Evaluation of administration of isoflurane at approximately the minimum alveolar concentration on depression of a nociceptive withdrawal reflex evoked by transcutaneous electrical stimulation in ponies

Spadavecchia, Claudia; Levionnois, Olivier; Kronen, Peter W; Leandri, Massimo; Spadavecchia, Luciano; Schatzmann, Urs (2006). Evaluation of administration of isoflurane at approximately the minimum alveolar concentration on depression of a nociceptive withdrawal reflex evoked by transcutaneous electrical stimulation in ponies. American journal of veterinary research, 67(5), pp. 762-9. Chicago, Ill.: American Veterinary Medical Association 10.2460/ajvr.67.5.762

Full text not available from this repository. (Request a copy)

OBJECTIVE: To investigate effects of isoflurane at approximately the minimum alveolar concentration (MAC) on the nociceptive withdrawal reflex (NWR) of the forelimb of ponies as a method for quantifying anesthetic potency. ANIMALS: 7 healthy adult Shetland ponies. PROCEDURE: Individual MAC (iMAC) for isoflurane was determined for each pony. Then, effects of isoflurane administered at 0.85, 0.95, and 1.05 iMAC on the NWR were assessed. At each concentration, the NWR threshold was defined electromyographically for the common digital extensor and deltoid muscles by stimulating the digital nerve; additional electrical stimulations (3, 5, 10, 20, 30, and 40 mA) were delivered, and the evoked activity was recorded and analyzed. After the end of anesthesia, the NWR threshold was assessed in standing ponies. RESULTS: Mean +/- SD MAC of isoflurane was 1.0 +/- 0.2%. The NWR thresholds for both muscles increased significantly in a concentration-dependent manner during anesthesia, whereas they decreased in awake ponies. Significantly higher thresholds were found for the deltoid muscle, compared with thresholds for the common digital extensor muscle, in anesthetized ponies. At each iMAC tested, amplitudes of the reflex responses from both muscles increased as stimulus intensities increased from 3 to 40 mA. A concentration-dependent depression of evoked reflexes with reduction in slopes of the stimulus-response functions was detected. CONCLUSIONS AND CLINICAL RELEVANCE: Anesthetic-induced changes in sensory-motor processing in ponies anesthetized with isoflurane at concentrations of approximately 1.0 MAC can be detected by assessment of NWR. This method will permit comparison of effects of inhaled anesthetics or anesthetic combinations on spinal processing in equids.

Item Type:

Journal Article (Original Article)

Division/Institute:

05 Veterinary Medicine > Department of Clinical Veterinary Medicine (DKV) > DKV - Anaesthesiology
05 Veterinary Medicine > Department of Clinical Research and Veterinary Public Health (DCR-VPH) > Veterinary Pharmacology and Toxicology

UniBE Contributor:

Spadavecchia, Claudia; Levionnois, Olivier and Schatzmann, Urs

ISSN:

0002-9645

Publisher:

American Veterinary Medical Association

Language:

English

Submitter:

Factscience Import

Date Deposited:

04 Oct 2013 14:45

Last Modified:

04 May 2014 23:13

Publisher DOI:

10.2460/ajvr.67.5.762

PubMed ID:

16649907

Web of Science ID:

000237170800005

URI:

https://boris.unibe.ch/id/eprint/18840 (FactScience: 1086)

Actions (login required)

Edit item Edit item
Provide Feedback