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Anesthesia Medication Effects on Cerebral Hemodynamics PowerPoint Presentation
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Anesthesia Medication Effects on Cerebral Hemodynamics

Anesthesia Medication Effects on Cerebral Hemodynamics

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Anesthesia Medication Effects on Cerebral Hemodynamics

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  1. Anesthesia Medication Effects on Cerebral Hemodynamics

  2. INCREASE DECREASE

  3. Site of autoregulation

  4. Site of autoregulation • Site of medication effects

  5. Site of autoregulation • Site of medication effects Difficult to measure

  6. Site of autoregulation • Site of medication effects Difficult to measure Varies to a lesser degree than CBF

  7. CBF Autoregulation

  8. CBF Autoregulation

  9. Site of autoregulation • Site of medication effects Difficult to measure Varies to a lesser degree than CBF Brain Tissue, CSF, CBV

  10. Site of autoregulation • Site of medication effects Difficult to measure Varies to a lesser degree than CBF Brain Tissue, CSF, CBV Focal vs global Affects all variables

  11. (MAP-ICP)= CPP _____________ Resistance

  12. MAP- ICP Directly Proportional _____________ Resistance

  13. MAP- ICP Directly Proportional _____________ Resistance Inversely proportional

  14. MAP- ICP Metabolism _____________(CMRO2) Resistance

  15. Normal Values:

  16. Normal Values: 15-20% of CO

  17. Normal Values: 15-20% of CO 750 mL/min

  18. Normal Values: 15-20% of CO 750 mL/min 50 mL/100g/min

  19. Questions

  20. Question #1 • In the normal patient, what is the largest component of the cranial vault? • A. Brain Tissue • B. CSF • C. CBV • D. MAP

  21. Answer • Question #1: A) Brain Tissue • The 3 components that make up the cranial vault are brain tissue, CSF, and CBV. Brain tissue accounts for 80% of the space while CSF and CBV account for 10% each. However, when ICP is altered it is typically caused by a change in CBV.

  22. Question #2 • Which of the following parameters is true for the normal patient? • A. 35% of cardiac output to the brain • B. Blood flow of 50 ml/min/100 g of brain tissue • C. ICP of 17 mmHg • D. Both A and B

  23. Answer • Question #2: B) Blood flow of 50 ml/min/100 g of brain tissue • Normal ICP is <15 and the brain normally receives 15-20% of cardiac output. The typical blood flow to the brain is 750 ml/min or 50 ml/min/100 g of tissue. Cerebral Ischemia begins when blood flow drops below 20 ml/min/100 g and infarct begins at 6 ml/min/100 g of tissue.

  24. Question #3 • All of the following increase CBF, except: • A. Hypercarbia • B. Hypoxia • C. Increased cerebral vascular resistance • D. They all increase CBF

  25. Answer • Question #3: C) Increased cerebral vascular resistance • Both hypercarbia and hypoxia increase CBF. Hypoxia increases CBF by causing an increased metabolic demand. Hypercarbia has a direct vasodilatory effect on the cerebral vasculature. Increased cerebral vascular resistance would decrease CBF.

  26. MAP 60-150

  27. MAP 60-150 Rapid change will still affect CBF

  28. MAP 60-150 Rapid change will still affect CBF Disrupted by : volatile anesthetics

  29. MAP 60-150 Rapid change will still affect CBF Disrupted by : volatile anesthetics HTN

  30. Pt’s Baseline MAPis the best indicator of their autoregulationrange

  31. CBF Autoregulation

  32. CBF Autoregulation