essentials of intracranial pressure (ICP)

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1. Essentials of Intracranial pressure Facebook: happy Friday knight March, 12 th , 2020

2. outlines Production and flow of CSF Physiology of ICP and Pathophysiology of increased ICP ICP waveform and interpretation ICP monitoring and technology Treatment of elevated ICP

3. Production and flow of cerebrospinal fluid ( csf )

4. Production and flow of CSF CSF: predominately produced by choroid plexuses Absorption at cranial and spinal arachnoid villi (granulations) Volume: 125 – 150 ml: 25 ml in ventricles, 125 ml in subarachnoid spaces Active and delicately controlled secretion + normal absorption = ICP stable

5. https://www.sciencedirect.com/topics/neuroscience/ventricular-system

6. Sakka L, Coll G, Cazal J. Anatomy and physiology of cerebrospinal fluid. European annals of otorhinolaryngology, head and neck diseases. 2011;128:309-316.

7. Variation Adult humans normally form CSF 0.35 ml/min  400 - 600 ml/day CSF dynamics affect brain metabolism CSF formation fluctuates in disease Hypersecretion: choroid plexus papillomas Hyposecretion : NPH, AD Production and flow of CSF

8. Physiology of csf : Pressure CSF Pressure : 10 – 15 mmHg in adult that varies with Systolic pulse wave Respiratoy cycle Abdominal pressure Jugular venous pressure State of arousal Physical activity posture

9. Composition of csf 99% water Na, Cl, Mg: higher concentration than those in plasma K, Ca: lower concentration than those in plasma CSF cell count: < 5cells/mL, no PMN, no RBC Loop diuretics and carbonic anhydrase: reduce CSF secretion and turnover (3-5 times daily)

10. Physiology of intracranial pressure (ICP) and pathophysiology of increased icp

11. Physiology of icp ICP = CSF pressure dynamic Then ICP is reflective of CSF formation Volume storage or compliance CSF absorption

12. Monroe-kellie doctrine V other : volume of any abnormal component  hematoma, tumor Cranium is Nonexpandable incompressible

13. volume Brain parenchyma: 1400 ml Cerebral blood volume: 150 ml CSF volume: 150 ml

14. Reilly P. Management of intracranial pressure and cerebral perfusion. Head injury. London, 1997.

15. Cerebral blood flow CPP = MAP - ICP Pressure autoregulation: MAP 50-150 mmHg is autoregulated to maintain constant CBF

16. pathophysiology A change in components at intracranial space

17. Results of rasing icp CSF can be displaced from ventricles and subarachnoid spaces and exit intracranial compartment via foramen magnum Intravenous blood: displaced via IJVs Arterial vasoconstriction: diffuse cerebral ischemia Cerebral herniation

18. Results of rasing icp : CT brain Midline shift Obliteration of CSF cisterns

19. Pathophysiology: csf Acute obstruction of CSF flow: acute hydrocephalus Hypersecretion of CSF: structurally or functionally alteration of choroid plexus secretion Choroid plexus papillomas and hyperplasia Malabsorption of CSF: cribiform plate obstruction Obstruction of venous outflow

20. Pathophysiology: blood Arterial system Vasodilatation: hypercapnia, drug reaction Venous system Obstruction of venous outflow: thrombosis, inappropriate position of head and neck, pneumothorax

21. Pathophysiology: brain edema Vasogenic Cytotoxic Interstitial osmotic

22. Pathophysiology: mass occupying lesion Tumor Hemorrhage Infection: abscess

23. Clinical presentation of raised icp Quite unreliable pupil asymmetry Unilateral abnormal posture Signs of brain herniation: Cushing’s triad Hypertension Bradycardia Respiratory irregularity

24. Icp waveform and interpretation

25. Icp waveform Gold standard: interventricular monitoring through ventriculostomy Other technologies: devices inserted into Epidural space Subdural space Subarachnoid space Brain parenchyma

26. 3 characteristic peak of decreasing height + correlate with arterial waveform: P1: percussion wave  arterial pulse P2: tidal wave  cerebral compliance P3: dicrotic wave  aortic valve closure Icp waveform: normal

27. https://derangedphysiology.com/main/required-reading/neurology-and-neurosurgery/Chapter%201.0.5/interpretation-intracranial-pressure-waveforms

28. https://derangedphysiology.com/main/required-reading/neurology-and-neurosurgery/Chapter%201.0.5/interpretation-intracranial-pressure-waveforms Cardiac cycle This reflects changes in intrathoracic pressure with respiration. This respiratory variation in ICP diminishes and eventually disappears altogether as intracranial pressure increases.

29. ICP interpretation: rising icp Increasing all amplitudes Waveform morphology doesn’t change

30. Icp interpretation: decreasing cerebral prefusion Decrease amplitude of P1 Due to P1=reflective of arterial pulse in choroid plexus Vasospasm if no raised ICP

31. Icp interpretation: decreasing cerebral compliance Prominent P2 Increase in cerebral bulk: edema Vasospasm if no raised ICP

32. Icp interpretation: increasing icp Flattening of ICP breathing variation

33. Icp interpretation: lundberg waves Pathological waveforms defined by Dr. Nils Lundberg Not frequently seen but if so, in patients with resistant to therapeutic interventions, is the sign of worse outcome Designated as A: plateau wave B: pressure pulse C: Traube-Hering arterial waves

34. Lundberg “A” waves Plateau waves ICP elevation to 50 mmHg for 2 – 20 minutes then abrupt fall to baseline Intact cerebral blood flow autoregulation But impending uncontrollable ICP

35. Lundberg “a” waves 4 phases Drift: decrease CPP  vasodilatation Plateau: vasodilatation  increase ICP Ischemic response phase: decrease CPP  cerebral ischemia  brainstem vasomotor trigger  cushing response Resolution: cushing response  restore CPP

36. Lundberrg “B” waves ICP elevation 10 – 20 mmHg lasting 30 sec – 2 minutes Depends on periodic breathing (PaCO2), increased ICP, decrease cerebral compliance Unclear value in clinical practice

37. Lundberg “c” waves Similar to B waves but more rapid sinusoidal fluctuation Seen in normal ICP waveform Suggestive but not pathognomonic of increased ICP

38. Icp monitoring: methods and technologies

39. Icp monitoring: methods and technologies Anatomical locations of device insertion Standard ICP monitoring: external ventricular drain I ndications Points of insertion Insertion technique C omplications Other technologies

40. Anatomical locations of device insertion Intraventricular – gold standard Intraparenchymal Subarachnoid Subdural epidural https://www.openpr.com/news/476693/global-intracranial-pressure-icp-monitoring-devices-market-raumedic-medtronic-vittamed-spiegelberg-sophysa-ltd.html

41. External ventricular drain A catheter placed into one of the ventricles through burr hole Gold standard Cost effective Most invasive Can also be used for CSF drainage and administration of medicine intrathecally

42. Winn, H. Richard. Youmans and Winn’s Neurological Surgery. Phildelphia : Elsevier, 2017.

43. Icp monitoring: indications Traumatic brain injury with GCS ≤ 8 Subarachnoid hemorrhage Intracranial tumor Intracranial hemorrhage Stroke Hydrocephalus CNS infection Fulminant hepatic failure

44. Icp monitoring: points of insertion Anterior access Kocher: frontal (coronal) – 2 Paine Tubbs - 6 Kaufman - 5 Posterior access Keen: posterior parietal - 1 Frazier: occipital-parietal - 4 Dandy: occipital - 3

45. Kocher’s point 3 cm from midline 1 cm anterior to coronal suture Point needle to nasion and tragus Most common point https://link.springer.com/referenceworkentry/10.1007%2F978-3-642-00418-6_544

46. Paine’s point 2.5 cm superior to supraorbital margin Anterior edge of temporalis muscle Used in aneurysmal surgery via an interhemispheric approach

47. Tubbs’ point Transorbital access to frontal horn Just medial to midpapilary point to roof of orbit

48. Kaufman’s point 4 cm superior to nasion 3 cm lateral to midline Cosmetic concern but rapidly drained

49. Keen’s point 3 FB superior and posterior to unfold pinna Placement in trigone Point for VP shunt

50. Frazier’s point Occipital-parietal 6 cm above inion 3-4 cm from midline Point for VP shunt

51. Dandy’s point Occipital bur hole 3 cm above 2 cm lateral to inion Infants: correspond with lambdoid suture in the midpupillary line Higher risk for visual impairment

52. Insertion technique Right (non-dominant) side is preferred unless contraindication Kocher’s point: Incision is made in sagittal plane Elevate periosteum Apply self-retaining retractor Make a bur hole 1 – 2 cm anterior to coronal suture Control bleeding by bone wax and gelfoam Durotomy by blade No.11 and cauterize dural edge by bipolar

53. Insertion technique Insert ventriculostomy needle perpendicular to brain surface (point to nasion and tragus), not more than 7 cm depth Feel popping sensation and remove stylet Make a tunnel for the catheter Insert catheter Measure opened pressure, collect CSF, and measure closed pressure Fix catheter, hemostasis, and close the skin

54. CT grading of accuracy of the placement of the ventricular catheter Grade 1  - the tip within the ipsilateral lateral ventricle nearing foramen of Monro . Grade 2  - the medial deviation into a contralateral frontal horn or a lateral ventricle. Grade 3  - the lateral deviation through the caudate nucleus along the lateral corner and wall of the frontal horn. Grade 4  - extraventricular catheterization Yoon SY, Kwak Y, Park J. Adjustable Ghajar Guide Technique for Accurate Placement of Ventricular Catheters: A Pilot Study. J Korean Neurosurg Soc. 2017 Sep;60(5):604-609.

55. complications Intracranial and tract hemorrhage Infection: Ventriculitis Technical failure Over-drainage: transtentorial herniation Kinks and blockage by air, blood, and debris Inadvertent vascular injury. Pneumocephalus and pneumoventriculi . CSF leak. Accidental fracture Accidental pull Obstruction by choroid plexus, blood clot or proteinous plug

56. Technologies of icp monitoring Fiberoptic intracranial pressure monitor Miniature strain gauge Spiegelberg parenchymal transducer Hummingbird synergy Telemetric ICP monitoring

57. Treatment of intracranial hypertension

58. principles ICP > 22 mmHg mandates aggressive clinical management (brain trauma foundation 2016) Look for potential problems that exacerbate raised ICP Treat etiology: Space-occupying hematoma: craniotomy and evacuation Hydrocephalus: ventriculostomy and shunt Tumor: dexamethasone/excision Abscess: aspiration/excision

59. Czosnyka M, Pickard JD, Steiner LA. Principles of intracranial pressure monitoring and treatment in Handbook of Clinical Neurology. Elsevier, 2017

60. First level: prevention Head elevation: up to 30 o Maintain SBP: Age 50 – 69 keep SBP ≥ 100 mmHg, other keep SBP ≥ 110 mmHg Normocarbia (PaCO2 35 – 40 mmHg): no role of prophylactiv hyperventilation Normothermia (36 – 37.5 o C) Light sedation CT brain and check for surgical treatment options if ICP > 20 mmHg Avoid hyperglycemia

61. Second level: more invasive CSF drainage in hydrocephalus Hyperosmolar treatment if evidence of herniation shown 20% mannitol 0.25 – 1 g/kg Hypertonic saline: keep Na < 155 meq /L Steroid in vasogenic edema Mild hyperventilation (PaCO2 30 – 34 mmHg): too long will cause global ischemia

62. Third level: controversy Decompressive craniectomy Consider deeper hypothermia: 33 – 34 o C Consider barbiturate coma to maintain CPP

63. conclusion

64. References Winn, H. Richard. Youmans and Winn’s Neurological Surgery. Phildelphia : Elsevier, 2017. Greenberg MS. Handbook of Neurosurgery. 8 th ed. New York: Thieme , 2016. American college of surgeon committee on trauma. ATLS student course manual. 10 th ed. Chicago: American college of surgeon, 2018. Sakka L, Coll G, Cazal J. Anatomy and physiology of cerebrospinal fluid. European annals of otorhinolaryngology, head and neck diseases. 2011;128:309-316. Tumani H, Huss A, and Buchhuber F. T he cerebrospinal fluid and barriers – anatomic and physiologic considerations in Handbook of clinical neurology. Vol3 (3 rd series), 2018. Kirkness CJ et al. Intracranial pressure waveform analysis: clinical and research implications. Journal of neuroscience nursing.2000:32(5):271-277.

65. references Kasprowicz M, Lalou DA, Czosnyka M, Garnett M, Czosnyka Z. Intracranial pressure, its components and cerebrospinal fluid pressure–volume compensation. Acta Neurol Scand 2016: 134: 168–180. Czosnyka M. Increased intracranial pressure: what to do and when?. www.ccmjournal.org . 2013:41(2):688-689. Czosnyka M, Pickard JD, Steiner LA. Principles of intracranial pressure monitoring and treatment in Handbook of Clinical Neurology. Elsevier, 2017. Karimy JK et al. Cerebrospinal fluid hypersecretion in pediatric hydrocephalus. Neurosurg focus. 2016:41(5):1-11. Johanson CE et al. Multiplicity of cerebrospinal fluid functions: new challenges in health and disease. Cerebrospinal fluid research. 2008:5(10):1-32. https://derangedphysiology.com/main/required-reading/neurology-and-neurosurgery/Chapter%201.0.5/interpretation-intracranial-pressure-waveforms

66. references https:// www.researchgate.net/figure/Lundberg-waves-Lundberg-A-waves-are-ICP-increases-for-5-to-10-minutes-They-reflect_fig2_311525129 Raboel PH et al. Intracranial pressure monitoring: invasive versus non-invasive methods – a review. Critical care research and practice. 2012:1-14. https://www.ncbi.nlm.nih.gov/books/NBK545317/ Mortazavi MM et al. The ventricular system of the brain: a comprehensive review of its history, anatomy, histology, embryology, and surgical considerations. Childs N erv Syst. 2013: Wilson WC et al. Trauma: critical care vol 2. New York: Informa , 2007. Morone PJ et al. Craniometrics and Ventricular Access: A Review of Kocher’s , Kaufman’s, Paine’s, Menovksy’s , Tubbs ’, Keen’s , Frazier’s, Dandy’s, and Sanchez’s Points. Operative neurosurgery.2019:0:1-9.

67. references Carney N et al. Guidelines for the Management of Severe Traumatic Brain Injury, Fourth Edition. 2016 Reilly P. Management of intracranial pressure and cerebral perfusion. Head injury. London, 1997. Yoon SY, Kwak Y, Park J. Adjustable Ghajar Guide Technique for Accurate Placement of Ventricular Catheters: A Pilot Study. J Korean Neurosurg Soc. 2017 Sep;60(5):604-609.