Levionnois, O. L.; Spadavecchia, C.; Kronen, P.W.; Schatzmann, U. (2009). Determination of the minimum alveolar concentration of isoflurane in Shetland ponies using constant current or constant voltage electrical stimulation. Veterinary anaesthesia and analgesia, 36(1), pp. 9-17. Oxford: Blackwell Science 10.1111/j.1467-2995.2008.00420.x
Full text not available from this repository.OBJECTIVE: To determine the minimum alveolar concentration (MAC) of isoflurane in Shetland ponies using a sequence of three different supramaximal noxious stimulations at each tested concentration of isoflurane rather than a single stimulation. STUDY DESIGN: Prospective, experimental trial. ANIMALS: Seven 4-year-old, gelding Shetland ponies. METHODS: The MAC of isoflurane was determined for each pony. Three different modes of electrical stimulation were applied consecutively (2 minute intervals): two using constant voltage (90 V) on the gingiva via needle- (CVneedle) or surface-electrodes (CVsurface) and one using constant current (CC; 40 mA) via surface electrodes applied to the skin over the digital nerve. The ability to clearly interpret the responses as positive, the latency of the evoked responses and the inter-electrode resistance were recorded for each stimulus. RESULTS: Individual isoflurane MAC (%) values ranged from 0.60 to 1.17 with a mean (+/-SD) of 0.97 (+/-0.17). The responses were more clearly interpreted with CC, but did not reach statistical significance. The CVsurface mode produced responses with a longer delay. The CVneedle mode was accompanied by variable inter-electrode resistances resulting in uncontrolled stimulus intensity. At 0.9 MAC, the third stimulation induced more positive responses than the first stimulation, independent of the mode of stimulation used. CONCLUSIONS: The MAC of isoflurane in the Shetland ponies was lower than expected with considerable variability among individuals. Constant current surface electrode stimulations were the most repeatable. A summation over the sequence of three supramaximal stimulations was observed around 0.9 MAC. CLINICAL RELEVANCE: The possibility that Shetland ponies require less isoflurane than horses needs further investigation. Constant current surface-electrode stimulations were the most repeatable. Repetitive supramaximal stimuli may have evoked movements at isoflurane concentrations that provide immobility when single supramaximal stimulation was applied.
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 Veterinary Medicine (DKV) |
UniBE Contributor: |
Levionnois, Olivier, Spadavecchia, Claudia, Schatzmann, Urs |
Subjects: |
600 Technology > 630 Agriculture |
ISSN: |
1467-2987 |
Publisher: |
Blackwell Science |
Language: |
English |
Submitter: |
Factscience Import |
Date Deposited: |
04 Oct 2013 15:25 |
Last Modified: |
17 Apr 2024 16:50 |
Publisher DOI: |
10.1111/j.1467-2995.2008.00420.x |
Web of Science ID: |
000261685800002 |
URI: |
https://boris.unibe.ch/id/eprint/38395 (FactScience: 221287) |
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