Monitoring techniques for equine anaesthesia

Abstract

SummaryThe anaesthetist aims to preserve normal physiology of the horse notwithstanding the use of general anaesthetic drugs and pre‐existing pathological changes. Provision of analgesia and maintaining an adequate plane of anaesthesia are important alongside monitoring cardiorespiratory performance, response to noxious stimuli and temperature. There are a variety of techniques that subjectively or objectively assess physiological variables, and the results should be interpreted in the context of the anaesthetic protocol. Basic ‘hands‐on’ monitoring of anaesthesia requires no equipment and is a core skill for every anaesthetist. However, as technology advances, many more electronic monitoring options have become available. This review describes how to use specific monitoring techniques, discusses the evidence underpinning them and evaluates their place in clinical practice. Where appropriate, normal and abnormal values are highlighted, although evaluation of trends may be more important in some cases. Regular documentation of variables enables trends to be identified and is key to appropriate early intervention. All basic monitoring techniques that require no equipment, such as ocular and mucous membrane assessment and pulse palpation, are recommended for every general anaesthetic procedure. The use of capnography, pulse oximetry, electrocardiography and blood pressure monitoring devices is recommended where indicated (Martinez et al., 2008), recognising that anaesthesia in horses is performed in a variety of places with different facilities and using various drug combinations.