Electroretinogram responses of the normal thoroughbred horse sedated with detomidine hydrochloride.
Abstract: The main objective was to record electroretinogram (ERG) parameters of normal thoroughbred mares using the HMsERG, a mini-Ganzfeld electroretinographic unit, and a contact lens electrode. The second objective was to determine whether IV detomidine hydrochloride at 0.015 mg/kg is consistently an effective choice for sedation of horses undergoing this ERG protocol. Methods: The study population consisted of 30 normal thoroughbred mares. ERG data were harvested using a protocol that included three different light intensities (10, 3000, and 10,000 mcd s/m(2)) and a 30-Hz flicker at 3000 mcd s/m(2). Results: Mean, median, standard deviation, and estimated normal ranges using the 5-95% of the data for a- and b-wave implicit times (IT), amplitudes (AMP), and b/a ratios were reported. Scotopic results at low intensity (10 mcd s/m(2)) had estimated ranges for b-wave IT of 41.8-72.9 ms and AMP of 19.8-173.3 μV. Middle intensity (3000 mcd s/m(2)) a-wave IT was 13.2-14.7 ms with a-wave AMP of 68.4-144 μV; the b-wave IT was 28.7-41.5 ms with b-wave AMP of 105.7-271.5 μV; and the b/a ratio was 0.95-2.71. The high-intensity (10,000 mcd s/m(2)) average recordings showed an a-wave IT of 13-14.9 ms, a-wave AMP of 85.7-186.8 μV; b-wave IT of 26.6-45.4 ms, b-wave AMP of 104.7-250.6 μV; and a b/a wave ratio of 0.7-2.0. The 30-Hz cone flicker showed an IT of 22.8-28.9 ms and AMP of 44.1-117.1 μV. Conclusions: Results of normal thoroughbred ERG responses are reported. The protocol proved to be simple and safe and provided consistent results.
© 2012 American College of Veterinary Ophthalmologists.
Publication Date: 2012-04-12 PubMed ID: 22498137DOI: 10.1111/j.1463-5224.2012.01022.xGoogle Scholar: Lookup
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Summary
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This research studied the average Electroretinogram (ERG) responses in normal thoroughbred horses when sedated with detomidine hydrochloride, aiming to provide data for the normal range of ERG parameters and ensuring the consistency of detomidine hydrochloride as an effective choice for sedation.
Study Design
- The main objective of the study was to record Electroretinogram (ERG) parameters of normal thoroughbred mares using specific medical instruments (an HMsERG and a contact lens electrode).
- The second aim was to see whether detomidine hydrochloride, given intravenously at a dosage of 0.015 mg/kg, was successful as a sedation method of horses undergoing the ERG protocol.
- The study used 30 horses as its sample population and applied three light intensities (10, 3000, and 10,000 mcd s/m2) on the horses as part of the ERG protocol.
Results
- ERG data was collected for a- and b-wave implicit times (IT), amplitudes (AMP), and the ratio between b-wave and a-wave (b/a ratios).
- The figures showed that for every light intensity, the b-wave IT (the time span from the starting point to the peak of the b-wave) and AMP (the maximum height of the wave produced) varied between a certain range.
- For instance, at a low light intensity of 10 mcd s/m2, the estimated ranges for b-wave IT was 41.8-72.9 ms and the AMP was 19.8-173.3 μV. Similarly, in the middle light intensity and high-intensity ERGs, the IT and AMP for both a-wave and b-wave were calculated.
- Additionally, the study also provided the b/a ratio for every ERG examined, which varied according to light intensities.
- The ERG conducted during an application of 30Hz flicker showed an IT of 22.8-28.9 ms with an AMP of 44.1-117.1 μV.
Conclusion
- The results represent a database of normal thoroughbred ERG responses, which can be vital in diagnosing potential visual deficiencies in thoroughbred mares.
- The ERG protocol proved to be applicable and safe, and it provided consistent results when the horses were sedated with detomidine hydrochloride.
Cite This Article
APA
Church ML, Norman JC.
(2012).
Electroretinogram responses of the normal thoroughbred horse sedated with detomidine hydrochloride.
Vet Ophthalmol, 15 Suppl 2, 77-83.
https://doi.org/10.1111/j.1463-5224.2012.01022.x Publication
Researcher Affiliations
- Eye Care for Animals, 13034 W Rancho Santa Fe Blvd, Suite 102, Avondale, AZ 85392, USA. mchurch@eyecareforanimals.com
MeSH Terms
- Animals
- Electroretinography / veterinary
- Female
- Horses / physiology
- Hypnotics and Sedatives / pharmacology
- Imidazoles / pharmacology
- Retina / physiology
Citations
This article has been cited 5 times.- Ignacio C, Del Mar LM, Marta B, Sina Z, Vicent R, Aloma MF. Comparison of two sedation protocols for long electroretinography in horses using the Koijman electrode. BMC Vet Res 2023 Aug 4;19(1):106.
- Vercruysse E, Naranjo C, Sauvage A, Vandersmissen M, Grauwels M, Monclin S. Retinal detachment secondary to vitreoretinopathy in two closely related warmblood horses. Open Vet J 2021 Oct-Dec;11(4):672-679.
- Kim BG, Chang IB, Jeong KD, Park JY, Kim JS, Hwang JH. Comparison of electroretinographic measurements between tabletop and handheld stimulators in healthy subjects. Doc Ophthalmol 2019 Aug;139(1):1-9.
- Lapkovska A, Palmowski-Wolfe AM, Todorova MG. Comparing DTL microfiber and Neuroline skin electrode in the Mini Ganzfeld ERG. BMC Ophthalmol 2016 Aug 5;16:137.
- Ström L, Ekesten B. Visual evoked potentials in the horse. BMC Vet Res 2016 Jun 21;12(1):120.
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