Equine Anaesthesia

• Explain the importance of performing a pre-anaesthetic evaluation
• Give examples of how the health status of the patient may influence the outcome of general anaesthesia (see also modules 7 and 8)
• Perform a physical examination of a horse for the purpose of pre-anaesthetic evaluation (practical)
• Evaluate physical examination findings and laboratory data in order to formulate an anaesthetic/analgesic plan 2.5 Recognise how a surgical procedure may influence the formulation of an anaesthetic/analgesic plan
• Define the general pharmacological aspects of the common pre-medication, injectable and inhalational anaesthetic agents
• Define the differences between the various classes of pre-medication and injectable agents
• Define the concept of minimum alveolar concentration and how to employ this knowledge with respect to general anaesthesia in the horse 2.9 Hypothesise an ideal combination of pre-medication and injectable agents that justify their use in various different pathological disease states in the horse
• Compare and contrast the various different inhalational anaesthetic agents and how these differences influence the management of general anaesthesia in the horse
• Identify the procedures necessary to prepare a horse for anaesthesia, employ the common methods of inducing general anaesthesia of the horse and describe how to position a horse on a surgical table so as to minimise injury to the horse
• Compare and contrast the various methods used to recover a horse, e.g. unassisted, head and rope recovery, mat recovery, sling recovery, pool recovery etc

• Discuss the physiology and pathophysiology of pain in terms of transduction, transmission, modulation and perception
• Define the following terms; nociception, primary and secondary hyperalgesia, peripheral and central sensitisation, adaptive and maladaptive pain
• Describe how pharmacological agents modify the four processes of the pain pathways 4.4 Define the general pharmacological aspects of the commonly used analgesic agents, e.g. mechanism of action, onset time, duration of action, dose rate, drug interactions, adverse effects and contraindications
• Assist the veterinary surgeon in formulating an individualised analgesic plan that compensates for the differing pathophysiology of each horse
• Recognise the different pain behaviours in horses and be able to categorise these behaviours as mild, moderate or severe 4.7 Assist the veterinary surgeon in formulating an analgesic plan that is appropriate for the level of nociception/pain of an individual horse
• Discuss in general terms the limitations of each of the different pain scoring systems currently in use

• Identify the key components of a large animal anaesthetic machine and ventilator
• Describe the functionality of each component of a large animal anaesthetic machine, including the ventilator and scavenging system
• Perform a leak test and evaluate a large animal anaesthetic machine for safety from both a patient and personnel perspective (practical)
• Identify common faults with the functionality of a large animal anaesthetic machine, ventilator and scavenging system (practical)1.3 Describe how to use a large animal anaesthetic machine, e.g. how to manipulate the anaesthetic depth during anaesthesia
• Compare and contrast the functionality of a large animal anaesthetic machine with a small animal anaesthetic machine 1.7 Explain the cardiovascular and respiratory effect of positive pressure ventilation in both normovolaemic and hypovolaemic horses
• Apply the physiological effects of positive pressure ventilation on how to manage mechanical ventilation in a horse with pathological states, e.g. colic, respiratory disease etc.

• Identify the various monitoring modalities available that are commonly used during general anaesthesia of the horse
• Describe the basic mode of operation of the various monitoring modalities, e.g. electrocardiography, pulse oximetry, blood pressure monitoring, capnography, temperature probes and gas analysers
• Explain how each modality can be used to measure oxygen delivery
• Describe the limitations of each modality and how these limitations may impact the monitoring of general anaesthesia in the horse 3.5 Employ and operate these monitoring modalities during the anaesthesia of a horse (practical)
• Identify the commonly seen bradydysrhythmias and tachydysrhythmias of horses
• Interpret the results of blood pressure monitoring and how the blood pressure waveform can be used to assess heart rate, rhythm, inotropy and pulse pressure variability
• Demonstrate how to set up and test a direct blood pressure monitoring line (practical) 3.9 Illustrate in graphical terms the concept of signal damping and natural resonance as it pertains to arterial waveforms
• Discuss in general terms how to optimise the signal from an arterial waveform
• Identify and interpret the commonly seen capnograms during anaesthesia in the horse and modify the anaesthesia in response to these abnormalities
• Interpret common blood gas abnormalities and explain how to treat them

• Describe the various types of intravenous fluids available for use in the horse, e.g. crystalloids, colloids and blood products
• Explain the basics of the physiology of fluid balance in the horse in terms of Starling’s fluid equation
• Assist the veterinary surgeon in devising a fluid therapy plan based upon this physiology and monitor the response to fluid therapy in the horse 5.4 Explain in general terms the different blood types of horses and the clinical implications of these, including how to perform a cross-match
• Discuss the indications for use of the various blood products available for circulatory support in the horse, e.g. fresh whole blood, whole blood, fresh frozen plasma, frozen plasma, cryosupernatant, cryoprecipitant etc.
• Demonstrate how to use blood products in an appropriate manner, including the collection of blood from a donor horse 5.7 Interpret the clinical signs of a horse responding to blood products to include the signs of adverse reactions
• Explain the importance of nutritional support for horses undergoing anaesthesia
• Demonstrate how to provide nutritional support for horses during the peri-anaesthetic period

• Define the general pharmacological aspects of local anaesthetic agents e.g. mechanism of action, onset time, duration of action, dose rate, adverse effects and contraindications
• Describe and demonstrate the common local anaesthetic techniques of the head and coccygeal epidural (practical)
• Identify and interpret clinical signs of the following anaesthetic complications; hypothermia, bradydysrhythmias, tachydysrhythmias, hypotension, hypertension, hypoxaemia, hypercapnia and rebreathing of CO2 6.4 Formulate a differential diagnoses list for each of the anaesthetic complications listed above
• Develop a clinical approach to the treatment of each of the anaesthetic complications listed above 6.6 Describe basic and advanced life support techniques used in horses
• Summarise the current scientific literature using the RECOVER guidelines

• Discuss the anaesthetic considerations for performing anaesthesia in an operating room
• Summarise the special anaesthetic considerations for common soft-tissue and orthopaedic conditions, e.g. management of induction, use of modified intubation techniques, positioning, different recovery techniques
• Discuss the anaesthetic considerations for performing anaesthesia in the field 7.4 Compare and contrast the anaesthetic management of donkeys and mules as compared to horses

• Discuss the anaesthetic considerations for performing anaesthesia in the foal
• Discuss the anaesthetic considerations for performing anaesthesia in the pregnant mare, including the anaesthetic management of a mare with dystocia
• Discuss the anaesthetic considerations for performing anaesthesia in the horse with colic
• Summarise the special considerations for performing anaesthesia in the compromised horse with cardiac disease, respiratory disease, renal disease and liver disease

• Perform a leak test and evaluate a large animal anaesthetic machine for safety from both a patient and personnel perspective (practical)
• Identify common faults with the functionality of a large animal anaesthetic machine, ventilator and scavenging system (practical)

Other learning outcomes covered within the practical elements consist of:

• Considerations for anaesthesia in the field
• Performing anaesthesia in an operating room
• The different devices available for monitoring anaesthesia in the horse
• Modes of operation of the various monitoring modalities
• The measurement of oxygen delivery and blood pressure
• Commonly seen bradydysrhythmias and tachydysrhythmias of horses
• The use of arterial waveforms and capnograms in monitoring anaesthesia
• The principles of pre-anaesthestic assessments
• The large animal anaesthetic machine key components and functionality
• Ventilators key components and functionality

• Local anaesthetic techniques of the head and coccygeal epidural
• Life support techniques in horses
• The RECOVER guidelines