The effects of medetomidine hydrochloride on the electroretinogram of normal dogs

Norman, Joanna C.; Narfström, Kristina; Barrett, Paul M.

doi:10.1111/j.1463-5224.2008.00650.x

Cited by 29 publications

(36 citation statements)

References 36 publications

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“…The combination of xylazine and butorphanol in this study, provided a good sedation and allowed adequate recording and low noise interference. No alterations were observed on ERG results due to the sedation protocol, as it may be observed when conducted with barbiturate or inhalation anesthetic agents (Norman 2008, Ekesten et al 2012.…”

Section: Discussionmentioning

confidence: 92%

Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age

et al. 2015

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Lhasa Apso dogs with immature, mature or hypermature cataracts were divided into four groups according to their age (G1: 1 to 3 years old, G2: 4 to 7 years old, G3: 8 to 11 years old, G4: more than 12 years old). All animals were evaluated under the same sedation protocol to allow the performance of the electroretinogram (ERG) exam to determine normal value of b-wave response of the full-field ERG according to age. Three ERG responses were recorded: rod, maximal and cone responses. The amplitude values and b-wave implicit time of the responses of all groups were compared and analyzed by Kruskal-Wallis test (variance analysis for non-repeated measures), followed by the Dunn post-test (when p<0,05). A significant decrease was observed in maximal responses' amplitude, when comparing the G4 group with G1 and G2. No statistically relevant differences were observed in the b-wave implicit time values between groups. The ERG values are directly influenced by the animal's age. Older patients presented a decrease in the amplitude of the maximal response. The study determined the normal parameters of ERG b-waves for Lhasa Apso dogs with cataract according to their age group.

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Section: Discussionmentioning

confidence: 92%

Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age

et al. 2015

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“…There are many variables that can influence the ERG recordings, which could be divided into two categories: physiological and instrument-related factors. While the purpose of this report is not to review those factors, physiological factors include body temperature [60] and those introduced by the protocol such as pupillary dilation [3], and the anaesthetic agent used [26,[61][62][63]. It has been recently demonstrated that injected propofol slightly influences ERG parameters during the transient injection time only [62].…”

Section: Erg and Anaesthesiamentioning

confidence: 98%

Effects of hypercapnia on the electroretinogram in sevoflurane and isoflurane anaesthetized dogs

Varela

Vazquez

González‐Cantalapiedra

et al. 2010

Doc Ophthalmol

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To evaluate the effects of induced hypercapnia on the electroretinogram (ERG) in beagle dogs anaesthetized with isoflurane and sevoflurane. Binocular, full-field flash photopic and scotopic ERGs were obtained from six healthy neutered female beagle dogs. In order to determine Vmax and the photopic negative response (PhNR), photopic ERG luminance-response curves were generated with 17 different light stimuli. Photopic flicker ERGs were obtained at 30-Hz temporal frequency. Scotopic ERGs were recorded after 35 min of dark adaptation. For all animals, this procedure was performed once in four different sessions: isoflurane + end-tidal [CO(2)] at 35 mmHg +/- 3 mmHg (ISON), isoflurane + end-tidal [CO(2)] at 65 mmHg +/- 3 mmHg (ISOH), sevoflurane + end-tidal [CO(2)] at 35 mmHg +/- 3 mmHg (SEVON), isoflurane + end-tidal [CO(2)] at 65 mmHg +/- 3 mmHg (SEVOH). In photopic conditions, b-wave amplitudes were significantly smaller in hypercapnic groups (ISON = 170.6 +/- 12.1 microV; ISOH = 132.6 +/- 24.9 microV; SEVON = 170.9 +/- 14.4 microV; SEVOH = 130.2 +/- 22.8 microV). Similarly, in scotopic conditions, b-wave amplitudes were significantly decreased when CO(2) was increased (ISON = 89.4 +/- 14.7 microV; ISOH = 58.2 +/- 17.6 microV; SEVON = 93.4 +/- 24.1 microV; SEVOH = 56.2 +/- 22.2 microV). Flicker peak times were significantly increased in hypercapnic groups (ISON = 25.9 +/- 0.4 ms; ISOH = 27.7 +/- 1.2 ms; SEVON = 25.9 +/- 1.5 ms; SEVOH = 27.2 +/- 0.7 ms). Our results clearly indicate that induced hypercapnia significantly alters the genesis of the electroretinogram at level of ON-pathway and suggest that OFF-pathway is unaffected and that ERGs obtained from isoflurane or sevoflurane anaesthetized dogs are almost identical. Control of hypercapnia must be taken into consideration when ERGs are performed under inhaled anaesthesia in dogs.

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“…Em virtude da presença de muitas variáveis, como método de registro, estímulo, adaptação ao escuro, protocolo de sedação ou anestesia que podem alterar os resultados do ERG, é indicado que cada laboratório tenha seus parâmetros de normalidade (MENTZER et al, 2006;NORMAN et al, 2008). Objetivou-se, com este estudo, padronizar os valores de normalidade da resposta de bastonetes, máxima resposta e resposta de cones em cães da raça Poodle portadores de catarata madura ou hipermadura, de acordo com a faixa etária, utilizando aparelho portátil BPM 200.…”

Section: Eletrorretinograma (Erg) é Um Meio Diagnóstico Objetivo Nãounclassified

Determinação dos valores normais do eletrorretinograma de campo total em cães da raça Poodle portadores de catarata de acordo com a faixa etária

et al. 2010

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Electroretinogram (ERG) is an objective and noninvasive diagnostic tool for the evaluation of retinal function, capable to detect early, lesions of the outermost layers in several species of animals. One of its main indications is to evaluate pre-surgical patients for cataract surgery. The determination of normal ERG values is essential if the aim is, by measuring the values; aid the diagnosis of retinal degeneration, despite of the presence of media opacity (cataract

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The effects of medetomidine hydrochloride on the electroretinogram of normal dogs

Abstract: Medetomidine significantly prolongs the implicit time and lowers the amplitude response of both the a- and b-waves in normal dogs at all flash intensities examined. Clinically, however, medetomidine only minimally affects the retinal responses and is a viable choice for use in dog ERGs.

Cited by 29 publications

References 36 publications

Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age

Normal values of b-wave responses of full-field electroretinogram in Lhasa Apso dogs with cataracts according to age

Effects of hypercapnia on the electroretinogram in sevoflurane and isoflurane anaesthetized dogs

Determinação dos valores normais do eletrorretinograma de campo total em cães da raça Poodle portadores de catarata de acordo com a faixa etária

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