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Abstract

OBJECTIVE

To evaluate and compare the anesthetic effects of alfaxalone-ketamine-midazolam (AKM) and alfaxalone-ketamine-dexmedetomidine (AKD) in black-tailed prairie dogs (Cynomys ludovicianus).

ANIMALS

9 male black-tailed prairie dogs.

PROCEDURES

Prairie dogs were anesthetized with AKM (6 mg/kg alfaxalone, 30 mg/kg ketamine, and 1.5 mg/kg midazolam) and AKD (6 mg/kg alfaxalone, 30 mg/kg ketamine, and 0.15 mg/kg dexmedetomidine) in a prospective, complete cross-over study. Atipamezole (1.5 mg/kg) after AKD or flumazenil (0.1mg/kg) after AKM was administered 45 minutes after induction of anesthesia. Onset of general anesthesia, physiologic parameters, depth of anesthesia, and time to recovery after reversal administration were evaluated for each treatment.

RESULTS

Both AKM and AKD produced a deep plane of anesthesia in black-tailed prairie dogs that varied in duration. The median induction times for AKM and AKD were 82 and 60 seconds, respectively. The median recovery times for AKM and AKD were 27 and 21 minutes, respectively. There were no significant differences between protocols for induction (P = .37) and recovery (P = .51) times. All measured reflexes were absent in all animals at 5 minutes postinduction, with hindlimb reflexes returning prior to forelimb reflexes. Heart rate was lower but respiratory rate was higher in the AKD treatment. Body temperature decreased significantly for both protocols (P < .001) and was significantly lower with AKM than AKD (P < .001).

CLINICAL RELEVANCE

Both AKM and AKD produced a deep plane of anesthesia in black-tailed prairie dogs. For both protocols, heat support and oxygen support are indicated.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate pneumoperitoneal volumes (laparoscopic working space) in guinea pigs (Cavia porcellus) undergoing pneumoperitoneum via carbon dioxide insufflation at different intra-abdominal pressures (IAPs) (4, 6, and 8 mm Hg) and recumbencies (dorsal, right lateral, and left lateral).

ANIMALS

Six 3- to 4-month-old sexually intact female Hartley guinea pigs.

PROCEDURES

Guinea pigs were anesthetized, intubated, and had an abdominal insufflation catheter placed. A baseline abdominal CT scan was performed. Guinea pigs underwent insufflation, with each IAP given in a random order for 10 to 15 minutes with a washout period of 5 minutes between pressures. Abdominal CT scans were acquired at each IAP and at each recumbency. Pneumoperitoneal volumes were calculated using software.

RESULTS

Increases in IAP increased working space significantly (P < .001). The 6- and 8-mm Hg pressures increased working space from 4 mm Hg by 7.3% and 19.8%, respectively. Recumbent positioning (P = .60) and body weight (P = .73) did not affect working space. Order of IAP had a significant (P = .006) effect on working space. One of the guinea pigs experienced oxygen desaturation and bradycardia at 6- and 8-mm Hg IAP.

CLINICAL RELEVANCE

Although an increased working space occurred at 6 and 8 mm Hg compared to 4 mm Hg, further research is needed concerning the cardiovascular effects of pneumoperitoneum in guinea pigs to determine whether those higher IAPs are safe in this species. An IAP of 6 mm Hg can be considered for laparoscopic cannula placement, followed by a lower IAP for laparoscopic procedures.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVES

Diagnosis of equine septic arthritis is not straightforward, and increasing time between onset, diagnosis, and treatment can have serious consequences for quality of life. Defensins are used in diagnosis of human joint infection. The presence of beta defensins (BDs) in equine synovial fluid and their utility as a biomarker of sepsis has not been investigated; therefore, our objectives were to (1) compare in vitro gene expression of lipopolysaccharide (LPS)-stimulated equine neutrophils to unstimulated neutrophils and (2) compare BD protein expression from normal, aseptically inflamed, and septic equine joints.

ANIMALS

5 horses for isolated neutrophil BD expression and 21 synovial fluid samples from 14 horses.

PROCEDURES

RT-qPCR analysis was performed for BD gene expression of stimulated and unstimulated equine peripheral neutrophils. BD protein expression was evaluated from equine joints with no disease, aseptic inflammation, and septic inflammation using a commercial ELISA designed for horses and analyzed with a Kruskal-Wallis test (significant at P < .05).

RESULTS

A significant increase was noted in expression of BD-3 in LPS stimulated as compared to unstimulated neutrophils. There were no significant differences in BD expression noted between joints with no disease, aseptic inflammation, and septic inflammation. Low case numbers and different types of cases in the aseptic inflammation group were main limitations. BD expression patterns in samples from stimulated equine peripheral neutrophils and synovial fluid were identified.

CLINICAL RELEVANCE

BDs are detectable in equine synovial fluid and can be stimulated from peripheral neutrophils. Further examination is needed to define their role as biomarkers of joint disease.

Open access
in American Journal of Veterinary Research
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare the attenuation of the medial coronoid process (MCP) in dogs with and without arthroscopically confirmed evidence of medial coronoid disease (MCD).

ANIMALS

The database at our institution was searched for cases with thoracic limb lameness, diagnosed with MCD by arthroscopic examination that had CT as part of their investigation and compared with a control group of elbow joints from cadavers euthanized for reasons unrelated to MCD. A total of 84 elbow joints were included that met these criteria.

PROCEDURES

Following CT, a standardized measurement of the MCP was obtained from apex to base and the mean attenuation, SD, and total area were recorded. A comparative measurement was obtained from the proximal radial cortex at the level of the nutrient foramen. Elbow joint arthroscopy was carried out using standard portals, and the modified Outerbridge score was (MOS) used to score elbow joint cartilage. Descriptive and inferential statistics were carried out using MLwiN and R.

RESULTS

Attenuation of the MCP was reduced in dogs with MCD compared with those with no MCD (P < .002). No significant differences were observed in the attenuation between categories of severity (MOS). There was good inter- and intraobserver agreement between measurements (intraclass correlation coefficient = 0.89 and 0.95, respectively).

CLINICAL RELEVANCE

MCP attenuation is reduced in dogs with MCD compared with dogs with no evidence of MCD. This finding may be a useful tool for early detection of MCD, but there is no relationship with arthroscopic lesion severity.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses.

ANIMALS

8 healthy horses.

PROCEDURES

In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood pressures; and central venous and pulmonary artery pressures were measured every 5 minutes; cardiac output was measured by means of thermodilution every 15 minutes. Systemic vascular resistance (SVR) was calculated. Blood samples were collected before and during anesthesia, and plasma AVP concentrations were determined with a validated ELISA. Data were analyzed with repeated-measures ANOVA and Pearson correlations.

RESULTS

HS caused an increase in systolic (P = .003) and mean (P = .023) arterial blood pressures that lasted for 30 minutes. The SVR was increased (P < .001) for 45 minutes with HS compared with the SVR after IS administration. Mean plasma AVP concentration increased (P = .03) 15 minutes after HS administration, with the increase lasting 90 minutes.

CLINICAL RELEVANCE

A bolus of HS resulted in a clinically relevant increase in blood pressure in healthy, isoflurane-anesthetized horses. This effect was attributed to volume recruitment and an increase in SVR. Administration of HS offers an option for improving arterial blood pressure in anesthetized horses.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the effects of combining one-lung ventilation and carbon dioxide insufflation (OLV-CDI) on intrathoracic working space (determined by means of CT) during thoracoscopy in dogs and investigate conditions that could safely improve working space compared with OLV alone.

ANIMALS

6 healthy Beagles.

PROCEDURES

Dogs were anesthetized, and right- or left-sided (n = 3/side) OLV was instituted. On the blocked side, a laparoscopic trocar sleeve was placed in the ninth intercostal space for CDI. CT was performed under 3 conditions: with OLV alone, with OLV-CDI at an intrapleural pressure (IPP) of 3 mm Hg, and with OLV-CDI at an IPP of 5 mm Hg. Working space volume (WSV), ventilation space volume (VSV), and thoracic cavity volume (TCV) were determined from CT images.

RESULTS

With OLV-CDI at an IPP of 3 or 5 mm Hg, WSV and TCV were significantly increased, compared with values obtained during OLV alone. With OLV-CDI at an IPP of 5 mm Hg, VSV and Spo 2 were significantly decreased, compared with values obtained during OLV alone. Additionally, contralateral pneumothorax was observed in 4 dogs at an IPP of 5 mm Hg.

CLINICAL RELEVANCE

Combining OLV and CDI could provide a larger working space than OLV alone, even with an IPP of 3 mm Hg, in dogs of limited size. However, an evaluation of the effects on oxygenation and cardiovascular variables is needed before clinical use.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To assess the feasibility and accuracy of using 2 methods for reduction and alignment of simulated comminuted diaphyseal tibial fractures in conjunction with 3-D–printed patient-specific pin guides.

SAMPLE

Paired pelvic limbs from 8 skeletally mature dogs weighing 20 to 35 kg.

METHODS

CT images of both tibiae were obtained, and 3-D reconstructions of the tibiae were used to create proximal and distal patient-specific pin guides. These guides were printed and used to facilitate fracture reduction and alignment in conjunction with either a 3-D–printed reduction guide or a linear type 1A external fixator. Postreduction CT images were used to assess the accuracy of pin guide placement and the accuracy of fracture reduction and alignment.

RESULTS

The 3-D–printed guides were applied with acceptable ease. Guides for both groups were placed with minor but detectable deviations from the planned location (P = .01), but deviations were not significantly different between groups. Fracture reduction resulted in similar minor but detectable morphological differences from the intact tibiae (P = .01). In both groups, fracture reduction and alignment were within clinically acceptable parameters for fracture stabilization by means of minimally invasive plate osteosynthesis.

CLINICAL RELEVANCE

Virtual surgical planning and fabrication of patient-specific 3-D–printed pin guides have the potential to facilitate fracture reduction and alignment during use of minimally invasive plate osteosynthesis for fracture stabilization.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To assess the potential contamination of commercial raw dog food products with bacteria of the Enterobacterales order that produce extended spectrum beta-lactamase (ESBL) and carbapenemase enzymes, determine risk factors for contamination, and understand isolate genetic diversity.

SAMPLES

A total of 200 canine raw food products.

METHODS

Products were cultured on selective chromogenic agar following enrichment steps. Whole-genome sequencing was performed for isolates that were confirmed to produce an ESBL. Isolates were characterized by antimicrobial resistance genes, and multilocus sequences typing, and compared to other isolates in the NCBI database for clonality. Preservation method and protein sources were assessed as potential risk factors for contamination with ESBL and carbapenemase-producing bacteria of the Enterobacterales order.

RESULTS

No carbapenemase-producing Enterobacterales (CPE) were identified, but ESBL-producing Enterobacterales bacteria were isolated from 20/200 products (10.0%; 95% CI, 7.3 to 16.5%), all of which were frozen. Pork-derived protein source products were 8.1 times (P = .001; 95% CI, 2.53 to 26.2) more likely to carry ESBL-producing Enterobacterales bacteria than other protein sources. WGS analysis confirmed the presence of ESBL genes in a total of 25 distinct isolates (19 Escherichia coli, 5 Klebsiella pneumoniae, and 1 Citrobacter braakii). Genes encoding CTX-M type ESBL enzymes were the most common (24/25 isolates, 96.0%) with blaCTX-M-27 being the most common allele (8/25, 32.0%).

CLINICAL RELEVANCE

Frozen, raw food products may serve as a route of transmission of ESBL-producing Enterobacterales bacteria to companion animals. Veterinarians should advise owners about the risks of raw food diets, including potential exposure to antimicrobial-resistant bacteria.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate changes in ground reaction forces (GRFs) in relation to gait velocity using 2 force plates (FPs) for healthy Beagles.

ANIMALS

18 healthy Beagles were included (body weight, 10.45 ± 1.28 kg; age, 26 ± 11 months).

PROCEDURES

Ten GRF parameters were measured at three gait velocities (walk, 0.9 to 1.2 m/s; trot 1, 1.6 to 2.0 m/s; and trot 2, 2.1 to 2.5 m/s): peak lateral force (PLF), peak medial force (PMF), lateral impulse (LI), medial impulse (MI), peak propulsive force (PPF), peak braking force (PBF), propulsive impulse (PI), braking impulse (BI), peak vertical force (PVF), and vertical impulse (VI).

RESULTS

As velocity increased, the PVF of all limbs increased, the VI of all limbs decreased, and the PPF of the forelimbs increased. At all velocities, PBF and BI were significantly higher than the PPF and PI in forelimbs; however, PBF and BI were significantly lower than the PPF and PI in hindlimbs. There were no significant differences in the PLF, PMF, LI, and MI of the forelimbs and hindlimbs among all velocities. The PLF was significantly higher than the PMF of forelimbs during trot 1 and trot 2.

CLINICAL RELEVANCE

These results may be useful when comparing healthy Beagles with diseased ones when premorbid data are not available. Because the forelimbs are mainly responsible for the braking force, it is suggested that weight bearing is more stable in the forelimbs than in the hindlimbs, which are mainly responsible for the propulsive force, and that a greater force is generated laterally than medially during trot.

Open access
in American Journal of Veterinary Research