The Effect of Different Concentrations of Halothane Anaesthesia on the Electroencephalograph of Rock Doves (Columba livia)

Heidi S Lehmann,Preet M Singh,Gabrielle C Musk,Kavitha Kongara,Ngaio J Beausoleil,Craig B Johnson

doi:10.3390/birds2020015

Heidi S Lehmann, Preet M Singh + Show 4 more

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https://doi.org/10.3390/birds2020015

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Abstract

Anaesthetic agents and doses used can significantly impact cerebrocortical responsiveness as assessed by electroencephalography (EEG). The objective of this study was to evaluate the effect of three different halothane concentrations on the EEG of Rock Doves using measures of frequency distribution and burst suppression. Eight healthy Rock Doves (Columba livia) were anaesthetized with halothane in oxygen, their tracheas intubated and their lungs mechanically ventilated. Five minutes of EEG were recorded at three multiples of minimum anaesthetic concentration (MAC), 1× MAC (1.6%), 1.5× MAC (2.4%) and 2× MAC (3.2%), presented in ascending then descending order. Fast Fourier transformation of the raw EEG record gave the median frequency (F50), spectral edge frequency (F95) and the total power (Ptot). Burst suppression, expressed as inactive compared to active EEG (%), was calculated on a representative two-minute section of the raw EEG. Data were analysed using repeated-measures one-way ANOVA with Tukey post hoc correction for comparison of 1×, 1.5× and 2× MAC. Three of eight birds demonstrated negligible (<1%) burst suppression. No effect of halothane concentration on burst suppression incidence was seen. A significant decrease in all measured frequency variables (F50, p = 0.04; F95p = 0.02; Ptotp < 0.0001) occurred between 1× and 2× MAC. Halothane anaesthesia at MAC multiples of 1×, 1.5× and 2× in the Rock Dove can be considered suitable where cortical responsiveness is desired.

Highlights

Electroencephalography (EEG) can be used to investigate the pain process in animals by assessing the electrical activity of the cerebral cortex in response to noxious stimulation [1]
Halothane concentration had a significant effect on the F50 (F2.7, 18.8 = 3.47, p = 0.04), F95 (F1.6, 11.6 = 6.08, p = 0.02) and Ptot (F2.2, 15.6 = 20.01, p < 0.0001) (Figure 1)
This study describes the effect of different halothane concentrations on the occurrence of burst suppression and changes in the spectral frequencies in the EEG of the Rock Dove

Summary

Introduction

Electroencephalography (EEG) can be used to investigate the pain process in animals by assessing the electrical activity of the cerebral cortex in response to noxious stimulation [1]. The raw EEG data recorded are the summation of the electrical activity occurring over time (i.e., the time domain). The three variables most used in pain and anaesthetic depth assessment are the median frequency (F50 ), below which half the total power of the EEG is located; the spectral edge frequency (F95 ), below which 95% of the total power is located; and the total power (Ptot ), the total signal power of the spectrum assessed. Certain changes in response to a noxious stimulus can be examined for their potential use as indicators of pain perception [2,3]

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