Preliminary Study of the Use of Root with Sedline® EEG Monitoring for Assessment of Anesthesia Depth in 6 Horses

Abstract

Management of equine anesthesia monitoring is still a challenge. Careful monitoring to provide guidelines for anesthesia depth assessment currently relies upon eye signs, cardiopulmonary responses, and the level of muscle relaxation. Electroencephalography, as a non-invasive brain activity monitor, may be used to complement the routinely monitored physiologic parameters. Six horses, undergoing various surgical procedures and anesthesia protocols, were monitored with the use of a Root with Sedline EEG monitor and a routine monitor of life parameters. The life parameters were compared to the changes on the EEG density spectral array observed live during anesthesia. During all procedures the level of awareness was monitored using the EEG, with higher frequency and power of waves indicating a higher level of awareness. It was evident from this that there were variations according to the type of procedure and the anesthetic protocol. Cerebral activity was elevated during painful moments of the surgery and recovery, requiring adjustments in anesthetic concentrations. Evaluation of changes in the spectral edge frequency (SEF) could show the periods when the patient is stabilized. EEG monitoring has the potential to be used in clinical anesthesiology of horses. It was shown that this system may be used in horses under general anesthesia but is currently less effective in a standing horse for diagnostic or minor procedures.

Usability of the SedLine® electroencephalographic monitor of depth of anaesthesia in pigs: a pilot study

“…3b, c, d) ◂ skin is further prepared with soap and abrasive paper. This is in contrast with what reported by Drewnowska et al [19], which used the RD SedLine® EEG-sensor in horses without previously shaving the hair, but applying tape bandaging to maintain a good contact over time.…”

Limited usefulness of the observation of eye bulb rotation and neuro-ophthalmic responses for assessing the depth of equine anesthesia: an observational study comparing three protocols

“…Moreover, the measurement of brain activity could be of great value. The power spectral analysis of the EEG has been used to evaluate brain responses to anesthetic protocols in horses (6)(7)(8)25). Likewise, the bispectral index (BIS) has been used to evaluate brain responses during inhalant anesthesia (34).…”

Perioperative Brain Function Monitoring with Electroencephalography in Horses Anesthetized with Multimodal Balanced Anesthetic Protocol Subjected to Surgeries

“…The positions of the needle electrodes were similar to those described in Drewnowska et al [ 34 ], with the position of the electrode corresponding to the position of the human EEG 10–20 system, the Sedline ® electrode R1 positioned at the Fp2, R2 positioned between F4–F8, L1 positioned at the Fp1, and L2 positioned between F3 and F7. The ground (CB) and the reference (CT) electrodes were placed on the mid-sagittal line in the central and the caudal position, respectively (see Figure 1 ).…”

“…The routine use of EEG for monitoring brain function has not gained significant acceptance in equine anesthesia. Although the use of EEG for monitoring the depth of anesthesia in horses has been previously attempted with bispectral index monitoring [ 7 , 11 , 16 , 18 , 20 , 26 , 34 , 35 , 36 ], the results were not optimum, and were at times confusing.…”

“…Therefore, it is unknown whether the use of Sedline ® monitors can reproduce those results observed in human studies. The use of Sedline ® monitors in horses and pigs has been recently explored [ 22 , 34 , 35 ]. Exploring a routine and easy-to-use continuous EEG monitoring system as an adjunct to the current cardiorespiratory monitoring in equine anesthesia is a worthwhile endeavor in order to improve the anesthetic safety in a species that has a high risk of morbidity and mortality while undergoing and recovering from general anesthesia.…”