan, D. W. Howells, and M. R. Macleod, Hypothermia in animal models of acute ischaemic stroke: a systematic review and meta analysis., Brain : a journal of neurology, vol. 130, no. Pt 12, pp , Dec [4] W. S. Smith, G. Sung, J. Saver, R. Budzik, G. Duckwiler, D. S. Liebeskind, H. L. Lutsep, M. M. Rymer, R. T. Higashida, S. Starkman, Y. P. Gobin, D. Frei, T. Grobelny, F. Hellinger, D. Huddle, C. Kidwell, W. Koroshetz, M. Marks, G. Nesbit, and I. E. Silverman, Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial., Stroke; a journal of cerebral circulation, vol. 39, no. 4, pp , Apr [5] NINDS t PA Stroke Study Group, Tissue plasminogen activator for acute ischemic stroke, New England Journal of Medicine, vol. 333, pp , [6] T. Merrill, D. R. Merrill, and J. Akers, Localized Brain Tissue cooling For Use During Intracranial Thrombectomy, [7] H. B. van der Worp, M. R. Macleod, and R. Kollmar, Therapeutic hypothermia for acute ischemic stroke: ready to start large randomized trials?, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism, vol. 30, no. 6, pp , Jun [8] S. Schwab, S. Schwarz, M. Spranger, E. Keller, M. Bertram, and W. Hacke, Moderate Hypothermia in the Treatment of Patients With Severe Middle Cerebral Artery Infarction, Stroke, vol. 29, no. 12, pp , Dec [9] S. Schwab, S. Schwarz, M. Spranger, E. Keller, M. Bertram, and W. Hacke, Moderate Hypothermia in the Treatment of Patients With Severe Middle Cerebral Artery Infarction, Stroke, vol. 29, no. 12, pp , Dec [10] M. a Neimark, A. A. Konstas, A. F. Laine, and J. Pile Spellman, Integration of jugular venous return and circle of Willis in a theoretical human model of selective brain cooling., Journal of applied physiology (Bethesda, Md. : 1985), vol. 103, no. 5, pp , Nov [11] M. a Neimark, A. A. Konstas, J. H. Choi, A. F. Laine, and J. Pile Spellman, Brain cooling maintenance with cooling cap following induction with intracarotid cold saline infusion: a quantitative model., Journal of theoretical biology, vol. 253, no. 2, pp , Jul [12] A. A. Konstas, M. a Neimark, A. F. Laine, and J. Pile Spellman, A theoretical model of selective cooling using intracarotid cold saline infusion in the human brain., Journal of applied physiology (Bethesda, Md. : 1985), vol. 102, no. 4, pp , Apr [13] E. Tanaka, a Tanaka, T. Sekka, Y. Shinozaki, K. Hyodo, K. Umetani, and H. Mori, Digitized cerebral synchrotron radiation angiography: quantitative evaluation of the canine circle of Willis and its large and small branches., AJNR. American journal of neuroradiology, vol. 20, no. 5, pp , May [14] B. T. Kang, D. P. Jang, S. H. Gu, Y. B. Kim, C. Y. Lim, J. H. Lee, E. J. Woo, Z. H. Cho, and H. M. Park, Three dimensional time of flight magnetic resonance angiography of intracranial vessels in a canine model of ischemic stroke with permanent occlusion of the middle cerebral artery., Comparative medicine, vol. 59, no. 1, pp. 72 7, Feb [15] J. Hendrikse, a F. van Raamt, Y. van der Graaf, W. P. T. M. Mali, and J. van der Grond, Distribution of cerebral blood flow in the circle of Willis., Radiology, vol. 235, no. 1, pp , Apr [16] L. Waite and J. Fine, Applied Biofluid Mechanics. New York, NY: McGraw Hill, [17] T. L. Merrill, D. R. Merrill, T. J. Nilsen, and J. E. Akers, Design of a cooling guide catheter for rapid heart cooling, ASME Journal of Medical Devices, vol. 4, no. 3, pp , [18] K. Perktold, M. Resch, and H. Florian, Pulsatile Non Newtonian Flow Characteristics in a 3 Dimensional Human Carotid Bifurcation, 34 Journal of Biomechanical Engineering, no. 113, pp ,

18 35 18