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  • Assessment of Cerebrovascular Autoregulation Using Regional Cerebral Blood Flow in Severe Traumatic Brain Injury

    Final Number:

    Ryan David Tackla MD; Jason Hinzman PhD; Mark Magner MD; Norberto O. Andaluz MD; Jed Hartings PhD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2015 Annual Meeting

    Introduction: Management of severe traumatic brain injury (TBI)is primarily focused on avoiding secondary ischemic events. Cerebrovascular autoregulation, the intrinsic ability of vessels to maintain constant and adequate perfusion over a wide range of cerebral perfusion pressures (CPP), is often impaired in severe TBI patients, making it difficult to determine if CPP management is sufficient. Currently, autoregulation can be assessed using intracranial pressure as a surrogate of cerebral blood volume, but this measure is indirect and not applicable to surgical patients following decompressive craniectomy. Here, we describe a novel and direct approach to continuously assess cerebrovascular autoregulation using a regional cerebral blood flow monitor (Hemedex®) that also provides absolute measures of perfusion.

    Methods: In 7 patients with severe brain trauma who underwent surgical decompression, a Hemedex® rCBF probe was placed intraoperatively in peri-lesional tissue. Autoregulation was assessed as a moving Pearson correlation between CPP and rCBF (rCBFx).

    Results: Composite data from all patients revealed a U-shaped autoregulation curve with intact autoregulation (<0.3) over a wide CPP range (45-90 mmHg) and maximal autoregulation (CPPopt) at 55-60 mmHg. All rCBF values fell below the ischemic threshold (<18 ml/100g/min) when CPPs were <50 mmHg compared with 11% ischemia when CPPs >50 mmHg (P<0.05). We examined the percent time during which both autoregulation was intact and rCBF exceeded the ischemic threshold. In the composite data, this variable was maximal in the CPP range of 75-80 mmHg (CPPideal). In individual patients, the range of CPPs with intact autoregulation varied widely. Individual CPPopt values ranged between 60-100 mmHg and CPPideal ranged between 65-105 mmHg.

    Conclusions: These data demonstrate that autoregulatory impairment varies considerably between patients and that CPP target ranges based on consideration of autoregulation alone are significantly lower than when tissue ischemia is additionally considered. Assessment of cerebrovascular autoregulation with Hemedex® rCBF monitor could be utilized to personalize CPP management that optimizes both autoregulation and perfusion.

    Patient Care: By using rCBF monitoring to provide a continuous and direct assessment of cerebrovascular autoregulation, our research will improve patient care by allowing clinicians to continuously target cerebral perfusion pressure(s) that both maximize autoregulation and avoid ischemia on a patient-to-patient basis.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of autoregulation-directed therapy as it relates to improvement in TBI outcomes, 2) Discuss the current techniques capable of continuously monitoring autoregulation, and their limitations, in the intensive care setting, 3) Identify a novel rCBF monitor-based index of autoregulation which is both feasible and could be used to guide CPP management strategies to optimize both autoregulation and perfusion

    References: 1. Werner C, Engelhard K, (2007) Pathophysiology of traumatic brain injury. Br J Anaesth 99: 4-9 2. Paulson OB, Strandgaard S, Edvinsson L, (1990) Cerebral autoregulation. Cerebrovasc Brain Metab Rev 2: 161-192 3. Bouma GJ, Muizelaar JP, Bandoh K, Marmarou A, (1992) Blood pressure and intracranial pressure-volume dynamics in severe head injury: relationship with cerebral blood flow. J Neurosurg 77: 15-19 4. Czosnyka M, Smielewski P, Piechnik S, Steiner LA, Pickard JD, (2001) Cerebral autoregulation following head injury. J Neurosurg 95: 756-763 5. Zweifel C, Lavinio A, Steiner LA, Radolovich D, Smielewski P, Timofeev I, Hiler M, Balestreri M, Kirkpatrick PJ, Pickard JD, Hutchinson P, Czosnyka M, (2008) Continuous monitoring of cerebrovascular pressure reactivity in patients with head injury. Neurosurg Focus 25: E2 6. Lam JM, Hsiang JN, Poon WS, (1997) Monitoring of autoregulation using laser Doppler flowmetry in patients with head injury. J Neurosurg 86: 438-445 7. Jaeger M, Schuhmann MU, Soehle M, Meixensberger J, (2006) Continuous assessment of cerebrovascular autoregulation after traumatic brain injury using brain tissue oxygen pressure reactivity. Crit Care Med 34: 1783-1788 8. Reinert M, Andres RH, Fuhrer M, Muller A, Schaller B, Widmer H, (2007) Online correlation of spontaneous arterial and intracranial pressure fluctuations in patients with diffuse severe head injury. Neurol Res 29: 455-462 9. Steiner LA, Czosnyka M, Piechnik SK, Smielewski P, Chatfield D, Menon DK, Pickard JD, (2002) Continuous monitoring of cerebrovascular pressure reactivity allows determination of optimal cerebral perfusion pressure in patients with traumatic brain injury. Crit Care Med 30: 733-738 10. Dewey RC, Pieper HP, Hunt WE, (1974) Experimental cerebral hemodynamics. Vasomotor tone, critical closing pressure, and vascular bed resistance. J Neurosurg 41: 597-606 11. Czosnyka M, Miller C, (2014) Monitoring of Cerebral Autoregulation. Neurocrit Care 12. Steiner LA, Coles JP, Johnston AJ, Chatfield DA, Smielewski P, Fryer TD, Aigbirhio FI, Clark JC, Pickard JD, Menon DK, Czosnyka M, (2003) Assessment of cerebrovascular autoregulation in head-injured patients: a validation study. Stroke 34: 2404-2409 13. Czosnyka M, Smielewski P, Kirkpatrick P, Piechnik S, Laing R, Pickard JD, (1998) Continuous monitoring of cerebrovascular pressure-reactivity in head injury. Acta Neurochir Suppl 71: 74-77 14. Aries MJ, Czosnyka M, Budohoski KP, Steiner LA, Lavinio A, Kolias AG, Hutchinson PJ, Brady KM, Menon DK, Pickard JD, Smielewski P, (2012) Continuous determination of optimal cerebral perfusion pressure in traumatic brain injury. Crit Care Med 40: 2456-2463 15. Timofeev I, Czosnyka M, Nortje J, Smielewski P, Kirkpatrick P, Gupta A, Hutchinson P,(2008) Effect of decompressive craniectomy on intracranial pressure and cerebrospinal compensation following traumatic brain injury. J Neurosurg 108: 66-73 16. Czosnyka M, Smielewski P, Kirkpatrick P, Menon DK, Pickard JD, (1996) Monitoring of cerebral autoregulation in head-injured patients. Stroke 27: 1829-1834 17. Soehle M, Jaeger M, Meixensberger J, (2003) Online assessment of brain tissue oxygen autoregulation in traumatic brain injury and subarachnoid hemorrhage. Neurol Res 25: 411-417 18. Radolovich DK, Czosnyka M, Timofeev I, Lavinio A, Hutchinson P, Gupta A, Pickard JD, Smielewski P, (2009) Reactivity of brain tissue oxygen to change in cerebral perfusion pressure in head injured patients. Neurocrit Care 10: 274-279 19. Zweifel C, Castellani G, Czosnyka M, Helmy A, Manktelow A, Carrera E, Brady KM, Hutchinson PJ, Menon DK, Pickard JD, Smielewski P, (2010) Noninvasive monitoring of cerebrovascular reactivity with near infrared spectroscopy in head-injured patients. J Neurotrauma 27: 1951-1958 20. Wilson JA, Shutter LA, Hartings JA, (2013) COSBID-M3: a platform for multimodal monitoring, data collection, and research in neurocritical care. Acta Neurochir Suppl 115: 67-74 21. Lang EW, Mehdorn HM, Dorsch NW, Czosnyka M, (2002) Continuous monitoring of cerebrovascular autoregulation: a validation study. J Neurol Neurosurg Psychiatry 72: 583-586 22. Naqvi J, Yap KH, Ahmad G, Ghosh J, (2013) Transcranial Doppler ultrasound: a review of the physical principles and major applications in critical care. Int J Vasc Med 2013: 629378 23. Steiner LA, Coles JP, Czosnyka M, Minhas PS, Fryer TD, Aigbirhio FI, Clark JC, Smielewski P, Chatfield DA, Donovan T, Pickard JD, Menon DK, (2003)Cerebrovascular pressure reactivity is related to global cerebral oxygen metabolism after head injury. J Neurol Neurosurg Psychiatry 74: 765-770 24. Bratton SL, Chestnut RM, Ghajar J, McConnell Hammond FF, Harris OA, Hartl R, Manley GT, Nemecek A, Newell DW, Rosenthal G, Schouten J, Shutter L, Timmons SD, Ullman JS, Videtta W, Wilberger JE, Wright DW, (2007) Guidelines for the management of severe traumatic brain injury. IX. Cerebral perfusion thresholds. J Neurotrauma 24 Suppl 1: S59-64 25. Juul N, Morris GF, Marshall SB, Marshall LF, (2000) Intracranial hypertension and cerebral perfusion pressure: influence on neurological deterioration and outcome in severe head injury. The Executive Committee of the International Selfotel Trial. J Neurosurg 92: 1-6

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