This is the second of a two-part review of caudal epidural anaesthesia and analgesia in horses (CEAA). In Part 1, we provided a detailed review of the efficacy and safety of epidurally administered drugs showing that the epidural administration of many different drugs can provide effective regional anaesthesia or analgesia with only minimal side effects. In Part 2, the clinical indications and benefits of CEAA are reviewed and a detailed practical guide on how to perform an epidural injection and insert an epidural catheter is provided.
Summary
Nonspecific performance and rideability issues are more likely a manifestation of pain in the ridden horse rather than a true behavioural problem. A systematic and thorough investigation focusing on the potential presence of pain‐related conditions is thus crucial in horses with such complaints. It can, however, be challenging to determine whether the complaint is indeed related to pain, where the pain is located, and what the underlying cause is. This review describes the challenges of pain recognition in ridden horses and summarises the recently developed ridden horse ethograms that might enable pain to be assessed in an objective, valid and reliable way. Furthermore, the differential diagnosis and diagnostic approach to horses presenting potentially pain‐related performance and rideability issues are discussed.
The importance of adequate pain management in horses has gained increased clinical attention over the last decade or so, and many drugs and administration techniques have been investigated for the purpose of improving equine pain management. Caudal epidural anaesthesia and analgesia (CEAA) has the potential to be one of the most efficient techniques for management of moderate to severe pain of the pelvic limbs, the caudal part of the body and even the thoracic limbs. The epidural administration of many different drugs has been studied and clinically applied, most of them with good efficacy and minimal side-effects. In order to guide the clinician on when and how to perform CEAA in horses, this 2-part review provides a detailed review of the efficacy, safety, indications and techniques. Part 1 focuses on the efficacy and safety of epidurally administered drugs and Part 2 considers indications and contraindications, and provides a practical description on how to perform the epidural procedure.
Epidural drugsThe goal when selecting drugs for epidural injections is to achieve efficient regional anaesthesia or analgesia with appropriate onset, duration and anatomical spread, and
Summary
Caudal epidural analgesia is a well‐established therapeutic modality for pain alleviation in horses. Additionally, epidural analgesia could potentially be a complementary diagnostic tool for confirmation of pain‐related conditions in horses presenting with nonspecific signs of poor performance or rideability issues. To use the epidural as a diagnostic tool, the administered medications should provide efficient analgesia without accompanying adverse effects. Therefore, the objectives of the current study were to evaluate the analgesic properties and effects on locomotor function, mentation and physical examination parameters of caudal epidural co‐administration of methadone and morphine in horses. Five mares received a caudal epidural injection of 0.1 mg/kg bwt methadone and 0.1 mg/kg bwt morphine diluted to a total volume of 4.4 mL/100 kg. Before and several times thereafter, horses were subjected to mechanical nociceptive threshold evaluation, physical examination, assessment of mentation and locomotor function examination. Horses were assigned ataxia scores (0–4) by a group of inexperienced raters (three senior‐year veterinary students) and a group of experienced raters (two board‐certified internal medicine specialists) that assessed the locomotor examinations either live or video‐based. The epidural co‐administration of methadone and morphine resulted in clinically relevant and statistically significant increases of horses’ tolerance to mechanical noxious stimuli at the coccygeal, perineal, sacral, lumbar and thoracic regions. Analgesia was evident after 4.4 h and lasted at least 5 h. Regional differences in the onset of analgesia reflected a cranial spread of the analgesic solution. No horses showed signs of gait disturbances; the overall median ataxia score was 0 at all times; and the average difference in scores between two randomly selected raters for a random horse at a random time point was 0.377 indicating high inter‐rater agreement. There were no adverse changes of mentation and physical examination parameters. Observed side effects included signs of decreased frequency of defaecation, generalised sweating, and pruritus.
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