Development and evaluation of an anatomically designed and 3D printed device to enhance orotracheal intubation success in rabbits by inexperienced veterinarians.

OBJECTIVE: To assess whether the use of a three-dimensional (3D) printed device enhances the success rate of orotracheal intubation in rabbits. STUDY DESIGN: Prospective, crossover randomized controlled trial. ANIMALS: A total of six mixed-breed rabbits. METHODS: A device to guide the endotracheal tube was designed based on computed tomography images and then manufactured using 3D printing. Rabbits were randomly assigned for intubation by two inexperienced veterinarians using the blind (BLI), borescope- (BOR) or device- (DEV) guided techniques. Success rate, number of attempts, time to success, injury scores and propofol dose were recorded and compared. Significance was considered when p < 0.05. RESULTS: Success rate was higher in DEV (58.3%) than in BLI (8.3%) (p < 0.023), but not different from that in BOR (41.6%). Total time until successful intubation was lower in DEV (45 ± 23 seconds) and BOR (85 ± 62 seconds) than in BLI (290 seconds; p < 0.006). Time for the successful attempt was lower for DEV (35 ± 10 seconds) and BOR (74 ± 43 seconds) than in BLI (290 seconds; p < 0.0001). The propofol dose required was lower for DEV (2.3 ± 1.2 mg kg-1) than for BLI (3.4 ± 1.6 mg kg-1) (p < 0.031), but not different from BOR (2.4 ± 0.9 mg kg-1). Number of attempts and oxygen desaturation events were not different among techniques (p < 0.051 and p < 0.326, respectively). Injury scores [median (range)] before and after attempts were different in BLI [0 versus 1 (0-3), p < 0.005] and BOR [0 (0-1) versus 1 (0-3), p < 0.002] but not in DEV [0 (0-2) versus 0 (0-3), p < 0.109]. CONCLUSIONS AND CLINICAL RELEVANCE: The device facilitated orotracheal intubation with a time similar to the borescope-guided technique but faster than the traditional blind technique.

Implementation of a Low-Cost 3D-Printed Feline Larynx Model for Veterinary Students.

Endotracheal intubation (EI) in domestic cats is an important skill that veterinary students learn in order to perform anesthesia safely in this species. Implementing a 3D-printed larynx model (LaryngoCUBE) during the instruction process may improve student's learning of EI in felines. Twenty-two third-year students performed EI in cats with standard training (ST), and 16 students trained with the model (MT) the day before the laboratory. It was evaluated whether training with the model decreases the time and number of EI attempts, students' perceived difficulty performing EI using a visual analog score (VAS; 0 cm = very easy, 10 cm = extremely difficult; median [minimum-maximum]), and the incidence of failure to perform EI. The EI time on ST (58 [18-160] seconds) was longer, but not statistically different from MT (29 [13-120] seconds; p = .101). The number of EI attempts on ST (2 [1-3]) was higher than MT (1 [1-3]; p = .005). The VAS on the ST and MT were 4.5 (0.0-10.0) cm and 3.0 (0.2-10.0) cm, respectively (p = .029). The failure rate was 27% on the ST and 25% on the MT (p = 1.000). Students who practiced with a larynx model took fewer attempts to perform EI, tended to be faster, and found that EI was easier. However, the EI success rate in MT was not improved.

Evaluation of analgesic, sympathetic and motor effects of 1% and 2% lidocaine administered epidurally in dogs undergoing ovariohysterectomy.

OBJECTIVE: To compare, versus a control, the sensory, sympathetic and motor blockade of lidocaine 1% and 2% administered epidurally in bitches undergoing ovariohysterectomy. STUDY DESIGN: Randomized, blinded, controlled clinical trial. ANIMALS: A total of 24 mixed-breed intact female dogs. METHODS: All dogs were administered dexmedetomidine, tramadol and meloxicam prior to general anesthesia with midazolam-propofol and isoflurane. Animals were randomly assigned for an epidural injection of lidocaine 1% (0.4 mL kg-1; group L1), lidocaine 2% (0.4 mL kg-1; group L2) or no injection (group CONTROL). Heart rate (HR), respiratory rate (fR), end-tidal partial pressure of carbon dioxide (Pe'CO2), and invasive systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures were recorded every 5 minutes. Increases in physiological variables were treated with fentanyl (3 µg kg-1) intravenously (IV). Phenylephrine (1 µg kg-1) was administered IV when MAP was <60 mmHg. Postoperative pain [Glasgow Composite Pain Score - Short Form (GCPS-SF)] and return of normal ambulation were recorded at 1, 2, 3, 4 and 6 hours after extubation. RESULTS: There were no differences over time or among groups for HR, fR, Pe'CO2 and SAP. MAP and DAP were lower in epidural groups than in CONTROL (p = 0.0146 and 0.0047, respectively). There was no difference in the use of phenylephrine boluses. More fentanyl was administered in CONTROL than in L1 and L2 (p = 0.011). GCPS-SF was lower for L2 than for CONTROL, and lower in L1 than in both other groups (p = 0.001). Time to ambulation was 2 (1-2) hours in L1 and 3 (2-4) hours in L2 (p = 0.004). CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of lidocaine (0.4 mL kg-1) reduced fentanyl requirements and lowered MAP and DAP. Time to ambulation decreased and postoperative pain scores were improved by use of 1% lidocaine compared with 2% lidocaine.

A low-cost portable simulator of a domestic cat larynx for teaching endotracheal intubation.

OBJECTIVE: To design and construct an affordable simulator of the cat larynx for training intubation maneuvers and to share the designs for its fabrication. STUDY DESIGN: Research and development study. ANIMALS: A domestic cat. METHODS: The cadaver of a cat, dead by natural causes, was frozen in sternal recumbency with the neck extended and the mouth wide open. A computed tomography image was acquired and used to construct a digital three-dimensional (3D) model of the pharynx and trachea. A digitally adapted model was 3D-printed and used to generate a silicone model of these structures, which was placed within a wooden container. The quality of the simulator was assessed by 46 veterinary anesthesiologists and veterinarians with experience in tracheal intubation maneuvers, and their opinions were obtained through an anonymous questionnaire. RESULTS: Several preliminary prototypes were assessed regarding stability, texture and cost. Finally, a silicone model of a cat larynx (LaryngoCUBE) was produced and encased in a wooden container. Results from the questionnaire showed high scores regarding anatomy, tissue texture and intubation maneuver realism, compared with the real procedure. CONCLUSIONS: and clinical relevance Use of LaryngoCUBE as a training tool may improve the skills of students and reduce the use of animals for teaching endotracheal intubation. Blueprints and computational models are provided online so that the simulator can be fully reproduced.

Sedative and physiologic effects of tiletamine-zolazepam following buccal administration in cats.

OBJECTIVES: The aim of this study was to describe the sedative and some physiological effects of tiletamine-zolazepam following buccal administration (BA) in cats. METHODS: Seven healthy spayed European shorthair cats (three males, four females) were studied twice in this randomized, blinded, crossover study. Each cat received two doses of tiletamine-zolazepam by BA: the low-dose (LD) group consisted of 5 mg/kg of each drug, and the high-dose (HD) group consisted of 7.5 mg/kg of each. Baseline systolic blood pressure (SAP), heart rate (HR), respiratory rate (RR) and a sedation score were recorded prior to administration of each treatment. The same variables plus the percentage of hemoglobin saturated with oxygen as measured by pulse oximetry (SpO2) were recorded at predefined intervals for the next 2 h. RESULTS: All cats completed the study. No retching or vomiting were observed. Hypersalivation was observed in 0/7 and 3/7 for LD and HD groups, respectively (P = 0.2). There were significant changes in scores over time for posture, response to clippers and response to manual restraint for both groups, without differences between groups. RR, HR and SAP changed significantly over time. SAP and RR were significantly lower for the HD than for the LD group. No values for hemoglobin saturation <95% were observed. CONCLUSIONS AND RELEVANCE: BA of tiletamine-zolazepam at the doses studied here is a simple and effective method for chemical restraint in cats, where the LD group had a lower impact on SAP and RR than the HD group.

Mucosal immunization with polymeric antigen BLSOmp31 using alternative delivery systems against Brucella ovis in rams.

Subcellular vaccines against ovine contagious epididymitis due Brucella ovis can solve some shortcomings associated with the use of Brucella melitensis Rev 1. We have demonstrated that the parenteral immunization with polymeric antigen BLSOmp31 emulsified in oil adjuvant conferred significant protection against B. ovis in rams. In our previous studies, we have characterized chitosan microspheres (ChMs) and a thermoresponsive and mucoadhesive in situ gel (Poloxamer 407-Ch) as two novel formulation strategies for the delivery of BLSOmp31 in nasal as well as conjunctival mucosa. In the present work, we evaluated the immunogenicity and protection conferred by the intranasal and conjunctival immunization with these two mucosal delivery systems against B. ovis in rams. BLSOmp31-ChM administered by intranasal route and BLSOmp31-P407-Ch applied by intranasal or conjunctival routes induced systemic, local and preputial IgG and IgA antibody response. Neither formulation showed interference in the serological diagnosis. Thus, mucosal immunization using either formulation induced significant specific cellular immune responses (in vitro and in vivo) and it prevented the excretion of B. ovis in semen. Although these vaccines did not prevent infection in immunized rams, colonization reduction of infected organs and bacterial distribution differed significantly between vaccinated and unvaccinated rams.

Polymeric antigen BLSOmp31 in aluminium hydroxide induces serum bactericidal and opsonic antibodies against Brucella canis in dogs.

Polymeric antigen BLSOmp31 is an immunogenic vaccine candidate that confers protection against Brucella canis in mice. In this preliminary study, the immunogenicity and safety of BLSOmp31 adsorbed to aluminum hydroxide gel (BLSOmp31-AH) were evaluated in Beagle dogs. In addition, the potential to elicit serum antibodies with complement-dependent bactericidal activity and/or to enhance phagocytosis by neutrophils were analyzed. Dogs were immunized three times with BLSOmp31-AH by subcutaneous route, followed by an annual booster. The vaccine elicited specific antibodies 3 weeks after the first immunization. Annual booster induced comparable antibody response as the primary series. Humoral immune response stimulated by BLSOmp31-AH did not interfere with routine agglutination test for canine brucellosis. Antibodies demonstrated a high complement-dependent bactericidal activity against B. canis. Moreover, opsonization by immune serum not only stimulated binding and uptake of the bacteria by neutrophils but effectively enhanced the destruction of B. canis. Specific IgG was detected in 3/4 immunized dogs in preputial secretions. The antibody profile corresponded to a marked Th2 response, since IgG1 prevailed over IgG2 and cellular immune response was not detected in vitro or in vivo. These results require further evaluation in larger field studies to establish the full prophylactic activity of BLSOmp31 against canine brucellosis.

Evaluation of the efficacy of outer membrane protein 31 vaccine formulations for protection against Brucella canis in BALB/c mice.

Canine brucellosis is an infectious disease caused by the Gram-negative bacterium Brucella canis. Unlike conventional control programs for other species of the genus Brucella, currently there is no vaccine available against canine brucellosis, and preventive measures are simply diagnosis and isolation of infected dogs. New approaches are therefore needed to develop an effective and safe immunization strategy against this zoonotic pathogen. In this study, BALB/c mice were subcutaneously immunized with the following: (i) the recombinant Brucella Omp31 antigen formulated in different adjuvants (incomplete Freund adjuvant, aluminum hydroxide, Quil A, and Montanide IMS 3012 VGPR), (ii) plasmid pCIOmp31, or (iii) pCIOmp31 plasmid followed by boosting with recombinant Omp31 (rOmp31). The immune response and the protective efficacy against B. canis infection were characterized. The different strategies induced a strong immunoglobulin G (IgG) response. Furthermore, spleen cells from rOmp31-immunized mice produced gamma interferon and interleukin-4 (IL-4) after in vitro stimulation with rOmp31, indicating the induction of a mixed Th1-Th2 response. Recombinant Omp31 administered with different adjuvants as well as the prime-boost strategy conferred protection against B. canis. In conclusion, our results suggest that Omp31 could be a useful candidate for the development of a subcellular vaccine against B. canis infection.

The vaccine candidate BLSOmp31 protects mice against Brucella canis infection.

Canine brucellosis represents a major reproductive problem worldwide and it is considered a zoonotic disease. New approaches are therefore urgently needed to develop an effective and safe immunization strategy against Brucella canis. In the present study, BALB/c mice were subcutaneously immunized with the recombinant chimera rBLSOmp31 formulated in different adjuvants. The different strategies induced a vigorous immunoglobulin G (IgG) response, with high titers of IgG1 as well as IgG2. Besides, spleen cells from rBLSOmp31-immunized mice produced gamma interferon and IL-4, suggesting the induction of a mixed Th1-Th2. Vaccination with rBLSOmp31-IFA formulation provided the best protection levels comparable with that given by control vaccines. None of the immunization strategies induced serological interference in diagnosis. Hitherto, this is the first report that a recombinant vaccine confers protection against B. canis in mice.

Immune response and serum bactericidal activity against Brucella ovis elicited using a short immunization schedule with the polymeric antigen BLSOmp31 in rams.

Brucella ovis is the etiologic agent of ovine brucellosis. The control measures for this disease are periodical diagnosis by serological tests and/or bacteriological culture and culling of positive animals. Vaccination with Brucella melitensis Rev 1 is recommended when prevalence is high. This attenuated strain vaccine gives protection against B. ovis but it has important disadvantages associated with the development of antibodies interfering with serodiagnosis, virulence for humans and the prohibition of its use in countries considered free of B. melitensis. Consequently, there is a need for new safe and effective brucellosis vaccines to be developed. We have previously reported that the polymeric subcellular vaccine BLSOmp31 confers protection against experimental challenge with B. ovis when rams are immunized three times. In the present work we evaluated and characterized, along 56 weeks after the first immunization of adult rams, the evolution of the immune response elicited by BLSOmp31 using a short immunization schedule.

The polymeric antigen BLSOmp31 confers protection against Brucella ovis infection in rams.

We have engineered the polymeric vaccine BLSOmp31 by decorating the highly immunogenic and decameric Brucella lumazine synthase with an exposed loop of the Brucella outer membrane protein Omp31. In the present study, we have immunized different groups of rams with the recombinant chimera rBLSOmp31 in two different adjuvants (Incomplete Freund Adjuvant-IFA and QUIL A) and with the plasmid pCIBLSOmp31 administered either by i.m. injection alone or by using electroporation. In addition, we have used a heterologous prime-boost strategy consisting of repeated pCIBLSOmp31 electroporation priming followed by a single protein boost. Both, chimera rBLSOmp31 in IFA and the prime-boost strategy induced the highest IgG specific antibodies with bacteriolytic activity. While electroporation-enhanced humoral immune responses as compared to pCIBLSOmp31 injection alone, the highest levels of specific IFN-gamma and protection against bacterial challenge were achieved with prime-boost (76%) and chimera rBLSOmp31 in IFA (63%). Taken together these results strongly support the usefulness of the chimera BLSOmp31 as a vaccine against Brucella ovis in ovine brucellosis.