Pharmacokinetics of hydrorphone hydrochloride after intravenous and subcutaneous administration in ferrets (Mustela putorius furo).

OBJECTIVE: To determine the pharmacokinetic profile of hydromorphone 0.2 mg kg-1 administered by the intravenous (IV) and subcutaneous (SC) route in ferrets. STUDY DESIGN: Randomized, crossover study. ANIMALS: A group of eight adult ferrets weighting (mean ± standard deviation) 1.02 ± 0.22 kg. METHODS: Hydromorphone hydrochloride 0.2 mg kg-1 was administered IV or SC with a washout period of 7 days. Blood samples were collected from a jugular catheter before administration of hydromorphone and at 5, 10, 15, 20, 30, 45, 60, 90, 120, 240, 360, 480 and 720 minutes after hydromorphone administration. Plasma hydromorphone concentrations were determined by liquid chromatography/tandem mass spectrometry. Data were analyzed using a non-linear mixed effects model. RESULTS: The hydromorphone effective half-life was (t1/2) 45 min-1. Systemic clearance (Cls) and the volume of distribution (Vdss) following IV administration were 84.8 mL kg-1 min-1 and 5.59 L kg-1, respectively. The maximum observed plasma concentration was 59.53 ± 14.02 ng mL-1 within 10 minutes following SC administration. The SC bioavailability was 102.0%. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of IV and SC hydromorphone (0.2 mg kg-1) was characterized by a high clearance, short terminal half-life and large volume of distribution. Hydromorphone plasma concentrations remained greater than 2 ng mL-1 for 2 hours in most ferrets, a threshold reported to provide antinociceptive effects in other species. Hydromorphone was well absorbed following SC injection, providing an alternative administration route for clinical use in ferrets.

Comparison between mainstream (Capnostat 5) and a low-flow sidestream capnometer (Capnostream) in mechanically ventilated, sevoflurane-anesthetized rabbits using a Bain coaxial delivery system.

OBJECTIVE: To evaluate agreement between end-tidal carbon dioxide (Pe'CO2) and PaCO2 with sidestream and mainstream capnometers in mechanically ventilated anesthetized rabbits, with two ventilatory strategies. STUDY DESIGN: Prospective experimental study. ANIMALS: A total of 10 New Zealand White rabbits weighing 3.6 ± 0.3 kg (mean ± standard deviation). METHODS: Rabbits anesthetized with sevoflurane were intubated with an uncuffed endotracheal tube (3.0 mm internal diameter) and adequate seal. For Pe'CO2, the sidestream capnometer sampling adapter or the mainstream capnometer was placed between the endotracheal tube and Bain breathing system (1.5 L minute-1 oxygen). PaCO2 was obtained from arterial blood collected every 5 minutes. A time-cycled ventilator delivered an inspiratory time of 1 second and 12 or 20 breaths minute-1. Peak inspiratory pressure was initially set to achieve Pe'CO2 normocapnia of 35-45 mmHg (4.6-6.0 kPa). A total of five paired Pe'CO2 and PaCO2 measurements were obtained with each ventilation mode for each capnometer. Anesthetic episodes were separated by 7 days. Agreement was assessed using Bland-Altman analysis and linear mixed models; p < 0.05. RESULTS: There were 90 and 83 pairs for the mainstream and sidestream capnometers, respectively. The mainstream capnometer underestimated PaCO2 by 12.6 ± 2.9 mmHg (proportional bias 0.44 ± 0.06 mmHg per 1 mmHg PaCO2 increase). With the sidestream capnometer, ventilation mode had a significant effect on Pe'CO2. At 12 breaths minute-1, Pe'CO2 underestimated PaCO2 by 23.9 ± 8.2 mmHg (proportional bias: 0.81 ± 0.18 mmHg per 1 mmHg PaCO2 increase). At 20 breaths minute-1, Pe'CO2 underestimated PaCO2 by 38.8 ± 5.0 mmHg (proportional bias 1.13 ± 0.10 mmHg per 1 mmHg PaCO2 increase). CONCLUSIONS AND CLINICAL RELEVANCE: Both capnometers underestimated PaCO2. The sidestream capnometer underestimated PaCO2 more than the mainstream capnometer, and was affected by ventilation mode.

Agreement of caudal aortic arterial blood pressure with oscillometry using two cuff widths placed on the thoracic or pelvic limbs of sevoflurane-anesthetized rabbits.

OBJECTIVE: To evaluate agreement with central systemic arterial pressure of an oscillometer and two cuff widths placed on the thoracic or pelvic limbs. STUDY DESIGN: Prospective experimental study. ANIMALS: A group of nine New Zealand White rabbits weighing 3.5 ± 0.3 kg. METHODS: Rabbits were sedated with dexmedetomidine and midazolam, then anesthetized with ketamine and sevoflurane. The femoral artery was surgically exposed and a 20 gauge, 5 cm catheter inserted to measure systolic (SAP), mean (MAP) and diastolic (DAP) blood pressure at the iliac artery and caudal aorta junction. Adjustments of vaporizer dial and dobutamine infusion provided a range of invasive blood pressure (IBP). Two measurements of IBP were recorded during the oscillometer cycling phase, and the mean value was used in analyses. Oscillometer cuffs of bladder width 2.0 cm (S1) and 2.5 cm (S2) were placed proximal to the carpus and tarsus. Cuff width to circumference ratio was calculated. Oscillometer SAP, MAP and DAP were paired with corresponding IBP values. Agreement was assessed using linear mixed models (p < 0.05). RESULTS: Cuff ratios for both limbs were 41% (S1 cuff) and 50% (S2 cuff) and 122-139 paired observations were obtained. There was significant limb × cuff interaction with SAP and MAP. The oscillometer overestimated SAP and MAP on the pelvic limb and underestimated SAP and MAP on the thoracic limb. For SAP, the oscillometer overestimated by constant bias (-19 ± 2 mmHg) and proportional bias (0.28 ± 0.02 mmHg per 1 mmHg increase). For MAP, the oscillometer underestimated by constant bias (4 ± 2 mmHg) and was worse with S2 on the thoracic limb. Overestimation was similar between cuffs on the pelvic limb. For DAP, the oscillometer underestimated by constant bias (15 ± 2 mmHg). CONCLUSIONS AND CLINICAL RELEVANCE: Cuff S1 on the thoracic limb provided best estimation of MAP.

Radiographic appearance of a caudal vertebral chordoma in a domestic ferret (Mustela putorius furo).

A 7-year-old spayed female ferret was presented to the Veterinary Teaching Hospital at the Western College of Veterinary Medicine for a slow-growing mass involving the base of the tail. Radiographs revealed a large, irregularly marginated mineralized mass centered on the fifth to seventh caudal vertebrae with osteolysis of the affected caudal vertebrae. A partial caudectomy was performed, and histopathology was consistent with a chordoma. This is the first case report describing the radiographic appearance of a chordoma in the proximal tail and only the second report to describe radiographic findings in a ferret.

Effect of preoxygenation before isoflurane induction and rocuronium-induced apnea on time until hemoglobin desaturation in domestic chickens (Gallus gallus domesticus).

OBJECTIVE: To evaluate the time to hemoglobin oxygen desaturation in chickens (Gallus gallus domesticus) with and without preoxygenation before isoflurane induction of anesthesia and rocuronium-induced apnea. STUDY DESIGN: Prospective, randomized crossover study. ANIMALS: A total of 10 healthy adult Lohmann Brown-Lite hens. METHODS: Hens were anesthetized with isoflurane for intravenous (IV) and intraarterial catheter placement and allowed to fully recover from anesthesia. Hens in the preoxygenation treatment were administered oxygen (2 L minute-1) via a facemask for 3 minutes prior to induction of anesthesia with 3% isoflurane in oxygen. In the alternative treatment, hens were not preoxygenated prior to induction of anesthesia with isoflurane in oxygen. Apnea was then induced with rocuronium bromide (1.0 mg kg-1) administered IV, and anesthesia was maintained with IV propofol infusion. A cloacal pulse oximeter measured hemoglobin oxygen saturation (SpO2). Time was recorded from the start of apnea until SpO2 was 90% (desaturation). The trachea was intubated, and anesthesia was maintained with isoflurane in oxygen with manual ventilation until spontaneous breathing returned and SpO2 ≥ 99%. PaO2 was measured before each treatment, after preoxygenation, postinduction and at desaturation. Data were analyzed between treatments using Wilcoxon matched-pairs signed rank tests with Holm-Sidák multiple comparison test, and within treatments using Friedman test with Dunn's multiple comparison test (p < 0.05). Data are reported as median (range). RESULTS: Time from start of apnea until hemoglobin desaturation was not significantly different between preoxygenated and nonpreoxygenated hens [26.5 (16-50) seconds and 24.0 (5-57) seconds, respectively; p = 0.25]. No differences in PaO2 between treatments were observed at any time point. CONCLUSIONS AND CLINICAL RELEVANCE: Preoxygenation for 3 minutes before isoflurane mask induction of anesthesia and apnea does not significantly increase time until desaturation in hens.

HYPERTENSIVE HEART DISEASE AND ENCEPHALOPATHY IN A CENTRAL BEARDED DRAGON (POGONA VITTICEPS) WITH SEVERE ATHEROSCLEROSIS AND FIRST-DEGREE ATRIOVENTRICULAR BLOCK.

A 0.5 kg, 5-yr-old male bearded dragon (Pogona vitticeps) presented with a 2-mo history of lethargy, anorexia, and impaired locomotion. Upon physical examination, bradyarrhythmia (heart rate: 20 beats/min) and balance disorders were noted. Electrocardiography revealed a first-degree atrioventricular block (P-R interval: 360 ms). On echocardiography, all cardiac chambers were slightly above normal ranges. Complete blood count, blood biochemistry, and T4 were unremarkable except for mildly elevated aspartate aminotransferase. Adenovirus testing was negative by polymerase chain reaction. Following euthanasia, necropsy revealed marked thickening of the arterial trunks and histopathology confirmed multifocal atherosclerosis of efferent heart vessels, arteriosclerosis of cerebral arterioles, and multifocal spongiosis of brain tissue, more pronounced in the optic chiasma. Owing to its severity, atherosclerosis may have contributed to chronic arterial hypertension with damages to the heart, brain vessels, and brain tissue-optic chiasma.

BAYLISASCARIS PROCYONIS LARVA MIGRANS IN TWO CAPTIVE NORTH AMERICAN BEAVERS (CASTOR CANADENSIS).

Baylisascaris procyonis larva migrans was diagnosed in two North American beavers ( Castor canadensis ) belonging to a zoological park in Clarke County, Georgia. Both beavers presented with neurological signs. One beaver died naturally and despite attempted treatment, the other beaver was euthanatized because of severe clinical signs and poor prognosis. Histologic evaluation of the beavers revealed evidence of parasitic migration characterized by several lesions, including eosinophilic granulomas in various organs, as well as necrotizing eosinophilic and lymphoplasmacytic to granulomatous polioencephalitis, leukoencephalitis and cervical leukomyelitis. This represents the first confirmed case of B. procyonis larva migrans in beaver and the first non-raccoon ( Procyon lotor ) host in the southeastern United States. This report highlights the need for clinicians and diagnosticians to consider baylisascariasis in animals with compatible clinical signs. Preventative measures should be considered for captive animals, because early diagnosis of B. procyonis is challenging, and treatment is often unrewarding.

Subcutaneous administration of hydromorphone (0.2 mg/kg) provides antinociception in ferrets (Mustela putorius furo).

OBJECTIVE: To evaluate antinociceptive efficacy of SC administration of hydromorphone hydrochloride and buprenorphine hydrochloride in ferrets (Mustela putorius furo). ANIMALS: 14 healthy adult ferrets (6 neutered males, 8 spayed females). METHODS: In a randomized, blind, controlled, complete crossover design, all 14 ferrets received a single, SC injection of hydromorphone low dose (0.1 mg/kg), hydromorphone high dose (0.2 mg/kg), buprenorphine low dose (0.02 mg/kg), buprenorphine high dose (0.04 mg/kg), or saline solution (0.2 mL/kg). Sedation and forelimb withdrawal latency from a noxious thermal stimulation were evaluated, and behavior was recorded for a total of 8 hours postinjection. RESULTS: Compared to saline, administration of hydromorphone at 0.2 mg/kg resulted in an estimated increase of withdrawal latencies of 7.4 seconds (95% CI, 3.2 to 11.6) at 60 minutes, of 6.6 seconds (2.4 to 10.8) at 90 minutes, of 6.0 seconds (1.8 to 10.2) at 120 minutes, of 7.0 seconds (2.9 to 11.1) at 180 minutes, and of 4.5 seconds (0.5 to 8.6) at 240 minutes. These differences were statistically significant. Hydromorphone administered at a lower dose and buprenorphine at either dose did not increase withdrawal latencies compared to saline. Based on the sedation score used in this study, signs of sedation increased over time in a similar fashion with all treatments, including saline. Erratic dysphoric-like behaviors occurred in all groups except for saline. CLINICAL RELEVANCE: SC administration of hydromorphone at a dose of 0.2 mg/kg provided antinociception from 1 to 4 hours postinjection. Further validation of sedation scores in ferrets is warranted.

Right atrioventricular valve dysplasia in a meerkat.

A 7-y-old, captive, intact female meerkat (Suricata suricatta) was presented with lethargy, decreased appetite, dyspnea, and distended abdomen. At autopsy, the right atrium was markedly dilated, and the right atrioventricular valve (RAV) was dysplastic with shortened or absent chordae tendineae and direct attachment of the valve to the papillary muscles, which, in turn, were fused and abnormally positioned. The right ventricle was considered to be hypertrophied. Also present were hydrothorax, ascites, atelectasis, and hepatic congestion. A diagnosis of RAV dysplasia was made. Histologic findings included hypertrophy of cardiomyocytes and marked centrilobular hepatic congestion and hemorrhage, which were consistent with right-sided heart failure.

Variation in mineral types of uroliths from ferrets (Mustela putorius furo) submitted for analysis in North America, Europe, or Asia over an 8-year period.

OBJECTIVE: To compare mineral types of naturally occurring uroliths in ferrets (Mustela putorius furo) from North America, Europe, and Asia and to identify potential risk factors associated with cystine urolithiasis in ferrets. SAMPLES: 1,054 laboratory submission records of uroliths obtained from ferrets between January 1, 2010, and December 31, 2018. PROCEDURES: For this cross-sectional study, the medical records databases at 4 diagnostic laboratories were searched for records of submissions of uroliths obtained from ferrets. Data collection included submission date; ferret sex, neuter status, and age; receiving laboratory and continent; and urolith mineral type. Regression analyses were performed to identify variables associated with cystine uroliths. RESULTS: Of the 1,054 urolith submissions, 1,013 were from North America, with 92.6% (938/1,013; 95% CI, 90.8% to 94.1%) cystine uroliths, and 41 were from Europe and Asia, with only 26.8% (11/41; 95% CI, 15.7% to 41.9%) cystine uroliths. Median age was 2.0 years for ferrets with cystine urolithiasis versus 4.0 years for those with other types of uroliths. Submissions were more likely cystine uroliths for ferrets in North America versus Europe and Asia (adjusted OR [aOR], 59.5; 95% CI, 21.4 to 165.6), for ferrets that were younger (aOR, 0.67; 95% CI, 0.58 to 0.77), or for submissions in 2018 versus 2010 (aOR, 21.1; 95% CI, 5.1 to 87.9). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the proportion of submissions that were cystine uroliths dramatically increased in North America between 2010 and 2018. There is an urgent need to determine underlying causes and mitigate cystine urolithiasis in ferrets.

Surgical management of multiple metatarsal fractures in a chinchilla (Chinchilla lanigera).

CASE DESCRIPTION A 3-month-old sexually intact female chinchilla (Chinchilla lanigera) was examined for sudden onset of non-weight-bearing lameness of the right hind limb. CLINICAL FINDINGS On physical examination, the right pes was swollen. An open wound on the medial aspect of the metatarsal region exposed the second metatarsal bone, and the pes was displaced laterally. Radiographs of the right pes revealed oblique displaced fractures of the 4 metatarsal bones. TREATMENT AND OUTCOME Surgical treatment was elected, and enrofloxacin was administered prior to surgery. The protruding fragment of the second metatarsal bone was excised, and the third and fourth metatarsal bones were repaired with intramedullary pins and external skeletal fixation. The chinchilla was bearing weight on the affected limb 9 days after surgery with only mild lameness. The implants were removed 35 days after surgery when radiographs showed bony union of the third and fourth metatarsal bones and continued reduction of the fractures of the second and fifth metatarsal bones. Fifty-six days after surgery, the chinchilla was bearing full weight on the limb, and radiographs showed bony union of the third, fourth, and fifth metatarsal bones. CLINICAL RELEVANCE Findings suggested that intramedullary pinning combined with an epoxy resin external fixator may be an effective technique for metatarsal fracture repair in chinchillas. This method allowed physiologic positioning of the limb and functional hind limb use during fracture healing. Prospective studies of fracture healing in exotic small mammals are indicated.