Comparative analgesic and cardiopulmonary effects of bupivacaine and ropivacaine in the epidural space of the conscious dog

Objective To compare the cardiopulmonary effects and sensory blockade of epidural bupivacaine and ropivacaine. Study Design Prospective randomized study. Animals Six young adult medium‐sized crossbred dogs weighing 25.7 ± 7.1 kg. Method Dogs were chronically implanted with a lumbosacral epidural catheter. Acepromazine sedated dogs received all treatments: 0.5% bupivacaine at 0.14 mL kg^?1 (LB5) or 0.22 mL kg^?1 (HB5); 0.5% ropivacaine at 0.14 mL kg^?1 (LR5) or 0.22 mL kg^?1 (HR5); 0.75% bupivacaine at 0.22 mL kg^?1 (HB7.5) or 0.75% ropivacaine at 0.22 mL kg^?1 (HR7.5). Loss of sensation was tested at the level of the perineum, hind toe webs, flank, and caudodorsal rib areas before injection, and post‐injection (PI) up to 150 minutes PI. Systemic arterial blood pressure and heart rate were recorded before injection, and every 10 minutes PI until 150 minutes PI. Arterial blood gas analyses were performed prior to injection, and at 30, 60 and 150 minutes PI. Results No statistical differences existed between groups for the cardiopulmonary data or time to onset of block. Group HR7.5 had lower systolic (10–70 minutes PI) and diastolic (10–70 minutes PI) blood pressures and group HR5 had lower mean (10–90 minutes PI) and diastolic (10–90 minutes PI) blood pressures compared to baseline. Heart rate was lower compared to baseline in groups LR5 and HB7.5. A significant, but mild metabolic acidosis developed in groups LR5 and HB7.5 (150 minutes PI). No differences were present for the duration of block between groups, but duration of block in the dorsocaudal rib area was shorter in group HR5 compared to HR7.5. Conclusion Epidural ropivacaine and bupivacaine at the doses used have mild effects on the cardiopulmonary system, and extent of block are similar. Clinical Relevance The 0.75% concentration of bupivacaine and ropivacaine at 0.22 mL kg^?1 appeared to contribute to greater success of block (>80%) at dermatomes L₅–L₇.     

Effect of Experience on Adrenocortical and Thyroid Responses of Arabian Horses to Gymkhana Games

Gymkhana is an equestrian event consisting of speed pattern racing and timed games for riders on horses. The aim of the study was to evaluate the effects of gymkhana competition on total cortisol and total and free iodothyronine changes in 23 Arabian purebred horses, by taking into account the effects of previous sport experience on gymkhana riding events. Compared with pre-competition values, an increase of total cortisol concentration has been observed in experienced horses at 30 minutes (P < .001) after exercise and in inexperienced horses both at 5 minutes (P < .05) and at 30 minutes (P < .01) after exercise. Compared with pre-competition values, an increase of total triiodothyronine (T₃) concentration has been observed in experienced horses at 5 minutes (P < .05) after exercise. Data obtained showed that gymkhana riding events induced differential adrenocortical and thyroid responsiveness according to previous experience of sport horses. Hence, cortisol and iodothyronine patterns may provide additional information for the monitoring of gymkhana riding performance.