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Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001)2021; 31(3); 315-322; doi: 10.1111/vec.13061

Evaluation of transpalpebral ultrasonographic measurement of optic nerve sheath diameter for indirect assessment of intracranial pressure in anesthetized and standing healthy adult horses.

Abstract: To determine whether an association exists between direct intracranial pressure (ICP) measurement and ultrasonographic measurement of optic nerve sheath diameter (ONSD) in anesthetized and standing horses. Methods: Cross-sectional study performed on a convenience sample of healthy adult horses. Methods: University teaching hospital. Methods: Eight adult horses donated to the University. Enrolled horses were free of abnormalities on physical examination, CBC, neurological evaluation, and ophthalmological examination. Results: Horses were anesthetized in lateral recumbency for placement of an ICP transducer. Three head positions (neutral, elevated, and lowered) were used to alter ICP. ICP and ONSD in 2 directions (D1 and D2) were recorded at 5 and 10 minutes after position change to elevated and lowered. ICP and ONSD measurements were repeated in standing sedated horses 24-36 hours after recovery from anesthesia. Linear regressions were performed with ICP as the dependent variable and ONSD as the independent variable by head position and times. Linear regressions were also performed for change from neutral under anesthesia, with ONSD as the independent variable and ICP as the dependent variable, by head position and times. Significance was set at P < 0.05. There was a moderate association between ICP and ONSD in horses with head lowered at 5 and 10 minutes (R values = 63%-78%) and weak association in head elevated at 10 minutes (R values = 56%-63%). There was a weak association between change from neutral ICP and change from neutral ONSD in the elevated anesthetized position at 10 minutes for summed D1 + D2 (R  = 33%). Conclusions: Consistent associations between direct ICP and ONSD in anesthetized or standing horses were not observed. This inconsistency limits the clinically utility of transpalpebral ultrasonographic ONSD measurement for ICP monitoring in horses.
© Veterinary Emergency and Critical Care Society 2021.
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Publication Date: 2021-04-27 PubMed ID: 33905179DOI: 10.1111/vec.13061Google Scholar: Lookup
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  • Evaluation Study
  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research aimed to explore if there’s any correlation between direct intracranial pressure (ICP) measurement and ultrasonographic measurement of optic nerve sheath diameter (ONSD) in anesthetized and standing horses. However, it concluded that the inconsistency of this association hampers its clinical use in monitoring ICP in horses through non-invasive ultrasonographic ONSD measurement.

Study Methodology

  • The study was cross-sectional in nature and carried out on eight adult horses donated to a university teaching hospital. These horses were selected as they showed no abnormalities during physical examination, complete blood count (CBC), neurological evaluation, and ophthalmological inspection.
  • The experiment was conducted under anesthesia with the horses lying on their sides (lateral recumbency) for the placement of an ICP transducer. ICP and ONSD measurements were taken in three different head positions: neutral, elevated, and lowered. The horses’ ICP and ONSD were recorded 5 and 10 minutes after elevating and lowering their heads.
  • Further, these measurements were repeated 24-36 hours after the horses recovered from anesthesia, but this time when they were standing and sedated.

Data Analysis and Findings

  • Data was analyzed using linear regressions, keeping ICP as the dependent variable and ONSD as the independent variable. These regressions were evaluated for each head position and at different time intervals.
  • Statistical significance was set at P < 0.05. If P was less than this threshold, it means the relationship was acknowledged as significant.
  • Modest correlation between ICP and ONSD was seen in horses with the head lowered at 5 and 10 minutes, while a weak correlation was observed in those with elevated heads at the 10-minute mark.
  • No strong association was found between the variation from neutral ICP and variation from neutral ONSD in horses with their heads elevated at the 10-minute mark post anesthesia.
  • The study concluded that strong, consistent correlations between directly measured ICP and ultrasonographically measured ONSD in anesthetized or standing horses were not observed. The inconsistency noted substantially restricts the clinical utility of this non-invasive method for ICP monitoring in horses.

Conclusion

  • The research aimed to provide an alternative, less invasive method to monitor ICP in horses. It attempted to establish a correlation between the directly measured ICP and ultrasonographically determined ONSD. However, the results showed weak to modest associations, limiting its practical implementation due to the noted inconsistency.

Cite This Article

APA
Bramski JH, Reed RA, Diehl KA, Epstein KL, Ryan CA. (2021). Evaluation of transpalpebral ultrasonographic measurement of optic nerve sheath diameter for indirect assessment of intracranial pressure in anesthetized and standing healthy adult horses. J Vet Emerg Crit Care (San Antonio), 31(3), 315-322. https://doi.org/10.1111/vec.13061

Publication

Journal of veterinary emergency and critical care (San Antonio, Tex. : 2001)
ISSN: 1476-4431
NlmUniqueID: 101152804
Country: United States
Language: English
Volume: 31
Issue: 3
Pages: 315-322

Researcher Affiliations

Bramski, Jessica H
  • Department of Large Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.
Reed, Rachel A
  • Department of Large Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.
Diehl, Kathryn A
  • Department of Small Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.
Epstein, Kira L
  • Department of Large Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.
Ryan, Clare A
  • Department of Large Animal Medicine, College of Veterinary Medicine, The University of Georgia, Athens, Georgia, USA.

MeSH Terms

  • Animals
  • Cross-Sectional Studies
  • Female
  • Horse Diseases / diagnostic imaging
  • Horses
  • Intracranial Hypertension / diagnostic imaging
  • Intracranial Hypertension / veterinary
  • Intracranial Pressure / physiology
  • Male
  • Monitoring, Physiologic / methods
  • Monitoring, Physiologic / veterinary
  • Optic Nerve / diagnostic imaging
  • Prospective Studies
  • Ultrasonography / methods
  • Ultrasonography / veterinary

Grant Funding

  • University of Georgia Love of the Horse Research Endowment

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Citations

This article has been cited 3 times.
  1. Mitchell KG, Appleby RB, Sinclair MD, Singh A. The effect of laparoscopy on intracranial pressure as measured by optic nerve sheath diameter: A review. Can Vet J 2022 Apr;63(4):416-421.
    pubmed: 35368391
  2. Vitiello L, De Bernardo M, Capasso L, Cornetta P, Rosa N. Optic Nerve Ultrasound Evaluation in Animals and Normal Subjects. Front Med (Lausanne) 2021;8:797018.
    doi: 10.3389/fmed.2021.797018pubmed: 35071277google scholar: lookup
  3. Valerio-López CM, Murthy VD, Hoehne SN, Mattoon J, Chen AV. Comparison of Ultrasonographic Optic Nerve Sheath Diameter Before and After Mannitol Administration in Dogs With Presumed Intracranial Hypertension. J Vet Emerg Crit Care (San Antonio) 2025 Nov-Dec;35(6):672-680.
    doi: 10.1111/vec.70069pubmed: 41313647google scholar: lookup
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