Grayson A. Doss

Echocardiographic effects of dexmedetomidine-ketamine in chinchillas (Chinchilla lanigera).

Alpha2-agonist anesthetic combinations are often used in rodent anesthesia but no information about their effects on cardiac function in chinchillas exists. The purpose of this study was to utilize echocardiography to evaluate the cardiovascular effects of dexmedetomidine–ketamine anesthesia in chinchillas. Echocardiographic examinations were performed in eight adult chinchillas under manual restraint and following dexmedetomidine (0.015 mg/kg) and ketamine (4 mg/kg) administration. Dexmedetomidine–ketamine anesthesia resulted in a significantly decreased heart rate, fractional shortening, cardiac output, and flow velocity across the aortic and pulmonic valves, and significantly increased left ventricular internal diameter in systole. The observed changes in echocardiographic parameters are similar to those previously reported in chinchillas anesthetized with isoflurane.

Changes in Physiologic Parameters and Effects of Hooding in Red-tailed Hawks (Buteo jamaicensis) During Manual Restraint

Abstract Manual restraint in birds of prey is required for many veterinary and research procedures. To investigate the effects of handling stress on physiologic parameters in raptorial birds, 8 red-tailed hawks (Buteo jamaicensis) were manually restrained over a 15-minute period. Respiratory rate (RR), heart rate (HR), and cloacal temperature were monitored over time and recorded at defined intervals during the experiment. The effect of hooding on physiologic variables was also evaluated in a complete crossover design. Both RR and HR decreased significantly during the 15-minute restraint period (HR, −80 ± 101.4 beats/min [bpm], [P < .01]; RR, −17.5 ± 22.6 breaths/min, [P < .05]). Hooded birds had significantly lower HRs and RRs at 15 minutes of restraint (HR: 232.5 ± 26 bpm, [P < .037]; RR: 33.1 ± 6.7 breaths/min, [P < .05]) compared to birds restrained without a hood (HR: 280 ± 74.1 bpm; RR: 51.5 ± 28.8 breaths/min). Cloacal temperature increased significantly in all manually restrained birds (+2.2 ± 0.7°C, [P < .01]), with a comparable increase in hooded and nonhooded birds. In this study of the effects of manual restraint on red-tailed hawks, hooding versus nonhooding amplified the decrease in HR and RR but had no effect on stress-induced hyperthermia.

Urinalysis in chinchillas (Chinchilla lanigera)

OBJECTIVE To evaluate urine variables in chinchillas (Chinchilla lanigera). DESIGN Evaluation study. SAMPLE Urine samples from 41 chinchillas. PROCEDURES Voided urine samples were collected from clinically normal chinchillas that were exhibited during a breeder exposition. Urinalysis was performed within 1 hour after collection. Urine specific gravity (USG) was measured before and after centrifugation with a handheld veterinary refractometer. Urine dipstick analysis and microscopic sedimentation examination were performed on all samples. Additionally, a urine sulfosalicylic acid (SSA) precipitation test and quantitative protein analysis were performed on samples with sufficient volume. RESULTS 17 of 41 (41%) samples had a USG ≥ 1.050, and USG ranged from 1.014 to > 1.060. The USG before centrifugation did not differ significantly from that after centrifugation. Protein was detected in all urine samples on dipstick analysis. The SSA precipitation test yielded negative results for all samples tested. Results of the quantitative protein analyses were not correlated with the results of the dipstick analyses or SSA tests. The recorded pH for all samples was 8.5, which was the upper limit of detection for the reagent strip. Glucose and ketones were detected in 5 and 6 samples, respectively. Crystals were observed in 28 of 41 (68%) samples; 27 of those samples contained amorphous crystals. CONCLUSIONS AND CLINICAL RELEVANCE Urinalysis results for clinically normal chinchillas were provided. For chinchilla urine samples, measurement of USG by refractometry prior to centrifugation is acceptable and protein concentration should be determined by quantitative protein analysis rather than dipstick analysis or the SSA test.

Retrospective Evaluation of Sedation in 16 Lizard Species with Dexmedetomidine-Midazolam with or without Ketamine

Abstract A retrospective review of sedation of lizards using dexmedetomidine-midazolam (DM) with or without ketamine administered intramuscularly or subcutaneously was performed. Forty-four sedation events, involving 25 individuals and 16 different species of lizards, were reviewed. Sedation was performed for physical examinations, imaging, biopsy collection, and wound treatments. Dexmedetomidine (median: 0.08 mg/kg, 25–75%: 0.05–0.1 mg/kg, range: 0.03–0.3 mg/kg) combined with midazolam (median: 1 mg/kg, 25–75%: 0.85–1 mg/kg, range: 0.5–2 mg/kg) was used in 11/44 (25%) sedation events. In 33/44 (75%) sedation events, ketamine (median: 2.9 mg/kg, 25–75%: 2.43–3 mg/kg range: 0.9–5 mg/kg) was administered in addition to DM. Insufficient depth of sedation was reported for 2/44 (4.5%) events. Atipamezole (10 times the milligrams dose of dexmedetomidine) and flumazenil (median: 0.05 mg/kg, 25–75%: 0.05–0.05 mg/kg, range: 0.01–0.1 mg/kg) were administered for reversal of the sedative effects of DM in all sedation events. The most common complication noted was apnea, which occurred in 2/44 (4.5%) sedation events and resolved following administration of the reversal agents.

Effect of injection site on alfaxalone induced sedation in ball pythons (Python regius): Injection site snakes

OBJECTIVES To evaluate the sedative and cardiorespiratory effects of alfaxalone in ball pythons following subcutaneous administration in the cranial versus caudal third of the body. MATERIALS AND METHODS In a prospective, randomised, blinded, complete crossover study, eight ball pythons ( Python regius ) received alfaxalone in the cranial or caudal third of the body. Sedative and cardiorespiratory parameters were recorded. RESULTS Administration of alfaxalone in the cranial third of the body resulted in significantly deeper and longer sedation compared with administration in the caudal third of the body. Righting reflex was lost in five of eight snakes following cranial injection compared with one of eight snakes after caudal injection. Jaw tone was lost in all snakes following cranial injection and intubation was successfully performed in seven. In contrast, snakes did not lose jaw tone and intubation was not possible following caudal injection. Heart rate and respiratory rate were significantly decreased following administration of alfaxalone in the cranial third of the body. CLINICAL SIGNIFICANCE Administration of drugs that undergo hepatic metabolism or excretion should not be performed in the caudal third of the body in snakes, because it can result in significantly reduced drug efficacy. A hepatic first-pass effect is assumed to be the most likely underlying cause for the observed effect because part of the venous return from the caudal body flows directly to the liver.

Retrospective Evaluation of Tibiotarsal Fractures Treated With Tape Splints in Birds: 86 Cases (2006–2015)

Abstract Tibiotarsal fractures are a common presentation in small bird species and anecdotally have been reported to carry a good prognosis with proper treatment, such as external coaptation. For this retrospective study, the medical records of 5 institutions were reviewed for tibiotarsal fractures diagnosed in companion birds weighing less than 200 g. A total of 86 cases met the inclusion criteria. Cockatiels (Nymphicus hollandicus) (24/86) and budgerigars (Melopsittacus undulatus) (19/86) were the most frequently represented species. Median body weight of the birds included was 72 g (range, 16–182 g). Mid-diaphyseal (46/86) and closed (73/86) fractures with intact, deep pain sensation in the affected limb (69/76) were most frequent. A tape splint alone (79/86) or a tape splint in addition to an intramedullary pin (7/86) were applied in all cases. Median time to fracture stabilization based on palpation was 19 days (range, 7–49 days). In most cases (61/86), the initial splint applied was maintained until fracture healing was complete. A successful outcome was documented in 92% (79/86) of birds. Fractures caused by a dog or cat attack, birds presenting without deep pain sensation in the affected limb, and cases where the splint was removed before 14 days after fixation were associated with a significantly increased risk of complications, resulting in an unsuccessful outcome. The findings of this study indicated that a tape splint is an appropriate means for treatment of tibiotarsal fractures in birds weighing less than 200 g.

Effect of injection site on dexmedetomidine-ketamine induced sedation in leopard geckos (Eublepharis macularius)

OBJECTIVE To evaluate whether the sedative effects of a combination of dexmedetomidine and ketamine differed when it was administered IM in a hind limb versus a forelimb of leopard geckos (Eublepharis macularius). DESIGN Randomized crossover study. ANIMALS 9 healthy adult leopard geckos. PROCEDURES Each gecko received a combination of dexmedetomidine (0.1 mg/kg [0.045 mg/lb]) and ketamine (10 mg/kg [4.5 mg/lb]; DK), IM, in a forelimb and hind limb in a randomized order and with a 7-day interval between treatments. All geckos received atipamezole (1 mg/kg [0.45 mg/lb], SC) 45 minutes after DK administration. Palpebral and righting reflexes, jaw tone, and superficial pain and escape responses were each assessed on a 3-point scale, and the scores for those variables were summed to calculate a sedation score. Those variables and heart and respiratory rates were evaluated at predetermined times before and for 1 hour after DK administration. RESULTS For the forelimb treatment, mean sedation score was higher and mean heart rate was lower than the corresponding values for the hind limb treatment at most time points after DK administration. The righting reflex remained intact for all 9 geckos following the hind limb treatment but became absent in 7 geckos following the forelimb treatment. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that the extent of DK-induced sedation was greater when the combination was injected IM in a forelimb versus a hind limb of leopard geckos, likely owing to a hepatic first-pass effect following hind limb injection. In reptiles, IM hind limb administration of drugs that undergo hepatic metabolism and excretion is not recommended.

The Effect of Manual Restraint on Physiological Parameters in Barred Owls (Strix varia)

Abstract Manual restraint is commonly necessary when working with avian species in medical, laboratory, and field settings. Despite their prevalence, little is known about the stress response in raptorial bird species. To further understand the effect of restraint on the stress response in birds of prey, 12 barred owls (Strix varia) were manually restrained for 15 minutes. Physiological parameters (cloacal temperature, respiratory rate, heart rate) were followed over time and recorded at defined points during the restraint period. Heart rate decreased significantly over the restraint period by a mean ± SD of −73 ± 46 beats/min. Respiratory rate also decreased significantly (median: −11 breaths/min, interquartile range: −8 to −18). Cloacal temperature increased significantly over time in manually restrained owls (median: +1.5°C [+2.7°F], interquartile range: 1.3°C–2.1°C [2.3°F–3.8°F]). This study is the first to document stress hyperthermia in an owl species. Similar to another raptorial bird, the red-tailed hawk (Buteo jamaicensis), both heart rate and respiratory rate decreased and cloacal temperature increased over time in restrained barred owls. Barred owls appear to cope differently to restraint stress when compared to psittacine species.

Determination of Gastrointestinal Transit Times in Barred Owls (Strix varia) by Contrast Fluoroscopy

Abstract Contrast imaging studies are routinely performed in avian patients when an underlying abnormality of the gastrointestinal (GI) tract is suspected. Fluoroscopy offers several advantages over traditional radiography and can be performed in conscious animals with minimal stress and restraint. Although birds of prey are commonly encountered as patients, little is known about GI transit times and contrast imaging studies in these species, especially owls. Owls are commonly encountered in zoological, educational, and wildlife settings. In this study, 12 adult barred owls (Strix varia) were gavage fed a 30% weight-by-volume barium suspension (25 mL/kg body weight). Fluoroscopic exposures were recorded at 5, 15, 30, 60, 120, 180, 240, and 300 minutes after administration. Overall GI transit time and transit times of various GI organs were recorded. Median (interquartile range [IQR]) overall GI transit time was 60 minutes (IQR: 19–60 minutes) and ranged from 5–120 minutes. Ventricular and small intestinal contrast filling was rapid. Ventricular emptying was complete by a median of 60 minutes (IQR: 30–120 minutes; range: 30–240 minutes), whereas small intestinal emptying was not complete in 9/12 birds by 300 minutes. Median small intestinal contraction rate was 15 per minute (IQR: 13–16 minutes; range: 10–19 minutes). Median overall GI transit time in barred owls is more rapid than mean transit times reported for psittacine birds and red-tailed hawks (Buteo jamaicensis). Fluoroscopy is a safe, suitable method for investigating GI motility and transit in this species.