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Objective Describe the pharmacokinetics and pharmacodynamics of intravenous hydromorphone in healthy horses. Study design Masked, randomized, cross-over, Latin square design. Animals A group of eight healthy adult horses Methods Horses were administered each of four treatments with an 8 day washout. Treatments groups included intravenous hydromorphone 0.02 mg kg–1 (LD), 0.04 mg kg–1 (MD), 0.08 mg kg–1 (HD) and saline (P). Blood samples for hydromorphone analysis were obtained for 24 hours after treatment. Plasma hydromorphone was quantified and pharmacokinetic parameters were determined using non-compartmental analysis. Pharmacodynamic data collected for 24 hours after treatment included thermal nociceptive threshold, heart rate (HR), respiratory rate (fR) and rectal temperature, and analyzed using mixed-effects linear models. Results Mean (± standard deviation) hydromorphone terminal half-life (t1/2), systemic clearance and apparent volume of distribution at steady state (Vdss) were 18.1 ± 18.6, 34.0 ± 12.8, and 41.3 ± 32.5 minutes, 66.6 ± 5.3, 550.0 ± 76.4, and 92.7 ± 13.9 mL kg–1 minute–1, and 1118 ± 369, 1460 ± 325 and 2242 ± 950 mL kg–1 for treatments LD, MD and HD, respectively. Thermal threshold increased significantly compared to baseline for all treatments for up to 12 hours. HR was elevated above baseline in treatments LD, MD and HD, extending to 30, 15 and 105 minutes after treatment, respectively. Respiratory rate was elevated above baseline in treatments MD and HD from 30 to 195 minutes and from 45 to 480 minutes after treatment, respectively. Temperature was elevated above baseline in treatment HD until 255 minutes after treatment. Conclusions Hydromorphone exhibited a short t1/2, rapid clearance and large Vdss in horses. It also provided a dose-dependent increase in thermal threshold with associated increases in HR, fR and rectal temperature. Clinical relevance Hydromorphone 0.04 mg kg–1 provided clinically relevant thermal antinociception with minimal adverse effects.

Objective To compare oxygenation and ventilation in white-tailed deer (Odocoileus virginianus) anesthetized with two treatments with and without oxygen supplementation. Study design Randomized, blinded, crossover study. Animals A total of eight healthy adult white-tailed deer weighing 49–62 kg. Methods Each deer was anesthetized twice intramuscularly: 1) treatment XK, xylazine (2 mg kg–1) and ketamine (6 mg kg–1) and 2) treatment XTZ, xylazine (2 mg kg–1) and tiletamine–zolazepam (4 mg kg–1). With the deer in sternal position, arterial and venous blood was collected before and at 30 minutes during administration of oxygen at 1 L minute–1 through a face mask. PaO2 and heart rate (HR) were compared using two-way repeated measures anova . pH, PaCO2 and lactate concentration were analyzed using mixed-effects linear models, p Results When breathing air, PaO2 was Conclusions and clinical relevance Treatments XK and XTZ resulted in hypoxemia, which responded to oxygen supplementation. Both treatments are suitable for immobilization of white-tailed deer under the study circumstances.

The usefulness of pre-anesthetic laboratory screening of healthy veterinary patients is controversial and clear evidence-based guidelines do not exist. The purpose of our study was to determine the influence of preanesthetic laboratory screening on peri-anesthetic plans in canine patients undergoing elective surgery. One hundred medical records were randomly selected between the years 2008 and 2013 and patient information was presented to 5 Diplomates of the American College of Veterinary Anesthesia and Analgesia (ACVAA) for review. They were given pre-anesthetic laboratory screening test results for each patient and asked whether the results would change the way they managed the case from an anesthesia perspective. Peri-operative anesthetic management was altered in 79% of patients based on pre-anesthetic screening results; however, the overall agreement among anesthesiologists was weak with 64% of changes made by only a single anesthesiologist. Pre-anesthetic laboratory screening test results may influence pre-operative anesthesia case management but major discrepancies can occur among ACVAA diplomates.