Comparison of Four Sedation and Anesthesia Protocols During Stress Radiography of the Coxofemoral Joint Using a Distension Device Modified for Force Measurements

Abstract

Chemical restraint influences canine hip dysplasia (CHD) scores for both the standard ventrodorsal hip-extended radiographs and during stress radiography. There is however no consensus on the optimal anesthesia protocol for these stress radiographs. The objective of this study was to find a sedation and/or anesthesia protocol that was safe, practical in use, and that resulted in the highest laxity index (LI), while using a validated force-measuring device. Ten Beagle dogs were randomly assigned to undergo stress radiographs under four different sedation/anesthesia protocols on three separate occasions. Sedation and anesthesia safety, ease of procedure, and LI were evaluated. Safety parameters such as temperature, heart rate, and respiratory rate remained within normal ranges for all protocols. However, one dog experienced a seizure after dexmedetomidine and ketamine sedation (protocol C). Protocol B (dexmedetomidine/butorphanol/midazolam) and protocol A (dexmedetomidine/butorphanol) scored significantly better than protocol C (dexmedetomidine/ketamine) and D (dexmedetomidine/propofol) in various aspects of safety and ease of the procedure. While the maximum laxity was similar between protocol A, B and D, only in protocol A and B a plateau phase was reached. Overall, protocol A and B performed similarly, the best scores were however consistently allocated to protocol B.  The sedation protocol dexmedetomidine, butorphanol and midazolam emerged as the most favorable sedation protocol for stress radiography of the coxofemoral joint, offering safety, practicality, and high LIs.

Keywords: Canine Hip Dysplasia, stress radiography, force measuring device, sedation, anesthesia