Equine general anesthesia monitoring – review of the methods and current knowledge

Abstract

The high anesthetic mortality rate and high number of the postanesthetic side effects in horses generates the need for precise assessment of Central Nervous System depression caused by the anesthetic agents. The factors which influence the degree of CNS depression can be human-dependent (i.e. veterinarian level of education), conditionally human-dependent (i.e. type of surgery performed) or not human-dependent (i.e. breed, individual susceptibility to anesthetics). In order to monitor and assess the level of equine anesthesia, the modified Guedel scale is used currently. There are 3 types of monitoring according to its accuracy: basic, routine and used in special cases. The monitored vital parameters can give either direct or indirect measurement on the cardiovascular and respiratory system during anesthesia. In this paper the types of measurement techniques and the practical use of ECG, pulse, eye signs, arterial blood pressure, body temperature, pulse oximetry, capnography, end tidal anesthetics concentration and blood gases were described. More parameters can be measured, but not all of them can be used in everyday practice, because of the complicated invasive technique. Currently the research are led on direct monitoring of CNS through intraanesthetic EEG analysis..