1. Intracranial pressure (ICP) monitoring is important for managing patients with severe traumatic brain injury. ICP above 20-25 mmHg should be treated to reduce pressure. 2. Maintaining a cerebral perfusion pressure above 70 mmHg is effective, while pressures below 50 mmHg should be avoided. Additional monitoring of cerebral blood flow and oxygenation can help guide treatment. 3. Surgical decompression through craniectomy is an effective treatment for reducing high ICP and may improve outcomes, though results are still controversial. Younger patients and earlier surgery seem to benefit most.

1. ICP Management Jonathan R. Jagid, M.D. Associate Professor of Neurological Surgery University of Miami

3. 2o Mechanisms

4. Cerebral Ischemia: What Happens? activation of protein kinase enzymes electrical depolarization cytoskeleton breakdown Ischemic Event Triggers Chemical Cascade blood/brain barrier breakdown oxygen radicals production release of neurotransmitters

5. All strategies targeted towards attenuation of ischemia

6. Facts about High ICP… Commonest cause of death, in Traumatic Brain Injury(80%), severe occlusive stroke, SAH,ICH,Cardiac arrest. Commonest mechanism of brain death. UNDERSTAND THE PATHOMECHANISMS!!

8. Indications for ICP Monitoring No Level I evidence for ICP Monitoring Level II Evidence Should monitor all salvageable patients with severe (GCS 3-8) TBI and abnormal CT scan 60% have high ICP Level III Evidence Also indicated in patients with severe TBI and negative CT Scan if 2 or more criteria met: Age ≥ 40 years, unilateral/bilateral posturing, SBP < 90 mmHg 60% high ICP

9. Intracranial Pressure Monitoring Technology I. In the current state of technology the ventricular catheter connected to an external strain gauge is the most accurate, low cost, and reliable method of monitoring intracranial pressure (ICP). It also can be recalibrated in situ. ICP transduction via fiberoptic or micro strain gauge devices placed in ventricular catheters provide similar benefits, but at a higher cost. Parenchymal ICP monitors cannot be recalibrated during monitoring. Comparison to zero drift after removal for current parenchymal micro strain gauge transduced ICP monitors is negligible at levels > +/-5 mmHg. The measurement drift is independent of duration of monitoring. Subarachnoid, subdural, and epidural monitors (fluid coupled or pneumatic) are less accurate. $$ X Subarachnoid, subdural, epidural

10. When should treatment be initiated? ICP > 20-25 Ratanalert et al. 2004, Prospective trial of 27 patients Grouped into ICP treatment thresholds of 20 or 25mmHg. Treatment protocols were similar between Groups with CPP kept as > 70 and SjO2 at > 54% No difference in outcome.

11. Marmarou et al, 1991 Prospectively collected database of 1,030 severe TBI patients 428 met ICU monitoring criteria Analyzed for monitoring parameters that determined outcome and their threshold values Results Threshold value of 20mm Hg found to be best correlate with outcome

12. Cerebral Perfusion Pressure B. Level 2 Aggressive attempts to maintain cerebral perfusion pressure (CPP) above 70 mm Hg with fluids and pressors should be avoided because of the risk of adult respiratory distress syndrome (ARDS). C. Level 3 CPP < 50 mm Hg should be avoided. The CPP value to target lies within the range of 50 – 70 mm Hg. Patients with intact pressure autoregulation tolerate higher CPP values. Ancillary monitoring of cerebral blood flow, cerebral oxygenation, cerebral oxygen extraction or lactate production, and cerebral metabolism can facilitate CPP management X >70 X <50 50-70

13. ICP Monitoring to “titrate” therapy To severity

14. Effect of Guidelines-Based Protocols Consistent application of an acute care protocol based on the Guidelines for the management of severe traumatic brain injury improves outcome Class 2 study Two groups of patients were studied. Group I, the pre-TBI guidelines group consisting of 37 patients admitted between January 1994 and June 1997, was managed with an emphasis on ICP reduction. Group II, the post-TBI guidelines group consisting of 56 patients admitted between June 1997 and December 1999, was managed with an emphasis on concurrent ICP reduction, CPP enhancement, and maximization of cerebral oxygenation Palmer, S. J Mission Regional Medical Center, Mission Viejo California J Trauma 2001;50: 657-664

15. What Else is occuring? Autoregulatory dysfunction Compliance issue Are these variables equal for all injuries?

16. PROBABLY NOT!

17. Intracranial Pressure Wave Form

18. Analysis ICP Waveform has 3 components Pulse waveform Respiratory waveform Slow waves or Lundberg B waves Pulse waveform can be divided into several harmonic components Most prominent has frequency equal to heart rate

19. Amplitude of this component is called AMP A correlation coefficient can be obtained between AMP and mean ICP This correlation coefficient represents cerebral compliance (RAP)

21. Cerebrovascular Pressure Reactivity (PRx) Indication of autoregulatory state Ability of vascular smooth muscle to respond to changes in transmural pressure Response of ICP to changes in MAP Normal response is vasoconstriction to increased MAP increase in MAP, decrease in ICP

22. How to measure? Do not want to manipulate MAP in head injured patients Takes advantage of slow waves in MAP due to mechanical ventilation These minor fluctuations are compared to ICP and define PRx or cerebrovascular pressure reactivity index

23. Negative values correlate with intact autoregulatory response Validated with PET CBF and CMRO2 Zweifel, et al., Neurosurg Focus 25 (10):E2, 2008

24. Zweifel, et al., Neurosurg Focus 25 (10):E2, 2008

25. Zweifel, et al., Neurosurg Focus 25 (10):E2, 2008

26. Zweifel, et al., Neurosurg Focus 25 (10):E2, 2008

27. Zweifel, et al., Neurosurg Focus 25 (10):E2, 2008

28. Surgical Decompression If other options fail, entertain hemicraniectomy, holocraniectomy, lobectomies, etc. Results controversial

29. Massive decompressive craniectomy and duroplasty- the most effective current therapy, for high ICP…..??

30. Miami Experience 2003-2009 47 patients Ages 15-54 Follow up range 6 mos to 5 years 6 unilateral, 41 bifrontal

31. Pre vs. Post Operative ICP’s

32. Time of Surgery 87% 60% 49%

33. Severity vs. Timing

34. GCS vs. Timing

35. Timing of Surgery vs. GOS 61% 22% 50% 17% 80% 60% 30% 100% 20% 10% 20% 20% 100% 10%

36. Age vs. Outcome # of Patients Age

37. GCS 3-8 vs. GOS 64% 37% 27% 44% 66% 100% 13% 100% 67% 9% 17% 17% 33% 6%

38. Chibbaro, et al., World Neuros., 75 (3/4):558-562, Mar/Apr 2011. Chibbaro, et al., World Neurosurgery, 75 (3/4): 558-562

39. Chibbaro, et al., World Neuros., 75 (3/4):558-562, Mar/Apr 2011. Chibbaro, et al., World Neurosurgery, 75 (3/4): 558-562

40. Timofeev, et al., J. Neurosurg, vol 108, Jan 2008

43. Hypothermia lowers Intracranial Hypertension

45. Intravascular Cooling

46. NABIS:H Mortality N=199 N=193

47. NABIS:H Outcome 57% 57% N=199 N=193

48. Subgroup (Age≤45, Hypo on admission) 76% 52%

49. NABIS:H II

51. ICP

52. Zweifel, et al., Neurosurg. Focus, Vol 25, 2008 Zweifel, et al, Neurosurg Focus 25 (10):E2, 2008

53. Future Targets Aquaporins AQP4 MMPs Vasoactive Agents Complex Processes which are time dependent Upregulation of AQP4 reduces Vasogenic edema Downregulation improves cytotoxic edema

54. Conclusion Head injury is variable from patient to patient ICP control critical Craniectomy improves most bedside paramaters Does it improve outcome Hypothermia improves ICP, Neuoprotection?