Analisi quantitativa elettroencefalografica in cuccioli di cane sedati con dexmedetomidina, medetomidina e dexmedetomidina associata a butorfanolo

Abstract

Electroencephalography (EEG) is a functional test that measures electrical patterns at the surface of the scalp which reflects cortical activity, and is commonly referred to as “brainwaves”. The EEG test is rarely used in veterinary medicine and can be applied in clinical practice for the epilepsy’s electro-clinical diagnosis, but also to monitor the effectiveness of its therapy and to control the depth of anesthesia or sedation during surgical or diagnostic procedures. In addition, it can be used for research purposes to study animal consciousness and its alterations produced by neurological drugs action. The aim of this work is to study the brain function of normal puppies sedated with three different anesthesiological protocols: dexmedetomidine, medetomidine and dexmedetomidine combined with butorphanol. This approach allows to define the depth of anesthesia and provide a method of comparison that allows to select the most effective drug for puppies’ sedations. This work includes 23 puppies of Argentine Dogo divided into three groups: A group (n=9) sedated puppies with dexmedetomidine, B group (n=9) sedated puppies with medetomidine and C group (n=5) sedated puppies with dexmedetomidine combined with butorphanol. We used a quantitative electroencephalographic analysis to evaluate brain function. Quantitative Electroencephalography (qEEG) is a procedure that processes the recorded EEG activity from a multi-electrode recording using a computer softwares such as MATLAB and EEGLAB (2019). The aim of this technique is to guarantee objective information on the brain activity instead of normal visual analysis of the raw EEG traces. On each subject belonging to the three groups, we calculated the power spectral density analysis of the EEG frequencies obtained. Then, for each group, we calculated the average and standard deviation of the maximum power spectral density for band expressed in µV2/ Hz. The results obtained show that the power spectral density of the EEG frequencies reaches the maximum value for the Delta frequency band in each of the three groups. During the waking state, in contrast, the maximum value is normally reached for the Beta frequency band. A background activity of low frequency and high amplitude prevails in all three groups of animals (A, B, C), confirming the theory that this condition is produced by the high degree of cortical neurons synchronization. Continuing the Theta band analysis, we observed a power spectral density slightly lower than the previous one, and much lower powers for the Alpha and Beta frequency bands. According to the data obtained, it can be concluded that the combination of dexmedetomidine and butorphanol has a more powerful sedative efficacy than the other two single protocols studied, and that dexmedetomidine has a greater activity compared to medetomidine.