• 1. Tayal VS, Neulander M, Norton HJ, et al. Emergency department sonographic measurement of optic nerve sheath diameter to detect findings of increased intracranial pressure in adult head injury patients. Ann Emerg Med 2007; 49: 508514.

    • Search Google Scholar
    • Export Citation
  • 2. Dewey CW, Fletcher DJ. Head trauma management. In: Dewey CW, ed. A practical guide to canine and feline neurology. 2nd ed. Ames, Iowa: Wiley-Blackwell, 2008; 6: 220233.

    • Search Google Scholar
    • Export Citation
  • 3. Chrisman C, Mariani C, Platt S, et al. Head trauma. In: Chrisman C, Mariani C, Platt S, et al, eds. Neurology for the small animal practitioner. Jackson, Wyo: Teton New Media, 2003; 5051.

    • Search Google Scholar
    • Export Citation
  • 4. Syring RS. Assessment and treatment of central nervous system abnormalities in the emergency patient. Vet Clin North Am Small Anim Pract 2005; 35: 343358.

    • Search Google Scholar
    • Export Citation
  • 5. Lorenz M, Coates J, Kent M. Stupor or coma. In: Lorenz M, Coates J, Kent M, eds. Handbook of veterinary neurology. 5th ed. St Louis: Elsevier Saunders, 12;349355.

    • Search Google Scholar
    • Export Citation
  • 6. Jagannathan J, Okonkwo D, Yeoh HK, et al. Long-term outcomes and prognostic factors in pediatric patients with severe traumatic brain injury and elevated intracranial pressure. J Neurosurg Pediatr 2008; 2: 240249.

    • Search Google Scholar
    • Export Citation
  • 7. Stocchetti N, Maas A. Traumatic intracranial hypertension. N Engl J Med 2014; 370: 21212130.

  • 8. Dewey CW, Bailey C, Haskins S, et al. Evaluation of an epidural intracranial pressure monitoring system in cats. J Vet Emerg Crit Care 1997; 7: 2033.

    • Search Google Scholar
    • Export Citation
  • 9. Eide PK. Comparison of simultaneous continuous intracranial pressure (ICP) signals from ICP sensors placed within the brain parenchyma and the epidural space. Med Eng Phys 2008; 30: 3440.

    • Search Google Scholar
    • Export Citation
  • 10. Blaivas M, Theodoro D, Sierzenski PR. Elevated intracranial pressure detected by bedside emergency ultrasonography of optic nerve sheath. Acad Emerg Med 2003; 10: 376381.

    • Search Google Scholar
    • Export Citation
  • 11. Hansen HC, Helmke K. The subarachnoid space surrounding the optic nerves. An ultrasound study of the optic nerve sheath. Surg Radiol Anat 1996; 18: 323328.

    • Search Google Scholar
    • Export Citation
  • 12. Hansen HC, Helmke K. Validation of the optic nerve sheath response to changing cerebrospinal fluid pressure: ultrasound findings during intrathecal infusion tests. J Neurosurg 1997; 87: 3440.

    • Search Google Scholar
    • Export Citation
  • 13. Newman WD, Hollman AS, Dutton GN, et al. Measurement of optic nerve sheath diameter by ultrasound: a means of detecting acute raised intracranial pressure in hydrocephalus. Br J Ophthalmol 2002; 86: 11091113.

    • Search Google Scholar
    • Export Citation
  • 14. Samuelson DA. Ophthalmic anatomy. In: Gelatt KN, Gilger BC, Kern TJ, eds. Veterinary ophthalmology. Vol 2. 5th ed. Ames, Iowa: Wiley-Blackwell, 2013; 39171.

    • Search Google Scholar
    • Export Citation
  • 15. Murphy C, Samuelson D, Pollock R. The eye. In: De Lahunta E, ed. Miller's anatomy of the dog. 4th ed. St Louis: Elsevier, 2013; 756.

  • 16. Liu D, Kahn M. Measurement and relationship of subarachnoid pressure of the optic nerve to intracranial pressures in fresh cadavers. Am J Ophthalmol 1993; 116: 548556.

    • Search Google Scholar
    • Export Citation
  • 17. Geeraerts T, Launey Y, Martin L, et al. Ultrasonography of the optic nerve sheath may be useful for detecting raised intracranial pressure after severe brain injury. Intensive Care Med 2007; 33: 17041711.

    • Search Google Scholar
    • Export Citation
  • 18. Lee HC, Choi HJ, Choi CM, et al. Ultrasonographic measurement of optic nerve sheath diameter in normal dogs. J Vet Sci 2003; 4: 265268.

    • Search Google Scholar
    • Export Citation
  • 19. Royston P, Altman DG. Regression using fractional polynomials of continuous covariates: parsimonious parametric modeling. J R Stat Soc Ser C Appl Stat 1994; 43: 429467.

    • Search Google Scholar
    • Export Citation
  • 20. Helmke K, Burdelski M, Hansen HC. Detection and monitoring of intracranial pressure dysregulation in liver failure by ultrasound. Transplantation 2000; 70: 392395.

    • Search Google Scholar
    • Export Citation
  • 21. Malayeri AA, Bavarian S, Mehdizadeh M. Sonographic evaluation of optic nerve diameter in children with raised intracranial pressure. J Ultrasound Med 2005; 24: 143147.

    • Search Google Scholar
    • Export Citation
  • 22. Moretti R, Pizzi B, Cassini F, et al. Reliability of optic nerve ultrasound for the evaluation of patients with spontaneous intracranial hemorrhage. Neurocrit Care 2009; 11: 406410.

    • Search Google Scholar
    • Export Citation
  • 23. Soldatos T, Karakitsos D, Chatzimichail K, et al. Optic nerve sonography in the diagnostic evaluation of adult brain injury. Crit Care [serial online]. 2008; 12: R67. Available at: ccforum.com/content/12/3/R67. Accessed Jan 6, 2014.

    • Search Google Scholar
    • Export Citation
  • 24. Helmke K, Hansen HC. Fundamentals of transorbital sonographic evaluation of the optic nerve sheath expansion under intracranial hypertension I. Experimental study. Pediatr Radiol 1996; 26: 701705.

    • Search Google Scholar
    • Export Citation
  • 25. Helmke K, Hansen HC. Fundamentals of transorbital sonographic evaluation of the optic nerve sheath expansion under intracranial hypertension II. Patient study. Pediatr Radiol 1996; 26: 706710.

    • Search Google Scholar
    • Export Citation
  • 26. Shofty B, Ben-Sira L, Constantini S, et al. Optic nerve sheath diameter on MR imaging: establishment of norms and comparison of pediatric patients with idiopathic intracranial hypertension with healthy controls. Am J Neuroradiol 2012; 33: 366369.

    • Search Google Scholar
    • Export Citation
  • 27. Moretti R, Pizzi B. Ultrasonography of the optic nerve in neurocritically ill patients. Acta Anaesthesiol Scand 2011; 55: 644652.

  • 28. Hamilton DR, Sargsyan A, Melton S, et al. Sonography for determining the optic nerve sheath diameter with increasing intracranial pressure in a porcine model. J Ultrasound Med 2011; 30: 651659.

    • Search Google Scholar
    • Export Citation
  • 29. Packer RA, Simmons JP, Davis NM, et al. Evaluation of an acute focal epidural mass model to characterize the intracranial pressure-volume relationship in healthy Beagles. Am J Vet Res 2011; 72: 103108.

    • Search Google Scholar
    • Export Citation
  • 30. Qureshi AI, Wilson D, Traystman R. Treatment of elevated intracranial pressure in experimental intracerebral hemorrhage: comparison between mannitol and hypertonic saline. Neurosurgery 1999; 44: 10551063.

    • Search Google Scholar
    • Export Citation
  • 31. Scrivani PV, Fletcher DJ, Cooley SD, et al. T2-weighted magnetic resonance imaging measurements of optic nerve sheath diameter in dogs with and without presumed intracranial hypertension. Vet Radiol Ultrasound 2013; 54: 263270.

    • Search Google Scholar
    • Export Citation
  • 32. Artru AA. Relationship between cerebral blood volume and CSF pressure during anesthesia with isoflurane or fentanyl in dogs. Anesthesiology 1984; 60: 575579.

    • Search Google Scholar
    • Export Citation

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Relationship between intracranial pressure as measured by an epidural intracranial pressure monitoring system and optic nerve sheath diameter in healthy dogs

Laura A. Ilie DVM1, Elizabeth J. Thomovsky DVM, MS2, Paula A. Johnson DVM3, R. Timothy Bentley BVSc4, Hock Gan Heng DVM, MVS, MS5, Hee C. Lee DVM, PhD6, and George E. Moore DVM, PhD7
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  • 1 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 2 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 3 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 4 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 5 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 6 Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.
  • | 7 Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907.

Abstract

OBJECTIVE To evaluate the association between ultrasonographically measured optic nerve sheath diameter (ONSD) and acute increases in intracranial pressure (ICP) as measured by an epidural intracranial pressure monitoring system (EICPMS) in healthy dogs.

ANIMALS 6 young healthy dogs.

PROCEDURES An EICPMS connected to a pressure monitor was used to generate a continuous pressure waveform in each anesthetized dog. A 22-gauge IV catheter was inserted into the brain parenchyma through the contralateral parietal bone, and 0.5 to 2.0 mL of anticoagulated autologous blood was injected at predetermined intervals. At baseline (immediately after EICPMS placement) and following each injection, the ICP as indicated by EICPMS was recorded, and 3 ultrasonographic images of the optic nerve sheath of each eye were obtained. The ONSD was measured at maximum diameter and at 5 mm caudal to the optic disk.

RESULTS In linear models, the maximum ONSD was positively associated with increasing ICP. Specifically, the rate of maximum ONSD increase was greater for pressures ≤ 20 mm Hg above baseline (0.0534 mm/1 mm Hg ICP increase) than for pressures > 40 mm Hg above baseline (0.0087 mm/1 mm Hg ICP increase). The relationship of ICP to maximum ONSD was slightly nonlinear and best explained by comparison of fractional polynomial regression models.

CONCLUSIONS AND CLINICAL RELEVANCE ICP was positively and nonlinearly associated with increasing maximum ONSD, especially when ICP was ≤ 20 mm Hg above baseline, supporting the conclusion that ultrasonographic measurement of maximum ONSD may provide a noninvasive monitoring tool for evaluation of ICP in dogs. Further research is needed to assess the utility of these measurements in clinical patients.

Abstract

OBJECTIVE To evaluate the association between ultrasonographically measured optic nerve sheath diameter (ONSD) and acute increases in intracranial pressure (ICP) as measured by an epidural intracranial pressure monitoring system (EICPMS) in healthy dogs.

ANIMALS 6 young healthy dogs.

PROCEDURES An EICPMS connected to a pressure monitor was used to generate a continuous pressure waveform in each anesthetized dog. A 22-gauge IV catheter was inserted into the brain parenchyma through the contralateral parietal bone, and 0.5 to 2.0 mL of anticoagulated autologous blood was injected at predetermined intervals. At baseline (immediately after EICPMS placement) and following each injection, the ICP as indicated by EICPMS was recorded, and 3 ultrasonographic images of the optic nerve sheath of each eye were obtained. The ONSD was measured at maximum diameter and at 5 mm caudal to the optic disk.

RESULTS In linear models, the maximum ONSD was positively associated with increasing ICP. Specifically, the rate of maximum ONSD increase was greater for pressures ≤ 20 mm Hg above baseline (0.0534 mm/1 mm Hg ICP increase) than for pressures > 40 mm Hg above baseline (0.0087 mm/1 mm Hg ICP increase). The relationship of ICP to maximum ONSD was slightly nonlinear and best explained by comparison of fractional polynomial regression models.

CONCLUSIONS AND CLINICAL RELEVANCE ICP was positively and nonlinearly associated with increasing maximum ONSD, especially when ICP was ≤ 20 mm Hg above baseline, supporting the conclusion that ultrasonographic measurement of maximum ONSD may provide a noninvasive monitoring tool for evaluation of ICP in dogs. Further research is needed to assess the utility of these measurements in clinical patients.

Contributor Notes

Address correspondence to Dr. Thomovsky (ethomovs@purdue.edu).